The Effects of Rapamycin on the Intestinal Graft in a Rat Model of Cold Ischemia Perfusion and Preservation.

Attenuating the rheological and structural consequences of intestinal ischemia-reperfusion-injury (IRI) is important in transplant proceedings. Preconditioning is an often-proposed remedy. This technique uses physical or pharmacological methods to manipulate key ischemia pathways, such as oxidation, inflammation, and autophagy, prior to ischemia. This study determined the time-dependent effects of Rapamycin preconditioning on small-bowel grafts undergoing cold ischemia perfusion and preservation. Our main parameters were mucosa and cell injury and autophagy. A total of 30 male Wistar rats were divided into 5 groups: sham, preservation-control, and 3 treated groups (Rapamycin administered either 0, 30, or 60 min prior to perfusion). After perfusion, the intestines were placed in chilled IGL-1 solution for 12 h. Thereafter, they were reperfused. Histology and bioanalysis (LDH and lactate) were used to ascertain intestinal injury while immunohistochemistry was used for measuring changes in autophagy markers (Beclin-1, LC3B, and p62 proteins). The results show no significant difference amongst the groups after vascular perfusion. However, intestinal injury findings and autophagy changes demonstrate that administering Rapamycin 30 min or 60 min prior was protective against adverse cold ischemia and reperfusion of the intestinal graft. These findings show that Rapamycin is protective against cold ischemia of the small intestine, especially when administered 30 min before the onset.

Subnormothermic isolated organ perfusion with Nicorandil increased cold ischemic tolerance of liver in experimental model.

BACKGROUND: The cold ischemia -reperfusion injury may lead to microcirculatory disturbances, hepatocellular swelling, inflammation, and organ dysfunction. Nicorandil is an anti-ischemic, ATP-sensitive potassium (KATP) channel opener drug and has proved its effectiveness against hepatic Ischemia/Reperfusion (I/R) injury. OBJECTIVE: This study aimed to investigate the effect of Nicorandil on mitochondrial apoptosis, oxidative stress, inflammation, histopathological changes, and cold ischemic tolerance of the liver in an ex vivo experimental isolated-organ-perfusion model. METHODS: We used an ex vivo isolated rat liver perfusion system for this study. The grafts were retrieved from male Wistar rats (n = 5 in each), preserved in cold storage (CS) for 2 or 4 hours (group 1, 2), or perfused for 2 or 4 hours (group 3, 4) immediately after removal with Krebs Henseleit Buffer (KHB) solution or Nicorandil containing KHB solution under subnormothermic (22-25°C) conditions (group 5, 6). After 15 minutes incubation at room temperature, the livers were reperfused with acellular, oxygenated solution under normothermic condition for 60 minutes. RESULTS: In the Nicorandil perfused groups, significantly decreased liver enzymes, GLDH, TNF-alpha, and IL-1ß were measured from the perfusate. Antioxidant enzymactivity was higher in the perfused groups. Histopathological examination showed ameliorated tissue deterioration, preserved parenchymal structure, decreased apoptosis, and increased Bcl-2 activity in the Nicorandil perfused groups. CONCLUSIONS: Perfusion with Nicorandil containing KHB solution may increase cold ischemic tolerance of the liver via mitochondrial protection which can be a potential therapeutic target to improve graft survival during transplantation.

Characterizing Autophagy in the Cold Ischemic Injury of Small Bowel Grafts: Evidence from Rat Jejunum.

Cold ischemic injury to the intestine during preservation remains an unresolved issue in transplantation medicine. Autophagy, a cytoplasmic protein degradation pathway, is essential for metabolic adaptation to starvation, hypoxia, and ischemia. It has been implicated in the cold ischemia (CI) of other transplantable organs. This study determines the changes in intestinal autophagy evoked by cold storage and explores the effects of autophagy on ischemic grafts. Cold preservation was simulated by placing the small intestines of Wistar rats in an IGL-1 (Institute George Lopez) solution at 4 °C for varying periods (3, 6, 9, and 12 h). The extent of graft preservation injury (mucosal and cellular injury) and changes in autophagy were measured after each CI time. Subsequently, we determined the differences in apoptosis and preservation injury after activating autophagy with rapamycin or inhibiting it with 3-methyladenine. The results revealed that ischemic injury and autophagy were induced by cold storage. Autophagy peaked at 3 h and subsequently declined. After 12 h of storage, autophagic expression was reduced significantly. Additionally, enhanced intestinal autophagy by rapamycin was associated with less tissue, cellular, and apoptotic damage during and after the 12-h long preservation. After reperfusion, grafts with enhanced autophagy still presented with less injury. Inhibiting autophagy exhibited the opposite trend. These findings demonstrate intestinal autophagy changes in cold preservation. Furthermore, enhanced autophagy was protective against cold ischemia-reperfusion damage of the small bowels.

Effect of Pioglitazone on endoplasmic reticulum stress regarding in situ perfusion rat model.

BACKGROUND: Ischemia-reperfusion injury (IRI) can cause insufficient microcirculation of the transplanted organ and results in a diminished and inferior graft survival rate. OBJECTIVE: This study aimed to investigate the effect of different doses of an anti-diabetic drug, Pioglitazone (Pio), on endoplasmic reticulum stress and histopathological changes, using an in situ perfusion rat model. METHODS: Sixty male Wistar rats were used and were divided into six groups, consisting of the control group, vehicle-treated group and four Pio-treated groups (10, 20, 30 and 40 mg/kg Pio was administered). The rats were perfused through vena cava and an outflow on the abdominal aorta occurred. Following the experiment, kidneys and livers were collected. The level of the endoplasmic reticulum stress markers (XBP1 and Caspase 12) was analyzed using Western blot and histopathological changes were evaluated. RESULTS: Histopathological findings were correlated with the Western blot results and depict a protective effect corresponding to the elevated dosage of Pioglitazone regarding in situ perfusion rat model. CONCLUSIONS: In our study, Pioglitazone can reduce the endoplasmic reticulum stress, and the most effective dosage proved to be the 40 mg/kg Pio referencing the kidney and liver samples.