Macrophages mediate colon carcinoma cell adhesion in the rat liver after exposure to lipopolysaccharide

The surgical resection of primary colorectal cancer is associated with an enhanced risk of liver metastases. Moreover, bacterial translocation or anastomic leakage during resection has been shown to correlate with a poor long-term surgical outcome, suggesting that bacterial products may contributeto the formation of metastases. Driven by these premises, we investigated the role of the bacterial product lipopolysaccharide (LPS) in the generation of liver metastases. Intraperitoneal injection of LPS led to enhanced tumor-cell adhesion to the rat liver as early as 1.5 h post-administration. Furthermore, a rapid loss of the expression of the tight junction protein zonula occludens-1 (ZO-1) was observed, suggesting that LPS disrupts the integrity of the microvasculature. LPS addition to endothelial-macrophage co-cultures damaged endothelial monolayers and caused the formation of intercellular gaps, which was accompanied by increased tumor-cell adhesion. These results suggest that macrophages areinvolved in the endothelial damage resulting from exposure to LPS. Interestingly, the expression levels of of ZO-1 were not affected by LPS treatment in rats in which liver macrophages had been depletedas well as in rats that had been treated with a reactive oxygen species (ROS) scavenger. In both settings, decreased tumor-cell adhesion was observed. Taken together, our findings indicate that LPS induces ROS release by macrophages, resulting in the damage of the vascular lining of the liver and henceallowing increased tumorcell adherence. Thus, peri-operative treatments that prevent the activation of macrophages and-as a consequence- limit endothelial damage and tumor-cell adhesion may significantly improve the long-term outcome of cancer patients undergoing surgical tumor resection

Volume–outcome relationship of liver surgery: a nationwide analysis

Background: Evidence for an association between hospital volume and outcomes for liver surgery is abundant. The current Dutch guideline requires a minimum volume of 20 annual procedures per centre. The aim of this study was to investigate the association between hospital volume and postoperative outcomes using data from the nationwide Dutch Hepato Biliary Audit. Methods: This was a nationwide study in the Netherlands. All liver resections reported in the Dutch Hepato Biliary Audit between 2014 and 2017 were included. Annual centre volume was calculated and classified in categories of 20 procedures per year. Main outcomes were major morbidity (Clavien–Dindo grade IIIA or higher) and 30-day or in-hospital mortality. Results: A total of 5590 liver resections were done across 34 centres with a median annual centre volume of 35 (i.q.r. 20–69) procedures. Overall major morbidity and mortality rates were 11·2 and 2·0 per cent respectively. The mortality rate was 1·9 per cent after resection for colorectal liver metastases (CRLMs), 1·2 per cent for non-CRLMs, 0·4 per cent for benign tumours, 4·9 per cent for hepatocellular carcinoma and 10·3 per cent for biliary tumours. Higher-volume centres performed more major liver resections, and more resections for hepatocellular carcinoma and biliary cancer. There was no association between hospital volume and either major morbidity or mortality in multivariable analysis, after adjustment for known risk factors for adverse events. Conclusion: Hospital volume and postoperative outcomes were not associated

Evaluation of national surgical practice for lateral lymph nodes in rectal cancer in an untrained setting

Background. Involved lateral lymph nodes (LLNs) have been associated with increased local recurrence (LR) and ipsi-lateral LR (LLR) rates. However, consensus regarding the indication and type of surgical treatment for suspicious LLNs is lacking. This study evaluated the surgical treatment of LLNs in an untrained setting at a national level.Methods. Patients who underwent additional LLN surgery were selected from a national cross-sectional cohort study regarding patients undergoing rectal cancer surgery in 69 Dutch hospitals in 2016. LLN surgery consisted of either 'node-picking' (the removal of an individual LLN) or 'partial regional node dissection' (PRND; an incomplete resection of the LLN area). For all patients with primarily enlarged (=7 mm) LLNs, those undergoing rectal surgery with an additional LLN procedure were compared to those undergoing only rectal resection.Results. Out of 3057 patients, 64 underwent additional LLN surgery, with 4-year LR and LLR rates of 26% and 15%, respectively. Forty-eight patients (75%) had enlarged LLNs, with corresponding recurrence rates of 26% and 19%, respectively. Node-picking (n = 40) resulted in a 20% 4-year LLR, and a 14% LLR after PRND (n = 8; p = 0.677). Multivariable analysis of 158 patients with enlarged LLNs undergoing additional LLN surgery (n = 48) or rectal resection alone (n = 110) showed no significant association of LLN surgery with 4-year LR or LLR, but suggested higher recurrence risks after LLN surgery (LR: hazard ratio [HR] 1.5, 95% confidence interval [CI] 0.7-3.2, p = 0.264; LLR: HR 1.9, 95% CI 0.2-2.5, p = 0.874).Conclusion. Evaluation of Dutch practice in 2016 revealed that approximately one-third of patients with primarily enlarged LLNs underwent surgical treatment, mostly consisting of node-picking. Recurrence rates were not significantly affected by LLN surgery, but did suggest worse outcomes. Outcomes of LLN surgery after adequate training requires further research

