Neoadjuvant FOLFIRINOX versus upfront surgery for resectable pancreatic head cancer (NORPACT-1): a multicentre, randomised, phase 2 trial

BACKGROUND

In patients undergoing resection for pancreatic cancer, adjuvant modified fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) improves overall survival compared with alternative chemotherapy regimens. We aimed to compare the efficacy and safety of neoadjuvant FOLFIRINOX with the standard strategy of upfront surgery in patients with resectable pancreatic ductal adenocarcinoma.

METHODS

NORPACT-1 was a multicentre, randomised, phase 2 trial done in 12 hospitals in Denmark, Finland, Norway, and Sweden. Eligible patients were aged 18 years or older, with a WHO performance status of 0 or 1, and had a resectable tumour of the pancreatic head radiologically strongly suspected to be pancreatic adenocarcinoma. Participants were randomly assigned (3:2 before October, 2018, and 1:1 after) to the neoadjuvant FOLFIRINOX group or upfront surgery group. Patients in the neoadjuvant FOLFIRINOX group received four neoadjuvant cycles of FOLFIRINOX (oxaliplatin 85 mg/m2, irinotecan 180 mg/m2, leucovorin 400 mg/m2, and fluorouracil 400 mg/m2 bolus then 2400 mg/m2 over 46 h on day 1 of each 14-day cycle), followed by surgery and adjuvant chemotherapy. Patients in the upfront surgery group underwent surgery and then received adjuvant chemotherapy. Initially, adjuvant chemotherapy was gemcitabine plus capecitabine (gemcitabine 1000 mg/m2 over 30 min on days 1, 8, and 15 of each 28-day cycle and capecitabine 830 mg/m2 twice daily for 3 weeks with 1 week of rest in each 28-day cycle; four cycles in the neoadjuvant FOLFIRINOX group, six cycles in the upfront surgery group). A protocol amendment was subsequently made to permit use of adjuvant modified FOLFIRINOX (oxaliplatin 85 mg/m2, irinotecan 150 mg/m2, leucovorin 400 mg/m2, and fluorouracil 2400 mg/m2 over 46 h on day 1 of each 14-day cycle; eight cycles in the neoadjuvant FOLFIRINOX group, 12 cycles in the upfront surgery group). Randomisation was performed with a computerised algorithm that stratified for each participating centre and used a concealed block size of two to six. Patients, investigators, and study team members were not masked to treatment allocation. The primary endpoint was overall survival at 18 months. Analyses were done in the intention-to-treat (ITT) and per-protocol populations. Safety was assessed in all patients who were randomly assigned and received at least one cycle of neoadjuvant or adjuvant therapy. This trial is registered with ClinicalTrials.gov, NCT02919787, and EudraCT, 2015-001635-21, and is ongoing.

FINDINGS

Between Feb 8, 2017, and April 21, 2021, 77 patients were randomly assigned to receive neoadjuvant FOLFIRINOX and 63 to undergo upfront surgery. All patients were included in the ITT analysis. For the per-protocol analysis, 17 (22%) patients were excluded from the neoadjuvant FOLFIRINOX group (ten did not receive neoadjuvant therapy, four did not have pancreatic ductal adenocarcinoma, and three received another neoadjuvant regimen), and eight (13%) were excluded from the upfront surgery group (seven did not have pancreatic ductal adenocarcinoma and one did not undergo surgical exploration). 61 (79%) of 77 patients in the neoadjuvant FOLFIRINOX group received neoadjuvant therapy. The proportion of patients alive at 18 months by ITT was 60% (95% CI 49-71) in the neoadjuvant FOLFIRINOX group versus 73% (62-84) in the upfront surgery group (p=0·032), and median overall survival by ITT was 25·1 months (95% CI 17·2-34·9) versus 38·5 months (27·6-not reached; hazard ratio [HR] 1·52 [95% CI 1·00-2·33], log-rank p=0·050). The proportion of patients alive at 18 months in per-protocol analysis was 57% (95% CI 46-67) in the neoadjuvant FOLFIRINOX group versus 70% (55-83) in the upfront surgery group (p=0·14), and median overall survival in per-protocol population was 23·0 months (95% CI 16·2-34·9) versus 34·4 months (19·4-not reached; HR 1·46 [95% CI 0·99-2·17], log-rank p=0·058). In the safety population, 42 (58%) of 73 patients in the neoadjuvant FOLFIRINOX group and 19 (40%) of 47 patients in the upfront surgery group had at least one grade 3 or worse adverse event. 63 (82%) of 77 patients in the neoadjuvant group and 56 (89%) of 63 patients in the upfront surgery group had resection (p=0·24). One sudden death of unknown cause and one COVID-19-related death occurred after the first cycle of neoadjuvant FOLFIRINOX. Adjuvant chemotherapy was initiated in 51 (86%) of 59 patients with resected pancreatic ductal adenocarcinoma in the neoadjuvant FOLFIRINOX group and 44 (90%) of 49 patients with resected pancreatic ductal adenocarcinoma in the upfront surgery group (p=0·56). Adjuvant modified FOLFIRINOX was given to 13 (25%) patients in the neoadjuvant FOLFIRINOX group and 19 (43%) patients in the upfront surgery group. During adjuvant chemotherapy, neutropenia (11 [22%] patients in the neoadjuvant FOLFIRINOX group and five [11%] in the upfront surgery group) was the most common grade 3 or worse adverse event.

INTERPRETATION

This phase 2 trial did not show a survival benefit from neoadjuvant FOLFIRINOX in resectable pancreatic ductal adenocarcinoma compared with upfront surgery. Implementation of neoadjuvant FOLFIRINOX was challenging. Future trials on treatment sequencing in resectable pancreatic ductal adenocarcinoma should be biomarker driven.

FUNDING

Norwegian Cancer Society, South Eastern Norwegian Health Authority, The Sjöberg Foundation, and Helsinki University Hospital Research Grants.

Does the ypTNM-stage adequately predict long-term survival rates in gastric cancer patients receiving neoadjuvant chemotherapy followed by radical resection?

BACKGROUND

Following neoadjuvant chemotherapy (NAC) for resectable gastric cancer, the prognostic adequacy of the UICC staging system needs to be investigated. In particular to explore whether the ypTNM curves for radically resected gastric cancer patients receiving NAC follow the stage-matched survival curves of radically resected chemo-naïve patients (pTNM). Further, to disclose any interaction between the TNM-response mode to NAC and stage-specific survival rates, i.e., whether survival for a particular pathological disease stage was dependent on whether this was reached through a downstaging or as stable disease following NAC.

MATERIAL AND METHODS

Retrospective study on radically resected patients ≤ 75 years of age with gastric adenocarcinoma stages I-III diagnosed during 2001-2016. The patients constitute two population-based cohorts; the SURG-group with n = 121 patients treated before 2007 when NAC was introduced, and the NAC-group with n = 126 patients diagnosed since early 2007, receiving NAC and subsequent radical resection.

RESULTS

Long-term survival rates were similar when specific ypTNM-stages were compared to their corresponding pTNM chemo-naïve counterparts. The dichotomised N0 vs. N + had a substantial impact on the long-term survival rates in both groups, however, no discrepancy in long-term survival rates between pN0 vs. ypN0, and pN + vs. ypN + was found. The pathological stage determined long-term survival rates irrespective of the baseline disease stage, as no interaction between the response mode and stage-specific survival rates was found.

CONCLUSIONS

Survival curves for specific ypTNM-stages following NAC did not differ from the corresponding survival curves of their chemo-naïve pTNM counterparts. The interpretation is that NAC affected the gastric cancer, lymph nodes, and micrometastases, in such a way that the final ypTNM-stage provided similar prognostic information as the chemo-naïve pTNM-stages. Survival rates were contingent on the final ypTNM-stages alone, and not influenced by the response mode to reach that particular disease stage, or predetermined by the original clinical TNM-stage.

Cumulative incidence of first recurrence after curative treatment of stage I-III colorectal cancer. Competing risk analyses of temporal and anatomic patterns

BACKGROUND

Updated knowledge about the rates of recurrence and time to recurrence following curative treatment of colorectal cancer is essential to secure better patient information on prognosis, to serve as a premise in the discussion on adjuvant chemotherapy, and help to properly scale the intensity and length of follow-up.

METHODS

This is a population-based study investigating aspects on first recurrence after radical treatment of clinical stages I-III of colorectal cancer in Central-Norway during 2001-2015. To reveal any time-trends, data were stratified by the time periods 2001-2005, 2006-2010 and 2011-2015. The cumulative incidence of first recurrence was calculated, treating death of unrelated causes as a competing event. Multivariable Cox analyses were done to calculate cause specific hazard ratios (HR) for risk of recurrence.

RESULTS

At a minimum follow-up of six years, a first recurrence was detected in 1,113/5,556 patients at risk (20.0%). The recurrence rate was reduced from 23.6% in the first time period, through 20.0% in the second, and to 17.2% in the last, p < 0.001. The reduction applied to all tumor locations, to pathological disease stages II and III, to both gender, across different tumor differentiations, and to both elective and emergency surgery. In multivariable analyses time period, gender, disease stage, and tumor differentiation were significant determinants for risk of recurrence.

CONCLUSIONS

The rate of first recurrence after curative surgery for colorectal cancer was substantially reduced from 2001 to 2015. The reason for the reduction could not be attributed to a single factor only. A combined effect of several incremental improvements, such as an increased use of preoperative radiation for rectal cancers, improved adjuvant chemotherapy for colon cancer, and a reduced proportion of emergency surgery, is suggested.

