Adiponectin is an adipokine increasing glucose and fatty acid metabolism and improving insulin sensitivity. The aim of this study was to investigate the role of adiponectin in the regulation of adipocyte lipolysis. Human adipocytes isolated from biopsies obtained during surgical operations from 16 non-obese and 17 obese subjects were incubated with 1) human adiponectin (20 μg/ml) or 2) 0.5 mM AICAR - activator of AMPK (adenosine monophosphate activated protein kinase). Following these incubations, isoprenaline was added (10-6 M) to investigate the influence of adiponectin and AICAR on catecholamine-induced lipolysis. Glycerol concentration was measured as lipolysis marker. We observed that adiponectin suppressed spontaneous lipolysis by 21 % and isoprenaline-induced lipolysis by 14 % in non-obese subjects. These effects were not detectable in obese individuals, but statistically significant differences in the effect of adiponectin between ob ese and non-obese were not revealed by two way ANOVA test. The inhibitory effect of AICAR and adiponectin on lipolysis was reversed by Compound C. Our results suggest, that adiponectin in physiological concentrations inhibits spontaneous as well as catecholamine-induced lipolysis. This effect might be lower in obese individuals and this regulation seems to involve AMPK., Z. Wedellová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
High -energy intake which exceeds energy expenditure leads to the accumulation of triglycerides in adipose tissue, predominantly in large -size adipocytes. This metabolic shift, which drives the liver to produce atherogenic dyslipidemia, is well documented. In addition, an increasing amount of monocytes/macrophages, predominantly the proinflammatory M1- type, cumulates in ectopic adipose tissue. The mechanism of this process, the turnover of macrophages in adipose tissue and their direct atherogenic effects all remain to be analyzed., R. Poledne, I. Králová Lesná, S. Čejková., and Obsahuje bibliografii
We investigated the effects of telmisartan, the blocker of angiotensin II receptor 1, on the regulation of systolic blood pressure (SBP) and oxidative stress through endothelial nitric oxide (NO) release in spontaneously hypertensive rats (SHRs). SHRs randomly received placebo, oral feeding of telmisartan (5 mg/kg or 10 mg/kg) every day and Wistar-Kyoto rats (WKYs) served as normotensive control. The SBP of rat was measured before and weekly thereafter. After a total of 8-week treatment, rats were killed for experimental measurements. Parameters that subject to measurements in isolated aorta endothelial cells include: NO concentration, protein expression levels of angiotensin II receptor 1, nitrotyrosine, 8-isoprostane, SOD, PI3K, Akt, AMPK and eNOS. In addition, L-NMMA, a general inhibitor of nitric oxide synthase, was also applied to test the inhibition of NO concentration. We found that SBPs were significantly lower in telmisartan therapy group than in placebo treated hypertensive rats and WKYs (p<0.05). The NO concentration was significantly higher in telmisartan-treated group with increased activity of the PI3K/Akt pathway and activated eNOS signaling. Blockade of Akt activity reversed such effects. Activation of AMPK also contributed to the phosphorylation of eNOS. L-NMMA treatment reduced less NO concentration in SHR rats than the telmisartan co-treated groups. Oxidative stress in SHRs was also attenuated by telmisartan administration, shown by reduced formation of nitrotyrosine, 8-isoprostane, and recovered SOD protein level. Telmisartan enhanced NO release by activating the PI3K/Akt system, AMPK phosphorylation and eNOS expression, which attenuated the blood pressure and oxidative stress in SHRs., L. Xu, Y. Liu., and Obsahuje seznam literatury
The function of adult neurogenesis in the dentate gyrus is not yet completely understood, though many competing theories have attempted to explain the function of these newly -generated neurons. Most theories give adult neurogenesis a role in aiding known hippocampal/dentate gyrus functions. Other theories offer a novel role for these new cells based on their unique physiological qualities, such as their low excitability threshold. Many behavioral tests have been used to test these theories, but results have been inconsistent and often contradictory. Substantial variability in tests and protocols may be at least partially responsible for the mixed results. On the other hand, conflicting results arising from the same tests can serve as aids in elucidating the function of adult neurogenesis. Here, we offer a hypothesis that considers the cognitive nature of tasks commonly used to assess the function of adult neurogenesis, and introduce a dichotomy between tasks focused on discrimination vs. generalization. We view these two aspects as opposite ends of the continuous spectrum onto which traditional tests can be mapped. We propose that high neurogenesis favors behavioral discrimination while low adult neurogenesis favors behavioral generalization of a knowledge or rule. Since many tasks require both, the effects of neurogenesis could be cancelled out in many cases. Although speculative, we hope that our view presents an interesting and testable hypothesis of the effect of adult neurogenesis in traditional behavioral tasks. We conclude that new, carefully designed behavioral tests may be necessary to reach a final consensus on the role of adult neurogenesis in behavior., A. Pistikova, H. Brozka, A. Stuchlik., and Obsahuje bibliografii
