Correlation of changes in circulating bone marrow stem cells in pregnant rabbits after acute myocardial infarction with serum estradiol / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the changes in circulating bone marrow stem cells in pregnant rabbits after AMI (AMI) and their relationship with estradiol.</p><p><b>METHODS</b>Three groups of rabbits were used, namely pregnancy and AMI group, AMI group without pregnancy, and sham operation group with pregnancy. The ratio of CD90(+) cells in the peripheral blood was determined with flow cytometry in all the rabbits, and serum estradiol level measured. Four weeks after AMI, hemodynamic measurements were carried out. The morphological changes of the myocardial tissues were examined with ImageJ 1.31.</p><p><b>RESULTS AND CONCLUSION</b>Four weeks after AMI, the two pregnancy groups showed a higher Left ventricular end systolic pressure(LVESP) and+dp/dtmax, lower left ventricular end-diastolic pressure (LVEDP) and -dp/dtmax and high levels of CD90(+) cells in peripheral blood than AMI group without pregnancy (P<0.01). The ratio of circulating CD90(+) cells increased gradually with gestational age and peaked at the end stage of pregnancy. After delivery the circulating CD90+ cell ratio decreased sharply, showing a significant correlation with serum estradiol level (r=0.725, P<0.01). Four weeks after AMI, the pregnancy group had smaller myocardial infarction (MI) volume than the non-pregnant group (22.17+/-6.34% vs 38.86+/-5.97%, P<0.05). Circulating bone marrow stem cells increased during pregnancy with gestational age and peaked at the end stage of pregnancy. Ten days after delivery, the stem cells resumed basically the normal level. The proportion of circulating bone marrow stem cells was significantly correlated with the level of serum estradiol during pregnancy, and mobilization of the bone marrow stem cells induced by acute ischemic event in pregnant rabbits was advanced. 4 weeks after AMI, the pregnant rabbits showed better heart contraction and diastolic function than the non-pregnant ones.</p>

Migration of intravenously grafted mesenchymal stem cells to injured heart in rats / 生理学报

The present study aimed to determine the role of tissue injury in migration of mesenchymal stem cells (MSCs) intravenously transplanted into heart and to establish experimental basis for improving stem cell therapy in its targeting and effectiveness. MSCs were isolated from bone marrow of male Sprague-Dawley rats and purified by density centrifuge and adhered to the culture plate in vitro. Female rats were divided randomly into four groups. Myocardial ischemia (MI) transplanted group received MSCs infusion through tail vein 3 h after MI and compared with sham-operated group or normal group with MSCs infusion, or control group received culture medium infusion. MI was created in female rats by ligating the left anterior descending coronary artery. The heart was harvested 1 week and 8 weeks after transplantation. The characteristics of migration of MSCs to heart were detected with expression of sry gene of Y chromosome by using fluorescence in situ hybridization (FISH). Ultrastructural changes of the ischemic myocardium of the recipient rats were observed by transmission electron microscope (TEM). One week or 8 weeks after transplantation, sry positive cells were observed in the cardiac tissue in both of MI transplanted group and sham-operated group, the number of sry positive cells being significantly higher in MI transplanted group (P<0.01). No significant difference was found in the number of sry positive cells between 1 week and 8 weeks after transplantation. No sry positive cells were observed in the hearts of control and normal group. In addition, the ultrastructure of some cells located in the peri-infarct area of MI rats with MSCs transplantation was similar to that of MSCs cultured in vitro. These results indicate that MSCs are capable of migrating towards ischemic myocardium in vivo and the fastigium of migration might appear around 1 week after MI. The tissue injury and its degree play an important role in the migration of MSCs.