Stem Cell Transplants in Monkeys: Do they work?

According to a study done conducted by, implanted stem cells can regenerate cells of a damaged heart in macaque monkeys. According to, the new cells are not rejected instantly like other foreign cells entering the body, and they helped the heart contract after an intentional heart attack. During and after this heart attack the new stem cells integrated with the existing heart cells, and there were no signs of rejection coming from the immune system.  However, the monkey who received these new stem cells did suffer from an irregular heartbeat for the following four weeks after the implantation of the stem cells.

iPS cells were generated from MHC homozygous monkey and differentiated into cardiomyocytes. The cardiomyocytes were transplanted into another monkey in which either of the MHC haplotypes was identical to the donor. Credit: Yuji Shiba

Diagram of how Yuji Shiba, a human biology professor in Japan, conducted this experiment (Yuji Shiba)

The leader of the study was Yuji Shiba, a human biology professor at Shinsu University in Japan. In an interview with, Shiba said that these findings can be used to help cure patients with chronic heart infarctions. Before the integration of stem cells, oxygen was blocked from entering the monkey’s heart for three hours, giving the monkey myocardial infarction, or MI. After oxygen was allowed to re-enter the hear the monkey suffered from reperfusion, yet the study found that the stem cell implantation only helped cure MI. In order to avoid an immune response/rejection to the new stem cells, Shiba gave the monkey daily dosages of immunosuppressant drugs prior to the oxygen blockage, and he ensured that a surface protein, MHC, was carefully matched between the donor & recipient monkeys. Shiba predicts that cell implantations like the ones he ran on the monkeys, which have been used in humans before, will become more widely used within humans sooner rather than later.

Heart disease is one of the leading causes of death in humans right now, so the findings of Shiba’s study are extremely helpful towards fighting heart disease. Fortunately, post-experiment meta-analyses found that the p-value of the study was less than 0.05, which means that it is unlikely that the monkey’s condition improved after the stem cell implantation solely due to chance. Several of these meta-analyses were done after the experiment was finished, with tests such as a two-sided Fisher’s Exact Test and Turkey’s multiple comparison test being conducted. All of these tests found the low p-value, which is an encouraging find in terms of finding the cure to heart disease.

Image result for heart disease

Heart disease death rates in the United States from 2008-2010 (

As I said before, heart disease is one of the leading causes of death in human health today. According to, heart disease ranked 2nd in Canada in 2011, responsible for 19.7% of all deaths in the country that year. Only cancer (29.9% of all deaths) killed more people that year. The amount of people killed by heart disease every year is obviously alarming, so any strides made towards finding a way to cure and treat heart diseases are encouraging and beneficial to human health.

Leave a Reply