Biological pacemakers produced from human fat cells.
It is known that more than one million artificial pacemakers are implanted in patients across the globe annually due to abnormal heart rhythms. The devices are placed in the chest or abdomen, using electrical pulses to prompt the heart to beat normally. However, the devices need to be periodically examined by a physician, with many other failure risks to take into account. Therefore, a biologic pacemaker is more desirable as it is not a foreign object so better able to adapt to the body and would not have to be maintained by a physician, growing with the body. Now, a study from researchers at the University of Houston develops a biological pacemaker using stem cells found in fat, converting them to heart cells. The team states their ‘pacemaker-like’ cells function like the heart’s natural pacemaker cells. The opensource study is published in the Journal of Molecular and Cellular Cardiology.
Previous studies show the heart’s pacemaker cells are responsible for generating electrical impulses that set the normal rhythm and pace for blood to pump. When these cells go awry electronic pacemakers are routinely used, however, these pacemakers carry certain risks, typically only lasting five to 15 years. Biological pacemakers, conversely, wouldn’t need to be replaced, could adapt to the body and grow with the patient, and become fully integrated with the heart once implanted. The current study differentiates stem cells residing in the human body’s fat cells into cardiac progenitor cells, which in turn are programmed to conduct current and keep hearts beating.
The current study utilizes stem cells found in fat to produce cardiac progenitor cells that are then programmed into pacemaker-like cells using a cocktail of SHOX2, HCN2, and TBX5 (SHT5) transcription factors, and channel proteins. To determine the functional efficiency of the reprogrammed cells using the SHT5 combination of transcription factors, the hyperpolarized-activated or HCN current was measured using patch-clamp recordings. Data findings show the pacemaker-like cells exhibit the HCN current characteristic of natural pacemaker cells.
Results show the pacemaker-like cells share similar gene expression profiles with natural cardiac pacemaker cells, meaning they could be programmed to become more like an actual pacemaker cell. The group states they also supplied their pacemaker-like cells with plasma membrane channel proteins, which are gates opening up in cells to allow outside chemicals, that could be used to reprogram the heart cells in vitro. They go on to add their reprogrammed pacemaker-like cells may lead to new therapies for cardiac failure.
The team surmises they have used fat stem cells to develop a biological pacemaker for the heart, pacemaker-like cells. For the future, the researchers state their pacemaker-like cells may become an alternative treatment for heart disorders without the limitations of artificial electronic pacemaker implants.
Source: Texas Medical Center