Jimmy Ruffin once asked, “What becomes of the broken hearted?” and the answer is normally found on a barstool or at the bottom of an ice cream tub. But for those suffering from the much more visceral consequences of a heart attack, the therapeutic avenues down which they can travel are more limited and less effective. Additionally, the adult heart itself has a limited regenerative capacity, and so many researchers have focused on ways to boost heart muscle cell proliferation to combat the loss of function following heart attacks.
One of these researchers is Pilar Ruiz-Lozano, and in her new study, she hoped to discover if factors expressed in certain areas of the heart to promote heart muscle formation during development could enhance heart regeneration in adults. Any interesting factors could then be loaded onto a three-dimensional collagen patch and used to promote heart regeneration.
Her study, published in Nature, found that:
- Cells of the epicardium, the membrane covering the muscular wall of the heart, promoted muscle cell division in co-culture experiments.
- Factors secreted by the epicardial cells improved heart function following injury.
- However, following heart attack, epicardial cells lose Fstl1 expression, whereas heart muscle gains Fstl1 expression, and this inhibits heart regeneration.
- To counter this, the researchers placed an hFSTL1-loaded collagen patch on mouse and pig hearts (small and large animal models) following induced heart attacks.
- Excitingly, the patch enhanced the heart’s regenerative capacity and improved heart function.
While this Fstl1-laden patch seems like an effective cell-free therapy to regenerate the heart, some questions still remain. Why and how does the expression of Fstl1 switch between tissues, and why does muscle-based expression of Fstl1 not have any great effect? The authors suggest that this may be due to differential post-translational modification and hope that further studies will show how we can take advantage of the pro-regenerative capacity of FSTL1.
So take heart, an effective means to boost heart regeneration may be just around the corner, read all about it in Nature, Sept 2015.