Impact of treating the metabolic syndrome on chronic kidney disease

Prevalence and risk factors of kidney stone disease in population aged 40-70 years old in Kharameh cohort study: a cross-sectional population-based study in southern Iran

BACKGROUND

Kidney stone is the major cause of morbidity, and its prevalence is increasing in the world. This study aimed to assess the prevalence and risk factors of kidney stone in the adult population of southern Iran based on the data of the Kharameh Cohort Study.

METHODS

This cross-sectional study was conducted on 10,663 individuals aged 40-70 years old, using the baseline data of Kharamah cohort study, which started in 2014. Among all participants, 2251 individuals had a history of kidney stone. The participants' demographic characteristics, behavioral habits, and the history of underlying diseases were investigated. The crude and Age Standardized Prevalence Rate of kidney stones was calculated. Also, logistic regression was used to identify the predictors of kidney stone. To check the goodness of fit index of the model, we used the Hosmer-Lemeshow test. All analyses were performed in STATA software.

RESULTS

The prevalence of kidney stone was estimated 21.11%. Also, the Age Standardized Prevalence Rate in men and women was calculated 24.3% and 18.7%, respectively. The mean age of the participants was 52.15 years. Higher prevalence of kidney stone was seen in women aged 40-50 years (40.47%, p = 0.0001) and moderate level of social economic status (31.47%, p = 0.03), men with overweight (44.69%, p < 0.0001) and those in a very high level of social economic status (35.75%, p = 0.001). The results of multiple logistic regression showed that the chance of having kidney stone was 1.17 times higher in diabetic individuals, 1.43 times higher in hypertensive individuals, 2.21 times higher in individuals with fatty liver, and 1.35 times higher in individuals with overweight. The level of socio economic status, male sex, and age were the other factors related to kidney stone.

CONCLUSION

In this study, underlying diseases such as fatty liver, diabetes, and hypertension as well as age, male sex, overweight, and high social economic status were identified as important risk factors for kidney stone. Therefore, identifying individuals at risk of kidney stone and providing the necessary training can greatly help to reduce this disease. However, health policymakers should prepare preventive strategies to reduce the occurrence of kidney stone.

Metabolic Syndrome-Related Kidney Injury: A Review and Update

Metabolic syndrome (MetS) includes visceral obesity, hyperglycemia, dyslipidemia, and hypertension. The prevalence of MetS is 20-25%, which is an important risk factor for chronic kidney disease (CKD). MetS causes effects on renal pathophysiology, including glomerular hyperfiltration, RAAS, microalbuminuria, profibrotic factors and podocyte injury. This review compares several criteria of MetS and analyzes their differences. MetS and the pathogenesis of CKD includes insulin resistance, obesity, dyslipidemia, inflammation, oxidative stress, and endothelial dysfunction. The intervention of MetS-related renal damage is the focus of this article and includes controlling body weight, hypertension, hyperglycemia, and hyperlipidemia, requiring all components to meet the criteria. In addition, interventions such as endoplasmic reticulum stress, oxidative stress, gut microbiota, body metabolism, appetite inhibition, podocyte apoptosis, and mesenchymal stem cells are reviewed.

Vitamin D3 potentiates the nephroprotective effects of vildagliptin-metformin combination in a rat model of metabolic syndrome

The current study was conducted to investigate the nephroprotective effects of vildagliptin-metformin combination in an experimental model of fructose/salt-induced metabolic syndrome (MetS). A major aim was to evaluate the potential capacity of vitamin D3 to potentiate the pleiotropic nephroprotective effects of vildagliptin-metformin combination. MetS was induced in adult male Wistar rats by adding fructose (10%) to everyday drinking water and salt (3%) to the diet for 6 weeks. Along with the same concentrations of fructose/salt feeding, MetS rats were then treated orally with either vildagliptin (10 mg/kg/day)-metformin (200 mg/kg/day) combination, vitamin D3 (10 μg/kg/day), or the triple therapy for a further 6 weeks. The incidence of MetS was confirmed 6 weeks after fructose/salt consumption, when the rats exhibited significant weight gain, dyslipidemia, hyperuricemia, insulin resistance, hyperinsulinemia, and impaired glucose tolerance. At the end of the 12-week experimental period, MetS rats displayed significantly deteriorated renal function, enhanced intrarenal oxidative stress and inflammation together with exaggerated renal histopathological damages and interstitial fibrosis. The study has corroborated antioxidant, anti-inflammatory, and antifibrotic effects of vildagliptin-metformin combination, vitamin D3, and the triple collaborative therapy, conferring renoprotection in the setting of MetS. Due attention has been paid to the crucial role of dipeptidyl peptidase-4 inhibition and sirtuin-1/5' adenosine monophosphate-activated protein kinase activation as novel therapeutic targets to optimize renoprotection. The apparent potentiating effect, evoked upon coadministration of vitamin D3 with vildagliptin-metformin combination, may provide a cornerstone for further clinical investigations.

