“Second-generation” stem cells for cardiac repair

Abstract

Over the last years, stem cell therapy has emerged as an inspiring alternative to restore cardiac function after myocardial infarction. A large body of evidence has been obtained in this field but there is no conclusive data on the efficacy of these treatments. Preclinical studies and early reports in humans have been encouraging and have fostered a rapid clinical translation, but positive results have not been uniformly observed and when present, they have been modest. Several types of stem cells, manufacturing methods and delivery routes have been tested in different clinical settings but direct comparison between them is challenging and hinders further research. Despite enormous achievements, major barriers have been found and many fundamental issues remain to be resolved. A better knowledge of the molecular mechanisms implicated in cardiac development and myocardial regeneration is critically needed to overcome some of these hurdles. Genetic and pharmacological priming together with the discovery of new sources of cells have led to a “second generation” of cell products that holds an encouraging promise in cardiovascular regenerative medicine. In this report, we review recent advances in this field focusing on the new types of stem cells that are currently being tested in human beings and on the novel strategies employed to boost cell performance in order to improve cardiac function and outcomes after myocardial infarction.

Keywords: Stem cells; Cardiac repair; Myocardial infarction; Heart failure; Second generation

Core tip: Myocardial infarction and heart failure represent two of the most prevalent and fatal diseases. Stem cell therapies represent a novel approach capable of restoring the cellular loss observed in these conditions. Data from initial human studies have been encouraging but inconclusive. However, refinements in cell populations as well as new stem cell sources are currently being tested in large phase III clinical trials after showing positive results in preclinical models and early clinical reports, thus holding a promise for the achievement of a true myocardial regeneration after myocardial infarction. We review here recent developments in this field.