Extracellular matrix components of adipose derived stromal cells promote alignment, organization, and maturation of cardiomyocytes in vitro.

Adipose derived stromal cells (ADSC) are relevant therapeutic agents to treat myocardial infarction (MI) in clinical trials. Soluble factors secreted by ADSC, such as growth factors and cytokines, suppress inflammation and apoptosis while promoting angiogenesis and the proliferation of cardiomyocytes (CM). Moreover, ADSC synthesize extracellular matrix (ECM) components into the intercellular space which might contribute to their therapeutic capacity. Thus, ADSC might directly modulate the post-MI microenvironment through a combination of paracrine and juxtacrine signaling. In this study, the juxtacrine role of ADSC and ADSC-derived ECM on the organization and maturation of CM was investiagated. Human ADSC synthesized and deposited a heterogenous and complex mixture of ECM components such as collagen I, III, IV, fibronectin, elastin as well as the matricellular protein periostin. Cocultures of rodent CM with human ADSC or with human ADSC-derived ECM components enhanced the cardiomyocyte alignment, their intercellular connections and the maturation of their sarcomeres, while the proliferation rate of the CM was increased and their level of hypertrophy reduced. The use of human ADSC-derived ECM could serve both to augment in vitro tissue-engineered myocardial constructs and to improve myocardial remodeling after infarction.