It is now generally accepted that adipose tissue acts as an endocrine organ producing a number of substances with an important role in the regulation of food intake, energy expenditure and a series of metabolic processes. Adiponectin is a recently discovered protein produced exclusively by adipocytes. A number of studies have shown that obesity, insulin resistance and atherosclerosis are accompanied by decreased adiponectin levels and that adiponectin replacement under experimental settings is able to diminish both insulin resistance and atherosclerosis. The aim of this review is to summarize the current knowledge about the physiology and pathophysiology of adiponectin and to discuss its potential in the treatment of insulin resistance and atherosclerosis.
Genes for adiponectin and resistin are candidate genes of insulin resistance and type 2 diabetes mellitus. The aim of our study was to determine the frequency of single nucleotide polymorphisms (SNP) 45T>G and 276G>T of the adiponectin gene and 62G>A and -180C>G of the resistin gene in patients with obesity (OB), anorexia nervosa (AN) and in control healthy normal-weight women (NW) and to study the influence of particular genotypes on serum concentrations of these hormones and on insulin sensitivity. Serum adiponectin, resistin, tumor necrosis factor alpha (TNF-alpha), insulin, cholesterol, glycated hemoglobin (HbA1c) and blood glucose levels were measured in 77 patients with OB, 28 with AN and 38 NW. DNA analysis was carried out by polymerase chain reaction with restriction analysis of PCR product. The presence of SNP ADP+276 G>T allele was accompanied by higher cholesterol levels in AN patients, higher adiponectin concentrations in OB patients and lower HbA1c levels in NW. SNP of the resistin gene 62G>A was associated with lower HbA1c in NW and higher cholesterol concentrations in OB group. The carriers of the minor G allele in the position -180 of the resistin gene within AN group had significantly higher BMI relative to non-carriers. We conclude that polymorphisms in adiponectin and resistin genes can contribute to metabolic phenotype of patients with obesity and anorexia nervosa., J. Křížová, M. Dolinková, Z. Lacinová, Š. Sulek, R. Doležalová, J. Housová, J. Krajíčková, D. Haluzíková, L. Bošanská, H. Papežová, M. Haluzík., and Obsahuje bibliografii a bibliografické odkazy
Serum levels of adiponectin were measured in patients with benign prostatic hyperplasia and prostate cancer of pT2 and pT3 stage. Adiponectin ELISA assay, immunohistochemistry, and selected metabolic and biochemical parameters measurement was performed in 25 patients with benign prostatic hyperplasia and 43 with prostate cancer (17 patients with organ-confined and 26 patients with locally advanced disease). Serum adiponectin levels did not differ between prostate benign hyperplasia and cancer clinical stage T2, but was significantly higher in pT3 relative to pT2 group (14.51± 4.92 vs. 21.41±8. 12, P = 0.003). Tissue immunohistochemistry showed enhanced staining in neoplastic prostate glands and intraepithelial neoplasia relative to benign prostatic hyperplasia without distinction between disease grade and stage. Serum adiponectin levels are higher in locally advanced relative to organ-confined prostate cancer and may thus serve as an auxiliary marker providing further improvement for discrimination between pT2 and pT3 stages., D. Housa, Z. Vernerová, J. Heráček, B. Procházka, P. Čechák, J. Kuncová, M. Haluzík., and Obsahuje bibliografii a bibliografické odkazy
Adiponectin acts as an endogenous antithrombotic factor. However, the mechanisms underlying the inhibition of platelet aggregation by adiponectin still remain elusive. The present study was designed to test whether adiponectin inhibits platelet aggregation by attenuation of oxidative/nitrative stress. Adult rats were fed a regular or high-fat diet for 14 weeks. The platelet was immediately separated and stimulated with recombinant full-length adiponectin (rAPN) or not. The platelet aggregation, nitric oxide (NO) and superoxide production, endothelial nitric oxide synthase (eNOS)/inducible NOS (iNOS) expression, and antioxidant capacity were determined. Treatment with rAPN inhibited hyperlipidemia- induced platelet aggregation (P<0.05). Interestingly, total NO, a crucial molecule depressing platelet aggregation and thrombus formation , was significantly reduced, rather than increased in rAPN-treated platelets. Treatment with rAPN markedly decreased superoxide production (-62 %, P<0.05) and enhanced antioxidant capacity (+38 %, P<0.05) in hyperlipidemic platelets. Hyperlipidemia-induced reduced eNOS phosphorylation and increased iNOS expression were significantly reversed following rAPN treatment (P<0.05, P<0.01, respectively). Taken together, these data suggest that adiponectin is an adipokine that suppresses platelet aggregation by enhancing eNOS activation and attenuating oxidative/nitrative stress including blocking iNOS expression and superoxide production., W.-Q. Wang ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
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
Adipose tissue is a hormonally active tissue, producing adipocytokines which may influence activity of other tissues. Adiponectin, abundantly present in the plasma increases insulin sensitivity by stimulating fatty acid oxidation, decreases plasma triglycerides and improves glucose metabolism. Adiponectin levels are inversely related to the degree of adiposity. Anorexia nervosa and type 1 diabetes are associated with increased plasma adiponectin levels and higher insulin sensitivity. Decreased plasma adiponectin levels were reported in insulin-resistant states, such as obesity and type 2 diabetes and in patients with coronary artery disease.Activity of adiponectin is associated with leptin, resistin and with steroid and thyroid hormones, glucocorticoids, NO and others.
