Results: Seven of 18 patients had pathogenic NPH-causing mutations in NPHP1, NPHP3, NPHP4, or CEP164. Compared with patients without pathogenic mutations, those with pathogenic mutations were significantly younger but did not significantly differ in the classic NPH pathologic findings, such as tubular cysts. On the other hand, the number of tubules with thick tubular basement membrane (TBM) duplication, which was defined as >10-mm thickness, was significantly higher in patients with genetically proven adult NPH than in those without pathogenic mutations. a-Smooth muscle actin (a-SMA)-positive myofibroblasts were detected inside thick TBM duplication. Conclusions:In adult patients with NPH, thick TBM duplication was the specific finding. Our analysis also suggested that older patients tended to have no pathogenic mutations, even when they were suspected to have NPH by renal biopsy. These findings could be the novel clinical clue for the diagnosis of NPH in adult patients.

Calcium sensing receptor is an important target for the treatment of secondary hyperparathyroidism (SHPT). Etelcalcetide hydrochloride is a novel peptide calcimimetic agent that has a similar mechanism of action as cinacalcet hydrochloride. Clinical trials of etelcalcetide have been performed in the US, Europe, and Japan, and these trials demonstrated the safety and efficacy of etelcalcetide in dialysis patients. Etelcalcetide has recently been approved in Europe, the US and Japan. Areas covered: We review the development, pharmacokinetics, and clinical efficacy and safety of etelcalcetide for the treatment of SHPT in hemodialysis patients. We also summarize the clinical evidence regarding cinacalcet to forecast the potential clinical benefit of etelcalcetide. Expert opinion: Etelcalcetide is an injectable calcimimetic with a longer elimination half-life than cinacalcet. The injectable formulation improves adherence and reduces pill burden, while the frequency of gastrointestinal adverse events has been comparable between cinacalcet and etelcalcetide. The longer half-life of etelcalcetide reduces the fluctuation of biochemical markers of mineral and bone metabolism, but it remains to be determined whether such a sustained effect results in improved outcomes. Further studies are needed to determine the impact of etelcalcetide on clinical outcomes, particularly in comparison with the conventional calcimimetic cinacalcet.

Rationale & Objective Patients with chronic kidney failure have markedly elevated fibroblast growth factor 23 (FGF-23) levels and decreased soluble Klotho levels. However, no studies have examined the effects of hemodialysis initiation on the levels of these hormones and other parameters of mineral metabolism. Study Design Prospective single-arm study. Setting & Participants 20 individuals with incident kidney failure initiating hemodialysis. Exposure Initiation of hemodialysis. Dose adjustments of phosphate binders and vitamin D receptor activators and use of calcimimetics, erythropoiesis-stimulating agents, and intravenous iron were prohibited. Outcomes Changes in serum levels of FGF-23, soluble Klotho, and other biochemical parameters of mineral metabolism, measured before and after each hemodialysis session, for a total of 4 sessions over 5 days. Analytical Approach Repeated-measures analysis of variance. Results At baseline, participants had 18-fold higher median FGF-23 levels and 1.6-fold lower mean soluble Klotho levels compared with age- and sex-matched healthy individuals. Initiation of hemodialysis led to progressive reductions in serum phosphorus, intact parathyroid hormone, and FGF-23 levels, with dialysis-related fluctuations. No reductions were observed in levels of α 1 -microglobulin, which has molecular weight comparable to FGF-23. The magnitude of the FGF-23 level reductions was strongly associated with concomitant changes in serum phosphorus levels but not with the changes in intact parathyroid hormone levels. Soluble Klotho levels did not change after the initiation of hemodialysis. Limitations Single-arm design, small sample size, short follow-up period. Conclusions Initiation of hemodialysis in patients with chronic kidney failure led to progressive reductions in FGF-23 levels in association with reductions in serum phosphorus levels. These results suggest that phosphorus is a strong inducer of FGF-23 production and that regulation of FGF-23 production is a rapid process.

No abstract

No abstract