cholecalciferol and Hyperphosphatemia

Denosumab can improve bone health in advanced kidney disease (CKD) but is associated with hypocalcemia. We created a clinical care pathway focused on the safe provision of denosumab in advanced CKD that reduced the risk of hypocalcemia by 37% at our hospital. Similar pathways could be adopted and tested in other centers.. There is an increased risk of hypocalcemia with denosumab in advanced chronic kidney disease (CKD). We aimed to reduce the proportion of patients with advanced CKD who experienced denosumab-induced hypocalcemia at our center.. There were 6 patients with advanced CKD treated with denosumab prior to the implementation of our care pathway (March 2015-October 2020; 83% receiving dialysis). At the time of their denosumab injection, 83% were using 500-1000 mg of calcium, and 83% used 1000-2000 IU of vitamin D. A clinical care pathway focused on the safe provision of denosumab in advanced CKD reduced the risk of hypocalcemia in patients treated in our hospital. Similar pathways could be adopted and tested in other centers.

Topics: Bone Density Conservation Agents; Calcium; Cholecalciferol; Denosumab; Humans; Hypercalcemia; Hyperphosphatemia; Hypocalcemia; Quality Improvement; Renal Insufficiency, Chronic

Klotho is an aging-suppressor gene. The purpose of this study was to investigate whether Klotho deficiency affects arterial structure. We found that Klotho-deficient (kl/kl) mice developed severe arterial calcification and elastin fragmentation. Klotho-deficient mice demonstrated higher levels of bone morphogenetic proteins (BMP2, BMP4) and runt-related transcription factor 2 (RUNX2) in aortas, indicating that Klotho deficiency upregulates expression of BMP2 and RUNX2 (a key transcription factor in osteoblasts). To exclude the potential involvement of hyperphosphatemia in arterial calcification, Klotho-deficient mice were given a low phosphate diet (0.2%). The low phosphate diet normalized blood phosphate levels and abolished calcification in the lungs and kidneys, but it did not prevent calcification in the aortas in Klotho-deficient mice. Thus, Klotho deficiency per se might play a causal role in the pathogenesis of arterial calcification, which is independent of hyperphosphatemia. In cultured mouse aortic smooth muscle cells (ASMCs), Klotho-deficient serum-induced transition of ASMCs to osteoblasts. Klotho-deficient serum promoted BMP2/vitamin D3-induced protein expression of PIT2 and RUNX2, phosphorylation of SMAD1/5/8 and SMAD2/3, and extracellular matrix calcification. Interestingly, treatments with recombinant Klotho protein abolished BMP2/vitamin D3-induced osteoblastic transition and morphogenesis and calcification. Therefore, Klotho is a critical regulator in the maintenance of normal arterial homeostasis. Klotho deficiency-induced arterial calcification is an active process that involves the osteoblastic transition of SMCs and activation of the BMP2-RUNX2 signaling.

Topics: Animals; Calcinosis; Cells, Cultured; Cholecalciferol; Core Binding Factor Alpha 1 Subunit; Glucuronidase; Hyperphosphatemia; Klotho Proteins; Mice; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phosphates

Cardiovascular disease is the primary cause of mortality in patients with chronic kidney disease. Vascular calcification (VC) in the medial layer of the vessel wall is a unique and prominent feature in patients with advanced chronic kidney disease and is now recognized as an important predictor and independent risk factor for cardiovascular and all-cause mortality in these patients. VC in chronic kidney disease is triggered by the transformation of vascular smooth muscle cells (VSMCs) into osteoblasts as a consequence of elevated circulating inorganic phosphate (P. Using primary mouse and human VSMCs, we found that TDAG51 is induced in VSMCs by P. Our studies highlight TDAG51 as an important mediator of P

Topics: Aged; Animals; Cell Transdifferentiation; Cells, Cultured; Cholecalciferol; Core Binding Factor Alpha 1 Subunit; Disease Models, Animal; Female; Gene Expression Regulation; Humans; Hyperphosphatemia; Male; Mice, Inbred C57BL; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Osteogenesis; Phosphates; Signal Transduction; Sodium-Phosphate Cotransporter Proteins, Type III; Transcription Factors; Vascular Calcification

