Vitamin D deficiency in chronic kidney disease: Myth or reality?

Crosstalk between kidney and bones: New perspective for modulating osteoporosis

Growing evidence indicates an interesting interplay between kidney and bone. The pathophysiological condition of the skeletal system is intricately associated with the normal functioning of the kidneys. This relationship is modulated by various factors, including calcium and phosphate, 1-α-hydroxylase, erythropoietin (EPO), klotho, fibroblast growth factor 23 (FGF23), bone morphogenetic protein-7 (BMP-7), and extracellular vesicles (EVs). These interactions are notably evident in conditions such as chronic kidney disease with bone mineral density (CKD-BMD), renal osteodystrophy (ROD), and osteoporosis (OP). Furthermore, innovative methodologies such as cell co-culture, organ-on-a-chip, single-cell sequencing, and spatial transcriptomics are highlighted as instrumental in advancing the study of inter-organ interactions. This review, grounded in the pathogenesis, diagnostic and therapeutic modalities, and pharmacological treatments of OP, synthesizes evidence from molecular biology to clinical perspectives. It aims to establish a foundation for the development of more complex and physiologically relevant in vitro models and to propose potential therapeutic strategies.

Astragalus polysaccharide protects sepsis model rats after cecum ligation and puncture

To investigate the protective effect and mechanism of Astragalus polysaccharide (APS) on septic rats, the present project applied APS at concentrations of 400, 600, and 800 mg/kg/d to rats for prophylactic administration for 7 d, and a rat sepsis model was constructed by the cecum ligation and puncture (CLP) method. Forty-eight rats were divided into six groups of eight each. Each experiment was repeated at least three times. Rat serum levels of VD₃, 25(OH)D₃, 1,25(OH)₂D₃, IL-6, TNF-α, CRP, sICAM-1, corticosterone (CORT), and short-chain fatty acids (SCFAs) in each group were detected, and renal damage was observed by H&E. We also determined the protein expression of CYP27B1, CYP24A1, vitamin D receptor (VDR), steroidogenic acute regulatory protein (STAR), 3β-hydroxysteroid dehydrogenase (3β-HSD), CYP21A2, CYP17A1, and CYP11B1. An operational taxonomic unit (OTU) was used to determine the gut microbiota diversity of septic rats after prophylactic administration and before modeling. Results revealed that APS markedly increased the contents of 25(OH)D₃ and 1,25(OH)₂D₃ but greatly decreased those of TNF-α, IL-6, CRP, sICAM-1, and CORT. APS alleviated renal tubular dilation and vascular congestion in rat kidneys and substantially reduced renal cell apoptosis. Moreover, the expression of CYP24A1, VDR, CYP11B1, CYP21A2, CYP17A1, STAR, and 3β-HSD in the kidneys of the H-APS group was substantially decreased compared to that of the model group, whereas CYP27B1 was markedly increased. GC-MS detection indicated a substantial increase in SCFAs and acetic acid content in the H-APS group versus model group. Through 16S sequencing, the abundance of genus and gut microbiota species increased in the APS groups compared to that of the control group. Taken together, APS increased the activity of the vitamin D axis, inhibited the production of inflammatory factors in the body, altered the structure of rat intestinal flora, and increased the amount of acetic acid and SCFAs in rats, thereby effectively hindering inflammation and organ damage in septic rats.