NLRP3 Inflammasome in Metabolic-Associated Kidney Diseases: An Update

Metabolic syndrome (MS) is a group of complex metabolic disorders syndrome, which refers to the pathological state of metabolism disorder of protein, fat, carbohydrate and other substances in human body. The kidney is an important organ of metabolism, and various metabolic disorders can lead to the abnormalities in the structure and function of the kidney. The recognition of pathogenesis and treatment measures of renal damage in MS is a very important part for the renal function preserve. Inflammatory response caused by various metabolic factors is a protective mechanism of the body, but persistent inflammation will become a harmful factor and aggravate kidney damage. Inflammasomes are sensors of the innate immune system that play crucial roles in initiating inflammation in response to acute infections and chronic diseases. They are multiprotein complex composed of cytoplasmic sensors (mainly NLR family members), apoptosis-associated speck-like protein (ASC or PYCARD) and pro-caspase-1. After receiving exogenous and endogenous stimuli, the sensors begin to assemble inflammasome and then promote the release of inflammatory cytokines IL-1β and IL-18, resulting in a special way of cell death named pyroptosis. In the kidney, NLRP3 inflammasome can be activated by a variety of pathways, which eventually leads to inflammatory infiltration, renal intrinsic cell damage and renal function decline. This paper reviews the function and specific regulatory mechanism of inflammasome in kidney damage caused by various metabolic disorders, which will provide a new therapeutic perspective and targets for kidney diseases.

Vagotomy associated with splenectomy reduces lipid accumulation and causes kidneys histological changes in rats with hypothalamic obesity

Purpose

To evaluate the influence of autonomic vagal and splenic activities on renal histomorphometric aspects in obese rats.

Methods

Thirty male Wistar rats were used, of which, 24 received subcutaneous injections of monosodium glutamate (MSG) during the first 5 days of life (4 g/kg body weight) and six control animals received injections of saline solution (CON). Five experimental groups were organized (n = 6/group): falsely-operated control (CON-FO); falsely-operated obese (MSG-FO); vagotomized obese (MSG-VAG); splenectomized obese (MSG-SPL); vagotomized and splenectomized obese (MSG-VAG-SPL).

Results

The MSG-FO group animals showed a significant reduction in body weight and nasal-anal length when compared to CON-FO group animals (p < 0.05). The MSG-VAG-SPL group showed significant reduced in most biometric parameters associated with obesity. Falsely-operated obese animals showed a significant reduction in renal weight, glomerular diameters, glomerular tuff and capsule areas and Bowman’s space compared to CON-FO group animals (p < 0.05). There was a significant reduction in diameter, glomerular tuft and capsule areas, and Bowman’s space in MSG-VAG, MSG-SPL, MSG-VAG-SPL groups when compared to the MSG-FO group.

Conclusions

Vagotomy associated with splenectomy induces a reduction in the adiposity and causes histological changes in the kidney of obese rats.

Metabolic Syndrome Rather than Obesity Alone Is More Significant for Kidney Disease

INTRODUCTION

Obesity is associated with metabolic syndrome, nonalcoholic steatohepatitis, and kidney disease. BMI may not be the ideal measure of obesity when used to assess its effect on kidney disease as it does not discriminate for age, sex, ethnicity, muscle, bone, or fat mass.

OBJECTIVES

To assess the prevalence microalbuminuria and identify independent risk factors for development of kidney disease in the obese Indian population.

METHODS

Age, weight, BMI, total body fat percentage, waist-to-hip ratio, hypertension, urinary albumin-to-creatinine ratio (UACR), and HbA1c were collected from 568 obese patients, presenting for bariatric surgery. Multivariate binary logistic regression was used to identify independent risk factors for kidney disease.

RESULTS

A total of 114 out of 568 (20.07%) obese patients had microalbuminuria (UACR range 30-283 μg/mg). HbA1C levels ≥ 6 (p = 0.01) and hypertension (p = 0.03) were the strongest independent variables for microalbuminuria. 14.67% with a BMI < 35 kg/m², 21.30% with a BMI 35-50 kg/m², and 19.44% with a BMI > 50 kg/m² had microalbuminuria. Increasing BMI however was not statistically significant (p = 0.75). Total body fat percentage (p = 0.51), waist-to-hip ratio (p = 0.96), age (p = 0.30), sex (p = 0.38), and BMI (p = 0.75) were found to be statistically insignificant.

CONCLUSIONS

Kidney disease afflicts 1/5th of the obese Indian patients studied. Diabetes and hypertension remained as the most significant risk factors, while age, weight, increasing BMI, waist-to-hip ratio, or increasing body fat were found to be statistically insignificant for development and progression of kidney disease.

The association between a non-invasive hepatic fibrosis score and urolithiasis among non-alcoholic fatty liver disease (NAFLD) patients in China: a cross-sectional study

OBJECTIVE

Mounting data now support a strong link between the presence of non-alcoholic fatty liver disease (NAFLD) and an increased risk of urolithiasis. However, little is known on the association between hepatic fibrosis and the risk of urolithiasis among NAFLD patients. Therefore, this study aimed to investigate the prevalence of urolithiasis among NAFLD patients and determine whether the Fibrosis-4 (FIB-4) score, a surrogate marker of hepatic fibrosis, is associated with urolithiasis among NAFLD patients.

DESIGN

Cross-sectional studies.

SETTING

China.

METHODS

A total of 2058 adult patients with NAFLD were included in this study. Logistic regression analysis was used to detect the association between FIB-4 score and urolithiasis. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic value of FIB-4 score for the detection of urolithiasis among NAFLD patients.

