Diastolic flow, which relates to the relaxation or filling phase of the heart cycle, occurs during the relaxation phase after myocardial contraction, with an abrupt increase above systolic levels and a gradual decline parallel with that of aortic diastolic pressures. In vasculogenesis, circulating endothelial progenitor cells (EPC) contribute to new blood vessel growth (capillaries) by secreting the necessary growth factors and chemokines for endothelial cells to migrate or by incorporating into the newly formed vessels. Systolic flow, which relates to the contraction or pumping phase of the heart cycle, has rapid, brief, retrograde responses. Yin et al., Blood 90: 5002-5012 (1997); Miaglia, S. CD34 cells isolated from human blood may be capable of differentiating into cardiomyocytes, endothelial cells, and smooth muscle cells in vivo. CD34 cells represent approximately 1% of bone marrow derived nucleated cells; CD34 antigen also is expressed by immature endothelial cell precursors (mature endothelial cells do not express CD34). Techniques have been developed using immunomagnetic bead separation to isolate a highly purified and viable population of CD34 cells from bone narrow mononuclear cells. Angiogenesis is the formation of new capillaries by sprouting from the existing capillary net, probably from the postcapillary venules; arteriogenesis is the transformation of preexisting aterioles/collaterales into small muscular arteries and/or de novo formation of new vessels with a tunica media; and vasculogenesis is the formation of new vessels from multipotent endothelial stem cells. 10, 2009), which is a divisional application of application Ser. Coronary Blood Flow The flow of blood through the coronary arteries is pulsatile, with characteristic phasic systolic and diastolic flow components. CD34 is a hematopoietic stem cell antigen selectively expressed on hematopoietic stem and progenitor cells derived from human bone marrow, blood and fetal liver. Stromal cells do not express CD34 and are therefore termed CD34−. In vitro, CD34 cells derived from adult bone marrow give rise to a majority of the granulocyte/macrophage progenitor cells (CFU-GM), some colony-forming units-mixed (CFU-Mix) and a minor population of primitive erythroid progenitor cells (burst forming units, erythrocytes or BFU-E). CD34 cells also may have the potential to differentiate into, or to contribute to, the development of new myocardial muscle, albeit at low frequency. Neovascularization can be divided into three processes: angiogenesis, vasculogenesis, and arteriogenesis. The cardiac cycle is coordinated by a series of electrical impulses that are produced by specialized heart cells found within the sino-atrial node and the atrioventricular node. Since the mononuclear fraction of bone marrow contains stromal cells, hematopoietic precursors, and endothelial precursors, the relative contribution of each of these populations to the observed effects, if any, remains unknown. Two clinical studies support the clinical application of bone marrow derived CD34 cells after myocardial infarction. Stamm, et al., Lancet 361: 45-46 (2003); Herenstein, B. The creation of new blood vessels is dependent on a complicated interaction between locally produced cytokines and cells derived from the tissue area, and blood circulation.
Each of these applications is incorporated herein by reference in their entirety.
Blood pressure increases and decreases throughout the cardiac cycle.
The Cardiac Cycle The term “cardiac cycle” is used to refer to all or any of the mechanical events related to the coronary blood flow or blood pressure that occurs from the beginning of one heartbeat to the beginning of the next.
It can also accelerate reendothelialization, attenuate intimal hyperplasia in balloon-injured carotid artery. Binding of FGF-1 or FGF-2 to heparan sulphates enhances their autocrine or paracrine bioactivity.
FGF-receptors originate from the super-family of immunoglobulins, with 4 types identified: FGF-R1, R2, R3, and R.