Navigation-Assisted Surgery for Locally Advanced Primary and Recurrent Rectal Cancer.

BACKGROUND: In some surgical disciplines, navigation-assisted surgery has become standard of care, but in rectal cancer, indications for navigation and the utility of different technologies remain undetermined. METHODS: The NAVI-LARRC prospective study (NCT04512937; IDEAL Stage 2a) evaluated feasibility of navigation in patients with locally advanced primary (LARC) and recurrent rectal cancer (LRRC). Included patients had advanced tumours with high risk of incomplete (R1/R2) resection, and navigation was considered likely to improve the probability of complete resection (R0). Tumours were classified according to pelvic compartmental involvement, as suggested by the Royal Marsden group. The BrainlabTM navigation platform was used for preoperative segmentation of tumour and pelvic anatomy, and for intraoperative navigation with optical tracking. R0 resection rates, surgeons' experiences, and adherence to the preoperative resection plan were assessed. RESULTS: Seventeen patients with tumours involving the posterior/lateral compartments underwent navigation-assisted procedures. Fifteen patients required abdominosacral resection, and 3 had resection of the sciatic nerve. R0 resection was obtained in 6/8 (75%) LARC and 6/9 (69%) LRRC cases. Preoperative segmentation was time-consuming (median 3.5 h), but intraoperative navigation was accurate. Surgeons reported navigation to be feasible, and adherence to the resection plan was satisfactory. CONCLUSIONS: Navigation-assisted surgery using optical tracking was feasible. The preoperative planning was time-consuming, but intraoperative navigation was accurate and resulted in acceptable R0 resection rates. Selected patients are likely to benefit from navigation-assisted surgery.

Higher TNFα responses in young males compared to females are associated with attenuation of monocyte adenylyl cyclase expression.

Tumor necrosis factor α (TNFα) expression is strongly attenuated by the intracellular signaling mediator cyclic adenosine monophosphate (cAMP), which is synthesized by adenylyl cyclase (AC) enzymes. We have compared AC regulation and TNFα production in male and female monocytes, and characterized the role of monocyte AC isoforms in TNFα regulation. Males and females, age groups 20-30 years and 50-70 years donated blood for this study. In lipopolysaccharide-stimulated blood from young male donors, we observed significantly higher TNFα responses (6h, p=0.03) compared to females of the same age, a difference not observed in the older donors. Rapid down-regulation of the monocyte AC isoforms AC4, AC7 and AC9 were observed in young males. AC-directed siRNA experiments in the human monocyte cell line THP-1 demonstrated that AC7 and AC9 knock-down significantly induced TNFα release (p=0.01 for both isoforms). These data indicate that the stronger TNFα-responses in young males may be partly associated with male-specific down-regulation of adenylyl cyclases.

Human monocyte responses to lipopolysaccharide and 9-cis retinoic acid after laparoscopic surgery for colon cancer.

Surgery, even modern minimal invasive laparoscopic surgery, induces an initial inflammatory and acute phase response which is followed by a period of immunosuppression rendering surgical patients more susceptible to infection. Here, we aimed to study changes in monocyte inflammatory responses and inflammatory modulation mechanisms following laparoscopic colorectal surgery for colon cancer. Blood samples were collected from 19 colon cancer patients before, directly after and daily for 3 days following surgery. Blood cells were exposed ex vivo to bacterial lipopolysaccharide (LPS) or the inflammatory modulator 9-cis retinoic acid (9cisRA). In blood samples taken prior to surgery, we found significant pro-inflammatory responses to LPS, indicating classical monocyte activation. Directly after surgery, LPS induced significantly less early pro-inflammatory cytokines and monocyte/granulocyte-attracting chemokines. The LPS-mediated release of interleukin (IL)-1ß was still significantly attenuated 3 days after surgery. In patient monocytes collected after surgery, we found increased levels of suppressors of cytokine signaling (SOCS)1 and SOCS3 mRNA, reported to be associated with polarization towards resolving macrophages. The retinoic acid isomer 9cisRA, reported to attenuate LPS-mediated inflammatory responses and alter chemokine responses in cultured monocytes, had a similar effect in patient blood. Three days after surgery, 9cisRA still attenuated pro-inflammatory responses, but the induction of monocyte chemoattractive protein (MCP)-1/CCL2 mRNA in monocytes was reduced. This study indicates changes in monocyte responses that last for at least 3 days after laparoscopic surgery.

9-cis retinoic acid inhibits inflammatory responses of adherent monocytes and increases their ability to induce classical monocyte migration.