RESULTS

200 (9.7%) individuals had ultrasonography-diagnosed urolithiasis among 2058 NAFLD patients. FIB-4 score (OR=1.58; 95% CI 1.06 to 2.31), age (OR=1.11; 95% CI 1.08 to 1.13), obesity (OR=3.16; 95% CI 2.29 to 4.39) and hyperuricemia (OR=3.79; 95% CI 2.67 to 5.36) were independent factors associated with urolithiasis among NAFLD patients. Moreover, a novel algorithm including multiple variables (FIB-4 score, age, obesity and hyperuricemia) showed an area under a ROC curve of 0.813 (95% CI 0.795 to 0.829) for identifying urolithiasis among NAFLD patients. The optimal cut-off value of > -2.23 for the multivariate model provides a sensitivity of 76% and a specificity of 74% for predicting urolithiasis among NAFLD patients.

CONCLUSION

Urolithiasis among NAFLD patients is associated with FIB-4 score. Further, a novel algorithm based on FIB-4 score could serve as a useful tool for identifying individuals with a higher risk of urolithiasis among NAFLD patients, although prospective cohort studies are still needed in the future.

Lankarani K. Relationships Between Various Components of Metabolic Syndrome and Chronic Kidney Disease in Shiraz, Iran

BACKGROUND

Chronic kidney disease (CKD) can potentially be associated with metabolic syndrome (MetS).

OBJECTIVES

We aimed to determine the association of MetS and the number of metabolic syndrome components with the risk of CKD in the Iranian population in southern Iran.

METHODS

A total of 819 subjects aged 18 - 88 years were enrolled using weight-based random cluster sampling. We constructed a logistic regression model to determine the adjusted odds ratios (ORs) and 95% confidence intervals (CI) of the association of MetS individual components and the number of these components with CKD.

RESULTS

The prevalence rate of MetS was 25.9% (30.9% in women and 18.8% in men). CKD was present in 16.6% of the participants (men: 14% and women: 19.4%). The most prevalent component was abdominal obesity (63.6%), followed by low HDL cholesterol (36.7%), high triglyceride level (31.7%), hypertension (25.6%) and high fasting blood sugar (21.9%). Central obesity and low HDL level were observed to be more prevalent among women (P < 0.001). The presence of MetS was associated with CKD with an increased OR for CKD (OR: 3.07, 95% CI 2.09 - 4.50; P < 0.001). The adjusted ORs (95% CI) were 1.189 (0.554 - 2.555), 2.025 (0.990 - 4.141) and 4.769 (2.413 - 9.424) as the number of risk factors increased from 1 to ≥ 3. Individuals with hypertension and abdominal obesity had a higher OR of increased susceptibility to CKD in multivariate analysis.

CONCLUSIONS

Our study indicated a strong association between CKD and MetS in the Iranian population. It is also suggested that individuals with metabolic risk factors should be detected earlier; they should also undergo multidisciplinary interventions to hinder worsening of the individual components of MetS and development of CKD.

Non-alcoholic fatty liver disease and the risk of urolithiasis: A systematic review and meta-analysis

There is growing evidence that nonalcoholic fatty liver disease (NAFLD) is associated with a higher risk of urolithiasis, but it has not yet been determined that this association is reproducible and consistent across different studies. We performed a systematic review and meta-analysis of these studies to examine the association between NAFLD and the risk of urolithiasis.We searched PubMed, EMBASE, and Google scholar using terms "fatty liver" (OR "non-alcoholic fatty liver disease" OR "non-alcoholic steatohepatitis" OR "NAFLD" OR "NASH") AND "urolithiasis" (OR "nephrolithiasis" OR "kidney stone" OR "urinary calculi" OR "renal colic" OR "urologic disease"). Observational studies in which NAFLD and urolithiasis were diagnosed by either ultrasonography or computerized tomography were included.A total of 7 observational studies with 226,541 individuals (24.7% with NAFLD) and 19,184 urolithiasis (8.5%). NAFLD was significantly associated with an increased risk of urolithiasis (random effect odds ratio, OR 1.73, 95% confidence interval, CI 1.24-2.40, I=94.5%). Sensitivity analyses revealed the robustness of the results. Egger test and Begg test suggested no publication bias (P > .05).NAFLD is associated with an increased risk of urolithiasis. Therefore, patients with NAFLD should be carefully monitored for the development of urolithiasis.

Metabolic Syndrome Severity and Risk of CKD and Worsened GFR: The Jackson Heart Study

BACKGROUND/AIMS

The metabolic syndrome (MetS), as assessed using dichotomous criteria, is associated with increased risk of future chronic kidney disease (CKD), though this relationship is unclear among African Americans, who have lower risk for MetS but higher risk for CKD.

METHODS

We performed logistic regression using a sex- and race-specific MetS-severity z-score to assess risk of incident CKD among 2,627 African-American participants of the Jackson Heart Study, assessed at baseline and 8 years later. Based on quartile of baseline MetS severity, we further assessed prevalence of being in the lowest quartile of baseline GFR, the lowest quartile of relative GFR at follow-up, microalbuminuria and incident CKD.

RESULTS

Higher MetS-severity was associated with higher prevalence of GFR in the lowest quartile at baseline among males and females. Among African-American females but not males, higher baseline MetS-severity was associated with a higher prevalence of baseline elevations in microabuminuria (p<0.01), steep decline in GFR (p<0.001) and a higher incidence of CKD (p<0.0001). Women in increasing quartiles of baseline MetS-severity exhibited a linear trend toward higher odds of future CKD (p<0.05), with those in the 4th quartile of MetS-severity (compared to the 1st) having an odds ratio of 2.47 (95% confidence interval 1.13, 5.37); no such relationship was seen among men (p value for trend 0.49).

