Journal articles: 'Urine amino acids'

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Harada, Masashi, Sachise Karakawa, Hiroshi Miyano, and Kazutaka Shimbo. "Simultaneous Analysis of d,l-Amino Acids in Human Urine Using a Chirality-Switchable Biaryl Axial Tag and Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry." Symmetry 12, no. 6 (June 2, 2020): 913. http://dx.doi.org/10.3390/sym12060913.

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Although d,l-amino acids are symmetrical molecules, l-isomers are generally dominant in living organisms. However, it has been found that some d-amino acids also have biological functions. A new method for simultaneously analyzing d,l-amino acids in biological samples is required to allow unknown functions of d-amino acids to be investigated. d-Amino acids in urine are currently receiving increasing amounts of attention, particularly for screening for chronic kidney diseases. However, simultaneously analyzing d,l-amino acids in human urine is challenging because of interfering unknown compounds in urine. In this study, the axially chiral derivatizing agent (R)-4-nitrophenyl-N-[2-(diethylamino)-6,6-dimethyl-[1,1-biphenyl]-2-yl] carbamate hydrochloride was used to allow enantiomers of amino acids in human urine to be simultaneously determined by liquid chromatography electrospray ionization tandem mass spectrometry. The optimized method gave good linearities, precision results, and recoveries for 18 proteinogenic amino acids and their enantiomers and glycine. The chiral-switching method using (S)-4-nitrophenyl-N-[2-(diethylamino)-6, 6-dimethyl-[1,1-biphenyl]-2-yl]carbamate hydrochloride confirmed the expected concentrations of 32 of the 37 analytes. The method was successfully used to determine the concentrations of d-serine, d-alanine, d-asparagine, d-allothreonine, d-lysine, and the d-isomers of 10 other amino acids in five human volunteer urine samples.

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Nagata, Y., R. Konno, Y. Yasumura, and T. Akino. "Involvement of d-amino acid oxidase in elimination of free d-amino acids in mice." Biochemical Journal 257, no. 1 (January 1, 1989): 291–92. http://dx.doi.org/10.1042/bj2570291.

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The physiological role of D-amino acid oxidase was investigated by using mutant ddY/DAO- mice lacking the enzyme. Free D-amino acid concentrations in the mutant mice were significantly higher than those of control ddY/DAO+ mice in kidney, liver, lung, heart, brain, erythrocytes, serum and urine. The results suggest that the enzyme is involved in the catabolism of free D-amino acids in the body, and that free D-amino acids are also excreted into urine.

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Hortin, Glen L., and Bonnie Meilinger. "Cross-Reactivity of Amino Acids and Other Compounds in the Biuret Reaction: Interference with Urinary Peptide Measurements." Clinical Chemistry 51, no. 8 (August 1, 2005): 1411–19. http://dx.doi.org/10.1373/clinchem.2005.052019.

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Abstract Background: Biuret assays for total protein measurement are considered to react with all peptides longer than 2 residues. Some studies using biuret assays of urine suggest that small peptides generally are more abundant than proteins in urine, but it is not clear whether this is a problem of assay specificity. Methods: We analyzed the specificity and kinetics of a biuret reaction for solutions of amino acids, organic compounds, peptides, proteins, and ultrafiltered urine specimens and compared the results with standard clinical assays for protein measurement. Results: The biuret assay cross-reacted with several amino acids, dipeptides, and other organic compounds able to form 5- or 6-member ring chelation complexes with copper. Reactions with amino acids and dipeptides had higher absorbance maxima (blue color) than with larger peptides and proteins (purple). Compounds forming potential 4-, 7-, 8-, or 9-member ring complexes with copper had low reactivity. Amino acid amides, dipeptides, and longer peptides had substantial reactivity, except those containing proline. Proteins and polypeptides had similar biuret reactivities per peptide bond, but reaction kinetics were slower for proteins than peptides. Urine specimens ultrafiltered through 3-kDa–cutoff membranes had substantial biuret reactivity, but absorbance maxima were consistent with cross-reactive amino acids rather than peptides. Conclusions: Many compounds, including amino acids, amino acid derivatives, and dipeptides, cross-react in biuret assays. Our studies improve understanding of the specificity of endpoint and kinetic biuret assays widely used in clinical laboratories. Amino acids, urea, and creatinine contribute to overestimation of urinary peptide content by biuret assays.

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Leeuwenburgh, Christiaan, Polly A. Hansen, John O. Holloszy, and Jay W. Heinecke. "Oxidized amino acids in the urine of aging rats: potential markers for assessing oxidative stress in vivo." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 276, no. 1 (January 1, 1999): R128—R135. http://dx.doi.org/10.1152/ajpregu.1999.276.1.r128.

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Oxidative damage of proteins has been implicated in disease and aging. In vitro studies demonstrate that two unnatural amino acids, o,o′-dityrosine and o-tyrosine, are stable markers of protein oxidation. We have investigated the possibility that assaying these compounds in urine could provide a noninvasive way to determine levels of protein oxidation in vivo. Isotope dilution gas chromatography-mass spectrometry was used to quantify levels of o,o′-dityrosine and o-tyrosine in skeletal muscle and urine of aging rats subjected to two interventions: 1) dietary antioxidant supplementation and 2) exercise training. In both sedentary rats and exercise-trained rats, antioxidant therapy reduced levels of protein-bound o,o′-dityrosine in skeletal muscle. In contrast, antioxidant therapy or exercise training minimally affected o-tyrosine levels in this tissue. Levels of the oxidized amino acids in urine samples mirrored those of skeletal muscle proteins. Quantification of the levels of oxidized amino acids in urine may thus serve as a noninvasive measure of oxidative stress in vivo because they change in parallel with levels of protein-bound oxidized amino acids in skeletal muscle.

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Drotningsvik, Aslaug, Øivind Midttun, Linn Anja Vikøren, Adrian McCann, Per Magne Ueland, Gunnar Mellgren, and Oddrun Anita Gudbrandsen. "Urine and plasma concentrations of amino acids and plasma vitamin status differ, and are differently affected by salmon intake, in obese Zucker fa/fa rats with impaired kidney function and in Long-Evans rats with healthy kidneys." British Journal of Nutrition 122, no. 03 (August 2019): 262–73. http://dx.doi.org/10.1017/s0007114519001284.

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AbstractKidney function affects amino acid metabolism and vitamin status. The aims of the present study were to investigate urine and plasma concentrations of amino acids as well as plasma vitamin status in rats with impaired renal function (Zucker fa/fa rats) and in rats with normal kidney function (Long-Evans rats), and to explore the effects of salmon intake on these parameters and potential biomarkers of salmon intake in both rat strains. Male rats were fed diets with casein as sole protein source (control diet) or 25 % protein from baked salmon and 75 % casein for 4 weeks. Urine concentrations of markers of renal function and most amino acids and plasma concentrations of most vitamins were higher, and plasma concentrations of several amino acids including arginine, total glutathione and most tryptophan metabolites were lower in Zucker fa/fa rats compared with Long-Evans rats fed the control diet. Concentrations of kidney function markers were lower after salmon intake only in Zucker fa/fa rats. A trend towards lower urine concentrations of amino acids was seen in both rat strains fed the salmon diet, but this was more pronounced in Long-Evans rats and did not reflect the dietary amino acid content. Urine 1-methylhistidine, 3-methylhistidine, trimethylamineoxide and creatine concentrations, and plasma 1-methylhistidine and creatine concentrations were higher after salmon intake in both rat strains. To conclude, concentrations of amino acids in urine and plasma as well as vitamin status were different in Zucker fa/fa and Long-Evans rats, and the effects of salmon intake differed by rat strain for some of these parameters.

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Venta, Rafael. "Year-Long Validation Study and Reference Values for Urinary Amino Acids Using a Reversed-Phase HPLC Method." Clinical Chemistry 47, no. 3 (March 1, 2001): 575–83. http://dx.doi.org/10.1093/clinchem/47.3.575.

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Abstract Background: Reversed-phase HPLC (RP-HPLC) has become an alternative to ion-exchange chromatography for amino acid analysis in biological fluids. However, validation studies for its urine application are limited, and the corresponding reference values have not been reported extensively. We studied the long-term performance of a commercial HPLC method for urine amino acid analysis and established specific age-related reference values for urine amino acid excretion. Methods: Method performance was continuously assessed by recovery and precision studies with urine samples and controls, respectively. Healthy individuals were prospectively analyzed throughout a 5-year period. Excretion of individual amino acids, expressed as mmol/mol of creatinine, was included in six age-related groups for random urine samples (0–1 month, 1–12 months, 1–3 years, 3–8 years, 8–16 years, and >16 years) and in two groups for 24-h urine collections (8–16 years and >16 years). Results: Over a 1-year period, CVs for retention times were <0.5% and 3.3% for within- and between-run imprecision, respectively. For amino acid concentrations, within-run CVs were 2.9–17% and between-run CVs were 7.1–46% for the same period. Amino acid recoveries were 78–122%. Reference intervals for 35 amino acids were calculated and compared with the concentrations observed in patients diagnosed with specific pathologies. A few statistically significant differences were found between the reference intervals derived using random and 24-h urine collections. Conclusions: Long-term reliability of the RP-HPLC method for urine amino acid analysis has been demonstrated. Representative age-related reference intervals for the RP-HPLC method in both random urine and 24-h urine collections have been established, and their feasibility for diagnosis of aminoaciduria has been shown. These intervals could serve as a guide for laboratories changing to HPLC methods.

