EXTRACELLULAR PYROPHOSPHATE METABOLISM OF CHONDROCYTES

最近相当多的研究显示关节内异常高 无机焦磷酸盐(PPI)作为重要代谢产物的生产 二水焦磷酸钙(CPPD)沉积症缺陷及 骨性关节炎。软骨已被确定为可能的主要来源 在这些疾病中PPI异常产生的可能性。购买力平价指数的上升 产生胞外酶，核苷三磷酸焦磷水解酶 (NTPPPH)在关节软骨和滑液中均有表达。 有CPPD的证据。SF NTPPPH活性与SF PPI相关 在各种关节疾病中有浓集，但目前尚不清楚NTPPPH 参与关节内PPI的制作。 初步实验表明分离的猪软骨细胞表现出 ECTO-NTPPPH活性和自发合成的PPI。我们有部分 从分离的软骨细胞脱氧胆酸提取物中纯化NTPPPH 阴离子交换层析。我们建议如何高度提纯猪 软骨细胞NTPPPH亲和层析及抗血清的制备 兔子。沉淀的抗血清将使免疫组织学 NTPPPH在关节组织中的分布测定如果一种抗血清 特异性阻断NTPPPH活性的基因，我们希望能确定 如果完整的软骨细胞胞外PPI的形成依赖于 NTPPPH。

Considerable recent research has revealed abnormally high intra-articular production of inorganic pyrophosphate (PPi) as an important metabolic defect in calcium pyrophosphate dihydrate (CPPD) deposition disease and osteoarthritis. Cartilage has been identified as a probable major source of abnormal PPi production in these diseses. Elevated activity of the PPi generating ecto-enzyme, nucleoside triphosphate pyrophosphohydrolase (NTPPPH) is found in both cartilage and synovial fluid (SF) of patients with CPPD deposition. SF NTPPPH activity correlates with SF PPi concentration in a variety of arthropathies, but it is not known if NTPPPH participates in intra-articular PPi production. Preliminary experiments indicate isolated porcine chondrocytes exhibit ecto-NTPPPH activity and spontaneously elaborate PPi. We have partially purified NTPPPH from deoxycholate extracts of isolated chondrocytes by anion exchange chromatography. We how propose to highly purify porcine chondrocyte NTPPPH by affinity chromatography and prepare antisera in rabbits. A precipitating antiserum would allow immunohistologic determination of NTPPPH distribution in articular tissues. If an antiserum which specifically blocks NTPPPH activity is obtained, we hope to determine if extracellular PPi elaboration by intact chondrocytes is dependent on NTPPPH.