Differential Aortic and Mitral Valve Interstitial Cell Mineralization and the Induction of Mineralization by Lysophosphatidylcholine In Vitro.

PURPOSE: Calcific aortic valve disease (CAVD) is a serious condition with vast uncertainty regarding the precise mechanism leading to valve calcification. This study was undertaken to examine the role of the lipid lysophosphatidylcholine (LPC) in a comparison of aortic and mitral valve cellular mineralization.

METHODS

The proportion of LPC in differentially calcified regions of diseased aortic valves was determined using thin layer chromatography (TLC). Next, porcine valvular interstitial cells (pVICs) from the aortic (paVICs) and mitral valve (pmVICs) were cultured with LPC (10-1 - 105 nM) and analyzed for cellular mineralization, alkaline phosphatase activity (ALPa), proliferation, and apoptosis.

RESULTS

TLC showed a higher percentage of LPC in calcified regions of tissue compared to non-calcified regions. In pVIC cultures, with the exception of 105 nM LPC, increasing concentrations of LPC led to an increase in phosphate mineralization. Increased levels of calcium content were exhibited at 104 nm LPC application compared to baseline controls. Compared to pmVIC cultures, paVIC cultures had greater total phosphate mineralization, ALPa, calcium content, and apoptosis, under both a baseline control and LPC-treated conditions.

CONCLUSIONS

This study showed that LPC has the capacity to promote pVIC calcification. Also, paVICs have a greater propensity for mineralization than pmVICs. LPC may be a key factor in the transition of the aortic valve from a healthy to diseased state. In addition, there are intrinsic differences that exist between VICs from different valves that may play a key role in heart valve pathology.