Everolimus interferes with the inflammatory phase of healing in experimental colonic anastomoses

Update on Maintenance Immunosuppression in Intestinal Transplantation

Outcomes in intestinal transplantation remain hampered by higher rates of rejection than any other solid organs. However, maintenance immunosuppression regimens have largely remained unchanged despite advances in therapies for induction and treatment of rejection and graft-versus-host disease. Recently, there have been a small number of new maintenance therapies attempted, and older agents have been used in new ways to achieve better outcomes. The authors herein review the traditional maintenance therapies and their mechanisms and then consider updates in new therapies and new ways of using old therapies for maintenance immunosuppression after intestinal transplantation.

Basics and Art of Immunosuppression in Liver Transplantation

Liver transplantation is one of the most challenging areas in the medical field. Despite that, it has already been established as a standard treatment option, especially in decompensated cirrhosis and selected cases of hepatocellular carcinoma and acute liver failure. Complications due to graft rejection, including mortality and morbidity, have greatly improved over time due to better immunosuppressive agents and management protocols. Currently, immunosuppression in liver transplant patients makes use of the best possible combinations of effective agents to achieve optimal immunosuppression for long-term graft survival. Induction agents are no longer used routinely, and the aim is to provide minimal immunosuppression in the maintenance phase. Currently available immunosuppressive agents are mainly classified as biological and pharmacological agents. Though the protocols may vary among the centers and over time, the basics of effective use usually remain similar. Most protocols use the combination of multiple agents with different mechanisms of action to reduce the dose and minimize the side effects. Along with the improvement in operative and perioperative techniques, this art of immunosuppression has contributed to the recent progress made in the outcomes of liver transplants. In this review, we will discuss the various types of immunosuppressive agents currently in use, the different protocols of immunosuppression used, and the art of optimal use for achieving maximum immunosuppression without increasing toxicity. We will also discuss the practical aspects of various immunosuppression regimens, including drug monitoring, and briefly discuss the concepts of immunosuppression minimization and withdrawal.

Improvement of colonic healing and surgical recovery with perioperative supplementation of inulin and galacto-oligosaccharides

BACKGROUND AND AIMS

Anastomotic leak (AL) is a major complication in colorectal surgery. Recent evidence suggests that the gut microbiota may affect healing and may cause or prevent AL. Butyrate is a beneficial short-chain fatty acid (SCFA) that is produced as a result of bacterial fermentation of dietary oligosaccharides and has been described as beneficial in the maintenance of colonic health. To assess the impact of oligosaccharides on colonic anastomotic healing in mice, we propose to modulate the microbiota with oligosaccharides to increase butyrate production via enhancement of butyrate-producing bacteria and, consequently, improve anastomotic healing in mice.

METHODS

Animal experiments were conducted in mice that were subjected to diets supplemented with inulin, galacto-oligosaccharides (GOS) or cellulose, as a control, for two weeks before undergoing a surgical colonic anastomosis. Macroscopic and histological assessment of the anastomosis was performed. Extent of epithelial proliferation was assessed by Ki-67 immunohistochemistry. Gelatin zymography was used to evaluate the extent of matrix metalloproteinase (MMP) hydrolytic activity.

RESULTS

Inulin and GOS diets were associated with increased butyrate production and better anastomotic healing. Histological analysis revealed an enhanced mucosal continuity, and this was associated with an increased re-epithelialization of the wound as determined by increased epithelial proliferation. Collagen concentration in peri-anastomotic tissue was higher with inulin and GOS diets and MMP activity, a marker of collagen degradation, was lower with both oligosaccharides. Inulin and GOS diets were further associated with lower bacterial translocation.

CONCLUSIONS

Dietary supplementation with inulin and GOS may improve anastomotic healing and reinforce the gut barrier in mice.

Curcumin represses mTORC1 signaling in Caco-2 cells by a two-sided mechanism involving the loss of IRS-1 and activation of AMPK

