Annual variation in body fat is associated with systemic inflammation in chronic kidney disease patients Stages 3 and 4: a longitudinal study

The role of exercise in improving hyperlipidemia-renal injuries induced by a high-fat diet: a literature review

A diet that is high in sugar and fat is a precursor to various chronic diseases, especially hyperlipidemia. Patients with hyperlipidemia have increased levels of plasma free fatty acids and an ectopic accumulation of lipids. The kidney is one of the main organs affected by this disease and, recently, there have been more studies conducted on renal injury caused by hyperlipidemia. The main pathological mechanism is closely related to renal lipotoxicity. However, in different kidney cells, the reaction mechanism varies due to the different affinities of the lipid receptors. At present, it is believed that in addition to lipotoxicity, hyperlipidemia induced-renal injury is also closely related to oxidative stress, endoplasmic reticulum stress, and inflammatory reactions, which are the result of multiple factors. Exercise plays an important role in the prevention of various chronic diseases and recently emerging researches indicated its positive effects to renal injury caused by hyperlipidemia. However, there are few studies summarizing the effects of exercise on this disease and the specific mechanisms need to be further explored. This article summarizes the mechanisms of hyperlipidemia induced-renal injury at the cellular level and discusses the ways in which exercise may regulate it. The results provide theoretical support and novel approaches for identifying the intervention target to treat hyperlipidemia induced-renal injury.

C-reactive protein levels are associated with periodontitis and periodontal inflamed surface area in adults with end-stage renal disease

BACKGROUND

Several studies have shown the relationship between periodontal disease and chronic kidney disease, but there is little evidence to assess the impact of the amount of inflamed periodontal tissue on the levels of systemic inflammatory markers. So the aim of this study is determine the association between high-sensitivity C-reactive protein (hsCRP) and both periodontitis and periodontal inflamed surface area (PISA) in adults with end-stage renal disease (ESRD).

METHODS

Cross-sectional study was conducted with 176 adults with ESRD on regular hemodialysis. The participants were submitted to a full-mouth periodontal examination to determine the occurrence of periodontitis and PISA. Regression analysis was performed to test the independent association between periodontal conditions and serum hsCRP levels.

RESULTS

A total of 98.9% of the participants had periodontitis, with stages III and IV found in 26.1% and 52.9%, respectively. Mean hsCRP and PISA was 6.57 (SD: 6.03) mg/L and 217.15 (SD: 271.50), respectively. In the adjusted analysis, mean serum hsCRP levels were significantly higher in patients with stage III and IV generalized periodontitis compared with no/localized/generalized stages I-II (7.67 mg/L versus 5.72 mg/L, P = 0.028). After adjustments for confounding variables, individuals with PISA >490.56 mm² (85th percentile) had a 3.26-fold greater chance of having hsCRP above 5 mg/L than their counterparts (OR = 3.26; 95% CI: 1.25 to 8.49).

CONCLUSION

The inflammatory burden imposed by periodontitis can increase serum hsCRP levels in adults with end-stage renal disease.

Effects of Diet Intervention on Body Composition in the Elderly with Chronic Kidney Disease

Objective: It has been uncertain that low protein diet for patients with chronic kidney disease (CKD) may predispose to malnutrition. The study aimed to investigate the effects of low protein diet on body composition of CKD patients and analyze the influence of age. Methods: Patients with glomerular filtration rate less than 45 mL/min/1.73m² including 103 elderly (70.7 ± 6.9 years old) and 56 non-elderly (49.8 ± 9.1 years old) CKD patients were enrolled. All patients were educated by dietitians to take low protein diet and were followed up regularly every three months. Their demographic data, underlying disease and body mass index (BMI) were reviewed and recorded. Results of body composition measurement and laboratory tests were collected every three months for one year. Results: At baseline, the distribution of body composition was similar in non-elderly patients between non-low and low protein groups. In the elderly, patients in low protein group had higher fat and lower muscle percentage. In one-year follow-up, non-elderly patients did not present significant changes in their BMI, serum albumin level and body compositions in both protein groups. Non-low protein group in elderly patients had significant decrease in BMI and estimated glomerular filtration rate (eGFR) after 12 months (both p< 0.05). Determination in body composition showed decrease in fat and increase in muscle component. In low protein group, their BMI was decreased and eGFR was not influenced. Fat component was decreased and muscle percentage was increased in one-year follow-up. Conclusions: In elderly CKD patients, low protein diet maintained good nutritional status and muscle mass was preserved.