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Fan, Jing, Jing Hong, Jun-Duo Hu, and Jin-Lian Chen. "Ion Chromatography Based Urine Amino Acid Profiling Applied for Diagnosis of Gastric Cancer." Gastroenterology Research and Practice 2012 (2012): 1–8. http://dx.doi.org/10.1155/2012/474907.

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Aim. Amino acid metabolism in cancer patients differs from that in healthy people. In the study, we performed urine-free amino acid profile of gastric cancer at different stages and health subjects to explore potential biomarkers for diagnosing or screening gastric cancer.Methods. Forty three urine samples were collected from inpatients and healthy adults who were divided into 4 groups. Healthy adults were in group A (n=15), early gastric cancer inpatients in group B (n=7), and advanced gastric cancer inpatients in group C (n=16); in addition, two healthy adults and three advanced gastric cancer inpatients were in group D (n=5) to test models. We performed urine amino acids profile of each group by applying ion chromatography (IC) technique and analyzed urine amino acids according to chromatogram of amino acids standard solution. The data we obtained were processed with statistical analysis. A diagnostic model was constructed to discriminate gastric cancer from healthy individuals and another diagnostic model for clinical staging by principal component analysis. Differentiation performance was validated by the area under the curve (AUC) of receiver-operating characteristic (ROC) curves.Results. The urine-free amino acid profile of gastric cancer patients changed to a certain degree compared with that of healthy adults. Compared with healthy adult group, the levels of valine, isoleucine, and leucine increased (P<0.05), but the levels of histidine and methionine decreased (P<0.05), and aspartate decreased significantly (P<0.01). The urine amino acid profile was also different between early and advanced gastric cancer groups. Compared with early gastric cancer, the levels of isoleucine and valine decreased in advanced gastric cancer (P<0.05). A diagnosis model constructed for gastric cancer with AUC value of 0.936 tested by group D showed that 4 samples could coincide with it. Another diagnosis model for clinical staging with an AUC value of 0.902 tested by 3 advanced gastric cancer inpatients of group D showed that all could coincide with the model.Conclusions. The noticeable differences of urine-free amino acid profiles between gastric cancer patients and healthy adults indicate that such amino acids as valine, isoleucine, leucine, methionine, histidine and aspartate are important metabolites in cell multiplication and gene expression during tumor growth and metastatic process. The study suggests that urine-free amino acid profiling is of potential value for screening or diagnosing gastric cancer.

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Kohri, K., M. Takada, Y. Katoh, K. Kataoka, M. Iguchi, and T. Kurita. "Amino acids in urine and plasma of urolithiasis patients." International Urology and Nephrology 21, no. 1 (January 1989): 9–16. http://dx.doi.org/10.1007/bf02549896.

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Schneider, K., M. Neupert, G. Spitler, H. V. Henning, D. Matthaei, and F. Scheller. "Gas chromatography of amino acids in urine and haemofiltrate." Journal of Chromatography B: Biomedical Sciences and Applications 345 (January 1985): 19–31. http://dx.doi.org/10.1016/0378-4347(85)80131-6.

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Moodie, I. M., B. J. Hough, and D. Labadarios. "Determination of amino acids in urine by gas chromatography." Journal of High Resolution Chromatography 12, no. 7 (June 1989): 437–41. http://dx.doi.org/10.1002/jhrc.1240120703.

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Kazandjieva, Jana, Dimitrina Guleva, Assia Nikolova, and Sonya Márina. "Skin Lesions Associated with Dietary Management of Maple Syrup Urine Disease: a Case Report." Serbian Journal of Dermatology and Venereology 7, no. 4 (December 1, 2015): 153–62. http://dx.doi.org/10.1515/sjdv-2015-0013.

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Abstract Leucinosis (maple syrup urine disease - MSUD) is an inherited aminoacidopathy and organic aciduria caused by severe enzyme defect in the metabolic pathway of amino acids: leucine, isoleucine, and valine. The classical variant of the disease is characterized by accumulation of both amino and α-keto acids, particulary the most toxic rapid elevation of circulating leucine and its ketoacid, α-ketoisocaproate, which cause encephalopathy and life-threatening brain swelling. However, patients with the most severe form, classical maple syrup urine disease, may appear normal at birth, but develop acute metabolic decompensation within the first weeks of life with typical symptoms: poor feeding, vomiting, poor weight gain, somnolence and burnt sugar-smelling urine, reminiscent of maple syrup. Early diagnosis and dietary intervention improve the patient’s condition, prevent severe complications, and may allow normal intellectual development. We present a 4-month old infant with leucinosis dignosed 3 months earlier, due to elevated levels of amino acids: leucine, isoleucine and valine. The patient was full-term neonate with an uncomplecated delivery, without any family history of metabolic disorder or consanguinity. The infant was referred to a dermatologist, because of maculopapular exanthema on the scalp, trunk, upper and lower extremities, and exfoliative dermatitis of the perioral, particularly anogenital regions, associated with diarrhea. Skin involvement was associated with poor general condition of the infant exhibiting severe hypotension, anemic syndrome, dyspepsia and neurological symptoms. Exanthema developed a few days after the initiation of nutritional therapy for MSUD: isoleucine-, leucine-, and valine-free powdered medical food (MSUD-2) supplemented with iron. Zink levels were within normal ranges. Rapid skin improvement occurred after adequate branched-chain amino acids supplementation was commenced under regular laboratory control (normal zinc serum level with deficiencies of leucine and valine), skin hygiene with antiseptics, emollients and low potent topical corticosteroids. Treatment of acute metabolic decompensation and dietary restriction of branched-chain amino acids are the main aspects in the management of maple syrup urine disease. Common findings in patients with MSUD include: plasma amino acid imbalance, particularly of essential amino acids, failure to thrive attributed to restriction of particular precursor amino acids and natural proteins, micronutrient deficiencies or higher energy requirement due to chronic illness or inflammation. Due to low intake of branched-chain amino acids, some patients develop skin lesions known as acrodermatitis enteropathica-like syndrome. Here we report a case of an infant who developed acrodermatitis enteropathica-like skin eruptions due to branched-chain amino acid deficiency during treatment of maple syrup urine disease. According to available world literature, this is the first report of acrodermatitis enteropathica-like syndrome in an infant with maple syrup urine disease (leucinosis) in the Republic of Bulgaria.

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Van Barneveld, R. J., E. S. Batterham, D. C. Skingle, and B. W. Norton. "The effect of heat on amino acids for growing pigs." British Journal of Nutrition 73, no. 2 (February 1995): 259–73. http://dx.doi.org/10.1079/bjn19950028.

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Experiments were conducted to determine the effect of heating field peas (Pisum sativum) on the N balance and urine, serum and plasma composition of growing pigs. In the first experiment, four diets containing raw field peas (cv. Wirrega) or field peas heated to 150° (cv. Wirrega), 165° (cv. Wirrega) or 150° (cv. Dundale) for 15 min respectively were formulated to contain 1·15 g ileal digestible N/MJ digestible energy (DE) and 036 g ileal digestible lysine/MJ DE in a sugar-based diet. Digestibility estimates were based on those for the Dundale cultivar of field peas used in previous experiments. Total urine and faeces collection from eight pigs was conducted over two 7 d collection periods with a 7 d diet change-over period. Serial blood sampling from the external jugular vein was conducted on the final day of each collection period. There was no significant difference (P > 0·05) in the N balance or apparent biological value of the field-pea treatments. Pigs fed on diets containing peas heated to 150° (cv. Wirrega) or 165° (cv. Wirrega) had a significantly lower (P < 0·01) daily output of urea and uric acid in the urine, and depressed serum protein and serum urea concentrations. Plasma lysine concentration and daily urine lysine output were not significantly different (P > 0·05) in pigs fed on heated peas. Protein excretion in the urine of pigs fed on diets containing peas heated to 165° increased 3–7 times (depending on estimation technique) the level observed in pigs fed on diets containing raw peas. A second experiment was conducted to determine the apparent ileal digestibility of N and amino acids in cv. Wirrega field peas. This study revealed that N digestibility (0·44) and lysine digestibility (0·35) in peas heated to 165° were significantly lower than the cv. Dundale estimates (0·57 and 0·62 respectively) used in diet formulations. The depressed serum and urine variables in pigs fed on heated peas were attributed to overestimation of digestibility. The results exemplify the fact that it is not possible to draw general conclusions as to the effects of heat on any particular protein concentrate. Variability in N balance experiments and problems associated with urine analysis are suggested as likely reasons for the current study not reflecting poor utilization of ileal digestible lysine from heat-treated field peas. Despite considerable variation in the results, it is possible that a large proportion of non-utilizable amino acids in heated field peas may be excreted from the pig via the urine in the form of a protein.

