Identification of sarcopenia and dynapenia in CKD predialysis patients with EGWSOP2 criteria: An observational, cross-sectional study

Objectives: Using the new European Working Group on Sarcopenia in Older People (EWGSOP2) criteria, we identified sarcopenic and dynapenic patients in a cohort of predialysis patients with chronic kidney disease (CKD), and evaluated their clinical and laboratory characteristics. Methods: The study population consisted of 85 (55 men) clinically stable predialysis CKD patients (92.9% in stages 3–5), with a median age of 65.0 (52.5–72.0) y. We classified as sarcopenic the patients with handgrip strength (HGS) and muscle mass both lower than the respective EWGSOP2 cutoff values and as dynapenic those in whom only HGS was less than these reference values. HGS was measured with a hand dynamometer, whereas muscle mass was measured by bioimpedance analysis. Renal function was evaluated as Modification of Diet in Renal Disease estimated glomerular filtration rate. Results: The prevalence of sarcopenia and dynapenia was, respectively, 7.1% and 17.6%. As reported in previous studies, serum albumin and hemoglobin were lower in sarcopenic patients than in patients with preserved muscle mass and strength. However, unlike in these studies, sarcopenia prevalence did not increase with CKD stage, and estimated glomerular filtration rate was similar between groups. Moreover, no difference was identified in any of the aforementioned parameters between dynapenic patients and patients with preserved muscle mass and strength. Conclusions: The EWGSOP2 criteria identified sarcopenia in CKD with a prevalence similar to previous diagnostic criteria. In addition, they found that dynapenia was highly prevalent. Nevertheless, the EWGSOP2 criteria could be better adapted to CKD patients to improve their ability to detect high-risk sarcopenic and dynapenic patients

Sulfate-dependant microbially induced corrosion of mild steel in the deep sea: a 10-year microbiome study.

BACKGROUND: Metal corrosion in seawater has been extensively studied in surface and shallow waters. However, infrastructure is increasingly being installed in deep-sea environments, where extremes of temperature, salinity, and high hydrostatic pressure increase the costs and logistical challenges associated with monitoring corrosion. Moreover, there is currently only a rudimentary understanding of the role of microbially induced corrosion, which has rarely been studied in the deep-sea. We report here an integrative study of the biofilms growing on the surface of corroding mooring chain links that had been deployed for 10 years at ~2 km depth and developed a model of microbially induced corrosion based on flux-balance analysis. METHODS: We used optical emission spectrometry to analyze the chemical composition of the mooring chain and energy-dispersive X-ray spectrometry coupled with scanning electron microscopy to identify corrosion products and ultrastructural features. The taxonomic structure of the microbiome was determined using shotgun metagenomics and was confirmed by 16S amplicon analysis and quantitative PCR of the dsrB gene. The functional capacity was further analyzed by generating binned, genomic assemblies and performing flux-balance analysis on the metabolism of the dominant taxa. RESULTS: The surface of the chain links showed intensive and localized corrosion with structural features typical of microbially induced corrosion. The microbiome on the links differed considerably from that of the surrounding sediment, suggesting selection for specific metal-corroding biofilms dominated by sulfur-cycling bacteria. The core metabolism of the microbiome was reconstructed to generate a mechanistic model that combines biotic and abiotic corrosion. Based on this metabolic model, we propose that sulfate reduction and sulfur disproportionation might play key roles in deep-sea corrosion. CONCLUSIONS: The corrosion rate observed was higher than what could be expected from abiotic corrosion mechanisms under these environmental conditions. High corrosion rate and the form of corrosion (deep pitting) suggest that the corrosion of the chain links was driven by both abiotic and biotic processes. We posit that the corrosion is driven by deep-sea sulfur-cycling microorganisms which may gain energy by accelerating the reaction between metallic iron and elemental sulfur. The results of this field study provide important new insights on the ecophysiology of the corrosion process in the deep sea