Cristiane Moraes

Resistance exercise training does not affect plasma irisin levels of hemodialysis patients.

Irisin, a hormone secreted by myocytes induced in exercise, acts as a muscle-derived energy-expenditure signal that binds to undetermined receptors on the white adipose tissue surface, stimulating its browning and uncoupling protein 1 (UCP1) expression. The purpose of this study was to assess the effect of an intradialytic resistance exercise training program (RETP) on plasma irisin levels of hemodialysis (HD) patients and compare the baseline plasma irisin levels of HD patients to healthy subjects. This longitudinal study enrolled 26 patients undergoing HD (50% men, 44.8±14.1 years, body mass index (BMI) 23.5±3.9 kg/m²). The healthy subjects group consisted of 11 women and 7 men with mean age of 50.9±6.6 years and BMI, 24.2±2.7 kg/m². Anthropometric and biochemistry parameters (Irisin by Enzyme-Linked Immunosorbent Assay) were measured at the baseline and after 6 months of RETP (in both lower limbs). There was no difference regarding gender, age, and BMI between HD patients and healthy subjects. Plasma irisin levels in HD patients were lower than in healthy subjects (71.0±41.6 vs. 101.3±12.5 ng/ml, p<0.05). Although the muscle mass increased in consequence of exercise [evaluated by arm muscle area from 27.9 (24.1) to 33.1 (19.0) cm²], plasma irisin did not differ significantly after exercises (71.0±41.6 vs. 73.3±36.0 ng/ml). HD patients seem to have lower plasma irisin when compared to healthy subjects. Moreover, a resistance exercise training program was unable to augment plasma irisin despite increasing muscle mass.

Is a body mass index of 23 kg/m2 a reliable marker of protein–energy wasting in hemodialysis patients?

OBJECTIVE To evaluate the body composition and inflammatory status in patients on hemodialysis (HD) according to the cutoff of 23 kg/m² for the body mass index (BMI). METHODS Forty-seven patients (30 men, 11 diabetics, 53.8 ± 12.2 y of age, 58.2 ± 50.9 mo on HD) were studied. Anthropometric data and handgrip strength were evaluated. C-reactive protein, tumor necrosis factor-α, leptin, and interleukin-6 were measured. Mortality was assessed after 24 mo of follow-up. RESULTS Nineteen patients (40.4%) presented BMI values lower than 23 kg/m² and leptin levels, midarm muscle area, and free-fat mass were significantly lower in these patients. The prevalence of functional muscle loss according to handgrip strength was not different between the BMI groups. The sum of skinfold thicknesses, the percentage of body fat, fat mass, the fat mass/free-fat mass ratio, and waist circumference were significantly lower in patients with a BMI lower than 23 kg/m², but the mean values did not indicate energy wasting. Patients with a BMI higher than 23 kg/m² presented a higher prevalence of inflammation and higher waist circumference and body fat values. The adiposity parameters were correlated with C-reactive protein and leptin. A Cox multivariate regression analysis demonstrated that C-reactive protein, tumor necrosis factor-α, and interleukin-6 predict cardiovascular mortality. CONCLUSION Patients on HD with a BMI lower than 23 kg/m² did not present signs of energy wasting, whereas those with a BMI higher than 23 kg/m² had more inflammation, probably because of a greater adiposity. Thus, the BMI value of 23 kg/m² does not seem to be a reliable marker of protein-energy wasting in patients on HD.

Underreporting of Energy Intake in Maintenance Hemodialysis Patients: A Cross-sectional Study

OBJECTIVE To analyze the reported energy intake (EI(rep)) in hemodialysis (HD) patients by total energy expenditure (TEE) measured by a dedicated device. DESIGN Cross-sectional study. SETTING RenalCor and RenalVida Clinics (Rio de Janeiro, Brazil). PATIENTS AND OTHERS PARTICIPANTS Forty-eight HD patients (51.4 ± 12.2 years, 62% men, body mass index [BMI], 23.8 ± 4.5 kg/m(2)) were studied. MAIN OUTCOME MEASURE EI(rep) was evaluated using a 3-day food record. TEE was measured over a 2-day period by SWA (SenseWear Pro2 Armband, BodyMedia Inc., Pittsburgh, PA). Subjects were identified as underreporters (URs), acceptable reporters (ARs), or overreporters (ORs) from their EI(rep)/TEE ratio. ARs were defined as having the EI(rep)/TEE ratio in the range of 0.76 to 1.24, URs as EI(rep)/TEE <0.76, ORs as EI(rep)/TEE >1.24 according to Goldberg index. RESULTS The mean TEE and EI(rep) were 34.7 ± 9.4 kcal/kg/day and 22.8 ± 10.6 kcal/kg/day, respectively, and 37.5% of patients presented overweight or obesity. Thirty-one patients (65%) were identified as URs, and the mean of Goldberg index was 0.54 ± 0.12 (0.23 to 0.75), versus 0.95 ± 0.12 (0.79 to 1.2) for ARs. There were no ORs among the patients studied. There were negative correlations between Goldberg index and BMI (r = -0.35, P < .01) and % body fat (r = -0.4, P < .01) and between EI(rep) and BMI (r = -0.58, P < .001). CONCLUSION These results confirm a high prevalence of underreporting of EI in HD patients, particularly in patients with high BMI.