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Akahoshi, Noriyuki, Shotaro Kamata, Masashi Kubota, Takako Hishiki, Yoshiko Nagahata, Tomomi Matsuura, Chiho Yamazaki, et al. "Neutral aminoaciduria in cystathionine β-synthase-deficient mice, an animal model of homocystinuria." American Journal of Physiology-Renal Physiology 306, no. 12 (June 15, 2014): F1462—F1476. http://dx.doi.org/10.1152/ajprenal.00623.2013.

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The kidney is one of the major loci for the expression of cystathionine β-synthase (CBS) and cystathionine γ-lyase (CTH). While CBS-deficient ( Cbs−/−) mice display homocysteinemia/methioninemia and severe growth retardation, and rarely survive beyond the first 4 wk, CTH-deficient ( Cth−/−) mice show homocysteinemia/cystathioninemia but develop with no apparent abnormality. This study examined renal amino acid reabsorption in those mice. Although both 2-wk-old Cbs−/− and Cth−/− mice had normal renal architecture, their serum/urinary amino acid profiles largely differed from wild-type mice. The most striking feature was marked accumulation of Met and cystathionine in serum/urine/kidney samples of Cbs−/− and Cth−/− mice, respectively. Levels of some neutral amino acids (Val, Leu, Ile, and Tyr) that were not elevated in Cbs−/− serum were highly elevated in Cbs−/− urine, and urinary excretion of other neutral amino acids (except Met) was much higher than expected from their serum levels, demonstrating neutral aminoaciduria in Cbs−/− (not Cth−/−) mice. Because the bulk of neutral amino acids is absorbed via a B0AT1 transporter and Met has the highest substrate affinity for B0AT1 than other neutral amino acids, hypermethioninemia may cause hyperexcretion of neutral amino acids.

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Sokolova, Iryna I., Olena H. Yaroshenko, Svitlana I. Herman, Tetiana V. Tomilina, Karyna V. Skydan, and Maxym I. Skydan. "FEATURES OF DENTAL STATUS AND METABOLISM IN CHILDREN WITH EARLY CHILDHOOD CARIES AGAINST THE BACKGROUND OF CONNECTIVE TISSUE DYSPLASIA." Wiadomości Lekarskie 74, no. 10 (2021): 2503–9. http://dx.doi.org/10.36740/wlek202110125.

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The aim: To assess the dental status of infants suffering from connective tissue dysplasia, with the analysis of some aspects of hydrocarbon and amino acid metabolism (blood, urine) and internal organs status. Materials and methods: 81 infants (aged 14 – 36 months) with multiple dental caries were examined. Among them 39 infants were suffered from connective tissue dysplasia. Results: High prevalence of caries in infants against the background of connective tissue dysplasia compared to their peers in the control group (p <0.05) is established: the caries intensity index and the caries intensity growth index are high in all age groups. Disorders of amino acid and carbohydrate metabolism were observed in infants of the main group. Thus, simultaneous increase of amino acids in the blood and urine was observed in 34 children of the main group in different age groups, and simultaneous increase of amino acids in the blood and urine and carbohydrates in the urine was observed in 25 children in different age groups. In infants of the main group the ultrasound examination of abdominal organs revealed changes in the liver, gallbladder, spleen, pancreas and kidneys. Conclusions: When carrying out endogenous prophylaxis of dental caries in infants with connective tissue dysplasia, it is necessary to take into account the internal organs’ status and thin-layer chromatography data of amino acids and carbohydrates in the blood and urine and to prescribe peroral drugs together with the doctors geneticists.

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Golovanov, S. A., V. N. Sinyukhin, V. A. Tashlitsky, A. V. Sivkov, M. Yu Prosyannikov, N. V. Anokhin, D. A. Voytko, et al. "Urinary excretion of tryptophan, lysine, trimethyllysine, sarcosine, choline and 4-pyridoxic acid in urolithiasis." Experimental and Сlinical Urology 15, no. 1 (March 30, 2022): 68–75. http://dx.doi.org/10.29188/2222-8543-2022-15-1-68-75.

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Introduction. The role of the organic matrix in urinary stones genesis in urolithiasis patients is still unclear. The presence of a large amount of protein in the urinary stones matrix suggests the participation of the protein matrix in lithogenesis. Research of the amino acids spectrum in urine is of great interest so far as amino acids are the part of the matrix proteins of the urinary stone. Material and methods. We analyzed urinary excretion of the following amino acids and low molecular weight compounds: tryptophan, lysine, trimethyllysine, sarcosine, choline and 4-pyridoxine acid. We used ultra-performance liquid chromatography in combination with a TQD mass spectrometer. Results. A higher level of excretion of choline and sarcosine is typical for patients with oxalate stones, compared with healthy people. Uric acid stone patients have high concentration of choline and extremely increased concentration of trimethyllysine in the urine unlike healthy individuals. Very low concentration of trimethyllysine, choline, sarcosine and higher excretion of tryptophan are specific for oxalate urolithiasis, in contrast to urate stone patients. Conclusion. The intensity of amino acids and low molecular weight compounds urinary excretion has characteristic features in patients with various types of urolithiasis and healthy individuals. Indicators of excretion of these amino acids and low molecular weight substances can serve as criteria for the activity of oxalate or urate lithogenesis along with the known metabolic lithogenic factors of urine. We can use it as additional target indicators to assess the success of anti-relapse treatment.

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Frey, Isabelle M., Isabel Rubio-Aliaga, Anne Siewert, Daniela Sailer, Aleksey Drobyshev, Johannes Beckers, Martin Hrabé de Angelis, et al. "Profiling at mRNA, protein, and metabolite levels reveals alterations in renal amino acid handling and glutathione metabolism in kidney tissue ofPept2−/−mice." Physiological Genomics 28, no. 3 (February 2007): 301–10. http://dx.doi.org/10.1152/physiolgenomics.00193.2006.

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PEPT2 is an integral membrane protein in the apical membrane of renal epithelial cells that operates as a rheogenic transporter for di- and tripeptides and structurally related drugs. Its prime role is thought to be the reabsorption of filtered di- and tripeptides contributing to amino acid homeostasis. To elucidate the role of PEPT2 in renal amino acid metabolism we submitted kidney tissues of wild-type and a Pept2−/−mouse line to a comprehensive transcriptome, proteome and metabolome profiling and analyzed urinary amino acids and dipeptides. cDNA microarray analysis identified 147 differentially expressed transcripts in transporter-deficient animals, and proteome analysis by 2D-PAGE and MALDI-TOF-MS identified 37 differentially expressed proteins. Metabolite profiling by GC-MS revealed predominantly altered concentrations of amino acids and derivatives. Urinary excretion of amino acids demonstrated increased glycine and cysteine/cystine concentrations and dipeptides in urine were assessed by amino acid analysis of urine samples before and after in vitro dipeptidase digestion. Dipeptides constituted a noticeable fraction of urinary amino acids in Pept2−/−animals, only, and dipeptide-bound glycine and cystine were selectively increased in Pept2−/−urine samples. These findings were confirmed by a drastically increased excretion of cysteinyl-glycine (cys-gly). Urinary loss of cys-gly together with lower concentrations of cysteine, glycine, and oxoproline in kidney tissue and altered expression of mRNA and proteins involved in glutathione (GSH) metabolism suggests that PEPT2 is predominantly a system for reabsorption of cys-gly originating from GSH break-down, thus contributing to resynthesis of GSH.

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Thuy, Le Phuc, and William L. Nyhan. "High voltage electrophoresis of amino acids in urine containing ampicillin." Clinical Biochemistry 26, no. 5 (October 1993): 389–90. http://dx.doi.org/10.1016/0009-9120(93)90115-m.

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Minale, Genet, Tongchai Saesong, Prapapan Temkitthawon, Neti Waranuch, Nitra Nuengchamnong, Krongkarn Chootip, Natakorn Kamkaew, Teeraporn Kongbangkerd, Jinutda Engsuwan, and Kornkanok Ingkaninan. "Characterization of Metabolites in Plasma, Urine and Feces of Healthy Participants after Taking Brahmi Essence for Twelve Weeks Using LC-ESI-QTOF-MS Metabolomic Approach." Molecules 26, no. 10 (May 15, 2021): 2944. http://dx.doi.org/10.3390/molecules26102944.

