Synovial fluid pyrophosphate and nucleoside triphosphate pyrophosphatase: comparison between normal and diseased and between inflamed and non-inflamed joints.

Abstract

This study provides in vivo data for synovial fluid PPi and NTPase. It suggests that factors other than PPi need to be considered in a study of crystal associated arthropathy. Clinical inflammation, as well as diagnosis, is important in synovial fluid studies.

Interleukin 1 beta suppresses transforming growth factor-induced inorganic pyrophosphate (PPi) production and expression of the PPi-generating enzyme PC-1 in human chondrocytes.

“…This IL-1 effect is related to a reduction of PC-1 rate of transcription and/or mRNA stability. The fact that increased levels of IL-1 are present in rheumatoid arthritis (42) may well account for the decrease in PPi observed in synovial fluids of patients with rheumatoid arthritis as compared with patients with osteoarthritis (43). Based on the results of this study, the functional antagonism of TGF,B and IL-1 may also extend to the regulation of mineralization.…”

Inorganic Pyrophosphate in Metabolic Diseases Predisposing to Calcium Pyrophosphate Dihydrate Crystal Deposition

“…The radiometric assay system employed for PP, estimation is both sensitive and specific (42,43) and contains internal and external controls for potential confounding variables such as hydrolysis of PP, during the incubation phase of analysis. Collection, storage, and treatment of all urine and SF samples was identical, and the differences in values obtained between disease groups and normal subjects is therefore likely to reflect true in vivo differences in PP, concentrations.…”

“…CPPD deposition is largely confined to intraarticular tissues, and local PP, concentrations, particularly in a commonly involved joint (the knee), are therefore of greatest interest. We employed a sensitive and specific radiometric assay (42,43) to estimate PP, levels in synovial fluid (SF) from the knees of patients with untreated metabolic disease and from normal controls. Since SF PP, levels are elevated in knees with established pyrophosphate arthropathy (i.e., structural osteoarthritic changes [4347]), we examined SF from only those subjects with asymptomatic, nonarthritic knees.…”

Dizinc Phosphohydrolase Model Built on a m‐Terphenyl Scaffold and Its Use in Indicator Displacement Assays for Pyrophosphate Under Physiological Conditions

“…This is, however, within the level required for detection of biologically relevant [PP i ] found in synovial fluid (8.6 ϫ 10 -6  to 15.9 ϫ 10 -6 ), which is elevated to higher concentrations in arthritis patients. [28,52] Because clinical methods for measuring synovial [PP i ] rely most commonly on radiological methods and may not readily differentiate phosphate from pyrophophosphate, [28,53] a sensitive fluorescence assay could eventually prove more economical and convenient for some practical applications. Once PP i selectivity was confirmed in the presence of 5 equiv.…”