Adiponectin in peritoneal dialysis patients: a comparison with hemodialysis patients and subjects with normal renal function

Adiponectin-to-leptin ratio and incident chronic kidney disease: Sex and body composition-dependent association

BACKGROUND

The association between the adiponectin-to-leptin ratio (A/L ratio) and the risk of incident chronic kidney disease (CKD) is poorly understood. This study aimed to investigate the association between A/L ratio and the risk of incident CKD and to examine whether such a relationship varied according to sex and body composition.

METHODS

In this prospective community-based cohort, participants with normal kidney function were analysed (N = 5192). The association between the A/L ratio at baseline and the risk of incident CKD, defined as two or more occasions with an estimated glomerular filtration rate of <60 mL/min/m2 or proteinuria of ≥1+ on a dipstick test during the follow-up period, was evaluated using multivariable Cox proportional hazards analyses. Subgroup analyses were conducted based on sex, body mass index (BMI) and the presence of sarcopenia.

RESULTS

The participants' mean age was 57.2 ± 8.3 years, and 53.2% were women. The A/L ratio was higher in men compared with women (1.5 [0.8-3.2] and 0.5 [0.3-0.9] μg/ng, P < 0.001). During a median follow-up of 9.8 [9.5-10.0] years, 417 incident CKD events occurred (8.7 per 1000 person-years). Men in the highest quartile of A/L ratio had a lower risk of incident CKD (adjusted hazard ratio [aHR], 0.57; 95% confidence interval [CI], 0.33-0.99) than those in the lowest quartile. Additionally, a 1.0 increase in A/L ratio was associated with a 12% decreased risk of incident CKD in men (aHR, 0.88; 95% CI, 0.80-0.97). However, no significant association was observed in women. In subgroup analysis stratified by BMI and the presence of sarcopenia, the association between a high A/L ratio and a reduced risk of incident CKD was consistent in men with a BMI < 23.0 kg/m2 and those with sarcopenia. However, no significant association was observed between men with a BMI ≥ 23.0 kg/m2 and those without sarcopenia.

CONCLUSIONS

A high A/L ratio is an independent marker of a reduced risk of incident CKD in men, especially in those with a BMI < 23.0 kg/m2 and sarcopenia.

Adipokines and Myokines as Markers of Malnutrition and Sarcopenia in Patients Receiving Kidney Replacement Therapy: An Observational, Cross-Sectional Study

Chronic kidney disease (CKD) is linked to an elevated risk of malnutrition and sarcopenia, contributing to the intricate network of CKD-related metabolic disorders. Adipokines and myokines are markers and effectors of sarcopenia and nutritional status. The aim of this study was to assess whether the adipokine-myokine signature in patients on kidney replacement therapy could help identify malnutrition and sarcopenia. The study involved three groups: 84 hemodialysis (HD) patients, 44 peritoneal dialysis (PD) patients, and 52 kidney transplant recipients (KTR). Mean age was 56.1 ± 16.3 years. Malnutrition was defined using the 7-Point Subjective Global Assessment (SGA) and the Malnutrition-Inflammation Score (MIS). Sarcopenia was diagnosed based on reduced handgrip strength (HGS) and diminished muscle mass. Concentrations of adipokines and myokines were determined using the enzyme-linked immunosorbent assay (ELISA). 32.8% of all study participants were identified as malnourished and 20.6% had sarcopenia. For malnutrition, assessed using the 7-Point SGA, in ROC analysis albumin (area under the curve (AUC) 0.67 was the best single biomarker identified. In dialysis patients, myostatin (AUC 0.79) and IL-6 (AUC 0.67) had a high discrimination value for sarcopenia, and we were able to develop a prediction model for sarcopenia, including age, albumin, adiponectin, and myostatin levels, with an AUC of 0.806 (95% CI: 0.721-0.891). Adipokines and myokines appear to be useful laboratory markers for assessing malnutrition and sarcopenia. The formula we propose could contribute to a better understanding of sarcopenia and potentially lead to more effective interventions and management strategies for dialysis patients.

Adipose tissue metabolic changes in chronic kidney disease

Adipose tissue is a complex organ whose functions go beyond being an energy reservoir to sustain proper body energy homeostasis. Functioning as an endocrine organ, the adipose tissue has an active role in the body's metabolic balance regulation through several secreted factors generally termed as adipokines. Thus, adipose tissue dysregulation in chronic kidney disease (CKD) can have a deep impact in the pathophysiology of diseases associated with metabolic dysregulation including metabolic syndrome, insulin resistance (IR), atherosclerosis, and even cachexia. CKD is a progressive disorder linked to increased morbidity and mortality. Despite being characterized by renal function loss, CKD is accompanied by metabolic disturbances such as dyslipidemia, protein energy wasting, chronic low-grade inflammation, IR, and lipid redistribution. Thus far, the mechanisms by which these changes occur and the role of adipose tissue in CKD development and progression are unclear. Further understanding of how these factors develop could have implications for the management of CKD by helping identify pharmacological targets to improve CKD outcomes.

Nutritional and Anthropometric Indices in Children Receiving Haemodiafiltration vs Conventional Haemodialysis - The HDF, Heart and Height (3H) Study

BACKGROUND

The "HDF-Heart-Height" study showed that haemodiafiltration (HDF) is associated with improved growth compared to conventional haemodialysis (HD). We report a post-hoc analysis of this study assessing the effect of extracorporeal dialysis therapies on nutritional indices.

METHODS

107 children were included in the baseline cross-sectional analysis, of whom 79 (43 HD, 36 HDF) completed the 12-month follow-up. Height (Ht), optimal 'dry' weight (Wt), and body mass index (BMI) standard deviations scores (SDS), waist-to-hip ratio, des-acyl ghrelin (DAG), adiponectin, leptin, insulin-like growth factor-1 (IGF-1)-SDS and insulin were measured.

RESULTS

The levels of nutritional indices were comparable between HDF and HD patients at baseline and 12-month. On univariable analyses Wt-SDS positively correlated with leptin and IGF-1-SDS, and negatively with DAG, while Ht-SDS of the overall cohort positively correlated with IGF1-SDS and inversely with DAG and adiponectin. On multivariable analyses, higher 12-month Ht-SDS was inversely associated with baseline DAG (beta = -0.13 per 500 higher; 95%CI -0.22, -0.04; P = .004). Higher Wt-SDS at 12-month was positively associated with HDF modality (beta = 0.47 vs HD; 95%CI 0.12-0.83; P = .01) and inversely with baseline DAG (beta = -0.18 per 500 higher; 95%CI -0.32, -0.05; P = .006). Growth Hormone (GH) treated patients receiving HDF had higher annualized increase in Ht SDS compared to those on HD.

CONCLUSIONS

In children on HD and HDF both Wt- and Ht-SDS independently correlated with lower baseline levels of the anorexygenic hormone DAG. HDF may attenuate the resistance to GH, but further studies are required to examine the mechanisms linking HDF to improved growth.

Pro-Inflammatory Profile of Adipokines in Obesity Contributes to Pathogenesis, Nutritional Disorders, and Cardiovascular Risk in Chronic Kidney Disease

Obesity is a disease which leads to the development of many other disorders. Excessive accumulation of lipids in adipose tissue (AT) leads to metabolic changes, including hypertrophy of adipocytes, macrophage migration, changes in the composition of immune cells, and impaired secretion of adipokines. Adipokines are cytokines produced by AT and greatly influence human health. Obesity and the pro-inflammatory profile of adipokines lead to the development of chronic kidney disease (CKD) through different mechanisms. In obesity and adipokine profile, there are gender differences that characterize the male gender as more susceptible to metabolic disorders accompanying obesity, including impaired renal function. The relationship between impaired adipokine secretion and renal disease is two-sided. In the developed CKD, the concentration of adipokines in the serum is additionally disturbed due to their insufficient excretion by the excretory system caused by renal pathology. Increased levels of adipokines affect the nutritional status and cardiovascular risk (CVR) of patients with CKD. This article aims to systematize the current knowledge on the influence of obesity, AT, and adipokine secretion disorders on the pathogenesis of CKD and their influence on nutritional status and CVR in patients with CKD.