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Brahmi essence, developed from Bacopa monnieri (L.) Wettst. standardized extract and mulberry juice, was proven to improve the memory speed of healthy participants aged 55–80 years old, following a 12-week dietary program. However, the metabolites have not yet been reported. Our objective was to characterize the altered metabolites in the plasma, urine, and feces of healthy volunteers after consumption of Brahmi essence for 12 weeks, using the LC-MS metabolomics approach. The altered metabolites were selected from OPLS-DA S-plots; 15 metabolites in the plasma, 7 in the urine, and 17 in the feces samples were tentatively identified by comparison with an online database and literature. The metabolites in the plasma samples were in the classes of amino acids, acylcarnitine, and phospholipids. Benzeneactamide-4-O-sulphate and 3-hydroxyhippuric acid were found in urine samples. The metabolites in the class of amino acids, together with jujubogenin and pseudojujubogenin, were identified in the fecal samples. The aminoacyl-tRNA, aromatic amino acids, and branched-chain amino acid biosynthetic pathways were mainly related to the identified metabolites in all three samples. It could be implied that those metabolites and their pathways might be linked with the effect of Brahmi essence on memory speed.

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Edwards, M. A., S. Grant, and A. Green. "A Practical Approach to the Investigation of Amino Acid Disorders." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 25, no. 2 (March 1988): 129–41. http://dx.doi.org/10.1177/000456328802500202.

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We have, in this paper, highlighted some of the common problems in amino acid analysis in our experience and listed the possible causes for increases in specific amino acids in urine—together with guidance on appropriate follow-up investigations.

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Wang, Dunfang, Xuran Ma, Shanshan Guo, Yanli Wang, Tao Li, Dixin Zou, Hongxin Song, Weipeng Yang, and Yongxiang Ge. "Effect of Huangqin Tang on Urine Metabolic Profile in Rats with Ulcerative Colitis Based on UPLC-Q-Exactive Orbitrap MS." Evidence-Based Complementary and Alternative Medicine 2020 (April 22, 2020): 1–11. http://dx.doi.org/10.1155/2020/1874065.

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As a classic prescription, Huangqin Tang (HQT) has been widely applied to treat ulcerative colitis (UC), although its pharmacological mechanisms are not clear. In this study, urine metabolomics was first analysed to explore the therapeutic mechanisms of HQT in UC rats induced by TNBS. We identified 28 potential biomarkers affected by HQT that might cause changes in urine metabolism in UC rats, mapped the network of metabolic pathways, and revealed how HQT affects metabolism of UC rats. The results showed that UC affects amino acid metabolism and biosynthesis of unsaturated fatty acids and impairs the tricarboxylic acid cycle (TCA cycle). UC induced inflammatory and gastrointestinal reactions by inhibiting the transport of fatty acids and disrupting amino acid metabolism. HQT plays key roles via regulating the level of biomarkers in the metabolism of amino acids, lipids, and so on, normalizing metabolic disorders. In addition, histopathology and other bioinformatics analysis further confirm that HQT altered UC rat physiology and pathology, ultimately affecting metabolic function of UC rats.

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Manabe, S., S. Sassa, and A. Kappas. "Hereditary tyrosinemia. Formation of succinylacetone-amino acid adducts." Journal of Experimental Medicine 162, no. 3 (September 1, 1985): 1060–74. http://dx.doi.org/10.1084/jem.162.3.1060.

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Succinylacetone (SA) (4,6-dioxoheptanoic acid) is an abnormal metabolite produced in patients with hereditary tyrosinemia as a consequence of an inherited deficiency of fumaryl acetoacetate hydrolase activity. Patients with this disease are associated with a number of abnormalities, including aminoaciduria, proteinuria, liver failure, commonly hepatoma, and decreased GSH concentration in the liver. In the course of our studies of tyrosinemia, we found that the urine of patients with this disorder contains material(s) that absorbs light at 315 nm. We investigated the nature of the 315 nm material in detail. SA was found to react with amino acids and protein nonenzymatically, to form stable adducts at physiological temperature and pH. All SA adducts with amino acids and/or proteins exhibited an absorption peak at 315 nm. Although all amino acids reacted with SA, the most reactive amino acid was lysine (Lys), followed, in order, by glycine, methionine, phenylalanine, serine, alanine, and glutamine. SA-adducts were unstable at pH below 6, while they were made considerably more stable after reduction with NaBH4, suggesting that SA forms an adduct via Schiff base formation. High-performance liquid chromatography (HPLC) analysis of urines from patients with tyrosinemia revealed the existence of SA-glycine, SA-methionine, SA-tyrosine, and SA-phenylalanine. After digestion of urines with proteinase K, three more HPLC peaks appeared, which all corresponded to SA-Lys adducts. TLC analysis of SA-Lys showed that SA-Lys could form as many as seven different adducts. No SA-adduct peaks were observed in HPLC in urines from normal subjects, patients with other forms of aminoaciduria, or patients with the nephrotic syndrome. In addition to amino acids and proteins, SA reacted with reduced glutathione (GSH) and formed a stable adduct. These findings suggest that SA adduct formation with amino acids, GSH, and proteins is a significant process occurring in tyrosinemia, and may account for certain of the pathologic findings in this hereditary disorder.

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Alp, Hamit Hakan, Halil İbrahim Akbay, Erdem Çokluk, Zubeyir Huyut, Sıddık Keskin, and Mehmet Ramazan Şekeroğlu. "Within-subject and between-subject biological variation of first morning void urine amino acids in 12 healthy subjects." Clinical Chemistry and Laboratory Medicine (CCLM) 58, no. 11 (October 25, 2020): 1901–9. http://dx.doi.org/10.1515/cclm-2020-0249.

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AbstractBackgroundUrine amino acid analysis is used for the assessment of various diseases. The aim of this study was to estimate the valid biological variation (BV) components (within- and between-subjects) required for the safe clinical application of free urine amino acids.MethodsFirst morning void urine samples were taken from 12 healthy subjects (five females, seven males) once a week for 10 consecutive weeks, and amino acid analysis was performed using an Agilent 6470 triple quadrupole tandem mass spectrometer instrument. The obtained data were subjected to normality, outlier and variance homogeneity analyses prior to coefficient of variation (CV) analysis. Within- and between-subject BV values (CVI and CVG) of 39 amino acids were determined for all subjects. In addition, the index of individuality (II), reference change value (RCV), imprecision, bias and total error were estimated using BV data obtained from our study.ResultsThe CVI values ranged from 8.9 (histidine) to 36.8% (trans-4-hydroxyprolin), while the CVG values ranged from 25.0 (1-methyl-L-histidine) to 63.3% (phenylalanine). The II value of most amino acids was less than 0.6 and ranged between 0.21 and 0.88. The imprecision, bias and total error ranged between 4.45 and 16.6, between 7.69 and 16.6, and between 18.4 and 43.2, respectively.ConclusionsThis study, designed according to a rigorous protocol, has the feature of being the first to give information about BV data of urine amino acids. We believe that the reference intervals have a limitation in the evaluation of consecutive results from an individual, so the use of RCV would be more appropriate.

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Schwahn, B., U. Wendel, P. Schadewaldt, N. Falkenberg, and E. Mönch. "Diurnal changes in plasma amino acids in maple syrup urine disease." Acta Paediatrica 87, no. 12 (January 2, 2007): 1245–46. http://dx.doi.org/10.1111/j.1651-2227.1998.tb00945.x.

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Schadewaldt, P., and U. Wendel. "Metabolism of branched-chain amino acids in maple syrup urine disease." European Journal of Pediatrics 156, S1 (July 25, 1997): S62—S66. http://dx.doi.org/10.1007/pl00014274.

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HALVORSEN, S., O. STOKKE, and L. ELDIARN. "ABNORMAL PATTERNS OF URINE AND SERUM AMINO ACIDS IN METHYLMALONIC ACIDEMIA." Acta Paediatrica 59, no. 1 (January 21, 2008): 28–32. http://dx.doi.org/10.1111/j.1651-2227.1970.tb15510.x.

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Li, Yong, Peggy Sekula, Matthias Wuttke, Judith Wahrheit, Birgit Hausknecht, Ulla T. Schultheiss, Wolfram Gronwald, et al. "Genome-Wide Association Studies of Metabolites in Patients with CKD Identify Multiple Loci and Illuminate Tubular Transport Mechanisms." Journal of the American Society of Nephrology 29, no. 5 (March 15, 2018): 1513–24. http://dx.doi.org/10.1681/asn.2017101099.