Response Evaluation after Neoadjuvant Chemotherapy for Resectable Gastric Cancer

BACKGROUND

The method of response evaluation following neoadjuvant chemotherapy (NAC) in resectable gastric cancer has been widely debated. An essential prerequisite is the ability to stratify patients into subsets of different long-term survival rates based on the response mode. Histopathological measures of regression have their limitations, and interest resides in CT-based methods that can be used in everyday settings.

METHODS

We conducted a population-based study (2007-2016) on 171 consecutive patients with gastric adenocarcinoma who were receiving NAC. Two methods of response evaluation were investigated: a strict radiological procedure using RECIST (downsizing), and a composite radiological/pathological procedure comparing the initial radiological TNM stage to the pathological ypTNM stage (downstaging). Clinicopathological variables that could predict the response were searched for, and correlations between the response mode and long-term survival rates were assessed.

RESULTS

RECIST failed to identify half of the patients progressing to metastatic disease, and it was unable to assign patients to subsets with different long-term survival rates based on the response mode. However, the TNM stage response mode did achieve this objective. Following re-staging, 48% (78/164) were downstaged, 15% (25/164) had an unchanged stage, and 37% (61/164) were upstaged. A total of 9% (15/164) showed a histopathological complete response. The 5-year overall survival rate was 65.3% (95% CI 54.7-75.9%) for TNM downstaged cases, 40.0% (95% CI 20.8-59.2%) for stable disease, and 14.8% (95% CI 6.0-23.6%) for patients with TNM progression, p < 0.001. In a multivariable ordinal regression model, the Lauren classification and tumor site were the only significant determinants of the response mode.

CONCLUSIONS

Downsizing, as a method for evaluating the response to NAC in gastric cancer, is discouraged. TNM re-staging by comparing the baseline radiological CT stage to the pathological stage following NAC is suggested as a useful method that may be used in everyday situations.

Hypergastrinemia and mortality in gastric adenocarcinoma: a population-based cohort study, the HUNT study

Purpose: Hypergastrinemia increases the risk of developing proximal gastric adenocarcinoma. However, it is unclear if hypergastrinemia affects the survival in patients with gastric adenocarcinoma. This study aimed to examine the hypothesis that hypergastrinemia is associated with increased risk of mortality in patients with gastric adenocarcinoma.Materials and methods: This prospective population-based cohort study based on the Trøndelag Health Study (HUNT) included 78,962 adult individuals (≥20 years). During the baseline assessment period (1995-2008) of these participants, serum samples were collected and frozen. All participants with a newly diagnosed gastric adenocarcinoma in the cohort in 1995-2015 were identified and their gastrin levels were measured in the pre-diagnostic serum samples. Gastrin levels were analysed in relation to all-cause mortality until year 2020 using multivariable Cox regression providing hazard ratios (HRs) with 95% confidence intervals (CIs), adjusted for sex, age, body mass index (BMI), tobacco smoking, tumour stage, completeness of surgical resection, and peri-operative chemotherapy.Results: Among 172 patients with gastric adenocarcinoma, 81 (47%) had hypergastrinemia (serum gastrin >60 pmol/L) and 91 (53%) had normal gastrin level. The tumour location was proximal in 83 patients (43%) and distal in 78 (41%). Hypergastrinemia was not associated with any increased risk of all-cause mortality in all patients (adjusted HR 0.8, 95% CI 0.5-1.1), or in sub-groups of patients with proximal tumour location (HR 0.9, 95% CI 0.4-2.2) or distal tumour location (HR 0.9, 95% CI 0.5-1.7).Conclusion: This population-based cohort study indicates that hypergastrinemia may not increase the risk of mortality in patients with gastric adenocarcinoma.

Aspirin as secondary prevention in colorectal cancer liver metastasis (ASAC trial): study protocol for a multicentre randomized placebo-controlled trial

Background

Colorectal cancer is one the most common cancers in the western world with increasing incidence. Approximately 50% of the patients develop liver metastases. Resection of liver metastases is the treatment of choice although almost half of the resected patients get recurrence in the liver.

Methods

The ASAC trial is a Scandinavian, multicentre, double-blinded, randomized, placebo-controlled study to determine whether adjuvant treatment with low-dose aspirin (acetylsalicylic acid (ASA)) can improve disease-free survival in patients treated for colorectal cancer liver metastases (CRCLM). Up to 800 patients operated for CRCLM will be randomized to Arm#1 ASA 160 mg once daily or Arm#2 Placebo, for a period of 3 years or until disease recurrence. The patients will be recruited at all major hepatobiliary surgical units in Norway, Sweden and Denmark and have follow-up according to standard of care and the National Guidelines.

Discussion

The ASAC trial will be the first clinical interventional trial to assess the potential beneficial role of ASA in recurrence of CRCLM and survival. ASA is an inexpensive, well-tolerated and easily accessible drug that will be highly potential as adjuvant drug in secondary prevention of CRCLM if the study shows a beneficial effect. We will also determine the effect of ASA as adjuvant treatment on Health-Related Quality of Life and the cost-effectiveness.

Trial registration

ClinicalTrials.gov NCT03326791. Registered on 31 October 2017.

The value of restaging CT following neoadjuvant chemotherapy for resectable gastric cancer. A population-based study

Background

Response evaluation following neoadjuvant chemotherapy (NAC) in gastric cancer is debated. The aim of this study was to investigate the value of UICC-downstaging as mode of response evaluation following a MAGIC-style regimen of NAC.

Methods

Retrospective, population-based study on consecutive patients with resectable gastric adenocarcinoma receiving NAC from 2007 to 2016. CT-scan was obtained at diagnosis (rTNM) and repeated following NAC (yrTNM) to evaluate response in terms of downstaging. Further, yrTNM stage was crosstabulated to pathologic stage (ypTNM) to depict correlation between radiologic and pathologic assessment.

Results

Of 171 patients receiving NAC, 169 were available for response evaluation. For TNM-stages, 43% responded, 50% had stable disease and 7% progressed at CT. Crosstabulating yrTNM stage to ypTNM stage, 24% had concordant stages, with CT overstaging 38% and understaging 38% of the tumours, Cohen kappa ƙ = 0,06 (95%CI 0.004–0.12). Similar patterns of discordance were found for T-stages and N-stages separately. For M-category, restaging CT detected 12 patients with carcinomatosis, with an additional 14 diagnosed with carcinomatosis only at operation. No patient developed parenchymal or extra abdominal metastases, and none developed locally non-resectable tumour during delivery of NAC. Restaging CT with response evaluation was not able to stratify patients into groups of different long-term survival rates based on response mode.

Conclusions

Routine CT-scan following NAC is of limited value. Accuracy of CT staging compared to final pathologic stage is poor, and radiologic downstaging as measure of response evaluation is unreliable and unable to discriminate long-term survival rates based on response mode.

Computational Drug Repositioning and Experimental Validation of Ivermectin in Treatment of Gastric Cancer

Objective: The aim of the present study was repositioning of ivermectin in treatment of gastric cancer (GC) by computational prediction based on gene expression profiles of human and mouse model of GC and validations with in silico, in vitro and in vivo approaches.

Methods: Computational drug repositioning was performed using connectivity map (cMap) and data/pathway mining with the Ingenuity Knowledge Base. Tissue samples of GC were collected from 16 patients and 57 mice for gene expression profiling. Additional seven independent datasets of gene expression of human GC from the TCGA database were used for validation. In silico testing was performed by constructing interaction networks of ivermectin and the downstream effects in targeted signaling pathways. In vitro testing was carried out in human GC cell lines (MKN74 and KATO-III). In vivo testing was performed in a transgenic mouse model of GC (INS-GAS mice).

Results: GC gene expression “signature” and data/pathway mining but not cMAP revealed nine molecular targets of ivermectin in both human and mouse GC associated with WNT/β-catenin signaling as well as cell proliferation pathways. In silico inhibition of the targets of ivermectin and concomitant activation of ivermectin led to the inhibition of WNT/β-catenin signaling pathway in “dose-depended” manner. In vitro, ivermectin inhibited cell proliferation in time- and concentration-depended manners, and cells were arrested in the G₁ phase at IC₅₀ and shifted to S phase arrest at >IC₅₀. In vivo, ivermectin reduced the tumor size which was associated with inactivation of WNT/β-catenin signaling and cell proliferation pathways and activation of cell death signaling pathways.

Conclusion: Ivermectin could be recognized as a repositioning candidate in treatment of gastric cancer.

Neural signaling modulates metabolism of gastric cancer

Tumors comprise cancer cells and the associated stromal and immune/inflammatory cells, i.e., tumor microenvironment (TME). Here, we identify a metabolic signature of human and mouse model of gastric cancer and show that vagotomy in the mouse model reverses the metabolic reprogramming, reflected by metabolic switch from glutaminolysis to OXPHOS/glycolysis and normalization of the energy metabolism in cancer cells and TME. We next identify and validate SNAP25, mTOR, PDP1/α-KGDH, and glutaminolysis as drug targets and accordingly propose a therapeutic strategy to target the nerve-cancer metabolism. We demonstrate the efficacy of nerve-cancer metabolism therapy by intratumoral injection of BoNT-A (SNAP25 inhibitor) with systemic administration of RAD001 and CPI-613 but not cytotoxic drugs on overall survival in mice and show the feasibility in patients. These findings point to the importance of neural signaling in modulating the tumor metabolism and provide a rational basis for clinical translation of the potential strategy for gastric cancer.