The impact of uremic toxins on Alzheimer's disease

Alzheimer's disease (AD) is the most common type of dementia, pathologically characterized by accumulation of senile plaques and neurofibrillary tangles. Chronic kidney disease (CKD) is highly prevalent in elderly population closely associated with occurrence of dementia. Recent epidemiological and experimental studies suggest a potential association of CKD with AD. Both diseases share a panel of identical risk factors, such as type 2 diabetes; and hypertension. However, the relationship between CKD and AD is unclear. Lower clearance of a panel of uremic toxin including cystatin-C, guanidine, and adiponectin due to CKD is implied to contribute to AD pathogenesis. In this review we summarize the current evidence from epidemiological, experimental and clinical studies on the potential contribution of uremic toxins to AD pathogenesis. We describe outstanding questions and propose an outlook on the link between uremic toxins and AD.

Progression in Physical Frailty in Peritoneal Dialysis Patients

BACKGROUND

Physical frailty contributes to adverse clinical outcomes in peritoneal dialysis (PD) patients. Little has been reported about frailty transitions in this population. We aimed to describe the transitions of frailty in PD patients and identify factors that predicted changes in frailty state.

METHODS

In a prospective observational study, we recruited 267 PD patients. Frailty was assessed by a validated frailty score. Depression was graded by PHQ-9 score, and nutritional status was evaluated by serum albumin, Subjective Global Assessment (SGA), and comprehensive Malnutrition Inflammation Score (MIS). The primary outcome was the change in frailty score at follow-up compared to baseline.

RESULTS

At baseline, 194 (72.7%) patients were classified as frail. With time, their frailty scores significantly increased (p < 0.001), and 93 of the surviving subjects (78.2%) were classified as frail. There was a modest significant correlation between change in MIS (p < 0.001), change in SGA score (p < 0.001), and change in PHQ-9 score (p < 0.001) with change in frailty score. An increase in PHQ-9 score (p < 0.001) and MIS (p = 0.001), as well as longer duration of hospitalization (p = 0.001), was independently associated with a greater change in frailty score after adjustment for confounding factors. Frailty score was also improved in patients who were converted to hemodialysis (p = 0.048) and received renal transplantation (p = 0.005).

CONCLUSION

Our findings suggested that frailty transitions were common in PD patients. Worsening in nutrition and depression, together with a longer duration of hospitalization, were associated with worsening in frailty.

Effects of dynamic and isometric resistance training protocols on metabolic profile in hemodialysis patients: a randomized controlled trial

The aim of this study was to compare the effect of dynamic (DRT) and isometric (IRT) resistance training on glycemic homeostasis, lipid profile, and nitric oxide (NO) in hemodialysis (HD) patients. Patients were randomly distributed into 3 groups: control (n = 65), DRT (n = 65), and IRT (n = 67). Patients assessed before and after the intervention period were tested for fasting blood glucose, glycated hemoglobin, oral glucose tolerance test, insulin resistance, lipid profile, leptin, insulin, adiponectin, C-reactive protein, and NO . Patients underwent to strength and body composition assessments. Subjects allocated in both DRT and IRT groups took part in a 24-week resistance training program, 3 times per week. Each training session was approximately 1 hour before dialysis and consisted of 3 sets of 8-12 repetitions at low intensity. Total workload was higher in the DRT as compared with the IRT. This heightened workload related to better glycemic homeostasis in HD patients as measured by regulation of insulin, adiponectin, and leptin, while improveing triglycerides, free-fat mass, and muscle strength. Additionally, NO levels were increased in the DRT group. NO was significantly correlated with glucose intolerance (r = -0.42, p = 0.0155) and workload (r = 0.46, p = 0.0022). The IRT group only improved strength (p < 0.05). Twenty-four weeks of DRT improved glycemic homeostasis, lipid profile, and NO in HD patients. Although IRT seems to play an important role in increasing strength, DRT might be a better choice to promote metabolic adjustments in HD patients. Clinical trial: http://www.ensaiosclinicos.gov.br/rg/RBR-3gpg5w. Novelty: DRT might be a better choice for metabolic improvements in patients with chronic kidney disease (CKD). Exercise-training might treat metabolic imbalance in CKD patients.

Adiponectin in Chronic Kidney Disease

Adiponectin is the adipokine associated with insulin sensitization, reducing liver gluconeogenesis, and increasing fatty acid oxidation and glucose uptake. Adiponectin is present in the kidneys, mainly in the arterial endothelium and smooth muscle cells, as well as in the capillary endothelium, and might be considered as a marker of many negative factors in chronic kidney disease. The last few years have brought a rising body of evidence that adiponectin is a multipotential protein with anti-inflammatory, metabolic, anti-atherogenic, and reactive oxygen species (ROS) protective actions. Similarly, adiponectin has shown many positive and direct actions in kidney diseases, and among many kidney cells. Data from large cross-sectional and cohort studies showed a positive correlation between serum adiponectin and mortality in chronic kidney disease. This suggests a complex interaction between local adiponectin action, comorbidities, and uremic milieu. In this review we discuss the role of adiponectin in chronic kidney disease.

Effect of Long-term Peritoneal Dialysis on Change in Visceral Fat Area: A Single-Center Experience

INTRODUCTION

Visceral fat area (VFA) is known to increase after initiation of peritoneal dialysis (PD). However, the factors contributing to the increase in VFA in long-term PD patients have not been sufficiently elucidated. The present study investigated factors that affect VFA in patients who continue PD for ≥3 years.

METHODS

Twenty patients (63.1 ± 10.3 years, 9 men, 11 diabetic patients) between January 2008 and January 2015 were included. VFA, subcutaneous fat area (SFA) and waist circumference at initiation and follow-up were measured at the level of the umbilicus by computed tomography using an image analysis system. Change in VFA was defined as the value obtained by dividing VFA at the final follow-up by that at the initiation. The correlations between clinical parameters at initiation and changes in VFA were analyzed.

RESULTS

There was no significant change in body weight (57.6 ± 10.4 vs 58.3 ± 7.8 kg, P = 0.296) during the mean final follow-up period of 55 ± 13 months, although VFA increased significantly (103.6 ± 39.2 vs 122.6 ± 38.3 cm2, P = 0.030). Although subcutaneous fat area (SFA) did not change (124.7 ± 52.3 vs 124.5 ± 49.2 cm2, P = 0.989), waist circumference increased significantly (79.4 ± 8.4 vs 83.7 ± 6.9 cm, P = 0.010). SFA (r = -0.735, P < 0.001), waist circumference (r = - 0.644, P = 0.002), high-density lipoprotein cholesterol (HDL-C) (r = 0.487, P = 0.029), and age (r = 0.507, P = 0.023) correlated significantly with changes in VFA.

CONCLUSIONS

VFA might increase with long-term PD in patients with end-stage kidney disease who have high HDL-C, small SFA, and small waist circumference at initiation.

Adiponectin Levels and Atherosclerotic Risk Factors in Pediatric Chronic Peritoneal Dialysis Patients

Background

Atherosclerotic vascular diseases are the major cause of mortality in patients with end-stage renal disease (ESRD) treated with chronic peritoneal dialysis (CPD), even in children. Adiponectin (ADPN) is a recently discovered adipocyte-derived plasma protein having anti-atherogenic properties. ADPN levels are elevated in ESRD but it has been reported that ESRD patients with low plasma ADPN levels have a high risk of cardiovascular death.

Objective

To clarify the atherosclerotic risk and especially the significance of ADPN levels in pediatric patients on CPD.

Design

Cross-sectional study in the pediatric peritoneal dialysis unit of a university hospital.

Patients

18 children, aged 12.6 ± 5.6 years, being treated with CPD and 20 healthy age- and sex-matched control subjects were enrolled in this study.

Methods

Serum ADPN levels and other risk factors, including blood pressure, blood glucose, serum lipid/lipoprotein fractions, apolipoprotein B, C-reactive protein (CRP), lipoprotein(a), and homocysteine levels, were studied in CPD patients and compared to the controls.

Results

Serum ADPN levels were three times higher in the CPD group compared to the control subjects, as was previously reported. Apolipoprotein B and CRP levels were also high in the CPD group. No significant difference was found in other atherosclerotic parameters, including lipoprotein(a) and homocysteine levels. Interestingly, we found a negative correlation between log ADPN and creatinine levels among the CPD patients ( r = –0.54, p < 0.05). There was no correlation between log ADPN and duration of CPD. Creatinine and low-density lipoprotein levels could account for 54% of the total variation in ADPN levels.

