Association of metabolic syndrome in nondiabetic patients with increased risk for chronic kidney disease: the fat lady sings

Sex-specific effects of LiCl treatment on preservation of renal function and extended life-span in murine models of SLE: perspective on insights into the potential basis for survivorship in NZB/W female mice

Considerable research effort has been invested in attempting to understand immune dysregulation leading to autoimmunity and target organ damage. In systemic lupus erythematosus (SLE), patients can develop a systemic disease with a number of organs involved. One of the major target organs is the kidney, but patients vary in the progression of the end-organ targeting of this organ. Some patients develop glomerulonephritis only, while others develop rapidly progressive end organ failure. In murine models of SLE, renal involvement can also occur. Studies performed over the past several years have indicated that treatment with LiCl of females, but not males of the NZB/W model, at an early age during the onset of disease, can prevent development of end-stage renal disease in a significant percentage of the animals. While on Li treatment, up to 80 % of the females can exhibit long-term survival with evidence of mild glomerulonephritis which does not progress to renal failure in spite of on-going autoimmunity. Stopping the treatment led to a reactivation of the disease and renal failure. Li treatment of other murine models of SLE was less effective and decreased survivorship in male BxSB mice, exhibited little effect on male MRL-lpr mice, and only modestly improved survivorship in female MRL-lpr mice. This perspective piece discusses the findings of several related studies which support the concept that protecting target organs such as the kidney, even in the face of continued immune insults and some inflammation, can lead to prolonged survival with retention of organ function. Some possible mechanisms for the effectiveness of Li treatment in this context are also discussed. However, the detailed mechanistic basis for the sex-specific effects of LiCl treatment particularly in the NZB/W model remains to be elucidated. Elucidating such details may provide important clues for development of effective treatment for patients with SLE, ~90 % of which are females.

Socioeconomic status and reduced kidney function in the Whitehall II Study: role of obesity and metabolic syndrome

Background

Previous US-based studies have found that chronic kidney disease (CKD) disproportionately affects those of more adverse social circumstances. Our aim was to show the association between socioeconomic status (SES) and decreased kidney function in a European context and explore the role of obesity and metabolic syndrome. We consider the potential confounding effect of lean muscle mass.

Study Design

Cross-sectional.

Setting & Participants

White participants in the follow-up of the Whitehall II cohort: UK-based European population (age, 55-79 years; n = 5,533), of whom 4,066 men (73%) and 1,467 women (27%) with complete data were analyzed.

Predictors

Self-reported occupational grade/salary range.

Outcomes

Estimated glomerular filtration rate (GFR) using the CKD-EPI (CKD Epidemiology Collaboration) equation.

Measurements

Body mass index (BMI), serum lipid levels, blood pressure, Tanita TBF-300 body composition analyzer, impedance-derived lean mass index (LMI).

Results

Participants in a lower compared with higher occupational grade were at increased odds of having decreased GFR (age- and sex-adjusted OR, 1.31; 95% CI, 1.12-1.53; P = 0.001). Socioeconomic disparity in LMI was evident in women, but not men. After further adjustment for BMI and components of metabolic syndrome, the odds of decreased GFR in whites with a lower compared with higher occupational grade was attenuated by 23.3% (OR, 1.23; 95% CI, 1.06-1.45; P = 0.008). Adjustment for LMI explained 15% of the association between SES and estimated GFR.

Limitations

Cross-sectional design, missing data for subset of participants, no urinary data.

Conclusions

BMI and components of metabolic syndrome may explain up to a quarter of the association between low SES and decreased GFR, suggesting potential modifiable factors.

Obesity and metabolic syndrome-related chronic kidney disease in nondiabetic, nonhypertensive adults

Metabolic syndrome (MS) is associated with chronic kidney disease (CKD). The objective of this study is to examine the association between obesity and MS-related CKD in nondiabetic, nonhypertensive Korean adults. Korea National Health and Nutrition Examination Survey III data from 3771 nondiabetic, nonhypertensive Koreans were analyzed. Metabolic syndrome was defined according to the National Cholesterol Education Program-Adult Treatment Panel III, and CKD was diagnosed at an estimated glomerular filtration rate less than 60 mL/(min 1.73 m(2)). The crude and multivariate-adjusted odds ratios (ORs) of CKD associated with MS and its individual components were calculated using logistic regression models in a study population stratified by obesity. The prevalence of MS and CKD was 13.4% and 3.2%, respectively. The association between MS and CKD was significant in obese (OR, 2.91; 95% confidence interval [CI] = 1.34-6.34), but not nonobese (OR, 1.38; 95% CI = 0.60-3.17), subjects. In obese subjects, impaired fasting glucose (OR, 2.47; 95% CI = 1.10-5.57) and high triglyceride levels (OR, 2.42; 95% CI = 1.01-5.83) were risk factors for CKD, whereas no components were significantly associated with CKD in nonobese subjects. Our findings suggest that even in nondiabetic, nonhypertensive Korean adults, early detection and prevention of CKD in obese subjects with MS are critical.