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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Obesity and the metabolic syndrome have hepatic manifestations, including steatosis and progression of fibrosis. In individuals with chronic hepatitis C, obesity is associated with inflammation, insulin resistance, steatosis, progression of fibrosis, and nonresponse to treatment with interferon or peginterferon alpha and ribavirin. Patients with both hepatitis C and obesity-related nonalcoholic fatty liver disease are at greater risk for more advanced liver disease. We review the mechanisms by which obesity may be associated with decreased efficacy of interferon-based therapies in individuals with chronic hepatitis C and the therapeutic strategies that may increase the effectiveness of these therapies in obese individuals.
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PMID:Impact of obesity on treatment of chronic hepatitis C. 1672 27

Among "patients difficult to treat" there are infected with genotypes 1,4 HCV, patients with liver cirrhosis, blacks, immunocompromised, hemodialyzed and non-responders to previous treatment. Multicenter, randomized trials were confirmed lower sustained virologic response (SVR) in patients infected with genotype 1 HCV. To improve the response longer therapy during 72 weeks was suggested. In genotype 4 HCV infected relationship of therapeutic efficacy with patients ethnicity was shown. The standard of HCV therapy in HIV infected patients is combined therapy with pegylated interferon and ribavirin. This therapy depends of the advance of HIV infection and administered antiretroviral therapy. Pharmacokinetic examination of safety and tolerability of pegylated interferon in patients with renal insufficiency was revealed the base to administering it in these patients. Controversial in this group is administering of ribavirin. Relationships between body weight, body mass index, obesity, liver steatosis, insulin resistance and therapeutic response in patients with chronic hepatitius C are analyzed. Trials assessed the efficacy of retherapy with pegylated interferon and ribavirin patients, who non responded to previous therapy revealed positive results.
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PMID:[Chronic hepatitis C--patients "difficult to treat"]. 1675 48

Insulin resistance is more often seen in hepatitis C than in other liver diseases, including non-alcoholic steatohepatitis. The Homeostasis Model for Assessment [HOMA= fasting insulin (mUI/ml) * fasting glucose (mmol/L) / 22.5] has proved useful in the measurement of insulin sensitivity in euglycemic patients. Cross-sectional and case-cohort studies support a role for hepatitis C as a factor implied in the development of type-2 diabetes in high-risk patients (male patients, older than 40 years, and overweight). In transgenic mice models the HCV core protein has been found to induce insulin resistance via TNF production. Insulin resistance has been associated with steatosis development and fibrosis progression in a genotype-dependent manner. In genotype-1 patients, the mechanisms by which insulin resistance promotes fibrosis progression include: a) steatosis; b) hyperleptinemia; c) increased TNF production; and d) impaired expression of PPARg receptors. Indeed, insulin resistance has been found as a common denominator to the majority of features associated with difficult-to-treat patients. Patients with cirrhosis, obesity, coinfected with HIV, and Afro-American, all of them showed insulin resistance. Insulin resistance strongly influences sustained response rates, at least in genotype-1 patients. Insulin resistance decreases during and after treatment in patients that achieved virus C clearance. Moreover, the incidence of type-2 diabetes seems to be lower in responders than in non-responders. In summary, hepatitis C promotes insulin resistance and insulin resistance induces steatosis, fibrosis, and interferon resistance. The treatment of insulin resistance by decreasing hyperinsulinemia could improve sustained response rates in patients with chronic hepatitis C treated with peginterferon plus ribavirin.
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PMID:Hepatitis C and insulin resistance: steatosis, fibrosis and non-response. 1704 97

Interleukin (IL)-18 is a proinflammatory cytokine that plays an important role in both innate and adaptive immune responses against viruses and intracellular pathogens. Increased levels of circulating IL-18 from HIV-1 infected patients have been reported especially in the advanced and late stages of the disease, whereas in the initial stage serum levels of IL-18 were not increased. In contrast, low production of Il-18 was observed in vitro from peripheral blood mononuclear cells (PBMC) of HIV-1 infected patients, and these results were also observed in macaques infected with simian immunodeficiency virus (SIV). In addition, decreased IL-18 production from PBMC was significantly correlated with low production of IL-2. Furthermore, serum levels of IL-18 significantly decreased after highly active antiretroviral therapy. During the early stage of HIV-1 infection there is a decreased production of gamma interferon (IFN), IL-12 and IL-2 as well as not activation of IL-18 production and this leads to inhibition of Th1 immune response, whereas in the advanced stage of the disease, strong activation of IL-18 production along with persistent decreased production of gamma IFN, IL-12 and IL-2 may promote a Th2 immune response, which leads to persistent viral replication. Several studies have shown increased levels of IL-18 in HIV-seronegative subjects with obesity, insulin resistance and type II diabetes. Metabolic disorders, fat redistribution and cardiovascular manifestations are becoming more frequent in HIV-1 infected patients treated with antiretroviral drugs. Consequently, involvement of IL-18 in these disorders has been postulated and demonstrated in patients with lipodistrophy, or with hypertriglyceridemia. Finally, higher serum levels of IL-18 may represent an useful marker in HIV-1 infected patients with metabolic disorders and fat redistribution, as well as a sensitive predictor of cardiovascular complications in treated patients.
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PMID:Interleukin-18: a proinflammatory cytokine in HIV-1 infection. 1707 17

