Gut Permeability and Glucose Absorption Are Affected at Early Stages of Graft Rejection in a Small Bowel Transplant Rat Model

Abstract

Background. Intestinal transplantation (ITx) faces many challenges due to the complexity of surgery and to the multiple immunological reactions that lead to the necessity of rigorous follow-up for early detection of acute cellular rejection (ACR). Our aim was to determine the kinetics of ACR using an experimental ITx model, with emphasis in the characterization of the process using different approaches, including the use of functional assays of absorptive and barrier function. Methods. ITx in rats conducting serial sampling was performed. Clinical monitoring, graft histology, proinflammatory gene expression, and nitrosative stress determination were performed. Also, glucose absorption, barrier function using ovalbumin translocation, and contractile function were analyzed. Results. The model used reproduced the different stages of ACR. Allogeneic ITx recipients showed signs of rejection from postoperative day (POD) 5, with increasing severity until 12 POD. Histological evaluation showed mild rejection in early sampling and severe rejection at late stages, with alterations in all graft layers. IL-6, CXCL 10, IFNg, and nitrite plasmas levels showed behavior coincident with histopathology. Remarkably, allogeneic grafts showed a marked alteration of glucose absorptive capacity from POD 5 that was sustained until endpoint. Coincidently, barrier function alteration was evidenced by luminal ovalbumin translocation to serum. Contractile function was progressively impaired along ACR. Conclusions. Glucose absorption and barrier function are altered at early stages of ACR when histological alterations or gene expression changes were much subtle. This observation may provide simple evaluation tools that could be eventually translated to the clinics to contribute to early ACR diagnosis.

Modified Multivisceral Transplantation with Native Spleen Removal in Rats

“…Due to the limited evidence in experimental models of MMVTx in rats, 7 we have used our previous experience in rodents experimental surgery and the extensive literature published in isolated small bowel and multivisceral transplantation to transfer to our heterotopic MMVTx model as well as pre-and post-surgical animal handling, anesthetics, analgesics, and antibiotics, with a very good effectiveness. 8,9,[15][16][17][18][19][20] Focusing on vascular anastomosis, we performed an end-to-side arterial anastomosis between the donor and recipient aorta following the technique reported by Galvao et al In contrast, due to the heterotopic graft position, we performed a hand-to-sewn venous anastomosis between donor PV and recipient cava vein instead of the described cuff technique. 7 In agreement with the multicenter work published by our surgeons group in isolated intestinal transplantation in rats, 8 main complications observed during recipient MMVTx surgery were related to the arterial and venous anastomosis confection.…”

“…In the same way, terminal ileostomy was performed following reported techniques. 9,18,19 Other important contribution in the MMVTx model is the inclusion of the spleen in the graft and the native spleen removal. In the clinic, the spleen is no longer included in the graft because the risk of GVHD is increased.…”

“…As we previously reported, a standardized quantitative score for clinical monitoring of recipient was used. 9 Briefly, animal weight, ocular secretion, hair appearance, and posture, among others parameters, were considered. Each recipient received a general score resulting from adding each evaluated parameter.…”

The Novel N,N‐bis‐2‐Hydroxyethyl‐2‐Aminoethanesulfonic Acid–Gluconate–Polyethylene Glycol–Hypothermic Machine Perfusion Solution Improves Static Cold Storage and Reduces Ischemia/Reperfusion Injury in Rat Liver Transplant

“…An immunohistochemical study to evaluate apoptosis was performed in each group by the terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick‐end labeling (TUNEL) technique using the In‐Situ Cell Death TMR (Roche, Basel, Switzerland) following the manufacturer's instructions. Counting of apoptotic cells was performed considering the number of apoptotic cells in 10 fields per sample (including 5 photographs per sample) using a FV1000 confocal microscope (Olympus, Tokyo, Japan) …”

Comparison in outcome with tailored antibiotic prophylaxis postoperatively in pediatric intestinal transplant population

“…The majority of patients receiving intestinal transplants have a decrease in the blood‐gut barrier. Their leaky bowel permits recurrent bloodstream infections . With each course of antibiotics to address each bloodstream infection, these patients take steps to development of more and more resistant organisms .…”