Scientists in South Korea transplanted mesenchymal stromal cells (MSCs) derived from human amniotic membranes of the placenta (AMSCs) into laboratory mice modeled with oxygen-induced retinopathy. The treatment aimed at suppressing abnormal angiogenesis, which is recognized as the cause of many eye diseases, such as diabetic retinopathy and age-related macular degeneration.
The researchers reported that the AMSCs successfully migrated to the retinas of the test animals and, because of the growth factors secreted by the cells, were able to suppress retinal neovascularization. Their study (“Retinal angiogenesis effects of TGF-ß1, and paracrine factors secreted from human placental stem cells in response to a pathological environment”) is freely available on-line as an unedited early e-pub of Cell Transplantation.
The benefit of using MSCs in stem cell therapy is their ability to self-renew and differentiate into a variety of specialized cell types, such as osteoblasts, chondrocytes, adipocytes, myocardiocytes, and neuron-like cells. In addition, it has been shown that MSCs have the ability to modulate the immune response and reduce local inflammation. They can be isolated from a variety of sources, such as adipose tissues, tendons, peripheral blood, umbilical cord blood, human placenta, and bone marrow.
MSCs have been successfully transplanted in a number of disease models for which they have been shown to offer therapeutic benefits. MSCs isolated from human placenta, however, may be richer in growth factors than those derived from other sources because of their essential role in fetal development, said the researchers.
According to the scientists, AMSCs secrete higher levels of certain growth factors (such as transforming growth factor beta, TGF-β, and cytokines) than MSCs derived from other sources, such as fat or bone. The beneficial growth factors secreted by the placenta-derived stem cells included vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF), the latter, a well-known natural inhibitor of angiogenesis.
They also cited the abundance of placental tissues over other sources, and the greater ease of MSC isolation from these growth factor-rich tissues as another benefit for their therapeutic use.
“Placenta-derived MSCs have powerful immunomodulatory functions,” said study co-author Jisook Moon, M.D., department of applied bioscience and department of engineering, CHA University, Seoul, Korea. “In our study the AMSCs were administered via intraperitoneal injection. Detection of the transplanted cells in the retina illustrated their ability to migrate from the site of injection to the injured tissue. The blood brain barrier restricts the permeation of molecules and cells through the circulatory system into the central nervous system. Confirming that AMSCs were able to traverse the BBB was crucial in elucidating whether or not these cells are viable candidates for treatment of retinopathy.
The researchers concluded that although further studies are needed to confirm the effect of AMSCs on neovascular diseases, the data collected in their study provided insights into the mechanisms by which these cells exert their therapeutic effects.
The scientists believe that their technique may advance stem cell therapy toward clinical practice and offer novel therapies for eye diseases in people.