Controversial issues in CKD clinical practice: position statement of the CKD-treatment working group of the Italian Society of Nephrology

This position paper of the study group "Conservative treatment of Chronic Kidney Disease-CKD" of the Italian Society of Nephrology addresses major practical, unresolved, issues related to the conservative treatment of chronic renal disease. Specifically, controversial topics from everyday clinical nephrology practice which cannot find a clear, definitive answer in the current literature or in nephrology guidelines are discussed. The paper reports the point of view of the study group. Concise and practical advice is given on several common issues: renal biopsy in diabetes; dual blockade of the renin-angiotensin-aldosterone system (RAAS); management of iron deficiency; low protein diet; dietary salt intake; bicarbonate supplementation; treatment of obesity; the choice of conservative therapy vs. dialysis. For each topic synthetic statements, guideline-style, are reported.

Fat tissue and inflammation in patients undergoing peritoneal dialysis

Background

Body weight has been increasing in the general population and is an established risk factor for hypertension, diabetes, and all-cause and cardiovascular mortality. Patients undergoing peritoneal dialysis (PD) gain weight, mainly during the first months of treatment. The aim of this study was to assess the relationship between body composition and metabolic and inflammatory status in patients undergoing PD.

Methods

This was a prospective, non-interventional study of prevalent patients receiving PD. Body composition was studied every 3 months using bioelectrical impedance (BCM^®). We performed linear regression for each patient, including all BCM^® measurements, to calculate annual changes in body composition. Thirty-one patients in our PD unit met the inclusion criteria.

Results

Median follow-up was 26 (range 17–27) months. Mean increase in weight was 1.8 ± 2.8 kg/year. However, BCM^® analysis revealed a mean increase in fat mass of 3.0 ± 3.2 kg/year with a loss of lean mass of 2.3 ± 4.1 kg/year during follow-up. The increase in fat mass was associated with the conicity index, suggesting that increases in fat mass are based mainly on abdominal adipose tissue. Changes in fat mass were directly associated with inflammation parameters such as C-reactive protein (r = 0.382, P = 0.045) and inversely associated with high-density lipoprotein cholesterol (r=−0.50, P = 0.008).

Conclusions

Follow-up of weight and body mass index can underestimate the fat mass increase and miss lean mass loss. The increase in fat mass is associated with proinflammatory state and alteration in lipid profile.

Serum C-reactive protein levels in pre-dialysis chronic kidney disease patientsin southern Nigeria

BACKGROUND

Cardiovascular disease is the major cause of hospitalization and mortality in chronic kidney disease (CKD). C-reactive protein (CRP) is a marker of cardiovascular disease and predictor of mortality in CKD patients. CKD patients with elevated CRP should be identified early with institution of measures to treat cardiovascular risk factors in order to reduce attendant mortality.

AIMS

Determination of serum CRP levels in CKD patients and associated factors.

METHODS

This was a case-control study involving 80 consecutive CKD patients and 40 control subjects without CKD. Data obtained from participants included demographics, body mass index (BMI), and aetiology of CKD. Serum CRP levels, albumin, creatinine and lipid profile were determined. Cases and controls were compared. P values <0.05 were taken as significant.

RESULTS

The mean age of the CKD subjects was 49.09±16.85 years. The median CRP value was significantly higher in the CKD group compared to controls (p=<0.001). Low, average and high cardiovascular event risk according to CRP values were present in 51(63.8%), 13(16.2%) and 16(20%) of the CKD patients respectively. Cardiovascular event risk was significantly higher in CKD subjects (p=<0.001). Serum creatinine, BMI, triglyceride and atherogenic index of plasma correlated positively with CRP. Estimated glomerular filtration rate (eGFR), high density lipoprotein-cholesterol and albumin correlated negatively with CRP. Elevated serum CRP was significantly predicted by low eGFR and high BMI on multivariate analysis.

CONCLUSION

Chronic kidney disease patients have increased cardiovascular event risk. Interventions aimed at reducing weight and treating dyslipidaemia should be instituted early in order to reduce this risk.

Epicardial fat accumulation, cardiometabolic profile and cardiovascular events in patients with stages 3-5 chronic kidney disease

BACKGROUND

It has been hypothesized that epicardial adipose tissue (EAT) exerts pathogenic effects on cardiac structures. We analysed the associations between EAT and both cardiovascular (CV) disease risk factors and CV events in patients with chronic kidney disease (CKD).

PATIENTS AND METHODS

We included 277 nondialysed patients [median age 61, interquartile range (IQR) 53-68 years; 63% men] with stages 3-5 CKD in this cross-sectional evaluation. EAT and abdominal visceral adipose tissue (VAT) were assessed by computed tomography. Patients were followed for median 32 (IQR 20-39) months, and the composite of fatal and nonfatal CV events was recorded.

