Academic literature on the topic 'Dopegal'

Abstract Alzheimer’s disease (AD) is a progressive neurodegenerative disease with age as a major risk factor. AD is the most common dementia with abnormal structures, including extracellular senile plaques and intraneuronal neurofibrillary tangles, as key neuropathologic hallmarks. The early feature of AD pathology is degeneration of the locus coeruleus (LC), which is the main source of norepinephrine (NE) supplying various cortical and subcortical areas that are affected in AD. The spread of Tau deposits is first initiated in the LC and is transported in a stepwise manner from the entorhinal cortex to the hippocampus and then to associative regions of the neocortex as the disease progresses. Most recently, we reported that the NE metabolite DOPEGAL activates delta-secretase (AEP, asparagine endopeptidase) and triggers pathological Tau aggregation in the LC, providing molecular insight into why LC neurons are selectively vulnerable to developing early Tau pathology and degenerating later in the disease and how δ-secretase mediates the spread of Tau pathology to the rest of the brain. This review summarizes our current understanding of the crucial role of δ-secretase in driving and spreading AD pathologies by cleaving multiple critical players, including APP and Tau, supporting that blockade of δ-secretase may provide an innovative disease-modifying therapeutic strategy for treating AD.

Dihydroxyphenylglycol (DOPEG), the metabolite of norepinephrine (NE) that arises intraneuronally, was measured together with NE in superfusates collected before, during, and after nerve stimulation and in extracts of dog saphenous vein after superfusion and electrical stimulation (ES). Different concentrations of NE in the synaptic clefts were achieved by treating tissues with corticosterone, corticosterone and yohimbine, corticosterone and cocaine, or by omitting drugs from the superfusate. NE and DOPEG were quantitated by liquid chromatography with electrochemical detection. The time courses of NE overflow and DOPEG efflux into superfusate were followed. The amounts of DOPEG in superfusates under basal conditions were two to four times higher than the amounts of NE and progressively increased during ES except in tissues with neuronal uptake inhibited. NE overflow reached a steady state within the first 6 min of ES. Increased NE concentrations in synaptic clefts resulted in increased DOPEG production except where neuronal uptake was inhibited. The increased DOPEG production during ES appears to reflect the increased rate of neuronal uptake, which results in more NE being available for intraneuronal metabolism. No evidence was found that newly formed DOPEG was delayed in leaving the tissue. Thus the increase in DOPEG production that occurs during ES may be useful as an index of neuronal uptake of NE in dog saphenous vein.

Annotation. Hypertension in pregnant women disimprove the placental function, impairs fetal development and has an adverse effect on the condition of a woman. Usually dopegyt is used to treat gestational hypertension. However, it reduces the microcirculation of blood in the placenta, causing or increasing pre-existing placental dysfunction. Therefore, the aim of the research is to optimize the method of gestational hypertension pharmacotherapy in pregnant women with a set of infusion drugs including pentoxifylline, arginine hydrochloride with levocarnitine and reosorbilact to prevent fetoplacental dysfunction and perinatal pathology in this case. We examined 73 pregnant women, among whom we distinguished 3 groups: first group (n = 30) - pregnant women with GH, who, along with the basic therapy with dopegyt received a complex of infusion solutions (pentoxifylline, a solution containing arginine hydrochloride and levocarnitine, drug reosorbilact); second group (n=20) - patients with gestational hypertension who received only basic therapy with dopegyt; control group (n=23) - women with physiological pregnancy. Studies of the clinical effectiveness of the proposed treatment were evaluated by cases of prevention of perinatal pathology (intrauterine growth restriction of the fetus (IUGR), premature birth, etc.) and the results of clinical, laboratory and instrumental research methods. Criteria for inclusion in the study were: the presence of blood pressure ≥150/100 mm Hg, dopegyt, gestational age from 28 to 36 weeks, singleton pregnancy. Examination of pregnant women was performed using standard clinical, laboratory and instrumental (Doppler ultrasounds) research methods. The analysis of the obtained data was performed using the program “STATISTICA 5.5”. Established that in patients who received our treatment regimen, there was a significant reduction in the development of placental dysfunction (OR 0.30, 95 % CI [0.12-0.74], p=0.009), fetal IUGR (OR 0.33, 95 % CI [0.12-0.96], p=0.042), acute fetal distress (OR 0.25, 95 % CI [0.075-0.83], p=0.02), weakness of childbirth (OR 0,19, 95 % CI [0.04-0.82], p=0.03), reducing the risk of perinatal CNS damage (OR 0.22, 95 % CI [0.05-0.99], p=0.049 ) and reducing the risk of cephalohematoma (OR 0.25, 95 % CI [0.075-0.83], p=0.024).

