Obesity, hypertension, and chronic kidney disease

Renal outcomes with sodium glucose cotransporter 2 (SGLT2) inhibitor, dapagliflozin, in obese insulin-resistant model

A growing body of evidence indicates that obesity and insulin resistance contribute to the progression of renal disease. This study was performed to determine the effects of dapagliflozin, a novel sodium glucose cotransporter 2 (SGLT2) inhibitor, on renal and renal organic anion transporter 3 (Oat3) functions in high-fat diet fed rats, a model of obese insulin-resistance. Twenty-four male Wistar rats were divided into two groups, and received either a normal diet (ND) (n = 6) or a high-fat diet (HFD) (n = 18) for 16 weeks. At week 17, the HFD-fed rats were subdivided into three subgroups (n = 6/subgroup) and received either a vehicle (HFD), dapagliflozin (HFDAP; 1.0 mg/kg/day) or metformin (HFMET; 30 mg/kg/day), by oral gavage for four weeks. Metabolic parameters, renal function, renal Oat3 function, renal oxidative stress, and renal morphology were determined. The results showed that obese insulin-resistant rats induced by HFD feeding had impaired renal function and renal Oat3 function together with increased renal oxidative injury. Dapagliflozin or metformin treatment decreased insulin resistance, hypercholesterolemia, creatinine clearance and renal oxidative stress leading to improved renal function. However, dapagliflozin treatment decreased blood pressure, serum creatinine, urinary microalbumin and increased glucose excretions, and showed a greater ability to ameliorate impaired renal insulin signaling and glomerular barrier damage than metformin. These data suggest that dapagliflozin had greater efficacy than metformin for attenuating renal dysfunction and improving renal Oat3 function, at least in part by reducing renal oxidative stress and modulating renal insulin signaling pathways, and hence ameliorating renal injury.

Diet Composition for the Management of Obesity and Obesity-related Disorders

Healthy nutrition is essential for prevention of disease and for maintenance or promotion of health; although healthy nutrition remains to be precisely defined. Over the past several decades, various types of nutrients have been functionally validated and considered as critical components of healthy nutrition, which commonly include fiber-enriched carbohydrates, mono- or poly-unsaturated fatty acids, essential amino acids, and certain micronutrients. When managing obesity and obesity-associated metabolic diseases, much attention has been paid to the content of nutrients that is considered as healthy nutrition. Accumulating evidence also suggests that nutrient composition could be more important than the content of individual nutrients in the context of reducing body weight and obesity-associated risk for metabolic diseases. Consistently, it would be more important to focus on diet with differences in nutrient ratios rather than individual type(s) of nutrients in terms of managing obesity and metabolic diseases. In this review, recent advances in dietary management of obesity and obesity-related metabolic diseases have been discussed. This review also has highlighted several specific diet compositions and their differences in managing hypertension, type 2 diabetes, and non-alcoholic fatty liver disease.

Metabolically Healthy or Metabolically Unhealthy Obese HIV-Infected Patients: Mostly a Matter of Age?

Background: Life expectancy of HIV-infected patients has increased with antiretroviral treatment (ART). Chronic diseases associated with aging, including metabolic and cardiovascular diseases are becoming more prevalent in this population. We aimed to evaluate the association of obesity and aging with cardiometabolic comorbidities and metabolic health status among patients with HIV infection. Methods: We evaluated 580 HIV-1 infected patients (71.7% male, mean age of 47.7 ± 11.5 years). We analyzed the association of age and obesity (defined by and by central obesity) with gender, duration of HIV infection, and ART, anthropometric parameters, cardiometabolic comorbidities, Framingham risk score (FRS), blood pressure, lipid profile, uric acid, liver biochemical tests, and glycemic profile. Furthermore, we analyzed the above-mentioned associations according to the category and central obesity into the metabolically healthy (MH) and unhealthy (MUH) categories. To evaluate the association of anthropometric parameters with cardiometabolic comorbidities, we performed unadjusted and adjusted logistic regression models. Results: The prevalence of excessive weight and cardiometabolic comorbidities increased with age. Patients with normal weight were younger and there was a higher proportion of female patients in the obesity group. The prevalence of hypertension and metabolic syndrome were higher among patients who were overweight or with obesity. The FRS was higher among patients with obesity. The proportion of MUH patients was higher among patients with excessive weight and central obesity. MUH patients had more cardiometabolic comorbidities and a higher FRS. In the normal weight group, MUH patients were older, and in the obesity group they were more likely to be male. The anthropometric parameter most associated with metabolic syndrome was waist circumference and that most associated with hypertension was waist-to-height ratio. The anthropometric parameter most associated with diabetes and FRS was waist-to-hip ratio. Conclusion: Patients with HIV present a high prevalence of obesity and related comorbidities. Ageing significantly contributes to metabolic dysfunction in this population. The proportion of MUH patients is higher among groups with excessive weight and central obesity, with those patients presenting a higher cardiovascular risk. Our results highlight the importance of evaluating and addressing obesity in patients with HIV, as well as metabolic comorbidities and cardiovascular risk.

Obesity as a Disease

Obesity is a complex disease with many causal factors, associated with multiple comorbidities that contribute to significant morbidity and mortality. It is a highly prevalent disease that poses an enormous health and economic burden to society. This article reviews the mechanisms of obesity and its related comorbidities.

Relevance of megalin receptor injury with nuclear factor-kappa B upregulation in acute kidney injury induced in rats

Proximal tubule protein take-up is interceded by 2 receptors, megalin and cubilin. These receptors rescue an assortment of filtered ligands including fundamental vitamins and hormones. The objective of this study was to investigate the potential relation of megalin receptor injury with nuclear factor-kappa B (NF-κB) upregulation in acute kidney injury rat model. Twenty four rats were allocated into two groups: control group received saline, while the second group was intoxicated with cadmium chloride (2.4 mg Cd/kg/day i.p) for 30 days. Blood urea nitrogen, serum creatinine, tissue oxidant-antioxidant parameters (malondialdehyde [MDA] and reduced glutathione [GSH]) and expression levels for NF-κB, toll like receptor-2 (TLR2), toll like receptor-4 (TLR4), and megalin receptor were estimated. Noticeable downregulation of megalin receptor versus upregulation of NF-κB, TLR2, and TLR4 were observed in AKI rat model together with significant elevation in MDA as well as significant reduction in GSH. The study concluded that the oxidative stress in kidney tissue leads to megalin receptor damage, which indeed motivates upregulation of NF-κB through TLRs 2 and 4 pathways.