Advanced glycation end products (AGEs) may play an important adverse role in process of atherosclerosis, diabetes, aging and chronic renal failure. Levels of Ne-carboxymethyllysine and fluorescent AGE values were estimated in two nutritional population groups - alternative group (vegetarians - plant food, milk products, eggs) and traditional group (omnivorous subjects). Vegetarians have a significantly higher carboxymethyllysine content in plasma and fluorescent AGE values. Intake of proteins, lysine and monosaccharides as well as culinary treatment, consumption of food AGEs (mainly from technologically processed products) and the routes of Maillard reaction in organism are the substantial sources of plasma AGEs. Vegetarians consume less proteins and saccharides. Lysine intake is significantly reduced (low content in plant proteins). Subjects on alternative nutrition do not use high temperature for culinary treatment and consume low amount of technologically processed food. Fructation induced AGE fluorescence is greater as compared with that induced by glucose. It is due to higher participation of a more reactive acyclic form of fructose. Intake of vegetables and fruit with predominance of fructose is significantly higher in vegetarians. Comparison of nutrition and plasma AGEs in vegetarian and omnivorous groups shows that the higher intake of fructose in alternative nutrition of healthy subjects may cause an increase of AGE levels., M. Krajčovičová-Kudláčková, K. Šebeková, R. Schinzel., 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
Advanced glycation end-product (AGE) pentosidine has previously been demonstrated in different tissues and body fluids. It was suggested as a novel marker for evaluating the pathologic activity in rheumatoid arthritis (RA). In this study we analyzed the relation between pentosidine and markers of inflammation, cartilage turnover, immune response, and disease status of RA. Using HPLC, we analyzed pentosidine in serum and synovial fluid from 39 patients with RA and in serum from 38 healthy controls. Cartilage oligomeric matrix protein (COMP) and antibodies to CCP (anti-CCP) were measured by ELISA. Clinical disease status was assessed by Disease Activity Score 28 (DAS 28) and functional status by Health Assessment Questionnaire (HAQ). We demonstrated significantly higher serum levels of pentosidine in RA patients in comparison with controls. Pentosidine in serum significantly correlated with pentosidine in synovial fluid. Serum pentosidine levels were associated with erythrocyte sedimentation rate (p<0.03) but not with CRP, COMP, anti-CCP antibodies, DAS 28, or HAQ. In contrast to previous studies, we could not show any correlation of pentosidine levels with inflammatory status, clinical disease activity, markers of immune response, or cartilage breakdown. However, AGEs can be suggested as important players participating in joint destruction rather than markers of disease activity., L. Šenolt, M. Braun, J. Vencovský, L. Šedová, K. Pavelka., and Obsahuje bibliografii a bibliografické odkazy
Accelerated glycoxidation takes part in the development of diabetic complications. We determined advanced glycation end-products (AGEs) and advanced oxidation protein products (AOPP) in the sera of 52 patients with diabetes mellitus (DM) - 18 with DM Type 1 and 34 with DM Type 2 and examined their relationship to the compensation of the disease. AGEs were estimated spectrofluorimetrically (350 nm/440 nm) whereas AOPP were determined spectro-photometrically (340 nm). AGEs were elevated only in DM Type 2 (DM2 5.11±1.15x103 AU/g vs controls 4.08±0.71x103 AU/g, p<0.001, vs DM1 4.14±0.86x103 AU/g, p<0.005, DM1 vs controls were not significant). AOPP were elevated significantly in both types of DM with higher levels in DM Type 2 (DM2 157.50±75.15 mmol/l vs healthy subjects 79.80±23.72 mmol/l, p<0.001, vs DM1 97.50±30.91 mmol/l, p<0.005, DM1 vs controls p<0.05). There was a tight correlation between AGEs and AOPP in both types of DM (DM1 r=0.75, DM2 r=0.47 (p<0.05)) and both AGEs and AOPP correlated with triglycerides. In DM Type 1 only, AGEs correlated with HbA1c r=0.47 (p<0.05) and with blood glucose. Slight but not significant differences in AGEs and AOPP levels were observed in patients with or without diabetic complications. Oxidative stress is increased in both types of DM, more in Type 2 where it contributes to the formation of glycoxidation products., M. Kalousová, J. Škrha, T. Zima., and Obsahuje bibliografii
It has been shown that besides positron emission tomography, single photon emission computed tomography and magnetic resonance imaging; contrast echocardiography can be used for qualitative and quantitative myocardial perfusion assessment. In this review, the properties of ultrasound contrast agents, imaging techniques and acquisition methods are shortly described and the possibilities of perfusion echocardiography are summarized. The main focus is put on the description of three perfusion models: mathematical models, physical models assuming an ideal inflow and physical models including inflow measurement., R. Kolář ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
AMP -activated protein kinase (AMPK) plays a role in metabolic regulation under stress conditions, and inadequate AMPK signaling may be also involved in aging process. The aim was to find out whether AMPK α 2-subunit deletion affects heart function and ische mic tolerance of adult and aged mice. AMPK α 2 -/- (KO) and wild type (WT) female mice were compared at the age of 6 and 18 months. KO mice exhibited subtle myocardial AMPK α 2-subunit protein level, but no difference in AMPK α 1-subunit was detected between the strains. Both α 1- and α 2-subunits of AMPK and their phosphorylation decreased with advanced age. Left ventricular fractional shortening was lower in KO than in WT mice of both age groups and this difference was maintained after high-fat feeding. Infarct size induced by global ischemia/reperfusion of isolated hearts was similar in both strains at 6 months of age. Aged WT but not KO mice exhibited improved ischemic tolerance compared with the younger group. High-fat feeding for 6 months during aging abolished the infarct size-reduction in WT without affecting KO animals; nevertheless, the extent of injury remained larger in KO mice. The results demonstrate that adverse effects of AMPK α 2-subunit deletion and high-fat feeding on heart function and myocardia l ischemic tolerance in aged female mice are not additive., K. Slámová, F. Papoušek, P. Janovská, J. Kopecký, F. Kolář., and Obsahuje bibliografii