RESULTS

With increasing EAT quartiles, patients were older, had higher glomerular filtration rate, body mass index, waist, VAT and coronary calcification, higher levels of haemoglobin, triglycerides, albumin, C-reactive protein and leptin and higher prevalence of left ventricular hypertrophy and myocardial ischaemia; total and high-density lipoprotein cholesterol, 25-hydroxy-vitamin D and 1, 25-dihydroxy-vitamin D progressively decreased. Associations between EAT and cardiac alterations were not independent of VAT. During follow-up, 58 CV events occurred. A 1-SD higher EAT volume was associated with an increased risk of CV events in crude [hazard ratio (HR) 1.41, 95% confidence interval (CI) (1.12-1.78) and adjusted (HR 1.55, 95% CI 1.21-1.99) Cox models. However, adding EAT to a standard CV disease risk prediction model did not result in a clinically relevant improvement in prediction.

CONCLUSION

Epicardial adipose tissue accumulation in patients with CKD increases the risk of CV events independent of general adiposity. This is consistent with the notion of a local pathogenic effect of EAT on the heart or heart vessels, or both. However, EAT adds negligible explanatory power to standard CV disease risk factors.

Lower plasma sodium is associated with a microinflammatory state among patients with advanced chronic kidney disease

BACKGROUND/AIMS

Lower serum sodium levels have been associated with increased mortality among patients with chronic kidney disease (CKD). Our aim was to analyze the independent factors associated with lower sodium levels among nondialysis patients with advanced CKD and to evaluate the evolution of these patients in comparison to those with higher plasma sodium over a 1-year period.

METHODS

We included 72 patients with CKD stages 4 and 5 without clinically evident cardiopathy or liver disease. Bioelectrical impedance and echocardiography were performed to analyze the possible relation between plasma sodium and volume status and subclinical left ventricular (LV) dysfunction. During follow-up, we compared the evolution of patients with lower baseline plasma sodium (low quartile: <138 mEq/l) with that of patients with higher levels over a 1-year period.

RESULTS

At baseline, the independent predictors of lower plasma sodium were C-reactive protein (CRP; OR 0.96; 95% CI 0.91-0.99) and body mass index (OR 0.89; 95% CI 0.78-0.99). An inverse correlation between plasma sodium and CRP was observed (r = -0.32; p = 0.01). Plasma sodium did not correlate with extracellular water and was not different between patients with or without echocardiographic data of LV dysfunction (p = 0.7). During follow-up, patients with lower sodium at baseline showed persistently lower sodium values (p = 0.04), higher CRP (p = 0.05), lower serum albumin (p < 0.01) and higher erythropoietin-stimulating agent resistance index (p = 0.05).

CONCLUSIONS

Our results suggest an association between lower plasma sodium and a microinflammatory state among patients with advanced CKD. Inflammation could be an underlying confounding factor explaining the increased mortality in these patients.

Visceral adiposity index and risks of cardiovascular events and mortality in prevalent hemodialysis patients

Background

The visceral adiposity index (VAI) is a newly-derived measure of visceral adiposity with well-validated predictive power for cardiovascular (CV) outcomes in the general population. However, this predictability has not been investigated in hemodialysis patients, and whether VAI is superior to waist circumference (WC) and waist-to-height ratio (WHtR) in predicting CV outcomes and survival in hemodialysis patients remains unknown.

Methods

We performed a prospective study including 464 prevalent hemodialysis patients. The composite outcome was the occurrence of death and CV events during follow-up. Using multivariate Cox regression analysis, VAI, WC and WHtR were tested for the predictive power of outcomes. To evaluate the predictive performance of the VAI, WC and WHtR, time-dependent receiver operating characteristic curve (ROC) analysis was performed.

Results

VAI, WC and WHtR positively correlated with each other. Patients with a higher VAI (tertile 3 vs. tertile 1, adjusted hazard ratio (HR), 1.65; 95% confidence interval (CI), 1.12-2.42; tertile 2 vs. tertile 1, adjusted HR, 1.52; 95% CI, 1.1-2.18) had more composite outcomes. VAI had a similar predictive power of all-cause mortality to WC and WHtR, but superior predictive power of composite and CV outcomes to WC when analyzed by a stepwise forward likelihood ratio test. In time-dependent ROC analysis, VAI, WC and WHtR showed similar predictive performance for outcomes.