Immunologic and endocrine functions of adipose tissue: implications for kidney disease

Excess adiposity can induce adverse sequelae in multiple cell types and organ systems. The transition from the lean to the obese state is characterized by fundamental cellular changes at the level of the adipocyte. These changes affect the local microenvironment within the respective adipose tissue but can also affect nonadipose systems. Adipocytes within fat pads respond to chronic nutrient excess through hyperplasia or hypertrophy, which can differentially affect interorgan crosstalk between various adipose depots and other organs. This crosstalk is dependent on the unique ability of the adipocyte to coordinate metabolic adjustments throughout the body and to integrate responses to maintain metabolic homeostasis. These actions occur through the release of free fatty acids and metabolites during times of energy need - a process that is altered in the obese state. In addition, adipocytes release a wide array of signalling molecules, such as sphingolipids, as well as inflammatory and hormonal factors (adipokines) that are critical for interorgan crosstalk. The interactions of adipose tissue with the kidney - referred to as the adipo-renal axis - are important for normal kidney function as well as the response of the kidney to injury. Here, we discuss the mechanistic basis of this interorgan crosstalk, which clearly has great therapeutic potential given the increasing rates of chronic kidney disease secondary to obesity and type 2 diabetes mellitus.

Metabolic syndrome components and estimated glomerular filtration rate based on creatinine and/or cystatin C in young adults: A gender issue?

AIMS

This work aims to identify correlations between estimated glomerular filtration rate (eGFR) based on creatinine and/or cystatin C (Cr, CysC) with metabolic syndrome (MS) components in young adults, according to gender.

MATERIAL AND METHODS

This is a cross sectional study, where young adults aged between 18 and 30 were matched by gender, age and body mass index. All subjects underwent clinical evaluation and blood sampling for laboratory measurements. MS was determined according to the JIS criteria. The eGFR was estimated using CKD-EPI equations (eGFR_Cr; eGFR_CysC; eGFR_Cr-CysC).

RESULTS

We evaluated 78 subjects with a mean age of 24.5 years. 10.2% had MS, with higher incidence among males (15.4% ♂ vs. 5.1% ♀). Elevated waist circumference was the MS component most observed. Significant correlations (Pearson; p<0.05) between eGFR and metabolic markers were observed only in males. In addition, we observed a significant association between the increase of MS components and the decay of eGFR_Cr and eGFR_Cr-CysC (zero vs. two or more components, ANOVA, p<0.05) only among males.

CONCLUSION

eGFR decay associated with components of MS and insulin resistance in young male adults could represent a worrying specific risk and indicate that further studies are needed to better understand these findings.

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.

Obesity, weight change, and chronic kidney disease in patients with type 2 diabetes mellitus: A longitudinal study in Taiwan

BACKGROUND

The aim of the present study was to investigate relationships between the risk of chronic kidney disease (CKD) and obesity and weight changes in Asian patients with type 2 diabetes.

METHODS

At baseline (2003-05), 1187 diabetic patients aged 30-70 years were recruited to the study, with follow-up surveys completed in 2008, 2009, and 2010. Chronic kidney disease was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min per 1.73 m² ; body mass index (BMI) was categorised as normal (18.5-22.9 kg/m² ), overweight (23-27.4 kg/m² ), or obese (≥27.5 kg/m² ); waist circumference (WC) ≥80 cm for women and ≥90 cm for men was taken to indicate abdominal obesity. Changes in weight and WC were calculated from baseline to each follow-up survey. Relative risk (RR) and 95% confidence intervals (CIs) of CKD were estimated. To estimate the risk for incident CKD, associations were examined in patients without CKD at baseline (n = 881).

RESULTS

Over 7 years of follow-up, obesity (RR 1.48; 95% CI 1.08-2.04; P = 0.015) and high WC (RR 1.23; 95% CI 1.00-1.52; P = 0.049) were associated with CKD after adjusting for covariates. Among participants without CKD at baseline, those who gained >10% weight (RR 1.43; 95% CI 1.07-1.90; P = 0.015) and in whom WC increased >15% (RR 1.37; 95% CI 1.01-1.85; P = 0.045) had a higher risk of incident CKD than those who remained stable (±5% changes in weight or WC).

CONCLUSIONS

Diabetic patients who are obese and those with excessive central fat were more likely to have CKD. Large weight gain (>10%) and increases in WC (>15%) independently predicted incident CKD.

A non-laboratory-based risk score for predicting diabetic kidney disease in Chinese patients with type 2 diabetes

Aim

To construct a simple screening tool for predicting diabetic kidney disease in Chinese patients with type 2 diabetes.

Materials and Methods

In the development cohort, the clinical and procedural characteristics of the 4,795 patients were considered as candidate univariate predictors of diabetic kidney disease. The β-coefficients derived from a multiple logistic regression model predicting the presence of DKD were used to calculate the risk score. The performance of the risk score was validated in a cross-sectional and a prospective cohort population.

Results

The risk score included sex, body mass index, systolic blood pressure, and duration of diabetes. The total point ranged from 0 to 39. In the development cohort, compared with participants with risk score < 10, those with risk score between 10 to 20, 21 to 30, and > 30 had ORs of 3.21, 7.92 and 17.55 for developing diabetic kidney disease, respectively. In the prospective cohort, 60.9% patients with risk score over 30 were expected to develop DKD at 72 months of follow-up.

Conclusions

Sex, body mass index, systolic blood pressure, and duration of diabetes were independent predictors of diabetic kidney disease, and the derived risk equation was a simple screening tool for screening diabetic kidney disease in Chinese patients with type 2 diabetes.

A Profile of Renal Function in Northern Cameroonians with Essential Hypertension

BACKGROUND/AIM

The two-way cause and effect relationship existing between high blood pressure and kidney dysfunction is currently a well-documented phenomenon with patients in either category being almost equally predisposed to the other pathology. Our goal was to assess the renal function capacity of hypertensive patients in our setting.

METHODS

This cross-sectional descriptive study involved the determination of blood pressure levels and the collection of blood and urine samples for the measurement of renal function markers. Hypertensive patients who came for medical follow-up constituted the study participants, and were enrolled consecutively into the study from February to May 2015. Data analysis was performed using the SPSS 20.0 software, and significant differences were determined at p < 0.05.

RESULTS

The prevalence of elevated creatinine and urea levels were 35 and 27%. Eighty percent of the participants had a decreased glomerular filtration rate (≤90 mL/min/1.73 m3), with at least 36% recording less than 60 mL/min/1.73 m3. Proteinuria and glucosuria were recorded in 15% and 8% of the participants, respectively. The mean diastolic pressure was observed to be significantly higher in participants with proteinuria (p = 0.016), and participants' weight directly correlated with systolic blood pressure (p = 0.015). Furthermore, the mean estimated glomerular filtration rate was relatively lower in participants >60 years compared to those <60 years (p < 0.001).

CONCLUSION

Renal function is often perturbed in hypertensive patients, and good blood pressure control may reduce the progression of renal impairment. Thus, a systematic evaluation of renal function in addition to blood pressure control in hypertensive patients is indispensable towards effectively reducing the occurrence of renal events and preventing end-stage renal disease.

