One of the most life-threatening forms of stroke is intracerebral hemorrhage (ICH). This type of stroke is caused by bleeding that occurs within the brain tissue. Common causes of brain hemorrhage include brain tumors, brain trauma, and aneurysms. Effective treatment for patients suffering from intracerebral hemorrhage is lacking. The usefulness of various cell types to treat the effects of ICH continues to be studied. Bone marrow mononuclear cells are considered prime candidates for cell therapy for patients with ICH because they can be quickly collected and processed from bone marrow.
CD34 is a glycoprotein located in cell membranes, and was initially found to be present in hematopoietic stem and progenitor cells. CD34 is a commonly used marker for stem cells; however, there have been some experiments in the past that questioned whether CD34 is in fact a marker for these cells because some progenitor cells do not have CD34 (CD34‒), yet can produce CD34+ stem cells. Studies over the years show that CD34+ cells provide the hematopoietic activity (blood cell formation) in bone marrow and the development of specialized blood cells types (differentiation). Transplantation of patients with bone marrow that has a higher concentration of CD34+ cells is associated with faster engraftment (growth of healthy blood stem cells) and less related complications.
The concept of stem cell therapies has existed for decades including the transplantation of bone marrow stem cells for patients with multiple myeloma and leukemia. However, controversy has arisen and persists in regards to the use of stem cells from human embryos. Due to the debates and ethical concerns with the use of human embryonic stem cells, new research is uncovering possible alternatives, such as induced pluripotent stem cells (stimulation of a patient’s own cells to behave as embryonic stem cells).