Letteratura scientifica selezionata sul tema "Myocarde – Histologie"

The paper presents the results of macro- and microscopic structure of cattle heart on the organ-, tissue- and cell levels. The samples of the selected material (n = 5) were preserved in a 10–12 % water solution of neutral formaline with its further charging into wax. Histologic sections not more than 10 mkm were made from wax blocks by using a sliding microtome MC-2. Hematoxilin- and eosin staining of histological sections by Heydengine technique was used for studying cell morphology, carrying out morphometrical studies and for receiving review samples. Histoarchitecture of the structural parts of the heart (ventricle and auricle) and their morphometrical parameters were studied on the histological preparations using the light microscopy technique. The experimantal part of the scientific research was carried out in compliance with the requirements of “European Convention for the Protection of Vertebrate Animals used for Experimantal and other Scientific Purposes” (Strussburg, 1986). The cattle heart is located in a thorax between two lungs, in front of a diaphragm and shifted left. In the 3rd–4th rib region the heart adjacents to a thoracic wall. The heart apex is in the 5th rib region. The absolute weight of a cattle heart equals 2143.27 ± 38.76 g, the relative weight equals – 0.43 ± 0.006 %. The net weight of the heart without the epicardial fat equals 1926.12 ± 31.12 g. Herewith, the weight of the aortic ventricle equals 978.54 ± 19.52 g, the weight of the pulmonic ventricle equals 554.17 ± 14.21 g, the weight of both ventricles equals 1539.08 ± 49.74 g. The auricles weight was the least and equaled 397.18 ± 11.21 g. The ratio of the ventricle weight of the heart to its net weight equals 1:0.2, and the ratio of the weight of the auricle myocard to the weight of the ventricle myocard equals 1:0.26. The heart height equaled 23.08 ± 0.11 сm, width – 13.9 ± 0.18 cm and the circumference – 38.08 ± 0.9 cm. According to the analysis of such liniar measurements, the cattle heart in the animals of the experimental group is characterized as that of an enlarged- and short form. The heart wall consists of three sacs – endocardium, myocard and epicardium. The dominating weight of the heart wall is in a muscular layer (myocard), which consists of transversus stripe muscular fibers which are formed on the basis of mononuclear cells – cardiomyocytes which are interlinked into muscular fibers. According to the cytometric analysis of cardiomyocytes, their largest volume – (11225.73 ± 824.42 mkm3) is observed in the aortic ventricle, smaller – (7963.60 ± 627.09 mkm3) – in a pulmonic ventricle and the smallest – (5361.60 ± 583.91 mkm3) in the auricle cardiomyocytes. Herewith, the volumes of cardiomyocytes nuclei in an aortic ventricle (124.55 ± 7.99 mkm3 and in a pulmonuc ventricle (121.67 ± 7.02 mkm3) are nearly the same, and in the auricle cardiomyocytes the nuclei volume is significantly smaller and it equals 101.05 ± 6.04 mkm3 respectively. Such morphometrical parameters of cardiomyocytes and their nuclei are evidenced in their nuclei-cytoplasmatic ratio, which is the smallest in the cardiomyocytes of an aortic ventricle – 0.0113 ± 0.0068, somewhat larger in a pulmonic ventricle – 0.0156 ± 0.0054 and the largest – 0.0234± 0.0058 in the auricle cardiomyocytes, that is connected with the special properties of the muscular tissue of a myocard which is capable of spontaneous rythmic beatings depending on their morphofunctional load: the ventricles pump the blood from the heart to the body performing the gratest load (the aortic ventricle acts a s a pump, and the pulmonic ventricle acts as a container), the auricles receive the blood which returns to the heart from the animal body, performing somewhat smaller load.

Conventional open harvest of the great saphenous vein (GSV) during CABG results in approximately 7% donor-site complications. Using endoscopic vein harvesting (EVH) the full GSV length can be harvested through a 3 cm incision. This nonsystematic review discusses several key issues concerning EVH, based on an extensive Pubmed search. Found studies show that EVH results in reduced number of wound complications, less postoperative pain, earlier postoperative mobilisation, reduced length of hospital stay, and is more cost-effective. Initial studies did not find significant differences in graft histology, patency, or clinical outcome. However, in 2009 convincing evidence of inferior histological graft properties became available. Furthermore, an observational study showed that EVH resulted in significantly more graft stenosis, was associated with higher mortality, more myocard infarction, and more reinterventions. Most recent publications could not confirm these findings, however larger randomised controlled trials focusing on graft quality are being awaited.

