Association between the relative abundance of phyla actinobacteria, vitamin C consumption, and DNA methylation of genes linked to immune response pathways.

Introduction: There is an emerging body of evidence that vitamin C consumption can modulate microbiota abundance and can also impact DNA methylation in the host, and this could be a link between diet, microbiota, and immune response. The objective of this study was to evaluate common CpG sites associated with both vitamin C and microbiota phyla abundance. Methods: Six healthy women participated in this cohort study. They were divided into two groups, according to the amount of vitamin C they ingested. Ingestion was evaluated using the 24-h recall method. The Illumina 450 k BeadChip was used to evaluate DNA methylation. Singular value decomposition analyses were used to evaluate the principal components of this dataset. Associations were evaluated using the differentially methylated position function from the Champ package for R Studio. Results and discussion: The group with higher vitamin C (HVC) ingestion also had a higher relative abundance of Actinobacteria. There was a positive correlation between those variables (r = 0.84, p = 0.01). The HVC group also had higher granulocytes, and regarding DNA methylation, there were 207 CpG sites commonly related to vitamin C ingestion and the relative abundance of Actinobacteria. From these sites, there were 13 sites hypomethylated and 103 hypermethylated. The hypomethylated targets involved the respective processes: immune function, glucose homeostasis, and general cellular metabolism. The hypermethylated sites were also enriched in immune function-related processes, and interestingly, more immune responses against pathogens were detected. These findings contribute to understanding the interaction between nutrients, microbiota, DNA methylation, and the immune response.

Comparison between dual-energy x-ray absorptiometry and bioelectrical impedance for body composition measurements in adults with chronic kidney disease: A cross-sectional, longitudinal, multi-treatment analysis.

OBJECTIVE: The aim of this study was to evaluate the agreement between bioelectrical impedance spectroscopy (BIS) and dual-energy x-ray absorptiometry (DXA) for assessment of body composition in patients with chronic kidney disease (CKD). METHODS: We performed cross-sectional and prospective analyses by DXA and BIS in whole body (BISWB) and segmental (BISSEG) protocols in CKD non-dialysis-dependent (n = 81), hemodialysis (n = 83), peritoneal dialysis (n = 24), and renal transplantation (n = 80) patients. Intraclass correlation coefficient (ICC) and Bland-Altman plots were evaluated. Linear regression analysis was performed for bias assessment and development of equations. Receiver operating characteristics curve was constructed for diagnosis of inadequate error tolerance (DXA - BIS >±2kg). RESULTS: The agreement with DXA was greater for BISWB than BISSEG; for fat mass (FM; ICC men = 0.894; women = 0.931) than fat-free mass (FFM; ICC men = 0.566; women = 0.525), with greater bias for FFM as muscle increases and for FM in body fat extremes. The agreement was lower for body change analysis (ICC FFM men = 0.196; women = 0.495; ICC FM men = 0.465; women = 0.582). The ratio of extra- to intracellular water (ECW/ICW), body mass index, fat mass index, waist circumference, resistance, and reactance interfered in bias between methods. An ECW/ICW cutoff point of ≥0.7250 for inadequate error tolerance was determined. New prediction equations for FFM (r2 = 0.913) and FM (r2 = 0.887) presented adequate error tolerance in 55% and 63% compared with 30% and 39% of the original equation, respectively. CONCLUSION: For body composition evaluation in patients with CKD, BIS applied using the whole body protocol, in normal hydration patients with CKD is as reliable as DXA; BIS must be used with caution in overhydration patients with ECW/ICW ≥ 0.7250. The newly developed equations are indicated for greater precision.

Chronic kidney disease under non-dialysis dependent, hemodialysis, peritoneal dialysis and kidney transplant treatment: Body composition data.

This article presents a dataset of body composition in chronic kidney disease (CKD) non-dialysis-dependent (NDD), hemodialysis (HD) and peritoneal dialysis (PD) (for at least 3 months), and kidney transplantation (KTx) (for at least 6 months) patients. The data were collected as part of a PhD research project, an observational cross-sectional study followed by a prospective analysis (about 6 months later). Adult CKD patients (18≤age≤60 years old) from a tertiary hospital were recruited: CKD in stages 3b to 5 for NDD patients; PD patients without peritonitis in the last 30 days; HD patients in 4-hour dialysis session, 3 times per week, through an arteriovenous fistula; and KTx patients with CKD in stages 1 to 3a. Patients with presence of amputated limbs or an electronic implant, wheelchair user or inpatient, body weight above 140 kg or BMI higher than 40 kg/m2, acute infections, cancer diagnosis, acquired immunodeficiency syndrome, and others that could alter body composition were excluded. The dataset in this publication consist of some clinical measurements for characterization of the sample, body composition measurements by dual-energy X-ray absorptiometry and by bioelectrical impedance spectroscopy in tetra-polar whole-body wrist to ankle (BISWB) and segmental (BISSEG) protocols of 266 CKD patients, being 137 men and 129 women; 81 in NDD treatment, 83 in HD, 24 in PD, and 80 in KTx. Measurements were performed consecutively by the same professional after an 8-hour fast, empty urinary bladder, drainage of the peritoneal dialysate, and just after the midweek hemodialysis session. To analyze differences among subgroups according to sex and CKD treatment, unpaired T test or ANOVA and Chi-square, adjusted by Bonferroni post-test, were applied. Agreement in fat free mass and fat mass measurements between BISWB and BISSEG, for cross-sectional data and for body composition changes (prospective measurement - cross-sectional measurement), was checked using intraclass correlation coefficient and 95% confidence intervals. Agreement on individual level was evaluated using the Bland-Altman method with limits of agreement. The data can be valuable in the study of body composition in CKD under all types of treatment and also for agreement analysis among body composition measurements by different instruments and techniques. The data are analysed and interpreted in the research article Bellafronte et al., 2020 [1].