Simulating arterial wall calcification in vitro: biomimetic crystallization of calcium phosphates under controlled conditions

Summary

Objectives. A method to simulate the biological and pathological crystallization of calcium phosphate in vitro is presented. Background. The pathological crystallization of calcium phosphates during atherosclerosis is still poorly understood as it depends on a variety of external factors, e. g., the presence of biological molecules that act as crystallization promoters or inhibitors. Methods. A computer-controlled double-diffusion device is presented that permits crystallization under constant external conditions (constant pH, constant concentrations of Ca²⁺ and PO₄ ³⁻).Results. The crystallization of hydroxyapatite occurs in a well-defined way. The presence of additives (cholesterol, magnesium) distinctively alters the morphology of the crystals. Conclusions. The simulation of pathological crystallization as in atherosclerosis is possible if the external conditions are kept strictly constant during the experiment. In order to obtain a meaningful insight into biological crystallization, this approach is essential as otherwise the external conditions change continuously during the experiment. The effect of additives can be conveniently studied.