INTRAVENOUS INFUSION OF MESENCHYMAL STEM CELLS IS ASSOCIATED WITH IMPROVED MYOCARDIAL FUNCTION DURING ENDOTOXEMIA

Mesenchymal stem cells (MSCs) possess immunomodulatory properties and may curtail the inflammatory response that characterizes sepsis and other systemic inflammatory states. We aimed to determine whether intravenous infusion of MSCs is associated with reduced inflammation and improved myocardial function in a rat model of endotoxemia. Adult Sprague-Dawley rats were administered saline (vehicle) or LPS (5 mg/kg) via tail vein injection. Treatments, either vehicle or 2 x 10(6) MSCs, were infused 1 h later via tail vein. Animals were randomly assigned to the following groups: (a) vehicle + vehicle (control; n = 6), (b) LPS + vehicle (n = 6), or (c) LPS + MSCs (n = 6). Six hours after induction of endotoxemia, left ventricular ejection fraction (EF) and fractional shortening (FS) was assessed via parasternal short-axis M-mode echocardiography. Hearts and serum were collected for determination of cytokine levels via enzyme-linked immunosorbent assay. Animals injected with LPS + vehicle exhibited depressed cardiac function as indicated by a 26% and 37% reduction in EF and FS from baseline, respectively. Treatment with MSCs was associated with improved cardiac function compared with vehicle treatment as indicated by a reduction in EF and FS of only 10% and 17%, respectively (P < 0.05). Myocardial levels of TNF-alpha, IL-1 beta, and IL-6 were elevated in LPS-treated animals versus control. Similarly, serum levels of IL-1 beta, IL-6, and IL-10 were increased in LPS-treated animals. Treatment with MSCs, however, was associated with significant reductions in serum levels of IL-1 beta and IL-6 and in myocardial levels of TNF-alpha, IL-1 beta, and IL-6. In addition, treatment with MSCs was associated with a further increase in serum IL-10. Infusion of MSCs modulates the systemic inflammatory response and is associated with improved cardiac function during endotoxemia.