pyrophosphate and Phosphorus-Metabolism-Disorders

Topics: Bone and Bones; Bone Development; Bone Diseases; Calcitonin; Calcium Metabolism Disorders; Child, Preschool; Densitometry; Diphosphates; Homeostasis; Humans; Hyperparathyroidism; Hypophosphatasia; Hypophosphatemia, Familial; Infant; Metabolism, Inborn Errors; Microradiography; Osteogenesis Imperfecta; Osteoporosis; Parathyroid Glands; Parathyroid Hormone; Phosphorus Metabolism Disorders; Pseudohypoparathyroidism; Rickets; Vitamin D

In calcium pyrophosphate dihydrate (CPPD) crystal deposition disease, metabolic abnormalities favoring extracellular inorganic pyrophosphate (PPi) accumulation have been suspected. Elevations of intracellular PPi in cultured skin fibroblasts from a single French kindred with familial CPPD deposition (19) and elevated nucleoside triphosphate pyrophosphohydrolase activity (NTPPPH), which generates PPi in extracts of CPPD crystal-containing cartilages (14) favor this suspicion. To determine whether NTPPPH activity or PPi content of cells might be a disease marker expressed in extraarticular cells, human skin-derived fibroblasts were obtained from control donors and patients affected with the sporadic and familial varieties of CPPD (CPPD-S and CPPD-F) deposition. Intracellular PPi was elevated in both CPPD-S (P less than 0.05) and CPPD-F (P less than 0.01) fibroblasts compared with control fibroblasts. Ecto-NTPPPH activity was elevated in CPPD-S (P less than 0.01) but not CPPD-F. Intracellular PPi correlated with ecto-NTPPPH (P less than 0.01). Elevated PPi levels in skin fibroblasts may serve as a biochemical marker for patients with familial or sporadic CPPD crystal deposition disease; ecto-NTPPPH activity further separates the sporadic and familial disease types. Expression of these biochemical abnormalities in nonarticular cells implies a generalized metabolic abnormality.

Topics: Calcium Pyrophosphate; Cells, Cultured; Crystallization; Diphosphates; Fibroblasts; Humans; Phosphorus Metabolism Disorders; Pyrophosphatases; Skin

Topics: Absorptiometry, Photon; Acidosis, Renal Tubular; Adolescent; Bone and Bones; Bone Diseases; Child; Child, Preschool; Diphosphates; Fanconi Syndrome; Humans; Kidney Diseases; Osteomalacia; Phosphorus Metabolism Disorders; Radionuclide Imaging; Renal Tubular Transport, Inborn Errors; Technetium