SAN FRANCISCO — Chronic wounds due to scleroderma responded well to a combination of mesenchymal stem cells and bilayer bioengineered skin, in a study of 12 patients followed for up to 6 months.
Four wounds completely healed, and the others decreased in size enough that patients' quality of life was improved, Dr. Vincent Falanga said in a press briefing at the annual meeting of the American Academy of Dermatology.
He and his associates harvested the patients' own stem cells from a small amount of bone marrow taken from the hip. And they applied the stem cells to the wound with an innovative fibrin spray system that had not been used before in humans.
Using a pressurized double-barrel syringe, they placed the cells in fibrinogen in one barrel and in a thrombin solution in the other. This produced a fine spray, spreading the cells evenly over the wound and simultaneously combining the fibrinogen and thrombin to form fibrin, which glued the cells to the exposed wound tissue, said Dr. Falanga of Boston University and Roger Williams Medical Center, Providence, R.I.
In prior studies, Dr. Falanga determined that the spray alone would not be enough to encourage the stem cells to differentiate into skin cells. To teach the stem cells to become skin cells, he covered the spray with living bioengineered skin substitute, specifically a product from Organogenesis Inc. called Apligraf that contains two layers of living cells, one of fibroblasts and one of keratinocytes.
Dr. Falanga gave each patient three treatments, the maximum permitted by the Food and Drug Administration. He said that he thinks the patients would do even better with additional treatments and hopes to receive approval for this as his studies continue.
Dr. Falanga said he found it necessary to use quite a large number of stem cells, 1.5 million to 2 million/cm
He continued, “I think that this is a lesson that's going to be learned when we go into other areas of medicine. Whether it's skin, brain, spinal cord, we have to have some methods whereby we impart upon the stem cells a didactic component, a direction we want them to go to.”
Dr. Falanga disclosed that he is a former consultant to the company Organogenesis.