The Effect Of Autologous Stem Cell Mobilization Induced By Granulocyte Colony Stimulating Factor On Acute Myocardial Infarction

In recently years, coronary heart disease becomes a major cause of morbidity and mortality. Despite significant advanced in medical therapy and interventional therapies such as coronary artery bypass grafting and percutaneous coronary intervention, no therapies are currently available to restore dead myocardium. Recent experimental studies and clinical trials suggested stem cells might contribute to the regeneration of infarct myocardium and enhance neovascularization of ischemic myocardium, improve the heart function and prevent the remodeling of left ventricle.Granulocyte colony-stimulating factor (G-CSF), induces the mobilization of hematopoietic stem cell and endothelial progenitor cells from bone marrow into the peripheral blood circulation. In addition, G-CSF activates various signaling pathways such as Akt, extracellular signal-regulated kinase, and Janus kinase 2/signal transducer and activator of transcription 3 through G-CSF receptors in cardiac myocytes. cytokine-mediated recruitment of BMSCs has been reported to improve cardiac dysfunction and reduce mortality after AMI. However, because of many studies related to G-CSF are limited to the role and mechanism of the heart, there are rarely reported the role and mechanism to the blood vessels, particularly the chronic arterial occlusive diseases which are closely related to the ischemic heart disease such as thrombosis and atherosclerosis, etc. In addition, the direct effect of G-CSF mobilization is leukocytosis, which caused hyper viscosity and had a greater impact on blood coagulation/anti-coagulation system, which may lead to hypercoagulability. There is not yet clear if it can induce the deterioration of arterial occlusive disease. Much recent researches have shown that, as one of stem cells, endothelial progenitor cells (EPCs) exist in bone marrow, peripheral blood and cord blood. The EPCs can be recruited to the local vascular injury, differentiated into mature endothelial cells and involved in angiogenesis and repair by stimulated with injury signals. There are various means to increase the number of EPCs in peripheral blood including exercise, drugs to stimulate, etc. The drugs which can increase EPCs in adult peripheral blood include stem cell factor, granulocyte colony-stimulating factor, statins, estrogen and so on confirmed by the currently researches. As an exogenous stem cell mobilization agent, G-CSF can stimulate EPCs from bone marrow into the peripheral blood and accelerate re-endothelialization of the injury vascular. Combination of well-known adverse reactions, we infer that G-CSF can be bound to have repair effects and even side effects on the local blood vessels, including chronic obstructive pulmonary arterial lesions and arterial system itself.The research was divided into two parts; first, a new type of chronic arterial occlusive disease model was set up, and then combined with relatively mature rabbit atherosclerosis model, analysis of the effects of G-CSF on the partial form and function in chronic obstructive arterial. And then, a prospective, randomized, double-blined clinical trial to investigate the safety and effect of autologous peripheral blood stem cells mobilization by intravenous injection of granulocyte colony stimulating factor (G-CSF) in patients with ST-elevation acute myocardial infarction (AMI).Part I The impact of G-CSF on Chronic Obstructive ArteryObjective:to investigate the impact of G-CSF on artery endothelial cells in arteriosclerosis and analyze its systematic impact on chronic obstructive artery systems like arteriosclerosis from functional and morphological aspects, with the hope of providing a guidance for a better application and prevention of adverse effects in clinical practice. Methods:30 healthy experimental New Zealand white rabbits were randomly divided into the control group (n=6), the normal feeding group (n=6), normal feeding +CSF group (n=8), the high fat feeding group (n=8), the high fat feeding +G-CSF group (n=8). G-CSF was injected subcutaneously at a dose of 15ug/kg diluted to 0.5mL with normal sodium for a consecutive 5 days,4 times in all once every other week. Blood sampling was collected once a week. Common carotid artery matrix was analyzed by immunohistochemical test. Results:8 rabbits died during experiment. There finally exited 5,6,5,6 animals in the four groups, respectively. Blood lipid dynamic test found an elevated blood lipid like TC and LDL in the high fat feeding group, reaching peak 6 weeks later (P<0.05), stable 8 weeks later. The