Each year, an estimated 785,000 people in the United States will have a new coronary attack and 470,000 will have a recurrent attack, according to the National Heart, Lung and Blood Institute. In addition, an estimated 195,000 silent myocardial infarctions (MIs) occur each year. Estimated annual incidence of MI is 610,000 new attacks and 325,000 recurrent attacks.
In spite of the last several years of optimism and great interest in cell or tissue regeneration in the postinfarction myocardium, progress has been slow. According to an article in the European Journal of Cardiovascular Prevention & Rehabilitation (28; 127–138, February 2010), post-MI patients have shown hints of potential benefit, but not like expected. The challenge to repair damaged myocardium has presented more complex hurdles than anticipated. The researchers concluded that while the promise for cell therapy continues to be significant in myocardial regeneration, so are the challenges.
However, new discoveries are being made every day. Scientists at Weill Cornell Medical College have developed a new way to generate functional blood vessel cells from human stem cells. They created a method for turning human embryonic and pluripotent stem cells into plentiful, functional endothelial cells critical to the formation of blood vessels. It is now feasible that these cells might be able to be injected into humans in the near future, enabling healing of damaged organs and tissues. It is discoveries like these that will drive innovative products for MI and CHD closer to commercialization.
Researchers using human umbilical cord blood cells have been studying their use in treating myocardial infarction. The researchers, from Pontificia Universidade Catolica do Parana and Instituto Carlos Chagas have evaluated the therapeutic potential of purified and expanded CD133+ cells derived from human umbilical cord blood to treat myocardial infarction by injecting them intramyocardially into rats. The theory is that human umbilical cord blood cell–derived endothelial progenitor cells (EPCs) could be an alternative to rescue impaired stem cell function in the sick and elderly because patients at high cardiovascular risk have fewer EPCs and their EPCs exhibit greater in vitro senescence. The recently published results (Experimental Biology and Medicine, January 2010) show that expanded cells ex vivo exhibited increased expression of mature endothelial cells markers and formed tubule-like structures in vitro. Only the expanded cells expressed VAGF mRNA. Both the purified and expanded cells showed promising results for use in cellular cardiomyoplasty.
The incidence of myocardial infarction by age and sex is shown in the exhibit below.
Incidence of Myocardial Infarction by Age and Sex, 1987–2004
Source: National Heart Lung and Blood Institute, 2010, and MedMarket Diligence Report #S520.
Companies focused on cell and tissue regeneration in treatment of myocardial infarction or ischemia include Baxter International, Capricor, Capstone Therapeutics, Cytori Therapeutics, Garnet BioTherapeutics, Miltenyi Biotec and others.