The mechanistic target of rapamycin complex 1 (mTORC1) is a central modulator of inflammation and tumorigenesis in the gastrointestinal tract. Growth factors upregulate mTORC1 via the PI3K/AKT and/or Ras/MAPK signal pathways. Curcumin (CUR), a polyphenol found in turmeric roots (Curcuma longa) can repress mTORC1 kinase activity in colon cancer cell lines; however, key aspects of CUR mechanism of action remain to be elucidated including its primary cellular target. We investigated the molecular effects of physiologically attainable concentration of CUR (20 μM) in the intestinal lumen on mTORC1 signaling in Caco-2 cells. CUR markedly inhibited mTORC1 kinase activity as determined by the decreased phosphorylation of p70S6K (Thr389, -99%, P < 0.0001) and S6 (Ser235/236, -92%, P < 0.0001). Mechanistically, CUR decreased IRS-1 protein abundance (-80%, P < 0.0001) thereby downregulating AKT phosphorylation (Ser473, -94%, P < 0.0001) and in turn PRAS40 phosphorylation (Thr246, -99%, P < 0.0001) while total PRAS40 abundance was unchanged. The use of proteasome inhibitor MG132 showed that CUR-mediated loss of IRS-1 involved proteasomal degradation. CUR lowered Raptor protein abundance, which combined with PRAS40 hypophosphorylation, suggests CUR repressed mTORC1 activity by inducing compositional changes that hinder the complex assembly. In addition, CUR activated AMPK (Thr172 phosphorylation, P < 0.0001), a recognized repressor of mTORC1, and AMPK upstream regulator LKB1. Although cargo adapter protein p62 was decreased by CUR (-49%, P < 0.004), CUR did not significantly induce autophagy. Inhibition of AKT/mTORC1 signaling by CUR may have lifted the cross-inhibition onto MAPK signaling, which became induced; p-ERK1/2 (+670%, P < 0.0001), p-p38 (+1433%, P < 0.0001). By concomitantly targeting IRS-1 and AMPK, CUR's mechanism of mTORC1 inhibition is distinct from that of rapamycin.

Comparison of the Effects of Neostigmine and Sugammadex on Colonic Anastomotic Strength in Rats

BACKGROUND

After colorectal surgery, anastomotic leakage is a major cause of mortality and morbidity. There are many factors affecting anastomotic leakage. It is known that agents such as neostigmine that is used to reverse neuromuscular blockade have certain effects on anastomosis. In our study, in which we planned to test this hypothesis, we aimed to compare the possible effects of different doses of sugammadex and neostigmine on colon anastomosis strength in a colonic resection anastomosis model in rats.

MATERIALS AND METHODS

Forty adult Wistar albino male rats were divided into five groups as control (group C), Sugammadex 16 mg/kg (group SL), sugammadex 96 mg/kg (group SH), neostigmine 0.3 μmol/kg (group NL), and neostigmine 1.5 μmol/kg (group NH). The transverse colons of all rats were resected, and colonic anastomosis was performed. Appropriate drug doses according to the groups were given on the postoperative seventh day, and tissue hydroxyproline (TH) level and anastomotic bursting pressure were measured.

RESULTS

Anastomotic bursting pressure values were statistically significantly different between the groups (P = 0.001). The bursting pressure in group SH was significantly higher compared with group C, group NL, and group NH. The hydroxyproline values were statistically significantly different between the groups (P = 0.015). According to the post hoc test results, the difference was between group SH and group C (P = 0.007). There were no significant differences between the other groups (P > 0.05). There was no significant difference in terms of intra-abdominal adhesion rates between the groups.

CONCLUSIONS

In our study, we found that low and high doses of neostigmine had no variable effect on anastomosis, but high dose of sugammadex (96 mg/kg) had an increasing effect on intestinal anastomosis strength.

Ketorolac and Other NSAIDs Increase the Risk of Anastomotic Leakage After Surgery for GEJ Cancers: a Cohort Study of 557 Patients

OBJECTIVE

The objective of this study is to investigate the impact of ketorolac and other nonsteroidal anti-inflammatory drugs on anastomotic leakage after surgery for gastro-esophageal-junction cancer. Within the last two decades, the incidence of gastro-esophageal-junction cancer has increased in the western world and surgery is the curative treatment modality of choice. Anastomotic leakage is a feared complication of gastro-esophageal surgery, as it increases recurrence, morbidity, and mortality. Nonsteroidal anti-inflammatory drugs are widely used for postoperative pain relief. Nonsteroidal anti-inflammatory drugs have, however, in colorectal surgery, been shown to increase the risk of anastomotic leakage.

METHOD

In a historical cohort study, we investigated the impact of nonsteroidal anti-inflammatory drugs on anastomotic leakage in 557 patients undergoing surgery for gastro-esophageal-junction cancer. Data were collected from a prospective maintained database, the Danish National Patient Registry, and patient medical records. Data were analyzed using univariate and multivariate statistical models and were stratified for theoretical confounders.