Conclusion

Among pediatric CPD patients, serum levels of the anti-atherogenic protein, ADPN, were inversely associated with creatinine. ADPN level might be a novel marker to predict prognosis in pediatric CPD patients.

The association of adiponectin with metabolic syndrome and clinical outcome in patients with non-diabetic chronic kidney disease

Adiponectin is the most abundant circulating adipokine, and it has insulin-sensitizing and anti-inflammatory properties. Although it has been speculated that kidney function decline associated with elevated adiponectin is attributable to decreased renal clearance and compensatory responses to adiponectin resistance, it is unclear how elevated adiponectin affects clinical outcomes in chronic kidney disease (CKD) patients and whether the effects are the same as those in the general population. Therefore, the aim of this study is to examine whether the association between serum adiponectin levels and clinical outcomes in non-diabetic CKD patients is independent of adiposity and metabolic syndrome. We enrolled 196 non-diabetic CKD patients with eGFR ranging between 10 and 60 mL/min/1.73 m2, these patients were divided into two groups based on the presence of metabolic syndrome. The primary endpoint was all-cause mortality or renal events (renal failure requiring renal replacement therapy [RRT] or 50% reduction in eGFR). During the mean follow-up period of 5 years, 48 (24.5%) incident cases of end-stage renal disease (ESRD) were observed, and 33 (16.8%) deaths occurred. The mean eGFR was 29.8 ± 12.8 mL/min/1.73m2. The baseline median adiponectin concentration in the cohort was 29.4(interquartile range, 13.3-108.7) μg/ml. Adiponectin levels were inversely related to body mass index (BMI) (r = -0.29; P < 0.001) and waist circumference (r = -0.35; P < 0.001). In the fully adjusted Cox regression model, the hazard ratios (HRs) were 2.08 (95% confidence interval [CI], 1.08-4.02; P = 0.03) for RRT and 1.66 (95% CI, 1.03-2.65; P = 0.04) for composite renal outcome. The risks remained consistent within different subgroups. However, no association was observed with mortality risk. In conclusion, higher adiponectin levels are associated with a higher risk of ESRD independent of conventional risk factors, BMI, and metabolic syndrome components.

Adiponectin Receptor gene Polymorphisms are Associated with Kidney Function in Elderly Japanese Populations

Aim: Adiponectin exhibits its biological effects through adiponectin receptors (AdipoR1 and AdipoR2), which are distributed in the kidneys, and activation of those receptors could prevent or ameliorate diabetic nephropathy. This study aimed to evaluate the associations between AdipoR single nucleotide polymorphisms (SNPs) and kidney function in an elderly Japanese population.

Methods: A total of 271 elderly Japanese volunteers underwent anthropometric and laboratory tests (cystatin C-based eGFR and total and high molecular weight adiponectin levels at baseline and a follow-up visit). Genotype data were obtained for the selected 7 and 5 AdipoR1 and AdipoR2 SNPs, respectively.

Results: In a cross-sectional analysis at baseline, we found a significant association between the AdipoR2 SNP rs12230440 and kidney function; eGFRcys tended to increase as the number of carriers of T alleles increased after adjustment for covariates and Bonferroni correction, although the association of the SNP and annual eGFR decline could not be identified in the longitudinal data. Regarding the variants rs16850797, rs11061925, and rs10773983, each of the allele G, allele C, and allele G showed nominally significant associations with higher eGFRcys. However, this failed to reach significance after Bonferroni correction.

Conclusion: Here, an AdipoR2 SNP was associated with kidney function, suggesting that the effects of this polymorphism on adiponectin receptor may affect kidney function in the elderly Japanese population.

Adiponectin is not associated with renal function decline in community-dwelling elderly adults

Adiponectin secreted by adipocytes plays an important role in the regulation of glucose and fatty acid metabolism. Contrary to findings in patients with chronic kidney disease (CKD), no prospective data about the association of serum adiponectin with renal function decline in the general population have yet appeared. Our objective was to analyze the relationship of total and high molecular weight (HMW) adiponectin with renal function decline as measured by cystatin C in community-dwelling elderly adults without moderate or severe CKD.In a prospective observational analysis, a total of 216 healthy elderly volunteers with eGFRcys ≥60 mL/min/1.73 m underwent anthropometric and laboratory tests at baseline and at follow-up visits. A subgroup with serum samples collected 5 years apart was further analyzed.There were no differences in either total or HMW adiponectin level between subjects subsequently undergoing rapid renal function decline and subjects with normal physiologic renal function decline (P = .71, P = .81). On univariate linear regression, neither total nor HMW adiponectin were associated with annual renal function decline (β = -0.23; P = .71, β = -0.057; P = .90). Multivariate analysis did not show a significant contribution of either total or HMW adiponectin to annual renal function decline (β = -0.50; P = .46, β = 0.01; P = .98). In the logistic regression analysis, we did not observe any statistically significant association of serum adiponectin levels with rapid renal function decline or incidence of CKD.Contrary to findings in populations with CKD, neither total nor HMW adiponectin had a substantial association with renal function decline in an elderly population with eGFRcys ≥60 mL/min/1.73 m. Our results and conclusions should not be extrapolated to subjects with other characteristics.

Inflammation and Peritoneal Dialysis

Inflammation is one of the well-recognized nontraditional risk factors that contributes to the excessive cardiovascular mortality in peritoneal dialysis (PD) patients. Serum C-reactive protein and interleukin-6 levels are common surrogate markers used to measure inflammatory burden and predict adverse clinical outcomes in PD patients. Causes of inflammation are complex and can be categorized into factors related to a decrease in renal function and factors related to dialysis. They interact with each other and finally result in systemic and intraperitoneal inflammation. This review discusses the various causes and clinical implications of inflammation in PD patients. More importantly, potential therapeutic options that target the underlying pathogenic mechanisms are explored.

High serum adiponectin is associated with anemia development in chronic kidney disease: The results from the KNOW-CKD study

BACKGROUND

Adiponectin is an adipokine secreted by adipocytes. A low adiponectin level is a significant risk factor of diabetes mellitus and cardiovascular disease. Recent studies have shown that adiponectin is negatively associated with hematopoiesis and predicts the development of anemia in the general population. In chronic kidney disease (CKD) patients, circulating adiponectin level is paradoxically elevated and the role of adiponectin is complex. Therefore, we evaluated the relationship between adiponectin and anemia in these patients.

METHODS

This prospective longitudinal study included 2113 patients from the KNOW-CKD study (KoreaN cohort study for Outcome in patients With CKD), after excluding 125 without data on adiponectin levels. Hemoglobin levels were measured yearly during a mean follow-up period of 23.7 months. Anemia was defined as hemoglobin levels of <13.0 and 12.0 g/dL for men and women, respectively.

RESULTS

Mean patient age was 53.6 ± 12.2 years, and 1289 (61%) were men. The mean estimated glomerular filtration rate (eGFR) was 50.4 ± 30.2 mL min^-1 1.73 m^-2. Serum adiponectin level was inversely associated with body mass index, eGFR, log-transformed C-reactive protein, and positively with Charlson comorbidity index, urine protein to creatinine ratio, and high density lipoprotein cholesterol. In addition, serum adiponectin level was also negatively correlated with hemoglobin level and reticulocyte production index in both men and women. In multivariable linear regression analysis after adjustment of multiple confounders, adiponectin was negatively associated with hemoglobin (men, β = -0.219, P < .001; women, β = -0.09, P = .025). Among 1227 patients without anemia at baseline, 307 newly developed anemia during the follow-up period. In multivariable Cox regression analysis after adjustment of confounders, high adiponectin level was significantly associated with an increased risk of incident anemia (per 1 µg/mL increase, hazard ratio, 1.02; 95% confidence interval 1.01-1.04; P = .001).

CONCLUSIONS

A high serum adiponectin level is independently associated with a low hemoglobin level and predicts the development of anemia in patients with CKD. These findings reveal the potential role of adiponectin in CKD-related anemia.