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Metabolic reprogramming in gastric cancer cells and tumor microenvironment

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SNAP25, mTOR, PDP1/α-KGDH, and glutaminolysis as potential drug targets

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Combination of botulinum toxin type A, RAD001, and CPI-613 as a potential treatment

Hypergastrinemia is associated with an increased risk of gastric adenocarcinoma with proximal location: A prospective population-based nested case-control study

The incidence of proximal gastric adenocarcinoma is increasing among younger adults. Rodent models have shown that hypergastrinemia causes carcinogenesis in the proximal stomach. The aim of our study was therefore to assess if hypergastrinemia was associated with an increased risk of developing gastric adenocarcinoma also in humans. A prospective population‐based nested case‐control study within the Nord‐Trøndelag Health Study (HUNT) cohort, Norway, was used to assess this association. Serum was collected from 78 962 participants in 1995 to 1997 and 2006 to 2008. In the cohort, 181 incident gastric adenocarcinoma cases were identified from the Norwegian Cancer and Patient Registries through 2015 and matched with 359 controls. The risk of gastric adenocarcinoma was compared between participants with prediagnostic hypergastrinemia (>60 pmol/L) and normal serum gastrin (≤60 pmol/L). Logistic regression provided odds ratios (ORs) with 95% confidence intervals (CIs), adjusted for body mass index, tobacco smoking and comorbidity. Hypergastrinemia was associated with increased risk of gastric adenocarcinoma overall (OR 2.2, 95% CI 1.4‐3.4) and in particular for gastric adenocarcinoma with proximal location (OR 6.1, 95% CI 2.7‐13.8), but not with gastric adenocarcinoma with distal location (OR 1.7, 95% CI 0.9‐3.4). Moreover, hypergastrinemia was associated with an increased risk of gastric adenocarcinoma of intestinal histological type (OR 3.8, 95% CI 1.8‐7.9), but not for diffuse histological type (OR 1.6, 95% CI 0.7‐3.7). In conclusion, hypergastrinemia was associated with an increased risk of proximal and intestinal type gastric adenocarcinoma.

What's new?

The incidence of proximal gastric adenocarcinoma has been reported to increase among younger adults in Western countries. Rodent models have shown that serum gastrin levels above the normal range cause carcinogenesis in the proximal stomach. In this first prospective population‐based study on the association between hypergastrinemia and gastric adenocarcinoma, the risk of gastric adenocarcinoma in the proximal stomach, but not in the distal stomach, was markedly increased in hypergastrinemic individuals. The finding supports the hypothesis that hypergastrinemia mediates the development of gastric adenocarcinoma in the proximal stomach, where mucosal proliferation is stimulated by gastrin.

Impact of increased resection rates and a liver parenchyma sparing strategy on long-term survival after surgery for colorectal liver metastases. A population-based study

Background and aims: Expanded criteria for resection of colorectal liver metastases (CRLM) have led to a more aggressive surgical attitude. The aim is to evaluate any impact of expanded criteria on perioperative mortality and long-term survival. Materials and methods: A population based study from 2001 to 2015 for patients undergoing surgery for CRLM. The cohort was divided into three 5-year periods. Results: A total of 341 patients underwent resection of CRLM. Relative to the number of colorectal primaries, patients resected for CRLM increased from 82/2520 (3.3%) in 2001-2005 to 151/3071 (4.9%) in 2011-2015 (p = .007). The proportion of patients who underwent formal resections declined from 62% to 21%. There was a substantial increase in resections of synchronous liver metastases, portal vein embolizations, two-stage resections, and the share of octogenarians who underwent resection. The proportion of patients undergoing reresections of new liver recurrences increased from 6% to 24%. The 90-d postoperative mortality for 2001-2005, 2006-2010, and 2011-2015 were 7.9%, 0.8%, and 2.0%, respectively. The median overall survival was 47 months during the two first periods, for the last period not reached. The 5-year overall survival remained at 40% from 2001 to 2010, and estimated at 55.2% from 2011 to 2015. The 5-year disease-free survival was well above 30%. The 5-year overall survival following liver reresection was 52.6%. Conclusion: Postoperative mortality remained at approximately 2%, and the 5-year overall survival at 40% in the first 10 years, but increased to 55% in the last 5 years under study, despite a marked increase in resection rates.

Neoadjuvant chemotherapy versus surgery first for resectable pancreatic cancer (Norwegian Pancreatic Cancer Trial - 1 (NorPACT-1)) - study protocol for a national multicentre randomized controlled trial

Background

Pancreatic cancer is the fourth leading cause of cancer-related death. While surgical resection remains the foundation for potentially curative treatment, survival benefit is achieved with adjuvant oncological treatment. Thus, completion of multimodality treatment (surgical resection and (neo)adjuvant chemotherapy) to all patients and early treatment of micrometastatic disease is the ideal goal. NorPACT–1 aims to test the hypothesis that overall mortality at one year after allocation of treatment can be reduced with neoadjuvant chemotherapy in surgically treated patients with resectable pancreatic cancer.

Methods/Design

The NorPACT– 1 is a multicentre, randomized controlled phase III trial organized by the Norwegian Gastrointestinal Cancer Group for Hepato-Pancreato-Biliary cancer. Patients with resectable adenocarcinoma of the pancreatic head are randomized to receive either surgery first (Group 1: SF/control) or neoadjuvant chemotherapy (Group 2: NT/intervention) with four cycles FOLFIRINOX followed by resection. Both groups receive adjuvant chemotherapy with gemicitabine and capecitabine (six cycles in Group 1, four cycles in Group 2). In total 90 patients will be randomized in all the five Norwegian university hospitals performing pancreatic surgery. Primary endpoint is overall mortality at one year following commencement of treatment for those who ultimately undergo resection. Secondary endpoints are overall survival after date of randomization (intention to treat), overall survival after resection, disease-free survival, histopathological response, complication rates after surgery, feasibility of neoadjuvant and adjuvant chemotherapy, completion rates of all parts of multimodal treatment, and quality-of-life. Bolt-on to the study is a translational research program that aims at identifying factors that are predictive of response to NT, the risk of distant cancer spread, and patient outcome.

Discussion

NorPACT– 1 is designed to investigate the additional benefit of NT compared to standard treatment only (surgery + adjuvant chemotherapy) for resectable cancer of the pancreatic head to decrease early mortality (within one year) in resected patients.

Trial registration

Trial open for accrual 01.02.2017.

ClinicalTrials.gov Identifier: NCT02919787. Date of registration: September 14, 2016.

Abstract 1167: Inhibition of WNT/ß-catenin signaling-related glutamine metabolism but not the Warburg effect in denervation-induced suppression of gastric tumorigenesis

Background/aim: Cholinergic nerves have been shown to regulate gastric WNT/ß-catenin signaling in leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5)-positive stem cells and have recently been implicated in gastric tumorigenesis. Denervation by local vagotomy or botulinum neurotoxin type A injection or the muscarinic acetylcholine receptor 3 antagonist limit gastric cancer growth. The aim of this study was to further unravel the metabolic pathways underlying the vagotomy-induced suppression of gastric tumorigenesis.

Methods: Unilateral subdiaphragmatic truncal vagotomy (VT) was performed in wild-type (WT) and the INS-GAS mice, a genetic mouse model of spontaneous gastric cancer. Metabolic profiling and gene expression profiling in gastric tissues at 6 months post-surgery were performed using liquid chromatography/mass spectrometry, gas chromatography/mass spectrometry, high resolution magic angle spinning NMR spectroscopy, and microarray gene expression (Illumina).

Results: VT-induced suppression of tumorigenesis was manifested by reduced proliferation rate and increased apoptotic and autophagic signaling pathways, leading to reduced tumor size and prolonged survival. Principal component analysis showed four distinct clusters among 343 metabolic compounds: WT without VT, INS-GAS without VT, WT with VT and INS-GAS with VT. In the gastric tumor, the metabolic pathways that regulate stem cell homeostasis were downregulated after VT. Glutaminolytic pathway, including glutamine, glutamate, glycine and glutathione-S-S-glutathione, was down-regulated. The tricarboxylic acid cycle (TCA), including citrate, cis-aconitate, acetyle-CoA, threonine and glycine, was also down-regulated. However, glycolytic pathway, including glucose, glucose 6-phosphate, fructose 6-phosphate and lactate, was not significantly down-regulated. Signaling pathways that regulate glutamine metabolism, such as WNT/ß-catenin signaling, WNT target genes Cyclin D1, Axin2, Myc, Lgr5 and Cd44, p53 signaling, and mTOR signaling were down-regulated. The central carbon metabolism in cancer (“The Warburg effect” signaling) and lactate production were unchanged after VT. In addition, the choline metabolism, the lipid-derived eicosanoids and prostaglandins were reduced after VT.

Conclusions: The denervation-induced suppression of gastric tumorigenesis was associated with the inhibition of WNT/ß-catenin signaling-related glutamine metabolism but not the Warburg effect. We suggest that glutamine and choline phospholipid metabolisms can be used for metabolism-based tumor detection with MRS and/or positron emission tomography (PET) for gastric cancer diagnosis and that blocking these metabolic functions can be a therapeutic approach for gastric cancer treatment.