RESULTS

In univariate analysis, we did not observe any difference in age, gender, tobacco exposure, or comorbidity status between patients experiencing anastomotic leakage and those without. In multivariate analysis, gender, histology, and type of anastomosis proved to affect odds ratios for anastomotic leakage. After adjustment for possible confounders, we found an odds ratio of 6.05 (95% confidence interval 2.71; 13.5) for ketorolac use and of 5.24 (95% confidence interval 1.85; 14.8) for use of other nonsteroidal anti-inflammatory drugs for anastomotic leakage during the first seven postoperative days.

CONCLUSION

In the present study, we found a strong association between the postoperative use of ketorolac and other nonsteroidal anti-inflammatory drugs and the risk for anastomotic leakage after surgery for gastro-esophageal-junction cancers.

Effect of thymoquinone on the healing of left colon anastomosis: an experimental study

Aim

To evaluate the effect of thymoquinone on the healing of experimental left colon anastomosis in rats.

Methods

Forty Wistar albino rats weighing 250–300 g were randomly divided into four groups (10 rats/group). Group 1 (control group) rats were not administered Thymoquinone (TQ) for 3 days after the operation. Group 2 was administered daily TQ for 3 days starting from the first day after the operation. Group 3 was not administered TQ for 7 days after the operation. Group 4 was administered daily TQ for 7 days starting from the first day after the operation. Thymoquinone was administered as a single dose oral gavage through a 4F feeding catheter per each day. The bursting strength of the anastomosis was measured on 3rd and 7th postoperative days (POD) and resection was performed. Subsequently, the hydroxyproline level in the resected tissue was measured and a histological evaluation was performed.

Results

The bursting pressures of the anastomoses were measured to be statistically significantly greater on 7th POD in TQ administered groups compared to those without TQ administration. Tissues were stained with Masson’s trichrome dye in order to evaluate the amount of fibrous tissue reaction for histopathological examination; there was no significant difference in the amount of fibrous tissue between groups 1 and 2, while a very marked increase in the fibrous tissue was detected in groups 3 and 4. Mean tissue hydroxyproline levels of the groups 3 and 4 on 7th POD were 1.30 and 2.72 μg/g-protein, respectively. The difference between the groups was statistically significant (p = 0.001).

Conclusions

TQ significantly increased the bursting pressure of the anastomosis, tissue hydroxyproline level, and fibrous tissue production.

Growth hormone abolishes the negative effects of everolimus on intestinal wound healing

AIM: To investigate whether the simultaneous treatment with human growth hormone (hGH) abolishes the negative effects of everolimus on anastomotic healing.

METHODS: Forty-eight male Sprague-Dawley-rats were randomized to three groups of 16 animals each (I: vehicle; II: everolimus 3 mg/kg po; III: everolimus 3 mg/kg po + hGH 2.5 mg/kg sc). Animals were pre-treated with hGH and/or everolimus daily for seven days. Then a standard anastomosis was created in the descending colon and treatment was continued for another seven days. The anastomosis was resected in toto and the bursting pressure was assessed as a mechanical parameter of intestinal healing. Moreover, biochemical (Hydroxyproline, PCNA, MPO, MMP-2 and MMP-9) and histological (cell density, angiogenesis, amount of granulation tissue) parameters of intestinal healing were assessed.

RESULTS: Anastomotic bursting pressure was significantly reduced by everolimus and a simultaneous treatment with hGH resulted in considerably higher values (I: 134 ± 19 mmHg, II: 85 ± 25 mmHg, III: 114 ± 25 mmHg; P < 0.05, I vs II; P = 0.09, I vs III and II vs III) Hydroxyproline concentration was significantly increased by hGH compared to everolimus alone (I: 14.9 ± 2.5 μg/mg, II: 8.9 ± 3.6 μg/mg, III: 11.9 ± 2.8 μg/mg; P < 0.05, I vs II/III and II vs III). The number of MPO-positive cells was reduced significantly by hGH compared to everolimus alone (I: 10 ± 1 n/mm², II: 15 ± 3 n/mm², III: 9 ± 2 n/mm²; P < 0.05, I vs II and II vs III), while the number of PCNA-positive cells were increased by hGH (I: 28 ± 3 /mm², II: 12 ± 3 /mm², III: 26 ± 12 /mm²; P < 0.05, I vs II and II vs III). Corresponding to these biochemical findings, HE-histology revealed significantly increased amount of granulation tissue in hGH-treated animals.

CONCLUSION: Inhibition of intestinal wound healing by everolimus is partially neutralized by simultaeous treatment with hGH. Both inflammation as well as collagen deposition is influenced by hGH.