application of G-CSF shifted forward the peak of blood lipid such as TC and LDL by 2 weeks (P<0.05 compared with the control group), presenting double hump, with no influence on TG. Shrinked internal diameter, slowed bloodstream, and increased resistance index of the proximal end of common carotid artery was observed using carotid artery ultrasound 3 weeks after operation (P<0.05). Stenosis appeared more dramatic in high fat feeding rabbits after the application of G-CSF (from 53.24±0.7% to 59.51±0.5%, P<0.05). Vessels were consecutively clogged until completely occlusion 5 weeks after, with a more dramatic change in arteriosclerosis vessels confirmed by the ultrasound. While it took about 7 weeks for complete occlusion of the vessel in normal feeding rabbit, it was 2 weeks shorter in the G-CSF group. Collagen staining in thoracic aorta suggested that G-CSF induced production of matrix. Increased positive rate of MMP-9 and TIMP-2 were confirmed by immunohistochemical test (1.08±0.06%,26.31±1.08%,27.90±1.07%,45.51±1.60%, 4.07±1.01%,36.08±1.68%,71.36±3.01%,67.26±2.54%, respectively in the four groups)。Conclusions:G-CSF deteriorated arteriosclerosis presenting as expensed plaque, thickened tunica intima mainly through impacting TC and LDL, not TG, possibly related to its impact on matrix. Model of arteriosclerosis was successfully established in the high fat feeding group, displaying impaired endothelial function especially in large arteries, and a corresponding endothelial function. G-CSF impacted the artery system. The impact was more significant in larger arteries. There were relationships in appearance and function between normal and arteriosclerosis endothelial cells, as well as in their reactions to G-CSF.Part 2 The clinical study of intravenous injection of granulocyte colony stimulating factor for mobilization of autologous peripheral blood stem cells to treat patients with acute myocardial infarctionChapter 1 The evaluation of safety of intravenous injection of granulocyte colony stimulating factor for mobilization of autologous peripheral blood stem cells in patients with acute myocardial infarctionObjective:To investigate the safety of autologous peripheral blood stem cells mobilization by intravenous injection of granulocyte colony stimulating factor (G-CSF) in patients with ST-elevation acute myocardial infarction (AMI). Methods: Fifty patients with AMI were received intravenous injection of G-CSF (10μg/kg/d) for 5 days after successfully treated with primary percutaneous coronary intervention (PCI). During the period of treatment, attention was paid to the following side effects: bone pain, fever, gastrointestinal effects (nausea, vomit, coprostatis), deterioration of angina or heart failure, reinfarction and restenosis in stent). Results:The incidence of complications during G-CSF treatment was 32%, including that of bone pain being of 10%, low fever being of 12%, high fever being 8%, angina being of 2%. Conclusion: In patients with AMI, intravenous injection of G-CSF to mobilize autologous peripheral blood stem cells is feasible and safe.chapter 2The effect of autologous peripheral blood stem cells mobilization by intravenous injection of granulocyte-colony stimulating factor on left ventricular function in patients with acute myocardial infarctionObjective:To evaluate the effect of autologous peripheral blood stem cells mobilization by intravenous injection of granulocyte colony stimulating factor (G-CSF) on left ventricular function after acute myocardial infarction (AMI).Methods:One hundred patients(93 males, average age,58.71±7.57years) with ST-elevation AMI were included after successful emergent percutaneous coronary stent intervention (PCI)<12hours after symptom onset.Patients were randomly divided into 2 groups:G-CSF treated groups, which were injected with G-CSF (10μg/kg/d) for 5 days after the PCI and control group, which were injected with placebo. CMR and echocardiography was conducted twice at 1 week and 6 months after AMI. Results:the left ventricular ejection fraction (LVEF) in G-CSF group improved prominently than in the control group measured by both MRI(47.5±11.8% to 52.2±9.9% vs49.1±8.4% to50.5±9.9%)and echocardiography(59.7±9.2%to 63.9±7.7%vs57.3±9%to59.1±9.6%). The absolute value of increases in LVEF was significantly higher in G-CSF treated group than in control group (p<0.05). Conclusions:Bone marrow stem cell mobilization with injection intravenous G-CSF significantly improved ventricular function after acute myocardial infarction compared with the recovery observed in the placebo group. CMR may be used as an essential tool to evaluate cardiac functions.