CONCLUSION

MetS-severity exhibited sex-based interactions regarding risk for future GFR deterioration and CKD, with increasing risk in women but not men. These data may have implications for triggering CKD screening among African-American women with higher degrees of MetS-severity.

Deletion of NLRX1 increases fatty acid metabolism and prevents diet-induced hepatic steatosis and metabolic syndrome

NOD-like receptor (NLR)X1 (NLRX1) is an ubiquitously expressed inflammasome-independent NLR that is uniquely localized in mitochondria with as yet unknown effects on metabolic diseases. Here, we report that NLRX1 is essential in regulating cellular metabolism in non-immune parenchymal hepatocytes by decreasing mitochondrial fatty acid-dependent oxidative phosphorylation (OXPHOS) and promoting glycolysis. NLRX1 loss in mice has a profound impact on the prevention of diet-induced metabolic syndrome parameters, non-alcoholic fatty liver disease (NAFLD) progression, and renal dysfunction. Despite enhanced caloric intake, NLRX1 deletion in mice fed a western diet (WD) results in protection from liver steatosis, hepatic fibrosis, obesity, insulin resistance, glycosuria and kidney dysfunction parameters independent from inflammation. While mitochondrial content was equal, NLRX1 loss in hepatocytes leads to increased fatty acid oxidation and decreased steatosis. In contrast, glycolysis was decreased in NLRX1-deficient cells versus controls. Thus, although first implicated in immune regulation, we show that NLRX1 function extends to the control of hepatocyte energy metabolism via the restriction of mitochondrial fatty acid-dependent OXPHOS and enhancement of glycolysis. As such NLRX1 may be an attractive novel therapeutic target for NAFLD and metabolic syndrome.

Cholecystectomy as a risk factor of metabolic syndrome: from epidemiologic clues to biochemical mechanisms

Cholecystectomy has long been regarded as a safe procedure with no deleterious influence on the body. However, recent studies provide clues that link cholecystectomy to a high risk for metabolic syndrome (MetS). In the present review, we describe the epidemiologic evidence that links cholecystectomy to MetS. Various components of MetS are investigated, including visceral obesity, dyslipidemia, elevated blood pressure, impaired fasting glucose, and insulin resistance. The possible mechanisms that associate cholecystectomy with MetS are discussed on the basis of experimental studies.

Association between non-invasively diagnosed hepatic steatosis and chronic kidney disease in Chinese adults on their health check-up

OBJECTIVE

To explore the association between chronic kidney disease (CKD), graded by the estimated glomerular filtration rate (eGFR), and non-alcoholic fatty liver disease (NAFLD) using controlled attenuation parameter (CAP) and fatty liver index (FLI) values in Chinese adults undergoing routine health examinations.

METHODS

A total of 731 adult participants without diabetes mellitus or significant alcohol consumption who underwent routine health examinations were included. Their eGFR, CAP, FLI and abdominal ultrasonography results were assessed.

RESULTS

The prevalence of ultrasound-diagnosed NAFLD and CKD (eGFR <60 mL/min per 1.73 m² ) was 36.1% and 6.6%, respectively. CKD was more common in NAFLD patients than in those without (10.6% vs 4.3%, P < 0.001). The CAP and FLI values were significantly higher in the NAFLD group than in those without, but the change in the eGFR was negligible between the two groups. eGFR was negatively correlated with CAP (r = -0.189, P = 0.003) and FLI values (r = -0.130, P = 0.045). Moreover, eGFR was significantly lower in participants with CAP >292 dBm or FLI ≥60 than in those with CAP <238 dBm or FLI <30, respectively (both P < 0.05). The CAP value (odds ratio [OR] 1.099, 95% confidence interval [CI] 1.091-1.108, P = 0.021) was an independent risk factor for CKD.

CONCLUSIONS

A diagnosis of hepatic steatosis is related to an increased risk of CKD among non-alcoholic and non-diabetic Chinese adults regardless of whether the diagnosis was acquired via ultrasound, CAP or FLI. Increased hepatic lipid content may contribute to CKD development.

An observational study on the association of nonalcoholic fatty liver disease and metabolic syndrome with gall stone disease requiring cholecystectomy

Objective

Recognition of Non alcoholic fatty liver disease (NAFLD) and metabolic syndrome in patients with gallstones undergoing laparoscopic or open cholecystectomy, along with it we will also study the life style of patients with gall stones.

Background

Patients with gallstones have associated NAFLD, with concurrent metabolic syndrome and these ailments share similar factors for example obesity, hypertriglyceridemia and diabetes mellitus. Factors like body mass index, gender, raised lipid levels, use of contraceptives and alcohol and having diabetes, physical inactiveness, multiparous women, water with excessive iron content, metabolic syndrome, and NAFLD are accountable factors for gallstones formation.

Methodology

This was a case series done at Surgical Unit 1 of Civil Hospital Karachi. Selective samples of 88 patients were included. Duration was 3 months. We included both sexes with ultrasound proof of gall stone irrespective of cholecystitis. Excluded patients with history of seropositive viral hepatitis, autoimmune and wilson's disease. As these conditions can act as a confounder to our variables.

