Cellular changes in hepatocytes and intestinal endothelium after hepatoduodenal ligament occlusion and protective effects of caspase inhibition

The Use of Newly Synthesized Composite Scaffolds for Bone Regeneration - A Review of Literature

At present, clamping of the portal triad is a widespread surgical procedure in hospitals. Such an operation can prevent pathological changes in the organs. However, the optimal time for clamping remains unclear. To determine the starting time of irreversible morphological changes in the small intestine due to the clamping of the portal triad. The study was carried out on rats (n=94). Animals were randomly subdivided into 4 groups based on the duration of clamping of the portal triad (PT): I control group (CG; without clamping the PT; n=10); II intervention group (6-IG; clamping PT for 6 min; n=28); III intervention group (12-IG; clamping time of the PT for 12 min; n=28); IV intervention group (24-IG; clamping time of the PT for 24 min; n=28). In groups 6- IG, 12-IG, 24-IG, after clamping the portal triad, animals were withdrawn from the experiment after 3 hours, 6 hours, 12 hours, 1 day, 3 days and 7 days. Morphological changes in the small intestine were assessed by measuring the diameter of the lumen of micro-vessels. In addition, the mortality in the groups was analysed as well. In the CG group, the diameter of the arterioles of the small intestine was 34±4 μm, the diameters of pre-capillaries were 15±2μm, the capillaries were 5.4±1 μm, the post-capillaries were 18±2 μm, and the diameter of the lumen of the venues was 40±3 μm. In the 6-IG group (on the 3rd day), the structure of the small intestine showed the recovery signs. By the 7th day, the indicators returned to their original values. In the 12-IG group, the parameters of the small intestine were restored on the seventh day that corresponds to the usual course of the disease. However, in the 24-IG group, changes in these organs persisted until the end of the study. No deaths were reported in the CG and 6-IG animal groups. Mortality among rats of the 12-IG group was 14.3%, while in the 24-IG group with PT clamping for 24 minutes it was 42.8%, respectively. The morphological changes in the microvasculature of the small intestine after 6-minute PT clamping showed a tendency to recover (back to the control parameters). Nevertheless, after 24 minutes of clamping, the changes in the intestinal tissue were irreversible.

Gut Barrier Dysfunction Induced by Aggressive Fluid Resuscitation in Severe Acute Pancreatitis is Alleviated by Necroptosis Inhibition in Rats

Fluid resuscitation is the first-line antishock treatment in severe acute pancreatitis (SAP). Currently, although mentions of complications related to aggressive fluid resuscitation are very frequent, a lack of proper handling of complications remains. One of the most important complications is intestinal barrier injury, including intestinal ischemia-reperfusion injury following aggressive fluid resuscitation. Once injured, the intestinal barrier may serve as the source of additional diseases, including systemic inflammatory response syndrome and multiple organ dysfunction syndrome, which aggravate SAP. This study focused on the underlying mechanisms of gut barrier dysfunction in rats induced by aggressive fluid resuscitation in SAP. This study further indicated the important role of necroptosis in intestinal barrier injury which could be relieved by using necroptosis-specific inhibitor Nec-1 before aggressive fluid resuscitation, thus reducing intestinal barrier damage. We also found pancreas damage after intestinal ischemia/reperfusion challenge and indicated the effects of high mobility group protein B1 in the vicious cycle between SAP and intestinal barrier damage.

Necroptosis is a key mediator of enterocytes loss in intestinal ischaemia/reperfusion injury

Cell death is an important biological process that is believed to have a central role in intestinal ischaemia/reperfusion (I/R) injury. While the apoptosis inhibition is pivotal in preventing intestinal I/R, how necrotic cell death is regulated remains unknown. Necroptosis represents a newly discovered form of programmed cell death that combines the features of both apoptosis and necrosis, and it has been implicated in the development of a range of inflammatory diseases. Here, we show that receptor-interacting protein 1/3 (RIP1/3) kinase and mixed lineage kinase domain-like protein recruitment mediates necroptosis in a rat model of ischaemic intestinal injury in vivo. Furthermore, necroptosis was specifically blocked by the RIP1 kinase inhibitor necrostatin-1. In addition, the combined treatment of necrostatin-1 and the pan-caspase inhibitor Z-VAD acted synergistically to protect against intestinal I/R injury, and these two pathways can be converted to one another when one is inhibited. In vitro, necrostatin-1 pre-treatment reduced the necroptotic death of oxygen-glucose deprivation challenged intestinal epithelial cell-6 cells, which in turn dampened the production of pro-inflammatory cytokines (tumour necrosis factor-α and interleukin-1β), and suppressed high-mobility group box-1 (HMGB1) translocation from the nucleus to the cytoplasm and the subsequent release of HMGB1 into the supernatant, thus decreasing the activation of Toll-like receptor 4 and the receptor for advanced glycation end products. Collectively, our study reveals a robust RIP1/RIP3-dependent necroptosis pathway in intestinal I/R-induced intestinal injury in vivo and in vitro and suggests that the HMGB1 signalling is highly involved in this process, making it a novel therapeutic target for acute ischaemic intestinal injury.

