Increased oxidative stress with substantial dysregulation of genes related to oxidative stress and DNA repair after laparoscopic colon cancer surgery

The dose-response relationships of the direct scavenging activity of amide-based local anesthetics against multiple free radicals

This study aimed to illustrate the dose-response relationships of the direct scavenging activity of amide-based local anesthetics against multiple free radicals in vitro. We have demonstrated that amide-type local anesthetics selectively and directly scavenge some free radicals. Three kinds of free radicals were eliminated by all the four local anesthetics examined. Mepivacaine, lidocaine, bupivacaine, and dibucaine scavenged hydroxyl radicals in dose-dependent manners. Ascorbyl free radicals were also scavenged in dose-dependent manners, and lastly singlet oxygen was scavenged in dose-dependent manners. Three other free radicals were not scavenged by all of the four local anesthetics; tert-butoxyl radical was scavenged by all the anesthetics examined but dibucaine, nitric oxide by mepivacaine but not by the other three, and tyrosyl radical by mepivacaine and lidocaine but not by the other two. Some free radicals (superoxide anion, tert-butyl peroxyl radical, DPPH) were not scavenged by any of the four local anesthetics. The local anesthetics were also shown to inhibit lipid peroxidation by TBARS assay. These results suggest that local anesthetics have antioxidant properties through their free radical scavenging activities.

Riskscore Model Based on Oxidative Stress-Related Genes May Facilitate the Prognosis Evaluation for Patients With Colon Cancer

INTRODUCTION

This study aims to identify the oxidative stress-related genes (OSRGs) with prognostic value and develop a riskscore model for prognosis evaluation in colon cancer.

METHODS

The transcriptome data and corresponding clinical information about colon cancer were extracted from The Cancer Genome Atlas database. Differentially expressed OSRGs and transcription factors (TFs) were identified between the normal and tumor samples. A riskscore model was established with OSRGs filtered from Cox regression analysis. This riskscore model was appraised by Kaplan-Meier plot, receiver operating characteristic curve, and Cox regression analysis. The clinical relevance of riskscore and its association with immune cell infiltration were also evaluated.

RESULTS

A total of 307 differentially expressed OSRGs and 64 differential TFs were identified. A TF-OSRG regulatory network was constructed in Cytoscape software. A riskscore model was established based on 17 OSRGs with independent prognostic value. This riskscore model could separate the patients into low-risk and high-risk groups. It also had good predictive ability, with an area under the curve = 0.8. In multivariate Cox regression analysis, age, T stage, and riskscore were identified as independent risk factors in colon cancer. Riskscore was significantly correlated with T stage, N stage, and immune cell infiltration.

DISCUSSION

We established a useful riskscore model with 17 OSRGs for prognosticating the overall survival in patients with colon cancer. This study provides a new insight into the clinical utility of OSRG-based riskscore model, which will hopefully facilitate the prognosis evaluation of patients with colon cancer.

Effect of remote ischemic preconditioning on postoperative gastrointestinal function in patients undergoing laparoscopic colorectal cancer resection

PURPOSE

Patients undergoing laparoscopic colorectal cancer resection have a high incidence of postoperative gastrointestinal dysfunction (POGD). Remote ischemic preconditioning (RIPC) is an organ protection measure. The study investigated the effect of RIPC on postoperative gastrointestinal function.

METHODS

In this single-center, prospective, double-blinded, randomized, parallel-controlled trial, 100 patients undergoing elective laparoscopic colorectal cancer resection were randomly assigned in a 1:1 ratio to receive RIPC or sham RIPC (control). Three cycles of 5-min ischemia/5-min reperfusion induced by a blood pressure cuff placed on the right upper arm served as RIPC stimulus. Patients were followed up continuously for 7 days after surgery. The I-FEED score was used to evaluate the patient's gastrointestinal function after the surgery. The primary outcome of the study was the I-FEED score on POD3. Secondary outcomes include the daily I-FEED scores, the highest I-FEED score, the incidence of POGD, the changes in I-FABP and the inflammatory markers (IL-6 and TNF-α), and the time to first postoperative flatus.

RESULTS

A total of 100 patients were enrolled in the study, of which 13 patients were excluded. Finally, 87 patients were included in the analysis, 44 patients in the RIPC group and 43 patients in the sham-RIPC group. Patients assigned to the RIPC group had a lower I-FEED score on POD3 compared with the sham-RIPC group (mean difference 0.86; 95% CI: 0.06 to 1.65; P = 0.035). And patients in the RIPC group were also associated with a lower I-FEED score on POD4 vs the sham-RIPC group (mean difference 0.81; 95% CI: 0.03 to 1.60; P = 0.043). Compared with the sham-RIPC group, the incidence of POGD within 7 days after surgery was lower in the RIPC group (P = 0.040). At T₁, T₂, and T₃ time points, inflammatory factors and I-FABP were considerably less in the RIPC group compared to the sham-RIPC group. The time to the first flatus and the first feces was similar in both groups.

CONCLUSION

RIPC reduced I-FEED scores, decreased the incidence of postoperative gastrointestinal dysfunction, and lowered concentrations of I-FABP and inflammatory factors.

Alterations in blood microbiota after colonic cancer surgery

BACKGROUND

Mechanisms contributing to the perioperative stress response remain poorly understood. This study investigated changes in the amount of bacterial DNA in blood and the diversity of blood microbiota in the perioperative period in patients undergoing minimally invasive surgery for colonic cancer in an enhanced recovery after surgery setting.

METHODS

DNA encoding the bacterial 16S ribosomal RNA gene (16S rDNA) in whole blood obtained the day before surgery, and on postoperative day (POD) 1 and POD 10-14 was amplified and quantified by PCR before sequencing for taxonomic assignment. Richness, evenness and similarity measures were calculated to compare microbiota between days. Differences in relative abundance were analysed using the linear discriminant analysis effect size (LEfSe) algorithm.

RESULTS

Thirty patients were included between January and July 2016. The concentration of bacterial 16S rDNA in blood increased between the day before surgery and POD 1 (P = 0.025). Bacterial richness was lower on POD 10-14 than on the day before surgery and POD 1 (both P < 0·001). LEfSe analysis comparing the day before surgery and POD 10-14 identified changes in the abundance of several bacteria, including Fusobacterium nucleatum, which was relatively enriched on POD 10-14.

CONCLUSION

These findings suggest that the blood of patients with colonic cancer harbours bacterial 16S rDNA, which increases in concentration after surgery.