Effects of bromopride on expression of metalloproteinases and interleukins in left colonic anastomoses: an experimental study

Anastomotic dehiscence is the most severe complication of colorectal surgery. Metalloproteinases (MMPs) and interleukins (ILs) can be used to analyze the healing process of anastomosis. To evaluate the effects of bromopride on MMP and cytokine gene expression in left colonic anastomoses in rats with or without induced abdominal sepsis, 80 rats were divided into two groups for euthanasia on the third or seventh postoperative day (POD). They were then divided into subgroups of 20 rats for sepsis induction or not, and then into subgroups of 10 rats for administration of bromopride or saline. Left colonic anastomosis was performed and abdominal sepsis was induced by cecal ligation and puncture. A colonic segment containing the anastomosis was removed for analysis of gene expression of MMP-1α, MMP-8, MMP-13, IL-β, IL-6, IL-10, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ). On the third POD, bromopride was associated with increased MMP-1α, MMP-13, IL-6, IFN-γ, and IL-10 gene expression. On the seventh POD, all MMP transcripts became negatively modulated and all IL transcripts became positively modulated. In the presence of sepsis, bromopride administration increased MMP-8 and IFN-γ gene expression and decreased MMP-1, TNF-α, IL-6, and IL-10 gene expression on the third POD. On the seventh POD, we observed increased expression of MMP-13 and all cytokines, except for TNF-α. In conclusion, bromopride interferes with MMP and IL gene expression during anastomotic healing. Further studies are needed to correlate these changes with the healing process.

Impact of perioperative immunosuppressive medication on surgical outcome in Crohn's Disease (CD)

INTRODUCTION

Patients with Crohn's disease [CD] carry an 80 - 90 % lifetime risk of undergoing surgery. Many of these patients are on immunosuppressive medication at the time of surgery. The aim of this study was to evaluate the effect of immunosuppression on the surgical outcome in CD patients.

METHODS

We retrospectively analyzed 484 consecutive abdominal operations for CD from 1995 to 2008 for surgical complications.

RESULTS

A total of 241 operations (= 49.8 %) were performed under perioperative immunosuppression (corticoids and thiopurine). The overall complication rate was 18.6 %, the major complication rate was 8.7 % and the anastomotic leakage rate was 3.3 %. No differences were observed between patients without immunosuppression compared to those with immunosuppression. Patients with colo-rectal resections showed a higher complication rate than patients with small bowel resection independently of immunosuppression.

CONCLUSION

Nearly 50 % of the patients undergoing abdominal surgery for CD are receiving immunosuppressive medication during surgery. However, perioperative immunosuppression with corticoids, thiopurine or the combination of both does not significantly alter the surgical complication rate. Therefore the decision of a required surgery should not be delayed due to the fact that the patient is under immunosuppressive medication.

Post-endoscopic retrograde cholangiopancreaticography complications in liver transplanted patients, a single-center experience

BACKGROUND

Complications in the biliary tract occur in 5%-30% after liver transplantation and the main part of the complications is successfully managed with endoscopic retrograde cholangiopancreaticography (ERCP). The incidence and risk factors for post-ERCP complications in liver transplantation patients are not well described. Our objective was to define the frequency of post-ERCP complications in liver transplantation patients at the Abdominal Center, Rigshospitalet, the only Liver Transplantation Center in Denmark.

METHODS

Retrospective study of all ERCPs performed in liver transplantation patients during a 9-year period.

RESULTS

A total of 292 ERCPs were included. Overall post-ERCP complications occurred in 24 procedures (8.2%): pancreatitis in 8 (2.7%), bleeding in 5 (1.7%), and cholangitis in 13 (4.5%) procedures. Simultaneous pancreatitis and cholangitis, and simultaneous bleeding and cholangitis occurred after two procedures, respectively. Multivariate analysis concerning overall complications identified biliary sphincterotomy (p = 0.006) and time since liver transplantation within 90 days postoperatively (p = 0.044) as risk factors for post-ERCP complications. Specifically concerning post-ERCP pancreatitis (PEP), it was found that pre-ERCP cholangitis was another independent risk factor for PEP (p = 0.026). Stent in the biliary tract prior to ERCP seemed to be protective (p = 0.041).

CONCLUSIONS

Complications were of surprisingly mild degree. The rates of post-ERCP complications in our study were in line with previous studies with liver transplantation patients. Cholangitis prior to ERCP may be another risk factor for post-ERCP pancreatitis.

Everolimus is a potent inhibitor of activated hepatic stellate cell functions in vitro and in vivo, while demonstrating anti-angiogenic activities

The present study demonstrates the therapeutic potential of everolimus for the treatment of hepatocellular carcinomas in the fibrotic liver by inhibiting hepatic stellate cell activation and angiogenesis.

