adiponectin (long) Obesity is not just calories in/calories out

[Guest guest]

Obesity is not just about calories in/calories out:

1. The AMP-activated protein kinase (AMPK) is an evolutionarily conserved sensor of cellular energy status, and recent data demonstrate that it also plays a critical role in systemic energy balance. AMPK integrates nutritional and hormonal signals in peripheral tissues and the hypothalamus. It mediates effects of adipokines (leptin, adiponectin, and possibly resistin) in regulating food intake, body weight, and glucose and lipid homeostasis. AMPK is regulated by upstream kinases of which the tumor suppressor, LKB1, is the first to be identified. Complex signaling networks suggest that AMPK may prevent insulin resistance, in part by inhibiting pathways that antagonize insulin signaling. Through signaling, metabolic, and gene expression effects, AMPK enhances insulin sensitivity and fosters a metabolic milieu that may reduce the risk for obesity and type 2 diabetes. PMID: 16054041

2. Adiponectin is an adipocytokine with lowered blood levels in obesity and Type 2 diabetes mellitus. ...

CONCLUSIONS: The carriers of the His111 allele may have a higher risk of developing Type 2 diabetes mellitus. Racial differences were found between Blacks and Whites in body composition and lipids according to ACDC genotypes. Sequence variants in the adiponectin gene appear to be associated with diabetes and diabetes-related phenotypes. PMID: 16028335.

3. Adipokines: therapeutic targets for metabolic syndrome.

Recently, many investigators have reported that adipocytes secrete a variety of bioactive molecules, termed adipokines (adipocytokines), including TNFalpha, IL-6, leptin, adiponectin, resistin and so on. These adipokines play pivotal roles in energy homeostasis by affecting insulin sensitivity, glucose and lipid metabolisms, food intake, the coagulation system and inflammation. PMID: 16026271

4. Low adiponectin level in young normotensive men with a family history of essential hypertension.

Adiponectin concentration was the only independent determinant of ISI in a multiple regression analysis. Our results showed that adiponectin level was significantly decreased and that this was accompanied by reduced insulin sensitivity in young, nonobese and normotensive men with a family history of essential hypertension. Phenotype of reduced adiponectin level as an earlier penetrance may be especially useful in genetic analyses of insulin resistance and essential hypertension. PMID: 16025741

{A reason to measure RMR}

5. Resting metabolic rate is an important predictor of serum adiponectin concentrations: potential implications for obesity-related disorders.

CONCLUSIONS: Low resting metabolism (RMR) is associated with high serum adiponectin. We speculate that subjects with low RMR, who are theoretically at greater risk of obesity-related disorders, are especially protected by adiponectin. Clinical Trial PMID: 16002795

6. Influence of gender, age and renal function on plasma adiponectin level: the Tanno and Sobetsu study.

CONCLUSIONS: A decrease in adiponectin clearance in the kidney may be the cause of high levels of adiponectin in the elderly. Adiponectin level seems to be influenced more strongly by BUN than by sex hormones and to be increased by a decline in renal function with aging. PMID: 15994750

{Is there a drug for it?}

7. Pravastatin does not affect insulin sensitivity and adipocytokines levels in healthy nondiabetic patients.

CONCLUSION: A 12-week treatment with pravastatin 40 mg/d does not change the QUICKI index(Quantitative Insulin Sensitivity Check Index) and leptin and adiponectin levels in healthy volunteers. In addition, our results emphasize the importance of sex and BMI in the determination of both adiponectin and leptin. Adiponectin was also related to QUICKI index, whereas this relation was not found with leptin. Clinical Trial Randomized Controlled Trial PMID: 15988706

{This says exercise alone won't help, takes diet and exercise.}

8. Effects of diet and/or exercise on the adipocytokine and inflammatory cytokine levels of postmenopausal women with type 2 diabetes.

Giannopoulou I, Fernhall B, Carhart R, Weinstock RS, Baynard T, Figueroa A, Kanaley JA.

Department of Exercise Science, Syracuse University, NY 13244, USA.

This study examined the independent and combined effects of diet and exercise on adipocytokine and inflammatory cytokines in postmenopausal women with type 2 diabetes. Using a randomized, controlled design, 33 women (age, 50-70 years) were assigned to diet alone (D), exercise alone (EX), or diet + exercise (D + E) for 14 weeks. Before and after the interventions, blood samples for adipocytokines and inflammatory markers were drawn, a meal test was performed, and abdominal fat distribution was measured by magnetic resonance imaging (MRI). Body weight decreased approximately 4.5 +/- 0.6 kg ( P < .05) after the D and D + E interventions, whereas only small changes in body weight were found with the exercise-alone intervention. Plasma C-reactive protein levels were decreased by approximately 15% with all 3 interventions, whereas leptin levels were reduced with the D and D + E intervention (D: pre = 48.7 +/- 6.0, post = 38.9 +/- 5.0 ng/mL; D + E: pre = 38.5 +/- 6.0, post = 22.9 +/- 5.0 ng/mL; P < .05) with no differences between groups. There was a trend for leptin levels to decrease in the EX group ( P = .06). Plasma resistin levels were not altered by the 3 interventions from pre- to posttreatment (D: pre = 6.9 +/- 0.6, post = 6.2 +/- 0.4 ng/mL; D + E: pre = 5.6 +/- 0.6, post = 5.7 +/- 0.4 ng/mL; E: pre = 6.2 +/- 0.6, post = 5.9 +/- 0.6 ng/mL, P > .05), and no differences in adiponectin and tumor necrosis factor alpha (TNF- alpha ) levels were found. Visceral adipose tissue and tumor necrosis factor alpha were the only predictors of calculated insulin resistance ( P < .05), explaining 43% of the variability. A typically prescribed weight loss program with lifestyle changes resulted in few changes in adipocytokines and inflammatory cytokines in older women with type 2 diabetes, suggesting that dramatic weight loss or clinical interventions are needed. Clinical Trial Randomized Controlled Trial PMID: 15988694

