Review Article: Adiponectin: Its role in kidney disease

The multifactorial glycoprotein, adiponectin has demonstrable insulin-sensitizing, anti-atherogenic and anti-inflammatory properties. However, despite the prevalence of both insulin-resistance and vascular disease in patients with end-stage kidney disease, levels of adiponectin are high. Adiponectin circulates in different sizes (the high-molecular-weight (HMW) isoform is thought to be the most insulin-sensitizing type) and binds to two receptors, adiponectin receptors (AdipoR) 1 and 2. The adiponectin/receptor system appears to be upregulated in end-stage kidney disease possibly as an appropriate counter-regulatory response to the uraemic milieu. In contrast, adiponectin and its HMW isoform, AdipoR mRNA expression on peripheral blood mononuclear cells decrease after kidney transplantation, likely secondary to immunosuppression and/or an improvement in glomerular filtration rate and the uraemic environment. Adiponectin has also been detected in the urine of patients with proteinuric kidney disease. The presence of AdipoR on an immortal cell line of proximal tubular epithelial cells (HK-2) and an increased amount of intact HMW isoform in the urine of patients with various forms of proteinuria lead us to speculate about the potential role of urinary adiponectin. This review will also discuss the structure and function of adiponectin and its potential relevance to patients with kidney disease and the different factors that may influence the metabolism of this protein in kidney failure.     

Pattern of Expression of Adiponectin Receptors in Human Liver and its Relation to Nonalcoholic Steatohepatitis

BACKGROUND: Adiponectin has antisteatosis-anti-inflammatory properties and its circulating levels are reduced in nonalcoholic steatohepatitis (NASH). METHODS: To assess the role of adiponectin in NASH, we measured expression of adiponectin gene (APM1) and receptors (AdipoR1/AdipoR2) in liver and subcutaneous and visceral fat in subjects with biopsy-proven NASH or pure steatosis (PS). In 103 subjects undergoing gastric bypass or elective abdominal surgery (17 with normal liver histology (C), 52 with PS, and 34 with NASH), RNA was extracted from tissue samples, and quantification of APM1, AdipoR1, and AdipoR2 was carried out by real-time polymerase chain reaction. RESULTS: In NASH vs C, circulating adiponectin levels (3.6[2.4] vs 5.3[4.3] mug/ml, median[interquartile range], p < 0.05) and adiponectin concentrations, APM1, AdipoR1, and AdipoR2 expression in visceral fat were all reduced (p 相似文献   

Total and high molecular weight adiponectin concentrations in plasma of patients with end-stage renal disease before and after peritoneal dialysis

Background: Adiponectin is an antiatherogenic adipocyte‐derived proteins. The level of plasma adiponectin is inversely correlated to cardiovascular risk in patients with end‐stage renal disease (ESRD). The aim of this study was to elucidate the changes of adiponectin concentrations in newly diagnosed ESRD patients after peritoneal dialysis. Methods: In 16 newly diagnosed ESRD patients, total concentrations of adiponectin and high molecular weight (HMW) adiponectin, the HMW ratio (HMWR; ratio of the plasma level of HMW adiponectin to that of total adiponectin), the body mass index (BMI), insulin concentrations, blood glucose and estimation of the insulin sensitivity index by the homeostasis model assessment (HOMR_IR) were compared before and after 1 year of peritoneal dialysis. Results: Plasma total adiponectin was decreased from 15.52 ± 9.35 μg/mL to 11.80 ± 6.84 μg/mL (P = 0.046), HMW adiponectin was decreased from 9.05 ± 6.48 μg/mL to 4.83 ± 4.15 μg/mL (P = 0.009), and HMWR was decreased from 0.51 ± 0.18 to 0.35 ± 0.20 (P = 0.008). Total and HMW adiponectin/BMI ratio was decreased. The BMI was increased from 25.2 ± 5.7 to 25.8 ± 6.2 (P = 0.036). The HOMR_IR, insulin level and lipid profile were not changed. Conclusion: Total adiponectin, HMW adiponectin and HMWR were decreased in newly diagnosed ESRD patients after 1 year of peritoneal dialysis. The factors that influence the decrease of the level of adiponectin should be studied in a larger prospective study.     