Trimethylamine N-Oxide From Gut Microbiota in Chronic Kidney Disease Patients: Focus on Diet

Low-protein diet is the recommended nutritional intervention for nondialysis chronic kidney disease (CKD) patients because excess protein intake can damage kidney function and produce uremic toxins. Some of these toxins are generated from amino acids breakdown by gut microbiota as p-cresyl sulfate and indoxyl sulfate that have been clearly associated with cardiovascular mortality in CKD patients. Another uremic toxin, trimethylamine N-oxide (TMAO), a degradation product of choline and L-carnitine (which come mainly from animal protein such as red meat and eggs) is now considered as a proatherogenic metabolite. In the present review, we will highlight the relationship between TMAO, diet and cardiovascular aspects, and the potential concerns about TMAO in nondialysis CKD patients.

Effect of Brazil Nut Supplementation on Plasma Levels of Selenium in Hemodialysis Patients: 12 Months of Follow-up

BACKGROUND Large amounts of reactive oxygen species are produced in hemodialysis (HD) patients, and, at higher concentrations, reactive oxygen species are thought to be involved in the pathogenesis of cardiovascular disease. It has been proposed that selenium (Se) may exert an antiatherogenic influence by reducing oxidative stress. The richest known food source of Se is the Brazil nut (Bertholletia excelsa, family Lecythidaceae), found in the Amazon region. OBJECTIVE The objective of this work was to determine if Se plasma levels in HD patients submitted to a program of supplementation during 3 months with 1 Brazil nut by day could be sustained after 12 months. METHODS A total of 21 HD patients (54.2 ± 15.2 years old; average time on dialysis, 82.3 ± 51.6 months; body mass index, 24.4 ± 3.8 kg/m(2)) from the RenalCor Clinic in Rio de Janeiro, Brazil, were followed up 12 months after the supplementation study ended. The Se plasma levels were determined by atomic absorption spectrophotometry with hydride generation. RESULTS The Se Plasma levels (17.3 ± 19.9 μg/L) were below the normal range (60 to 120 μg/L) before nut supplementation, and after 3 months of supplementation, the levels increased to 106.8 ± 50.3 μg/L (P < .0001). Twelve months after supplementation, the plasma Se levels decreased to 31.9 ± 14.8 μg/L (P < .0001). CONCLUSIONS The data showed that these patients were Se deficient and that the consumption of Brazil nut was effective to increase the Se parameters of nutritional status. Se levels 12 months after the supplementation period were not as low as presupplementation levels but yet significantly lower, and we needed to motivate patients to adopt different dietary intake patterns.

Construção, adaptação e validação de escalas de silhuetas para autoavaliação do estado nutricional: uma revisão sistemática da literatura

Self-assessment of body image is a multidimensional construction by which individuals describe the internal representations of their body structure and physical appearance in relation to themselves and others. Silhouette scales have been used to for self-assessment of nutritional status, due to their low cost and ease of administration, especially in field surveys. This study aimed to identify the various silhouette scales that have been developed or adapted since 1983 and to conduct a systematic review of the validation of such scales against objective measures of nutritional status. A total of 33 publications were found and showed moderate to good correlation between nutritional status and both adapted (0.66 to 0.87) and developed silhouette scales (0.59 to 0.94) in adults, but much lower correlation in children and adolescents. Most of the studies used inappropriate statistical analysis. The data indicated that silhouette scales should be used with caution to predict nutritional status with or without anthropometric measures.

Resistant starch for modulation of gut microbiota: Promising adjuvant therapy for chronic kidney disease patients?

