The results of a clinical trial to save volunteers’ leg from amputation by injecting stem cell concentrate to the limb affected by thrombo angitis obliterance (TAO) have been encouraging. The stem cells were taken from the patients’ bone marrow.
The clinical trial is being conducted on patients suffering from blocks in the artery of the leg. Sixty patients were enrolled in the trial, and all of them were smokers. Some had diabetes as well.
Thirty nine of the 44 patients who had already undergone the mandatory 6-month follow-up did not require amputation following stem cell injection to the affected legs. Follow-up of the remaining 16 patients is under way.
The last patient, enrolled on May 25, will complete his six-month follow up in November.
“We have got very good results,” said Dr. K.S. Vijayaragavan. “The legs of 89 per cent of the patients have been saved.” Dr. Vijayaragavan, Head of the Department of Vascular Surgery, Sri Ramachandra University, Chennai, is conducting the trial.
According to him, the failure to save the leg of five patients was because they continued to smoke even after stem cell injection. Immediate and complete cessation of smoking is the most basic and important requirement for saving the leg. Diabetes should also be under control.
Unlike in the case of atherosclerosis caused by cholesterol, blocks seen in legs are caused mainly by nicotine. Nicotine in the blood causes the muscles of the arteries to constrict. It also damages the vessel’s inner lining. The problems get compounded if the patient has diabetes.
While nicotine damages all of the body’s arteries equally, the legs are affected the most. That is because the legs depend on one narrow artery for blood supply and there are fewer smaller vessels branching off from the artery (collaterals).
Tobacco in any form can cause TAO. And TAO very often affects younger people around 40 years of age.
The injection of stem cells would therefore help in creating new collaterals and these would provide the vital conduit for blood flow to the parts of the leg below the block. “The stem cells injected help in angiogenesis,” said Dr. Vijayaragavan.
“We did not see any great difference in angiogenesis between the two groups [one that got stem cell injections very close to the blood vessel, and the second group that got injections close to the vessel and as well as into the main artery above the block],” he said.
Despite the success of the current trial, Dr. Vijayaragavan insists that stem cell injection should be the last option.
“The first line of treatment is a by-pass,” he said. “Angioplasty is not recommended as the first-line treatment. The success rate [of angioplasty] is less than 50 per cent.”
Despite the success seen so far in this trial, more such trials involving more volunteers are necessary before this treatment can be offered as a regular treatment modality.
The Chennai based LifeCell International, a private cord blood bank, is an equity partner at TRICell Stem Cell Centre, which is based at the Sri Ramachandra University, where the trial is being conducted.