Reduced homoarginine plasma levels are associated with unfavourable cardiovascular outcome in chronic kidney disease (CKD). Cardiovascular events in CKD are fostered by vascular calcification, an active process promoted by hyperphosphatemia and involving osteo-/chondrogenic transformation of vascular smooth muscle cells (VSMCs). The present study explored the effect of homoarginine on phosphate-induced osteo-/chondrogenic signalling and vascular calcification.. Experiments were performed in hyperphosphatemic klotho-hypomorphic mice (kl/kl), in subtotal nephrectomy and vitamin D3-overload mouse calcification models and in primary human aortic smooth muscle cells (HAoSMCs). As a result, plasma homoarginine levels were lower in kl/kl mice than in wild-type mice and in both genotypes significantly increased by lifelong treatment with homoarginine. Surprisingly, homoarginine treatment of kl/kl mice and of mice with renal failure after subtotal nephrectomy augmented vascular calcification and enhanced the transcript levels of plasminogen activator inhibitor 1 (Pai1) and of osteogenic markers Msx2, Cbfa1, and Alpl. Similarly, homoarginine treatment of HAoSMCs increased phosphate-induced calcium deposition, ALP activity, as well as PAI1, MSX2, CBFA1, and ALPL mRNA levels. Homoarginine alone up-regulated osteo-/chondrogenic signalling and indicators of oxidative stress in HAoSMCs. Furthermore, homoarginine reduced citrulline formation from arginine by nitric oxide (NO) synthase (NOS) isoforms. NO formation by NOS was reduced when using homoarginine as a substrate instead of arginine. The osteoinductive effects of homoarginine were mimicked by NOS inhibitor L-NAME and abolished by additional treatment with the NO donors DETA-NONOate and PAPA-NONOate or the antioxidants TEMPOL and TIRON. Furthermore, homoarginine augmented vascular calcification and aortic osteo-/chondrogenic signalling in mice after vitamin D3-overload, effects reversed by the NO donor molsidomine.. Homoarginine augments osteo-/chondrogenic transformation of VSMCs and vascular calcification, effects involving impaired NO formation from homoarginine.

Topics: Animals; Biomarkers; Calcium; Cell Transdifferentiation; Cells, Cultured; Cholecalciferol; Chondrogenesis; Disease Models, Animal; Dose-Response Relationship, Drug; Gene Expression Regulation; Genetic Predisposition to Disease; Glucuronidase; Homoarginine; Humans; Hyperphosphatemia; Klotho Proteins; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Nephrectomy; Nitric Oxide; Nitric Oxide Donors; Nitric Oxide Synthase; Osteogenesis; Phenotype; Renal Insufficiency; Time Factors; Vascular Calcification

Various complications consequent on disordered calcium and phosphate homeostasis occur frequently in chronic kidney disease (CKD) patients. Particularly, vascular calcification has high morbidity and mortality rates. There is a clear need for a better CKD model to examine various aspects of this disordered homeostasis.. Oral dosing with adenine induced CKD in rats in only 10 days. Serum calcium, phosphate and parathyroid hormone were measured and calcification in aorta was assessed histologically. The effects of varying phosphorus content of diet or treatment with phosphate binders or active vitamin D(3) on these parameters were examined.. After adenine dosing, significant hyperphosphatemia, hypocalcemia and secondary hyperparathyroidism (2HPT) were observed during the experimental period of 15 weeks. Aortic calcification was detected in only some of the animals even at 15 weeks (approximately 40%). Treatment with vitamin D(3) for 18 days, even at a low dose (100 ng x kg(-1), 3-4 times week(-1), p.o), caused aortic calcification in all animals and increases in serum calcium levels up to the normal range. The vitamin D(3)-induced calcification was significantly inhibited by phosphate binders which lowered serum phosphate levels and the calcium x phosphate product, although serum calcium levels were elevated.. These data suggest that rats dosed orally with adenine provide a more useful model for analysing calcium/phosphate homeostasis in severe CKD. Controlling serum calcium/phosphate levels with phosphate binders may be better than vitamin D(3) treatment in hyperphosphatemia and 2HPT, to avoid vascular calcification.

Topics: Adenine; Animals; Aortic Diseases; Biomarkers; Blood Urea Nitrogen; Calcinosis; Calcium; Calcium Carbonate; Chelating Agents; Cholecalciferol; Chronic Disease; Creatinine; Disease Models, Animal; Disease Progression; Hyperparathyroidism, Secondary; Hyperphosphatemia; Hypocalcemia; Kidney Diseases; Male; Parathyroid Hormone; Phosphates; Polyamines; Rats; Rats, Wistar; Sevelamer; Severity of Illness Index; Time Factors