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

Circulating and Adipose Tissue Adiponectin Level and Outcomes in Incident Peritoneal Dialysis Patients

Rationale & Objective

Cardiovascular disease is the major cause of mortality and morbidity in peritoneal dialysis (PD) patients. Adiponectin, a key adipokine, is related to obesity and insulin resistance. We determined the clinical and prognostic value of plasma adiponectin level and its adipose tissue messenger RNA (mRNA) expression in new PD patients.

Study Design

Retrospective analysis of a prospective observational study.

Setting & Participants

152 new PD patients from a single center; 6 adults undergoing abdominal surgeries without kidney disease served as controls.

Predictors

Plasma adiponectin level and its adipose tissue mRNA expression.

Outcomes

Body build and composition, patient and technique survival.

Analytical Approach

Adiponectin level and mRNA expression were grouped in quartiles for correlation analysis for body build and Cox regression for survival analysis.

Results

The median plasma adiponectin level was 31.98 μg/mL (IQR, 16.81-49.49 μg/mL), and adiponectin mRNA expression in adipose tissue was 1.65 times higher than in controls (IQR, 0.98-2.63). There was a modest but statistically significant correlation between plasma adiponectin and its adipose tissue mRNA expression (r = 0.40, P < 0.001). Plasma adiponectin level inversely correlated with body mass index, waist-hip ratio, mid-arm circumference, adipose tissue mass, plasma triglyceride (r = -0.39, -0.38, -0.41, -0.38, and -0.30, respectively; P < 0.001 for all), as well as serum insulin level (r = -0.24, P = 0.005). Similar correlations were present but less marked with adipose tissue adiponectin mRNA level. Neither plasma adiponectin level nor adipose tissue adiponectin mRNA level predicted patient or technique survival.

Limitations

Observational study, single center, single baseline measurement.

Conclusions

Plasma adiponectin level correlated with the degree of adiposity in new PD patients. However, neither plasma adiponectin level nor its adipose tissue mRNA expression was an independent prognostic indicator in kidney failure patients newly started on PD.

Association of adipocytokines with peritoneal function

BACKGROUND

Preservation of peritoneal function is crucial for the continuation of peritoneal dialysis (PD). A previous study suggested that blood cholesterol is involved in the preservation of peritoneal function; therefore, we determined whether adipocytokines can predict peritoneal function preservation.

METHODS

Eighty patients were enrolled. Serum adiponectin, leptin, apelin, various blood components, and estimated glomerular filtration rate (eGFR) (mL/min/m²) were measured. In addition, the duration of PD, presence or absence of peritonitis and diabetes mellitus, body mass index, urine output, peritoneal K_t/V, renal K_t/V, weekly K_t/V, peritoneal creatinine clearance rate (CCr), renal CCr, weekly CCr, use or nonuse of statin products, dialysate volume, glucose exposure, and use or nonuse of icodextrin dialysate were assessed. Peritoneal equilibration tests were performed at 6-month intervals, and dialysate-to-plasma [D/P] ratio and glucose uptake ratio [D/D₀] were measured. Associations of the baseline values and their percent changes with various adipocytokines and test items were evaluated.

RESULTS

Multiple regression analyses identified adiponectin (p = 0.0392, p = 0.0348) as a significant predictive factor of D/P and D/D₀ ratios. eGFR was identified as a significant predictive factor (p = 0.015) of percent change in the D/P ratio. Apelin (p = 0.0484), high-density lipoprotein cholesterol (p = 0.0066), dialysate volume (p = 0.0223), and urine output (p = 0.0020) were identified as factors affecting the duration of PD.

CONCLUSIONS

Adipocytokines are a predictive factor of peritoneal function and the duration of PD in patients undergoing PD.

Development of DNA aptamer-based sensor for electrochemical detection of C-reactive protein

C-reactive protein (CRP) is a crucial biomarker of cardiovascular diseases and for its detection both optical and electrochemical techniques were applied. This study concerns the application of DNA aptamer as recognition layer for CRP detection. For that purpose aptamer immobilization method on gold surface was selected and the content of receptor layer was optimized to ensure an efficient binding to target protein. The quality of the monolayer was verified by the application of chronocoulometry and atomic force microscopy. Using thiolated aptamers provided the formation of layers of highest density and stability. The square-wave voltammetry experiments performed in the presence of methylene blue redox indicator revealed a linear response of aptasensor towards CRP in the range from 1 to 100 pM. Moreover, a DNA aptamer - based sensor showed good selectivity towards C-reactive protein in comparison to interfering proteins including BSA and IgE. Finally, the analysis of CRP in serum sample was conducted using the developed aptasensor.