Results

Nafld was present in 62.5%(n = 55) while 28.4% (n = 25) had metabolic syndrome. 26.94% had BMI less than 18, 32.12 had BMI between 18 and 25 and majority had BMI greater than 25 i.e in 40.93%. Of all 46.6% had a family history of cholelithiasis. Gallstone patients with NAFLD reported about their first degree relative being suffering from cholelithiasis at a significant p-value of 0.034 while this was not significant in cases of metabolic syndrome and the p -value was 0.190.

Conclusion

We found association of metabolic syndrome with gallstones and NAFLD. Non alcoholic fatty liver was highly prevalent in our study subjects. Huge percentage of first degree relatives of gall stone patients had gallstones and this relation was more pronounced patients who had associated NAFLD.

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Most patients with gallstones have associated NAFLD.

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Metabolic syndrome, NAFLD, gallstones share common factors.

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We recommend health education and lifestyle modification in gall stone patients.

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Majority first degree relatives of gall stone patients had gallstones.

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First degree relatives of patients had gallstones and this relation was more pronounced patients who had associated NAFLD.

Relationship between chronic kidney disease and metabolic syndrome: current perspectives

Both metabolic syndrome (MetS) and chronic kidney disease (CKD) are increasing in incidence and lead to significant cardiovascular morbidity and mortality. The relationship between these two entities is complex. Individual components of the MetS are known risk factors for incident kidney disease, but it is not clear how the clustering of these components is linked to the development and progression of kidney disease. Cross-sectional studies show an association of the MetS and prevalent CKD; however, one cannot draw conclusions as to which came first - the MetS or the kidney disease. Observational studies suggest a relationship between MetS and incident CKD, but they also demonstrate the development of MetS in patients with established CKD. These observations suggest a bidirectional relationship. A better understanding of the relationship between components of the MetS and whether and how these components contribute to progression of CKD and incident cardiovascular disease could inform more effective prevention strategies.

Change in albuminuria and eGFR following insulin sensitization therapy versus insulin provision therapy in the BARI 2D study

BACKGROUND AND OBJECTIVES

In the Bypass Angioplasty Revascularization Investigation 2 Diabetes randomized trial, glycemic control with insulin-sensitization therapy was compared with insulin-provision therapy in patients with type 2 diabetes and coronary artery disease. This study examined differences in albumin excretion and renal function in the insulin-sensitization group versus the insulin-provision group over 5 years.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

In total, 1799 patients with measurements of creatinine and urine albumin/creatinine ratio at baseline and at least two follow-up visits were included. Management of BP, lipids, and lifestyle counseling was uniform. Progression of albuminuria was defined as doubling of baseline albumin/creatinine ratio to at least 100 mg/g or worsening of albumin/creatinine ratio status on two or more visits. Worsening renal function was defined as >25% decline in estimated GFR and annualized decline of >3 ml/min per 1.73 m(2) per year.

RESULTS

By 6 months and thereafter, the mean glycated hemoglobin levels were lower in the insulin-sensitization group compared with the insulin-provision group (P<0.002 for each time point; absolute difference=0.4%). Albumin/creatinine ratio increased over time in the insulin-sensitization group (P value for trend<0.001) and was stable in the insulin-provision group. Risk for progression of albumin/creatinine ratio was higher in the insulin-sensitization group compared with the insulin-provision group (odds ratio, 1.59; 95% confidence interval, 1.25 to 2.02; P=0.02). Over 5 years, albumin/creatinine ratio increased from 11.5 (interquartile range=5.0-46.7) to 15.7 mg/g (interquartile range=6.2-55.4) in the insulin-sensitization group (P<0.001) and from 12.1 (interquartile range=5.3-41.3) to 12.4 mg/g (interquartile range=5.8-50.6) in the insulin-provision group (P=0.21). Estimated GFR declined from 75.0±20.6 to 66.3±22.6 ml/min per 1.73 m(2) in the insulin-sensitization group (P<0.001) and from 76.1±29.5 to 66.8±22.1 ml/min per 1.73 m(2) in the insulin-provision group (P<0.001).

CONCLUSION

Over 5 years, despite lower glycated hemoglobin levels, the insulin-sensitization treatment group had greater progression of albumin/creatinine ratio compared with the insulin-provision treatment group. Decline in estimated GFR was similar.

Metformin decreases high-fat diet-induced renal injury by regulating the expression of adipokines and the renal AMP-activated protein kinase/acetyl-CoA carboxylase pathway in mice

Metabolic syndrome is characterized by insulin resistance, dyslipidemia and hypertension. These metabolic changes contribute to the development of obesity-induced kidney injury. AMP-activated protein kinase (AMPK) is a ubiquitous enzyme that is involved in the cellular metabolic response to metabolic stress. Metformin, an AMPK activator, has been reported to exert a protective effect against non-alcoholic steatohepatitis. However, little is known about its role in the pathogenesis of obesity-induced renal injury. The aim of this study was to investigate the effects of metformin on high-fat diet (HFD)-induced kidney injury. Obesity was induced by HFD (60% of total calories from fat, 20% protein and 20% carbohydrates) in 6-week-old C57BL/6 mice. Mice were fed HFD plus 0.5% metformin. The effects of metformin on HFD-induced renal injury were evaluated by determining metabolic parameters, serum adipokine levels and renal AMPK/acetyl-CoA carboxylase (ACC) activities, as well as a histological examination. HFD induced metabolic derangement, systemic insulin resistance and glomerular mesangial matrix expansion. The administration of metformin reduced HFD-induced metabolic derangement and renal injury. The administration of metformin reduced the HFD-induced increase in adipokine expression and macrophage infiltration. Moreover, renal AMPK activity, which was decreased by HFD, was recovered following the administration of metformin; in addition, fatty acid oxidation was increased by the inhibition of ACC. These results indicate that metformin exerts beneficial effects on obesity-induced renal injury by regulating systemic inflammation, insulin resistance and the renal AMPK/ACC pathway. The clinical application of metformin to obese or early diabetic patients may be helpful in preventing obesity- or diabetes-related kidney disease.

