Enhancement of Ionized Calcium and 1,25-Dihydroxycholecalciferol Loss from Peritoneal Fluid during Peritonitis in Patients Treated with Continuous Ambulatory Peritoneal Dialysis

Abstract

This study was to evaluate whether peritoneal loss of vitamin D metabolites during peritonitis leads to more depletion of 1,25-hydroxycholecalciferol [1,25(OH)₂D₃] and 25-hydroxycholecalciferol [25(OH)D] in continuous ambulatory peritoneal dialysis (CAPD) patients, especially in the high peritonitis occurrence group (HPOG). A series of ionized calcium, pH values, 1,25(OH)₂D₃ and 25(OH)D levels in dialysate during peritonitis were studied in 30 CAPD patients. In addition, bone mineral content (BMC) was determined during peritonitis. On the basis of peritonitis occurrence, 14 patients were in the low peritonitis occurrence group (LPOG) and 6 patients in the HPOG. Increase in peritoneal loss of ionized calcium, 1,25(OH)₂D₃, 25(OH)D and a decrease of pH value in dialysate may appear in the early period of peritonitis in both groups. When peritonitis occurs too frequently in a short period, the peritoneal membrane function cannot recover completely. Frequent peritonitis may impair peritoneal function and cause persistent loss of calcium. 1,25(OH)₂D₃ amd 25(OH)D loss is also higher in the HPOG than in the LPOG. The persistent loss of calcium, low plasma vitamin D levels and increased parathyroid hormone level with hyperparathyroidism in the HPOG are the important factors contributing to renal osteodystrophy. The lower BMC in the bone study confirmed this. Therefore, adequate calcium and vitamin D supplementation is necessary in the HPOG.

Calcium-sensing receptors signal constitutive macropinocytosis and facilitate the uptake of NOD2 ligands in macrophages

“…Our findings extend the immune function of CaSR in myeloid cells. It is relevant that extracellular calcium is elevated at sites of inflammation and injury 49 . CaSR may function in the migration towards, and acquisition of antigen at sites of injury and inflammation, thereby assisting the immune surveillance function of antigen-presenting cells.…”

Extracellular calcium sensing promotes human B-cell activation and function

“…For example, calcium is known to be released by injured and/or dying cells at sites of inflammation, producing calcium concentrations 1.5-to 3-fold higher than in serum. [63][64][65] Ca 2ϩ o levels may also rise near B cells when neighboring cells are activated (for example, T cells stimulated by antigen in a lymph node). When activated cells release Ca 2ϩ from their internal stores, they subsequently pump cytosolic calcium into the extracellular environment to restore homeostatic Ca 2ϩ i levels (20-100 nM).…”

Serial Changes of lnterleukin-6 and lnterleukin-8 Levels in Drain Dialysate of Uremic Patients with Continuous Ambulatory Peritoneal Dialysis during Peritonitis

“…All patients had a Tenckhoff peritoneal catheter. The daily dietary protein intake was around 1.4 g/kg body weight and the calorie intake 27 kcal/kg body weight, but additional calories were assumed to be derived from dextrose in the dialysis fluid [10]. The total daily calorie content of the fluids used for each patient was calculated at 3.8 kcal/g dextrose.…”