Conclusion

VAI is an optimal method to measure visceral adiposity to assess long-term CV outcomes and all-cause mortality in prevalent hemodialysis patients. VAI may provide a superior predictive power of CV outcomes to WC and WHtR.

Trial registration

ClinicalTrials.gov NCT01457625

Inflammatory stress reduces the effectiveness of statins in the kidney by disrupting HMGCoA reductase feedback regulation

BACKGROUND

Patients with chronic kidney disease (CKD) are unlikely to gain the same benefit from conventional doses of statins as do patients with cardiovascular disease alone. This study investigated whether inflammation accompanying CKD causes statin resistance.

METHODS

Inflammatory stress was induced by adding cytokines and lipopolysaccharide (LPS) to human mesangial cells (HMCs) in vitro, and in vivo by subcutaneous casein injection in apolipoprotein E, scavenger receptors class A and CD36 triple knockout mice.

RESULTS

Inflammatory stress exacerbated cholesterol accumulation and was accompanied in vitro and in vivo by increased HMGCoA reductase (HMGCoA-R) mRNA and protein expression mediated via activation of the sterol regulatory element-binding protein cleavage-activating protein (SCAP)/sterol regulatory element-binding protein 2 pathway. Atorvastatin reduced HMGCoA-R enzymatic activity and intracellular cholesterol synthesis in vitro; however, inflammatory stress weakened these suppressive effects. Atorvastatin at concentrations of 15 µM inhibited HMGCoA-R activity by 50% (IC50) in HMCs, but the same concentration in the presence of interleukin (IL)-1β resulted in only 30% inhibition of HMGCoA-R activity in HMCs. Knocking down SCAP prevented statin resistance induced by IL-1β, and overexpression of SCAP-induced statin resistance even without inflammatory stress. In vivo, the amount of atorvastatin required to lower serum cholesterol and decrease kidney lipid accumulation rose from 2 to 10 mg/kg/day in the presence of inflammatory stress.

CONCLUSIONS

Inflammatory stress can disrupt HMGCoA-R-mediated cholesterol synthesis resulting in intracellular lipid accumulation and statin resistance.

Association of body fat with inflammation in peritoneal dialysis

Peritoneal dialysis (PD) frequently leads to body weight gain, which appears to be a potential cause of the chronic inflammation frequently present in these patients. The consequences of this inflammation are impaired nutritional status, accelerated atherosclerosis, and increased mortality. To assess the association between inflammation and body fat in female patients treated with PD. Nineteen female patients on PD for at least 6 months with no infectious complications or malignant or acute inflammatory diseases. Nutritional status was determined by measuring weight, height, body mass index (BMI), waist (WC), and mid-arm circumferences (MAC), mid-arm muscle area, and tricipital fold (TCF). Bioelectrical impedance (BIA) was used to determine body composition. Biochemical evaluation included the determination of serum albumin, urea, creatinine, and C-reactive protein (CRP). The glucose absorbed from the dialysis solution was quantitated. According to BMI, two patients were classified as malnourished and ten as overweight/obese. Sixteen individuals had high WC measurements and 12 had excess body fat (BF) as measured by BIA. High CRP levels were observed in 12 patients, who had higher WC, MAC, BMI, TCF, and BF measurements compared to non-inflamed patients. Positive associations were detected between CRP and BMI, MAC, WC, and TCF. Associations between BF and CRP suggest that adiposity may be a potent exacerbating factor of inflammation in this population, especially visceral fat. Thus, obesity may be considered to be one more factor responsible for the early atherosclerosis and high cardiovascular mortality observed in these patients.

Relationship between changes in body fat and a decline of renal function in the elderly

Obesity is a risk factor for chronic kidney disease, and its prevalence among the elderly is increasing. We investigated the effects of changes in body fat percentage (BFP) on the longitudinal changes in the estimated glomerular filtration rate (eGFR) in the elderly. This prospective cohort study included 390 participants aged >65 years who underwent bioelectrical impedance analysis at baseline and follow-up as a part of the Korean Longitudinal Study on Health and Aging. After a median follow-up period of 5.3 years, BFP was significantly higher than that at the start point (P<0.05). Participants who had the largest increase in BFP had the highest BMI and waist circumference (WC) (P<0.001). The highest tertile had the highest white blood cell count and erythrocyte sedimentation rate, incidence of rapid progression, and decline in eGFR >25% (P≤0.017, P = 0.025, P = 0.005, respectively). The lowest tertile had the lowest triglyceride and highest high-density lipoprotein levels (P<0.05). The adjusted decline rate in eGFR was correlated with a change in BFP (P = 0.039), but not with that in BMI or WC. The highest tertile had a 4.875-fold increase in the risk for rapid progression to a decline in eGFR (95% CI: 1.366-17.397) and a 4.931-fold decrease in the risk to a decline in eGFR>25% (95% CI: 1.617-15.037), when compared with the lowest tertile. In subgroup analysis, the incidence of renal outcomes was significantly increased according to the increase in BFP in patients with lower eGFR (P≤0.010). A change in BFP may be associated with inflammation and dyslipidemia development, and longitudinal changes in body fat are related to a decrease in eGFR in the elderly.