Primary prevention of cardiovascular disease in older adults in China

Over the past two decades, the percentage of Chinese who is 60 years or older has increased from 5.2% in 1995 to 10.5% in 2015. Approximately 16% of the population in China was 60 years old and above in 2015. Since 1990, cardiovascular disease (CVD) has been the leading cause of death in China. Cardiovascular medications of older adults are usually more complicated than younger age groups due to polypharmacy, the presence of comorbidities and more susceptible to treatment-related adverse outcomes. Therefore, effective primary prevention of CVD for older adults is important in sustaining the health of older adults and reducing the burden of the healthcare system. Proper management of CVD-related risk factors, such as hypertension, dyslipidemia, diabetes and obesity, can remarkably reduce risks of CVDs in older Chinese. These risk factors can be modified by managing blood pressure, glucose and lipids via lifestyle modifications or receiving medications. Smoking cessation, healthy diets, strict alcohol intake and moderate physical exercise are examples of recommended lifestyle changes for remarkably recovering health conditions of older adults who have hypertension, dyslipidemia, obesity, diabetes or complications. Treatment prescriptions of older adults, in general, are recommended to be individualized and to be initiated at a low dose. The future directions for better primary CVD prevention in older adults include establishing guidelines for primary prevention of CVD for different older adults and further research on better management strategies of CVD risks for elderly Chinese.

Systematic review and meta-analysis of school-based obesity interventions in mainland China

Background

Numerous school-based interventions for childhood obesity have been emerging in mainland China in recent decades, but little is known about the effectiveness of such interventions. This study aims to assess the effectiveness of school-based interventions for childhood obesity conducted in mainland China.

Methods

A systematic search was undertaken in eight databases to identify both randomized and non-randomized controlled trials from January 1990 to December 2015 examining the effectiveness of school-based obesity interventions. A random effects meta-analysis was conducted assessing the impact of included interventions on (body mass index) BMI. The quality of each included studies were assessed using Effective Public Health Practice Project Quality Assessment Tool. A P value <0.05 (two-sided) was considered statistically significant.

Result

Of the seventy-six included studies, we found physical activity and health education were the two most common components of interventions. More treatment studies were effective compared with prevention studies (85.0% vs. 58.3%). Comprehensive interventions involving physical activity and health education appeared more effective than the physical activity only interventions in both obesity treatment and prevention studies. The meta-analyses showed comprehensive interventions involving physical activity and health education had larger effect on the change of BMI than physical activity only interventions (treatment studies: -1.80 kg/m² (95% CI: -2.15,-1.44) vs. -0.91 kg/m² (95% CI: -1.15,-0.67); prevention studies: -0.19 kg/m² (95% CI: -0.27, -0.11) vs. +0.05 kg/m² (95% CI: -0.04, +0.15)).

Conclusions

Comprehensive school-based interventions may assist in tackling the rising prevalence of childhood obesity in mainland China.

Association Between Body Mass Index Combined with Albumin: creatinine Ratio and All-cause Mortality in Chinese Population

The association between body mass index (BMI) combined with albumin: creatinine ratio (ACR) and all-cause mortality in the general population has not been established. To address this, we examined a representative sample from the general population of China. The study included 46,854 participants with a follow-up of 4.6 years. Compared to the normal weight with ACR <10 mg/g group (the reference group), the crude hazard ratios (HRs) for all-cause mortality for the underweight with ACR >10 mg/g, normal weight with ACR >10 mg/g, overweight with ACR >10 mg/g, and obese with ACR >10 mg/g groups, were 2.22 (95% CI, 1.41 to 3.49), 1.70 (95% CI, 1.42 to 2.04), 1.52 (95% CI, 1.22 to 1.89), and 2.05 (95% CI, 1.45 to 2.89), respectively. After multivariable adjustments for age, race, comorbidities, and baseline eGFR, the HRs for the underweight with ACR >10 mg/g and normal weight with ACR >10 mg/g groups were 1.85 (95% CI, 1.17 to 2.91) and 1.36 (95% CI, 1.13 to 1.63), respectively. The results indicate that BMI combined with ACR can better predict all-cause mortality than BMI alone in the general Chinese population. Underweight and normal weight people with elevated ACR are at a higher risk of all-cause mortality than those in the same BMI category with ACR <10 mg/g.

High-fat diet increases pain behaviors in rats with or without obesity

Obesity is associated with increased risk for chronic pain. Basic mechanisms for this association are poorly understood. Using a milder version of a radicular pain model, local inflammation of the dorsal root ganglion (DRG), we observed marked increases in mechanical and cold allodynia in rats of both sexes that were maintained on a high-fat diet (HFD) for 6 weeks prior to DRG inflammation. Notably, this increase in pain-related behaviors occurred in both Long-Evans and Sprague-Dawley rats despite the fact that the 6-week HFD exposure induced obesity (e.g., increased insulin, leptin, weight, and percent body fat) in the Long-Evans, but not Sprague-Dawley, strains. This suggested that HFD, rather than obesity per se, increased pain behaviors. Increased pain behaviors were observed even after a much shorter (1 week) exposure to the HFD but the effect was smaller. HFD also increased behavioral responses and paw swelling to paw injection of complete Freund’s adjuvant, a model of peripheral inflammatory pain. No change was detected in plasma cytokine levels in HFD rats. However, increased macrophage infiltration of the DRG was observed in response to the HFD, absent any pain model. The results suggest that HFD can increase pain even when it does not cause obesity.

Renal Afferents

Purpose of Review

The etiology of hypertension, a critical public health issue affecting one in three US adults, involves the integration of the actions of multiple organ systems, including the renal sympathetic nerves. The renal sympathetic nerves, which are comprised of both afferent (sensory input) and efferent (sympathetic outflow) arms, have emerged as a major potential therapeutic target to treat hypertension and disease states exhibiting excess renal sympathetic activity.

Recent Findings

This review highlights recent advances in both clinical and basic science that have provided new insight into the distribution, function, and reinnervation of the renal sympathetic nerves, with a focus on the renal afferent nerves, in hypertension and hypertension-evoked disease states including salt-sensitive hypertension, obesity-induced hypertension, and chronic kidney disease.

Summary

Increased understanding of the differential role of the renal afferent versus efferent nerves in the pathophysiology of hypertension has the potential to identify novel targets and refine therapeutic interventions designed to treat hypertension.

Association Between Obesity and Chronic Kidney Disease, Defined by Both Glomerular Filtration Rate and Albuminuria, in Korean Adults

BACKGROUND

Chronic kidney disease (CKD) has often been defined based on glomerular filtration rate (GFR) alone. The Kidney Disease: Improving Global Outcomes guideline highlights albuminuria in the CKD definition. Thus, we investigated the association between obesity and CKD, as defined by both GFR and albuminuria, in Korean adults.

METHODS

We used Korea National Health and Nutrition Examination Survey 2011-2014 data (N = 19,331, ≥19 years old) representing the national Korean population. CKD was classified by (1) estimated GFR (eGFR) < 60 mL/min/1.73 m² (CKD_GFR); (2) albumin-to-creatinine ratio (ACR) ≥30 mg/gram (CKD_ACR); and (3) eGFR < 60 mL/min/1.73 m² or ACR ≥30 mg/gram (CKD_Risk). Associations between obesity and each CKD category were evaluated using multivariate logistic regression analysis.