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Background The kidneys have a central role in the generation, turnover, transport, and excretion of metabolites, and these functions can be altered in CKD. Genetic studies of metabolite concentrations can identify proteins performing these functions.Methods We conducted genome-wide association studies and aggregate rare variant tests of the concentrations of 139 serum metabolites and 41 urine metabolites, as well as their pairwise ratios and fractional excretions in up to 1168 patients with CKD.Results After correction for multiple testing, genome-wide significant associations were detected for 25 serum metabolites, two urine metabolites, and 259 serum and 14 urinary metabolite ratios. These included associations already known from population-based studies. Additional findings included an association for the uremic toxin putrescine and variants upstream of an enzyme catalyzing the oxidative deamination of polyamines (AOC1, P-min=2.4×10−12), a relatively high carrier frequency (2%) for rare deleterious missense variants in ACADM that are collectively associated with serum ratios of medium-chain acylcarnitines (P-burden=6.6×10−16), and associations of a common variant in SLC7A9 with several ratios of lysine to neutral amino acids in urine, including the lysine/glutamine ratio (P=2.2×10−23). The associations of this SLC7A9 variant with ratios of lysine to specific neutral amino acids were much stronger than the association with lysine concentration alone. This finding is consistent with SLC7A9 functioning as an exchanger of urinary cationic amino acids against specific intracellular neutral amino acids at the apical membrane of proximal tubular cells.Conclusions Metabolomic indices of specific kidney functions in genetic studies may provide insight into human renal physiology.

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Martin, Dierk, and Eckhard Schlimme. "Preparation of Ureidonucleosides of the Threonine Isomers." Zeitschrift für Naturforschung C 49, no. 11-12 (December 1, 1994): 834–42. http://dx.doi.org/10.1515/znc-1994-11-1219.

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The hypermodified ureidonucleoside N6[((9-β-ᴅ-ribofuranosyl-9H-purine-6-yl)amino)carbonyl]- ʟ-threonine (5) is a constituent of transfer ribonucleic acid (tRNA) and is secreted as a tRNA catabolite in body fluids such as blood, milk and urine. Compound 5 and the isomeric ureidonucleosides bearing ᴅ-threonine (9), ʟ-allo- (7) and ᴅ-allo-threonine (11) as side chain moieties were synthesized on a preparative scale. The amido protons of 5 and 9 cause two separate 1H NMR signals whereas 7 and 11 cause multiplets. The 13C NMR signals of all carbon atoms of the allo-amino acid side chains (7, 11) are shifted downfield of the corresponding signals in compounds 5 and 9. The chemically protected intermediate compound adenosine urethane (3) is potentially of interest in the analysis of amino acids because it may be converted to nucleosides of the ureido type by reaction with amino acids in biological matrices.

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Boden, G., L. Tappy, F. Jadali, R. D. Hoeldtke, I. Rezvani, and O. E. Owen. "Role of glucagon in disposal of an amino acid load." American Journal of Physiology-Endocrinology and Metabolism 259, no. 2 (August 1, 1990): E225—E232. http://dx.doi.org/10.1152/ajpendo.1990.259.2.e225.

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Amino acids stimulate the release of glucagon and insulin. To assess the role of aminogenic hyperglucagonemia, we have studied, in healthy young males, the effects of basal (less than 100 pg/ml) and high (200-400 pg/ml) plasma glucagon concentrations on amino acid metabolism during intravenous infusion (0.5 g.h-1.4 h) of a mixture of 15 amino acids. Basal plasma glucagon concentrations were obtained by infusion of somatostatin (0.5 mg/h) plus glucagon (0.25 ng.kg-1.min-1) and high plasma glucagon concentrations by infusion of somatostatin plus glucagon (3.0 ng.kg-1.min-1) or by infusion of amino acids alone. All studies were performed under conditions of euglycemic (83-91 mg/dl) hyperinsulinemia (50-80 microU/ml). Hyperglucagonemia significantly increased 1) net amino acid transport from the extracellular into the intracellular space (by approximately 4%), 2) net degradation of amino acids entering the intracellular space (by approximately 40%), and 3) conversion of degraded amino acids into glucose from 0-10% (basal glucagon) to 70-100% (high glucagon). Hyperglucagonemia did not affect the amount of amino acids excreted in the urine (approximately 4%). We conclude that glucagon plays an important role in the disposition of amino acids by increasing their inward transport, their degradation, and their conversion into glucose.

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Trindade, Fábio, António S. Barros, Jéssica Silva, Antonia Vlahou, Inês Falcão-Pires, Sofia Guedes, Carla Vitorino, et al. "Mining the Biomarker Potential of the Urine Peptidome: From Amino Acids Properties to Proteases." International Journal of Molecular Sciences 22, no. 11 (May 31, 2021): 5940. http://dx.doi.org/10.3390/ijms22115940.

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Native biofluid peptides offer important information about diseases, holding promise as biomarkers. Particularly, the non-invasive nature of urine sampling, and its high peptide concentration, make urine peptidomics a useful strategy to study the pathogenesis of renal conditions. Moreover, the high number of detectable peptides as well as their specificity set the ground for the expansion of urine peptidomics to the identification of surrogate biomarkers for extra-renal diseases. Peptidomics further allows the prediction of proteases (degradomics), frequently dysregulated in disease, providing a complimentary source of information on disease pathogenesis and biomarkers. Then, what does urine peptidomics tell us so far? In this paper, we appraise the value of urine peptidomics in biomarker research through a comprehensive analysis of all datasets available to date. We have mined > 50 papers, addressing > 30 different conditions, comprising > 4700 unique peptides. Bioinformatic tools were used to reanalyze peptide profiles aiming at identifying disease fingerprints, to uncover hidden disease-specific peptides physicochemical properties and to predict the most active proteases associated with their generation. The molecular patterns found in this study may be further validated in the future as disease biomarker not only for kidney diseases but also for extra-renal conditions, as a step forward towards the implementation of a paradigm of predictive, preventive and personalized (3P) medicine.

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Parvy, P. R., J. I. Bardet, D. M. Rabier, and P. P. Kamoun. "Age-related reference values for free amino acids in first morning urine specimens." Clinical Chemistry 34, no. 10 (October 1, 1988): 2092–95. http://dx.doi.org/10.1093/clinchem/34.10.2092.

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Abstract We determined age-related reference values for urinary free amino acids (in mmol/mol creatinine) in first morning urine specimens from 360 control subjects who were divided into nine age groups: birth to 1 month, 1-6 months, 6-12 months, 1-2 years, 2-4 years, 4-7 years, 7-10 years, 10-13 years, and older than 13 years. Except for taurine and 3-methylhistidine, the concentration of all the amino acids decreased with increasing age. The use of these results to detect aminoacidopathies and tubulopathies is discussed.

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Primiano, Aniello, Silvia Persichilli, Pietro Manuel Ferraro, Riccardo Calvani, Alessandra Biancolillo, Federico Marini, Anna Picca, Emanuele Marzetti, Andrea Urbani, and Jacopo Gervasoni. "A Specific Urinary Amino Acid Profile Characterizes People with Kidney Stones." Disease Markers 2020 (June 30, 2020): 1–7. http://dx.doi.org/10.1155/2020/8848225.

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Background. Urolithiasis is the process of stone formation in the urinary tract. Its etiology is only partly known, and efficient therapeutic approaches are currently lacking. Metabolomics is increasingly used in biomarkers discovery for its ability to identify mediators of relevant (patho)physiological processes. Amino acids may be involved in kidney stone formation. The aim of the present study was to investigate the presence of an amino acid signature in stone former urine through a targeted metabolomic approach. Methods. A panel of 35 amino acids and derivatives was assessed in urines from 15 stone former patients and 12 healthy subjects by UPLC-MS. Partial Least Squares Discriminant Analysis (PLS-DA) was used to define amino acid profiles of cases and controls. Results and Discussion. Our approach led to the definition of a specific amino acid fingerprint in people with kidney stones. A urinary amino acid profile of stone formers was characterized by lower levels of α-aminobutyric acid, asparagine, ethanolamine, isoleucine, methionine, phenylalanine, serine, tryptophan, and valine. Metabolomic analysis may lend insights into the pathophysiology of urolithiasis and allow tracking this prevalent condition over time.

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Dantzler, W. H., and S. Silbernagl. "Specificity of amino acid transport in renal papilla: microinfusion of Henle's loops and vasa recta." American Journal of Physiology-Renal Physiology 261, no. 3 (September 1, 1991): F495—F504. http://dx.doi.org/10.1152/ajprenal.1991.261.3.f495.