Potential Therapeutic Roles for Inhibition of the PI3K/Akt/mTOR Pathway in the Pathophysiology of Diabetic Retinopathy

Novel therapeutics such as inhibitors of PI3K/Akt/mTOR pathway presents a unique opportunity for the management of diabetic retinopathy (DR). Second generation mTOR inhibitors have the prospect to be efficacious in managing various stages of disease progression in DR. During early stages, the mTOR inhibitors suppress HIF-1α, VEGF, leakage, and breakdown of the blood-retinal barrier. These mTOR inhibitors impart a pronounced inhibitory effect on inflammation, an early component with diverse ramifications influencing the progression of DR. These inhibitors suppress IKK and NF-κB along with downstream inflammatory cytokines, chemokines, and adhesion molecules. In proliferative DR, mTOR inhibitors suppress several growth factors that play pivotal roles in the induction of pathological angiogenesis. Lead mTOR inhibitors in clinical trials for ocular indications present an attractive treatment option for chronic use in DR with favorable safety profile and sustained ocular pharmacokinetics following single dose. Thereby, reducing dosing frequency and risk associated with chronic drug administration.

Everolimus-induced loss of wound strength can be prevented by a short postoperative delay in its administration

The use of mammalian target of rapamycin inhibitors coincides with an increased incidence of surgical complications. In previous experiments, serious negative effects of postoperative everolimus on anastomotic strength were found. This study aims to investigate if delayed drug administration can prevent loss of wound strength. Ten groups of Wistar rats each received daily oral doses of 1.0 or 2.0 mg/kg everolimus, starting the day of anastomotic construction in both ileum and colon, or 1, 2, 3, or 4 days later. The 11th group received saline. Seven days later, wound strength in anastomoses and in the abdominal wall and wound hydroxyproline levels were measured. Mean wound strength was significantly and dose-dependently reduced if everolimus was started on the day of operation. In ileum and colon, strength was not affected if drug administration was delayed until the third or second day, respectively. In abdominal fascia, this was the case only if everolimus was withheld until day 4. In general, changes in wound hydroxyproline content showed similarities to changes in wound strength. Thus, delaying administration of everolimus for 2-4 days after operation can prevent a serious loss of wound strength, both in the intestine and in the abdominal fascia.

Complications after ERCP in liver transplant recipients

BACKGROUND

Complications of the biliary tract after liver transplantation are successfully managed with ERCP; however, the incidence and risk factors for post-ERCP complications remain unknown.

OBJECTIVE

To examine the incidence, risk factors, and short-term outcome of post-ERCP complications in liver transplant (LT) recipients.

DESIGN

Retrospective evaluation of all ERCPs performed in LT recipients at our institution during a 7-year, 4-month period.

SETTING

Tertiary referral center.

PATIENTS

A total of 243 ERCPs performed in 121 LT recipients with duct-to-duct anastomosis.

MAIN OUTCOME MEASUREMENTS

Incidence of post-ERCP complications. Predictive factors were determined by univariate and multivariate analyses.

RESULTS

Overall complications occurred in 22 procedures (9%) (13 mild, 9 moderate): pancreatitis in 9 patients (3.7%), cholangitis in 8 patients (3.3%), postsphincterotomy bleeding in 4 patients (1.6%), and subcapsular hematoma in 1 patient (0.4%). The mean hospitalization for post-ERCP complications was 4.8 days (range 2-11 days). Logistic regression identified mammalian target of rapamycin inhibitors (odds ratio [OR], 4.65; 95% CI, 1.01-21.81; P = .049), serum creatinine level greater than 2 mg/dL (OR, 4.17; 95% CI, 1.07-16.26; P = .04), biliary sphincterotomy (OR, 3.03; 95% CI, 1.07-8.53; P = .037), and more than 2 pancreatic duct contrast injections (OR, 2.95; 95% CI, 1.10-7.91; P = .032) as independent risk factors for post-ERCP complications, whereas steroid therapy (OR, 0.23; 95% CI, 0.08-0.63; P = .004) was an independent protective factor.

LIMITATIONS

Single-center retrospective study.

CONCLUSIONS

The rate of complications after ERCP in LT recipients seems to be similar to that of non-LT recipients. Complications in this analysis were more common in LT recipients receiving mammalian target of rapamycin inhibitors and those with renal failure, biliary sphincterotomy, and more than 2 pancreatic duct injections, whereas they were less common in those patients on steroid therapy.