Sutures enriched with adipose-derived stem cells decrease the local acute inflammation after tracheal anastomosis in a murine model.
OBJECTIVE
Local inflammatory reaction and tension are the main causes of postoperative complications after tracheal surgery. Adipose-derived stem cells (ASCs) are known to have immunomodulatory activity. The exact mechanism of this activity is not known, although it is possible that they modulate the function of different cells involved in the immune response. Little is known of their impact on acute inflammation, especially in the problematic tracheal area. We aimed to study the effect of ASCs applied locally in an animal model of tracheal resection and anastomosis.


METHODS
ASCs from the subcutaneous fat of BDIX rats were infected for expression of the enhanced green fluorescent protein (eGFP) and were cultured with Polyglactin 910 sutures to obtain biosutures (ASC-coated sutures). After tracheal resection, 90 BDIX rats (syngeneic, autologous model) underwent anastomosis with biosutures (1.5 10(6) cells/biosuture [Group 1] or 0.5 10(6) cells/biosuture [Group 2]) or conventional sutures (Group 3). The animals were killed after 1, 4, 10, 30 or 60 days and histological and immunofluorescence studies were performed on the anastomotic areas. Inflammatory cell densities were graded semiquantitatively by the pathologist in a blinded fashion.


RESULTS
In the early period (1 and 4 days), the biosuture groups presented an atypical pattern of acute inflammation, characterized by the almost complete absence of neutrophils, and the presence of abundant lymphocytes and plasma cells, compared with the control group (P < 0.05). Moreover, abundant macrophages/monocytes were immunolocated around blood vessels near the biosutures and between biosuture threads 1 day after anastomosis, whereas the presence of macrophages/monocytes in animals treated with conventional sutures was discrete (P < 0.05). No differences were observed in the later period. No side effects in the biosuture groups were found.


CONCLUSIONS
Biosutures are a comfortable way of stem cell delivery to the surgical field without modification of the operative protocol. ASCs suppress the local acute inflammatory reaction (increased macrophage migration and decreased neutrophil infiltration) in the tracheal anastomosis and cause an early switch from acute to chronic inflammation.
Servicio de Cirugía General y del Aparato Digestivo, Hospital Universitario La Paz, Madrid, Spain. tihomir.hristov@gmail.com
Tihomir
T
Georgiev-Hristov
Mariano
M
García-Arranz
Ignacio
I
García-Gómez
Miguel Angel
MA
García-Cabezas
Jacobo
J
Trébol
Luz
L
Vega-Clemente
Prudencio
P
Díaz-Agero
Damián
D
García-Olmo
D000273:Adipose Tissue; D000714:Anastomosis, Surgical / Q000379:methods; D000818:Animals; D001705:Bioprosthesis; D004195:Disease Models, Animal; D005434:Flow Cytometry; D007150:Immunohistochemistry; D007249:Inflammation / Q000517:prevention & control*; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D011183:Postoperative Complications / Q000517:prevention & control; D011897:Random Allocation; D051381:Rats; D011919:Rats, Inbred Strains; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D013536:Suture Techniques; D013537:Sutures; D014132:Trachea / Q000473:pathology / Q000601:surgery*; D014140:Tracheotomy / Q000379:methods; D016896:Treatment Outcome