Mesenchymal stem cells from umbilical cord have the ability to differentiate into cartilage cells, fat cells, bone cells, and blood vessels cells. These cells also are poorly recognized by the immune system of the patient and are at a low risk of being rejected by the patient’s immune system.
Valeria Aguilera and her colleagues from the laboratory of Claudio AguayoWe at the University of Concepción, Chilee have evaluated the use of mesenchymal stem cells from umbilical cord in the formation of new blood vessels in damaged tissues. Wharton’s jelly mesenchymal stem cells of hWMSCs were used to potentially accelerate tissue repair in living animals.
Aguilera and her co-workers began by isolating mesenchymal stem cells from human Wharton’s jelly (a connective tissue in umbilical cord). Then they grew these cells in culture for 14 or 30 days. Interestingly, the longer the WMSCs grew in culture, the more they looked like blood vessel cells. They began to express blood vessel-specific genes and proteins. WMSCs cultured for 30 days were even more like blood vessels than those grown in culture for 14 days.
When these cells were injected in the mice with damaged skin, the results showed that the WMSCs cultured for 30 days significantly accelerated wound healing compared with animals injected with either undifferentiated hWMSCs or with no cells.
The wounds of mice treated with the WMSCs cultured for 30 days looked healthier, but they had many more blood vessels.
When laboratory animals received the culture medium from the WMSCs cultured for 30-days also showed significant acceleration of their healing, which suggests that these cells secrete a host of healing molecules that induced the formation of new blood vessels. One might also conclude that the implanted WMSCs did not contribute to the formation of new blood vessels, but simply directed the formation of new blood vessels by secreting healing molecules. However, when WMSCs were detected in the healed tissue, they were predominantly found in the walls of new blood vessels.
These results, which were published in PLOS ONE, demonstrate that mesenchymal stem cells isolated from umbilical cord connective tissue or Wharton’s jelly can be successfully grown in culture in the laboratory and trans-differentiated into blood vessels-forming cells (endothelial cells). These differentiated hWMSC-derived endothelial cells seem to promote the formation of new networks of blood vessels, which augments tissue repair in laboratory animals through the secretion of soluble pro-blood vessel-making molecules and, occasionally, by contributing to the formation of new vessels, themselves.