Effect of bacterial exposure on acellular human dermis in a rat ventral hernia model.
BACKGROUND
Effectiveness of acellular human dermis (AHD) as an alternative to synthetic mesh in contaminated fields has been described. Cellular migration after implantation and corresponding strength of attachment is not well documented. Our aim is to correlate AHD vascularization, fibroblast migration, and strength of attachment with presence of inflammatory cells in clean and contaminated fields.


METHODS
Lewis rats were randomized to a control and three experimental groups. AHD was placed as an onlay over the intact abdominal wall. Experimental groups (n=72) were exposed to Staphylococcus aureus at 1 x 10(4), 1 x 10(5), or 1 x 10(6) by direct application; controls (n=12) were not exposed. At 5 and 28 d, abdominal walls were explanted and tissue ingrowth assessed via tensiometry measuring energy (E) and max stress (MS) at the AHD-tissue interface. Vascularity, fibroblast migration, and inflammatory cell migration were compared using light microscopy.


RESULTS
Shear strength reported as energy and max stress were significantly greater at 28 versus 5 d in all experimental groups, remaining unchanged in controls. Plasma cells and histiocytes significantly increased in all groups; macrophages increased in experimental groups only. Vascular ingrowth increased significantly in all groups; fibroblast migration was greater in controls and 1 x 10(6) exposed group only.


CONCLUSIONS
Contamination of AHD results in inflammatory cell influx and a surprising increase in shear strength. Interestingly, shear strength does not increase without contamination. Inflammation stimulates vascular ingrowth, but not equally significant fibroblast migration. Longer survivals are required to determine if energy and max stress of controls increase, and fibroblast migration follows vascular ingrowth.
Division of GI and Minimally Invasive Surgery, Department of General Surgery, Carolinas Medical Center, Charlotte, North Carolina 28203, USA.
Jennifer E
JE
Keller
Charles J
CJ
Dolce
K Christian
KC
Walters
Jessica J
JJ
Heath
Richard D
RD
Peindl
Kent W
KW
Kercher
Amy E
AE
Lincourt
B Todd
BT
Heniford
David A
DA
Iannitti
D000818:Animals; D001705:Bioprosthesis / Q000382:microbiology*; D002465:Cell Movement; D003094:Collagen; D005347:Fibroblasts / Q000502:physiology; D059685:Herniorrhaphy; D006801:Humans; D008297:Male; D018919:Neovascularization, Physiologic; D011897:Random Allocation; D051381:Rats; D011917:Rats, Inbred Lew
D003094:Collagen