Treating with Transplants

Cell Therapy in Chagas Disease

Antonio C. Campos de Carvalho, Regina C. S. Goldenberg, Linda A. Jelicks,Milena B. P. Soares, Ricardo Ribeiro dos Santos, David C. Spray, and Herbert B. Tanowitz

May 2009

Interdisciplinary Perspectives on Infectious Diseases

Chagas disease, which is caused by the parasite Trypanosoma cruzi, can lead to cardiomyopathy and eventually to congestive heart failure. This is a large problem because the disease is endemic in all Latin American countries except for those in the Caribbean, and there are no effective treatments currently available. According to the article, 16–18 million individuals are infected with the parasite and this number continues to grow as more and more people are infected yearly. It is estimated that 10%–30% of all infected individuals will acquire chronic chagasic cardiomyopathy, which means that there are anywhere between 1.6 to 5.4 million patients with chronic chagasic cardiomyopathy in Latin America. Because of this, Chagas disease is one of the most important causes of heart disease in this region.

In the past heart transplants have been attempted as a cure for the disease but this procedure comes with many problems. The latest move has been to try to cure the disease by replacing the damaged heart cells with bone-marrow derived cells – experiments in mice have shown that that the transplantation of bone-marrow-derived cells ameliorates the inflammation and fibrosis in the heart caused by the Chagas infection.

In the most recent notable experiment, investigators in Brazil “initiated a clinical trial to examine the feasibility and safety of autologous bone marrow cell transplantation in patients with congestive heart failure due to chronic chagasic cardiomyopathy.” These patients have a 40% mortality rate within the first 2 years of onset. The study was only conducted on people who were at the stage of the infection where their only option is a heart transplant. Bone marrow aspiration was performed on the day of the injection and then the cell suspension was injected into the coronary arteries. This trial was not meant to show efficacy but it did show that, in general, this kind of therapy is feasible and safe. Furthermore, they had positive results such as a significant improvement in a 6 minute walking test as well as an improvement in quality of life. Furthermore, there was no detectable increase in arrhythmias. Because of the positive outcomes of this first trial, they are currently working on a phase II trial to test for efficacy which will be larger randomized, double-blind and placebo controlled trial.

It is very possible that this will be an effective therapy for patients with end-stage chagasic heart disease. However, we still have a long way to go. In addition to proving efficacy, researchers still do not know which cell type(s) is/are responsible for the effects observed in the animal and the preliminary human experiments. This will be important for further improving the therapy. My personal worry is that because this disease is generally concentrated in poorer populations, the people who need it most will not benefit from these scientific breakthroughs. It seems unlikely to me that this type of treatment will ever be an inexpensive or easy procedure, which means that it may be impossible to deliver in poor, remote areas, rendering it useless for many of the people who need it.

http://www.hindawi.com/journals/ipid/2009/484358.html