RESULTS

The prevalence rates of CKD_GFR, CKD_ACR, and CKD_Risk were 2.2%, 6.7%, and 8.1%, respectively. Compared with the normal body mass index (BMI; 18.5-22.9 kg/m²) group, men with BMI ≥ 25 kg/m² had 1.88 times greater risk of CKD_GFR in the adjusted model [95% confidence interval (CI), 1.26-2.80; P = 0.002]; BMI was not significantly associated with CKD_GFR in women. In contrast, both men and women with BMI ≥ 25 kg/m² had 1.58 and 1.40 times higher risk of CKD_ACR (95% CI, 1.21-2.07 and 1.08-1.81, respectively, both P < 0.01). Obese men and women had 1.65 and 1.38 times higher risk of CKD_Risk (95% CI, 1.29-2.12 and 1.09-1.75, respectively, both P < 0.01).

CONCLUSIONS

Obesity was significantly associated with an increased ACR-based CKD risk. Longitudinal studies are needed to investigate the role of overweight and obesity in the development and progression of CKD.

Discrepancies between leg-to-leg bioelectrical Impedance analysis and computerized tomography in abdominal visceral fat measurement

The aim of this study was to evaluate leg-to-leg bioelectrical impedance analysis (LBIA) using a four-contact electrode system for measuring abdominal visceral fat area (VFA). The present study recruited 381 (240 male and 141 female) Chinese participants to compare VFA measurements estimated by a standing LBIA system (VFALBIA) with computerized tomography (CT) scanned at the L4-L5 vertebrae (VFA_CT). The total mean body mass index (BMI) was 24.7 ± 4.2 kg/m². Correlation analysis, regression analysis, Bland-Altman plot, and paired sample t-tests were used to analyze the accuracy of the VFA_LBIA. For the total subjects, the regression line was VFA_LBIA = 0.698 VFA_CT + 29.521, (correlation coefficient (r) = 0.789, standard estimate of error (SEE) = 24.470 cm², p < 0.001), Lin's correlation coefficient (CCC) was 0.785; and the limit of agreement (LOA; mean difference ±2 standard deviation) ranged from -43.950 to 67.951 cm², LOA% (given as a percentage of mean value measured by the CT) was 48.2%. VFA_LBIA and VFA_CT showed significant difference (p < 0.001). Collectively, the current study indicates that LBIA has limited potential to accurately estimate visceral fat in a clinical setting.

Pathophysiology and Potential Non-Pharmacologic Treatments of Obesity or Kidney Disease Associated Refractory Hypertension

PURPOSE OF REVIEW

The review assesses the role of non-pharmacologic therapy for obesity and chronic kidney disease (CKD) associated refractory hypertension (rf HTN).

RECENT FINDINGS

Hypertensive patients with markedly heightened sympathetic nervous system (SNS) activity are prone to develop refractory hypertension (rfHTN). Patients with obesity and chronic kidney disease (CKD)-associated HTN have particularly heightened SNS activity and are at high risk of rfHTN. The role of bariatric surgery is increasingly recognized in treatment of obesity. Current evidence advocates for a greater role of bariatric surgery in the management of obesity-associated HTN. In contrast, renal denervation does not appear have a role in the management of obesity or CKD-associated HTN. The role of baroreflex activation as adjunctive anti-hypertensive therapy remains to be defined.

Obesity-Induced Hypertension: Brain Signaling Pathways

Obesity greatly increases the risk for cardiovascular, metabolic, and renal diseases and is one of the most significant and preventable causes of increased blood pressure (BP) in patients with essential hypertension. This review highlights recent advances in our understanding of central nervous system (CNS) signaling pathways that contribute to the etiology and pathogenesis of obesity-induced hypertension. We discuss the role of excess adiposity and activation of the brain leptin-melanocortin system in causing increased sympathetic activity in obesity. In addition, we highlight other potential brain mechanisms by which increased weight gain modulates metabolic and cardiovascular functions. Unraveling the CNS mechanisms responsible for increased sympathetic activation and hypertension and how circulating hormones activate brain signaling pathways to control BP offer potentially important therapeutic targets for obesity and hypertension.

Acute Kidney Disease After Total Hip and Knee Arthroplasty: Incidence and Associated Factors

BACKGROUND

The development of acute kidney disease (AKD) following total joint arthroplasty has not been well characterized in the literature. We sought to calculate the incidence and identify risk factors associated with postoperative AKD for patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA).

METHODS

A total of 1000 consecutive cases (860 unique patients, including revisions) of TKA or THA performed between January 2010 and May 2016 were identified. Seventy-nine cases were excluded due to pre-existing kidney dysfunction and 23 additional cases were excluded due to incomplete data, resulting in 898 cases included in the study. There were 492 females and 406 males with a mean age of 58.1 years (range, 14-93 years). The Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease criteria and serum creatinine values were used to determine AKD status. Multiple logistic regression modeling was used to identify postoperative AKD risk factors.

RESULTS

Overall incidence of postoperative AKD was 6.8% (n = 61). Use of perioperative angiotensin receptor blocker (ARBs) or angiotensin-converting enzyme inhibitors (ACEi) (odds ratio [OR] = 2.09; P = .030), increasing body mass index (BMI) (OR = 1.58 per 10 kg/m²; P = .014), and use of vancomycin perioperatively (OR = 1.91; P = .021) were associated with increased odds of development of postoperative AKD.

CONCLUSION

A 6.8% incidence rate of postoperative AKD was noted in patients undergoing TKA or THA. Perioperative use of ARBs/ACEi, perioperative vancomycin use, and increased BMI were associated with increased odds of postoperative AKD.

Effect of bariatric surgery on adiposity and metabolic profiles: A prospective cohort study in Middle-Eastern patients

AIM

To investigate changes in adiposity and cardio-metabolic risk profile following Roux-en-Y gastric bypass in patients of Middle Eastern ethnicity with severe obesity.

METHODS

This prospective cohort study involved 92 patients who met the indications of bariatric surgery. Post-procedure markers of obesity and cardiometabolic profile were monitored regularly for a year.

RESULTS

Mean body mass index decreased by 29.5% from 41.9 to 29.5 kg/m2 between baseline and 12-mo follow-up, while mean fat mass decreased by 45.9% from 64.2 kg to 34.7 kg. An improvement was also observed in the gluco-metabolic profile with both fasting glucose and HbA1c substantially decreasing (P < 0.001).

CONCLUSION

The present study shows the short to medium term (1 year) health benefits of bariatric surgery for patients of Middle Eastern ethnicity.