Podocytes contain an intricate actin cytoskeleton that is essential for the specialized function of this cell type in renal filtration. Serum response factor (SRF) is a master transcription factor for the actin cytoskeleton, but the in vivo expression and function of SRF in podocytes are unknown. We found that SRF protein colocalizes with podocyte markers in human and mouse kidneys. Compared with littermate controls, mice in which the Srf gene was conditionally inactivated with NPHS2-Cre exhibited early postnatal proteinuria, hypoalbuminemia, and azotemia. Histologic changes in the mutant mice included glomerular capillary dilation and mild glomerulosclerosis, with reduced expression of multiple canonical podocyte markers. We also noted tubular dilation, cell proliferation, and protein casts as well as reactive changes in mesangial cells and interstitial inflammation. Ultrastructure analysis disclosed foot process effacement with loss of slit diaphragms. To ascertain the importance of SRF cofactors in podocyte function, we disabled the myocardin-related transcription factor A and B genes. Although loss of either SRF cofactor alone had no observable effect in the kidney, deficiency of both recapitulated the Srf-null phenotype. These results establish a vital role for SRF and two SRF cofactors in the maintenance of podocyte structure and function.

A role of YAP and TAZ in vascular and gastrointestinal contractility due to control of myocardin (Myocd) expression, which in turn activates contractile genes, has been demonstrated. Whether this transcriptional hierarchy applies to the urinary bladder is unclear. We found that YAP/TAZ are expressed in human detrusor myocytes and therefore exploited the Itga8-CreERT2 model for deletion of YAP/TAZ. Recombination occurred in detrusor, and YAP/TAZ transcripts were reduced by >75%. Bladder weights were increased (by ≈22%), but histology demonstrated minimal changes in the detrusor, while arteries in the mucosa were inflamed. RT-qPCR using the detrusor demonstrated reductions of Myocd (-79±18%) and Srf along with contractile genes. In addition, the muscarinic receptors Chrm2 and Chrm3 were suppressed (-80±23% and -80±10%) whereas minute increases of Il1b and Il6 were seen. Unlike YAP/TAZ-deficient arteries, Sox9 did not increase, and no chondrogenic differentiation was apparent. Reductions of Myh11, Mylk, and Chrm3 were seen at the protein level. Beyond restraining the smooth muscle cell (SMC) program of gene expression, YAP/TAZ depletion silenced SMC-specific splicing, including exon 2a of Myocd. Reduced contractile differentiation was associated with weaker contraction in response myosin phosphatase inhibition (-36%), and muscarinic activation (reduced by 53% at 0.3 µM carbachol). Finally, short-term overexpression of constitutively active YAP in HEK293 cells increased myocardin (>8-fold) along with archetypal target genes, but contractile genes were unaffected or reduced. YAP and TAZ thus regulate myocardin expression in the detrusor, and this is important for SMC differentiation and splicing as well as for contractility.

Abstract The objective of this research is to determine the effects of turmeric (Curcuma domestica Val) extract administration toward heart histopathologic lesions of male albino Wistar rats + 3 months old exposed by cigarette smoke. Twenty male Wistar rats were divided randomly into four groups of five each: Group I was given neither cigarette smoke exposure nor turmeric extract administration (control) (KI), Group II was given cigarette smoke exposure of 9 cigarettes/ day (KII), Group III was given 1 ml turmeric extract 0.25% (KIII) and Group IV was given cigarette smoke exposure of 9 cigarettes/ day and 1 ml turmeric extract 0.25% (KIV). After 2 months of treatment, necropsy was conducted to all rats and the heart samples were collected to be processed histopatologically and stained routinely with hematoxylin-eosin. The results of the present study indicated that the cigarette smoke caused cardiomyopathy in KII marked by the histopathologic lesions such as vacuolation, homogeneous eosinophilic cytoplasms, edema and necrosis of myocardia, also congestion and mild hemorrhages (KII). Whereas, rats in Groups KI, KIII and KIV had normal histologic structures of myocardia. It is concluded, that turmeric extract could be a preventive herbs toward cardiotoxic effects of cigarette smoke. Further research has to be conducted to determine the anti cardiomyopathy mechanism of turmeric rhizome due to cigarette smoke exposure.