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Amino acids can be reabsorbed distal to tips of Henle's loops and may be recycled between loops and vasa recta in rat papilla. Transport specificity was examined during continuous microinfusions of ascending Henle's loops and vasa recta with radiolabeled amino acids. Percent of recovered radiolabel as intact amino acid was also determined. Previous data indicated that, relative to simultaneously microinfused inulin, 30-40% of radiolabeled L- and D-Ala, L-Glu, L-Glu(NH2), and Gly, but no taurine (Tau) or mannitol, microinfused into Henle's loops was reabsorbed. In the present study, reabsorption was shown to involve intact L- and D-Ala, D-Glu, and L-Ser. L-Phe (50 mM) in infusate had no effect on reabsorption of L-Ala (2.5 mM) or L-Glu(NH2) (42.6 microM), and D-Asp (50 mM) had no effect on reabsorption of L-Glu (1.5 mM). Thus reabsorption from Henle's loops is not stereospecific, not different for neutral and acidic amino acids, and not inhibited by competitive inhibitors of proximal tubule amino acid transport, but it was not completely nonspecific and not a simple leak. Previous vasa recta microinfusions suggested that Ala could move directly from vasa recta to tubules. These studies were extended with simultaneous collections from ipsilateral and contralateral kidneys. Relative to simultaneously microinfused inulin, 40–50% of radiolabeled L- and D-Ala, L-Glu, and L-Glu(NH2) and 30% of L-Ser microinfused into ascending vasa recta appeared intact in urine from ipsilateral kidney, whereas only 1–3% appeared in urine from contralateral kidney. Fifty percent of infused D-Glu was excreted intact by each kidney; 70% of infused Tau was excreted intact by ipsilateral kidney, and 22% was excreted by contralateral kidney. L-Phe (50 mM) in infusate inhibited appearance of L-Ala (2.5 mM) and D-Ala (10 mM) but not L-Glu(NH2) (42.6 microM) in ipsilateral urine. D-Asp (50 mM) inhibited appearance of L-Glu (1.5 mM), and beta-Ala (50 mM) inhibited appearance of Tau (78 microM) in ipsilateral urine. Thus some amino acids can move directly from vasa recta into tubules (probably descending thin limbs of Henle's loops) by a process showing significant specificity.

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Chun, Sukyung, Phil-Kyung Shin, Myung Sunny Kim, Min Jung Kim, Hae-Jeung Lee, Seon-Joo Park, Dae-Young Kwon, and Sang-Woon Choi. "Urine Organic Acids Can Determine the Metabolic Effects of Traditional Korean Diet, a Cardiometabolic Diet." Current Developments in Nutrition 4, Supplement_2 (May 29, 2020): 14. http://dx.doi.org/10.1093/cdn/nzaa040_014.

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Abstract Objectives Urine organic acids are water-soluble chemical compounds excreted in the urine that are intermediates in many metabolic pathways. Because excess metabolites are excreted in the urine, they may reflect the metabolic status. We investigated whether urine organic acids can determine the metabolic influence of traditional Korean diet (K-diet), a cardiometabolic diet. Methods Fifty two healthy premenopausal women were recruited into a 2 × 2 crossover study with two different diets, K diet and control diet (Westernized current Korean diet). Each diet was provided alternately to all subjects for 1 month with 1 month washout period. Blood and urine samples were collected with anthropometric measurements. Sixty five urine organic acids were measured by LC-MS/MS. Results In the K-diet group, the mean difference of triglyceride (−6.58 ± 4.80 vs −26.35 ± 6.05 mg/dL, P = 0.012), total cholesterol (−12.77 ± 2.78 vs −30.02 ± 2.65 mg/dL, P < 0.001) and LDL- cholesterol (−5.52 ± 2.30 vs −15.88 ± 2.29 mg/dL, P = 0.002) were significantly lower compared to the control group. Body weight and body mass index were also lowered in the K-diet group. Among 65 urine organic acids, TCA cycle associated α-ketoglutarate (21.73 ± 1.27 vs 19.05 ± 1.15 ug/mg creatinine, P = 0.008), malate (1.61 ± 0.10 vs 1.34 ± 0.09, P = 0.008) and isocitrate (22.90 ± 0.68 vs 21.27 ± 0.54, P = 0.014) were lowered in the K-diet group, while citrate (249.16 ± 16.96 vs 324.42 ± 21.18, P = 0.001) and furmarate (0.51 ± 0.03 vs 0.65 ± 0.06, P = 0.029) were elevated in the control group. α-Keto-β-methylvalerate (1.46 ± 0.09 vs 1.09 ± 0.07, P = 0.001), α-ketoisovalerate (0.22 ± 0.02 vs 0.16 ± 0.02, P = 0.012) and methylmalonate (1.30 ± 0.06 vs 1.00 ± 0.06, P < 0.001), which are associated with branched chain amino acid metabolism, were decreased in the K-diet group. Adipate (0.90 ± 0.07 vs 0.65 ± 0.04, P < 0.001) and α-ketoisocaproate (0.46 ± 0.02 vs 0.38 ± 0.02, P = 0.002), which are associated with fatty acid metabolism, were also decreased in the K-diet group. Conclusions K-diet improves clinical parameters and alters urine organic acids associated with TCA cycle and metabolisms of fatty acids and branched-chain amino acid, suggesting that urine organic acids can be useful endpoints to determine the metabolic effects of K-diet and even other diets. Funding Sources Korea Food Research Institute.

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Freeto, Scott, Donald Mason, Jie Chen, Robert H. Scott, Srinivas B. Narayan, and Michael J. Bennett. "A rapid ultra performance liquid chromatography tandem mass spectrometric method for measuring amino acids associated with maple syrup urine disease, tyrosinaemia and phenylketonuria." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 44, no. 5 (September 1, 2007): 474–81. http://dx.doi.org/10.1258/000456307781646012.

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Background: Patients with inherited disorders of amino acid metabolism including maple syrup urine disease, tyrosinaemia and phenylketonuria on dietary management require frequent monitoring of disease-relevant plasma amino acids in order to optimize therapeutic benefit. Poorly controlled maple syrup urine disease in particular may result in catastrophic metabolic decompensation. Most methods for monitoring amino acid concentrations are time-consuming and have clinically impractical turnaround times, particularly when the required time to run standards and control samples is taken into account. Methods: We have analysed plasma amino acids using standard ion-exchange chromatography with ninhydrin detection in an amino acid analyser and compared the data with that obtained for the same samples using ultra-performance liquid chromatography (UPLCTM) separation with detection by tandem mass spectrometry. Results: The two methodologies compared very well for the measurement of six important amino acids with correlation coefficients greater than 0.96 for all. The time for sample preparation was longer for the UPLC methodology as batched derivatization and evaporation is required but UPLC-tandem mass spectrometry generated sample results every 8 min while conventional ion-exchange chromatography took almost 1 h per sample. Conclusion: UPLC-tandem mass spectrometry generates data that compares well with existing 'gold standard' methodologies but significantly reduces sample turnaround time. Decreasing the turnaround time for amino acid analyses is very likely to improve clinical care for patients with amino acid disorders as dietary adjustments can be made sooner.

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Sheikh, Kashif, Germán Camejo, Boel Lanne, Torbjörn Halvarsson, Marie Rydén Landergren, and Nicholas D. Oakes. "Beyond lipids, pharmacological PPARα activation has important effects on amino acid metabolism as studied in the rat." American Journal of Physiology-Endocrinology and Metabolism 292, no. 4 (April 2007): E1157—E1165. http://dx.doi.org/10.1152/ajpendo.00254.2006.

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PPARα agonists have been characterized largely in terms of their effects on lipids and glucose metabolism, whereas little has been reported about effects on amino acid metabolism. We studied responses to the PPARα agonist WY 14,643 (30 μmol·kg−1·day−1 for 4 wk) in rats fed a saturated fat diet. Plasma and urine were analyzed with proton NMR. Plasma amino acids were measured using HPLC, and hepatic gene expression was assessed with DNA arrays. The high-fat diet elevated plasma levels of insulin and triglycerides (TG), and WY 14,643 treatment ameliorated this insulin resistance and dyslipidemia, lowering plasma insulin and TG levels. In addition, treatment decreased body weight gain, without altering cumulative food intake, and increased liver mass. WY 14,643 increased plasma levels of 12 of 22 amino acids, including glucogenic and some ketogenic amino acids, whereas arginine was significantly decreased. There was no alteration in branched-chain amino acid levels. Compared with the fat-fed control animals, WY 14,643-treated animals had raised plasma urea and ammonia levels as well as raised urine levels of N-methylnicotinamide and dimethylglycine. WY 14,643 induced changes in a number of key genes involved in amino acid metabolism in addition to expected effects on hepatic genes involved in lipid catabolism and ketone body formation. In conclusion, the present results suggest that, in rodents, effects of pharmacological PPARα activation extend beyond control of lipid metabolism to include important effects on whole body amino acid mobilization and hepatic amino acid metabolism.

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Piestansky, Juraj, Dominika Olesova, Jaroslav Galba, Katarina Marakova, Vojtech Parrak, Peter Secnik, Peter Secnik, et al. "Profiling of Amino Acids in Urine Samples of Patients Suffering from Inflammatory Bowel Disease by Capillary Electrophoresis-Mass Spectrometry." Molecules 24, no. 18 (September 14, 2019): 3345. http://dx.doi.org/10.3390/molecules24183345.