The impact of a community trial on the pharmacological treatment in the individuals with the metabolic syndrome: findings from the Isfahan Healthy Heart Program, 2001-2007

INTRODUCTION

Pharmacological therapy is a crucial step in the management of individuals with the metabolic syndrome, when lifestyle modifications alone cannot achieve the therapeutic goals. The present study aimed to evaluate the efficacy of comprehensive interventions with the pharmacological treatment in individuals with the metabolic syndrome.

MATERIAL AND METHODS

A cross-sectional population-based survey examined a sample of adults before and after conducting a community trial. Physical examination and blood sampling, data regarding the demographic characteristics, medical status and history of medication use were obtained. Pharmacologic treatment related to metabolic syndrome's components was also determined.

RESULTS

The most common pharmacologic agents consumed by individuals with metabolic syndrome were β-blockers (26.1% and 30.4% in 2001 and 2007, respectively), followed by lipid-lowering agents (5.4% and 14% in 2001 and 2007, respectively), with significant differences before and after intervention. The prevalence of metabolic syndrome was higher in women than in men both before (36.4% vs. 14%) and after the community trial (26.1% vs. 16%, respectively) in the intervention areas (p < 0.001).

CONCLUSIONS

We found a significant increase in medication use to control blood pressure and dyslipidemia among the individuals with the metabolic syndrome, notably in the intervention areas. In addition to the population approach, the high-risk approach should be considered in community trials for prevention and control of non-communicable diseases.

A discovery-phase urine proteomics investigation in type 1 diabetes

Diabetes is a chronic metabolic disease which can lead to serious health problems particularly in and to the development of cardiovascular and renal complications. The aim of this study is to possibly identify distinctive molecular features in urine samples which might correlate to the progression and complications of type 1 diabetes. Diabetic patients with normo- and micro-albuminuria have been analyzed and compared to a group of control subjects. Urine proteins of control and type 1 diabetes subjects were investigated in their proteome profiles, using high-resolution two-dimensional gel electrophoresis separation and protein identifications by MALDI-TOF-MS and LC-MS/MS analysis. Proteomics analysis highlighted differential expression of several proteins between control and type 1 diabetes subjects. In particular, five proteins were found to be down-regulated and four proteins up-regulated. Lower protein representations in diabetic subjects were associated with Tamm-Horsfall urinary glycoprotein, apolipoprotein A-I, apolipoprotein E, α2-thiol proteinase inhibitor, and human complement regulatory protein CD59, while higher protein representations were found for α-1-microglobulin, zinc-α2 glycoprotein, α-1B glycoprotein, and retinol-binding protein 4. These differences were maintained comparing control subjects with type 1 diabetes normo-albuminuric and micro-albuminuric subjects. Furthermore, these proteins are correlated to glycosylated hemoglobin and microalbuminuria, confirming their role in diabetic pathology. This study gives new insights on potential molecular mechanisms associated with the complications of type 1 diabetic disease providing evidences of urine proteins potentially exploitable as putative prognostic biomarkers.

Adipocytokine zinc α2 glycoprotein (ZAG) as a novel urinary biomarker for normo-albuminuric diabetic nephropathy

OBJECTIVE

A substantial proportion of diabetic nephropathy individuals are non-albuminuric. Using a proteomic approach, we searched for novel urinary biomarkers.

METHODS

We studied three groups (n = 6 per group) of males with Type 2 diabetes: (1) normal renal function; (2) classical diabetic nephropathy (urinary albumin-creatinine ratio > 1000 mg/g and glomerular filtration rate < 60 ml/min.1.73 m(2) ) and (3) non-albuminuric diabetic nephropathy (glomerular filtration rate < 60 ml/min.1.73 m(2) and urinary albumin-creatinine ratio < 30 mg/g). We used two-dimensional fluorescence differential gel electrophoresis, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry peptide identification and western blot validation in the study.

RESULTS

Sixty protein spots were differentially abundant between the non-albuminuric and macro-albuminuric subjects (> 2.5-fold, P < 0.05). In the non-albuminuric subjects, in addition to previously reported α(1) -microglobulin, the next most interesting spot (upregulated 3.44-fold, P = 0.0026) was human zinc-α(2) -glycoprotein, a novel adipose-cytokine associated with glomerular injury. This was confirmed by western blot and replicated in female diabetic nephropathy subjects.

CONCLUSIONS

From our preliminary results, human zinc-α(2) -glycoprotein may be a novel urinary biomarker for non-albuminuric diabetic nephropathy.

