A team of researchers at the University of Houston have created functional pacemaker-like heart cells from fat-derived stem cells, which could be used as biological pacemakers. The pacemaker-like cells could be used as an alternative treatment method for conduction system disorders and repair of the heart following a heart attack, eliminating the need for electronic pacemakers.
The process involves harvesting adipogenic mesenchymal stem cells from fat, converting the stem cells into cardiac progenitor cells, and then reprogramming them into the conducting cells of the heart to create next-generation biologic pacemakers.
These cell types are present in the sinoatrial node (SAN), the main pacemaker of the heart responsible for generating electric current and the heartbeat, which is an essential part of the electrical cardiac conduction system (CCS). If the SAN fails, or there is any fault in the CCS that blocks the electrical current, it results in arrhythmias.
Electronic pacemakers are used to correct arrhythmias, but they have their limitations. The devices must be implanted, and while this is a safe procedure, any surgery carries a risk. The devices also need to be regularly inspected by physicians and the devices only have a limited lifespan as the batteries powering them will eventually die. Before that happens, the pacemakers need to be replaced. Pacemakers can also suddenly stop working. Each year, around 600,000 electronic pacemakers are implanted into patients.
Bradley McConnell, University of Houston associate professor of pharmacology, and his team successfully converted cardiac progenitor cells that had been created from fat cells into pacemaker-like cells in vitro using a combination of three transcription factors – SHOX2, HCN2, and TBX5 (SHT5) – and a plasma membrane channel protein. These cells would form the basis of a biological pacemaker when introduced into patients, eliminating the need for an electronic pacemaker device.
A biological pacemaker would not need to be maintained by a physician, as that would be taken care of by the body of the patient. Biological pacemakers would not need to be replaced or checked as they would adapt to what is happening in the body and would not wear out over time. Treatment would be a one-off procedure.
You can read more about the study in the paper – Transcription factors ETS2 and MESP1 transdifferentiate human dermal fibroblasts into cardiac progenitors – was recently published in the Journal of Molecular and Cellular Cardiology.