Ameliorative Effect of Ecklonia cava Polyphenol Extract on Renal Inflammation Associated with Aberrant Energy Metabolism and Oxidative Stress in High Fat Diet-Induced Obese Mice

Immoderate fat accumulation causes both oxidative stress and inflammation, which can induce kidney damage in obesity. Previously, Ecklonia cava has shown anti-inflammatory and antioxidative effects. Our group aimed to investigate whether E. cava polyphenol extract (ECPE) improves renal damage in high fat diet (HFD)-induced obese mice through regulation of not only energy metabolism but also oxidative stress and inflammation. After obesity induction by HFD, the mice were treated with different dosages of ECPE (100 or 500 mg/kg/day) by gavage for 12 weeks. ECPE treatment lowered the protein levels related to lipid accumulation (SREBP1c, ACC & FAS), inflammation (NLRP3 inflammasome, NFκB, MCP-1, TNF-α & CRP), and oxidative stress (Nrf2, HO-1, MnSOD, NQO1, GPx, 4-HNE and protein carbonyls) in HFD induced obese mice. Moreover, ECPE supplementation significantly up-regulated renal SIRT1, PGC-1α, and AMPK, which are associated with renal energy metabolism. Consequently, the results provide novel insights into the anti-inflammatory roles of ECPE in obesity-induced renal inflammation.

The metabolic syndrome and chronic kidney disease

The metabolic syndrome (MetS) is a cluster of cardiovascular risk factors including insulin resistance (IR), dyslipidemia, and hypertension, which may also foster development of chronic kidney disease. The mechanisms of MetS-induced kidney disease are not fully understood. The purpose of this review is to summarize recent discoveries regarding the impact of MetS on the kidney, particularly on the renal microvasculature and cellular mitochondria. Fundamental manifestations of MetS include IR and adipose tissue expansion, the latter promoting chronic inflammation and oxidative stress that exacerbate IR. Those in turn can elicit various kidney injurious events through endothelial dysfunction, activation of the renin-angiotensin-aldosterone system, and adipokine imbalance. Inflammation and IR are also major contributors to microvascular remodeling and podocyte injury. Hence, these events may result in hypertension, albuminuria, and parenchymal damage. In addition, dyslipidemia and excessive nutrient availability may impair mitochondrial function and thereby promote progression of kidney cell damage. Elucidation of the link between MetS and kidney injury may help develop preventative measures and possibly novel therapeutic targets to alleviate and avert development of renal manifestations.

Occupational exposure to respirable crystalline silica and chronic non-malignant renal disease: systematic review and meta-analysis

Background

While occupational exposure to respirable silica is known to lead to lung disease, most notably silicosis, its association with chronic kidney disease is unclear.

Objectives

This review explores the association between occupational exposure to respirable silica and chronic non-malignant renal disease such as glomerulonephritis. The evidence has been collected and compiled. Possible sources of bias are thoroughly discussed.

Methods

Cohort studies with silica exposure and case–control studies of renal disease were searched in PubMed until January 2015. Two authors independently abstracted data; any disagreement was resolved by consulting a third reviewer. A meta-analysis was performed to evaluate the association to silica exposure.

Results

A total of 23 cohort and four case–control studies were included in the analysis. The meta-analysis of cohort studies yielded elevated overall SMRs for renal disease. Some studies, however, included dose–response analyses, most of which did not show a positive trend. The approaches and results of the case–control studies were very heterogeneous.

Conclusions

While the studies of cohorts exposed to silica found elevated SMRs for renal disease, no clear evidence of a dose–response relationship emerged. The elevated risk may be attributed to diagnostic and methodological issues. In order to permit a reliable estimation of a possible causal link, exposed cohorts should be monitored for renal disease, as the information from mortality studies is hardly reliable in this field.

Electronic supplementary material

The online version of this article (doi:10.1007/s00420-017-1219-x) contains supplementary material, which is available to authorized users.

Homocysteine levels and risk of essential hypertension: A meta-analysis of published epidemiological studies

BACKGROUND

Plasma homocysteine (Hcy) levels may be associated with essential hypertension (EH). However, the results of previous studies on this association are inconsistent.

METHODS

In this meta-analysis, we performed a systematic literature search of the Embase, PubMed, Cochrane Library, and Web of Science for the relevant articles dated up to March 2016. Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used to evaluate the estimates.

RESULTS

We included 11 studies with a total of 16,571 participants (4,830 EH cases). We found that elevated Hcy levels were associated with the risk of EH (pooled OR: 1.36, 95% CI: 1.02-1.80 in the random-effects model). However, subsequent subgroup analyses showed that elevated Hcy levels increased the EH risk in retrospective studies (OR: 1.82, 95% CI: 1.53-2.16; p < 0.001) and unadjusted studies (OR: 1.72, 95% CI: 1.43-2.07; p < 0.001), but not in perspective studies (OR: 0.99, 95% CI: 0.73-1.28; p = 0.939) and adjusted studies (OR: 1.21, 95% CI: 0.85-1.72; p = 0.297). No significant publication bias was found (p = 0.876 for Begg's test, p = 0.144 for Egger's test).

CONCLUSION

Plasma Hcy levels are associated with EH risk. However, our findings do not support a causal association between Hcy levels and EH.

The renal consequences of maternal obesity in offspring are overwhelmed by postnatal high fat diet

AIMS/HYPOTHESIS

Developmental programming induced by maternal obesity influences the development of chronic disease in offspring. In the present study, we aimed to determine whether maternal obesity exaggerates obesity-related kidney disease.

METHODS

Female C57BL/6 mice were fed high-fat diet (HFD) for six weeks prior to mating, during gestation and lactation. Male offspring were weaned to normal chow or HFD. At postnatal Week 8, HFD-fed offspring were administered one dose streptozotocin (STZ, 100 mg/kg i.p.) or vehicle control. Metabolic parameters and renal functional and structural changes were observed at postnatal Week 32.

RESULTS

HFD-fed offspring had increased adiposity, glucose intolerance and hyperlipidaemia, associated with increased albuminuria and serum creatinine levels. Their kidneys displayed structural changes with increased levels of fibrotic, inflammatory and oxidative stress markers. STZ administration did not potentiate the renal effects of HFD. Though maternal obesity had a sustained effect on serum creatinine and oxidative stress markers in lean offspring, the renal consequences of maternal obesity were overwhelmed by the powerful effect of diet-induced obesity.

CONCLUSION

Maternal obesity portends significant risks for metabolic and renal health in adult offspring. However, diet-induced obesity is an overwhelming and potent stimulus for the development of CKD that is not potentiated by maternal obesity.

