Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study examines the role of thyroid cell injury in the initiation of autoimmune thyroiditis by iodine in Obese strain (OS) chickens, a strain genetically susceptible to spontaneous autoimmune thyroiditis. OS and normal strain chickens were placed on an iodine depletion regimen started in ovo. This regimen is known to prevent thyroiditis in OS chickens. The chickens were injected with NaI every 24 h for up to 7 days starting at 3 weeks of age. Both strains showed evidence of mild thyrocyte injury 12 h after NaI. However, significant and sustained infiltration, beginning 24 h after NaI, was seen only in the OS. The infiltrating cells were primarily mononuclear. Polymorphonuclear cells were not observed. Immunohistological analysis showed the infiltrate to be composed of CD8 T cells, CD4 T cells, B cells, and macrophages in the ratio 40:20:22:17. The infiltration was sustained and progressive for at least 7 days. Thyroid infiltration after NaI repletion was significantly reduced in OS chickens tolerized to thyroglobulin at hatching. Prior treatment with the antioxidant drug ethoxyquin completely prevented both the thyrocyte injury and the infiltration induced by iodine. Treatment with antioxidant drugs had no effect on the uptake and incorporation of iodine by the thyroid. In summary, 1) iodine caused thyrocyte injury in both OS and normal chickens. 2) The injury was followed by cellular infiltration in the OS but not in normal chickens. 3) The infiltration appeared to be immune mediated in being primarily lymphocytic and at least partially thyroglobulin sensitive. 4) Prevention of thyroid injury by antioxidant drug treatment also prevented infiltration. We conclude that thyroid cell injury may be an initial event in the induction of autoimmune thyroiditis by iodine.
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PMID:Thyroid cell injury is an initial event in the induction of autoimmune thyroiditis by iodine in obese strain chickens. 758 41

Thanks to progress in zinc research, it is now possible to describe in more detail how zinc ions (Zn++) and nitrogen monoxide (NO), together with glutathione (GSH) and its oxidized form, GSSG, help to regulate immune responses to antigens. NO appears to be able to liberate Zn++ from metallothionein (MT), an intracellular storage molecule for metal ions such as zinc (Zn++) and copper (Cu++). Both Zn++ and Cu++ show a concentration-dependent inactivation of a protease essential for the proliferation of the AIDS virus HIV-1, while zinc can help prevent diabetes complications through its intracellular activation of the enzyme sorbitol dehydrogenase (SDH). A Zn++ deficiency can lead to a premature transition from efficient Th1-dependent cellular antiviral immune functions to Th2-dependent humoral immune functions. Deficiencies of Zn++, NO and/or GSH shift the Th1/Th2 balance towards Th2, as do deficiencies of any of the essential nutrients (ENs) - a group that includes methionine, cysteine, arginine, vitamins A, B, C and E, zinc and selenium (Se) - because these are necessary for the synthesis and maintenance of sufficient amounts of GSH, MT and NO. Via the Th1/Th2 balance, Zn++, NO, MT and GSH collectively determine the progress and outcome of many diseases. Disregulation of the Th1/Th2 balance is responsible for autoimmune disorders such as diabetes mellitus. Under Th2, levels of interleukin-4 (II-4), II-6, II-10, leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) are raised, while levels of II-2, Zn++, NO and other substances are lowered. This makes things easier for viruses like HIV-1 which multiply in Th2 cells but rarely, if ever, in Th1 cells. AIDS viruses (HIVs) enter immune cells with the aid of the CD4 cell surface receptor in combination with a number of co-receptors which include CCR3, CCR5 and CXCR4. Remarkably, the cell surface receptor for LTB4 (BLTR) also seems to act as a co-receptor for CD4, which helps HIVs to infect immune cells. The Th2 cytokine II-4 increases the number of CXCR4 and BLTR co-receptors, as a result of which, under Th2, the HIV strains that infect immune cells are precisely those that are best able to accelerate the AIDS disease process. The II-4 released under Th2 therefore not only promotes the production of more HIVs and the rate at which they infect immune cells, it also stimulates selection for the more virulent strains. Zn++ inhibit LTB4 production and numbers of LTB4 receptors (BLTRs) in a concentration-dependent way. Zn++ help cells to keep their LTB4 'doors' shut against the more virulent strains of HIV. Moreover, a sufficiency of Zn++ and NO prevents a shift of the Th1/Th2 balance towards Th2 and thereby slows the proliferation of HIV, which it also does by inactivating the HIV protease. Research makes it look likely that deficiencies of ENs such as zinc promote the proliferation of Th2 cells at the expense of Th1 cells. Zinc deficiency also promotes cancer. Under the influence of Th1 cells, zinc inhibits the growth of tumours by activating the endogenous tumour-suppressor endostatin, which inhibits angiogenesis. The modern Western diet, with its excess of refined products such as sugar, alcohol and fats, often contains, per calorie, a deficiency of ENs such as zinc, selenium and vitamins A, B, C and E, which results in disturbed immune functions, a shifted Th1/Th2 balance, chronic (viral) infections, obesity, atherosclerosis, autoimmunity, allergies and cancer. In view of this, an optimization of dietary composition would seem to give the best chance of beating (viral) epidemics and common (chronic) diseases at a realistic price.
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PMID:Modern diets and diseases: NO-zinc balance. Under Th1, zinc and nitrogen monoxide (NO) collectively protect against viruses, AIDS, autoimmunity, diabetes, allergies, asthma, infectious diseases, atherosclerosis and cancer. 1049 17

