Temporal relation between body mass index and renal function in individuals with hypertension and excess body weight

High Perirenal Fat Volume Affect Negatively Renal Function in Living Renal Transplantation

OBJECTIVE

We aimed to investigate the effect of perirenal fat volume (PFV) on graft functions by calculating the PFV of donor kidney with routine computed tomography before renal transplantation.

METHODS

From May 2019 to December 2020, a total of 54 living donors and recipients who met the criteria for kidney donor were included in the study. Left donor nephrectomy was performed to all donors. Data of age, sex, body mass index (BMI), PFV of the donors, estimated glomerular filtration rate (eGFR), and serum creatinine measurement data of the recipients were recorded. Serum creatinine and eGFR of the recipients were recorded at the 12th month controls. The patients were sorted into 2 groups (G) according to their GFR values. G1, GFR <60 mL/min/1.73 m²; G2, GFR ≥ 60 mL/min/1.73 m².

RESULTS

There was no difference in terms of recipient sex, recipient age, donor sex, recipient BMI, and donor BMI between the 2 groups. The mean of PFV was higher in G1 and was statistically significant (P= 0.01). The ability of the donor BMI and PFV to predict G2 was evaluated by receiver operating characteristic curve analysis. It was determined that PFV predicted G2 to be statistically significant. In the multivariate logistic regression analysis, PFV (odds ratio = 0.988, 95% GA = 0.977-0.999, P = 0.03) was found as an independent predictor of G2.

CONCLUSIONS

In conclusion, our study showed PFV as an independent risk factor for low eGFR, revealing that the previously documented relevance of increased BMI with a low eGFR can be partially explained by PFV.

Silencing of RSPO1 mitigates obesity-related renal fibrosis in mice by deactivating Wnt/β-catenin pathway

Obesity, a global epidemic, is one of the critical causes of chronic kidney disease (CKD). R-spondin1 (RSPO1) possessing the potential to activate Wnt/β-catenin pathway was reported to be elevated in circulation of obesity objects. However, the function of RSPO1 and the latent mechanism in obesity-related CKD are still left to be revealed. In the present study, renal RSPO1 expression was increased in mice fed on high-fat diet (HFD) for 12 weeks. Lentivirus-mediated RSPO1 knockdown partly recovered obesity-related metabolic symptoms, while distinctly remitted kidney dysfunction and renal fibrosis in obesity mice. In vitro, recombinant RSPO1 was found to elevate leucine-rich repeat-containing G protein coupled receptor 4 (LGR4) expression, promote Wnt/β-catenin signaling pathway activation, facilitate epithelial-mesenchymal transition (EMT) and increase collagen deposition in HK2 renal tubular cells. Such pro-fibrotic effect of RSPO1 was diminished by LGR4 siRNA in HK2 cells. In summary, we demonstrate that RSPO1/LGR4 axis is involved in obesity-related renal fibrosis at least through activating Wnt/β-catenin signaling pathway, providing a potential therapeutic target for this disease.

Obesity measures at baseline, their trajectories over time, and the incidence of chronic kidney disease: A 14 year cohort study among Korean adults

BACKGROUND AND AIMS

We investigated the association of baseline obesity measures, i.e. body mass index (BMI), waist circumference (WC), hip circumference (HC), and waist-hip ratio (WHR), and their trajectories over time with incident chronic kidney disease (CKD).

METHODS AND RESULTS

Utilizing data from 2001 to 2014 for 9796 Korean adults without CKD at baseline, the association of baseline obesity measures with incident CKD was evaluated using logistic regression. Further, among 5605 subjects with repeated measures, the effect of the trajectories in obesity measures on CKD incidence was investigated via Cox regression. Baseline obesity in terms of BMI, WC, and HC increased the odds of incident CKD (odds ratio (OR) 1.19, 95% confidence interval (CI) 1.05-1.33; OR 1.22, 95% CI 1.07-1.38; and OR 1.25, 95% CI 1.11-1.41, respectively), while baseline WHR did not show such an association. A "became non-obese" BMI, WC, or WHR trajectory, and a "constantly not large" HC trajectory decreased the hazard of incident CKD (hazard ratio (HR) 0.70, 95% CI 0.50-0.99; HR 0.61, 95% CI 0.40-0.92; HR 0.55, 95% CI 0.35-0.85; and HR 0.81, 95% CI 0.69-0.95, respectively) when compared with a "constantly obese or became obese" trajectory.

CONCLUSION

Both baseline obesity and obesity trajectories over time were associated with CKD incidence. BMI and WC were equally good measures of CKD risk, while WHR was not. Separately examining WC and HC components of WHR (= WC/HC) may explain WHR's inconsistency, and WHR's usefulness as a measure of CKD risk should be reevaluated.