Patients with vitamin A/retinol deficiency are shown to be prone to infections and to suffer from increased inflammation, effects which can be remedied by vitamin A supplements. We aimed to study how human monocytes from the peripheral venous blood of healthy donors acted within the initial hours after adherence and exposure to bacterial endotoxin in the presence or absence of the 9-cis-isomer of retinoic acid (9cisRA). We found that adherent human monocytes were dominated by the CD14dimCD16+ subtype. Pretreatment with 9cisRA for 1 h significantly decreased lipopolysaccharide (LPS)-induced mRNA expression and protein release of tumor necrosis factor (TNF)α, interleukin (IL)-6 and chemokine ligands (CCL)3 and CCL4. In contrast, treatment with 9cisRA rapidly enhanced the production of monocyte chemoattractive protein/CCL2. 9cisRA treatment also led to enhanced migration of classical CD14high monocytes in a transwell in vitro system. We conclude that 9cisRA treatment of human adherent monocytes attenuates the inflammatory responses to LPS and induces the attraction of classical monocytes, a feature which may help explain why supplements administered to vitamin A-deficient patients counteract inflammation and increases the ability to fight infections.

Liver X receptor is a key regulator of cytokine release in human monocytes.

Aberrant regulation of innate immune responses and uncontrolled cytokine bursts are hallmarks of sepsis and endotoxemia. Activation of the nuclear liver X receptor (LXR) was recently demonstrated to suppress inflammatory genes. Our aim was to investigate the expression of LXR in human monocytes under normal and endotoxemic conditions and to study the influence of LXR activation on endotoxin-induced cytokine synthesis and release. Adherent human monocytes or whole blood were pretreated with a synthetic LXR agonist (3-{3-[(2-chloro-3-trifluoromethyl-benzyl)-(2,2-diphenyl-ethyl)-amino]-propoxy}-phenyl)-acetic acid) and subsequently challenged with LPS (from Escherichia coli) or peptidoglycan (from Staphylococcus aureus). Cytokine release was assessed by a Multiplex antibody bead kit, and cytokine mRNA levels were measured by real-time reverse-transcriptase-polymerase chain reaction. We found that LXRalpha mRNA was up-regulated in CD14+ monocytes in LPS-challenged blood, whereas LXRbeta mRNA was not altered. Addition of 3-{3-[(2-chloro-3-trifluoromethyl-benzyl)-(2,2-diphenyl-ethyl)-amino]-propoxy}-phenyl)-acetic acid to monocytes suppressed the LPS-induced release of IL-1beta, IL-6, IL-8, IL-10, IL-12p40, TMF-alpha, macrophage inflammatory protein 1alpha, macrophage inflammatory protein 1beta, and monocyte chemoattractant protein 1 in a concentration-dependent manner. Surprisingly, an accompanying decrease in cytokine mRNA accumulation was not observed. The suppressed cytokine release could not be explained by a diminished transport of mRNA out of the nucleus or a decreased secretion of cytokines. We propose that LXR is a key regulator of cytokine release in LPS-challenged human monocytes, possibly by interfering with translational events.

Activation of the liver X receptor protects against hepatic injury in endotoxemia by suppressing Kupffer cell activation.

Recent reports have demonstrated that liver X receptors (LXRs) of the nuclear receptor family have anti-inflammatory effects on macrophages. Here we examine whether activation of LXR by the synthetic agonist GW3965 can ameliorate the liver injury/dysfunction caused by endotoxins in the rat. Male Wistar rats received GW3965 (0.3 mg/kg) or vehicle (50% dimethyl sulfoxide) 30 min before coadministration of lipopolysaccharide (LPS, 5 mg/kg i.v.) and peptidoglycan (1 mg/kg i.v.). Treatment with GW3965 attenuated the increase in the plasma levels of alanine aminotransferase and bilirubin (markers of liver injury/dysfunction) as well as the focal hepatocyte necrosis (histology) caused by coadministration of LPS and peptidoglycan. This protective effect of GW3965 treatment was associated with reduced infiltration of mast cells in the liver (histopathology) and reduced gene expression of the chemokines eotaxins 1 and 2, whereas MIP-2 mRNA levels were not affected. Plasma levels of tumor necrosis factor alpha and prostaglandin E2 were significantly attenuated by GW3965, whereas plasma interleukins 6 and 10 were not altered. High expression of LXRalpha mRNA was observed in Kupffer cell cultures, suggesting that Kupffer cells are targets of GW3965. Subsequent in vitro studies in Kupffer cells demonstrated that exposure to GW3965 attenuated the LPS-induced release of tumor necrosis factor alpha and prostaglandin E2 in a dose-dependent manner. In conclusion, this study demonstrates that activation of LXR by GW3965 protects against liver injury and dysfunction in a rat model of endotoxemia, in part by exerting an anti-inflammatory effect on Kupffer cells.