Scientists who investigated a case of stem cell therapy to treat kidney disease are warning of a new type of complication not seen before, the development of blood vessel and bone marrow masses, the long term effects of which are unknown.

The case involved a woman with severe kidney disease called lupus nephritis who was treated in a private clinic by having stem cells harvested from her own blood injected directly into her kidneys, but then had to have one removed after it developed bleeding. Later analysis revealed a mass of blood vessel and bone marrow cells had developed at the site of injection. The woman died of an infection after her remaining kidney failed.

The scientists who were involved in the removal and analysis of the kidney, were Drs Duangpen Thirabanjasak and Kavirach Tantiwongse from the Departments of Pathology and Surgery at Chulalongkorn University, in Bangkok, Thailand, in consultation with Dr Paul Scott Thorner from the Department of Pathology at The Hospital for Sick Children, the University of Toronto, in Canada and also at Chulalongkorn University. They wrote a paper on their investigation and findings that was published online on 17 June in the Journal of the American Society Nephrology (JASN).

Thirabanjasak, Tantiwongse and Thorner said the treatment the woman received had not worked: instead she developed masses at the sites of injection and hematuria. At first they suspected cancer, but when they removed and examined the kidney they found the masses were angiomyeloproliferative lesions comprising a mixture of blood vessels and bone marrow cells.

Thirabanjasak said in a statement that they had not heard of this type of lesion in patients before:

“We believe that this is either formed directly by the stem cells that were injected or that the stem cells caused these masses to form.”

Also, because this was a unique occurrence, nobody can say how these lesions might have developed over time, she added.

The authors said their findings should be seen as a warning about a new type of complication with stem cell therapy and more research is needed to find out what causes these blood vessel and bone marrow cell masses to grow and find ways to overcome it.

Stem cell therapy has enjoyed an enthusiastic reception because it shows enormous potential to treat and possibly cure a range of diseases. Taking a patient’s own stem cells to grow new tissue to replace that which is damaged or diseased appears in principle to be safe, and researchers are keen to get going with clinical trials to prove it.

Unfortunately, this case appears to highlight what can happen if you try to bypass that stage of scientific scrutiny.

In an accompanying editorial, Drs Andras Nagy, and Susan Quaggin, from Mount Sinai Hospital and the University of Toronto, warn about the growing risk of increasing numbers of private clinics offering stem cell therapies to patients with little or no vetting.

“Premature enthusiasm and protocols that are not fully vetted are dangerous and result in negative publicity for the field of stem cell research, and more importantly, may result in disastrous outcomes with no benefit to the patient,” they wrote.

“Angiomyeloproliferative Lesions Following Autologous Stem Cell Therapy.”
Duangpen Thirabanjasak, Kavirach Tantiwongse, and Paul Scott Thorner.
J Am Soc Nephrol published online 17 June 2010.

Source: American Society of Nephrology.

Written by: Catharine Paddock, PhD