Immunohistochemical study of jejunal graft mucosa cell populations during the initial adaptation phase in the host body in rats.

The character of the changes in cell populations within the jejunal graft mucosa during the initial adaptation phase in the host body was investigated. 24 adult male Wistar rats underwent intestinal heterotopic allotransplantation. Aorto-aortal and porto-caval anastomoses were performed using the end-to-side microsurgery technique. Graft tissues were compared to the intestinal tissues of the recipients. This study demonstrates that: (1) Distinct injury to the graft mucosa 1h after transplantation was accompanied by significant reduction in numbers of epithelial secretory cell populations. The injury was more intense in the mesenteric portion. Six hours after transplantation the graft mucosa was covered by a continuous epithelium, but the number of goblet and Paneth cells was found to be less than 30% of that in the recipient epithelium. (2) In comparison with recipients, myeloperoxidase-positive cell numbers increased significantly in the graft mucosa 1 h after transplantation. In the epithelial layer, denudation and destruction of villi was associated with a significant reduction in intraepithelial lymphocyte numbers. A significant decrease in mucosal mast cell numbers was detected 6 h after transplantation. They attained only 10% of the number found in the recipients. (3) Time-dependent changes in the graft mucosa revealed that CD163-positive cells increased significantly in the graft mucosa during 6 h after transplantation and reached the level found in the recipients. In contrast, the myeloperoxidase-positive cell population significantly decreased in the graft mucosa within the initial 6 h.

Intestinal ischemia-reperfusion injury - the histopathological status of remote vital organs in acute and subacute phases.

BACKGROUND: Improvement of graft recovery and function follows current trends in intestinal transplantation; however, the alteration of remote organs (RO) predicts complicated systemic rejection. This study was conceived to describe the histopathological status of RO arising in both acute and subacute stages after intestinal ischemia-reperfusion injury (IIR) injury. MATERIAL/METHODS: Wistar rats (n=54) were divided into 7 experimental groups (n=7 each). All the animals were subjected to 60 min mesenteric ischemia and subsequently to reperfusion 2 h, 4 h, 24 h, 72 h, 10 days, 20 days and 30 days following the groups IR2 h, IR4 h, IR24 h, IR72 h, IR10 d, IR20 d and IR30 d. As a control group (S; n=5) sham-operated animals were used. Histopathological scores (HPS) were evaluated in biopsies of the right kidney, heart and colon ascendens. RESULTS: Statistically significant increase in kidney HPS was seen during reperfusion, with the peak in IR4h group (p<0.01). Thereafter, improved morphology was observed; however, increased HPS was seen even in the subacute stage, and significant deterioration of HPS up to 10 days of reperfusion was detected (p<0.05). Heart biopsies also showed statistically increased HPS value in IR4h group (p<0.05). Intact morphology of the colon was detected in all reperfusion periods. CONCLUSIONS: IIR causes a systemic reaction affecting RO. The peak of alteration for kidney and heart morphology was induced by 60 min of ischemia followed by 4 h of reperfusion. Thereafter, improved morphology was observed, although latent persistence of histopathological changes was seen even in the subacute stage. The colon remained intact during the whole experiment despite its anatomical proximity, confirming its high immunological capacity.

Mesenteric ischemia-reperfusion injury: specific impact on different cell populations within the jejunal wall in rats.

The progress of jejunal damage and recovery in the course of mesenteric ischemia-reperfusion injury in rats at different time periods was investigated. Mesenteric ischemia lasting 1h followed by 1h of reperfusion caused a significant disintegration of the mucosa, reduction of the muscular layer and diminution of the wall thickness. The loss of epithelium included enterocytes, goblet cells and Paneth cells. Paradoxically, increasing numbers of serotonin-producing cells and the beginning of regenerative processes, expressed by significantly higher proliferation, were recorded in the epithelium during this period. Disintegration of connective tissue and massive degranulation of serotonin-positive cells were found in the lamina propria. After 24h of reperfusion, restitution of the mucosa was found, expressed by normal villous morphology and re-epithelialization. However, some parameters were still significantly affected even more than in the acute phase of reperfusion. In the epithelium, decreased numbers of Paneth cells and increased population of serotonin-producing cells were found. The greatest proliferation of connective tissue cells and intensified reduction of the muscular layer were also detected in this reperfusion period. After 30 days of reperfusion, moderate damage remained, but only the increased number of Paneth cells and decreased number of serotonin-producing cells in the lamina propria were significant.

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.