Citation Format: Gøran Andersen, Riyas Vettukattil, Yoku Hayakawa, Jon Erik Grønbech, Timothy C. Wang, Duan Chen, Chun Mei Zhao. Inhibition of WNT/ß-catenin signaling-related glutamine metabolism but not the Warburg effect in denervation-induced suppression of gastric tumorigenesis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1167. doi:10.1158/1538-7445.AM2015-1167

Impact of perioperative chemotherapy on oncological outcomes after gastric cancer surgery

BACKGROUND

Perioperative chemotherapy has become standard care for resectable gastric cancer. However, available evidence is based on a limited number of trials, and the outcomes in routine clinical practice and in unselected patients are scarcely reported.

METHODS

The study included a consecutive series of patients with resectable gastric cancer treated between 2001 and 2011 in Central Norway. Before 2007, patients with resectable gastric cancer did not receive perioperative chemotherapy. Since 2007, medically fit patients with resectable gastric cancer and aged 75 years or less have been offered this. Response rates were evaluated by CT, and tolerability was assessed by the frequency of hospital admission, need for dose reduction or treatment discontinuation. The two time intervals were compared on an intention-to-treat basis for patients aged no more than 75 years for any impact on resection rates, surgical morbidity, postoperative mortality and long-term survival.

RESULTS

About two-thirds (259) of the 419 patients registered were aged 75 years or less at diagnosis. Ninety-five of 136 patients in the later interval were eligible for chemotherapy, of whom 90 actually received the specified regimen, and 78 (87 per cent) were able to complete the preoperative course. Only 40 (44 per cent) completed all scheduled preoperative and postoperative cycles. Thirty-eight (43 per cent) of 89 evaluable patients showed a definite response on CT. Chemotherapy had no impact on postoperative morbidity or mortality. The 5-year survival rate on an intention-to-treat basis was 40·7 (95 per cent c.i. 30·7 to 50·7) per cent in the first interval, compared with 41·7 (31·5 to 51·9) per cent after the introduction of perioperative chemotherapy (P = 0·765). After adjustment for other risk factors, based on comparisons of the two time intervals, there were no differences in oncological outcomes with the use of perioperative chemotherapy.

CONCLUSION

Perioperative chemotherapy was completed in less than half of the patients with resectable gastric cancer. An observed tumour response to chemotherapy did not translate into any long-term survival benefit compared with surgery alone.

Regional distribution of blood flow during proximal aortic cross‐clamping: An experimental study using coloured microspheres

OBJECTIVE

To investigate the effect of thoracic aortic cross-clamping on blood perfusion of the brain, spinal cord, heart, muscular tissue and visceral organs.

MATERIAL AND METHODS

Nine pigs underwent 30 min cross-clamping of the descending thoracic aorta. Multiple coloured microspheres (15.0 microm +/- 0.1) were infused into the left ventricle before and during aortic cross-clamping (XC) and after declamping (DC). Tissue samples were analysed by spectrophotometry.

RESULTS

Blood perfusion of the middle and lower segments of the spinal cord was significantly reduced during aortic XC. Perfusion of the brain was not significantly altered by aortic XC, while perfusion of myocardium increased 3-fold. During XC, perfusion of the deltoid muscle and diaphragm increased 5-fold and 13-fold, respectively, while a decrease was found in the gluteus muscle. Renal blood flow was significantly reduced during XC. Finally, XC induced a significant decrease of perfusion in the bowel, spleen, liver and pancreas.

CONCLUSION

During XC of the thoracic aorta, the perfusion of the muscular tissue was significantly increased proximal to the level of XC. The circulation of the brain was unchanged, probably because of autoregulatory mechanisms. Blood perfusion of the myocardium increased 3-fold during XC.

Gut luminal lactate measured by microdialysis mirrors permeability of the intestinal mucosa after ischemia

The aim of the present study was to investigate the influence of a prolonged initial intestinal ischemic insult on transmucosal permeability after a subsequent ischemic event and whether microdialysis of biomarkers released to the gut lumen is able to reflect changes in intestinal permeability. The superior mesenteric artery was cross-clamped for 60 min followed by 4 h of reperfusion in 16 pigs. Nine pigs had a second cross-clamp of 60 min and 3 h of reperfusion, whereas seven pigs were observed for a further 4 h of reperfusion. Intestinal mucosal integrity was assessed by permeability of C-polyethylene glycol (PEG-4000) over the gut mucosa, luminal microdialysis of lactate, glucose and glycerol, and tonometry. During reperfusion, the PEG-4000 amount in venous blood was two times higher after the first than after the second ischemia (area under the curve, 44,780 [13,441-82,723] vs. 22,298 (12,213-49,698] counts min mL(-1), P=0.026 [mean {range}]). There was less lactate detected in the gut lumen after the second ischemia compared with the first (area under the curve, 797 [412-1,700] vs. 1,151 [880-1,969] mmol min L(-1), P=0.02) and a lower maximum concentration (4.8 [2.7-9.4] vs. 8.5 [5.0-14.9] mM, P=0.01). The same pattern was also seen for luminal glycerol and glucose. During the second ischemia, the intestinal mucosal/arterial CO2 gap was identical to the level during the first ischemic episode. A prolonged ischemic insult of the intestine confers protection, for reduced hyperpermeability against further ischemia. Microdialysis of biomarkers mirrors permeability changes associated with this type of protection. Lactate reflects permeability across the intestinal mucosa more precisely than glycerol.

[Surgical treatment of liver metastases from colorectal cancer]

BACKGROUND

The liver is the most common location for metastases from colorectal cancer. Current treatment options (i.e. neo-adjuvant chemotherapy, pre-operative portal vein embolization), IMPROVED OPERATIVE TECHNIQUES: and combinations of modalities and have rendered more patients eligible for liver surgery.

MATERIAL AND METHODS

Literature from 1996 to July 2007 was retrieved from Pubmed using the search terms "liver metastases", "liver resection", "colorectal cancer", "randomized controlled trial", "systematic review" and "meta-analysis".

RESULTS

No randomized controlled trials were identified that compared liver resection with non-surgical treatment of these patients. Except for a few systematic review articles, the scientific basis for resection of liver metastases from colorectal cancer consists mainly of retrospective studies from single institutions. Median survival for patients with colorectal liver metastases is about 20 months; a five-year survival of 30-50% is reported in resected patients. Patients with non-resectable disease rarely survive for five years. 30-40% of the resected patients have post-operative complications (mostly minor) and postoperative mortality is 3-5%.

INTERPRETATION

Surgical treatment of liver metastases is established practice. Patients with colorectal liver metastases should be referred to a multidisciplinary team for appropriate evaluation. Neoadjuvant treatment and multimodal approaches may increase the proportion of patients with resectable liver metastases, and better preoperative imaging may help to more carefully select patients who can benefit from this treatment.

Post-ischaemic restituted intestinal mucosa is more resistant to further ischaemia than normal mucosa in the pig

OBJECTIVE

Ischaemic preconditioning may protect the intestine from subsequent prolonged ischaemia. This study evaluates whether a much longer initial ischaemia, encountered clinically, may modify intestinal resistance to further ischaemia in a pig model.

MATERIAL AND METHODS

After cross-clamping of the superior mesenteric artery for 1 h, the intestine was either reperfused for 8 h or a second cross-clamping for 1 h was performed at 4 h of reperfusion. Based on microarray analysis of intestinal samples at 1, 4 and 8 h of reperfusion, mRNA of selected genes was measured with QRT-PCR.

RESULTS

The first ischaemic period caused exfoliation of surface epithelial cells from the basement membrane comprising about 90 % of the villi tips, a marked increase in permeability and depletion of ATP. The second ischaemic challenge caused about 30 % less denudation of the basement membrane (p = 0.008), no increase in permeability (p = 0.008) and less depletion of ATP (p = 0.039). mRNAs for superoxide dismutase 2, heat shock proteins and signal transducer and activator of transcription 3, which may protect against ischaemia/reperfusion injury, were up-regulated throughout the reperfusion period. mRNAs for matrix metalloproteinase 1, connexin 43 and peripheral myelin 22, which may be associated with cell migration or tight junctions, showed a particular up-regulation at 4 h of reperfusion.

CONCLUSION

One hour of initial ischaemia followed by 4 h of reperfusion is associated with increased intestinal resistance to further ischaemia. The differential regulation of genes identified in this study provides working hypotheses for mechanisms behind this observation.

Lactate and glycerol released to the intestinal lumen reflect mucosal injury and permeability changes caused by strangulation obstruction

BACKGROUND

The present study evaluates whether microdialysis of glycerol and lactate reflects mucosal injury and permeability changes after strangulation obstruction of the pig small intestine.

METHODS

Strangulation obstruction was induced by tightening a rubber band around a small bowel loop until its venous pressure increased to a level just below diastolic aortic pressure (partial strangulation), or further until cessation of flow in the main feeding artery (total strangulation). Mucosal injury and permeability of marker molecules from blood to lumen and vice versa was compared to release of glycerol and lactate to the intestinal lumen.

RESULTS

Mucosal injury, hyperpermeability, and release of glycerol were more pronounced after total than after partial strangulation. In animals with partial strangulation there was a complete restitution of the surface epithelium, and luminal glycerol and lumen-to-blood permeability of polyethylene glycol 4000 remained low. Such animals showed a sustained elevation of lactate and blood-to-lumen permeability of fluorescein isothiocyanate dextran after 2 h of partial strangulation, but a decline to baseline levels of these parameters in animals with 1 h partial strangulation.