The 24-Month Changes in Body Fat Mass and Adipokines in Patients Starting Peritoneal Dialysis

♦ BACKGROUND: Peritoneal dialysis (PD) is characterized by a gain in fat mass. The fat tissue is a complex endocrine organ that releases various adipokines. In this study, we prospectively examined serial changes of fat composition and adipokines in patients undergoing PD. ♦ METHODS: Body composition was assessed by computed tomography (CT). Nutrition status and adipokines (leptin, adiponectin, interleukin [IL]-6, and tumor necrosis factor [TNF]-α) were assessed on the 7th day and 6 months, 12 months, and 24 months after the start of PD. ♦ RESULTS: Fifty-four patients (28 men), with a mean age of 53.2 ± 13.2 years, were enrolled. Baseline fat mass, especially subcutaneous fat mass, was correlated with baseline leptin (ρ = 0.612), adiponetin (ρ = -0.477), and interleukin-6 (IL-6) (ρ = 0.391). Visceral fat mass was correlated with leptin (ρ = 0.545) and adiponectin (ρ = -0.514). Baseline adiponectin was negatively correlated with baseline leptin (ρ = -0.363). While body weight and leptin increased during the 24 months, serum adiponectin decreased in that period. The changes in visceral and subcutaneous fat mass were greater in the first 12 months and 6 months, respectively. There was no difference in IL-6 and TNF-α. Eight patients died during the follow-up period (mean 47.4 months). Twenty-seven patients continued PD. Increased baseline and serial change of IL-6 level were risk factors for mortality. After adjusting for age, sex, diabetes mellitus (DM), and coronary vascular disease (CVD), the significance of the IL-6 level disappeared. ♦ CONCLUSIONS: Baseline subcutaneous fat in patients starting PD is correlated with baseline adipokine levels rather than visceral fat. The increase in subcutaneous fat was greatest in the first 6 months. While leptin and adiponectin increased and decreased respectively, IL-6 did not change in the first 24 months.

The effect of vitamin D administration on serum leptin and adiponectin levels in end-stage renal disease patients on hemodialysis with vitamin D deficiency: A placebo-controlled double-blind clinical trial

BACKGROUND

The prevalence of vitamin D deficiency is higher in end-stage renal disease (ESRD) patients compared to healthy populations. This deficiency could lead to several complications with different mechanisms and might result in reduced survival in patients. Leptin and adiponectin are messenger proteins with endocrine secretion from adipocytes and various effects in cellular mechanisms. The goal of this study was to find the effect of vitamin D administration on serum levels of leptin and adiponectin in ESRD patients.

MATERIALS AND METHODS

This double-blind randomized placebo-controlled clinical trial was carried out on 64 ESRD patients on hemodialysis in the Amin and Noor hospitals of Isfahan, Iran. Patients were categorized into two groups, on control and intervention; serum levels of vitamin D, leptin, and adiponectin were measured in both groups before and after the study. The intervention group was treated with vitamin D pearls, while the control group received placebo in the same manner.

RESULTS

The mean [standard deviation (SD)] ages of the patients were 62 (21) years and 60 (19) years in the control and treated groups, respectively.

CONCLUSION

The change in serum level of vitamin D was statistically significant in the treatment group but not in the control group. The serum level of leptin was reduced in the treatment group, while the serum level of adiponectin increased significantly, but none of these changes were statistically significant in the control group. This study showed that vitamin D administration is associated with an increase in adiponectin and a decrease in leptin level in ESRD patients.

Association of Adiponectin with High-Sensitivity C-Reactive Protein and Clinical Outcomes in Peritoneal Dialysis Patients: A 3.5-Year Follow-Up Study

Introduction

Adiponectin (ADPN), one of most abundant fat-derived biologically active substances, plays an important role in anti-atherosclerotic process. There are conflicting results about the impact of ADPN on cardiovascular (CV) outcomes and mortality, particularly in patients undergoing peritoneal dialysis (PD). Moreover, the relationship between ADPN and inflammatory mediators has been seldom explored in this population. Therefore, we examined the relationship between ADPN and longitudinal high-sensitivity C-reactive protein (hs-CRP) changes and investigated whether ADPN or hs-CRP levels could predict CV outcomes and mortality in prevalent PD patients after comprehensive adjustment of possible confounders.

Methods

In this prospective cohort study, 78 PD patients were enrolled and followed from February 2009 to August 2012. During follow-up, CV events and all-cause mortality were recorded.

Results

The mean baseline ADPN value was 29.46±18.01 μg/ml and duration of PD treatment was 37.76±36.96 months. In multiple linear regression analysis, plasma ADPN levels positively correlated with high-density lipoprotein and negatively associated with hs-CRP, body mass index, D4/D0 glucose, triglyceride, and duration of PD treatment. After stratified by genders, the inverse association between baseline ADPN and hs-CRP was more significant in the female group. The hs-CRP levels were followed up annually and remained significantly lower in the high ADPN group in the first 2 years. Patients were then stratified into two groups according to the median ADPN value (23.8 μg/ml). The results of Kaplan-Meier survival analysis demonstrated less CV events and better survival in high ADPN group. On multivariate Cox regression analysis, only ADPN level (HR: 0.93, 95% CI: 0.88–0.98, p = 0.02), age and history of CV diseases were independent risk factors for future CV events. Furthermore, hs-CRP (HR: 1.11, 95% CI:1.001–1.22, p = 0.04) was identified as independent predictor of all-cause mortality.

Conclusions

Serum hs-CRP levels were consistently lower in the high ADPN group during 2-year follow-up. We also demonstrated the importance of ADPN and hs-CRP in predicting CV events and all-cause mortality in PD population during 3.5-year follow-up.

Association of Adiponectin With Body Composition and Mortality in Hemodialysis Patients

BACKGROUND

In the general population, circulating adiponectin is associated with a favorable cardiovascular risk profile (eg, lower triglycerides and body fat) and decreased mortality. Hemodialysis (HD) patients have comparatively higher adiponectin concentrations, but prior studies examining the adiponectin-mortality association in this population have not accounted for body composition or shown a consistent relationship.

STUDY DESIGN

Prospective cohort study.

SETTINGS & PARTICIPANTS

We examined baseline serum adiponectin concentrations in 501 HD patients across 13 dialysis centers from the prospective MADRAD (Malnutrition, Diet, and Racial Disparities in Chronic Kidney Disease) cohort (entry period, October 2011 to February 2013; follow-up through August 2013).

PREDICTOR

Serum adiponectin concentration in tertiles (tertiles 1, 2, and 3 defined as ≤16.1, >16.1-<30.1, and ≥30.1-100.0 μg/mL, respectively). Adjustment variables included case-mix and laboratory test results (age, sex, race, ethnicity, vintage, diabetes, serum albumin, total iron-binding capacity, serum creatinine, white blood cell count, phosphate, hemoglobin, and normalized protein catabolic rate), body composition surrogates (subcutaneous, visceral, and total-body fat and lean body mass), and serum lipid levels (cholesterol, high-density lipoprotein cholesterol, and triglycerides).

OUTCOMES

All-cause mortality using survival (Cox) models incrementally adjusted for case-mix and laboratory test results.

RESULTS

Among 501 HD patients, 50 deaths were observed during 631.1 person-years of follow-up. In case-mix- and laboratory-adjusted Cox analyses, the highest adiponectin tertile was associated with increased mortality versus the lowest tertile (HR, 3.35; 95% CI, 1.50-7.47). These associations were robust in analyses that additionally accounted for body composition (HR, 3.18; 95% CI, 1.61-8.24) and lipid levels (HR, 3.64; 95% CI, 1.34-7.58).

LIMITATIONS

Residual confounding cannot be excluded.

CONCLUSIONS

Higher adiponectin level is associated with a 3-fold higher death risk in HD patients independent of body composition and lipid levels. Future studies are needed to elucidate underlying mechanisms and determine therapeutic targets associated with improved outcomes in HD patients.

