Conditioned medium from human amniotic mesenchymal stromal cells limits infarct size and enhances angiogenesis

The paracrine properties of human amniotic membrane-derived mesenchymal stromal cells (hAMCs) have not been fully elucidated. The goal of the present study was to elucidate whether hAMCs can exert beneficial paracrine effects on infarcted rat hearts, in particular through cardio-protection and angiogenesis. Moreover, we aimed to identify the putative active paracrine medi-ators.hAMCswereisolated,expanded,andcharacterized.Invitro,conditionedmediumfromhAMC (hAMC-CM) exhibited cytoprotective and proangiogenic properties. In vivo, injection of hAMC-CM into infarcted rat hearts limited the infarct size, reduced cardiomyocyte apoptosis and ventricular remodeling, andstrongly promoted capillary formation at theinfarct border zone. Genearray analysis led to the identification of 32 genes encoding for the secreted factors overexpressed by hAMCs. Among these, midkine and secreted protein acidic and rich in cysteine were also upregulated at the protein level. Furthermore, high amounts of several proangiogenic factorswere detected in hAMC-CMbycytokine array.Ourresultsstronglysupport theconcept thattheadministrationof hAMC-CM favors the repair process after acute myocardial infarction.