Normal total and high molecular weight adiponectin levels in adults with cystic fibrosis

Cystic fibrosis related diabetes (CFRD) is an important complication of CF that increases mortality. Adiponectin, an adipokine secreted from adipose tissue, plays an important role in fatty acid and glucose metabolism. Lower total adiponectin (TA) levels have been linked to the risk of developing type 2 diabetes. However, studies show that the high molecular weight isoform (HMW), thought to be more active than TA, might be a better indicator of insulin sensitivity.Our aim was to determine the association between HMW and insulin sensitivity in CF subjects and determine if other factors might modulate its levels.Thirteen control subjects and 47 CF adults (16 with normal glucose tolerance, 16 prediabetic and 15 with CFRD) underwent an oral glucose tolerance test. Blood samples were taken at time 0, 30, 60, 90 and 120 min. Body mass index, fibrinogen, glucose and insulin, TA and HMW were measured in every subject. Regression analysis was used to determine the association between TA, HMW and glucose (fasting glucose, 2 h glucose and glucose AUC) as well as insulin (fasting insulin, insulin AUC, and Stumvoll insulin sensitivity index) parameters.TA and HMW levels were similar between CF patients and controls and were not associated to insulin sensitivity. TA was negatively associated to insulin AUC (p = 0.0108) and 2 h glucose (p = 0.0116) in controls while these relationships were either weakly negative (p = 0.0208) or weakly positive (p = 0.0105) in CF patients. Also, HMW was negatively associated to insulin (p = 0.00301) and glucose AUC (p = 0.0546) in controls whereas these associations were positive in CF patients (p = 0.0388, p = 0.0232 respectively).In conclusion, our exploratory study on HMW adiponectin demonstrated similar levels of TA and HMW between CF patients and controls and different relationships between forms of adiponectin to glucose metabolism and insulin in CF.     

Steroid pulse therapy impaired endothelial function while increasing plasma high molecule adiponectin concentration in patients with IgA nephropathy.

BACKGROUND: Decreased plasma adiponectin is associated with impaired endothelial function and, thereby, increased risk for cardiovascular events. Glucocorticoid (GC) affects vascular endothelial cells either favourably or harmfully depending upon the dosages and duration. We examined the effect of GC pulse therapy on vascular endothelial function. METHODS: Fourteen young patients with IgA nephropathy were evaluated for flow-mediated vasodilation (FMD), plasma levels of adiponectin both in high molecular weight (HMW adiponectin) form and in single molecular form (total adiponectin), hepatocyte growth factor (HGF), asymmetric dimethylarginine (ADMA), and high-sensitive C-reactive protein, before and after a course of GC pulse therapy. RESULTS: GC pulse therapy significantly decreased FMD (from 7.2 +/- 2.6 to 5.7 +/- 2.5%, P < 0.01). Meanwhile, plasma adiponectin levels were significantly augmented (total adiponectin: from 10.2 +/- 4.0 to 12.1 +/- 6.3 microg/ml, P < 0.05; HMW: from 6.5 +/- 3.2 to 7.7 +/- 3.3 microg/ml, P < 0.05). In parallel, elevated concentrations of serum HGF (from 0.28 +/- 0.12 to 0.63 +/- 0.38 ng/ml, P < 0.01) and plasma ADMA (from 0.45 +/- 0.07 to 0.53 +/- 0.04 nmol/ml, P < 0.05) were observed. CONCLUSIONS: GC pulse therapy impaired endothelial function while increasing plasma adiponectin levels, which may in turn restore the endothelial function in patients with IgA nephropathy.     

Association of age with muscle mass, fat mass and fat distribution in non-diabetic haemodialysis patients.

BACKGROUND: In the general population, aging induces changes in body composition, such as sarcopenia or a relative increase in visceral fat, but it remains unclear if similar changes occur in elderly haemodialysis (HD) patients. METHODS: Age-related changes in muscle and fat mass and fat distribution in the thigh and abdomen were cross-sectionally investigated in Japanese HD patients. The thigh muscle area (TMA), thigh intermuscular fat area (IMFA), thigh subcutaneous fat area (TSFA), abdominal muscle area (AMA), abdominal visceral fat area (AVFA) and abdominal subcutaneous fat area (ASFA) were measured by computed tomography in 134 non-diabetic patients between 21 and 82 years on HD. AMA, AVFA and ASFA were also measured in 70 age-matched controls. RESULTS: Muscle mass, fat mass and fat distribution differed significantly with age in both HD patients and controls, without significant differences in BMI. In both male and female HD patients, TMA and AMA showed significant negative correlations with age. All measures of subcutaneous fat-including TSFA, ASFA and the triceps skinfold thickness, were inversely associated with age in the female patients. In contrast, both IMFA and AVFA showed significant positive correlations with age in both male and female patients. The increase in the AVFA/ASFA ratio with age suggests progression of visceral fat accumulation in the elderly HD patients. Controls showed similar relationships between age and muscle mass and visceral fat accumulation. CONCLUSIONS: We found an association between age and decrease in muscle mass as well as increase in visceral and intermuscular fat in non-diabetic HD patients. Such changes may be associated with the metabolic abnormalities and increased mortality in elderly HD patients.     