Variable Pringle Maneuvers and Effect on Intestinal Epithelium in Rats. A Pilot Experimental Study in Rats

BACKGROUND

It is observed that combined liver and colon surgery especially when this includes major liver resection with Pringle maneuver (PM) performance does not have a favorable outcome. Aim of our experimental study is to investigate the impact of portal triad occlusion on the large bowel and intra-abdominal inflammation and potent protective effects of the variants of (PM) in the combined surgical cases.

MATERIALS AND METHODS

Forty-four rats were divided into four groups. In group A (control group), 1cm of the left partial colon was resected and then an end-to-end anastomosis was performed. In group B, a continuous PM for 30 minutes was performed followed by resection of 1cm of the left colon and an end-to-end anastomosis. In group C, the left colonic resection and anastomosis was performed after intermittent PM (IPM), which was 10 minutes PM followed by 5 minutes reperfusion repeated for three circles. In group D, an ischemic preconditioning for 10 minutes was initially performed followed by 5 minutes reperfusion and then continuous PM for 30 minutes. Finally the rats in group D underwent a 1cm left colonic resection and an end-to-end anastomosis.

RESULTS

The percentage of colitis was higher in the B group (P = 0,19). The percentage of inflammation was not significantly higher even when we compared all "occlusion" groups (B+C+D) with the sham group. No evidence of pancreatitis was found in the sham group whereas amylase and lipase levels were higher in Groups B, C and D together (P = 0,0267). The comparison of group A to group B showed a significant difference (P = 0,0014) caused by continuous PM for 30 minutes, but there was no such result after IPM.

CONCLUSIONS

Major liver resections are performed with PM in order to minimize intra-operative blood loss. In the combined cases of colon surgery and major liver resections where PM is needed our results showed that IPM presents with better outcome and could be preferred compared with the other PM variants.

Intermittent clamping of the hepatic pedicle in simultaneous ultrasonography-guided liver resection and colorectal resection with intestinal anastomosis: is it safe?

PURPOSE

In patients with colorectal cancer (CRC) and synchronous colorectal liver metastases (CRLM) potentially candidates to combined liver (LR) and colorectal resection (CRR), the extent of LR and the need of hepatic pedicle clamping (HPC) in selected cases are considered risk factors for the outcome of the intestinal anastomosis. This study aimed to determine whether intermittent HPC is predictive of anastomotic leakage (AL) and has an adverse effect on the clinical outcome in patients undergoing combined restorative CRR and LR.

METHODS

One hundred six LR have been performed for CRLM in our unit from July 2005. Patients who received CRR with anastomosis and simultaneous intraoperative ultrasonography (IOUS)-guided LR/ablation for resectable CRLM were included in this study. CRR was performed first. Intermittent HPC was decided at the discretion of the liver surgeon. The perioperative outcome was evaluated according to occurrence of AL and overall postoperative morbidity and mortality.

RESULTS

Thirty-eight patients underwent simultaneous IOUS-guided LR/ablation and CRR with intestinal anastomosis; 19 underwent intermittent HPC (group ICHPY) while 19 did not (group ICHPN); the mean ± SD (range) duration of clamping in group ICHPY was 58.6 ± 32.2 (10.0-125.0) min. Postoperative results were similar between groups. One asymptomatic AL occurred in group ICHPY (5.2 %). Major postoperative complications were none in group ICHPY and one (5.2 %) in group ICHPN, respectively. One patient in group ICHPY died postoperatively (5.2 %).

CONCLUSIONS

This study suggests that intermittent HPC during LR is not predictive of AL and has no adverse effect on the overall clinical outcome in patients undergoing combined restorative colorectal surgery and hepatectomy for advanced CRC.

Total intermittent Pringle maneuver during liver resection can induce intestinal epithelial cell damage and endotoxemia

OBJECTIVES

The intermittent Pringle maneuver (IPM) is frequently applied to minimize blood loss during liver transection. Clamping the hepatoduodenal ligament blocks the hepatic inflow, which leads to a non circulating (hepato)splanchnic outflow. Also, IPM blocks the mesenteric venous drainage (as well as the splenic drainage) with raising pressure in the microvascular network of the intestinal structures. It is unknown whether the IPM is harmful to the gut. The aim was to investigate intestinal epithelial cell damage reflected by circulating intestinal fatty acid binding protein levels (I-FABP) in patients undergoing liver resection with IPM.

METHODS

Patients who underwent liver surgery received total IPM (total-IPM) or selective IPM (sel-IPM). A selective IPM was performed by selectively clamping the right portal pedicle. Patients without IPM served as controls (no-IPM). Arterial blood samples were taken immediately after incision, ischemia and reperfusion of the liver, transection, 8 hours after start of surgery and on the first post-operative day.

RESULTS

24 patients (13 males) were included. 7 patients received cycles of 15 minutes and 5 patients received cycles of 30 minutes of hepatic inflow occlusion. 6 patients received cycles of 15 minutes selective hepatic occlusion and 6 patients underwent surgery without inflow occlusion. Application of total-IPM resulted in a significant increase in I-FABP 8 hours after start of surgery compared to baseline (p<0.005). In the no-IPM group and sel-IPM group no significant increase in I-FABP at any time point compared to baseline was observed.

CONCLUSION

Total-IPM in patients undergoing liver resection is associated with a substantial increase in arterial I-FABP, pointing to intestinal epithelial injury during liver surgery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01099475.