Читать книгу The SAGE Encyclopedia of Stem Cell Research - Группа авторов - Страница 440

Two strategies are presented to diminish an ongoing degenerative process or immunological attack. One is the transplantation of SCs to supply new neurons into the infarcted brain by the activation of intrinsic neural stem cells (NSCs) or delivery of extrinsic SCs such as embryonic stem cells (ESCs) and induce pluripotent stem (iPS) cells–derived neural cells. The second approach is usage of SCs by preparing immunomodulatory and neuroprotective support in a transplanted graft.

The first of these strategies is endogenous (meaning inside the body) repair. The idea behind endogenous repair is to stimulate stem cells that are already present in the brain to heal damaged tissue. The brain has its own store of stem cells. These are “hidden,” as if in reserve. Studies have shown that neural precursor cells (stem cells and their progeny) will proliferate and differentiate into more mature cells in response to growth factors, many of which continue to be tested in rodent models of stroke. Scientists are also looking to mobilize other endogenous stem cells to come out of their hiding places in the body and help with the aftermath of stroke. They have found that the growth factor G-CSF can mobilize hematopoietic stem cells from the bone marrow to enter the bloodstream. From the blood, the cells track to the areas of brain damaged by stroke.

The second strategy is exogenous (meaning outside the body) transplantation, whereby stem cells are harvested, purified, and then partially or completely differentiated prior to being transplanted into patients. The exogenous repair strategy harnesses the power of stem cells from a different angle than the endogenous strategy. Rather than stimulating resident stem cells into action, stem cells are first harvested from patients or donors and then manipulated in the lab prior to being transplanted into a patient. The harvested stem cells can be purified and expanded in number and partially or completely differentiated into progeny of the type required to repair damaged tissue.

A stroke is the loss of brain function due to a disturbance in the blood supply to the brain by either a lack of blood flow caused from a blockage or by hemorrhaging. A stroke was the second most frequent cause of death worldwide in 2011–taking the lives of 6.2 million people. (Blausen Medical Communications)

Many medical researchers believe that stem cell treatments have the potential to change the face of human disease and alleviate suffering. One of regenerative medicine’s greatest goals is to develop new treatments for stroke. Many researches are being conducted around the globe on using stem cells as a therapy for stroke. The following is a review of major researches being conducted at various universities in the United States.