Leptin is an adipocyte-secreted hormone that centrally regulates weight control. However, leptin receptor is expressed not only in the central nervous system, but also in other systems such as reproductive and hematopoietic tissues. Human leptin has previously been shown to enhance cytokine production by murine peritoneal macrophages and human circulating monocytes. In this paper we have assessed the presence of leptin receptors in peripheral human T lymphocytes and we have studied their functional role. Both CD4(+) and CD8(+) T lymphocytes express leptin receptors. Moreover, we show that human leptin dose-dependently enhances proliferation and activation of human circulating T lymphocytes when they are costimulated by PHA or Con A. Leptin alone was not able to activate T lymphocytes. To confirm a direct effect of leptin on T lymphocytes, monocytes were extracted by adhesion to culture flasks. The early activation surface marker CD69 was then induced in both CD4(+) and CD8(+) T lymphocytes after 8 h stimulation with PHA or Con A. Leptin dose-dependently enhanced stimulated CD69 expression. Moreover, leptin dose-dependently enhanced the expression of the late activation markers CD25 and CD71 in both CD4(+) and CD8(+) T lymphocytes after 48 h stimulation with PHA or Con A. Finally, we have found that leptin modulates CD4(+) T lymphocyte activation toward Th1 phenotype by stimulating the synthesis of IL-2 and IFN-gamma. These results demonstrate the presence of the leptin receptor in human circulating CD4(+) and CD8(+) T lymphocytes and a functional role of leptin as a modulator (enhancer) of lymphocyte stimulation with a shift toward Th1 cytokine-production profile. This function of leptin may have some relevance in the pathophysiology of immunologic alterations related to obesity.
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PMID:Human leptin enhances activation and proliferation of human circulating T lymphocytes. 1067 71

Despite widespread nutrient deficiencies, a substantial proportion of the MIDAS cohort exhibits obesity, which has been linked to immune dysregulation in other clinical settings. Herein, the effects of obesity on immune function, disease progression, and mortality were evaluated longitudinally in 125 HIV-1-seropositive drug users, with comparison measures in 148 HIV-1-seronegative controls. Data were collected at a community clinic from 1992 to 1996, before administration of highly active antiretroviral therapy. Results indicated that overweight/obesity, defined as body mass index (BMI; kg/m2) > or =27, was evident in 18% of the HIV-1-seropositive patients and 29% of the seronegative patients. At baseline, no significant immunologic differences were observed among lean, nonobese, and obese groups. Over an 18-month period, 60.5% of the nonobese HIV-1-seropositive patients exhibited a 25% decline in CD4 cell count, compared with 18% of the obese patients (p<.004). During the follow-up period, 38% of the lean and 13% of the nonobese study subjects died of HIV-1-related causes. Measurements of BMI were inversely associated with progression to death, independent of CD4 count <200 cells/mm3 (p<.02). These data suggest that mild-to-moderate obesity in HIV-1-infected chronic drug users does not impair immune function and is associated with better HIV-1-related survival.
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PMID:When obesity is desirable: a longitudinal study of the Miami HIV-1-infected drug abusers (MIDAS) cohort. 1070 60

HIV infection induces an early decrease of cholesterol and a late increase of triglycerides (TG) with a reduction of HDL. These changes are proportional with the lowering of CD4, which reflects the infection's severity. Both the increase of TG synthesis and the decrease of TG catabolism, in relation with a reduction of lipoprotein lipase activity, are responsible of these changes. Moreover, LDL catabolism is enhanced by macrophage scavenger receptors, due to a high proportion of small, dense LDL which are more easily oxidized. Many cytokines (interferon alpha, interleukins, TNF) play probably a pathogenic role in the dyslipidemia. Some HIV patients who received antiproteases may develop lipodystrophy with central obesity, insulino-resistance, glucose intolerance and sometimes diabetes (like in syndrome X). Other patients present a cushingoid, buffalo hump. This complication may be observed also with antiretroviral treatment other than antiproteases. The physiopathology of these findings could be in relation with structural homologies between antiproteases and some important proteins, involved in lipid and adipocyte metabolism. Cardiovascular risk linked to these perturbations is evident. The treatment is not different from the treatment for seronegative, hyperlipidemic patients: struggle against risk factors, diet advices, fibrates or statins. The antiproteases bring huge contribution to the prognosis of AIDS patients but the risk of cardiovascular complications could impair this therapeutic progress. So, it is essential to understand the pathogeny of these complications in order to discover new antiproteases, without these adverse side effects.
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PMID:[Lipids and AIDS]. 1074 83

Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a nuclear receptor transcription factor that regulates cell growth, differentiation, and homeostasis. PPARgamma agonists are potent therapeutic agents for type 2 diabetes, obesity, and inflammation. Experimental allergic encephalomyelitis (EAE) is a Th1 cell-mediated inflammatory demyelinating autoimmune disease model of multiple sclerosis. We have shown recently that PPARgamma agonists inhibit EAE by blocking IL-12 production, IL-12 signaling, and neural Ag-induced Th1 differentiation. In this study, we show that the PPARgamma-deficient heterozygous mice develop an exacerbated EAE with prolonged clinical symptoms than the wild-type littermates, following immunization with myelin oligodendrocyte glycoprotein (MOG) p35-55 peptide. The exacerbation of EAE in PPARgamma(+/-) mice associates with an increased expansion of CD4(+) and CD8(+) T cells and expression of CD40 and MHC class II molecules in response to MOGp35-55 Ag. The PPARgamma(+/-) mice also showed an increase in T cell proliferation and Th1 response to MOGp35-55 Ag than the wild-type littermates. These findings suggest that PPARgamma be a critical physiological regulator of CNS inflammation and demyelination in EAE and perhaps multiple sclerosis and other Th1 cell-mediated autoimmune diseases.
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PMID:Peroxisome proliferator-activated receptor-gamma-deficient heterozygous mice develop an exacerbated neural antigen-induced Th1 response and experimental allergic encephalomyelitis. 1463 82

Recently, we identified in normally type 1 diabetes-prone NOD/LtJ mice a spontaneous new leptin receptor (LEPR) mutation (designated Lepr(db-5J)) producing juvenile obesity, hyperglycemia, hyperinsulinemia, and hyperleptinemia. This early type 2 diabetes syndrome suppressed intra-islet insulitis and permitted spontaneous diabetes remission. No significant differences in plasma corticosterone, splenic CD4(+) or CD8(+) T-cell percentages, or functions of CD3(+) T-cells in vitro distinguished NOD wild-type from mutant mice. Yet splenocytes from hyperglycemic mutant donors failed to transfer type 1 diabetes into NOD.Rag1(-/-) recipients over a 13-week period, whereas wild-type donor cells did so. This correlated with significantly reduced (P < 0.01) frequencies of insulin and islet-specific glucose-6-phosphatase catalytic subunit-related protein-reactive CD8(+) T-effector clonotypes in mutant mice. Intra-islet insulitis was also significantly suppressed in lethally irradiated NOD-Lepr(db-5J)/Lt recipients reconstituted with wild-type bone marrow (P < 0.001). In contrast, type 1 diabetes eventually developed when mutant marrow was transplanted into irradiated wild-type recipients. Mitogen-induced T-cell blastogenesis was significantly suppressed when splenic T-cells from both NOD/Lt and NOD-Lepr(db-5J)/Lt donors were incubated with irradiated mutant peritoneal exudate cells (P < 0.005). In conclusion, metabolic disturbances elicited by a type 2 diabetes syndrome (insulin and/or leptin resistance, but not hypercorticism) appear to suppress type 1 diabetes development in NOD-Lepr(db-5J)/Lt by inhibiting activation of T-effector cells.
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PMID:Novel leptin receptor mutation in NOD/LtJ mice suppresses type 1 diabetes progression: II. Immunologic analysis. 1638 Apr 90

Leptin has direct effects not only on neuroendocrine function and metabolism, but also on T cell-mediated immunity. We report in this study that leptin receptor (ObR) is expressed on resting normal mouse CD4(+), CD8(+), B cells, and monocyte/macrophages. ObR expression is up-regulated following cell activation, but with different kinetics, in different lymphocyte subsets. Leptin binding to ObR results in increased STAT-3 activation in T cells, with a different activation pattern in resting vs anti-CD3 Ab stimulated T cells. Leptin also promotes lymphocyte survival in vitro by suppressing Fas-mediated apoptosis. B lymphocytes appear to be more susceptible to the antiapoptotic effects of leptin, and they show higher surface expression of ObR, compared with T cells. Moreover, CD4(+) T cells isolated from ObR-deficient mice displayed a reduced proliferative response, compared with normal controls. Furthermore, ObR/STAT-3-mediated signaling in T lymphocytes is decreased in the diet-induced obese mouse model of obesity and leptin resistance. In summary, our findings show that the ObR is expressed on normal mouse lymphocyte subsets, that leptin plays a role in lymphocyte survival, and that leptin alters the ObR/STAT-3-mediated signaling in T cells. Taken together, our data further support the notion that nutritional status acting via leptin-dependent mechanisms may alter the nature and vigor of the immune response.
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PMID:Leptin receptor expression and signaling in lymphocytes: kinetics during lymphocyte activation, role in lymphocyte survival, and response to high fat diet in mice. 1675 22