Adiponectin suppresses expression of extracellular matrix adhesive proteins in endothelial cells and atherosclerosis potentiating cytokines. Anti-atherogenic and anti-inflammatory properties of adiponectin and the ability to stimulate insulin sensitivity have made adiponectin an important object for physiological and pathophysiological studies with the aim of potential therapeutic applications.
Adiponektin je hormon tukové tkáně, který je přítomen v krvi v poměrně vysokých koncentracích. Působí jako protektivní faktor při iniciaci a progresi aterosklerózy díky svým protizánětlivým a protiaterogenním vlastnostem. Jeho sérové hladiny jsou sníženy u obézních jedinců, pacientů s diabetem 2. typu, u pacientů s onemocněním koronárních arterií atd. Hladina adiponektinu pozitivně koreluje s hladinou HDL cholesterolu, negativně naopak s markery zánětu, inzulinové rezistence, triacylglyceroly a markery metabolismu na triacylglyceroly bohatých lipoproteinových částic, a dalšími adipokiny. Adiponektin působí jako ochranný faktor v rozvoji onemocnění spojených s obezitou. Protizánětlivý efekt může být hlavní složkou jeho kladného působení při potlačování kardiovaskulárních a metabolických onemocnění včetně aterosklerózy a inzulinové rezistence. Navíc se zdá, že vykazuje přímou biologickou aktivitu, a to mj. indukcí klasické cesty aktivace komplementu. Gen pro adiponektin je polymorfní a v jeho blízkosti leží také susceptibilní lokusy pro DM 2. typu a metabolický syndrom. Tato přehledná práce se zabývá adiponektinem a jeho vztahem k ateroskleróze, popisuje některé polymorfi smy na genu pro adiponektin a všímá si jeho protizánětlivého účinku., Adiponectin is an adipose tissue-derived hormone which circulates at relatively high concentrations in blood. Adiponectin has protective actions in the initiation and progression of atherosclerosis through anti-infl ammatory and anti-atherogenic effects. Adiponectin serum levels are decreased in obesity, type 2 diabetes, and patients with coronary artery disease, etc. The level of circulating adiponectin correlates positively with HDL cholesterol, and negatively with infl ammatory markers, markers of insulin resistance, triglyceride-rich lipoprotein particles, and other adipokines. Adiponectin displays protective actions on development of various obesity-linked diseases. The anti-infl ammatory properties may be the major component of its benefi cial effects on cardiovascular and metabolic disorders including atherosclerosis and insulin resistance. In addition, adiponectin displays a direct biological activity through the induction of a classical pathway of complement activation. The polymorphic gene for adiponectin is located in the close proximity of susceptibility loci for type 2 diabetes and metabolic syndrome. This review deals with adiponectin and its relationship to atherosclerosis, describes some adiponectin gene polymorphisms and focuses on its anti-infl ammatory effects., Novotný Dalibor, Vaverková H., Karásek D., Halenka M., and Lit.: 28
Obezita je v kombinaci s dalšími složkami syndromu inzulinové rezistence výrazným rizikovým faktorem aterosklerózy a jejich komplikací. Přesné mechanizmy propojení uvedených onemocnění jsou dosud objasněny pouze zčásti. Jedním z možných pojítek je porucha endokrinní funkce tukové tkáně, která při obezitě produkuje zvýšené množství prozánětlivých a proaterogenních hormonů a cytokinů a méně faktorů protektivních. Prakticky jediným z hormonů tukové tkáně s prokázaným protizánětlivým a antiaterosklerotickým účinkem je hormon adiponektin. Tento hormon je produkován převážně adipocyty a jeho hladiny jsou sníženy právě u pacientů s obezitou, inzulinovou rezistencí a aterosklerózou. Cílem tohoto článku je shrnout současné experimentální a klinické poznatky o vztahu adiponektinu k ateroskleróze a diskutovat možné využití tohoto hormonu v predikci aterosklerózy a případné perspektivy jeho využití v prevenci a léčbě tohoto onemocnění., Denisa Haluzíková, T. Roubíček, Martin Haluzík, and Lit. 39
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