We determined the relative importance of neuronal and extraneuronal uptake in the metabolism of norepinephrine (NE) released during electrical stimulation (ES) of isolated canine tracheal smooth muscle (TSM). Strips of TSM were labeled with L-[3H]NE (2 X 10(-7) M) and mounted for superfusion. Superfusate was collected continuously before, during, and after ES (15 V, 0.5 ms, 5 Hz). Measurements were made of [3H]NE and its metabolites in superfusate and in tissue. Neuronal uptake followed by metabolism was estimated by measuring the amount of 3,4-dihydroxyphenylglycol (DOPEG). Extraneuronal uptake was estimated by measuring O-methylated metabolites (OMM). ES caused large increases in the efflux of NE, DOPEG, and OMM from TSM. However, the overflow of OMM was six times greater than that of DOPEG. Cocaine (10(-5) M) abolished the increased efflux of DOPEG during ES and enhanced the overflow of NE and OMM. We conclude that extraneuronal uptake constitutes the primary metabolic pathway for NE released from adrenergic nerves innervating TSM.

β-alanil-L-istidina (carnosina) è un peptide endogeno che possiede innumerevoli proprietà (chelante dei metalli, antiossidante, sequestrante delle specie reattive carboniliche). Diversi studi clinici hanno dimostrato un’attività farmacologica della carnosina in malattie su base ossidative, tuttavia il meccanismo dell’attività in vivo non è ancora noto. Questo progetto ha come scopo quello di comprendere il meccanismo in vivo della carnosina. Per far ciò, sono stati sviluppati nuovi metodi analitici di cromatografia liquida accoppiata a spettrometria di massa per la quantificazione in campioni biologici dei peptidi istidinici, loro derivati e gli addotti con le specie reattive carboniliche. Come prima cosa, un metodo analitico basato su una colonna ad interazione idrofiliche è stato sviluppato per l’analisi del carnosinolo in matrici biologiche di modelli animali di sindrome metabolica. La concentrazione di carnosinolo è stata determinata in diversi tessuti e, per la prima volta, l’addotto carnosinolo-acroleina è stato identificato in omogenato di fegato. Questo conferma l’attività del carnosinolo e dei peptidi istidinici come sequestranti delle specie reattive carboniliche in vivo. Tuttavia, è stata identificata l’instabilità metabolica dell’addotto carnosinolo-HNE in diversi tessuti. Saranno quindi necessari ulteriori studi per la caratterizzazione del metabolismo di questi addotti e l’identificazione della corretta entità chimica da ricercare nelle matrici biologiche come indice dell’attività sequestrante di carnosina e derivati. Il metodo basato su colonne ad interazioni idrofiliche è stato anche utilizzato per sviluppare un metodo a rivelazione diretta per determinare l’attività idrolitica del siero umano della carnosina. La carnosinasi serica è stata identificata come principale enzima impiegato nel metabolismo della carnosina. Rispetto ad altri metodi pubblicati in letteratura, quello sviluppato in questo elaborato si basa su una determinazione diretta della carnosina, senza dover effettuare processi complessi di preparazione del campione. I dati ottenuti sono stati convalidati con dati presenti in letteratura, dimostrando che il nostro metodo risulta essere affidabile ed accurato. È stato possibile anche condurre esperimenti di competizione fra substrati naturali e alcune molecole per valutare le principali interazioni substrato/enzima, con l’obiettivo di identificare inibitori della carnosinasi. I dati ottenuti sono stati condivisi con colleghi chimici computazionali che attraverso esperimenti di docking, virtual screening e dinamica molecolare hanno identificato dei possibili inibitori naturali della carnosinasi serica umana. Un nuovo meccanismo d’azione della carnosina è stato approfondito, in quanto recenti pubblicazioni hanno evidenziato un ruolo della carnosina nella prevenzione della formazione di addotti fra la 3,4-diidrofenilglicolaldeide (DOPEGAL), un metabolita intermedio del catabolismo della noradrenalina, e le proteine. La capacità della carnosina di legare covalentemente la DOPEGAL tramite la formazione di un prodotto di Amadori è stata determinata in vitro e in lisato cellulare dove la DOPEGAL è stata formata aggiungendo noradrenalina al lisato enzimaticamente attivo. Studi futuri dovranno caratterizzare la stabilità metabolica di quest’addotto e le caratteristiche della sua formazione in matrici biologiche in quanto risulta essere un interessante biomarcatore di tossicità noradrenalinergica. In fine è stata valutato l’impatto della carnosina e del carnosinolo sul proteoma di cellule endoteliali umane derivanti dalla vena ombelicale. È ormai noto che i farmaci non agiscono unicamente col meccanismo d’azione per il quale