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Urine represents a convenient biofluid for metabolomic studies due to its noninvasive collection and richness in metabolites. Here, amino acids are valuable biomarkers for their ability to reflect imbalances of different biochemical pathways. An impact of amino acids on pathology, prognosis and therapy of various diseases, including inflammatory bowel disease (IBD), is therefore the subject of current clinical research. This work is aimed to develop a capillary electrophoresis-tandem mass spectrometry (CE-MS/MS) method for the quantification of the 20 proteinogenic amino acids in human urine samples obtained from patients suffering from IBD and treated with thiopurines. The optimized CE-MS/MS method, with minimum sample preparation (just “dilute and shoot”), exhibited excellent linearity for all the analytes (coefficients of determination were higher than 0.99), with inter-day and intra-day precision yielding relative standard deviations in the range of 0.91–15.12% and with accuracy yielding relative errors in the range of 85.47–112.46%. Total analysis time, an important parameter for the sample throughput demanded in routine practice, was shorter in ca. 17% when compared to established CE-MS methods. Favorable performance of the proposed CE-MS/MS method was also confirmed by the comparison with corresponding ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) method. Consistent data for the investigated amino acid metabolome were obtained using both methods. For the first time, the amino acid profiling by CE-MS approach was applied on the clinical IBD samples. Here, significant differences observed in the concentration levels of some amino acids between IBD patients undergoing thiopurine treatment and healthy volunteers could result from the simultaneous action of the disease and the corresponding therapy. These findings indicate that amino acids analysis could be a valuable tool for the study of mechanism of the IBD treatment by thiopurines.

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Javed, Kiran, Qi Cheng, Adam Carroll, Thy Truong, and Stefan Bröer. "Development of Biomarkers for Inhibition of SLC6A19 (B0AT1)—A Potential Target to Treat Metabolic Disorders." International Journal of Molecular Sciences 19, no. 11 (November 14, 2018): 3597. http://dx.doi.org/10.3390/ijms19113597.

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Recent studies have established that dietary protein restriction improves metabolic health and glucose homeostasis. SLC6A19 (B0AT1) is the major neutral amino acid transporter in the intestine and carries out the bulk of amino acid absorption from the diet. Mice lacking SLC6A19 show signs of protein restriction, have improved glucose tolerance, and are protected from diet-induced obesity. Pharmacological blockage of this transporter could be used to induce protein restriction and to treat metabolic diseases such as type 2 diabetes. A few novel inhibitors of SLC6A19 have recently been identified using in vitro compound screening, but it remains unclear whether these compounds block the transporter in vivo. To evaluate the efficacy of SLC6A19 inhibitors biomarkers are required that can reliably detect successful inhibition of the transporter in mice. A gas chromatography mass spectrometry (GC-MS)-based untargeted metabolomics approach was used to discriminate global metabolite profiles in plasma, urine and faecal samples from SLC6A19ko and wt mice. Due to inefficient absorption in the intestine and lack of reabsorption in the kidney, significantly elevated amino acids levels were observed in urine and faecal samples. By contrast, a few neutral amino acids were reduced in the plasma of male SLC6A19ko mice as compared to other biological samples. Metabolites of bacterial protein fermentation such as p-cresol glucuronide and 3-indole-propionic acid were more abundant in SLC6A19ko mice, indicating protein malabsorption of dietary amino acids. Consistently, plasma appearance rates of [14C]-labelled neutral amino acids were delayed in SLC6A19ko mice as compared to wt after intra-gastric administration of a mixture of amino acids. Receiver operating characteristic (ROC) curve analysis was used to validate the potential use of these metabolites as biomarkers. These findings provide putative metabolite biomarkers that can be used to detect protein malabsorption and the inhibition of this transporter in intestine and kidney.

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Alrige, Mayda, Haneen Banjar, Taghreed Shuaib, Amal Ahmed, and Raghad Gharbawi. "Knowledge-Based Dietary Intake Recommendations of Nutrients for Pediatric Patients with Maple Syrup Urine Disease." Healthcare 11, no. 3 (January 18, 2023): 301. http://dx.doi.org/10.3390/healthcare11030301.

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Maple syrup urine disease (MSUD) is a metabolic disorder characterized by a difficulty to digest and process proteins necessary for growth. To monitor and maintain the ideal growth of children with MSUD, caregivers need to carefully control the consumption of harmful branched-chain amino acids (BCAAs). The dietary limits of amino acids for MSUD patients are recommended and controlled by pediatricians and metabolic dietitians according to age, height, weight, and the prevailing percentage of amino acids in the body. This study introduces an intelligent dietary tool called MSUD Baby Buddy for caregivers of MSUD patients that tracks the amino acids intake out of baby formulas for babies 0–6 months old. This tool aims to provide accurate recommendations of the appropriate daily intake of protein and BCAAs based on the patients’ data, plasma BCAAs, and formula preferences. We use a knowledge-based system, including knowledge acquisition and verification, as well as knowledge management tool validation, and the ripple-down rules are employed for building the system. MSUD Baby Buddy can support the maintenance of adequate amino acid levels and increase awareness about the control of BCAAs. The average usability of MSUD Baby Buddy is 84.25, indicating that the tool is intuitive and may help caregivers to easily determine the recommended doses of formula based on patients’ biometric data and preferred formula. On the other hand, interviews with metabolic dietitians revealed some drawbacks, which were addressed to further improve the tool. MSUD Baby Buddy is expected to help caregivers of MSUD patients to independently track nutrient intake and reduce the number of visits to the pediatrician and metabolic dietitian.

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Lee, Yu-Tsung, Sui-Qing Huang, Ching-Hao Lin, Li-Heng Pao, and Chun-Hui Chiu. "Quantification of Gut Microbiota Dysbiosis-Related Organic Acids in Human Urine Using LC-MS/MS." Molecules 27, no. 17 (August 23, 2022): 5363. http://dx.doi.org/10.3390/molecules27175363.

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Urine organic acid contains water-soluble metabolites and/or metabolites—derived from sugars, amino acids, lipids, vitamins, and drugs—which can reveal a human’s physiological condition. These urine organic acids—hippuric acid, benzoic acid, phenylacetic acid, phenylpropionic acid, 4-hydroxybenzoic acid, 4-hydroxyphenyl acetic acid, 3-hydroxyphenylpropionic acid, 3,4-dihydroxyphenyl propionic acid, and 3-indoleacetic acid—were the eligible candidates for the dysbiosis of gut microbiota. The aim of this proposal was to develop and to validate a liquid chromatography–tandem mass spectrometry (LC-MS/MS) bioanalysis method for the nine organic acids in human urine. Stable-labeled isotope standard (creatinine-d3) and acetonitrile were added to the urine sample. The supernatant was diluted with deionized water and injected into LC-MS/MS. This method was validated with high selectivity for the urine sample, a low limit of quantification (10–40 ng/mL), good linearity (r > 0.995), high accuracy (85.8–109.7%), and high precision (1.4–13.3%). This method simultaneously analyzed creatinine in urine, which calibrates metabolic rate between different individuals. Validation has been completed for this method; as such, it could possibly be applied to the study of gut microbiota clinically.

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Barschak, Alethéa G., Angela Sitta, Marion Deon, Estela N. B. Busanello, Daniella M. Coelho, Franciele Cipriani, Carlos S. Dutra-Filho, Roberto Giugliani, Moacir Wajner, and Carmen R. Vargas. "Amino acids levels and lipid peroxidation in maple syrup urine disease patients." Clinical Biochemistry 42, no. 6 (April 2009): 462–66. http://dx.doi.org/10.1016/j.clinbiochem.2008.12.005.

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Poplawski, NK, JR Harrison, W. Norton, E. Wiltshire, and JM Fletcher. "Urine amino and organic acids analysis in developmental delay or intellectual disability." Journal of Paediatrics and Child Health 38, no. 5 (October 2002): 475–80. http://dx.doi.org/10.1046/j.1440-1754.2002.00032.x.

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42

Tsareva, Ju A., N. I. Zryachkin, M. A. Kuznetsova, and E. V. Bogacheva. "Leucinosis, or maple syrup urine disease (lecture and a clinical case)." Almanac of Clinical Medicine 48, no. 4 (October 22, 2020): 254–62. http://dx.doi.org/10.18786/2072-0505-2020-48-018.