Adipokines in peritoneal dialysis: relevant clinical impact according to body composition

Adipokines impact on clinical outcomes is not adequately addressed in peritoneal dialysis (PD). We investigated the impact of leptin/adiponectin ratio (L/A) as a predictor of cardiovascular events (CVE) in PD, taking into consideration patient's body composition and the potential role of glucose load. We prospectively followed 66 prevalent PD patients for 47.0 ± 28.2 months. New CVE were evaluated. Lean tissue index (LTI), relative fat mass (relFM) and relative overhydration (relOH) using multifrequency bioimpedance (BCM) were assessed; serum lipids, interleukin-6 (IL-6), leptin and adiponectin were measured. We established the determinants of L/A using multiple linear regression and the impact of L/A on CVE. Obesity was present in 47 (73.4%) patients according to relFM, and in seven (10.6%) according to body mass index (BMI). Leptin and L/A exhibited a stronger correlation with relFM (both r = 0.62, P < 0.0001) than with BMI (r = 0.46 and r = 0.51, respectively, both P < 0.0001). L/A showed a significant correlation with triglycerides (r = 0.41, P = 0.001) and HDL-cholesterol (r = -0.358, P = 0.003), better than isolated leptin or adiponectin. RelFM (RR = 0.130, 95%confidence interval [CI]:0.086-0.174, P < 0.0001) and LTI (RR = 0.194, 95%CI:0.037-0.351, P = 0.016) were independent predictors of L/A (R(2) = 0.67). Patients who suffered new CVE were older (59.12 ± 12.41 vs. 47.52 ± 13.84years, P = 0.003) and had a higher relOH (11.28 ± 7.29 vs. 6.60 ± 8.16%, P = 0.028). L/A was significantly higher in patients with CVE[2.29 (1.79) vs. 0.65 (1.73), P = 0.028] but this association was only put on evidence after excluding patients with wasting. BMI is an inaccurate method to classify obesity in PD since it underestimates its prevalence compared with body composition assessment using BCM. High adiponectin and low leptin are associated with a more favorable metabolic risk profile in peritoneal dialysis. The L/A is determined by relFM and by LTI. A higher L/A is associated with CVE in PD patients without wasting.

A longitudinal study of nutritional and inflammatory status in patients on dialysis

OBJECTIVE

Several anthropometric, laboratory and bioelectrical impedance parameters of nutritional status and inflammation are often used as prognostic indices in patients on dialysis. Their longitudinal assessment is necessary for the estimation of their true prognostic value. We aim to estimate this prognostic value in better-nourished dialysis patients, which are commonly under-represented in pertinent studies.

METHODS

The design is a prospective case series. Pertinent parameters were studied three times during a 20-month period in 47 haemodialysis (HD) and 27 peritoneal dialysis (PD) patients with a low malnutrition-inflammation score (MIS). Mortality rate was assessed three years after the initial evaluation. Correlation coefficients were calculated between mortality rate, the studied parameters and their alteration.

RESULTS

Serum albumin of less than 40 g/l was strongly correlated with mortality risk. The alteration of studied parameters during a short period of time does not allow for long-term prediction of mortality risk.

CONCLUSION

Serum albumin had the strongest predictive value of all the pertinent parameters in the study. Thus, better conjugate clinical and laboratory measurements should be developed for patients on PD, as well as for those with a relatively low MIS.

Accumulation of epicardial fat rather than visceral fat is an independent risk factor for left ventricular diastolic dysfunction in patients undergoing peritoneal dialysis

BACKGROUND

Symptoms of heart failure with preserved left ventricular systolic function are common among patients undergoing peritoneal dialysis (PD). Epicardial fat (EpF) is an ectopic fat depot with possible paracrine or mechanical effects on myocardial function. The aim of our current study is to assess the association between EpF and Left ventricular diastolic dysfunction (LVDD) in patients undergoing PD and to clarify the relationships among EpF, inflammation, and LVDD in this population.

METHODS

This was a cross-sectional study of 149 patients with preserved left ventricular systolic function who were undergoing PD. LVDD was diagnosed (according to the European Society of Cardiology guidelines) and EpF thickness measured by echocardiography. The patients without LVDD were used as controls. The serum inflammatory biomarker high-sensitivity C-reactive protein (hsCRP) was measured. The location and amount of adipose tissue were assessed by computed tomography (CT) at the level of the fourth lumbar vertebra.

RESULTS

Subjects with LVDD had higher levels of hsCRP, more visceral and peritoneal fat, and thicker EpF (all p < 0.001) than controls. Visceral adipose tissue, hsCRP, and EpF all correlated significantly (p < 0.05) with LVDD. Multivariate regression analysis rendered the relationship between visceral adipose tissue and LVDD insignificant, whereas EpF was the most powerful determinant of LVDD (odds ratio = 2.41, 95% confidence interval = 1.43-4.08, p < 0.01). EpF thickness also correlated significantly with the ratio of transmitral Doppler early filling velocity to tissue Doppler early diastolic mitral annular velocity (E/e'; r = 0.27, p < 0.01).

CONCLUSION

EpF thickness is significantly independently associated with LVDD in patients undergoing PD and may be involved in its pathogenesis.

Metabolic syndrome and abdominal fat are associated with inflammation, but not with clinical outcomes, in peritoneal dialysis patients

Background

In the general population, metabolic syndrome (MetS) is correlated with visceral fat and a risk factor for cardiovascular disease (CVD); however, little is known about the significance of abdominal fat and its association with inflammation and medication use in peritoneal dialysis (PD) patients. We investigated the relationship of visceral fat area (VFA) with C-reactive protein (CRP) levels and medication use in PD patients and followed their clinical outcomes.

Methods

In a prospective study from February 2009 to February 2012, we assessed diabetes mellitus (DM) status, clinical and PD-associated characteristics, medication use, CRP levels, components of MetS, and VFA in 183 PD patients. These patients were categorized into 3 groups based on MetS and DM status: non-MetS (group 1, n = 73), MetS (group 2, n = 65), and DM (group 3, n = 45). VFA was evaluated by computed tomography (CT) and corrected for body mass index (BMI).

Results

Patients in group 1 had smaller VFAs than patients in groups 2 and 3 (3.2 ± 1.8, 4.6 ± 1.9, and 4.9 ± 2.0 cm²/[kg/m²], respectively, P < 0.05) and lower CRP levels (0.97 ± 2.31, 1.27 ± 2.57, and 1.11 ± 1.35 mg/dL, respectively, P < 0.05). VFA increased with the number of criteria met for MetS. After adjusting for age, body weight, and sex, CRP and albumin levels functioned as independent positive predictors of VFA; on other hand, the use of renin-angiotensin system blockers was inversely correlated with VFA in PD patients without DM. In the survival analysis, DM patients (group 3) had the poorest survival among the 3 groups, but no significant differences were found between groups 1 and 2.

Conclusion

This study showed that VFA and MetS are associated with CRP levels but cannot predict survival in PD patients without DM. The complex relationship of nutritional parameters to VFA and MetS may explain these results. The type of antihypertensive medication used was also associated with the VFA. The mechanisms behind these findings warrant further investigation.

Adiponectin in renal disease--a review of the evidence as a risk factor for cardiovascular and all-cause mortality

Adiponectin, an adipokine, was discovered in 1995. The initial evidence led to the study of adiponectin as a determinant of insulin sensitivity and blood glucose levels. The literature then evolved to reports of the inverse association of adiponectin with incident Type 2 diabetes mellitus and coronary heart disease. Shortly thereafter, reports of a positive association with heart failure and mortality appeared and were replicated. We review here the basic science evidence and clinical studies of the role of renal function and kidney disease as a determinant of adiponectin.

Vitamin D deficiency, insulin resistance, serum adipokine, and leptin levels in peritoneal dialysis patients

OBJECTIVE

Associations between 25 hydroxy vitamin D [25(OH)D], adipokines levels, and insulin resistance have been reported. The aim of this study was to explore the effects of cholecalciferol supplementation on vitamin D levels, insulin resistance, leptin, and adiponectin levels in vitamin D-deficient peritoneal dialysis (PD) patients.

METHODS

In nineteen vitamin D-deficient PD patients, who were treated with cholecalciferol, fasting serum glucose, insulin, adiponectin, leptin, 25(OH)D and parathyroid hormone (PTH) were measured before and after cholecalciferol replacement therapy. Eighteen (94.7 %) PD patients with vitamin D deficiency were receiving active vitamin D compounds (alphacalciferol) for PTH control. Alphacalciferol dosing was kept constant during treatment with cholecalciferol.