CONCLUSION

Microdialysis of lactate and glycerol in the intestinal lumen may be used to assess structural and functional changes of the intestinal mucosa after strangulation obstruction.

Rectal lactate levels in endoluminal microdialysate during routine coronary surgery

The aim of this prospective study was to determine the feasibility of intestinal endoluminal microdialysis as a new method for clinical monitoring of the adequacy of splanchnic perfusion in the large bowel. A microdialysis catheter for continuous lactate, glycerol, glucose and pyruvate measurements attached to a tonometric catheter was placed into the lumen of the recto-sigmoid junction prior to surgery in 13 patients undergoing elective cardiac surgery with cardiopulmonary bypass (CPB). Lactate was also measured in blood and muscle. CPB was associated with a 10-fold increase in luminal lactate from 0.16 (0.01) to 1.67 (0.38) mmol x l(-1) (p < 0.001). Muscular lactate increased from baseline levels 1.20 (0.21) to 1.77 (0.36) mmol x l(-1) during CPB (p = 0.01), but the muscular lactate-pyruvate ratio remained unchanged. Arterial lactate increased only slightly from 0.9 (0.05) to 1.1 (0.06) mmol x l(-1) (p = 0.027) during CPB. Increased lactate concentrations in the large bowel during CPB are suggestive of local lactate production consistent with impaired oxygen delivery. Intestinal endoluminal microdialysis is a potential clinically applicable method for monitoring intestinal metabolism. Combined with tonometry, microdialysis provides the opportunity to monitor both circulation and metabolism in the rectal mucosa.

Hemodynamic and tissue blood flow responses to long-term pneumoperitoneum and hypercapnia in the pig

BACKGROUND

Increased peritoneal blood flow may influence the ability of cancer cells to adhere to and survive on the peritoneal surface during and after laparoscopic cancer surgery. Carbon dioxide (CO2) pneumoperitoneum is associated with a marked blood flow increase in the peritoneum. However, it is not clear whether the vasodilatory effect in the peritoneum is related to a local or systemic effect of CO2.

METHODS

In this study, 21 pigs were exposed to pneumoperitoneum produced with either CO2 (n = 7) or helium (He) (n = 7) insufflation at 10 mmHg for 4 h, or to two consecutive levels of hypercapnia (7 and 11 kPa) (n = 7) produced by the addition of CO2 to the inhalational gas mixture. Tissue blood flow measurements were performed using the colored microsphere technique.

RESULTS

Blood flow in peritoneal tissue increased during CO2, but not He, pneumoperitoneum, whereas it did not change at any level of hypercapnia alone. There was no change in blood flow in most organs at the partial pressure of CO2 (PaCO2) level of 7 kPa. However, at a PaCO2 of 11 kPa, blood flow was increased in the central nervous system, myocardium, and some gastrointestinal organs. The blood flow decreased markedly in all striated muscular tissues during both levels of hypercapnia.

CONCLUSION

The effect of CO2 on peritoneal blood flow during laparoscopic surgery is a local effect, and not attributable to central hemodynamic effects of CO2 pneumoperitoneum or high systemic levels of CO2.

ECL cell histamine mobilization and parietal cell stimulation in the rat stomach studied by microdialysis and electron microscopy

AIM

Gastrin stimulates acid secretion by mobilizing histamine from enterochromaffin-like (ECL) cells that occur predominantly at the base of the gastric glands. The parietal cells occur higher up in the glands nearer to the gastric lumen. The present study was performed to assess whether histamine is transported from the ECL cell via the microcirculation (endocrine route) or local diffusion (paracrine route).

METHODS

Totally isolated, vascularly perfused, rat stomachs were examined both in basal and gastrin-stimulated state. Histamine concentrations, determined by radioimmunoassay in venous effluent and microdialysate from an indwelling probe in the submucosa, were monitored over a period of 240 min. Gastrin-17 was infused through an arterial catheter for 120 min. The parietal cells were examined by electron microscopy, and the percentage of actively secreting parietal cells (displaying secretory canaliculi) in four regions along the glands (basal to surface, zones I-IV) was determined.

RESULTS

Gastrin stimulated acid secretion and histamine release as well as parietal cell activation. Upon gastrin stimulation, histamine concentration in the microdialysate was 2.5-fold higher than in the venous effluent (P = 0.008). The parietal cells in the upper part of the gland (zone III) were found to be activated the most.

CONCLUSION

As the histamine concentrations were higher in the tissue (microdialysate) than in blood, histamine seems to reach the parietal cells via the paracrine route. The fraction of active parietal cells seems to depend more on the age of the parietal cells than on the distance from the ECL cell.

Gut luminal microdialysis of glycerol as a marker of intestinal ischemic injury and recovery

OBJECTIVE

To evaluate microdialysis as a method to assess different degrees of intestinal damage and recovery during ischemia and reperfusion; to evaluate information obtained from microdialysis catheters in the peritoneum, the gut wall, and the gut lumen.

DESIGN

Randomized, controlled animal experiment.

SETTING

University laboratory animal center.

SUBJECTS

Twenty-seven domestic pigs.

INTERVENTIONS

The superior mesenteric artery was cross-clamped for 60 mins (n = 14) or 120 mins (n = 10) followed by 2 or 4 hrs of reperfusion. Three pigs served as controls.

MEASUREMENTS AND MAIN RESULTS

Intestinal mucosal integrity was assessed by morphometry, adenosine triphosphate in the gut wall, and permeability of C-polyethylene glycol. Lactate, glycerol, pyruvate, and glucose were measured by microdialysis. Changes in adenosine triphosphate, permeability, or lactate did not correlate to different extents of intestinal damage caused by 60 or 120 mins of ischemia. During the reperfusion period, pigs with 60 mins of intestinal ischemia showed a faster recovery of these variables than pigs with 120 mins of intestinal ischemia. Glycerol increased with increasing duration of the ischemic insult. After 60 mins of intestinal ischemia, glycerol in the gut lumen decreased toward baseline but remained high after 120 mins of intestinal ischemia. There was a good correlation between gut luminal glycerol and recovery of mucosal damage throughout the reperfusion period. In the peritoneal cavity, both glycerol and lactate decreased to baseline relatively shortly after onset of reperfusion independent of the duration of intestinal ischemia.

CONCLUSIONS

Microdialysis of glycerol provides information about the extent and severity of intestinal damage after ischemia and about the ensuing recovery. The gut lumen is to be preferred as a site for placement of microdialysis catheters.

Role of bradykinin in gastric vasodilation caused by hypertonic saline and acid back diffusion

Protective vasodilation in response to tissue injury and acid back diffusion is associated with release of bradykinin in the rat stomach. We hypothesized that bradykinin might be involved in mechanisms behind such vasodilation via influence on mast cells and sensory neurons. Acid back diffusion after mucosal barrier disruption with hypertonic saline evoked degranulation of mast cells in the rat stomach wall. Acid back diffusion was also associated with increased luminal release of histamine and gastric blood flow in normal rats, but not in mast cell-deficient rats. Bradykinin (BK(2)) receptor blockade inhibited degranulation of submucosal mast cells in the stomach and attenuated gastric vasodilation both in response to acid back diffusion and after stimulation of sensory neurons with capsaicin. Gastric vasodilation caused by mucosal injury with hypertonic saline alone was associated with degranulation of mucosal mast cells. These events were unaffected by inhibition of prostaglandin synthesis, whereas bradykinin (BK(2)) receptor blockade was associated with abolished vasodilation and inhibition of mucosal mast cell degranulation. We conclude that bradykinin is involved in gastric vasodilation caused by hypertonic injury alone via influence on mast cells, and by acid back diffusion via influence on both sensory neurons and mast cells.

Intestinal injury after thoracic aortic cross-clamping in the pig

BACKGROUND

The mucosal surface epithelium is an essential part of the functional intestinal barrier, but its structural response to ischemia/reperfusion is only partly characterized. The purpose of this study was to provide a detailed morphological evaluation of intestinal surface epithelium after aortic cross-clamping.

MATERIAL AND METHODS

Pigs were subjected to thoracic aortic cross-clamping for 60 min and subsequent reperfusion for 120 min. Tissue blood flow and high-energy phosphates were measured with microspheres and HPLC, respectively. Urinary excretion of (14)C polyethylene glycol (MW 4000 Da) (PEG-4000), loaded into an intestinal loop, provided an index of intestinal permeability.

RESULTS

Jejunal blood flow was restored at 10 min after aortic declamping. Denudation of the basement membrane of the intestinal villi tips, as a consequence of epithelial shedding, increased markedly during the initial 60 min of reperfusion (P = 0.002). During the following 45 min, the denuded basement membrane was partly covered with low cuboidal and squamous-shaped cells extending lamellipodia over a wavy basement membrane. Restoration of ATP at 60 min after aortic declamping correlated inversely to the extent of denuded basement membrane (r = 0.75, P = 0.032). Permeability of PEG-4000 increased markedly after aortic declamping and was linearly correlated to the area of denuded basement membrane (r = 0.87, P = 0.01).

CONCLUSIONS

Reperfusion for 2 h after aortic cross-clamping is associated with initial aggravation of ischemia-induced injury in the porcine jejunum, but thereafter with restitution of the surface epithelium. Restoration of ATP may be important to avoid intestinal injury after ischemia. Increased permeability of a macromolecule in response to reperfusion is closely correlated to injury of the surface epithelium.