Postnatal treatment with metyrapone attenuates the effects of diet-induced obesity in female rats exposed to early-life stress

Experimental studies in rodents have shown that females are more susceptible to exhibiting fat expansion and metabolic disease compared with males in several models of fetal programming. This study tested the hypothesis that female rat pups exposed to maternal separation (MatSep), a model of early-life stress, display an exacerbated response to diet-induced obesity compared with male rats. Also, we tested whether the postnatal treatment with metyrapone (MTP), a corticosterone synthase inhibitor, would attenuate this phenotype. MatSep was performed in WKY offspring by separation from the dam (3 h/day, postnatal days 2-14). Upon weaning, male and female rats were placed on a normal (ND; 18% kcal fat) or high-fat diet (HFD; 60% kcal fat). Nondisturbed littermates served as controls. In male rats, no diet-induced differences in body weight (BW), glucose tolerance, and fat tissue weight and morphology were found between MatSep and control male rats. However, female MatSep rats displayed increased BW gain, fat pad weights, and glucose intolerance compared with control rats (P < 0.05). Also, HFD increased plasma corticosterone (196 ± 51 vs. 79 ± 18 pg/ml, P < 0.05) and leptin levels (1.8 ± 0.4 vs. 1.3 ± 0.1 ng/ml, P < 0.05) in female MatSep compared with control rats, whereas insulin and adiponectin levels were similar between groups. Female control and MatSep offspring were treated with MTP (50 µg/g ip) 30 min before the daily separation. MTP treatment significantly attenuated diet-induced obesity risk factors, including elevated adiposity, hyperleptinemia, and glucose intolerance. These findings show that exposure to stress hormones during early life could be a key event to enhance diet-induced obesity and metabolic disease in female rats. Thus, pharmacological and/or behavioral inflection of the stress levels is a potential therapeutic approach for prevention of early life stress-enhanced obesity and metabolic disease.

Glomerular Hyperfiltration in Diabetes: Mechanisms, Clinical Significance, and Treatment

An absolute, supraphysiologic elevation in GFR is observed early in the natural history in 10%-67% and 6%-73% of patients with type 1 and type 2 diabetes, respectively. Moreover, at the single-nephron level, diabetes-related renal hemodynamic alterations-as an adaptation to reduction in functional nephron mass and/or in response to prevailing metabolic and (neuro)hormonal stimuli-increase glomerular hydraulic pressure and transcapillary convective flux of ultrafiltrate and macromolecules. This phenomenon, known as glomerular hyperfiltration, classically has been hypothesized to predispose to irreversible nephron damage, thereby contributing to initiation and progression of kidney disease in diabetes. However, dedicated studies with appropriate diagnostic measures and clinically relevant end points are warranted to confirm this assumption. In this review, we summarize the hitherto proposed mechanisms involved in diabetic hyperfiltration, focusing on ultrastructural, vascular, and tubular factors. Furthermore, we review available evidence on the clinical significance of hyperfiltration in diabetes and discuss currently available and emerging interventions that may attenuate this renal hemodynamic abnormality. The revived interest in glomerular hyperfiltration as a prognostic and pathophysiologic factor in diabetes may lead to improved and timely detection of (progressive) kidney disease, and could provide new therapeutic opportunities in alleviating the renal burden in this population.

Normotension, hypertension and body fluid regulation: brain and kidney

The fraction of hypertensive patients with essential hypertension (EH) is decreasing as the knowledge of mechanisms of secondary hypertension increases, but in most new cases of hypertension the pathophysiology remains unknown. Separate neurocentric and renocentric concepts of aetiology have prevailed without much interaction. In this regard, several questions regarding the relationships between body fluid and blood pressure regulation are pertinent. Are all forms of EH associated with sympathetic overdrive or a shift in the pressure-natriuresis curve? Is body fluid homoeostasis normally driven by the influence of arterial blood pressure directly on the kidney? Does plasma renin activity, driven by renal nerve activity and renal arterial pressure, provide a key to stratification of EH? Our review indicates that (i) a narrow definition of EH is useful; (ii) in EH, indices of cardiovascular sympathetic activity are elevated in about 50% of cases; (iii) in EH as in normal conditions, mediators other than arterial blood pressure are the major determinants of renal sodium excretion; (iv) chronic hypertension is always associated with a shift in the pressure-natriuresis curve, but this may be an epiphenomenon; (v) plasma renin levels are useful in the analysis of EH only after metabolic standardization and then determination of the renin function line (plasma renin as a function of sodium intake); and (vi) angiotensin II-mediated hypertension is not a model of EH. Recent studies of baroreceptors and renal nerves as well as sodium intake and renin secretion help bridge the gap between the neurocentric and renocentric concepts.

Outcomes of Laparoscopic Gastric Greater Curvature Plication in Morbidly Obese Patients

BACKGROUND

Laparoscopic gastric greater curvature plication (LGGCP) is a restrictive bariatric procedure without gastrectomy. However, limited literature on effectiveness of gastric plication exists.

OBJECTIVES

We assessed LGGCP's efficacy, effects on associated comorbidities, safety and the rate of complications, and patient satisfaction with LGGCP's outcomes among morbidly obese patients.

METHOD

Analysis of retrospectively data collected from medical records of 26 patients who had undergone LGGCP at Hamad General Hospital, Qatar, during 2011-2012.

RESULTS

Most patients (92%) were Qatari nationals. The sample's mean age was 35.1 years. Mean duration of hospital stay was 3.9 ± 1.2 days. Mean preoperative BMI was 40.7 kg/m² that decreased at 2 years to 34.6 kg/m². LGGCP's effects on comorbidities were such that 7.6% of patients experienced resolutions of their comorbidities. There were no mortality or postoperative complications that required reoperation. Six patients (23%) were satisfied with the LGGCP's outcomes while 10 patients (38.5%) underwent sleeve gastrectomy subsequently.

CONCLUSION

LGGCP had acceptable short term weight loss results, exhibited almost no postoperative complications, and improved patients' comorbidities. Despite the durability of the gastric fold, some patients regained weight. Future research may assess the possibility of an increase in the gastric pouch size postplication associated with weight regain.

Obesity: A Perspective from Hypertension

The prevalence of obesity-related hypertension is high worldwide and has become a major health issue. The mechanisms by which obesity relates to hypertensive disease are still under intense research scrutiny, and include altered hemodynamics, impaired sodium homeostasis, renal dysfunction, autonomic nervous system imbalance, endocrine alterations, oxidative stress and inflammation, and vascular injury. Most of these contributing factors interact with each other at multiple levels. Thus, as a multifactorial and complex disease, obesity-related hypertension should be recognized as a distinctive form of hypertension, and specific considerations should apply in planning therapeutic approaches to treat obese individuals with high blood pressure.

Matrix Metalloproteinase Neutrophil Gelatinase-Associated Lipocalin Complex Predicts Atrial Fibrillation Recurrence after Electrical Cardioversion in Obese Patients

BACKGROUND

There is not much data on matrix metalloproteinase neutrophil gelatinase-associated lipocalin (MMP-NGAL) complex in patients with atrial fibrillation (AF).

AIM

The aim of the study was to assess the value of MMP-NGAL complex in predicting AF recurrence after electrical cardioversion.

METHODS

The serum levels of NGAL, cystatin C, interleukin-6, high-sensitivity C-reactive protein, copeptin, MMP-NGAL complex, matrix metalloproteinase 2, tissue inhibitor of metalloproteinase 1, Von Willebrand factor, B-type natriuretic peptide and the urinary level of NGAL were evaluated before cardioversion.