Diagnosis of cardiovascular disease in patients with chronic kidney disease

The major forms of cardiovascular disease including coronary atherosclerosis, valvular disease, myocardial dysfunction, and arrhythmias are observed either alone or in combination in a large fraction of patients with chronic kidney disease (CKD). As CKD progresses, these cardiovascular conditions become more prevalent and severe. The clinical implications of combined heart and kidney disease include challenges in diagnosis and management. In addition, the terminal events in CKD commonly involve one of these four domains of cardiovascular disease. This paper will explore the issue of early diagnosis of heart disease in patients with CKD with the major goal being early intervention to lessen the impact of this comorbidity.

The metabolic syndrome is associated with complicated gallstone disease

An association between cholecystectomy and metabolic syndrome has not been fully established. Here we analyzed the association between cholecystectomy and metabolic syndrome in a Chinese population of 5672 subjects who undergone annual health checkups at the First Affiliated Hospital, College of Medicine, Zhejiang University between January 2011 and December 2012. The prevalences of gallstones, cholecystectomy and metabolic syndrome were 6.0%, 3.6%, and 32.5%, respectively. The prevalence of metabolic syndrome was significantly higher in subjects with a history of cholecystectomy (63.5%) than in those with gallstones (47.0%) or in those without gallstone disease (30.3%; P<0.01 for both). Multivariate logistic regression analysis showed that cholecystectomy was significantly associated with increased risk of metabolic syndrome (OR = 1.872; 95% CI: 1.193–2.937). However, the association of gallstones with metabolic syndrome was not statistically significant (OR = 1.267; 95% CI: 0.901–1.782). Altogether, our results suggest that cholecystectomy significantly increases the risk of metabolic syndrome.

Nonalcoholic steatohepatitis and increased risk of chronic kidney disease

Nonalcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD) share common features. Both are associated with visceral obesity, type 2 diabetes mellitus, metabolic syndrome, and insulin resistance. However, the relationship between NAFLD and CKD is poorly understood. We examined the prevalence of and risk factors for CKD in patients with NAFLD. We analyzed 174 Japanese patients with liver biopsy-proven NAFLD using a cross-sectional design. Chronic kidney disease was defined as estimated glomerular filtration rate less than 60 mL/min per 1.73 m(2) and/or overt proteinuria. Of 174 NAFLD patients, 92 (53%) exhibited histologic characteristics of nonalcoholic steatohepatitis (NASH), the progressive form of NAFLD; and 82 (47%) had non-NASH NAFLD. Chronic kidney disease was present in 24 (14%) of 174 NAFLD patients. The prevalence of CKD was significantly higher in NASH patients (19 of 92; 21%) than non-NASH patients (5 of 82; 6%). The presence of CKD was associated with a higher body mass index and the presence of hypertension and NASH. Our results demonstrated a high prevalence of CKD among patients with NASH.

Effects of fenofibrate on renal function in patients with type 2 diabetes mellitus: the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) Study

AIMS/HYPOTHESIS

Fenofibrate caused an acute, sustained plasma creatinine increase in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) and Action to Control Cardiovascular Risk in Diabetes (ACCORD) studies. We assessed fenofibrate's renal effects overall and in a FIELD washout sub-study.

METHODS

Type 2 diabetic patients (n = 9,795) aged 50 to 75 years were randomly assigned to fenofibrate (n = 4,895) or placebo (n = 4,900) for 5 years, after 6 weeks fenofibrate run-in. Albuminuria (urinary albumin/creatinine ratio measured at baseline, year 2 and close-out) and estimated GFR, measured four to six monthly according to the Modification of Diet in Renal Disease Study, were pre-specified endpoints. Plasma creatinine was re-measured 8 weeks after treatment cessation at close-out (washout sub-study, n = 661). Analysis was by intention-to-treat.

RESULTS

During fenofibrate run-in, plasma creatinine increased by 10.0 μmol/l (p < 0.001), but quickly reversed on placebo assignment. It remained higher on fenofibrate than on placebo, but the chronic rise was slower (1.62 vs 1.89 μmol/l annually, p = 0.01), with less estimated GFR loss (1.19 vs 2.03 ml min(-1) 1.73 m(-2) annually, p < 0.001). After washout, estimated GFR had fallen less from baseline on fenofibrate (1.9 ml min(-1) 1.73 m(-2), p = 0.065) than on placebo (6.9 ml min(-1) 1.73 m(-2), p < 0.001), sparing 5.0 ml min(-1) 1.73 m(-2) (95% CI 2.3-7.7, p < 0.001). Greater preservation of estimated GFR with fenofibrate was observed with baseline hypertriacylglycerolaemia (n = 169 vs 491 without) alone, or combined with low HDL-cholesterol (n = 140 vs 520 without) and reductions of ≥ 0.48 mmol/l in triacylglycerol over the active run-in period (pre-randomisation) (n = 356 vs 303 without). Fenofibrate reduced urine albumin concentrations and hence albumin/creatinine ratio by 24% vs 11% (p < 0.001; mean difference 14% [95% CI 9-18]; p < 0.001), with 14% less progression and 18% more albuminuria regression (p < 0.001) than in participants on placebo. End-stage renal event frequency was similar (n = 21 vs 26, p = 0.48).

CONCLUSIONS/INTERPRETATION

Fenofibrate reduced albuminuria and slowed estimated GFR loss over 5 years, despite initially and reversibly increasing plasma creatinine. Fenofibrate may delay albuminuria and GFR impairment in type 2 diabetes patients. Confirmatory studies are merited.

TRIAL REGISTRATION

ISRCTN64783481.

