The effect of degradable polymer surfaces on co-cultures of monocytes and smooth muscle cells.

Strategies to optimize biomaterial chemistry for applications in vascular tissue engineering attempt to promote endothelial and smooth muscle cell recruitment into porous material constructs. The primary objective is to facilitate relevant tissue formation in a wound healing versus pro-inflammatory manner. The present work investigated the interactive co-cellular response of human monocytes and human vascular smooth muscle cells (VSMCs) with a novel degradable, polar/hydrophobic/ionic (D-PHI) polyurethane and compared it to a commercially available biomaterial, poly-lactic-glycolic acid (PLGA) as well as tissue culture polystyrene (TCPS). D-PHI triggered a smaller pro-inflammatory response (acid phosphatase, esterase, tumor necrosis factor-α) at later time points (>14 d) than PLGA suggesting that monocytes may be transitioning to a more wound-healing phenotype on the D-PHI surface. When D-PHI was coated with collagen, monocyte cell attachment did not differ with the native D-PHI; however, PLGA showed significant differences between collagen coated versus uncoated surfaces. There were more VSMCs and monocytes attached in co-culture to D-PHI when compared to PLGA. Co-cultures on D-PHI released more IL-10 (anti-inflammatory) than monocytes cultured alone, while the VSMCs retained the expression of its marker protein calponin. Together the above data suggest that co-culturing monocytes with VSMCs may aid in stimulating the attachment of VSMCs to D-PHI while eliciting the desired functional phenotypes for both monocytes (i.e. low inflammation based on IL-10 values) and VSMCs (expressing calponin, a marker of contractility). Moreover, the results of this study demonstrated that D-PHI performed equally or better to PLGA in terms of the assayed biological parameters.