Comparison of the effects of novel vitamin D receptor analog VS-105 and paricalcitol on chronic kidney disease-mineral bone disorder in an experimental model of chronic kidney disease

Development of animal models with chronic kidney disease-mineral and bone disorder based on clinical characteristics and pathogenesis

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a systemic complication of chronic kidney disease (CKD), resulting in high morbidity and mortality. However, effective treatment strategies are lacking. The pathogenesis of CKD-MBD is unclear but involves feedback mechanisms between calcium, phosphorus, parathyroid hormone, vitamin D and other factors, in addition to FGF23, Klotho, Wnt inhibitors, and activin A. Construction of a perfect animal model of CKD-MBD with clinical characteristics is important for in-depth study of disease development, pathological changes, targeted drug screening, and management of patients. Currently, the modeling methods of CKD-MBD include surgery, feeding and radiation. Additionally, the method of CKD-MBD modeling by surgical combined feeding is worth promoting because of short time, simplicity, and low mortality. Therefore, this review based on the pathogenesis and clinical features of CKD-MBD, combined with the current status of animal models, outlines the advantages and disadvantages of modeling methods, and provides a reference for further CKD-MBD research.

Vascular Calcification in Chronic Kidney Disease: An Update and Perspective

Chronic kidney disease is a devastating condition resulting from irreversible loss of nephron numbers and function and leading to end-stage renal disease and mineral disorders. Vascular calcification, an ectopic deposition of calcium-phosphate salts in blood vessel walls and heart valves, is an independent risk factor of cardiovascular morbidity and mortality in chronic kidney disease. Moreover, aging and related metabolic disorders are essential risk factors for chronic kidney disease and vascular calcification. Marked progress has been recently made in understanding and treating vascular calcification in chronic kidney disease. However, there is a paucity of systematic reviews summarizing this progress, and investigating unresolved issues is warranted. In this systematic review, we aimed to overview the underlying mechanisms of vascular calcification in chronic kidney diseases and discuss the impact of chronic kidney disease on the pathophysiology of vascular calcification. Additionally, we summarized potential clinical diagnostic biomarkers and therapeutic applications for vascular calcification with chronic kidney disease. This review may offer new insights into the pathogenesis, diagnosis, and therapeutic intervention of vascular calcification.

Calcipotriol attenuates liver fibrosis through the inhibition of vitamin D receptor-mediated NF-κB signaling pathway

Liver fibrosis is an inevitable stage in the development of chronic liver disease to cirrhosis. Nonetheless, the interventional treatment and achieving control over the disease at this stage can substantially reduce the incidence of liver cirrhosis. To demonstrate these aspects, liver pathological sections of 18 patients with chronic liver disease are collected for research according to the degree of fibrosis. Further, the expressions of related proteins in each group are studied by the Western blot method. The cell proliferation and apoptosis are detected by CKK-8 and flow cytometry analyses. Further, a rat model with carbon tetrachloride (CCl₄)-induced liver fibrosis is employed to verify the effect and mechanism of VDR on the process of liver fibrosis in vivo. The expression of VDR in liver tissues of patients with liver fibrosis is negatively correlated with α-smooth muscle actin (α-SMA), Col-1, and liver fibrosis stages. Moreover, the tumor necrosis factor (TNF)-α stimulation could increase the proliferation of LX-2, up-regulate the expression of α-SMA, Col-1, NF-κB, p-IκBα, p-IKKβ, p-p65m, and some fibrosis factors, as well as down-regulate the expressions of VDR and matrix metalloproteinase-1 (MMP-1). Considering the protective actions of VDR, calcipotriol, a VDR agonist, effectively reduced the degree of liver fibrosis in a rat model of liver fibrosis by inhibiting the deposition of extracellular (ECM) and activation of hepatic stellate cells (HSCs), which is negatively correlated with the degree of liver fibrosis. Together, these shreds of evidence demonstrated that the calcipotriol showed great potential in effectively attenuating liver fibrosis.

Effects of Paricalcitol on Body Composition in Vitamin D-Deficient Rats

Background

Paricalcitol has been proposed for the treatment of secondary hyperparathyroidism in patients with renal failure and vitamin D deficiency (VDD); however, VDD is related to a range of clinical complaints. We aimed to investigate the effects of paricalcitol on body composition in VDD rats.

Methods

Thirty adult male rats aged 10 weeks were randomly divided into three groups of 10, comprising control, VDD, and VDD plus paricalcitol (32 ng/rat intraperitoneal injection) (VDD+P), at the Animal Lab of the Endocrinology and Metabolism Research Center, Shiraz, Iran, in 2020. Body composition was assessed after three weeks via serum biochemical tests and dual-energy X-ray absorptiometry. Finally, the data were analyzed by using the paired-sample t test, the one-way ANOVA, and the Tukey post hoc test.

Results

Global lean mass and fat mass were lower in the VDD and VDD+P groups than in the controls (P<0.001). Global fat percentage was reduced significantly in the VDD+P group (P=0.029).

Conclusion

Paricalcitol reduced global fat mass and fat percentage in a rat model with VDD. Evaluation of insulin and adiponectin levels is suggested to clarify the physiology of paricalcitol in VDD states.