Gut barrier dysfunction as detected by intestinal luminal microdialysis

OBJECTIVE

To evaluate the use of gut luminal microdialysis as a tool for monitoring ischaemic metabolites, particularly glycerol, as markers of intestinal dysfunction during and after intestinal ischaemia.

DESIGN

A randomised, controlled animal experiment.

SETTING

National laboratory animal centre.

INTERVENTIONS

In seven pigs the thoracic aorta was cross-clamped for 60 min followed by 2 h of reperfusion, while five pigs served as controls.

MEASUREMENTS AND RESULTS

Glycerol, lactate and glucose in the intestinal lumen and mucosa were measured by microdialysis. Intestinal tissue blood flow was determined by means of colour-labelled microspheres. To assess intestinal permeability, (14)C-polyethylene glycol 4000 (PEG-4000) was instilled in a jejunal segment and then measured in venous blood. Intestinal blood flow was reduced to 10% of baseline by aortic cross-clamping ( p=0.001) and returned to baseline during reperfusion. Intestinal luminal lactate increased during ischaemia and further increased during reperfusion. The increase was paralleled by augmented intestinal permeability; there was a significant correlation between luminal lactate and venous PEG-4000 ( r=0.89, p<0.01). Aortic cross-clamping caused a marked increase in intestinal mucosal glycerol concentrations, which correlated with luminal glycerol during both ischaemia and reperfusion ( r=0.85, p<0.01).

CONCLUSION

Microdialysis of lactate may be useful for monitoring intestinal ischaemia and reperfusion. Release of lactate into the intestinal lumen appears to be related to increased permeability. Intestinal luminal glycerol closely mirrored glycerol concentrations in the intestinal wall.

Effect of carbon dioxide pneumoperitoneum on tissue blood flow in the peritoneum, rectus abdominis, and diaphragm muscles

BACKGROUND

Changes in local blood flow may play a role in the pathogenesis of port-site metastasis. This study aimed to investigate the effect of pneumoperitoneum induced by carbon dioxide (CO2) on the blood flow in the peritoneum and abdominal wall muscle layers, which are target structures for this phenomenon.

METHODS

The study was performed on domestic farm swine of both genders weighing 20 to 25 kg. Intraabdominal pressures (IAP) of 0, 5, and 10 mmHg were produced by either CO2 ( n = 9) or helium (He) ( n = 6) insufflations. The colored microsphere technique was used to measure blood flow distributions in the parietal peritoneum, rectus abdominis, and diaphragm muscles.

RESULTS

Insufflation of CO2 was associated with a threefold increase in blood flow of the parietal peritoneum at both 5 and 10 mmHg IAP ( p < 0.001 for both pressure levels). In contrast, insufflation of He caused a significant decrease in blood flow in the parietal peritoneum at both 5 and 10 mmHg ( p < 0.05). In the rectus abdominis and diaphragm muscles, blood flow remained unchanged after insufflation of CO2 at both 5 and 10 mmHg IAP. However, after insufflation of He, there was a substantial decrease in blood flow both in the rectus abdominis and diaphragm muscles at both 5 mmHg ( p < 0.01 and p < 0.05, respectively) and 10 mmHg ( p < 0.001 and p < 0.01, respectively).

CONCLUSIONS

Despite high intraabdominal pressure, tissues surrounding the abdominal cavity, particularly the peritoneum, respond to insufflation of CO2 with increased blood flow, which may favor the growth of tumor cells.

Histamine is involved in gastric vasodilation during acid back diffusion via activation of sensory neurons

Protective vasodilation during acid back diffusion into the rat gastric mucosa depends on activation of sensory neurons and mast cell degranulation with histamine release. We hypothesized that these two mediator systems interact and that histamine partly exerts its effect via sensory nerves. Gastric blood flow (GBF) and luminal histamine were measured in chambered stomachs, and mast cell numbers were assessed by morphometry. Ablation of sensory neurons and depletion of mast cells were produced by pretreatment with capsaicin or dexamethasone, respectively. Mucosal exposure to 1.5 M NaCl and then to pH 1.0 saline in ablated and control rats caused increased luminal histamine and reduced numbers of mast cells. Enterochromaffin-like cell marker pancreastatin remained unchanged. Only control rats responded with an increase in GBF. Capsaicin stimulation (640 microM) of the undamaged mucosa induced identical increase in GBF and unchanged mast cell mass in normal and dexamethasone-treated rats. Increase in GBF after topical exposure to histamine (30 mM) in rats pretreated with capsaicin or a calcitonin gene-related peptide (CGRP)(1) antagonist human CGRP(8-37) or exposed to the calcium pore blocker ruthenium red was less than one-half of that in control rats. These data suggest that mast cell-derived histamine is involved in gastric vasodilatation during acid back diffusion partly via sensory neurons.

Mast cells are involved in the gastric hyperemic response to acid back diffusion via release of histamine

Acid back diffusion into the rat stomach mucosa leads to gastric vasodilation. We hypothesized that histamine, if released from the rat mucosa under such conditions, is mast cell derived and involved in the vasodilator response. Gastric blood flow (GBF) and luminal histamine were measured in an ex vivo chamber. Venous histamine was measured from totally isolated stomachs. Mucosal mast cells (MMC), submucosal connective tissue mast cells (CTMC), and chromogranin A-immunoreactive cells (CgA IR) were assessed morphometrically. After mucosal exposure to 1.5 M NaCl, the mucosa was subjected to saline at pH 5.5 (control) or pH 1.0 (H(+) back diffusion) for 60 min. H(+) back diffusion evoked a marked gastric hyperemia, increase of luminal and venous histamine, and decreased numbers of MMC and CTMC. CgA IR cells were not influenced. Depletion of mast cells with dexamethasone abolished (and stabilization of mast cells with ketotifen attenuated) both hyperemia and histamine release in response to H(+) back diffusion. GBF responses to H(+) back diffusion were attenuated by H(1) and abolished by H(3) but not H(2) receptor blockers. Our data conform to the idea that mast cells are involved in the gastric hyperemic response to acid back diffusion via release of histamine.

Effect of increased intraabdominal pressure on cardiac output and tissue blood flow assessed by color-labeled microspheres in the pig

BACKGROUND

Studies of the hemodynamic effects associated with the pneumoperitoneum have had controversial results. We set out to investigate the effect of increased intraabdominal pressure (IAP) on cardiac output and tissue blood flow in various intraabdominal and extraabdominal organs using the color-labeled microsphere (CLM) technique.

METHODS

IAP was induced by CO2 insufflation in anesthetized pigs; 0, 5, and 10 mmHg was used in the low-pressure group and 0, 15, and 24 mmHg in the high-pressure group. Tissue blood flow (ml.min-1.g-1) and cardiac output (CO) (ml/min) were determined by the CLM technique.

RESULTS

CO decreased at IAP > or = 15 mmHg. Arterial PaCO2 and hydrogen ion concentration increased in response to all levels of IAP. Arterial PaO2, oxygen saturation, and bicarbonate ion concentration remained unchanged. Low IAP did not influence tissue blood flows in most of the organs. However, in the spleen, pancreas, esophagus, and gastric mucosal specimens, tissue blood flow was significantly decreased at 24 mmHg.

CONCLUSION

The level of IAP used in current practice (10-12 mmHg) appears to be safe with regard to hemodynamic variables and tissues blood flow; however, higher levels may induce a decrease in cardiac output and tissue blood flow.

Oxyntic lesions may be provoked in the rat both by the process of acid secretion and also by gastric acidity

BACKGROUND

Gastric ischaemia appears to be a common pathogenetic factor for stress ulcers. These ulcers occur predominantly in the oxyntic mucosa, suggesting that the acid secretory process or its stimulation is involved in the pathogenesis.

METHODS

We examined separately the role of the acid secretory process and gastric luminal acidity in the pathogenesis of gastric lesions using the isolated vascularly perfused acid-secreting rat stomach.

RESULTS

Pentagastrin-stimulated acid secretion induced submucosal bleeding in the oxyntic mucosa whether accompanied by perfusion of the gastric lumen with saline or a phosphate buffer at pH 7.0. On the other hand, acidity, whether endogenous or introduced by luminal perfusion, induced erosions in both the oxyntic and antral mucosa.

CONCLUSION

It is concluded that the acid secretory process itself contributes to the particular vulnerability of the oxyntic mucosa to ischaemia. Histamine released upon stimulation of gastric acid secretion or shortage of energy due to the requirements for acid secretion may both contribute to this vulnerability. Furthermore, these findings suggest that inhibition of gastric acid secretion should be superior to antacids in preventing stress ulcers.

Acute erosions of the gastric mucosa in burned rats: effect of sucralfate

The effect of intragastric sucralfate on development of gastric erosions in burns was studied in 20 rats anaesthetised with midazolam/fentanyl/fluanisone. Gastric blood flow was measured by radioactive microspheres immediately before, and 20, 40, and 120 minutes after the rats had been burned. Significantly fewer erosions were found in the 10 rats treated with sucralfate (less than 2% of the gastric mucosal surface was affected) compared with the controls (16% of the mucosa affected). There was no difference in the rate of gastric blood flow in any part of the stomach between the rats treated with sucralfate and the controls. We conclude that sucralfate is effective in preventing gastric erosions in burned rats, but that other mechanisms of action than increase gastric blood flow are responsible for its protective effect.

