pyrophosphate and Calcium-Metabolism-Disorders

Pyrophosphate and diphosphonates produce striking results on calcium metabolism in experimental animals and man. Compounds containing P-O-P- bonds (e.g. inorganic pyrophosphate [PP-ii1 or P-C-P bonds (diphosponates) inhibit both the formation and dissolution of calcium phosphate crystals in vitro. PP-i may have a physiological function in regulating calcification and bone turnover, and obnormalities in its metabolism may occur in some human diseases notably hypophosphatasia and pseudogout. Diphosphonates inhibit ectopic calcification, and slow down resorption and bone turnover in several experimental systems in vivo. They have helped in studies of various aspects of the regulation of calcium metabolism. The diphosphonate, disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP) has been shown in clinical studies to be effective against ectopic calcification particularly in myositis ossificans progressiva and in disorders of increased bone resorption such as Paget's diseases and some types of osteoporosis. -99mTechnetium complexes of EHDP, PP-i and other polyphosphates have also recently been used successfully as bone scanning agents.

Topics: Animals; Bone and Bones; Bone Resorption; Calcification, Physiologic; Calcinosis; Calcium; Calcium Metabolism Disorders; Cartilage; Chemical Phenomena; Chemistry; Culture Techniques; Depression, Chemical; Diphosphates; Etidronic Acid; Humans; Hydroxyapatites; Kidney Diseases; Methylene Chloride; Organophosphonates; Organophosphorus Compounds; Osteoporosis; Urinary Bladder Calculi; Vitamin D

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 subjects with idiopathic calcium pyrophosphate dihydrate (CPPD) deposition disease, cartilage chondrocytes elaborate increased amounts of PPi. The mechanism of the intracellular PPi elevation is not known. Plasma membrane 5'-nucleotide phosphodiesterase I/nucleotide pyrophosphohydrolase (NTPPPH) activity also is elevated in chondrocytes and dermal fibroblasts of patients with idiopathic CPPD deposition disease. NTPPPH, as an ecto-enzyme, could act within certain intracellular compartments. Thus, we hypothesized a potential causal link between increased NTPPPH activity and increased intracellular PPi.. Transformed simian fibroblasts (COS cells) and human osteoblasts (U2OS cells) were transfected with the 5'-nucleotide phosphodiesterase I ecto-enzyme plasma cell membrane glycoprotein-1 (PC-1), recently shown to be expressed in cartilage, osteoblasts, and fibroblasts.. Transfection with PC-1 markedly up-regulated 5'-nucleotode phosphodiesterase I activity and increased intracellular PPi concentrations by increasing the capacity of cells to generate PPi. Importantly, this did not require supplementation with exogenous nucleotides.. Cellular overexpression of PC-1 produces NTPPPH overactivity and increased intracellular PPi generation in vitro. These findings support the potential importance of NTPPPH overactivity in PPi generation, both inside and outside the cell, in some subjects with CPPD deposition disease.

Topics: Animals; Calcium Metabolism Disorders; Cells, Cultured; Diphosphates; Fibroblasts; Haplorhini; Humans; Membrane Glycoproteins; Osteoblasts; Phosphodiesterase I; Phosphoric Diester Hydrolases; Pyrophosphatases; Transfection

Cervical Myelopathy is a rare manifestation of calcium pyrophosphate dihydrate (C.P.P.D.) deposition disease. A case is presented where radiographically noncalcified extradural masses containing C.P.P.D. crystals were present at the C7 level, producing cord compression and neurological symptoms. These masses are thought to represent para-articular deposits related to the adjacent facet joints.

Topics: Aged; Aged, 80 and over; Calcium Metabolism Disorders; Calcium Pyrophosphate; Chondrocalcinosis; Diphosphates; Humans; Male; Neck; Spinal Cord Compression; Tomography, X-Ray Computed

Radiographic features of hand and wrist involvement in 26 patients with hemochromatosis and in 26 patients with idiopathic calcium pyrophosphate dihydrate (CPPD) crystal deposition disease were compared. Two radiologists independently examined the radiographs without knowledge of the specific group to which the patient belonged. The results of this study clearly establish that structural joint diseases in the two disorders are not identical. Characteristic findings allow the radiologist to favor one diagnosis over the other. These radiographic differences indicate that the arthropathy of hemochromatosis is related to factors additional to the presence of CPPD crystals, specifically, the more prevalent narrowing of the metacarpophalangeal joint spaces, including those in the fourth and fifth digits, peculiar hook-like osteophytes on the radial aspect of the metacarpal heads, and less prevalent separation of the scaphoid and the lunate.

Topics: Adult; Aged; Calcium Metabolism Disorders; Calcium Pyrophosphate; Diagnosis, Differential; Diphosphates; Female; Hand; Hemochromatosis; Humans; Joint Diseases; Male; Metacarpophalangeal Joint; Middle Aged; Radiography; Wrist Joint

Topics: Animals; Calcium Metabolism Disorders; Calcium Pyrophosphate; Diphosphates; Exostoses; Female; Macaca; Monkey Diseases; Spinal Diseases

Topics: Bursitis; Calcium Metabolism Disorders; Calcium Pyrophosphate; Diphosphates; Female; Humans; Middle Aged

Calcium pyrophosphate dihydrate crystal deposition disease and HA crystal deposition disease are two common disorders that may come to the attention of a physician because of a variety of clinical symptomatology patterns. In CPPD crystal deposition disease, characteristic radiologic features include articular and periarticular calcification and an arthropathy consisting of joint space narrowing, bone sclerosis, often prominent subchondral cyst formation, occasional severe and progressive destructive bone changes, and variable osteophyte formation. These findings are often seen in a characteristic distribution with involvement of non-weight-bearing as well as weight-bearing joints and with involvement of distinctive intraarticular sites such as the patellofemoral compartment of the knee and the radiocarpal compartment of the wrist. In HA crystal deposition disease, characteristic radiologic features consist of calcific tendinitis and periarthritis as well as a more recently described arthropathy. Awareness of the distinctive roentgenographic appearance of these two diseases should allow a specific diagnosis to be made, and an understanding of their pathologic features should aid in appropriate therapy and guide future investigation of possible etiologic factors.

Topics: Aged; Arthrography; Calcification, Physiologic; Calcium Metabolism Disorders; Calcium Pyrophosphate; Crystallization; Diphosphates; Female; Humans; Hydroxyapatites; Joint Diseases; Male; Middle Aged; Prognosis

Topics: Acute Disease; Arthritis; Bruxism; Calcium Metabolism Disorders; Calcium Pyrophosphate; Diphosphates; Humans; Male; Middle Aged; Temporomandibular Joint Disorders; Wrist Joint

Topics: Calcium Metabolism Disorders; Calcium Pyrophosphate; Diphosphates; Joint Diseases