Cardiovascular disease in chronic kidney disease: data from the Kidney Early Evaluation Program (KEEP)

Diabetes mellitus (DM) and hypertension (HTN) are leading joint risk factors for both cardiovascular disease (CVD) and chronic kidney disease (CKD). In the nationwide KEEP (Kidney Early Evaluation Program) an estimated glomerular filtration rate less than 60 mL/min/1.73 m(2) or a urine albumin:creatinine ratio ≥30 mg/g (3.4 mg/mmol) defines CKD. Overall in KEEP, the rates of identified CKD and self-reported CVD are 25.7% and 22.1%, respectively. The presence of CKD has been associated with younger ages of self-reported myocardial infarction and stroke. The combination of CVD and CKD in KEEP has been associated with shorter survival time. Finally, the presence of CVD or a prior history of coronary revascularization has been associated with modestly better rates of CVD risk factor control; however, the majority of patients with CKD have suboptimally controlled blood pressure, glucose, or lipids. These data suggest that patients with CKD are not only at higher risk for CVD and subsequent mortality, but are also ideal for targeted community--and practice-based interventions to improve risk factor control and, hopefully, reduce rates of subsequent cardiovacular events.

Cardiorenal syndromes: pathophysiology to prevention

There is a strong association between both acute and chronic dysfunction of the heart and kidneys with respect to morbidity and mortality. The complex interrelationships of longitudinal changes in both organ systems have been difficult to describe and fully understand due to a lack of categorization of the common clinical scenarios where these phenomena are encountered. Thus, cardiorenal syndromes (CRSs) have been subdivided into five syndromes which represent clinical vignettes in which both the heart and the kidney are involved in bidirectional injury and dysfunction via a final common pathway of cell-to-cell death and accelerated apoptosis mediated by oxidative stress. Types 1 and 2 involve acute and chronic cardiovascular disease (CVD) scenarios leading to acute kidney injury (AKI) or accelerated chronic kidney disease (CKD). Types 3 and 4 describe AKI and CKD, respectively, leading primarily to heart failure, although it is possible that acute coronary syndromes, stroke, and arrhythmias could be CVD outcomes in these forms of CRS. Finally, CRSs type 5 describe a systemic insult to both heart and the kidneys, such as sepsis, where both organs are injured simultaneously in persons with previously normal heart and kidney function at baseline. Both blood and urine biomarkers, including the assessment of catalytic iron, a critical element to the generation of oxygen-free radicals and oxidative stress, are reviewed in this paper.

Urinary cystatin C as a potential risk marker for cardiovascular disease and chronic kidney disease in patients with obesity and metabolic syndrome

BACKGROUND AND OBJECTIVES

Obesity and metabolic syndrome (MS) increase the risk of cardiovascular disease (CVD), chronic kidney disease (CKD), and all-cause mortality. Serum cystatin C (S-CysC), a marker of GFR, has been shown to be associated with CVD and CKD. This study was designed to elucidate the association of urinary CysC (U-CysC), a marker of renal tubular dysfunction, with CVD and CKD risk factors in patients with obesity and MS.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The U-CysC-creatinine ratio (UCCR) was examined in 343 Japanese obese outpatients enrolled in the multi-centered Japan Obesity and Metabolic Syndrome Study.

RESULTS

UCCR was positively correlated with urine albumin-creatinine ratio (UACR) and S-CysC and negatively correlated with estimated GFR (eGFR). Among obese patients, UCCR was significantly higher in MS patients than in non-MS patients. UCCR had significant correlations with the number of components of MS and arterial stiffness, all of which are CVD predictors, similarly to UACR (P<0.05). Interestingly, diet- and exercise-induced weight reduction for 3 months significantly decreased only UCCR among all of the renal markers examined (P<0.01), in parallel with the decrease in BMI, HbA1c, and arterial stiffness, suggesting the beneficial effect of weight reduction on renal tubular dysfunction.

CONCLUSIONS

This study demonstrates that UCCR is significantly associated with renal dysfunction, the severity of MS, arterial stiffness, and weight change in obese patients. The data of this study suggest that U-CysC could serve as a CVD and CKD risk factor in patients with obesity and MS.

Long-term high intake of whole proteins results in renal damage in pigs

Despite evidence of potential antiobesity effects of high-protein (HP) diets, the impact of consuming diets with protein levels at the upper limit of the acceptable macronutrient distribution range (AMDR) on kidney health is unknown. To test whether HP diets affect renal health, whole plant and animal proteins in proportions that mimicked human diets were given to pigs, because their kidneys have a similar anatomy and function to those of humans. Adult female pigs received either normal-protein (NP) or HP (15 or 35% of energy from protein, respectively) isocaloric diets for either 4 or 8 mo. The higher protein in the HP diet was achieved by increasing egg and dairy proteins. Although there were initial differences in body weight and composition, after 8 mo these were similar in pigs consuming the NP and HP diets. The HP compared with NP diet, however, resulted in enlarged kidneys at both 4 and 8 mo. Renal and glomerular volumes were 60-70% higher by the end of the study. These enlarged kidneys had greater evidence of histological damage, with 55% more fibrosis and 30% more glomerulosclerosis. Renal monocyte chemoattractant protein-1 levels also were 22% higher in pigs given the HP diet. Plasma homocysteine levels were higher in the HP pigs at 4 mo and continued to be elevated by 35% at 8 mo of feeding. These findings suggest that long-term intakes of protein at the upper limit of the AMDR from whole protein sources may compromise renal health.