US funding for research into cardiac regeneration using stem cells is coming to an end after a five-year investigation revealed over 30 studies in this field must be retracted.
In October 2018, The New York Times reported that Harvard and Bringham and Women’s Hospital’s ongoing investigation into Dr Piero Anversa, a prominent researcher, showed he had ‘fabricated’ and ‘falsified’ data in 31 studies.  More recently, Circulation and Circulation Research journals redacted a further 13 articles from Dr Anversa’s laboratory due to ‘issues with the data’. 
The original research apparently showed that stem cells from bone marrow could be injected into the heart, stimulating cardiac regeneration. However, subsequent studies failed to replicate the results, and papers in journals such as Nature demonstrated that bone marrow does not lead to the formulation of myocytes. Despite this, US funding for research into this area continued.
An editorial published in JAMA Cardiology details the events that lead to the recent decision by Harvard and Bringham and Women’s Hospital, and postulated some reasons behind the continuing research in this area. The authors write: “Unchecked optimism by many in the cardiology community led to rapidly initiated clinical trials despite the controversy, and over the next decade, thousands of patients received cardiac infusions of putative stem cells both within and outside of clinical trials sponsored by the National Institutes of Health (NIH), costing taxpayers additional millions of dollars.” 
This editorial comes shortly after research from the Hubrecht Institute, Uchtrect University, The Netherlands, which confirms that adult hearts do not contain stem cells.  Using mice hearts, researchers created a ‘cell-by’cell’ map of the heart where they were able to look at all dividing heart cells before and after a myocardial infarction. Here, they observed that cardiac cells are not capable of generating new heart muscle. However, they also noted now connective tissue responded to MI by producing scar tissue which is important for ‘maintaining the integrity of the heart’. 
This research effectively draws a line under the notion that cardiac cells are capable of regeneration. Research must now focus on alternative potential mechanisms and signalling pathways, and how they can impact the heart’s healing process.
- Profiling proliferative cells and their progeny in damaged murine hearts. Kretzschmar K, Post Y, Bannier-Hélaouët M, et al., Proceedings of the National Academy of Sciences (PNAS) 2018. https://www.pnas.org/content/early/2018/12/06/1805829115