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Maple syrup urine disease (leucinosis, short-chain ketoaciduria, branched-chain disease, branched-chain ketonuria) is an autosomal recessive disorder which is a consequence of the deficient branched-chain alpha ketoacid dehydrogenase complex. There are five subtypes of the disease: classical, intermediate, intermittent, thiamine-dependent and E3-deficient. Leucinosis is characterized by high plasma levels of branched-chain amino acids (leucine, isoleucine and valine) and high urine levels of branched-chain ketoacids, as well as of lactate and pyruvate. Tandem mass spectrometry can be used as a screening method in newborns. Mild disease cannot be identified at screening. The diagnosis should be based on tandem mass spectrometry of a blood sample and aminoacid analysis by gas chromatography of a urine sample. Prenatal diagnosis requires molecular genetic tests. Treatment of maple syrup urine disease is aimed at normalization of plasma branched-chain amino acids levels and includes two main components, namely, life-long diet therapy and active treatment of acute metabolic deterioration episodes. A favorable course of the disease is possible only with early (pre-symptomatic) initiation of treatment. The development of cognitive functions depends on plasma leucine levels. We present a clinical case of delayed diagnosis of leucinosis, despite its early clinical manifestation, leading to irreversible consequences for the patient.

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Priyadarshini, Abhishek Negi, Chetna Faujdar, Lokesh Nigam, and Naidu Subbarao. "Exploring the Molecular Level Interaction of Human Serum Albumin with Calcium Oxalate Monohydrate Crystals." Protein & Peptide Letters 28, no. 11 (November 2021): 1281–89. http://dx.doi.org/10.2174/0929866528666210930165426.

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Background: Human serum albumin (HSA) is one of the most abundant proteins in the blood plasma, urine as well as in the organic matrix of renal calculi. Macromolecules present in the urine modulate kidney stone formation either by stimulating or inhibiting the crystallization process. Objective: In the present study, the effect of HSA protein on the growth of calcium oxalate monohydrate crystal (COM) was investigated. Methods: Crystal growth assay was used to measure oxalate depletion in the crystal seeded solution in the presence of HSA. HSA concentrations exhibiting effect on crystal growth were selected for FTIR and XRD analysis. In silico docking was performed on seven different binding sites of HSA. Results: Albumin plays dual role in the growth of calcium oxalate crystallization. FTIR and XRD studies further revealed HSA exerted strain over crystal thus affecting its structure by interacting with amino acids of its pocket 1. Docking results indicate that out of 7 binding pocket in protein, calcium oxalate interacts with Arg-186 and Lys-190 amino acids of pocket 1. Conclusion: Our study confirms the role of HSA in calcium oxalate crystallization where acidic amino acids arginine and lysine bind to COM crystals, revealing molecular interaction of macromolecule and crystal in urolithiasis.

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Mazanova, Natalya N., Yu Zh Gorelova, M. I. Bakanov, E. M. Vasilyeva, and T. A. Letuchay. "CHANGING THE AMINO ACID IN THE URINE OF CHILDREN OF CHILDREN AND ADOLESCENTS UNDER THE INFLUENCE OF MILK «FORMULA ROSTA STANDART»." Medical Journal of the Russian Federation 24, no. 5 (October 15, 2018): 242–48. http://dx.doi.org/10.18821/0869-2106-2018-24-5-242-248.

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Using the method of determining the amino acid spectrum in daily urine is important for conducting early diagnosis of many diseases and hereditary metabolic defects, reflecting the complete picture of the amino acid state in the patient's body. The study of 24-hour urine makes it possible to avoid difficulties with the transportation and storage of biomaterial. Evaluation of the results of the study made it possible to identify the lack of nutrition among schoolchildren, helped to adjust nutrition to weakened children and improve the physical and mental performance of schoolchildren. The examined weakened children did not suffer from this or that form of pathology of metabolism. The presented changes in the concentration of amino acids in the urine of schoolchildren before the reception of the dairy product "Formula Growth Standard" and after taking dairy products demonstrated the modern possibilities of personal selection of diet therapy and improving the quality of life of a teenager.

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Maltsev, S. V., V. M. Davydova, and E. I. Zemlyakova. "Clinic and diagnosis of metabolic nephropathies in children." Kazan medical journal 67, no. 5 (September 15, 1986): 358–60. http://dx.doi.org/10.17816/kazmj70701.

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We examined 70 patients with metabolic nephropathy (51 with oxaluria predominance, 19 with uric acid metabolism disorders). Distribution of patients into groups was carried out according to the results of multistage research, including analysis of pedigree; repeated biochemical studies, clinical and radiological comparisons. Endogenous creatinine clearance, residual nitrogen level, urea in blood, acid-base balance were determined to characterize the functional state of the kidneys. Renal tubular function was assessed by urinary excretion of calcium, phosphates, amino acids, titratable acids, Zimnitsky's test. To detect metabolic disorders we studied uric acid content in blood and urine, oxalic acid and xanthurenic acid content in daily urine.

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Hmimidi, I., H. Lyatim, R. Abilkassem, A. Hassani, A. Agader, and M. Kmari. "Early Diagnosis of Lysinuric Protein Intolerance: A Case Report." Scholars Journal of Medical Case Reports 10, no. 12 (December 3, 2022): 1167–69. http://dx.doi.org/10.36347/sjmcr.2022.v10i12.004.

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Introduction: Lysinuric protein intolerance (LPI) is a metabolic disorder resulting from recessive inherited mutations involving the SLC7A7 gene that control the transport of urea cycle intermediates. Case report: In this study we report a case of a kid who diagnosed with LPI at age of 18 month, he has recurrent vomiting and diarrhea with a break in the height-weight curve, the dosage of orotic acid in the urine which was increased, the chromatography of the amino acids which found a low level of lysine, ornithine and arginine in the blood and increased in the urine suggestive of LPI. Discussion: The defects occur in the y+ LAT1 sub-unit of the cationic amino acids transporter localized in the kidney and also expressed in the lung, spleen and in circulating monocytes and macrophages, which explain that an LPI patient usually comes with hepatosplenomegaly, failure to thrive, aversion to protein rich food, and poor feeding.

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Polberger, Staffan K. T., Irene E. Axelsson, and Niels C. R. Räihä. "Amino Acid Concentrations in Plasma and Urine in Very Low Birth Weight Infants Fed Protein-Unenriched or Human Milk Protein-Enriched Human Milk." Pediatrics 86, no. 6 (December 1, 1990): 909–15. http://dx.doi.org/10.1542/peds.86.6.909.

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Preprandial plasma and urine amino acid concentrations were measured in 28 growing, very low birth weight, appropriate-for-gestational-age infants randomly assigned to either protein-unenriced (n = 14) or human milk protein-enriched (n = 14) human milk. The two groups of infants had similar birth weights (900 to 1500 g) and gestational ages (26 to 32 weeks). The study was initiated at a mean age of 19 days when the infants tolerated full feeding volumes and lasted for a mean time of 28 days. Mean protein intake values were 2.1 ± 0.3 and 3.6 ± 0.3 g/kg per day (mean ± SD) and weight gain values were 26.6 ± 7.4 and 35.1 ± 3.6 g/day in the protein-unenriched and the protein-enriched groups of infants, respectively. Human milk protein enrichment resulted in significantly increased concentrations of all plasma amino acids except serine, taurine, and histidine. Most urine amino acid concentrations correlated with protein intake and with the plasma concentrations, suggesting that the effects of protein quality and quantity can be evaluated by measuring urinary amino acid concentrations alone, thereby making such studies less invasive. Infants fed protein-unenriched human milk had growth rates below the estimated intrauterine rate as well as low plasma and urine amino acid concentrations, indicating suboptimal protein intake levels. When the plasma concentrations of the essential amino acids in tenrichedhe protein-enriched infants from the present study were compared with concentrations found in the literature in fetal and umbilical cord plasma, both were found to be much higher. The plasma essential amino acid concentrations in the well-growing, protein-supplemented infants from the present study corresponded best to plasma concentrations found in breast-fed, growing, term infants at 1 to 3 months of age. It is suggested that preprandial plasma amino acid concentrations found in healthy, growing, breast-fed, term infants can be used as reference standard values when evaluating preprandial plasma amino acid concentrations in appropriate-for-gestational age, very low birth weight infants.

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Nanaware, Harshal R., Sudheer Moorkoth, Nitesh Kumar, Shiny Jasphin, Arya Raveendran, and Bhim Bahadur Chaudhari. "Amino Acids from Urine as Possible Biomarkers for Early Detection of Vancomycin Nephrotoxicity." Indian Journal of Pharmaceutical Education and Research 56, no. 3 (June 30, 2022): 795–803. http://dx.doi.org/10.5530/ijper.56.3.130.

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49

Enwonwu, Cyril O., Xu-Xiang Xu, and Ernest Turner. "Nitrogen Metabolism in Sickle Cell Anemia: Free Amino Acids in Plasma and Urine." American Journal of the Medical Sciences 300, no. 6 (December 1990): 366–71. http://dx.doi.org/10.1097/00000441-199012000-00005.

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50

Chen, H., Y. Xu, and M. P. C. Ip. "Determination of Amino Acids in Urine by Capillary Electophoresis with Indirect UV Detection." Journal of Liquid Chromatography & Related Technologies 20, no. 15 (September 1997): 2475–93. http://dx.doi.org/10.1080/10826079708002717.

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Journal articles on the topic 'Urine amino acids'

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