Waist circumference as a predictor of mortality in peritoneal dialysis patients: a follow-up study of 48 months

Body-fat gain is a common finding among peritoneal dialysis (PD) patients, and the accumulation of adipose tissue occurs predominantly in the abdominal area. Waist circumference (WC) is a reliable marker of abdominal obesity and its association with worse outcomes has been demonstrated in non-dialysis and haemodialysis patients. We aimed at investigating whether WC measurements as well as the changes over time in WC were able to predict mortality in PD patients. This prospective study included 109 patients undergoing PD (57 % male, age 52 (sd 16) years, 32 % diabetics, 48 % BMI≥25 kg/m2). WC was measured at the umbilicus level (empty abdominal cavity), and values >88 cm for women and >102 cm for men were considered high. Nutritional status and laboratory parameters were also evaluated. WC was measured at baseline and after 6 months, and mortality was registered during a period of 48 months. High WC was observed in 55 % of women and in 23 % of men at baseline. After 6 months, 61 % of the patients showed an increased WC. At the end of the study, twenty-seven deaths were registered. A significant increase in WC was observed only in the non-survivor group. In the Cox regression analysis adjusting for sex, age, duration on dialysis, diabetes, BMI, serum albumin and C-reactive protein, high WC at baseline as well as the 6-month increase in WC were independently associated with mortality. This study demonstrated that a high WC and the increase over time in WC were both predictors of mortality in PD patients.

[The specific nutritionnal care in peritoneal dialysis]

Protein energy wasting is a major complication in peritoneal dialysis. It is leading to a poor quality of life and increasing mortality. Diagnosis must be early, according to criteria defined by the International society of renal nutrition and metabolism. It is necessary to appropriate the diagnostic tools with dialysis method. The nutritional care is difficult in peritoneal dialysis. Indeed, studies are limited and practical nutrition is complex. In this point of view, we propose to treat guidelines for protein energy wasting, in peritoneal dialysis patients.

Body composition in chronic kidney disease

PURPOSE OF REVIEW

To summarize the latest information on body composition among patients with chronic kidney disease and its association with outcomes.

RECENT FINDINGS

Obesity is increasing among patients with end-stage renal disease and is more prevalent when direct measures of adiposity are used rather than BMI. High BMI is not associated with better survival among patients with earlier chronic kidney disease or after kidney transplantation, suggesting that excess fat is most protective among the sickest patients. Despite the positive association between BMI and survival among patients with end-stage renal disease, visceral fat is associated with coronary artery calcification and adverse cardiovascular events. Muscle wasting is prominent among patients with chronic kidney disease, sometimes even in the setting of obesity. Obesity and muscle wasting are associated with worse physical functioning. Indicators of low muscle size and strength are associated with higher mortality. Some interventions can affect body composition, but whether they affect survival has not been determined.

SUMMARY

Recent studies show that a high BMI is not protective for all patients with chronic kidney disease and is associated with poor physical functioning and frailty. Visceral adiposity is associated with adverse cardiovascular outcomes. Sarcopenia is common among patients with end-stage renal disease and is associated with worse physical performance and higher mortality.

Associations of serum adiponectin with markers of cardio-metabolic disease risk in Indigenous Australian adults with good health, diabetes and chronic kidney disease

The higher serum adiponectin concentrations observed in females are often attributed to differences in adiposity or sex hormones. There is little data describing adiponectin in Indigenous Australians, and no studies examining its association with cardio-metabolic disease risk markers and chronic kidney disease (CKD).

AIM

To describe the relationship of serum adiponectin with cardio-metabolic disease risk markers and kidney function in a community-based sample of Indigenous Australian adults, with particular reference to sex-specific differences.

METHODS

A cross-sectional analysis of a community-based volunteer sample of 548 Indigenous Australian adults (62% female), stratified into five cardio-metabolic risk groups ranging from good health (strata-1) to high cardio-metabolic risk and low measured glomerular filtration rate (mGFR, <60ml/min/1.73m²) (strata-5). We examined serum adiponectin concentrations with cardio-metabolic risk markers, albuminuria and mGFR.

RESULTS

Indigenous Australian females had a lower than expected adiponectin concentration (3.5μg/ml), which was higher than males in strata 1-4 (as in other populations), but not in strata-5 (mGFR<60, p=0.19), and higher leptin: adiponectin ratio than other populations (7.8ng/μg - strata-1, healthy females; 12.2ng/μg - strata-3, females with diabetes and mGFR≥90). Female-gender, HDL-cholesterol (positive), mGFR and waist: hip ratio (WHR) (inverse) were independently associated with log-adiponectin when mGFR≥60; when mGFR<60, female-gender was associated with 0.27 units lower log-adiponectin.

CONCLUSION

Female-gender was not associated with higher adiponectin concentrations in Indigenous Australians with mGFR<60ml/min/1.73m². High WHR was frequent in both genders, and inversely associated with adiponectin. Longitudinal studies are needed to examine relationships of serum adiponectin, obesity and cardiovascular disease events in Indigenous Australians.