Adiponectin in renal disease: relationship to phenotype and genetic variation in the gene encoding adiponectin

BACKGROUND: The prevalence of cardiovascular disease (CVD) and inflammation is high in patients with end-stage renal disease (ESRD). Adiponectin is an adipocytokine that may have significant anti-inflammatory and anti-atherosclerotic effects. Low adiponectin levels have previously been found in patients with high risk for CVD. METHODS: In a cohort of 204 (62% males) ESRD patients aged 52 +/- 1 years the following parameters were studied: presence of CVD, body composition, plasma adiponectin (N= 107), cholesterol, triglycerides, HDL-cholesterol, serum leptin, high-sensitivity C-reactive protein (hs-CRP), urinary albumin excretion (UAE), and single-nucleotide polymorphisms (SNPs) in the apM1 gene at positions -11391, -11377, 45, and 276. Thirty-six age- (52 +/- 2 years) and gender-matched (64% males) healthy subjects served as control subjects. RESULTS: Markedly (P < 0.0001) elevated median plasma adiponectin levels were observed in ESRD patients (22.2 microg/mL), especially type 1 diabetic patients (36.8 microg/mL), compared to control subjects (12.2 microg/mL). Log plasma adiponectin correlated to visceral fat mass (R=-0.29; P < 0.01) and Log hs-CRP (R=-0.26; P < 0.01). In a stepwise (forward followed by backward) multiple regression model only type-1 diabetes (P < 0.001) and visceral fat mass (P < 0.05) were independently associated with plasma adiponectin levels. The adiponectin gene -11377 C/C genotype was associated with a lower prevalence of CVD (25 vs. 42%) compared to the G/C genotype. CONCLUSION: The present cross-sectional study demonstrates that, whereas genetic variations seem to have a minor impact on circulating adiponectin levels, lower visceral fat mass and type 1 diabetes mellitus are associated with elevated plasma adiponectin levels in ESRD patients. Furthermore, low levels of adiponectin are associated with inflammation in ESRD.     

Adiponectin as a novel determinant of bone mineral density and visceral fat

Growing evidence suggests that positive associations between fat mass (FM) and bone mineral density (BMD) are mediated by not only biomechanical but also biochemical factors. Adiponectin is a novel adipocyte-derived hormone that regulates energy homeostasis and has anti-inflammatory and anti-atherogenic effects. Unlike other adipokines such as leptin, adiponectin levels decrease in obesity and type 2 diabetes. The purpose of our study was to investigate associations of serum adiponectin with BMD (DXA and QCT), FM (DXA and QCT), and serum leptin and soluble leptin receptor levels in 38 women and 42 men (age 39-81, BMI 17-55, 86% with type 2 diabetes). After adjusting for age, gender, race, smoking, and diabetes status, serum adiponectin was inversely associated with areal BMD (r = -0.20 to -0.3, all P < 0.01), volumetric BMD (r = -0.35 to -0.44, all P < 0.01), and visceral fat volume (r = -0.30, P < 0.01). These associations remained significant after adjusting for whole body fat mass. The associations of adiponectin with subcutaneous fat volume, whole body FM, and serum leptin level were not significant (all P > 0.1). These data suggest that adiponectin may play a role in the protective effects of visceral fat on BMD.     

Effect of antihypertensive agents on plasma adiponectin levels in hypertensive patients with metabolic syndrome

AIM: Plasma adiponectin levels are well associated with metabolic syndrome. However, the relationship between hypertension and plasma adiponectin levels is not clear. Also, there is not enough data about the effects of different antihypertensive regimens on plasma adiponectin levels. METHODS: Ninety-six hypertensive patients (48 male, 48 female) who fulfil the diagnostic criteria of metabolic syndrome were enrolled. Patients were treated for 3 months with metoprolol (n = 18, 100 mg/day), amlodipine (n = 20, 10 mg/day), doxazosin (n = 18, 4 mg/day), ramipril (n = 20, 5 mg/day) and valsartan (n = 20, 80 mg/day). Blood biochemistry and plasma adiponectin concentrations were measured both before and after the study. Insulin resistance was measured by homeostasis assessment index (HOMA). RESULTS: Plasma adiponectin levels were correlated with the total cholesterol (r = -0.244, P = 0.017), triglyceride (r = -0.306, P = 0.002), high-density lipoprotein-cholesterol (r = 0.286, P = 0.005), body mass index (r = -374, P < 0.001), systolic (r = -502, P < 0.001) and diastolic blood pressures (r = -235, P = 0.021). The independent predictors of plasma adiponectin levels were HOMA (beta = -0.199, P = 0.02), body mass index (beta = -0.313, P < 0.001) and systolic blood pressures (beta = -0.483, P < 0.001). Ramipril and valsartan increased the plasma adiponectin levels significantly higher than the other regimens (P < 0.05 for both) while metoprolol did not make a significant effect. CONCLUSION: According to the results, plasma adiponectin levels are associated with the arterial blood pressures, body fat content and the lipid parameters in hypertensive patients with metabolic syndrome. The effects of antihypertensive drugs on plasma adiponectin levels are parallel to their effects on blood pressures and insulin sensitivities. The different effects of several regimens on plasma adiponectin levels and insulin sensitivities may account for the diversity of the cardiovascular outcomes in patients with hypertension.