RESULTS

While mean 25(OH)D significantly increased from (10.2 ± 4.9 ng/ml) to (82.9 ± 56.5 ng/ml) (p < 0.05), mean homeostatic model assessment-insulin resistance index significantly decreased from (4.6 ± 3.6) to (2.8 ± 2.0) after cholecalciferol replacement therapy (p < 0.05). Serum leptin levels (12.9 ± 17.6 ng/ml) significantly increased (18.1 ± 19.5 ng/ml) (p < 0.05), while there was no change in serum adiponectin, calcium, and phosphate after vitamin D replacement. Serum PTH levels significantly decreased from 551.9 ± 276.6 pg/ml to 434.0 ± 273.4 ng/ml.

CONCLUSIONS

Cholecalciferol replacement therapy significantly decreases PTH levels and insulin resistance. The results of this study need to be confirmed in larger clinical trials.

Waist circumference as a predictor of adiponectin levels in peritoneal dialysis patients: a 12-month follow-up study

OBJECTIVES

This prospective study, conducted at the dialysis unit of the Nephrology Division, Federal University of Sao Paulo-Oswaldo Ramos Foundation, Brazil, aimed to evaluate whether waist circumference (WC) can predict adiponectin levels in patients undergoing peritoneal dialysis (PD).

METHODS

Among 115 patients on PD at a single dialysis center who were evaluated at 6 and 12 months, 57% were men, 31% had diabetes, mean age was 52.8 ± 16.1 years, body mass index was 25 ± 4.3 kg/m(2), and dialysis vintage was 13 months (range: 5 - 33 months). We measured WC at the umbilicus level. Adiponectin was determined by an enzyme-linked immunosorbent assay.

RESULTS

At baseline, WC was inversely associated with adiponectin (r = -0.48, p < 0.01). After adjustment for sex, age, diabetes, peritoneal clearance, and residual renal function, WC was an independent determinant of serum adiponectin (β = -0.52; 95% confidence interval: -0.73 to -0.31; p < 0.001). In the prospective analysis, after adjustment for confounders, changes in WC predicted changes in adiponectin. For each unit increase in WC, adiponectin declined by 0.39 mg/L (p < 0.001).

CONCLUSIONS

This study demonstrates that WC is associated with adiponectin and, more importantly, that this simple marker of central adiposity was able to predict changes in adiponectin levels over time.

Adiponectin and atherosclerosis risk factors in African hemodialysis patients: a population at low risk for atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular disease (CVD) is the major cause of morbidity and mortality in hemodialysis (HD) patients. Adiponectin (ADPN), a recently discovered collagen-like protein, is secreted exclusively by adipocytes. It has anti-atherogenic properties and reduced serum ADPN levels have been shown to be predictive of cardiovascular events. In this study, we determined the atherosclerotic risk and the significance of ADPN levels in our HD patients and also examined its relationship to other traditional CVD risk factors. A cross-sectional study of 84 patients on maintenance HD (58 Blacks and 26 non-Blacks) and 63 healthy controls matched for age, sex and race (35 Blacks and 28 non-Blacks) was undertaken. Serum ADPN levels and other risk factors, including blood pressure, serum lipid, and C-reactive protein, were studied in HD patients and were compared with the controls. Carotid artery intima-media thickness and plaque occurrence was measured by B-mode ultrasonography while echocardiography was done according to American Society of Echocardiography guidelines. Serum ADPN levels were higher in the HD group compared with the control subjects (22.19 ± 0.98 mg/mL vs. 9.93 ± 0.68 mg/mL; P < 0.001). Higher ADPN levels in HD patients were associated with lower triglyceride levels. ADPN correlated positively (r = 0.49, P < 0.0001) with left ventricular mass index (LVMI) in the total study population. ADPN levels were raised in HD patients and correlated with LVMI, possibly because of the confounding effect of low glomerular filtration rate. ADPN levels were inversely related to risk factors for atherosclerosis and may provide possible targets for therapeutic interventions.

A combination of biocompatible peritoneal dialysis solutions and residual renal function, peritoneal transport, and inflammation markers: a randomized clinical trial

BACKGROUND

The benefits of biocompatible peritoneal dialysis (PD) fluids, particularly for residual renal function (RRF), are controversial. Moreover, the clinical effects of a PD regimen consisting of different biocompatible PD fluids have not been fully established.

STUDY DESIGN

Prospective, randomized, controlled, open-label study.

SETTING & PARTICIPANTS

Patients with end-stage kidney disease newly started on continuous ambulatory PD therapy (N = 150).

INTERVENTION

A 12-month intervention with 3 biocompatible PD fluids (a neutral-pH, low glucose degradation product, 1.5% glucose solution; a solution with 1.1% amino acid; and a fluid with 7.5% icodextrin) or conventional PD fluid.

OUTCOMES

The primary outcome was change in RRF and daily urine volume. Secondary outcomes were peritoneal transport and inflammation markers.

MEASUREMENTS

RRF, daily urine volume, serum and dialysate cytokine levels.

RESULTS

RRF(3.24 ± 1.98 vs 2.88 ± 2.43 mL/min/1.73 m(2); P = 0.9) and rate of decline in RRF (-0.76 ± 1.77 vs -0.91 ± 1.92 mL/min/1.73 m(2) per year; P = 0.6) did not differ between the biocompatible- and conventional-PD-fluid groups. However, patients using the biocompatible PD fluids had better preservation of daily urine volume (959 ± 515 vs 798 ± 615 mL/d in the conventional group, P = 0.02 by comparison of difference in overall change by repeated-measures analysis of variance). Their dialysate-plasma creatinine ratio at 4 hours was higher at 12 months (0.78 ± 0.13 vs 0.68 ± 0.12; P = 0.01 for comparison of the difference in overall change by repeated-measures analysis of variance). They also had significantly higher serum levels of adiponectin and overnight spent dialysate levels of cancer antigen 125, adiponectin, and interleukin 6 (IL-6). No differences between the 2 groups were observed for serum C-reactive protein and IL-6 levels.

LIMITATIONS

Unblinded, relatively short follow-up; no formal sample-size calculations.

CONCLUSIONS

Use of a combination of 3 biocompatible PD fluids for 12 months compared with conventional PD fluid did not affect RRF, but was associated with better preservation of daily urine volume. The biocompatible PD fluids also lead to changes in small-solute transport and an increase in dialysate cancer antigen 125, IL-6, adiponectin, and systemic adiponectin levels, but have no effect on systemic inflammatory response. The clinical significance of these changes, while of great interest, remains to be determined by further studies.

Low circulating adiponectin levels are associated with insulin resistance in non-obese peritoneal dialysis patients

In patients with end-stage renal disease (ESRD), circulating adipokine levels are increased due to decreased renal clearance, irrespective of obesity. However, whether adipokines play a role in the development of insulin resistance (IR) in non-obese ESRD patients is unknown. We conducted a cross-sectional study to identify factors associated with IR in 62 non-obese patients on peritoneal dialysis (PD). Non-obesity was defined as body mass index (BMI) <25 kg/m(2). IR was determined using homeostatic model assessment-IR (HOMA-IR). We also measured serum concentrations of adiponectin, leptin, resistin, high-sensitivity C-reactive protein (hsCRP), and IL-6. The average BMI of the study patients was 21.6 kg/m(2). When patients were divided into two groups according to the median value of HOMA-IR, serum adiponectin levels were significantly lower in patients with HOMA-IR > 1.85 than in those with HOMA-IR ≤1.85, whereas serum concentrations of leptin and resistin did not differ between the two groups. In addition, log-transformed HOMA-IR was negatively correlated with adiponectin (γ = -0.464, P < 0.001) and log-transformed high-density lipoprotein cholesterol (γ = -0.250, P = 0.050) and positively correlated with age (γ = 0.334, P = 0.008) and triglyceride (γ = 0.392, P = 0.002). However, resistin, log-transformed leptin and log-transformed hsCRP were not associated with HOMA-IR. In a multiple linear regression model, adiponectin was independently associated with HOMA-IR (β = -0.023, P = 0.015). In conclusion, this study suggests that low circulating adiponectin levels might be involved in IR even in non-obese patients undergoing PD.

Relationship of insulin resistance in chronic haemodialysis patients with inflammatory indicators, malnutrition, echocardiographic parameters and 24 hour ambulatory blood pressure monitoring

OBJECTIVE

The relationship between malnutrition, echocardiographic parameters, 24 h ambulatory blood pressure (ABP) parameters and decreased insulin sensitivity index (ISI-S) in chronic haemodialysis patients was investigated.

