Dear Editor, We read with great interest, but no real surprise, the letter by Musial and Zwolinska published in a recent issue of your Journal [1]. These authors comment on their findings in dialysis patients suggesting a possible correlation between the levels of MMP-7 (matrilysin) and the severity of cardiovascular complications during end-stage kidney disease and aptly discuss the characteristic of this particular metalloproteinase that may help explain such involvement [1]. The reason why this proposal is not too surprising, at least to us, is that a few years ago, we studied (with microarrays) the genomic profile of primary cell cultures of native and regenerated (after balloon angioplasty) porcine coronary endothelial cells from the same hearts [2]. More recently, we have repeated those studies in pigs fed chronically with diets rich in either cholesterol or x 3 -unsaturated fatty acids [3]. As always in such scientific fishing expeditions, a large number of genes were either up-or down-regulated. However, regenerated endothelial cells expressed the mRNA for two genes that were not found in native cell cultures, MMP-7 and FABP4 [2]. The over-expression persisted in regenerated endothelial cells irrespective of the diet to which the donor animals were subjected [3]. We concluded that the over-expressions of these two genes, MMP7 and FABP4, are major inducing factors of endothelial dysfunction. As our work of the last 25 years implies that endothelial dysfunction is the initial event that permits the inflammatory reactions leading to atherosclerosis [4], we find it easy to accept that an increased level of MMP-7 is a predictor of cardiovascular complications [1].
Paul M. VanhoutteDepartment of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China e-mail: vanhoutt@hku.hk