The gut microbiota has been extensively studied in all health science fields because its imbalance is linked to many disorders, such as inflammation and oxidative stress, thereby contributing to cardiovascular disease, obesity, diabetes and chronic kidney disease (CKD) complications. Novel therapeutic strategies that aim to reduce the complications caused by this imbalance have increased in recent years. Studies have shown that prebiotic supplementation can beneficially modulate the gut microbiota in CKD patients. Prebiotics consist of non-digestible dietary soluble fiber, which acts as a substrate for the gut microbiota. Resistant starch (RS) is a type of dietary fiber that can reach the large bowel and act as a substrate for microbial fermentation; for these reasons, it has been considered to be a prebiotic. Few studies have analyzed the effects of RS on the gut microbiota in CKD patients. This review discusses recent information about RS and the potential role of the gut microbiota, with a particular emphasis on CKD patients.

Is there association between acyl-ghrelin and inflammation in hemodialysis patients?

INTRODUCTION AND OBJECTIVES Patients with chronic kidney disease (CKD) present anorexia, which may be related with the chronic inflammatory process. Thus the objective of this study was to evaluate if there is association between inflammation and the orexigenic hormone, acyl-ghrelin, in CKD patients undergoing hemodialysis (HD). METHODS Thirty-six patients were studied (61.1% men, 46.7 ± 14.9 years, BMI 22.9 ± 3.9 kg/m²) in regular HD program (65.0 ± 46.8 months). Plasma levels of acyl-ghrelin and inflammatory markers TNF-α, IL-6 and CRP were measured by enzyme immunoassay (ELI-SA, Enzyme Linked Immunosorbent Assay). Anthropometric parameters were collected for assessment of nutritional status and dietary intake was assessed by food recall. RESULTS The patients presented elevated plasma levels of IL-6 (83 ± 10 pg/mL), TNF-α (21.06 pg/mL [20.6-40.0]) and CRP (2.7 pg/mL [1.73.4]) compared to normal values. Acylghrelin plasma levels were (18.0 [1.3 to 77.7 pg/mL]) low when compared to healthy individuals. However, patients with high BMI (> 25 kg/m²) presented lower acyl-ghrelin plasma levels (13.6 [1.3 to 30.5] pg/mL) when compared to patients with BMI < 25 kg/m² (21.7 [7.4 to 77.7] pg/mL) (p < 0.05). Acylghrelin and BMI were negatively correlated (r = -0.38, p = 0.02) and there was no significant correlation between acyl-ghrelin and inflammatory markers. CONCLUSIONS Hemodialysis patients showed low acyl-ghrelin levels and seem to present an acyl-ghrelin resistance and there was no correlation between inflammation and this orexigenic hormone.

Red meat intake in chronic kidney disease patients: Two sides of the coin

Red meat is an important dietary source of high biological value protein and micronutrients such as vitamins, iron, and zinc that exert many beneficial functions. However, high consumption of animal protein sources, especially red meat, results in an increased intake of saturated fat, cholesterol, iron, and salt, as well as an excessive acid load. Red meat intake may lead to an elevated production of uremic toxins by the gut microbiota, such as trimethylamine n-oxide (TMAO), indoxyl sulfate, and p-cresyl sulfate. These uremic toxins are associated with increased risk for cardiovascular (CV) mortality. Limiting the intake of red meat in patients with chronic kidney disease (CKD) thus may be a good strategy to reduce CV risk, and may slow the progression of kidney disease. In the present review, we discuss the role of red meat in the diet of patients with CKD. Additionally, we report on a pilot study that focused on the effect of a low-protein diet on TMAO plasma levels in nondialysis CKD patients.

Linking Zinc and Leptin in Chronic Kidney Disease: Future Directions

Anorexia is a common complication in patients with chronic kidney disease (CKD) and is associated with the development of malnutrition and an increased risk of mortality. Several compounds are linked to anorexia in these patients; however, the mechanisms are unknown. Zinc (Zn) deficiency is associated with decreased food intake and has been observed in CKD patients. In addition, leptin is an anorexigenic peptide, and patients with CKD present generally high levels of this hormone. Studies have suggested an association between Zn and leptin status in human and rats; however, the results are inconsistent. Some claimed that Zn supplementation does not change leptin release or that there is no significant relationship between Zn and leptin. Others have reported that Zn might be a mediator of leptin production. CKD patients have hyperleptinemia and hypozincemia, but the relationship between Zn deficiency and leptin levels in CKD patients has been poorly understood until now. The aim of this review is to integrate knowledge on leptin and Zn actions to provide a cohesive clinical perspective regarding their interactions in CKD patients.