Different ischemic preconditioning regimens affecting preservation injury of intestines.

Decreasing ischemia-reperfusion injury in intestinal transplantation is of paramount importance for improving graft recovery and function. This study explores the ability of two ischemic preconditioning (IPC) regimens to reduce preservation injury. Sprague-Dawley rats were divided into 3 groups (n = 11 each). In the controls (group C), intestinal grafts were harvested and preserved. IPC was performed either through 4 cycles of mesenteric ischemia of 4 min each followed by 10 min of reperfusion (group BIPC) or 2 ischemic cycles of 12 min each followed by 10 min of reperfusion (group LIPC). Grafts were stored in histidine-tryptophan-ketoglutarate, and samples were taken 0, 3, 6, 9, 12, 18, and 24 h after preservation. Preservation injury was scored using the Park/Chiu scale. Goblet cells (GC), enteroendocrine cells (EEC) and serotonin-producing EEC (SPEEC) were studied for evaluation of the graft conditions. Group C had the most advanced preservation injury followed by group BIPC. GC count was lowest in group C, followed by BIPC. Comparison between groups BIPC and LIPC showed superior parameters (preservation injury, GC, EEC, and SPEEC) in LIPC. In conclusion, an IPC regimen of 2 ischemic cycles of 12 min each followed by 10 min of reperfusion distinctly decreased the preservation injury of intestinal grafts compared with non-manipulated grafts.

Morphological and apoptotic changes in the intestinal mucosa and lung parenchyma after ischaemic/reperfusion injury of the jejunum.

Ischaemic/reperfusion (IR) injury of the small intestine may lead to the development of multiple organ failure. Little is known about the morphological changes occurring in the organs during the subacute course of this syndrome. The objective of this study was to observe histopathological features and the role of apoptosis in the jejunal mucosa and lung parenchyma after intestinal IR injury in a long-term experiment. Wistar rats (n = 36) were divided into 4 experimental groups (IR(10), IR(20), IR(30), S). Groups IR(10), IR(20) and IR(30) (each n = 10) were subjected to 1-hour ischaemia of the cranial mesenteric artery followed by 10, 20 or 30 days of reperfusion, respectively. The control group S (n = 6) was not subjected to ischaemia. The jejunal mucosa remained intact after all periods of reperfusion. Apoptotic cells were found particularly in the lamina propria, with the most significant difference observed in the IR(30) group (P < 0.01). The lung parenchyma had lower regenerative capacity, which was confirmed by a high index of histological damage after 30 days of reperfusion (P < 0.01) and by the presence of an increased number of apoptotic cells, especially in the pulmonary interstitium. The number of apoptotic cells was ten times higher than in the control group (P < 0.001).

Development of jejunal graft damage during intestinal transplantation.

BACKGROUND: Intestinal transplantation (ITx) represents difficult life-saving intervention reserved for patients with irreversible intestinal failure. A serious complication of ITx is jejunal graft (JG) damage. The aim of the study was to evaluate the development of JG damage during ITx and determine the share of pathological elements (mechanical manipulation, ischemia, reperfusion) in this damage. MATERIAL/METHODS: Male Wistar rats (n=60; 30 donors and 30 recipients) were used. The harvest of JG as well as heterotopic allotransplantation was performed using a technique adapted from Balaz et al. (2003). In all transplantations, three samples of JG were obtained: immediately after harvest (Sa1), after preservation (Sa2) and 60min after transplantation (Sa3). The samples were stained using the Hematoxylin&Eosin method and histopathological injury index (HII) was assessed using Park/Chiu classification. For detection and quantification of neuroendocrine cells (NECs) Singh's modification of the Masson-Hamperl argentaffin technique was used. RESULTS: The lowest level of HII was detected in Sa1=0.25+/-0.18; higher after preservation Sa2=1.42+/-0.38 and the highest HII was observed after transplantation Sa3=3.08+/-0.38. The percentage share of mechanical manipulation with the graft in jejunal damage during ITx was 8.11% (Sa1), the share of the ischemic element represented 37.98% (Sa2) and reperfusion had 53.91% of the share in jejunal damage (Sa3). The activity of NECs had sinusoidal character (Sa1=0.5+/-0.1; Sa2=1.4+/-0.0; Sa3=0.35+/-0.05). CONCLUSIONS: The development of JG damage during ITx had progressive character. Mechanical manipulation had minimal influence on jejunal damage. One third of damage was caused by the ischemic component and the largest impact on JG damage resulted from reperfusion.

Serotonin levels in the small bowel mucosa as a marker of ischemic injury during small bowel preservation.

Of the serotonin occurring in the small bowel mucosa, 95% is present in enterochromaffine cells. The cold ischemia during small bowel transplantation results in mucosal injury and releasing of serotonin into the lumen. Because of it, the mucosal concentration of serotonin is decreasing. The aim of our study was to establish the correlation between changes in serotonin levels in small bowel mucosa during grafts preservation and cold ischemic time. Wistar rats (n= 35) weighing 322+/-18g, divided into five main groups (n= 7/group) according to the time of small bowel grafts preservation (0, 1, 6, 9, and 12 hours), were used as experimental animals. The grafts were preserved in 4 degrees C histidine-tryptophane-ketoglutarate (HTK) solution. Tissue samples for mucosal serotonin concentration measurement and for light microscopic evaluation were taken after predefined cold ischemic times. Quantitative histological assessment was made using the Park's small bowel wall injury grading scheme. The t-test for dependent samples was used for statistical analysis. The mean serotonin mucosal concentrations after 0, 1, 6, 9, and 12 hours of cold ischemic injury were 433.09+/-160.33, 402.6+/-120.53, 412.5+/-47.57 ng/mL, 190.8+/-45.88 and 145.2+/-16.78 ng/mL Statistically significant differences (p<0.05) were between 6, 9, and 12 hours of cold ischemia. Morphological changes of small bowel mucosa graded by Park's scheme after the same ischemic intervals were 0, 0.5+/-0.47, 0.97+/-0.41, 1.74+/-0.69, and 1.84+/-0.64. Statistically significant differences (p<0.05) were demonstrated between all preservation times except between 9 and 12 hours of cold ischemia. Morphological changes in small bowel mucosa correlated with cold ischemic time, as well as with serotonin mucosal concentration. These data indicate the possibility of use a serotonin concentration in small bowel mucosa as a parameter of small bowel grafts ischemic injury.