Cheng P T, Pritzker K P
J Rheumatol. 1983 Oct;10(5):769-77.
The relationship between ambient ionic conditions that favor pyrophosphate (PPi) versus phosphate (Pi) biomineralization is important to understanding the pathogenesis of chondrocalcinosis. We studied aqueous solutions at pH 7.4, 37 degrees C, [Na+] = 140 mM, [Mg+ +] = 0.5 mM, [Ca+ +] = 1.0 or 1.5 mM over a range of pyrophosphate and phosphate concentrations to determine the effect of different ambient concentrations and ratios of Pi/PPi on calcium pyrophosphate dihydrate (CPPD) and calcium hydroxyapatite (HA) crystal formation. We found that the Pi/PPi ratio is an extremely important determinant of the crystal product formed. At low [Pi], CPPD crystal formation is partially inhibited by Pi; at higher [Pi], calcium pyrophosphate, calcium phosphate and calcium pyrophosphate-phosphate complexes amorphous to x-ray diffraction are formed; whereas at still higher [Pi], HA crystal formation partially inhibited by PPi. We conclude that CPPD forms when the ratio [Pi]/[PPi] less than 3 and HA forms when [Pi]/[PPi] greater than 100.
有利于焦磷酸（PPi）而非磷酸（Pi）生物矿化的环境离子条件之间的关系对于理解软骨钙质沉着症的发病机制很重要。我们研究了在pH 7.4、37℃、[Na⁺]=140 mM、[Mg²⁺]=0.5 mM、[Ca²⁺]=1.0或1.5 mM的水溶液中，在一系列焦磷酸和磷酸浓度范围内，不同环境浓度和Pi/PPi比例对二水合焦磷酸钙（CPPD）和羟基磷灰石（HA）晶体形成的影响。我们发现Pi/PPi比例是所形成晶体产物的一个极其重要的决定因素。在低[Pi]时，Pi会部分抑制CPPD晶体形成；在较高[Pi]时，会形成焦磷酸钙、磷酸钙和对X射线衍射无定形的焦磷酸 - 磷酸复合物；而在更高[Pi]时，PPi会部分抑制HA晶体形成。我们得出结论，当[Pi]/[PPi]比例小于3时形成CPPD，当[Pi]/[PPi]大于100时形成HA。
