Intramyocardial implantation of autologous bone marrow-derived stem cells combined with coronary artery bypass grafting in patients with ischemic cardiomyopathy: a pilot study.

BACKGROUND: Ischemic cardiomyopathy has the distinctiveness of irreversible myocardial damage with scar tissue formation and mainly impaired perfusion of the remaining viable myocardium. We present results of the first series of patients with severe ischemic cardiomyopathy managed in our institution with intramyocardial implantation of autologous bone marrow stem cells at the time of coronary artery bypass grafting. The aim is to evaluate feasibility and safety of the procedure in our institution. PATIENTS AND METHODS: Nine patients with severe ischemic cardiomyopathy scheduled for elective coronary artery bypass grafting were managed with concurrent intramyocardial autologous bone marrow stem cells injection in pre-defined viable peri-infarct areas that showed poor perfusion and could not be grafted. Detailed mapping of infracted and hibernating myocardial segments was performed in all patients with single photon emission computed tomography segmental analysis. RESULTS: There was no perioperative 30-day mortality. Improvement was evident in left ventricular ejection fraction which was increased significantly from 31.3% preoperatively to 42.4%, 46.6% and 52.5% at 3, 6 and 12 months respectively. Postoperative thallium scintigraphy revealed increased perfusion in myocardial segments corresponding to areas of stem cell injection and a net reduction in the estimated infarct size at 6 and 12 months in 5/8 (62.5%) patients. CONCLUSIONS: Preliminary data from this pilot study show that intramyocardial administration of bone marrow stem cells in patients undergoing coronary bypass grafting for ischemic cardiomyopathy is safe and associated with an improvement in left ventricular function and enhanced reperfusion of non-viable myocardial territories.

Cardiomyogenic potential of human adult bone marrow mesenchymal stem cells in vitro.

BACKGROUND: The aim of this study was to investigate the ability of adult human bone marrow mesenchymal stem cells to differentiate towards a cardiomyogenic phenotype IN VITRO. METHODS: Bone marrow samples were aspirated from 30 patients undergoing open heart surgery from the anterior iliac crest. Second passaged cells were treated with 10 microM 5-azacytidine. As control groups we used cells not expanded in culture and cells untreated with 5-azacytidine. Morphologic characteristics were analysed by confocal and electron microscopy. The expression of the cytoskeletal protein vimentin and muscle-specific myocin heavy chain was analysed by immunohistochemistry. The expression of the cardiomyocyte specific genes alpha-cardiac actin, beta-myocin heavy chain and cardiac troponin-T was detected by reverse transcriptase polymerase chain reaction. RESULTS: Mesenchymal stem cells were spindle-shaped with irregular processes. Cells treated with 5-azacytidine assumed a stick-like morphology. They connected with adjoining cells to form myotube-like structures. Numerous myofilaments were detected in induced cells which were immunohistochemically positive for myosin heavy chain and vimentin. The mRNAs of all specific cardiac genes were expressed in both induced and uninduced cells. CONCLUSION: These results indicate that adult human bone marrow mesenchymal stem cells treated with 5-aza can differentiate towards a cardiomyogenic lineage IN VITRO.

Disruption of the small-intestine mucosal barrier after intestinal occlusion: a study with light and electron microscopy.

It is known that the gut may serve as a reservoir for various microorganisms, which under specific circumstances may intrude into the systemic circulation, causing systemic infections. The aim of the present study was to estimate the "critical time" of disruption of the small-intestine mucosal barrier in conditions of experimentally induced intestinal occlusion, based on the histopathological alterations observed under light and electron microscopy. Forty rabbits underwent small-intestine obstruction through ligation with a nonabsorbable suture. Blood cultures from portal vein and inferior vena cava, as well as cultures from the peritoneal fluid, a hepatic fragment, and a mesenteric lymph node, were obtained before the ligation (0 h). The same cultures were repeated at 4 and 8 h (group A, 20 rabbits) and at 6 and 12 h after the ligation (group B, 20 rabbits). Small-intestine specimens proximal to the occlusion were taken for examination under the optic and electronic microscope in the same time intervals. Five of 20 rabbits of group A died within 4 h and 6 of 20 rabbits of group B died within 6 h after the operation. All anaerobic cultures were negative. All aerobic cultures that became positive developed Escherichia coli colonies. Intestinal epithelium of dead animals was transformed to cuboid with destruction of goblet cells and alteration in secretion of acid polysaccharides. The mucosal appearance of all rabbits that survived 12 hours after ligation was the same. The disruption of the mucosal barrier begins 4 h after complete intestinal occlusion. At 12 h after complete intestinal occlusion, the disruption is total with different degrees of severity.

[Ultrastructural study of the distal convoluted tubule in the mouse embryo]. / Etude ultrastructurale du tube contourné distal chez l'embryon de souris.

This work constitutes a contribution to the ultrastructural study of the differentiation of the epithelium of the distal convoluted tubule, which has been poorly investigated. The study was realised on mouse embryos B1 C57 (14th, 16th, 18th and 20th day of gestation), on newborn and one month old mice. On day-16 the distal convoluted tubule was evident in the form of a cellular mass; the lumen appeared on day-18. On day-20, completely differentiated epithelial cells were observed in some distal tubules; those cells showed cytoplasmic processes in the apical part, and basilar plasma membrane invaginations, containing mitochondria with numerous cristae. The results of this ultrastructural study confirmed that the differentiation of renal epithelium is progressive and indicates the installation of the renal function before birth.