Effect of acute pancreatitis on porcine intestine: a morphological study.

AIM: The ultrastructural changes in the intestine were studied during experimental acute edematous and necrotizing porcine pancreatitis. The immunohistochemical expression of E-cadherin and ß-catenin in the jejunum and colon was assessed to characterize changes in the adherens junctions. METHODS: Twenty-four pigs were randomized to controls (n = 8) or to develop mild edematous (n = 8, saline infusion to pancreatic duct) or severe necrotizing pancreatitis (n = 8, taurocholic acid infusion). The ultrastructure of the mesenteric artery and the vein and epithelium of the jejunum and colon was analyzed at baseline and after 540 min with electron microscopy. The expression of E-cadherin and ß-catenin was assessed with immunohistochemistry. RESULTS: In the colon the microvilli and their glycocalyx shortened and reduced in density the most in necrotizing pancreatitis. In necrotizing pancreatitis adherens and tight junctions were occasionally open in the colon but rarely in the jejunum. Mitochondria in the colon epithelial cells were degenerated in necrotizing pancreatitis, swollen in edematous pancreatitis, and remained intact in the control case. In necrotizing pancreatitis, capillaries of the colon showed a broken endothelial lining with narrow lumens. The expression of E-cadherin immunoreactivity showed a trend toward a decrease in the colon in both edematous and necrotizing pancreatitis. CONCLUSION: Ultrastructural abnormalities in acute pancreatitis appear early in the colon, where they seem to be more damaging than in jejunum. Epithelial cell damage seems to include mitochondrial injury and an opening of tight and adherens junctions, which are more pronounced in necrotizing pancreatitis. Damage is seen in the mucosal and mesenteric endothelial cells.

Minimized and conventional cardiopulmonary bypass damage intestinal mucosal integrity.

OBJECTIVES: Previous studies have suggested that gastrointestinal integrity is compromised after cardiopulmonary bypass (CPB). We compared the effects of prolonged minimized (MCPB) and conventional CPB (CCPB) on intestinal mucosal integrity by determining mucosal damage, epithelial cell proliferation rate and distribution of tight junction proteins in a porcine model. DESIGN: Fourteen animals were randomly assigned to undergo 240 minutes of mild hypothermic MCPB or CCPB. Ileal and colonic biopsies were obtained prior and at the end of CPB. Mucosal damage was determined under light microscopic evaluation. Immunohistochemistry was used to investigate epithelial expression of Ki-67 as a measure of cell proliferation rate and claudin-1, 2, 3, 4, 5, and 7 as elements of tight junctions. RESULTS: In colonic biopsies, independent of the circuit type used, moderate mucosal damage was observed as indicated by focal epithelial damage, increased epithelial cell proliferation and decreased expression of tight junction protein claudin-4. CONCLUSIONS: Colonic mucosal damage was observed similarly in MCPB and CCPB. Based on these results, the effects of MCPB on intestinal mucosal stability are similar to those of CCPB.

Miniaturized versus conventional cardiopulmonary bypass in high-risk patients undergoing coronary artery bypass surgery.

OBJECTIVE: To review our results with the use of miniaturized cardiopulmonary bypass (Mini-CPB) versus conventional cardiopulmonary bypass (C-CPB) in high-risk patients (additive EuroSCORE>or=6) who have undergone coronary artery bypass graft surgery (CABG). PATIENTS AND METHODS: This study includes a consecutive series of 236 patients with an additive EuroSCORE>or=6 who underwent CABG, employing either C-CPB or Mini-CPB. Propensity score analysis was performed. RESULTS: The study groups had similar EuroSCOREs. Stroke rate was significantly higher among C-CPB patients (5.4% vs. 0%, p=0.026). In-hospital mortality (4.8% vs. 3.4%, p=0.75) and combined adverse end-point rate were higher in C-CPB patients (20.4% vs. 13.5%, p=0.18). Postoperative bleeding and need for transfusion were similar in the study groups, but re-sternotomy for bleeding was more frequent among C-CPB patients (4.8% vs. 1.1%, p=0.26). Seventy-four propensity matched pairs had similar immediate postoperative results: C-CPB patients had higher mortality (6.8% vs. 4.1%, p=0.72), stroke (5.4% vs. 0%, p=0.12) and combined adverse end-point rates (27.0% vs. 16.2%, p=0.11), but such differences failed to reach statistical significance. CONCLUSIONS: Mini-CPB achieved somewhat better results than C-CPB in these high-risk patients undergoing isolated CABG. This study confirmed that cerebral protection could be the main benefit associated with the use of Mini-CPB.

Minimized cardiopulmonary bypass reduces retinal microembolization: a randomized clinical study using fluorescein angiography.

BACKGROUND: The use of minimized cardiopulmonary bypass (MCPB) circuits has recently increased in an attempt to reduce the adverse effects of CPB. This prospective randomized study aimed to determine the effects of MCPB on retinal microembolization and related inflammatory, coagulation, and endothelial markers compared with conventional extracorporeal circulation (CCPB) among patients undergoing coronary artery bypass graft surgery. METHODS: Forty patients entered, and 37 patients completed the study. After the induction of anesthesia and immediately after the termination of CPB, standardized retinal fluorescein angiographs and digital images were obtained on both eyes and analyzed in a blinded fashion in terms of the CPB circuit. Blood samples for inflammatory, coagulation, and endothelial markers were collected at eight time points until the third postoperative day. RESULTS: Postperfusion retinal fluorescein angiographs revealed microembolic perfusion defects in 2 of 18 in the MCPB group and in 9 of 18 in the CCPB group (p=0.027 [11% vs. 50%, difference 39%, confidence interval: 0.087 to 0.613, p=0.029]). Activation of polymorphonuclear leukocytes as measured with polymorphonuclear elastase was significantly decreased in the MCPB group. Other markers of inflammation, coagulation, and endothelial dysfunction increased comparably in both groups during CPB. CONCLUSIONS: Retinal microembolization was found to be decreased after the use of minimized CPB compared with CCPB, suggesting a decreased embolic load to the brain after MCPB.