Prevention of incisional hernia after kidney transplantation: study protocol for a randomized controlled trial.

BACKGROUND: Incisional hernia is a common complication after kidney transplantation with an incidence of 1.6-18%. Concerning non-transplant patients, a recently published meta-analysis describes a reduction of the incidence of incisional hernia of up to 85% due to prophylactic mesh replacement in elective, midline laparotomy. The aim of our study is to show a reduction of the incidence of incisional hernia after kidney transplantation with minimal risk for complication. METHODS/DESIGN: This is a blinded, randomized controlled trial comparing time to incisional hernia over a period of 24 months between patients undergoing kidney transplantation and standardized abdominal closure with or without prophylactic placement of ProGrip™ (Medtronic, Fridley, MN, USA) mesh in an onlay position. As we believe that the mesh intervention is superior to the standard procedure in reducing the incidence of hernia, this is a superiority trial. DISCUSSION: The high risk for developing incisional hernia following kidney transplantation might be reduced by prophylactic mesh placement. ProGrip™ mesh features polylactic acid (PLA) microgrips that provide immediate, strong and uniform fixation. The use of this mesh combines the effectiveness demonstrated by the macropore propylene meshes in the treatment of incisional hernias, a high simplicity of use provided by its capacity for self-fixation that does not increase significantly surgery time, and safety. TRIAL REGISTRATION: ClinicalTrials.gov NCT04794582. Registered on 08 March 2021. Protocol version 2.0. (02-18-2021).

A new aggressive xenograft model of human colon cancer using cancer-associated fibroblasts.

BACKGROUND: Colorectal cancer is the second leading cause of cancer death. Almost half of the patients present recurrence within 5 years after the treatment of the primary tumor, the majority, with metastasis. On the other hand, in the search for new animal models that simulate metastatic cancer, it has been suggested that fibroblasts immersed in the peritumoral stroma (cancer-associated fibroblasts (CAFs)), play a relevant role in the development of cancer. The objective of this study was to identify an adequate animal model to study metastatic colon cancer and the application of new treatments. METHODS: Human CAFs and normal fibroblasts (NF) for transplant and culture were obtained from surgical fresh samples of patients with adenocarcinoma of sigmoid colon. Stromal cell purity was evaluated by morphology and immunostaining with vimentin (VIM) as a fibroblast marker and anti-proColXIα1 as a specific human CAF marker. Phenotypic characterization of cultured stromal cells was performed by co-staining with mesenchymal and epithelial cell markers. For identification in mice, human CAFs were labeled with the PKH26 red fluorescence dye. Cell line HT-29 was used as tumor cells. Transplant in the head of the pancreas of 34 SCID mice was performed in four different groups, as follows: I. 150,000 CAFS (n = 12), IIa. 1.5 million HT29 cells (n = 7), IIb. 150,000 NF+1.5 million HT29 cells (n = 5), III. 150,000 CAFS+1.5 million HT29 cells (n = 10). After euthanasia performed one month later, histological analysis was made using hematoxylin-eosin and anti-proColXIα1. A histopathological score system based on three features (tumor volume, desmoplasia and number of metastasized organs) was established to compare the tumor severity. RESULTS: The CAFs and NF cultured were proColXIα1+/VIM+, proColXIα1/alphaSMA+ and proColXIα1+/CK19+ in different proportions without differences among them, but the CAFs growth curve was significantly larger than that of the NF (p < 0.05). No tumor developed in those animals that only received CAFs. When comparing group II (a + b) vs. group III, both groups showed 100% hepatic metastases. Median hepatic nodules, tumor burden, lung metastases and severity score were bigger in group III vs group II (a + b), although without being significant, except in the case of the median tumor volume, that was significantly higher in group III (154.8 (76.9-563.2) mm3) vs group II (46.7 (3.7-239.6) mm3), p = 0.04. A correlation was observed between the size of the tumor developed in the pancreas and the metastatic tumor burden in the liver and with the severity score. CONCLUSION: Our experiments demonstrate that cultured CAFs have a higher growth than NF and that when human CAFs are associated to human tumor cells, larger tumors with liver and lung metastases are generated than if only colon cancer cells with/without NF are transplanted. This emphasizes the importance of the tumor stroma, and especially the CAFs, in the development of cancer.