{Other relationships, bones}

9. Adiponectin is associated with bone mineral density in perimenopausal women.

Significant relationships were observed between plasma adiponectin and bone mineral content, total bone mineral density (BMD) and lumbar spine BMD values (r > - 0.36; p < 0.05). Furthermore, adiponectin had a significant negative association with total BMD (beta = - 1.228; p = 0.004) and lumbar spine BMD (beta = - 0.312; p = 0.005) independent of the influence that other measured body compositional, hormonal or physical performance factors may exert on BMD. Adiponectin was also significantly related to waist-to-hip ratio (WHR) (beta = - 2.300; p = 0.002) and fasting insulin resistance index (FIRI) (beta = - 0.006; p = 0.007) in separate regression models. No relationship was observed between leptin and measured bone, physical performance and insulin resistance values. Leptin significantly correlated to BMI (beta = 0.018; p = 0.034), lean body mass (beta = 0.025; p = 0.024) and fat mass (beta = 0.019; p = 0.001) in separate regression models. In conclusion, the results of present study show that circulating adiponectin appears to exert an independent effect on BMD in perimenopausal women and may represent a link between adipose tissue and bone mineral density. PMID: 15971153

{Also atherosclerosis:}

10. ...adiponectin, also a newfound adipose tissue-specific collagen-like protein, has been noted recently as an important antiatherogenic as well as antidiabetic protein. The function of adipocytokine secretion might be regulated dynamically by nutritional state. Visceral fat accumulation causes dysfunction of adipocytes including oversecretion of tumor necrotizing factor alpha, plasminogen activator inhibitor 1, and heparin-binding epidermal growth factor-like growth factor, as well as hyposecretion of adiponectin, which results in the development of a variety of metabolic and circulatory diseases. In this review, the importance of adipocytokines, including adiponectin, is discussed with respect to atherosclerosis. PMID: 15968578

11. CONCLUSION: In summary, our study describes an influence of SAT topography on adiponectin serum levels and provides first evidence that incipient atherosclerosis is associated with low serum levels of this adipocytokine. PMID: 15928248

{more}

The question arising from these observations is how the secretory pattern of adipose tissue can be modified by dietary and pharmacological measures to reduce the health risks of obesity. PMID: 15960861

Thiazolidinediones decrease plasma levels of C reactive protein, possess antiinflammatory effects through a reduction of inflammatory cytokines production, decrease free fatty acids levels, antagonize angiotensin II effects, increase adiponectin expression and production, etc. Pathophysiological mechanisms leading to vascular function impairment and their evaluation techniques are described, as well as the main thiazolidinediones beneficial effects on these mechanisms, which may lead to vascular prevention and/or protection in high cardiovascular risk insulin resistant and/or type 2 diabetic patients. PMID: 15959408

We demonstrated that hypoadiponectinemia and insulin resistance are associated with nonalcoholic fatty liver disease (NAFLD) independent of obesity. PMID: 15953863

The largest depots are found subcutaneously and in the abdominal region. Several secretory proteins are synthesised in adipose tissue including leptin, resistin, adiponectin, tumor necrosis factor (TNFalpha), angiotensinogen, adipsin, acylation-stimulating protein, retinol-binding protein (RBP), interleukin (IL)-1b, IL-6, IL-8, IL-10, plasminogen activator inhibitor-1 (PAI-1), fasting-induced adipose factor, fibrinogen-angiopoietin-related protein, metallothionein, tissue factor (TF), complement C3, fibronectin, haptoglobin, entactin/nidogen, collagen VI alpha 3, pigment epithelium-derived factor (PEDF), hippocampal cholinergic neurostimulating peptide (HCNP), neutrophil gelatinase-associated lipocalin (NGAL) and adiponutrin. Fatty acids may influence the expression of adipokines like leptin, resistin or adiponectin directly by interaction with transcription factors, or indirectly via unknown mechanisms possibly linked to fatty acid oxidation, synthesis or storage. Because fatty acids are the main components of adipose tissue, it is of essential interest to clarify the biological effects of different types of fatty acids on the expression of relevant adipokines. PMID: 15949695

{cancer?}

Adiponectin, a major adipose cytokine, plays a crucial role in the inhibition of metabolic syndrome by acting on such cell types as muscle cells and hepatocytes. Furthermore, evidence suggests that adiponectin may influence cancer pathogenesis. Adiponectin occurs in non-proteolytic (full-length adiponectin: f-adiponectin) and proteolytic (globular adiponectin: g-adiponectin) forms in various oligomeric states. Different forms of adiponectin show distinct biological effects through differential activation of downstream signaling pathways. Here we identify c-Jun NH(2)-terminal kinase (JNK), and signal transducer and activator of transcription 3 (STAT3) as common downstream effectors of f- and g-adiponectin. f- and g-adiponectin both stimulate JNK activation in prostate cancer DU145, PC-3, and LNCaP-FGC cells, hepatocellular carcinoma HepG2 cells, and C2C12 myoblasts. Furthermore, both f- and g-adiponectin drastically suppress constitutive STAT3 activation in DU145 and HepG2 cells. These suggest that JNK and STAT3 may constitute a universal signaling pathway to mediate adiponectin's pathophysiological effects on metabolic syndrome and cancer. PMID: 15936715

Our results suggest that IL6 (-174) G/C polymorphism is associated with insulin resistance and increased adipose tissue IL6 gene expression, which can impair adiponectin production. PMID: 15919832