Ch. Schick et Po. Schwille, STUDIES ON THE REDUCTION OF AORTIC CALCIFICATION BY ALKALI CITRATES IN AN EX-VIVO TISSUE-PREPARATION IN THE RAT, Arzneimittel-Forschung, 43-2(8), 1993, pp. 831-835
The effect of orally administered alkali citrates on the calcification
of arterial vessel was studied in the rat. Freshly dissected aortic s
egments were placed in Millipore diffusion chambers and grafted intrap
eritoneally. Within 21 days calcification of the media had developed.
Under treatment with 2.1 mmol citrate per animal and day a significant
decrease in histologically detectable calcification areas occurred, a
s assessed by greatest thickness and longitudinal expansion. This effe
ct was more pronounced with potassium citrate and potassium sodium cit
rate, and less marked with sodium citrate. The calcium and phosphorus
content of aortic tissue remained unchanged, but magnesium increased s
ignificantly. The spheroid particles deposited in the media were chara
cterized in more detail by electron microscopy and elemental microanal
ysis, X-ray diffraction, and determination of the molar calcium-phosph
orus ratio. The combined data suggest that in the model selected for s
tudying biocalcification not mature hydroxyapatite but some precursor
of this substance is deposited, and that in animals receiving alkali c
itrate treatment deposition of amorphous calcium phosphate is likely.
It is concluded that in the ex vivo aortic wall preparation oral alkal
i citrates a) bring about a reduction in calcification areas in the me
dia layer b) impair the maturation of hydroxyapatite and its depositio
n in the arterial tissue; c) promote the accumulation of magnesium. Wh
ether these results are of significance for the calcification of arter
ies in situ and treatment regimens is unknown.