Role of sensory afferent neurons in hypertonic damage and restitution of the rat gastric mucosa

BACKGROUND & AIMS

Gastric mucosal hyperemia is a protective response mediated at least in part by the response of sensory afferent neurons to hydrogen ions. The aim of this study was to determine if other pathways to the hyperemic response are present and if these neurons have an effect exclusive of hyperemia on mucosal protection and repair.

METHODS

Rat sensory afferent neurons were ablated by capsaicin treatment. Chambered stomachs were damaged by hypertonic saline followed by either acidic or neutral isotonic saline. Blood flow was measured by laser Doppler velocimetry, and mucosal morphology was quantitatively evaluated by microscopy.

RESULTS

Mucosal damage alone evoked a strong hyperemic response in both control and ablated rats. Ablated rats lost gastric protection despite this hyperemic response. Acid exposure after damage sustained the hyperemic response. Rapid epithelial restitution occurred faster (even over hemorrhagic lesions) in control rats.

CONCLUSIONS

The hyperemic response to mucosal damage alone is not mediated by sensory neurons. Protection of the stomach by sensory afferent neurons occurs by mechanisms also unrelated to their elicitation of hyperemia. Restitution during acid challenge is enhanced by the sustained hyperemic response mediated through sensory afferent neurons.

Role of gastric blood flow in impaired defense and repair of aged rat stomachs

To study impaired gastric mucosal tolerance against noxious agents in aged rats, possible factors underlying this observation were compared in anesthetized Fisher 344 young and aged rats. The gastric mucosa was damaged by in situ exposure to 80% ethanol for 30-45 s and by 1 M NaCl for 10 min followed by saline (pH = 1.0) for 60 min in chambered stomachs. The lesion area was significantly larger and epithelial restitution was significantly slower in aged than in young rats after both types of injury. Changes in gastric blood flow were monitored by laser-Doppler velocimetry. Young, but not aged, rats showed a marked increase in gastric blood flow in response to 1 M NaCl, acid challenge, and 640 microM capsaicin for 60 min. Young rats showed a higher density of calcitonin gene-related peptide (CGRP)-staining nerve fibers around submucosal blood vessels and higher mucosal release of prostaglandin E2 and leukotriene C4 than did aged rats. These data suggest that impaired mucosal defense and reduced restitution in aged rats is related to lack of hyperemic response caused by mucosal injury and H+ back-diffusion, which is probably due to decreased density of CGRP-staining nerve fibers and prostaglandin biosynthetic capacity in the mucosa.

Morbidity, ability to swallow, and survival, after oesophagectomy for cancer of the oesophagus and cardia

OBJECTIVE

To study survival, morbidity, and ability to swallow, after oesophagectomy for cancer of the oesophagus and cardia.

DESIGN

Prospective open study.

SETTING

University hospital, Norway.

SUBJECTS

83 patients, 38 with squamous cell carcinoma and 45 with adenocarcinoma of the oesophagus and cardia.

INTERVENTIONS

Transhiatal (n = 51) and transthoracic (n = 32) oesophagectomy. Oesophageal replacement was by either stomach (n = 80) or colon (n = 3). Cervical anastomosis was used in all but 2.

MAIN OUTCOME MEASURES

Early and late morbidity and mortality, length of stay in intensive care unit and in hospital, and survival analysis.

RESULTS

30 Day and in hospital mortality were 0 and 4% for transhiatal, and 6% and 9% for transthoracic, oesophagectomy. Complications included recurrent nerve palsy (n = 7), anastomotic leaks (n = 5), and chylothorax (n = 4). 17 Patients (22%) needed dilatations for stenosis of the anastomosis, and 71 (85%) of the patients left hospital within four weeks of operation. Survival analysis showed a 5 year survival rate of 33% for patients with adenocarcinoma operated on for cure and a 2 year survival of 28% for patients with squamous cell carcinoma.

CONCLUSIONS

Oesophagectomy for cure is worthwhile as some patients are cured and most of the remainder have prolonged relief of their dysphagia. Palliative resections should not be done in patients with distant metastases or invasion of adjacent organs by the tumour because of long stay in hospital, appreciable morbidity, and short life expectancy.

Burst abdomen and incisional hernia after major gastrointestinal operations--comparison of three closure techniques

OBJECTIVE

To compare the incidence of burst abdomen and incisional hernia after three different techniques of closure of the abdominal wall after major gastrointestinal operations.

DESIGN

Prospective, randomised, controlled trial.

SETTING

University hospital, Norway.

SUBJECTS

599 adults who underwent major operations for gastrointestinal conditions between December 1990 and February 1992.

INTERVENTIONS

Patients were randomised in three groups for abdominal wall closure by continuous mass polyglyconate (Maxon) double suture with loop, continuous mass polyglactin 910 (Vicryl), and interrupted polyglactin 910 (Vicryl) (layered for transverse and mass for midline incisions).

MAIN OUTCOME MEASURES

Burst abdomen during the postoperative period, and incisional hernia after one year follow up.

RESULTS

The incidence of wound dehiscence was 2% and of incisional hernia at one year 7%. There were no differences in the rate of dehiscence among the groups, but there were significantly more hernias in the polyglyconate group (19/164, 12%) compared with the two in which polyglactin 910 was used (16/327, 5%). Wound infections developed in 84/583 of our patients (14%) and the incidence was closely associated with emergency operations and contamination. Wound complications were not associated with the closure technique.

CONCLUSIONS

Wound infection is the most important single factor in the development of burst abdomen and incisional hernia. The continuous closure technique is quicker, cheaper, and as safe as the interrupted technique.

Gastric mucosal repair and release of HCO3- after damage by 2 M NaCl in cat: role of systemic acid base status

To study the influence of acid base balance on gastric mucosal repair, NH4Cl or NaHCO3 was given intravenously to anesthetized cats after mucosal damage induced by intraluminal 2 M NaCl. Saline at pH 5 or 1 was perfused via an oral tube through the stomach lumen and evacuated via a pyloric tube to a chamber with pH and PCO2 electrodes. Luminal bicarbonate (HCO3-) was markedly increased early after damage in both acidotic and alkalotic animals. In alkalotic animals mucosal blood flow increased about twofold in response to mucosal damage, whereas the early hyperemic response was either completely attenuated or blunted in acidotic animals. HCO3- release was correlated to availability of HCO3- by blood in alkalotic animals with luminal pH 5. Alkalotic animals showed improved repair compared with acidotic animals, and mucosal restitution was correlated to availability of HCO3- by blood. We conclude that luminal leakage of HCO3- or plasma after mucosal damage depends on availability by blood and consumption of HCO3- within the mucosa and that blood borne HCO3- has a major influence on gastric mucosal repair.

Role of bicarbonate in blood flow-mediated protection and repair of damaged gastric mucosa in the cat

BACKGROUND/AIMS

The hyperemic response after superficial gastric mucosal damage is essential for repair of the mucosa. Only indirect evidence suggests that this is caused by supply of bicarbonate. Therefore, this study tested the effect of maintaining the availability of bicarbonate after prevention of the hyperemic response after damage by 2 mol/L NaCl.

METHODS

Celiac artery flow was reduced, as monitored by Doppler ultrasonography, by gradual constriction of the vessel after mucosal damage. Saline (pH 1.0) was perfused through the stomach lumen and thereafter through a closed chamber with pH and PCO2 electrodes.

RESULTS

Exposure to 2 mol/L NaCl produced a marked increase of mucosal blood flow as measured by microspheres (P < 0.025) and a high degree of mucosal restitution 90 minutes after damage as judged by microscopy, whereas prevention of the hyperemic response caused extensive erosions and much less restitution (P < 0.001). The latter effect was completely counteracted by intravenous bicarbonate. High blood concentration of bicarbonate increased luminal release of bicarbonate, whereas high mucosal blood flow did not.

CONCLUSIONS

These data show that bicarbonate is an important factor in blood flow-mediated protection and repair of damaged gastric mucosa and suggest that concentration gradients are the major determinants for transport of bicarbonate across the damaged and restituted mucosa.

Release of bicarbonate from damaged and restituted gastric mucosa in the cat

BACKGROUND

Gastric mucosal damage leads to luminal alkalinization, but its dependence on mucosal blood flow and acid secretory state of the mucosa is not known. This study examined release of bicarbonate to the gastric lumen and mucosal blood flow in cats after mucosal damage caused by 2 mol/L NaCl and during 90 minutes of epithelial restitution.

METHODS

Bicarbonate was calculated from measurements of pH and PCO2 in the luminal perfusate. Mucosal blood flow was measured with microspheres.

RESULTS

Luminal bicarbonate increased more than twofold after damage in pharmacologically nontreated, pentagastrin-treated, and omeprazole-treated animals (P < 0.001). Luminal bicarbonate thereafter decreased completely to pre-damage level in pentagastrin-treated, partly in nontreated, but remained elevated in omeprazole-treated animals. Mucosal blood flow increased about 100% 15 minutes after damage (P < 0.001), irrespective of secretory state. Bicarbonate availability (arterial [HCO(3-)] x mucosal blood flow) was significantly related to luminal release of bicarbonate from the newly damaged (P < 0.01) but not from the restituted mucosa.