Adiponectin and, especially, its oligomeric complex composition have been suggested to be critical in determining insulin sensitivity. Pro-inflammatory cytokines play an important role in the development of insulin resistance in obesity and associated diseases. Therefore, we investigated the effect of long-term exposure of tumour necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-1beta, and interferon (IFN)-gamma on total insulin-sensitizing adiponectin secretion and adiponectin complex formation from human adipocytes. In parallel, adipocyte delipidation and leptin production levels were monitored. The present study demonstrates that TNF-alpha, IL-1beta, and IFN-gamma dose and time dependently suppressed total adiponectin secretion within 7 days (60, 70, and 35% reduction respectively). IL-6 was also able to reduce (50%) adiponectin production, although only in combination with exogenous soluble IL-6 receptors (sIL-6R). However, the oligomeric distribution (high, middle, and low molecular weight (HMW) complexes) of secreted adiponectin was not altered by any of these cytokines. All studied pro-inflammatory cytokines resulted in delipidation and reduction of lipid-laden adipocyte numbers. Despite this reduction of lipid-laden adipocytes, TNF-alpha, IL-6/sIL-6R, and IL-1beta stimulated leptin release. Our data indicate that (i) long-term pro-inflammatory cytokine exposure downregulates total adiponectin secretion from delipidizing adipocytes and (ii) pro-inflammatory cytokines are not important regulators of adipocyte-derived adiponectin oligomerization. Hence, their individual contribution to low expression of HMW adiponectin found in insulin-resistant conditions seems unlikely. Furthermore, delipidizing adipocytes and preadipocytes are active leptin producers when stimulated by TNF-alpha, IL-6/sIL-6R, and IL-1beta.
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PMID:Pro-inflammatory delipidizing cytokines reduce adiponectin secretion from human adipocytes without affecting adiponectin oligomerization. 1728 29

Obese individuals often have low plasma adiponectin and concomitant chronic inflammation with a predisposition to metabolic and cardiovascular diseases. The present study reports a novel antiinflammatory action of adiponectin in human monocyte-derived macrophages (MPhi) suppressing T-lymphocyte accumulation in atherogenesis. RNA profiling of lipopolysaccharide-stimulated human MPhi identified CXC chemokine ligands (CXCLs), such as IP-10 (interferon [IFN]-inducible protein 10) (CXCL10), I-TAC (IFN-inducible T-cell alpha chemoattractant) (CXCL11), and Mig (monokine induced by IFN-gamma) (CXCL9), T-lymphocyte chemoattractants associated with atherogenesis, among the top 14 transcripts suppressed by adiponectin. Real-time quantitative RT-PCR and ELISA verified that adiponectin inhibited expression of these chemokines at both the mRNA and protein levels in a concentration-dependent manner. Adiponectin reduced the release by lipopolysaccharide-stimulated MPhi of chemoattractant activity for CXC chemokine receptor 3-transfected (receptor for IP-10, Mig, and I-TAC) lymphocytes. Adiponectin decreased lipopolysaccharide-inducible IP-10 promoter activity in promoter-transfected THP-1 MPhi but did not change IP-10 mRNA stability. In lipopolysaccharide-stimulated MPhi, reduction of IFN-beta by adiponectin preceded inhibition of IP-10 mRNA expression. Immunoblot and chromatin immunoprecipitation analyses demonstrated that adiponectin attenuated activation of the transcription factor IFN regulatory factor 3, involved in the MyD88-independent pathway of Toll-like receptor 4 signaling, and subsequent IFN regulatory factor 3 binding to IFN-beta promoter. In vivo studies further demonstrated that apolipoprotein E/adiponectin double-deficient (apoE-/-APN-/-) mice had increased plasma IP-10 levels, accelerated T-lymphocyte accumulation in atheromata, and augmented atherogenesis compared with apoE single-deficient (apoE-/-APN+/+) mice. This study establishes that low levels of adiponectin associated with obesity, the metabolic syndrome, and diabetes favor T-lymphocyte recruitment and contribute to adaptive immune response during atherogenesis.
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PMID:Adiponectin inhibits the production of CXC receptor 3 chemokine ligands in macrophages and reduces T-lymphocyte recruitment in atherogenesis. 1823 40

