New clinical trials with vitamin D and analogs in renal disease

Chronic kidney disease: a new look at pathogenetic mechanisms and treatment options

The concept of renoprotection has evolved significantly, driven by improved understanding of the pathophysiology of chronic kidney disease (CKD) and the advent of novel treatment options. Glomerular hyperfiltration, hypertension and proteinuria represent key mediators of CKD progression. It is increasingly recognized that proteinuria may actually be pathological and etiological in CKD progression and not just symptomatic. It initiates a sequence of events involving activation of proinflammatory and profibrotic signaling pathways in proximal tubular epithelial cells with transmission of the disease to the tubulointerstitium and progression to end-stage kidney disease (ESKD). Although the etiology and epidemiology of pediatric CKD differs to that in adults, studies in the various animal models of kidney disease, from obstructive uropathy to glomerulonephritis, have revealed that many common proinflammatory and profibrotic pathways are induced in progressive proteinuric CKD, irrespective of the primary disease. This pathomechanistic overlap therefore translates into the potential for common treatment targets for a wide spectrum of kidney diseases. In this review we therefore discuss the experimental and clinical evidence for an array of prospective future drug treatments of CKD progression. While conceptually promising, clear definitive evidence beyond preclinical data does not exist for many of these treatments, and others are limited by serious adverse effects. More studies are needed before general recommendations can be given.

Comparison of oral and intravenous alfacalcidol in chronic hemodialysis patients

Background

Activated vitamin D is the mainstay of treatment for secondary hyperparathyroidism (SHPT) in chronic hemodialysis patients. However, the optimal route of administration is still debated. The aim of our study was to compare efficacy of oral vs intravenous (IV) administration of alfacalcidol in hemodialysis. A secondary objective was to determine the cost-effectiveness advantage of oral administration.

Methods

Eighty-eight chronic hemodialysis patients receiving IV alfacalcidol three times a week were included in the study. All were switched to the same dose of alfacalcidol given orally three times a week during the hemodialysis session. A budget impact analysis was performed.

Results

Mean patient age was 64 years old and 43% were males. The mean alfacalcidol dose administered was 2.1 μg three times a week. After three months, serum parathormone (PTH) levels decreased from 80 to 59 pmol/L (p = 0.001) and total serum calcium levels increased from 2.34 to 2.40 mmol/L (p = 0.002). After six months, total serum calcium levels were still significantly higher. Alfacalcidol dosage was significantly decreased during study period; the mean reduction was 0.44 μg per dose. Finally, oral administration was associated with an annual cost reduction of 197 678$CAN and an annual nursing time reduction of 25 days.

Conclusion

Our findings support that switching IV to oral administration of alfacalcidol during hemodialysis sessions may lead to a similar control of SHPT with lower doses of activated vitamin D. This is a good strategy for optimizing compliance and may allow a dose reduction because of a greater efficacy to suppress PTH. Oral administration also has significant cost-effectiveness advantages.

The study of serum vitamin d and insulin resistance in chinese populations with normal glucose tolerance

Objectives. The aim of this study was to investigate the relationship between serum vitamin D and insulin resistance in Chinese subjects without diabetes mellitus. Methods. Serum 25(OH)D was measured in 897 individuals with normal glucose tolerance (NGT). Oral glucose tolerance tests (OGTTs) were conducted to exclude cases with diabetes, impaired fasting glucose (IFG), and impaired glucose tolerance (IGT). Metabolic parameters were measured and compared between the highest and lowest 25(OH)D quartiles. The relationship between serum 25(OH)D and homeostatic model assessment-insulin resistance (HOMA-IR) was analyzed. Results. Indexes, such as HOMA-IR, FINS, and SBP, were negatively correlated with serum 25(OH)D concentrations. Compared with the lowest quartile, individuals in the highest group had decreased Lg (HOMA-IR), Lg (FINS), and SBP. Pearson correlation analyses showed that serum 25(OH)D was negatively associated with age, BMI, Lg (HOMA-IR), and Lg (FINS). Multivariate linear regression analysis confirmed the negative correlation of Lg (HOMA-IR) and 25(OH)D. Conclusions. This study showed that serum 25(OH)D could be regarded as an independent predictor of insulin resistance for subjects without diabetes mellitus in China. Adequate vitamin D supplementation may improve multiple metabolic disturbances.