Bottom-up engineering of tissue constructs is being rapidly developed and broadly applied in biomanufacturing. As one type of building block, cell-laden microfibers are promising for reconstruction of oriented structures and functions of linear tissues, such as skeletal muscles, myocardia, and spinal cord tissues. Herein, we propose wet-spinning method with agitating collection, wherein alginate-based material is extruded into an agitated CaCl2 bath with a magnetic rotor acting as the microfiber collector. By applying this method, we achieve rapid fabrication and oriented collection of hydrogel microfibers with diameters ranging from 100 to 400 μm. In addition, we encapsulate myoblasts in the hydrogel to form cell-laden microfibers, which show a high viability (more than 94%) during in vitro culture. Moreover, the method allows to fabricate of cell-laden core–sheath microfibers and hollow microfibers. We also fabricate 3D constructs using various methods of microfiber assembly like weaving and braiding. The assembling results suggest that the proposed method is a promising technology for bottom-up engineering of aligned biomimetic tissue constructs.

Malgré des progrès indéniables dans la compréhension de la fonction cardiaque et dans l’amélioration des techniques médicales et chirurgicales, l'insuffisance cardiaque ischémique représente toujours une cause majeure de mortalité dans le monde De nouvelles approches thérapeutiques, telles que la médecine régénérative et le génie tissulaire, sont développées pour compenser voire se substituer aux tissus endommagés. Une des tentatives de l’ingénierie tissulaire est de reproduire le plus fidèlement possible le comportement mécanique du tissu à traiter. Dans ce travail de thèse, une approche liant la caractérisation mécanique du tissu cardiaque sain avec sa microstructure a été réalisée. A cet effet et afin d’éviter la dégradation des propriétés du matériau due à son asséchement et/ou à sa dé-vascularisation, un protocole expérimental a été défini permettant d’effectuer les mesures dans un environnement proche de son milieu physiologique. Le tissu cardiaque a été ainsi caractérisé à travers l’estimation des modules d’Young suivant deux directions principales par indentations sphériques. Ces résultats ont confirmé ainsi la nature anisotrope du tissu cardiaque. La recherche des durées limites d’exploitation des échantillons après prélèvement (expérimentation ex-vivo) nous a permis de définir une cinétique de rigidification des tissus pouvant être comparée aux techniques de datation utilisées en médecine légale. Une perspective à ces travaux de thèse est l’élaboration d’un matériau de substitution passif dans le but d’obtenir des membranes dont les propriétés mécaniques sont proches du tissu cardiaque. Sur la base de la caractérisation mécanique du myocarde, une modélisation du comportement mécanique d’une bio-prothèse a été définie. Un premier prototype de membrane a été réalisé et expérimenté sur le petit animal. Ces résultats ont constitué une étape indispensable dans le développement d’une assistance biomécanique dans le cadre d’un projet européen FEDER ASCATIM (2018-2021). Enfin, une première transposition de la méthode développée pour le tissu cardiaque a été proposée pour un matériau biologique dont les caractéristiques mécaniques sont peu connues : l’os cortical
Despite undeniable progress of the heart function understanding and in the improvement of medical and surgical techniques, ischaemic heart failure is still a major cause of death worldwide. New therapeutic approaches, such as regenerative medicine and tissue engineering are being developed to compensate or even replace damaged tissues. One of the attempts of tissue engineering is to reproduce as closely as possible the mechanical behavior of the tissue to be treated. In this thesis work, an approach linking the mechanical characterisation of healthy heart tissue with its microstructure was carried out. To this end and in order to avoid the degradation of the material properties due to its drying out and/or de-vascularisation, an experimental protocol was defined to perform the measurements in a context close to its physiological environment. The cardiac tissue was thus characterised through the estimation of Young's modulus in two main directions by spherical indentation. These results thus confirmed the anisotropic nature of the cardiac tissue. The search for the time limits for using the samples after collection (ex-vivo experimentation) enabled us to define a tissue rigidification kinetics which can be compared to the dating techniques used in forensic medicine. One perspective to this thesis work is the development of a passive substitute material in order to obtain membranes whose mechanical properties are close to those of cardiac tissue. On the basis of the mechanical characterization of the myocardium, a model of the mechanical behavior of a bio-prosthesis has been defined. A first membrane prototype has been produced and tested on small animals. These results were an essential step in the development of biomechanical assistance within the framework of a European ERDF ASCATIM project (2018-2021). Finally, a first transposition of the method developed for cardiac tissue was proposed for a biological material whose mechanical characteristics are unknown: cortical bone