Scientists have effectively used human fetal stem cells to treat back leg ischemic ulcers in a model of type 1 diabetes. The culture in which the stem cells had been grown mimicked the wound-healing ability of the cells, suggesting that the active ingredients in the culture could be used instead, avoiding the ethical concerns of using human fetal stem cells.
Chronic wounds and diabetic foot ulcers are serious long-term complications of type 1 diabetes. Ischemia results when the blood supply to a tissue is greatly reduced or stopped, which can occur in diabetes since it can also cause impaired blood flow in patients. The study results open new perspectives for the cure of diabetic ulcers.
The healing activity of stem cells is recognized for their ability to separate into the various component cells of injured tissues, as well as to discharge growth factors that may encourage the formation of new blood vessels in the patient.
Fetal stem cells possess a better ability to multiply and to graft onto host tissue, and to separate into other cell types to replace those in the damaged tissue. The scientists have found that fetal stem cells accelerate the closure of ischemic diabetic ulcers, while stem cells from blood of adult donors are ineffective.
The researchers discovered that a particular type of stem cell, CD133+ cells (derived from human fetal aorta) promoted blood vessel formation in order to salvage the diabetic limb. Three days following the graft consisting of collagen plus CD133+ cells, hardly any CD133+ cells were detected in the ischemic diabetic ulcer, indicating that transplanted cells had done their task in the very first days after transplantation possibly by boosting the generation of new vessels through an indirect mechanism.
This discovery provides a new perspective in the use of fetal stem cells. It is known that wounds heal so well in fetuses that no scar can be visible at birth. It is therefore possible that, when fetal stem cells are transplanted onto diabetic ulcers, they reactivate a fetal program in the recipient to allow those adult ulcers to repair as efficiently as fetal wounds do.
References:
1. P. Madeddu, et al. Human CD133+ progenitor cells promote the healing of diabetic ischemic ulcers by paracrine stimulation of angiogenesis and activation of Wnt signaling. Circ Res. 2009 May 8;104(9):1095-102. PMID: 19342601.