MATERIAL AND METHODS

ISI-S and inflammatory indicators were measured. The nutritional state was assessed by malnutrition score. Echocardiography and 24 h ABP were performed 1 day before the second haemodialysis session of the week.

RESULTS

ISI-S was inversely correlated with the night-time mean blood pressure (BP)/day-time mean BP ratio (p = 0.021) and malnutrition score (p < 0.01). High-sensitivity C-reactive protein, night-time mean BP/day-time mean BP and vena cava collapse index were independent risk factors affecting ISI-S (p < 0.001; beta = 0.412, p = 0.025; beta = -0.204, p < 0.001; beta = -0.465).

CONCLUSIONS

The decrease in ISI-S along with the hypervolaemia suggests that volume overload is a contributory factor in the pathogenesis of insulin resistance in patients with chronic renal failure. This study indicates that, in addition to the traditional cardiovascular risk factors in these patients, insulin resistance can be regarded as a risk factor, but not an independent one, mainly a reflection of the underlying culprit, hypervolaemia.

The proportion and metabolic effects of adiponectin multimeric isoforms in patients with chronic kidney disease on maintenance hemodialysis

Adiponectin circulates at least in three major forms of oligomeric complexes in plasma: a low-molecular-weight (LMW) trimer, a middle-molecular-weight (MMW) hexamer, and high-molecular-weight (HMW) adiponectin. Although it has been reported that adiponectin has the favorable metabolic properties for humans, the roles of these multimers in the patients with the end-stage renal disease (ESRD) were unidentified. We determined the level of total and multimeric adiponectin in 71 patients with nondiabetic ESRD treated with hemodialysis (HD) using a commercially available kit of enzyme-linked immunosorbent assay (ELISA). Correlations between metabolic variables and total and multimeric adiponectin were examined by Spearman's correlations analysis. Forward stepwise multiple linear regression analysis was also performed to determine the factors independently associated with them. Female patients had significantly higher total, HMW, and MMW levels than male patients did. According to homeostasis model of assessment of insulin resistance (HOMA-IR), value was associated not only with HMW but also with MMW and LMW. In multivariate analyses, HMW showed independently and positively associated with high-density lipoprotein cholesterol (HDL-C), body mass index (BMI), and sex as total adiponectin did. Unexpectedly, LMW adiponectin was independently and negatively correlated with TG and high-sensitive C-reactive protein (hs-CRP). Not only HMW adiponectin but also LMW adiponectin track with favorable metabolic effects in the patient with the ESRD.

Glucose-based peritoneal dialysis solution suppresses adiponectin synthesis through oxidative stress in an experimental model of peritoneal dialysis

OBJECTIVE

Accumulation of visceral fat is one of the major risk factors for the development of cardiovascular disease in peritoneal dialysis (PD) patients. Adiponectin, an adipokine commonly regarded as a negative indicator of metabolic disease, is reported to be downregulated in its gene level in end-stage renal disease patients. Since excessive fat deposit is involved in increased reactive oxygen species (ROS), PD solution (PDS) may contribute to ROS production, resulting in dysregulation of adiponectin. In this study, we tested our hypothesis that oxidative stress induced by PDS may play a role in the regulation of adiponectin.

METHODS

Commercial PDS containing 3.86% glucose (20 - 30 mL) was administered to SD rats for 12 weeks with and without N-acetylcysteine (NAC; 10 mmol/L). ELISA was used to quantify adiponectin in plasma and spent dialysate. For in vitro studies, fully differentiated 3T3-L1 adipocytes and adipocytes isolated from abdominal fat were treated with a high glucose solution, PDS, and H(2)O(2). Adiponectin levels in the conditioned media were measured by ELISA and immunoblot assays. The mRNA levels of adiponectin in mature adipocytes were examined using real-time RT-PCR.

RESULTS

The levels of adiponectin in plasma and spent dialysate were significantly downregulated by PDS and this effect was suppressed by NAC. In 3T3-L1 adipocytes, adiponectin secretion was inhibited by 50 mmol/L glucose, PDS diluted 2-fold, and H(2)O(2) (200 μmol/L). In addition, H(2)O(2) downregulated expression of adiponectin mRNA and secretion of adiponectin oligomer complexes.

CONCLUSIONS

Our data suggest that ROS induced by conventional glucose-based PDS may contribute to pathophysiological changes in abdominal fat and downregulate adiponectin secreted from adipocytes during long-term PD.

Serum high molecular weight adiponectin is associated with mild renal dysfunction in Japanese adults

AIMS

Renal dysfunction is a major public health problem, but there have been few investigations of the relationship between serum high molecular weight (HMW) adiponectin and renal function in Japanese community-dwelling adults.

METHODS

We randomly recruited a sample of 1,849 adult Japanese (793 men aged 60 ± 14 (mean ± standard deviation; range, 20-89) years and 1,056 women aged 62 ± 12 (range, 21-88) years) during their annual health examination in a single community. Participants with an eGFR of ≥ 60 mL/min/1.73 m² were divided into four groups based on quartiles of serum HMW adiponectin levels, and it was investigated whether serum HMW adiponectin is independently associated with eGFR.

RESULTS

Mean eGFR was significantly higher in the highest quartile than the lowest quartile of serum HMW adiponectin levels. Stepwise multiple linear regression analysis using eGFR as an objective variable, adjusted for confounding factors as explanatory variables, showed that serum HMW adiponectin (β=0.068) as well as age (β=-0.361), prevalence of antihypertensive medication (β=-0.115), triglycerides (β=-0.063), low-density lipoprotein cholesterol (β=-0.094), and fasting plasma glucose (β=0.148) were independently associated with eGFR. The multivariate-adjusted odds ratio for mild renal dysfunction of an eGFR < 70 mL/min/1.73 m² was 0.62 (95% CI, 0.42-0.91) for the highest quartile compared with participants with the lowest serum adiponectin quartile.

CONCLUSIONS

We conclude that a higher serum HMW adiponectin level is associated with a reduced odds ratio of mild renal dysfunction in Japanese adults.

Changes in body fat mass in patients after starting peritoneal dialysis

BACKGROUND

Peritoneal dialysis (PD) is characterized by gain in fat mass. Visceral fat mass is associated with metabolic syndrome and atherosclerosis rather than subcutaneous fat mass. In addition, the change in visceral fat mass is a more reliable predictor of survival in PD patients. In this study, we prospectively examined serial changes in fat composition and nutritional status and analyzed factors associated with gain in fat mass in patients undergoing PD.

METHODS

Body composition was assessed by bioelectric impedance analysis (BIA) and computed tomogram (CT). Nutrition status was assessed by Subjective Global Assessment (SGA), protein equivalent of nitrogen appearance (nPNA), serum albumin, C-reactive protein (CRP), and lipid profile. All measurements except BIA were performed on the seventh day and at 6 and 12 months after the start of PD.

RESULTS

60 patients (30 men; mean age 55.0 ± 12.5 years) were enrolled. Increase in body weight continued during the 12 months but visceral and subcutaneous fat mass increased during the first 6 months and decreased during the second 6 months. While hematocrit and serum albumin decreased during the first 6 months, they did not change during the second 6 months. Serum creatinine, total cholesterol, and triglyceride increased similarly to the weight pattern. While nPNA decreased during the 12 months, Kt/V, SGA, and CRP did not change. Patients that had more visceral fat mass at the start of PD had less gain of visceral fat mass during the first 6 months (r = -0.821, p = 0.002). Patients that had more subcutaneous fat mass at the start of PD had less gain of subcutaneous fat mass (r = -0.709, p = 0.015). The change in weight was not associated with the change in visceral or subcutaneous fat during the first 6 months.

CONCLUSION

Patients starting PD experience weight gain, including visceral and subcutaneous fat, during the first 6 months of PD. Patients with high baseline fat mass had less increase in fat mass than those with low baseline fat mass, regardless of visceral or subcutaneous fat mass.