RESULTS

A total of 83 patients with persistent AF were enrolled in the study. Left atrial diameter (LA) ≥4.5 cm was significantly associated with AF recurrence at follow-up (p = 0.009). In selected 39 obese patients, MMP-NGAL complex was associated with AF recurrence (p = 0.03). If the concentration of MMP-NGAL complex increased by 1 ng/ml, the odds of AF recurrence increased by 4% (OR 1.04; CI: 1.00-1.08; p = 0.03). MMP-NGAL complex did not correlate with AF recurrence in patients with a first episode of AF, in patients ≥65 years of age and in patients with a LA ≥4.5 cm or with chronic kidney disease.

CONCLUSIONS

It is known that the greater the BMI at baseline, the higher the likelihood of progression from paroxysmal to permanent AF. However, European Society of Cardiology (ESC) guidelines do not consider obese patients a population with a low likelihood of success of cardioversion. That is why we need a sensitive marker to predict sinus rhythm maintenance in such a population. We found that MMP-NGAL complex may predict AF recurrence after successful cardioversion in obese patients.

Body habitus in heart failure: understanding the mechanisms and clinical significance of the obesity paradox

The prevalence of obesity among adults and children worldwide has reached epic proportions and has become a major independent risk factor for the development of heart failure (HF), in addition to a contributor of hypertension and cardiovascular disease. The implications of obesity in the development of HF involve adverse effects on cardiac structure and function. Despite all of this, in the setting of chronic HF, excess body mass is associated with improved clinical outcomes, demonstrating the presence of an obesity paradox. In this review, we will discuss the gender differences, global application, potential mechanisms and role of interventions based on fitness and purposeful weight loss as potential therapeutic strategies.

Role of the Renal Microcirculation in Progression of Chronic Kidney Injury in Obesity

BACKGROUND

Obesity is largely responsible for the growing incidence and prevalence of diabetes, cardiovascular and renal diseases. Current strategies to prevent and treat obesity and its consequences have been insufficient to reverse the ongoing trends. Lifestyle modification or pharmacological therapies often produce modest weight loss which is not sustained and recurrence of obesity is frequently observed, leading to progression of target organ damage in many obese subjects. Therefore, research efforts have focused not only on the factors that regulate energy balance, but also on understanding mechanisms of target organ injury in obesity. Summary and Key Message: Microvascular (MV) disease plays a pivotal role in progressive kidney injury from different etiologies such as hypertension, diabetes, and atherosclerosis, which are all important consequences of chronic obesity. The MV networks are anatomical units that are closely adapted to specific functions of nutrition and removal of waste in every organ. Damage of the small vessels in several tissues and organs has been reported in obesity and may increase cardio-renal risk. However, the mechanisms by which obesity and its attendant cardiovascular and metabolic consequences interact to cause renal MV injury and chronic kidney disease are still unclear, although substantial progress has been made in recent years. This review addresses potential mechanisms and consequences of obesity-induced renal MV injury as well as current treatments that may provide protection of the renal microcirculation and slow progressive kidney injury in obesity.

Ectopic Adipose Tissue Storage in the Left and the Right Renal Sinus is Asymmetric and Associated With Serum Kidney Injury Molecule-1 and Fibroblast Growth Factor-21 Levels Increase

OBJECTIVE

A potential mechanism by which obesity could promote hypertension and kidney diseases is through accumulation of adipose tissue in the renal sinus (RS). The aim of the study was to quantify RS and abdominal adipose tissue volumes and to evaluate serum kidney injury molecule (sKIM)-1 and fibroblast growth factor (FGF)-21 association with different adipose tissue compartments.

METHODS

The cross-sectional study included 280 and follow-up study-40 asymptomatic participants; aged 38.30±4.10. For all study participants computed tomography examination was performed, sKIM-1 and FGF-21 levels were measured.

RESULTS

The results indicated asymmetrical deposition of adipose tissue into the RS even after corresponding kidney volume adjustment. The cross-sectional and the follow-up studies showed that sKIM-1 level was positively associated with RS adipose tissue volume increase for both genders. FGF-21 was positively associated with RS and retroperitoneal adipose tissue amount.

CONCLUSIONS

Regardless of gender adipose tissue in RS accumulates asymmetrically-the left RS accumulates a significantly higher amount of adipose tissue. Thus, primarily RS adipose tissue effects should be assessed on the left kidney. Accumulation of adipose tissue in the RS is related with the visceral adipose amount, KIM-1 and FGF-21 concentration increase in the blood serum.

Effects of Bariatric Surgery on Renal Function in Obese Patients: A Systematic Review and Meta Analysis

Background

Obesity is an independent risk factor of development and progression of chronic kidney disease (CKD). Data on the benefits of bariatric surgery in obese patients with impaired kidney function have been conflicting.

Objective

To explore whether there is improvement in glomerular filtration rate (GFR), proteinuria or albuminuria after bariatric surgery.

Methods

We comprehensively searched the databases of MEDLINE, Embase, web of science and Cochrane for randomized, controlled trials and observational studies that examined bariatric surgery in obese subjects with impaired kidney function. Outcomes included the pre- and post-bariatric surgery GFR, proteinuria and albuminuria. In obese patients with hyperfiltration, we draw conclusions from studies using measured GFR (inulin or iothalamate clearance) unadjusted for BSA only. Study quality was evaluated using the Newcastle-Ottawa Scale.

Results

32 observational studies met our inclusion criteria, and 30 studies were included in the meta-analysis. No matter in dichotomous data or in dichotomous data, there were statistically significant reduction in hyperfiltration, albuminuria and proteinuria after bariatric surgery.

Limitations

The main limitation of this meta-analysis is the lack of randomized controlled trials (RCTs). Another limitation is the lack of long-term follow-up.

Conclusions

Bariatric surgery could prevent further decline in renal function by reducing proteinuria, albuminuria and improving glomerular hyperfiltration in obese patients with impaired renal function. However, whether bariatric surgery reverses CKD or delays ESRD progression is still in question, large, randomized prospective studies with a longer follow-up are needed.

Comparison of Standing Posture Bioelectrical Impedance Analysis with DXA for Body Composition in a Large, Healthy Chinese Population

Bioelectrical impedance analysis (BIA) is a common method for assessing body composition in research and clinical trials. BIA is convenient but when compared with other reference methods, the results have been inconclusive. The level of obesity degree in subjects is considered to be an important factor affecting the accuracy of the measurements. A total of 711 participants were recruited in Taiwan and were sub-grouped by gender and levels of adiposity. Regression analysis and Bland-Altman analysis were used to evaluate the agreement of the measured body fat percentage (BF%) between BIA and DXA. The BF% measured by the DXA and BIA methods (Tanita BC-418) were expressed as BF%DXA and BF%BIA8, respectively. A one-way ANOVA was used to test the differences in BF% measurements by gender and levels of adiposity. The estimated BF%BIA8 and BF%DXA in the all subjects, male and female groups were all highly correlated (r = 0.934, 0.901, 0.916, all P< 0.001). The average estimated BF%BIA8 (22.54 ± 9.48%) was significantly lower than the average BF%DXA (26.26 ± 11.18%). The BF%BIA8 was overestimated in the male subgroup (BF%DXA< 15%), compared to BF%DXA by 0.45%, respectively. In the other subgroups, the BF%BIA8 values were all underestimated. Standing BIA estimating body fat percentage in Chinese participants have a high correlation, but underestimated on normal and high obesity degree in both male and female subjects.