Adiposity and cardiovascular disease risk factors in renal transplant recipients: Are there differences between sexes?

OBJECTIVE

The aim of this study was to evaluate high body adiposity and cardiovascular disease (CVD) risk factors prevalence, in renal transplant recipients (RTR), comparing men with women.

METHODS

In this retrospective cross-sectional study, 102 patients (55 men) who were 49 ± 1.2 y and 114.3 ± 9 mo post-transplant (post-tx) were evaluated. Pretransplant (pre-tx) period data and weight gain during the first year post-tx were obtained from patient charts and post-tx data were collected during a routine visit at nephrology clinic. Body mass index (BMI) ≥ 25 kg/m(2) defined overweight and BMI ≥ 30 kg/m(2) defined obesity.

RESULTS

Pre-tx overweight prevalence was low and similar between men and women (26%), whereas only women showed obesity (11%). Post-tx body weight increased significantly in the entire group, leading to an increase in overweight (to 38% in men and 51% in women) and obesity (to 11% in men and 23% in women) prevalence. Post-tx comparisons between men and women showed that women had higher (women versus men; P < 0.05) BMI values (26.7 ± 0.8 versus 24.7 ± 0.5 kg/m(2)), weight gain during first year post-tx (9.2 ± 1.1 versus 5.5 ± 1 kg), abdominal obesity (57% versus 23%) and diabetes (34% versus 16%) prevalence. The associations between adiposity and CVD risk factors showed that pre-tx overweight increased the risk for diabetes in post-tx; pos-tx high BMI and abdominal obesity increased the risk for metabolic syndrome; abdominal obesity increased the risk for dyslipidemia in women.

CONCLUSIONS

High body adiposity prevalence was high after transplantation and increased the risk for metabolic syndrome, an important CVD risk factor. Women showed higher total body adiposity values, abdominal obesity, and diabetes prevalence than men. Abdominal obesity increased the risk for dyslipidemia in women.

Can renal nutrition education improve adherence to a low-protein diet in patients with stages 3 to 5 chronic kidney disease?

OBJECTIVE

Low adherence is frequently observed in patients with chronic kidney disease (CKD) who are following a low-protein diet. We have evaluated whether a specific nutrition education program motivates patients with CKD who do not yet receive dialysis to reduce their protein intake and whether such a program improves adherence to a low-protein diet over and above standard dietary counseling.

DESIGN AND METHODS

This was a randomized controlled clinical trial conducted at the CKD outpatient clinic at Pedro Ernesto University Hospital, Rio de Janeiro, Brazil.

SUBJECTS

This study included adult patients with an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2) who were receiving conservative treatment. Participants had received their first referrals to a renal dietitian.

INTERVENTION

Patients were randomized to a normal counseling group (individualized dietary program: 0.6 to 0.75 g protein/kg/day or 0.6 to 0.8 g/kg/day for patients with diabetes and 25 to 35 kcal/kg/day with sodium restriction) or an intense counseling group (same dietary program plus nutrition education materials). The nutrition education material included 4 different actions to improve patient knowledge and understanding of the low-protein and low-sodium diet. Both groups were followed by means of individual monthly visits to the outpatient clinic for 4 months.

MAIN OUTCOME MEASURE

We looked for a change in protein intake from baseline values as well as the adherence rate, assessed as a 20% decrease of the initial protein intake (by 24-hour food recall).

RESULTS

Eighty-nine patients completed the study (normal counseling n = 46; intense counseling n = 43). The number of patients who adhered to a low-protein diet was high but did not differ between groups (in the last visit 69% vs. 48%; P = .48; intense vs. normal counseling, respectively). The reduction in protein intake from baseline values was greater for the intense counseling group compared with the normal counseling group (at the last visit, -20.7 g/day [-30.9%] vs. -10.5 g/day [-15.1%], intense vs. normal counseling, respectively; P = .04).

CONCLUSION

An intense nutrition education program contributed to reducing protein intake in patients with stage 3 to 5 CKD over and above our standard dietary counseling. Nutritional education programs are effective in increasing patient adherence to protein intake recommendations.