cardiovascular-agents and sodium-thiosulfate

This review summarizes current understanding of generalized arterial calcification of infancy (GACI), emphasizing pathophysiology, clinical presentation, and approaches and controversies in management.. Identification of causative ENPP1 mutations revealed that GACI arises from deficiencies in inorganic pyrophosphate (leading to calcifications) and adenosine monophosphate (leading to intimal proliferation). Identification of genotypic and phenotypic overlap with pseudoxanthoma elasticum and autosomal recessive hypophosphatemic rickets further advanced understanding of GACI as a complex, multisystemic disease. Clinical data is limited to small, retrospective samples; it is therefore unknown whether commonly used medications, such as bisphosphonates and hypophosphatemia treatment, are therapeutic or potentially harmful. ENPP1-Fc replacement represents a promising approach warranting further study. Knowledge gaps in natural history place clinicians at high risk of assigning causality to interventions that are correlated with changes in clinical status. There is thus a critical need for improved natural history studies to develop and test targeted therapies.

Topics: Adenosine Monophosphate; Bone Density Conservation Agents; Calcinosis; Cardiovascular Agents; Chelating Agents; Diphosphates; Diphosphonates; Familial Hypophosphatemic Rickets; Genotype; Hearing Loss; Humans; Multidrug Resistance-Associated Proteins; Phenotype; Phosphoric Diester Hydrolases; Pseudoxanthoma Elasticum; Pyrophosphatases; Thiosulfates; Tooth Diseases; Vascular Calcification; Vitamin D

Vascular calcification is a major cause of morbidity and mortality in dialysis patients. Human and animal studies indicate that sodium thiosulfate (STS) may prevent the progression of vascular calcifications. The pharmacokinetics of STS in hemodialysis patients has not been investigated yet.. STS was given intravenously to 10 hemodialysis patients on- and off-hemodialysis. Additionally, STS was applied to 9 healthy volunteers once intravenously and once orally. Thiosulfate concentrations were measured by using a specific and sensitive HPLC method.. In volunteers and patients, mean endogenous thiosulfate baseline concentrations were 5.5 ± 1.82 versus 7.1 ± 2.7 μmol/L. Renal clearance was high in volunteers (1.86 ± 0.45 ml/min per kg) and reflected GFR. Nonrenal clearance was slightly, but not significantly, higher in volunteers (2.25 ± 0.32 ml/min per kg) than in anuric patients (2.04 ± 0.72 ml/min per kg). Hemodialysis clearance of STS was 2.62 ± 1.01 ml/min per kg. On the basis of the nonrenal clearance and the thiosulfate steady-state serum concentrations, a mean endogenous thiosulfate generation rate of 14.6 nmol/min per kg was calculated in patients. After oral application, only 4% of STS was recovered in urine of volunteers, reflecting a low bioavailability of 7.6% (0.8% to 26%).. Given the low and variable bioavailability of oral STS, only intravenous STS should be prescribed today. The biologic relevance of the high hemodialysis clearance for the optimal time point of STS dosing awaits clarification of the mechanisms of action of STS.

Topics: Administration, Oral; Adult; Aged; Biological Availability; Biotransformation; Cardiovascular Agents; Chi-Square Distribution; Chromatography, High Pressure Liquid; Female; Glomerular Filtration Rate; Humans; Injections, Intravenous; Kidney; Kidney Diseases; Male; Middle Aged; Models, Biological; Renal Dialysis; Switzerland; Thiosulfates