Perioperative IFN-a to avoid surgically induced immune suppression in colorectal cancer patients

Surgical treatment of colorectal cancer is associated with postoperative immunosuppression, which might facilitate dissemination of tumor cells and outgrowth of minimal residual disease/(micro) metastases. Minimal residual disease has been shown to be of prognostic relevance in colorectal cancer. Therefore, stimulation of (anti-tumor) immune responses may be beneficial in the prevention of metastases formation. Important anti-tumor effector cells, which serve this function, are natural killer (NK) cells, CD8+ lymphocytes (CTL), dendritic cells (DC) and macrophages. In this review the immunomodulating properties of IFN-a are discussed, with a particular focus on perioperative stimulation of immune function in cancer patients. IFN-a is known to enhance innate immune functions such as stimulation of NK cells, transition from innate to adaptive responses (activation of DC) and regulating of CD8+ CTL activity and memory. Moreover, it exerts direct antitumor effects by regulating apoptosis and cell cycle. In several clinical trials, perioperative administration of IFN-a has indeed been shown to improve T cell responsiveness, prevent impairment of NK cell cytotoxicity and increase expression of activation markers on NK, T and NKT cells. In a clinical pilot study we showed in colorectal cancer patients that received perioperative IFN-a enhanced activation markers on T cells and NK cells, combined with betterpreserved T cell function as indicated by phytohemaggluttinin skin tests. In the liver of these patients significantly more CD8+ T cells were found. In conclusion, IFN-a provides an effective adjuvant in several forms of cancer and improves several postoperative immune functions in perioperative administration. However, larger clinical trials are necessary to investigate effects on disease-free and overall survival

Experimentally induced liver metastases from colorectal cancer can be prevented by mononuclear phagocyte-mediated monoclonal antibody therapy

Background 82 Aims: Development of liver metastases is a frequent complication in patients with colorectal cancer (CRC), even after successful resection of the primary tumor. As such, postoperative adjuvant therapies that aim to eliminate residual disease after surgery may improve patient outcome. Methods: We used a colon carcinoma liver metastases model, in which CC531s colon carcinoma cells are injected into the portal circulation by a surgical procedure. As injected tumor cells are arrested in the liver, this model is suitable for investigating the interaction of tumor cells with the liver microenvironment. By administering tumor specific monoclonal antibodies (mAb) directly post-operatively, we were able to determine the effect of antibody therapy on eradication of arrested tumor cells and subsequent liver metastases outgrowth. Results: We showed that post-operative treatment with tumor specific monoclonal antibodies (mAb) prevents liver metastases outgrowth. Antibody-dependent phagocytosis (ADPh) was the main mechanism involved, as enhanced uptake of tumor cells by innate mononuclear phagocytes in the liver was observed after mAb therapy. Furthermore, Kupffer cells (KC) were identified as the most prominent effector cells, as depletion of KC abolished therapeutic efficacy. This was partly compensated by monocytes when animals were treated with a high mAb dose, but monocytes were unable to phagocytose tumor cells when rats were treated with low mAb doses. Conclusions: The finding that KC and monocytes can eliminate tumor cells through ADPh has important and promising clinical implications for designing new adjuvant therapies for patients undergoing CRC resection. (C) 2010 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.Surgical oncolog

Tumor infiltrating macrophages reduce development of peritoneal colorectal carcinoma metastases

Macrophages generally constitute a major component of tumor stroma, and possess either tumor growth promoting or inhibiting capabilities. Classically activated macrophages exert cytotoxicity and produce inflammatory cytokines, which limits tumor growth. By contrast, alternatively activated or M2 macrophages induce tumor progression by stimulating angiogenesis and proliferation. Previously we showed that resident macrophages control metastatic spread of coloncarcinoma cells in liver and peritoneal tumor models. However, it is proposed that newly recruited macrophages develop into tumor-associated M2 macrophages, as they are exposed to a microenvironment that favors alternative activation. Previously we showed that monocyte migration was diminished after flavonoid treatment in an experimental autoimmune encephalomyelitis animal model. In the present study, we investigated the role of newly recruited macrophages in colon carcinoma development, by using the flavonoids rutin and luteolin to reduce monocyte migration into peritoneal tumors. Increased tumor development was observed in animals that were treated with rutin and luteolin. Immunohistochemical analyses showed that the number of ED2(+) resident macrophages was normal in tumors of animals that received rutin and luteolin treatment. However, the number of ED1(+) cells (marker immature macrophages) was reduced, indicating decreased macrophage recruitment. Thus, inhibition of monocyte migration promotes tumor growth, supporting that not only resident, but also newly recruited macrophages limit peritoneal colon carcinoma metastases developmen