Obstructive sleep apnea (OSA), often concomitant with obesity, increases the risk for the metabolic syndrome. One mechanism that may participate in this association is upregulation of inflammatory pathways. We used structural equation modeling to assess the interrelations between childhood obesity, OSA, inflammation, and metabolic dysfunction. One hundred and eighty-four children (127 boys, mean age: 8.5 +/- 4.1 years) had height and weight measured, underwent overnight polysomnography and had fasting blood taken. The blood was analyzed for insulin, glucose, lipids, leptin, and cytokines [interferon (IFN)-gamma, granulocyte macrophage-colony stimulating factor, interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, tumor necrosis factor-alpha]. Structural equation modeling (SEM) was used to evaluate associations between the outcomes of interest including hypoxia, arousal (related to respiratory and spontaneous), obesity, metabolic dysfunction, and inflammatory markers. Two cytokine factors and one metabolic factor were derived for the SEM. These factors provided good fit in the structural equation model (chi(2)/df = 2.855; comparative fit index = 0.90, root mean squared error of approximation = 0.10) and all factor loadings were significantly different from zero (P < or = 0.01). Overall, our results indicate that while obesity (as measured by body mass index z-score) has a major influence on the metabolic dysfunction associated with OSA, arousal indices, and cytokine markers may also influence this association. Our results support the hypothesis that OSA is a contributor to the mechanisms that link sleep, systemic inflammation and insulin resistance, and show that the interrelations may begin in childhood.
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PMID:Structural equation modeling of sleep apnea, inflammation, and metabolic dysfunction in children. 1803 84

Chronic Hepatitis C (CHC) and obesity inflict significant health and economic burdens on the world. A complex interplay between these conditions results in the ultimate phenotype of liver disease. Taking into consideration the increasing prevalence of obesity in patients with CHC and the decreasing rate of sustained virologic response (SVR), it would be advantageous to identify potential therapeutic strategy to improve liver histology and responsiveness to antiviral therapy. The adipokines-leptin, adiponectin, TNF-alpha-, which are modified in obesity, have been proposed as determinant factors of non-responsiveness to the IFN-alpha/Ribavirin treatment and of liver fibrosis extension in patients with CHC and obesity. Weight loss and long-term maintenance of optimal weight resulted in a sustained improvement in hepatic fibrosis and an increased rate of SVR in obese patients with CHC. The ability to exert antiviral activities and the anti-obesity effect of omega-3 PUFA provide a good basis for clinical use of these very interesting nutrients, both as dietary components and as future drugs with potentially beneficial effects and few side effects. We reviewed the mechanisms underlying the correlation of obesity with the nonresponsiveness to antiviral therapy and with fibrosis extension in CHC, and the mechanisms by which PUFA omega-3 may be associated with an increased efficacy of interferon-based therapies and an antifibrogenic effect in obese individuals with CHC.
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PMID:Impact of obesity and omega-3 polyunsaturated fatty acids on fibrogenesis and responsiveness to antiviral therapy in chronic hepatitis C. 1833 70

Insulin resistance is extremely common and frequently is associated with comorbid conditions such as cardiovascular disease, hypertension, obesity, infertility, and neurodegeneration. In addition, insulin resistance is the driving force for type 2 diabetes mellitus. Interestingly, co-existence of insulin resistance and chronic hepatitis C occurs more often than predicted by chance, with recent estimates indicating that 30% to 70% of patients with chronic hepatitis C display some evidence of insulin resistance. Recent research revealed several molecules, including tumor necrosis factor alpha, suppressor of cytokine signaling 1 and 3 proteins, insulin-receptor substrates 1 and 2, and other adipocytokines, potentially are involved in the development of insulin resistance in patients with chronic hepatitis C. Unfortunately, baseline insulin resistance has a negative impact on treatment outcomes in patients with chronic hepatitis C. However, successfully managing insulin resistance or diabetes mellitus in these patients may improve patients' likelihoods of successful outcomes with antiviral therapy. Likewise, eradication of hepatitis C virus in patients with insulin resistance or diabetes mellitus appears to improve glucose metabolism. Although adjunctive therapies such as insulin sensitizers and weight loss often are recommended, their ability to improve antiviral treatment response in patients with chronic hepatitis C is unproven. Studies are under way to determine whether improving insulin sensitivity results in better outcomes in patients receiving pegylated interferon alfa plus ribavirin therapy for chronic hepatitis C.
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PMID:Insulin resistance among patients with chronic hepatitis C: etiology and impact on treatment. 1858 70

Emerging attention has been paid to metabolic syndrome, which comprises several metabolic disorders including visceral obesity, diabetes mellitus, dyslipidemia, and hypertension. Whether the severity of each disease is mild to moderate, the comorbidity of these metabolic disorders has a serious impact on the development of atherosclerosis. Nonalcoholic fatty liver disease (NAFLD) is the major hepatic disorder in patients with metabolic syndrome, and indeed it is the most common cause of abnormal liver function tests in the working population in industrialized countries. In recent years, it has become recognized that NAFLD is no longer just a trivial disease, and a rather considerable proportion of the patients develop liver cirrhosis. Furthermore, chronic infection of hepatitis C virus also develops a pathological feature of steatohepatitis, and extended hepatic steatosis has a serious impact not only on the progression of hepatic fibrosis but also on the antiviral efficacy of interferon therapy. Emerging lines of studies indicated that insulin resistance, abnormal lipid metabolism, and dysregulation of cytokines/adipokines (e.g., tumor necrosis factor-alpha, adiponectin, and leptin) are profoundly involved in the pathogenesis of NAFLD. This review aims to integrate the reported evidence and to provide the current point of view for comprehensive understanding of the pathophysiology of steatohepatitis.
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PMID:Liver diseases and metabolic syndrome. 1864 37


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