Chronic sojourn in hypoxic environment results in the structural remodeling of peripheral pulmonary arteries and pulmonary hypertension. We hypothesize that the pathogenesis of changes in pulmonary vascular structure is related to the increase of radical production induced by lung tissue hypoxia. Hypoxia primes alveolar macrophages to produce more hydrogen peroxide. Furthermore, the increased release of oxygen radicals by other hypoxic lung cells cannot be excluded. Several recent reports demonstrate the oxidant damage of lungs exposed to chronic hypoxia. The production of nitric oxide is high in animals with hypoxic pulmonary hypertension and the serum concentration of nitrotyrosine (radical product of nitric oxide and superoxide interaction) is also increased in chronically hypoxic rats. Antioxidants were shown to be effective in the prevention of hypoxia induced pulmonary hypertension. We suppose that the mechanism by which the radicals stimulate of the vascular remodeling is due to their effect on the metabolism of vascular wall matrix proteins. Non-enzymatic protein alterations and/or activation of collagenolytic matrix metalloproteinases may also participate. The presence of low-molecular weight cleavage products of matrix proteins stimulates the mesenchymal proliferation in the wall of distal pulmonary arteries. Thickened and less compliant peripheral pulmonary vasculature is then more resistant to the blood flow and the hypoxic pulmonary hypertension is developed., J. Herget, J. Wilhelm, J. Novotná, A. Eckhardt, R. Vytášek, L. Mrázková, M. Ošťádal., and Obsahuje bibliografii
The slowly metabolized proteins of the extracellular matrix, typically collagen and elastin, accumulate reactive metabolites through uncontrolled non-enzymatic reactions such as glycation or the products arising from the reaction of unsaturated long chain fatty acid metabolites (possessing aldehydic groups). A typical example of these non-enzymatic changes is the formation of advanced glycation end-products (AGEs), resulting from the reaction of carbohydrates with the free amino group of proteins. The accumulation of AGEs and the resulting structural alterations cause altered tissue properties (increased stiffness, reduced elasticity) that contribute to their reduced catabolism and to their aging. Posttranslational nonenzymatic modifications of the proteins of the extracellular matrix (the formation of a typical AGE product - pentosidine) were studied in three types of tissue of three rat strains subjected to a high-fructose diet. Chronic (three-week) hyperglycemia (resulting from fructose loading) caused a significant increase in pentosidine concentration mainly in the aorta and skin of the three rat strains (Lewis, Wistar and hereditary hypertriglyceridemic rats)., K. Mikulíková, A. Eckhardt, J. Kuneš, J. Zicha, I. Mikšík., and Obsahuje bibliografii a bibliografické odkazy
Idiopathic pes equinovarus (clubfoot) is a congenital deformity of the foot and lower leg defined as a fixation of the foot in plantar flexion, adduction, supination and varus. The deformity does not affect only the foot position, which is usually investigated by radiography, CT, micro-CT, MRI or ultrasound but logically influence the whole gait biomechanics. It is supposed, that clubfoot belongs to a group of fibroproliferative disorders whose origin and multi- hierarchical effect remain unknown. It has been suggested that fibroblasts and growth factors may be involved. To gain a more global view, direct analysis of the protein composition of extra cellular matrix, a proteomic approach was used. At present two principle methods are mostly used for the treatment of clubfoot: physiotherapy and the Ponseti method. The determination of the general biological and biomechanical parameters for various regio ns of the clubfoot can potentially help in the understanding of the mechanisms participating on this serious anomaly and thus contribute to the development of the more efficient therapeutic approach. This review summarizes the present knowledge on the poss ible pathogenetic mechanisms participating in the development of the clubfoot and their possible relation to the new therapeutic approaches., M. Ošťádal, J. Lišková, D. Hadraba, A. Eckhardt., and Obsahuje bibliografii
Summary Mitochondria are exposed to reactive nitrogen species under physiological conditions and even more under several pathologic states. In order to reveal the mechanism of these processes we studied the effects of peroxynitrite on isolated beef heart mitochondria in vitro. Peroxynitrite has the potential to nitrate protein tyrosine moieties, break the peptide bond, and eventually release the membrane proteins into the solution. All these effects were found in our experiments. Mitochondrial proteins were resolved by 2D electrophoresis and the protein nitration was detected by immunochemical methods and by nano LC-MS/MS. Mass spectrometry confirmed nitration of ATP synthase subunit beta, pyruvate dehydrogenase E1 component subunit beta, citrate synthase and acetyl-CoA acetyltransferase. Immunoblot detection using chemiluminiscence showed possible nitration of other proteins such as cytochrome b-c1 complex subunit 1, NADH dehydrogenase [ubiquinone] ironsulfur protein 2, elongation factor Tu, NADH dehydrogenase [ubiquinone] flavoprotein 2, heat shock protein beta-1 and NADH dehydrogenase [ubiquinone] iron-sulfur protein 8. ATP synthase beta subunit was nitrated both in membrane and in fraction prepared by osmotic lysis. The high sensitivity of proteins to nitration by peroxynitrite is of potential biological importance, as these enzymes are involved in various pathways associated with energy production in the heart., M. Kohutiar, A. Eckhardt, I. Mikšík, P. Šantorová, J. Wilhelm., and Seznam literatury