Hepatocyte Growth Factor Helps After Heart Attack

Los Angeles, CA -

It is known that mesenchymal stem cells are useful for treating patients after a heart attack. What is however unknown is exactly how these cells mediate their effects. On the one hand mesenchymal stem cells are known to inhibit various inflammatory reactions by modulating the immune system. Therefore by suppressing inflammation administration of mesenchymal stem cells may be useful for the post heart attack period in order to suppress the cascade of ongoing tissue damage.

Recently, a publication came out (Anderson et al. The Role of Cytoprotective Cytokines in Cardiac Ischemia/Reperfusion Injury. J Surg Res. 2007 Aug 31) describing another mechanisms by which mesenchymal stem cells may be useful in the post-infarct period. The authors speculated that not the mesenchymal stem cells themselves, but different growth factors generated by the cells may contribute to repair of the injured myocardium after the heart attack. Specifically, two growth factors were assessed: hepatocyte growth factor (HGF) and stromal derived growth factor-1 (SDF-1), otherwise known as the CXCL12.

HGF is known to have various regenerative properties. For example, it is known that HGF stimulates production of new blood vessels which is a process that is important in healing the myocardium after injury. Additionally, CXCL12 is one of the "danger signals" that injured heart tissue makes after a heart attack in order to mobilize stem cells to the infarct area.

What the investigators of the current study did is they induced myocardial infarcts in rats and subsequently applied polymers that were soaked with either CXCL-12 or HGF to the injured myocardium.

Four weeks after the injury the left ventricular ejection fraction was increased in the mice that recieved HGF and the volume of the left ventricle was decreased. Twelve weeks after, contractility was increased in the mice that recieved the HGF. Additionally, HGF decreased the infarct size by 4 fold as compared to control.

No improvement was seen in the mice that recieved CXCL12.

These data suggest that in addition to beneficial effects in limb ischemia, HGF is useful for cardioprotection. It would have been nice however if the researchers included a group of rats recieving mesenchymal stem cells as a control. Even better if mesenchymal stem cells and HGF were administered together. No doubt that future experiments will do this, and we will discuss them here on StemCellPatents.com.