Howell D S, Muniz O, Pita J C, Enis J E
J Clin Invest. 1975 Dec;56(6):1473-80. doi: 10.1172/JCI108228.
The distribution of calcium pyrophosphate mineral phase, almost exclusively confined to articular cartilage in chondrocalcinosis, and the high level of pyrophosphate (PPi) ion relative to serum in synovial fluid in patients with either chondrocalcinosis or advanced osteoarthritis led to an investigation of whether cartilage cells elaborate PPi ions. Incubates of articular cartilage from young rabbits but not from mature rabbits, as well as growth plates cartilage, released PPi into incubation media during a 4h period. Control rabbit ear cartilage and synovial membrane elaborated negligible amounts of PPi. The PPi was shown to be undialyzable but could be dissociated from the alkaline phosphatase by ultracentrifugation. In 16 patients with osteoarthritis, a substantial output of PPi by samples of articular cartilage from the knee was demonstrated. It is postulated that either rapid cell division and matrix synthesis found in the base of ulcerating osteoarthritic cartilage or remodeling calcified sites are the source of the PPi in such osteoarthritic cartilage. It is further hypothesized that this PPi output accounts at least in part for the elevated PPi levels found in synovial fluid of patients with osteoarthritis.
焦磷酸钙矿物相的分布几乎仅局限于软骨钙质沉着症患者的关节软骨，并且在软骨钙质沉着症或晚期骨关节炎患者的滑液中，焦磷酸（PPi）离子相对于血清的水平较高，这引发了对软骨细胞是否会分泌PPi离子的研究。幼兔而非成年兔的关节软骨以及生长板软骨在4小时的培养期内会向培养基中释放PPi。对照兔耳软骨和滑膜分泌的PPi量可忽略不计。结果表明，PPi不能透过透析膜，但通过超速离心可使其与碱性磷酸酶分离。在16例骨关节炎患者中，证实来自膝关节的关节软骨样本能大量分泌PPi。据推测，在溃疡性骨关节炎软骨底部发现的快速细胞分裂和基质合成，或者钙化部位的重塑，是此类骨关节炎软骨中PPi的来源。进一步推测，这种PPi的分泌至少部分解释了骨关节炎患者滑液中PPi水平升高的原因。
