Morphological and Molecular Analysis of Angiogenesis after Intramyocardial Transplantation of Autologous Bone Marrow Mononuclear Cells

We studied the peculiarities of angiogenesis in the postinfarction period after transmyocardial laser revascularization and intramyocardial implantation of mononuclear bone marrow cells into the pericicatrical zone of the left ventricular myocardium in dogs. Morphological manifestation of angiogenesis in the myocardium after application of laser and cell technologies are angiomatosis, formation of large thin-wall vessels and sinusoids. The angiogenic effect of implanted mononuclear bone marrow cells is determined by high content (43-47%) of CD31⁺ cells in both adherent and nonadherent fractions. More pronounced angiogenic potential of nonadherent cells is determined by intensive expression of cytokine VEGF-B and D mRNA essential for arterial vessels growth. Immunohistochemical studies showed that about 90% cells of the nonadherent fraction are endothelial precursors expressing endothelial cell markers isolectin B₄ and VEGF-R2. It was found that the use of adherent mononuclear bone marrow cells during the postinfarction period induces ossification of the epicardium and subepicardial myocardium layer, formation of cartilage plates, and focal calcification. Implantation of nonadherent mononuclear bone marrow cells into transmyocardial laser channels did not induce ectopic ossification of the myocardium.