HIV has classically been a wasting disease. However, in the United States, obesity is increasingly common among HIV-infected individuals receiving effective antiviral treatment. The risks of obesity are unclear in HIV, although the increased prevalence of diabetes and cardiovascular disease in the presence or absence of obesity causes growing concern. This study aimed to assess the effects of weight loss (through energy restriction combined with aerobic and resistance exercise) on body composition, body fat distribution, resting energy expenditure, quality of life (QOL), strength and fitness, and metabolic risk factors in obese, HIV-infected women. Eighteen HIV-infected women with a body mass index of 30 or more completed a 12-week weight loss program. Before and after the intervention, body composition and fat distribution by dual energy x-ray absorptiometry and whole-body magnetic resonance imaging, resting energy expenditure by indirect calorimetry, QOL, strength, and fitness were measured. Insulin sensitivity by intravenous glucose tolerance test and circulating cardiovascular risk factors (including lipids, tissue plasminogen activator, and plasminogen activator inhibitor 1) were measured in a subset (n = 9). Daily food intake and total body weight decreased (mean +/- SD) by 3195 +/- 477 kJ and 6.7 +/- 4.2 kg, respectively. Weight lost was 95.5% fat by dual energy x-ray absorptiometry or 6.2 L of subcutaneous adipose tissue, 0.7 L visceral adipose tissue, and 0.8 L skeletal muscle by magnetic resonance imaging. Resting energy expenditure fell approximately 419 kJ, strength and fitness increased by 28.9% +/- 18.5% and 36.8% +/- 41.6%, respectively, and QOL improved in 11 of 13 dimensions. There was significant insulin resistance in the subset with metabolic measurements at baseline, and at follow-up there was no improvement in fasting glucose, insulin, or insulin sensitivity, nor was there any change in fasting lipids, tissue plasminogen activator, or plasminogen activator inhibitor 1. There was no significant change in CD4 count or HIV viral load. In conclusion, moderate weight loss achieved by a short-term program of diet and exercise in obese HIV-positive women appears safe and induces loss of adiposity in both the subcutaneous adipose tissue and visceral adipose tissue regions. Despite reduced food intake, weight and fat loss, as well as improvements in strength, fitness, and QOL, the lack of improvement in metabolic parameters suggests that additional interventions may be necessary to reduce the risk of diabetes and cardiovascular disease in this population.
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PMID:Body composition and metabolic effects of a diet and exercise weight loss regimen on obese, HIV-infected women. 1697 3

The immune response to foreign or self antigens mediates liver damage during viral or autoimmune hepatitis. However, it now appears that also specific antigen-independent liver diseases, where liver damage has been attributed to occur from oxygen radical formation, seem to be mediated by cells of the innate and adaptive immune response. These liver disorders include alcoholic liver disease, non-alcoholic fatty liver disease or non-alcoholic steatohepatitis, and ischemia/reperfusion injury that impairs the function of liver grafts. Here it seems that breakdown of the gastrointestinal barrier might increase the concentration of bacterial toxins in the portal blood, which then activate cells of the innate immune system, e. g., Kupffer cells, but, depending on the nature of the toxin, probably also conventional T cells. Invariant NKT cells which specifically recognize glycolipid antigens were supposed to become activated during metabolic disorders related to obesity. However, both steatohepatitis as well as ischemia/reperfusion injury are associated with a Th1 cytokine response characterized by IFNgamma and TNFalpha elevation, that might reflect an NKT cell response on the one hand, but also conventional T lymphocytes, in particular CD4 (+) T cells, are critical for the pathophysiology of these disorders. In 1992 we described a model of T cell-dependent liver injury inducible by the T cell-mitogenic lectin concanavalin A. This model of immune-mediated liver injury was intensively used to study pathophysiological immune effector mechanisms as well as cytokine signaling important for hepatocellular apoptosis, inhibition of apoptosis and regeneration. Recently it became evident that the inflammatory response in this model is regulated by specific cytokine signals as well as by immune regulator cells. The immune-regulatory functions of the liver are of particular interest with respect to the scavenger function of this organ, being continuously exposed to foreign antigenic material from the gut which should be eliminated without causing chronic disease.
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PMID:Cellular and cytokine-mediated mechanisms of inflammation and its modulation in immune-mediated liver injury. 1723 22


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