CONCLUSIONS

(1) From the newly damaged mucosa, the luminal release of bicarbonate is related to availability of blood-borne bicarbonate. (2) From acid-stimulated restituted mucosa, the bicarbonate produced by the parietal cells is not released to the lumen, but either consumed within the mucosa by back-diffusing H+ or distributed to the systemic circulation.

Adaptive protection related to clearance of ethanol in gastric mucosa of cats

This study was designed to test the hypothesis that hyperemia after exposure to 2 M NaCl protects the gastric mucosa against damage caused by absolute ethanol by removing ethanol diffusing from the gastric lumen into the mucosa. The stomach of anesthetized cats was perfused with saline at pH 1.0. Gastric mucosal blood flow was determined by radioactive microspheres, and portal vein blood flow was measured by Doppler ultrasound flowmetry. The concentration of ethanol in the corpus mucosa and the amount of ethanol transported away from the stomach in portal blood were measured by using absolute ethanol containing trace amounts of 14C-labeled ethanol. Pretreatment with 2 M NaCl for 10 min increased mucosal blood flow and prevented the development of deep mucosal lesions after subsequent application of absolute ethanol. An inverse correlation was found between mucosal blood flow and the degree of ethanol-induced damage. The mucosal content of ethanol was low in animals pretreated with hyperosmolar NaCl, and the degree of mucosal damage was related to the tissue concentration of ethanol. The amount of ethanol transported by blood from the stomach increased with increasing mucosal blood flow. We conclude that the mild irritant, 2 M NaCl, increases mucosal blood flow, which protects the mucosa by removing ethanol diffusing from the lumen. Thus, the mucosal ethanol concentration remains below a level that causes damage.

Role of blood flow in adaptive protection of the cat gastric mucosa

This study was designed to test the hypothesis that adaptive cytoprotection is related to increased blood flow caused by mild irritants. The stomach of cats was perfused with saline at pH 1.0. Mucosal blood flow was determined by radioactive microspheres, and celiac artery blood flow was measured by Doppler ultrasound. Gastric blood flow was left undisturbed or reduced by tightening a vessel loop around the celiac artery. Mucosal exposure to absolute ethanol for 2 minutes caused extensive damage to the surface epithelium, the pits, and the upper half of the glands. Pretreatment of the mucosa with 2 mol/L NaCl for 10 minutes prevented the development of mucosal lesions after subsequent application of absolute ethanol. The mucosal blood flow increased markedly after treatment with 2 mol/L NaCl. When this hyperemic response was inhibited by reducing celiac artery blood flow, ethanol caused lesions of similar degree as in animals not pretreated with 2 mol/L NaCl. A highly significant correlation was obtained between mucosal blood flow, as determined just before the application of ethanol, and the degree of ethanol-induced damage. At a chosen level of blood flow, ethanol caused the same degree of damage with or without pretreatment with 2 mol/L NaCl. In conclusion, high mucosal blood flow caused by a mild irritant is an important factor in adaptive gastric protection. With the present experimental setup, the protection could be fully explained as a result of the hyperemic response caused by 2 mol/L NaCl.

Pancreatic ascites: treatment by continuous somatostatin infusion

Two male patients with recurrent acute pancreatitis due to alcohol abuse were admitted with pancreatic ascites (high concentration of amylase, raised protein concentration, no specific cytologic features). Ultrasound (US) and computed tomography (CT) confirmed gross ascites and inflammation of the pancreas in both patients, and a pseudocyst in the head of the pancreas in one of them. Treatment with total parenteral nutrition (TPN) and a H2-blocking agent was instituted and continued for 4 and 2 wk, respectively. Due to lack of improvement, somatostatin infusion (250 micrograms/h) was started. During the next few days, there was a rapid improvement of the clinical status, and the production of ascites ceased. We conclude that somatostatin infusion should be tried before any invasive diagnostic or therapeutic intervention in patients with pancreatic ascites.

Gastric bicarbonate secretion, acid secretion, and mucosal blood flow during influence of pentagastrin and omeprazole in the cat

In this study secretion of bicarbonate and acid and mucosal blood flow were determined simultaneously in cats. The gastric lumen of anesthetized cats was continuously perfused with isotonic saline. Secretion of HCO-3 and H+ was calculated from continuous measurements of pH and PCO2 in the perfusate. Mucosal blood was measured by means of radiolabeled microspheres. Under resting acid secretory conditions, bicarbonate secretion into the gastric lumen averaged 1.0 mumol/min. Somewhat surprising, both omeprazole (4 mg/kg as bolus) and pentagastrin (16 micrograms/kg.h intravenously) significantly reduced the HCO-3 secretion. Omeprazole did not influence mucosal blood flow, whereas corpus mucosal blood flow increased during pentagastrin stimulation. Under resting acid secretory conditions and during omeprazole treatment there was a close linear relationship between acid and bicarbonate secretion. No such relationship was found during pentagastrin stimulation of the mucosa. No consistent relationship was obtained between blood flow and bicarbonate secretion in normal gastric mucosa.

[Crohn disease. Diagnosis and treatment]

Crohn's disease was the topic of a meeting of gastroenterologists in Bergen last year with the purpose of working out consensus guidelines for diagnosis and treatment of this chronic disease. The most important diagnostic procedures are radiology, gastrointestinal endoscopy and histopathology. Transmural, segmental involvement is characteristic, whereas granulomas are found in only 25% of biopsy specimens. Corticosteroids are effective in active Crohn's disease located to all parts of the intestine, whereas sulfasalazine and metronidazole are most effective in Crohn's colitis. Azathioprine and 6-mercaptopurine should be reserved for patients with chronic active disease that is unresponsive to steroids or requires higher doses. Azathioprine also has a prophylactic effect. Surgery is indicated in patients whose quality of life is diminished in spite of adequate medical treatment, in patients with bowel or ureter stenosis, fistula or abscess, and in patients with acute perforation or toxic dilatation. Limited resection is recommended, and stricture plasty can be alternative to extensive resection.

Acute erosions of the gastric mucosa in burned rats: effect of gastric acidity and fluid replacement

Early changes in the morphology of the gastric mucosa after the skin had been burned were studied using a standardised model in rats. A full thickness burn was inflicted by exposing about 20% of the total body surface area to hot water (99 degrees C) for 10 s. Intragastric acidity was kept at pH 1.0 or pH 7.4 in six experimental groups of eight rats. Rats were subjected to burns with the stomach irrigated at pH 1.0 or pH 7.4. Parallel groups received fluid replacement with a solution of human albumin, and two uninjured groups served as controls. Lesions of the gastric mucosa were measured by planimetry of photographs, and light microscopy was used for histological examination. At an intragastric pH of 1.0, the burned rats developed mucosal erosions covering an average of 13% of the total glandular mucosa; the remaining groups had only minimal mucosal lesions. Erosions of the gastric mucosa after the skin had been burned could be prevented in two ways--either by establishing an alkaline (pH 7.4) milieu in the gastric lumen, or by replacing sufficient fluid to maintain aortic blood pressure at the pre-experiment level. Fluid replacement prevented mucosal erosions even if the intragastric pH was kept at 1.0. Thus both luminal acidity and local tissue blood flow are possible mechanisms for gastric epithelial damage following burns of the skin.

[Reflux esophagitis. Diagnosis and treatment]

Refluxoesophagitis was the topic of a meeting of gastroenterologists in Bergen this year for the purpose of working out consensus guidelines on the diagnosis and treatment of this common disease. To day upper gastrointestinal endoscopy is the most important diagnostic procedure. There was a general agreement on using Berstad's staging scheme, which comprises only three stages of oesophagitis. Twenty-four hour pH-monitoring may provide useful information on the reflux pattern, but the practical consequences of the examination are still uncertain. H2-receptor antagonists are indicated in mild cases of oesophagitis. However, omeprazol is the only drug having a significant effect on endoscopic healing and therefore the drug of choice in severe oesophagitis. At present, there is no established maintenance treatment. Surgery is therefore recommended in patients with severe oesophagitis which does not respond to medical treatment, in patients with strictures, and in patients with severe Barrett's oesophagus. The Nissen-Rosetti fundoplicatio is recommended as the standard operative procedure.

Regional blood flow and acid secretion associated with damage and restitution of the gastric surface epithelium in cats

The gastric mucosa of anesthetized cats was exposed to 2 M NaCl for 10 min. After returning to gastric perfusion with 150 mM NaCl and pH 7.40, with and without pentagastrin stimulation, transmucosal potential difference decreased to zero and then gradually increased to approximately half the original value during the following 90 min. H+ secretion decreased and remained close to zero after exposure to 2 M NaCl in nonstimulated cats, whereas pentagastrin-stimulated secretion gradually increased to nearly half the preexposure level. Mucosal blood flow increased, and the vascular resistance decreased in the posterior wall of the stomach corresponding to epithelial damage, as observed by light microscopy after 15 min. Blood flow during pentagastrin stimulation was initially high in fundus and corpus and did not increase further after exposure to 2 M NaCl, but showed similar changes as without pentagastrin in the antrum. Epithelial restitution occurred within 90 min during both nonstimulated conditions and pentagastrin stimulation. In control animals subjected to 150 mM NaCl there were no changes in transmucosal potential difference, H+ secretion, or blood flow throughout the experiment and epithelial damage was not found. In conclusion, damage caused by 2 M NaCl to the gastric surface epithelium was associated with decreased acid secretion and increased mucosal blood flow. These factors may contribute to creating favorable conditions for the epithelial restitution, indicated by restoration of transmucosal potential difference and observed by light microscopy.