Association between obesity and risk of chronic kidney disease: A nationwide Cohort study in Taiwan

BACKGROUND AND AIMS

Increased body fat relates to enhanced inflammatory cytokine production, which, in turn, activates the renin-angiotensin-aldosterone system and increases the risk of chronic kidney disease (CKD). Herein, we aimed to examine the association between obesity and the risk of CKD in a population-representative cohort in Taiwan.

METHODS AND RESULTS

A multistage systematic sampling process was applied in the National Health Interview Survey (NHIS) 2000, 2005, and 2009. Participants were interviewed by a standardized face-to-face questionnaire to obtain information on their demographics, socioeconomic status, lifestyle factors, and body mass index (BMI). The BMI values were classified as follows: underweight (<18.5 kg/m²), normal (18.5-23.9 kg/m²), overweight (24-26.9 kg/m²), and obesity (≥27 kg/m²). The NHIS dataset was linked to National Health Insurance claims data to identify the incidence of CKD. Univariate and multivariate Cox proportional hazard models with competing risks were used to investigate the association between BMI and CKD incidence. We analyzed 45,012 subjects (mean age, 42.03 years; 50.09% males). During 374,254 person-years of follow-up, a total of 1913 new-onset CKD cases were identified. Kaplan-Meier curves comparing the four BMI groups revealed a significant difference (p < 0.01, log-rank test). After controlling for confounding factors, the relative risk of incident CKD was significantly higher in the obese group compared to the normal-weight group (adjusted hazard ratio = 1.32; 95% confidence interval: 1.17-1.49), with a significant linear trend (p < 0.01).

CONCLUSION

Obesity was suggested as an independent risk factor for CKD. Further studies focusing on the effect of losing weight on CKD prevention are warranted.

Scope and mechanisms of obesity-related renal disease

PURPOSE OF REVIEW

Obesity is established as an important contributor of increased diabetes mellitus, hypertension, and cardiovascular disease, all of which can promote chronic kidney disease (CKD). Recently, there is a growing appreciation that, even in the absence of these risks, obesity itself significantly increases CKD and accelerates its progression.

RECENT FINDINGS

Experimental and clinical studies reveal that adipose tissue, especially visceral fat, elaborates bioactive substances that contribute to the pathophysiologic renal hemodynamic and structural changes leading to obesity-related nephropathy. Adipocytes contain all the components of the renin-angiotensin-aldosterone system, plasminogen activator inhibitor, as well as adipocyte-specific metabolites such as free fatty acids, leptin, and adiponectin, which affect renal function and structure. In addition, fat is infiltrated by macrophages that can alter their phenotype and foster a proinflammatory milieu, which advances pathophysiologic changes in the kidney associated with obesity.

SUMMARY

Obesity is an independent risk factor for development and progression of renal damage. Although the current therapies aimed at slowing progressive renal damage include reduction in weight and rely on inhibition of the renin-angiotensin system, the approach will likely be supplemented by interventions aimed at obesity-specific targets including adipocyte-driven cytokines and inflammatory factors.

Para- and perirenal fat thickness is an independent predictor of chronic kidney disease, increased renal resistance index and hyperuricaemia in type-2 diabetic patients

BACKGROUND

Many interfering factors may reduce the reliability of waist circumference (WC) measurement in estimating the risk for chronic kidney disease (CKD) associated with obesity. Therefore, we determined the independent associations of para- and perirenal ultrasonographic fat thickness with the main markers of kidney function.

METHODS

A cross-sectional study was performed in 151 type-2 diabetic subjects. Para- and perirenal fat thickness was measured from the inner side of the abdominal musculature to the surface of the kidneys. CKD was defined as eGFR < 60 mL min(-1)1.73 m(-2).

RESULTS

Using both univariate and multivariate regression analyses, eGFR, renal resistance index and uricaemia were best predicted by para- and perirenal fat thickness even when BMI and waist circumference were further added in the statistical model (r(2): 0.366, P = 0.001; r(2): 0.529, P = 0.005; r(2): 0.310, P = 0.026, respectively), whereas waist circumference and BMI did not contribute independently of para- and perirenal fat thickness. Albuminuria was predicted by waist circumference but not by para- and perirenal fat thickness. In subjects with waist circumference above the diagnostic values of metabolic syndrome (48M/59F), eGFR significantly and progressively declined across tertiles of para- and perirenal fat thickness (87.0 ± 27.9 vs 83.5 ± 26.0 vs 62.3 ± 30.6 mL min(-1) 1.73 m(-2), adjusted P < 0.0001) despite comparable waist circumference, and an increasing frequency of CKD was observed across tertiles of subjects with waist circumference both below and above the metabolic syndrome diagnostic values (P < 0.05).

CONCLUSIONS

Para- and perirenal fat thickness is an independent predictor of kidney dysfunction in type-2 diabetes explaining an important proportion of the variance of eGFR, renal resistance index and uricaemia.