Shp2 suppresses the adipogenic differentiation of preadipocyte 3T3-L1 cells at an early stage

Tyrosine phosphatase protein Shp2 is a potential therapeutic target for obesity. However, the mechanism of Shp2 during adipogenesis is not fully understood. The present study investigated the role of Shp2 in the terminal differentiation of preadipocytes. The results showed that Shp2 suppressed adipocyte differentiation in 3T3-L1 cells; overexpression of Shp2 reduced lipid droplet production in 3T3-L1 cells, whereas Shp2 knockdown increased lipid droplet production in 3T3-L1 cells. Furthermore, inhibition of Shp2 activity also enhanced adipocyte differentiation. Interestingly, Shp2 expression was specifically decreased early during differentiation in response to stimulation with the dexamethasone–methylisobutylxanthine–insulin (DMI) hormone cocktail. During the first 2 days of differentiation, Shp2 overexpression impaired the DMI-induced phosphorylation of signal transducer and activator of transcription 3 (STAT3) in 3T3-L1 cells and blocked the peak expression of CCAAT/enhancer-binding proteins β and δ during preadipocyte differentiation. In conclusion, Shp2 downregulated the early stages of hormone-induced differentiation of 3T3-L1 cells and inhibited the expression of the first wave of transcription factors by suppressing the DMI-induced STAT3 signaling pathway. These discoveries point to a novel role of Shp2 during adipogenesis and support the hypothesis that Shp2 could be a therapeutic target for the control of obesity.

Resveratrol ameliorates renal injury in spontaneously hypertensive rats by inhibiting renal micro-inflammation

Micro-inflammation plays an important role in the pathogenesis of spontaneously hypertensive rat (SHR). In the present study, we investigated the therapeutic potential of resveratrol (RSV), a polyphenol with anti-fibrosis activity in hypertensive renal damage model. In SHR renal damage model, RSV treatment blunted the increase in urine albumin excretion, urinary β2-microglobulin (β2-MG), attenuated the decrease in creatinine clearance rate (CCR). The glomerular sclerosis index (1.54±0.33 compared with 0.36±0.07) and tubulointerstitial fibrosis (1.57±0.31 compared with 0.19±0.04) were significantly higher in SHRs compared with Wistar Kyoto rats (WKYs), which were significantly lower by RSV treatment. The increases in mesangium accumulation and the expression of renal collagen type I (Col I), fibronectin (Fn), plasminogen activator inhibitor-1 (PAI-1) and transforming growth factor-β1 (TGF-β1) in SHR were also reduced by RSV treatment. Nuclear factor κB (NF-κB) expression was increased in the cytoplasm and nuclei of the SHR kidneys, which was significantly decreased by RSV treatment. Furthermore, the protein level of IκB-α significantly decreased in the kidneys of the SHR when compared with the WKYs. RSV treatment partially restored the decreased IκB-α level. In SHR kidney, increased expression of interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein 1 (MCP-1) were observed. These changes were attenuated by RSV treatment. No changes in blood pressure were detected between SHR group and SHR + RSV group. Taken together, the present study demonstrated that RSV treatment may significantly attenuate renal damage in the SHR model of chronic kidney disease (CKD). The renal protective effect is associated with inhibition of IL-6, ICAM-1 and MCP-1 expression via the regulation of the nuclear translocation of NF-κB, which suggesting that micro-inflammation may be a potential therapeutic target of hypertensive renal damage.

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.

Role of adipocytes in hypertension

Although it has known for some time that obesity is associated with salt sensitivity and hypertension, recent data suggests that the adipocyte may actually be the proximate cause of this physiological changes. In the following review, the data demonstrating this association as well as the potentially operative pathophysiological mechanisms are reviewed and discussed.

Tacrolimus Modulates TGF-β Signaling to Induce Epithelial-Mesenchymal Transition in Human Renal Proximal Tubule Epithelial Cells

Epithelial-mesenchymal transition (EMT), a process which describes the trans-differentiation of epithelial cells into motile mesenchymal cells, is pivotal in stem cell behavior, development and wound healing, as well as contributing to disease processes including fibrosis and cancer progression. Maintenance immunosuppression with calcineurin inhibitors (CNIs) has become routine management for renal transplant patient, but unfortunately the nephrotoxicity of these drugs has been well documented. HK-2 cells were exposed to Tacrolimus (FK506) and EMT markers were assessed by RT PCR and western blot. FK506 effects on TGF-β mRNA were assessed by RT PCR and TGF-β secretion was measured by ELISA. The impact of increased TGF-β secretion on Smad signaling pathways was investigated. The impact of inhibition of TGF-β signaling on EMT processes was assessed by scratch-wound assay. The results presented in this study suggest that FK506 initiates EMT processes in the HK-2 cell line, with altered expression of epithelial and myofibroblast markers evident. Additionally, the study demonstrates that FK506 activation of the TGF-β/ SMAD pathways is an essential step in the EMT process. Overall the results demonstrate that EMT is heavily involved in renal fibrosis associated with CNI nephrotoxicity.

Effect of GLP-1 Receptor Activation on Offspring Kidney Health in a Rat Model of Maternal Obesity

Maternal obesity is associated with an increased risk of chronic disease in offspring, including type 2 diabetes (T2D). Exendin-4 (Exd-4) activates the glucagon like peptide-1 (GLP-1) receptor thereby decreasing serum glucose levels and body weight. In addition, Exd-4 has been shown to reduce renal and cardiac complications in experimental models of T2D. We hypothesized that treatment with Exd-4 would ameliorate the detrimental effects of maternal and diet-induced obesity on renal characteristics in offspring. Female Sprague-Dawley rats were fed either normal or high-fat diet (HFD) for 6 weeks prior to pregnancy, during pregnancy and lactation, and their offspring were weaned to normal or HFD. The offspring were randomized to Exd-4 or placebo from weaning and their kidneys harvested at Week 9. We found that the kidneys of offspring from obese mothers, regardless of postnatal diet, had significantly increased markers of inflammation, oxidative stress and fibrosis. Exd-4 ameliorated the negative renal effects of maternal obesity and in particular, reduced renal inflammation, oxidative stress and fibrosis. In conclusion, maternal obesity has persisting effects on renal structure in the offspring. GLP-1 analogues are potentially useful for protecting against the deleterious effects of maternal obesity on renal physiology in offspring.