Ischemic Preconditioning and Tacrolimus Pretreatment as Strategies to Attenuate Intestinal Ischemia-Reperfusion Injury in Mice

STRINGA, P; ROMANIN, D; LAUSADA, N; MACHUCA, M; RAIMONDI, J; CABBANE, A; RUMBO, M; GONDOLESI, G

TRANSPLANTATION PROCEEDINGS

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 2013 vol. 45 p. 2480 - 2485

0041-1345

The intestine is highly sensitive to ischemia-reperfusion injury (IRI), a phenomenon occurring in different intestinal diseases. Several strategies to mitigate IRI are in experimental stages; unfortunately, no consensus has been reached about the most appropriate one. We report a protocol to study ischemic preconditioning (IPC) evaluation in mice and to combine IPC and tacrolimus (TAC) pretreatment in a warm ischemia model. Mice were divided into treated (IPC, TAC, and IPC + TAC) and untreated groups before intestinal ischemia. IPC, TAC, and IPC + TAC groups were able to decrease postreperfusion nitrites levels (P < .05). IPC-containing groups had a major beneficial effect by preserving the integrity of the intestinal histology (P < .05) and improving animal survival (P < .002) compared with TAC alone or the untreated group. The IPC + TAC group was the only one that showed significant improvement in lung histological analysis (P < .05). The TAC and IPC + TAC groups down-regulated intestinal expression of interleukin (II)-6 and IL1b more than 10-fold compared with the control group. Although IPC and TAC alone reduced intestinal IRI, the used of a combined therapy produced the most significant results in all the local and distant evaluated parameters. Ischemia-reperfusion injury (IRI) of the intestine is part of the pathophysiology of many intestinal disorders, such as strangulated hernia, volvulus, necrotizing enterocolitis, mesenteric embolic event, procoagulant disorders, and intestinal transplantation. It is an important factor associated with morbidity and mortality in both surgical and trauma patients.1 IRI is a dynamic process involving two distinctive yet interrelated phases of ischemic organ damage and inflammation-mediated reperfusion injury. Multiple cellular and molecular pathways contribute and regulate tissue/organ damage, eg, the exposure of vascular neoantigens interacting with complement-activating natural antibodies, and the uncontrolled generation of reactive oxygen species and proinflammatory mediators.1, 2 and 3 A hallmark of intestinal IRI is epithelial cell damage, accompanied by loss of brush border enzymes and absorptive function. In the case of the intestine, IRI may alter the integrity of the mucosal enteric barrier, promoting bacterial translocation and sepsis. Pro-inflammatory factors, such interleukin-1 beta (IL-1b), interleukin-18 (IL-18), and other cytokines, are produced in the intestine during IRI, contributing to a local and systemic inflammatory response leading to damage in remote organs, such as the liver and lungs, causing multiorgan failure and death.4 Strategies to mitigate IRI must be designed for basic and translational research in the intestinal surgical field including transplantation. Several strategies have been proposed to protect tissues from IRI, such as antioxidant administration, hypothermia, inflammatory mediator or adhesion molecule modulation, ischemic preconditioning (IPC), or different drug therapies.5 In 1986, Murry et al6 introduced the IPC concept as a way to reduce myocardial IRI. They described the beneficial effect of short periods of coronary occlusion followed by short periods of reperfusion, before a prolonged ischemic phase, and found a reduction of ischemic myocardial injury in dogs. IPC has been studied in different tissues and organs, including the intestine, since it was first described.7 Tacrolimus (TAC) is a macrolide antibiotic compound, a metabolite of the fungus Streptomyces tsukubaensis, discovered in 1984. Potential applications of this drug are still under investigation. Favorable results have been obtained with the use of TAC in various immune-mediated phenomena, including inflammatory bowel disease and solid organ rejection prevention and treatment.8 Several studies have shown that TAC can ameliorate IRI by slowing adenosine triphosphate (ATP) depletion, reducing free radical formation, inhibiting calcium-dependent pathways in the early phase of IRI, and interfering in several intracellular signaling pathways, including NFkB.9 We recently optimized a mice intestinal IRI model and established a maximum tolerable warm ischemia time beyond which the systemic impact would lead to death.10 This model provides an alternative, which is to develop strategies aiming to ameliorate the IRI and secondary damage, resulting in survival. In the present study we used this model to evaluate the effect of IPC and TAC pretreatment as strategies to diminish intestinal IRI in mice. Although several studies were conducted to analyze the effect of both strategies as therapeutic options to attenuate IRI, no study combined TAC and IPC to prove any interactive effect between these two treatments. Therefore, the present study was designed to better understand the pathophysiology of IRI and to establish strategies to mitigate it.