sono stati sviluppati, ma possono interferire con l’espressione delle proteine cellulari, aumentandone, o diminuendone l’espressione e di conseguenza attivando o disattivando vie biologiche. Carnosina e carnosinolo non inducono una variazione nell’espressione delle proteine in cellule sane. Questo conferma la sicurezza delle molecole, soprattutto prevedendone un uso come terapia cronica. In futuro l’effetto del trattamento andrà valutato su cellule in condizioni patologiche, per comprendere se, in queste condizioni, carnosina o carnosinolo riescono a influenzare vie metaboliche e risposte cellulari. Sebbene ci siano ancora diverse domande che sono rimaste senza risposta, i dati ottenuti in questo elaborato hanno portato all’aumento della conoscenza del meccanismo d’azione di carnosina e derivati e all’identificazione di composti inibitori della carnosinasi.
β-alanil-L-histidine (i.e. carnosine) is an endogenous peptide that have been extensively characterized for a number of in vitro properties (i.e. metal chelating, antioxidant, reactive carbonyl species quenching). Several clinical trials highlighted the potential benefits of carnosine in the treatment of oxidative stress-based diseases, although the in vivo mechanism of action is not known, yet. The research project herein tries to expand upon the in vivo mechanism of action of carnosine. New analytical methods have been developed by means of liquid chromatography – tandem mass spectrometry for the quantification of histidine dipeptides, their derivatives, and the adducts formed with reactive carbonyl species into biospecimens. A first step was the implementation of hydrophilic interaction chromatography to skip some sample preparation steps and to reduce the chance of systematic errors. The method allowed the quantification of carnosine and carnosinol (a carnosine derivative stable to carnosinase) in biospecimens. Carnosinol tissue distribution in animal models of metabolic syndrome was determined and carnosinol-acrolein adduct was detected for the first time in liver matrices. This finding experimentally confirmed the reactive carbonyl species (RCS quenching activity of histidine dipeptides and derivatives in vivo. However, the metabolic instability of carnosinolHNE adduct was proved and such an evidence requires further studies aiming at understanding the metabolic fate of RCS-adducts to characterize their disposal. Subsequently, a new method for the measurement of carnosine hydrolysis in serum was developed as well. Human serum carnosinase has been identified as the enzyme responsible for such an activity. Compared to other published assays, the method employs a direct detection of the substrate and the use of less sample. Competition experiments with either natural derivatives or other molecules were set to identify hit compounds acting as carnosinase inhibitors. The collected data were shared with computational chemists who identified putative hit compounds via docking, virtual screening, and molecular dynamic approaches. Furthermore, a novel carnosine mechanism of action was studied starting from the evidence that carnosine can prevent the formation of protein adducts with 3,4- dihydroxyphenylglycolaldehyde (DOPEGAL) (i.e. an aldehyde intermediate of norepinephrine metabolism). This could be relevant for the in vivo mode of action of carnosine since DOPEGAL can accumulate in cells because of oxidative stress and as it covalently binds proteins, it can alter their structures and functions. Carnosine quenching activity via the formation of an Amadori product with DOPEGAL was determined in vitro and in cell lysates producing DOPEGAL from enzymatic transformation of norepinephrine. Future studies should be done to characterize the metabolic stability of the adduct and its formation in biospecimens as potential biomarker of norepinephrine toxicity. Finally, the project included proteomics studies on human umbilical vein cells (HUVECs) to assess the impact of carnosine and carnosinol on protein expression. It is widely recognized that drugs exert their pharmacological effects also by an alteration of biological pathways by modifying protein expression. Carnosine and carnosinol have little or no impact on protein expression as detectable on proteome or secretome of healthy endothelial cells. In the future the impact on pathological cells should be carried out as well. These data support the hypothesis of a low toxicity for these molecules, making them suitable candidates for a chronic administration. Although a lot of questions are still unanswered, these data have given new insights in the mechanism of action of carnosine and in the discovery of molecules acting either as carnosine-like compounds or as carnosinase inhibitors.