Peritoneal adipocytes and their role in inflammation during peritoneal dialysis

Adipose tissue is a major site of chronic inflammation associated with peritoneal dialysis (PD) frequently complicating peritonitis. Adiposity-associated inflammation plays a significant contributory role in the development of chronic inflammation in patients undergoing maintenance PD. However, the molecular and cellular mechanisms of this link remain uncertain. Adipose tissue synthesizes different adipokines and cytokines that orchestrate and regulate inflammation, insulin action, and glucose metabolism locally and systemically. In return, inflammation retards adipocyte differentiation and further exacerbates adipose dysfunction and inflammation. An understanding of the inflammatory roles played by adipose tissue during PD and the healing mechanism of injured mesothelium will help to devise new therapeutic approach to slow the progression of peritoneal damage during peritoneal dialysis. This article reviews the roles of peritoneal adipose tissue in chronic peritoneal inflammation under PD and in serosal repair during PD.

Determinants of plasma adiponectin levels in nondiabetic subjects with moderate to severe chronic kidney disease

OBJECTIVE

Our objective was to determine factors associated with adiponectin levels in subjects with stage III to IV chronic kidney disease (CKD).

DESIGN

We used a cross-sectional analysis.

SETTING

All kidney-disease subjects and controls were recruited at Vanderbilt University Medical Center (Nashville, TN) and Maine Medical Center (Portland, ME).

PATIENTS

We recruited 95 stage III to IV CKD subjects. Kidney-disease subjects with history of diabetes mellitus were excluded from the study.

INTERVENTIONS

There were no interventions.

RESULTS

Subjects with stage IV CKD had significantly higher adiponectin levels compared with those with stage III CKD (30.6 +/- 22.8 microg/mL vs. 21.1 +/- 14.6 microg/mL mean +/- SD, P = .05). Adiponectin was significantly correlated with gender (P = .01), high-density lipoproteins (P < .001), triglycerides (P = .004), and weight (P = .04) upon unadjusted analysis. Using multiple linear regression analysis, gender (P = .03), high-density lipoproteins (P = .001), triglycerides (P = .04), and high-sensitivity C-reactive protein (P = .004) were independently associated with adiponectin.

CONCLUSIONS

Gender, high-density lipoproteins, triglycerides, and high-sensitivity C-reactive protein are major determinants of adiponectin levels in nondiabetic stage III to IV CKD. Insulin resistance, body mass index, and body fat percentage were not associated with adiponectin levels. Plasma adiponectin levels are difficult to interpret in the setting of CKD because of multiple confounders that may influence the relationship between adiponectin, adiposity, and insulin resistance.

Skin Color is Associated with Insulin Resistance in Nondiabetic Peritoneal Dialysis Patients

Background

Changes in skin color are common among dialysis patients. They are associated with urochrome pigments, hemoglobin, and changes in cutaneous vasculature. Insulin resistance (IR) is strongly linked to cutaneous vascular dysfunction and is prevalent in dialysis patients. We postulated skin color may be associated with IR in dialysis patients because of the alternation in cutaneous vasculature.

Methods

50 nondiabetic peritoneal dialysis (PD) patients were recruited for measurements of skin color by the Commission Internationale de I'Eclairage (CIE; International Commission on Illumination) system (“L” “a” “b” system). The “L” values represent skin brightness, “a” redness, and “b” yellowness. Correlation analysis between skin color, homeostatic model assessment (HOMAIR), high-density lipoprotein cholesterol (HDL-C), and adiponectin was performed.

Results

We divided patients (age 45 ± 13 years, 31 women) into 3 groups according to tertiles of HOMAIR. Patients with higher HOMAIR had a trend to have poor skin color (lower “a” and “b” values; p = 0.038 and 0.064). HOMAIR, adiponectin, and HDL-C levels were correlated with “a” and “b” values in logarithm (all p < 0.05). After adjustments for age, hemoglobin level, duration of PD, and residual renal glomerular filtration rate, only HOMAIR was associated with “a” values ( p = 0.038) and HDL-C was associated with “b” values ( p = 0.048) in logarithm.

Conclusions

Skin color, measured noninvasively, is associated with HOMAIR and HDL-C. Nondiabetic PD patients that had more severe IR had worse skin color.

Serum levels of the adipokine FGF21 depend on renal function

OBJECTIVE

To investigate renal elimination of the adipokine fibroblast growth factor 21 (FGF21) by determining circulating FGF21 levels in patients on chronic hemodialysis (CD) as compared with control subjects with a glomerular filtration rate (GFR) >50 ml/min.

RESEARCH DESIGN AND METHODS

FGF21 was determined by enzyme-linked immunosorbent assay in control (n = 60) and CD (n = 60) patients and correlated to clinical and biochemical measures of renal function, glucose and lipid metabolism, and inflammation in both groups.

RESULTS

Median serum FGF21 levels were >15-fold higher in CD patients (3,710.6 ng/l) than in subjects with a GFR >50 ml/min (201.9 ng/l) (P < 0.001). Furthermore, serum creatinine positively and GFR negatively predicted FGF21 concentrations in multiple regression analyses in control subjects (P < 0.05).

CONCLUSIONS

FGF21 serum levels increase in CD patients and are related to markers of renal function in control subjects.

Adipokines influencing metabolic and cardiovascular disease are differentially regulated in maintenance hemodialysis

Adipokines including leptin, adiponectin, visfatin, resistin, and interleukin (IL)-6 significantly influence energy metabolism, insulin sensitivity, and cardiovascular health. In the current study, we investigated serum levels of these adipokines in diabetic and nondiabetic patients on maintenance hemodialysis (MD) as compared with controls with a glomerular filtration rate greater than 50 mL/min. Serum leptin, adiponectin, high-molecular-weight (HMW) adiponectin, visfatin, resistin, and IL-6 were determined by enzyme-linked immunosorbent assay in control (n = 60) and MD (n = 60) patients and correlated to clinical and biochemical measures of renal function, glucose, and lipid metabolism, as well as inflammation. Adiponectin, visfatin, resistin, and IL-6 were significantly elevated in MD patients as compared with controls. In multivariate analyses, sex and body mass index were independently correlated with serum leptin levels in both controls and MD patients. Furthermore, insulin resistance was independently and negatively associated with adiponectin and HMW adiponectin in both groups. Moreover, circulating resistin levels were independently correlated with serum visfatin concentrations in control and MD patients. However, various independent associations were only found in either controls or patients on MD. Thus, serum IL-6 levels were strongly and independently associated with C reactive protein and resistin in MD patients but not control subjects. We show that levels of various adipokines are significantly increased in MD patients. Furthermore, regulation of adipokines in vivo strongly depends on renal function. Regulation of HMW adiponectin is similar as compared with total adiponectin in the patients studied.

Adipocytokines leptin and adiponectin, and measures of malnutrition-inflammation in chronic renal failure: is there a relationship?

BACKGROUND

Serum levels of adipocytokines such as leptin and adiponectin are significantly elevated in patients with chronic renal failure (CRF). The effect of such adipocytokines on malnutrition in the CRF population has been of substantial interest. We sought to determine the relationship between plasma leptin and adiponectin levels and malnutrition-inflammation status in end-stage renal disease patients.

METHODS

Thirty patients (15 women and 15 men; mean [+/-SD] age, 50 +/- 14 years) on hemodialysis, and 30 patients (12 women and 18 men; mean [+/-SD] age, 47 +/- 16) on continuous ambulatory peritoneal dialysis, were enrolled in this study. Adipocytokine levels were measured by enzyme-linked immunosorbent assay. Inflammatory markers, such as high-sensitivity serum C-reactive protein (hs-CRP), ferritin, and a nutritional inflammatory scoring system known as the malnutrition-inflammation score (MIS), were also measured in all patients.

RESULTS

Serum leptin had negative correlations with ferritin (r = -0.33, P = .016) and MIS (r = -0.39, P = .003). Adiponectin had a weak positive correlation with MIS (r = 0.26, P = .050), indicating that an increased level of serum adiponectin was associated with a worse nutritional status. Levels of hs-CRP, serum albumin, cholesterol, and triglycerides did not correlate with nutritional status.

CONCLUSIONS

Serum leptin concentration seems to be a marker of good nutritional status, rather than an appetite-suppressing uremic toxin, in patients with CRF. However, the positive correlation between serum adiponectin and worse nutritional-inflammatory status suggests that elevated adiponectin levels may contribute to the pathogenesis of malnutrition in such patients.