Back to 2014 Annual Meeting Abstracts

BACKGROUND
While surgical sutures are medical devices used to maintain wound edges in proper apposition until wound healing is sufficiently established, they are foreign bodies, and as such, are capable of provoking a local, foreign body-associated immune response. This may result in the counterproductive potentiation of the inflammatory phase of wound healing, leading to wound breakdown, suture spitting or the formation of granulomas, hypertrophic scars or keloids. In an effort to reduce these suboptimal outcomes associated with an exaggerated inflammatory response, we coated inflammatory inducing plain gut and silk sutures with a novel family of synthetic, biodegradable amino acid based poly(ester amide) (AA-PEA) polymers that has demonstrated attenuation of the inflammatory response in vitro.
METHODS
Following the synthesis of 6 different AA-PEA polymers, 3-0 plain gut and 3-0 silk sutures were completely coated with a single type of AA-PEA polymer via a submersion technique. Subsequently, an uncoated, control suture was implanted through the long axis of the left gluteus muscle of 8-week old C57BL/6 male mice and similarly, an AA-PEA coated suture was implanted through the right gluteus muscle. An additional control and AA-PEA coated suture was subcutaneously implanted in the dorsa of each animal. Following 28 days of implantation, animals were euthanized and bilateral gluteal muscles and subcutaneous suture implants were harvested.
Histological sections were obtained through the axis perpendicular to the suture track within the gluteus muscle and subsequently, stained with hematoxylin and eosin (H&E). Light photomicrographs of 3 representative images for each AA-PEA-coated suture were obtained and thereafter, digital image processing software (Image J) was used to quantify the mean area of inflammation surrounding each suture. Subcutaneously implanted sutures were tested for tensile strength using an Instron Testing System 5566.
RESULTS
Mean areas of surrounding inflammation were reduced for all AA-PEA coated sutures when compared to non-coated controls after 28 days of suture implantation. Furthermore, after 28 days of suture implantation, 3-0 silk sutures coated with AA-PEA polymers showed an increase in breaking stress. However, 3-0 plain gut sutures coated with AA-PEA polymers showed a reduction in breaking stress after 28 days of suture implantation.
CONCLUSIONS
By coating inflammation-provoking silk sutures with our biocompatible, biodegradable AA-PEA polymers, we have successfully designed an effective method for reducing the suture-mediated inflammatory response while simultaneously increasing the tensile strength of 3-0 silk sutures. This may potentially translate into decreased functional and cosmetic morbidities associated with an extended inflammatory phase of wound healing, decreasing wound breakdown and increasing the development of an optimal aesthetic scar. Thus, we believe our AA-PEA coated sutures hold promise in the development of the next generation of sutures.