Immunologic changes during minimally invasive surgery

Systemic inflammatory changes and their clinical implications following thoracic cancer surgery

Trauma that follows every surgical procedure triggers an inflammatory response, which in the majority of the cases reflects the associated tissue damage. Tissue regeneration, postoperative outcomes, and systemic antibacterial activity are highly dependent on the initial inflammatory response elicited by surgical trauma. More specifically, in thoracic surgery, systemic cytokine and cellular changes have an impact on several measured postoperative outcomes. Lastly, the introduction of video-assisted and robotic-assisted thoracic surgery has been shown to provide improved postoperative outcomes with altered systemic inflammatory response, when compared to open thoracic surgery. This review outlines the major systemic inflammatory changes observed in thoracic cancer surgery as well as its clinical significance.

Advances and challenges in laparoscopic surgery in the management of hepatocellular carcinoma

Hepatocellular carcinoma is the fifth most common malignancy and the third most common cause of cancer-related mortality worldwide. From the wide variety of treatment options, surgical resection and liver transplantation are the only therapeutic ones. However, due to shortage of liver grafts, surgical resection is the most common therapeutic modality implemented. Owing to rapid technological development, minimally invasive approaches have been incorporated in liver surgery. Liver laparoscopic resection has been evaluated in comparison to the open technique and has been shown to be superior because of the reported decrease in surgical incision length and trauma, blood loss, operating theatre time, postsurgical pain and complications, R0 resection, length of stay, time to recovery and oral intake. It has been reported that laparoscopic excision is a safe and feasible approach with near zero mortality and oncologic outcomes similar to open resection. Nevertheless, current indications include solid tumors in the periphery < 5 cm, especially in segments II through VI, while according to the consensus laparoscopic major hepatectomy should only be performed by surgeons with high expertise in laparoscopic and hepatobiliary surgery in tertiary centers. It is necessary for a surgeon to surpass the 60-cases learning curve observed in order to accomplish the desirable outcomes and preserve patient safety. In this review, our aim is to thoroughly describe the general principles and current status of laparoscopic liver resection for hepatocellular carcinoma, as well as future prospects.

Evidence for the absence of visceral pain in C57BL6/N mice subjected to therapeutically relevant O3/O2-pneumoperitoneum

Each different gas that is used to induce a pneumoperitoneum (PP) exhibits individual effects within the peritoneal cavity. This might include adverse effects such as pain and/or inflammatory reactions. The acute effects of ozonized oxygen (O₃/O₂), a highly oxidative gas mixture, after being insufflated into the peritoneal cavity are analysed in this study. Using the abdominal constriction response ('writhing') assay of chemical nociception in C57BL6/N mice, O₃/O₂-PP was found not to be associated with visible pain responses and did not alter the c-fos expression in the spinal cord. In addition, mRNA expression levels of the pro-inflammatory cytokines, interleukin (IL)-1β and IL-6, were found unaltered in the spleen 2 h after insufflation. In conclusion, O₃/O₂-PP is free of adverse pain and does not trigger inflammatory immune responses.

The Effect of Intraoperative N-Acetylcysteine on Hepatocellular Injury During Laparoscopic Bariatric Surgery. A Randomised Controlled Trial

BACKGROUND

The combination of pneumoperitoneum and intraoperative retraction of the left lobe of the liver leads to hepatocellular injury during laparoscopic gastric surgery. Fatty livers are more susceptible to ischaemic insults. This trial investigated whether the antioxidant N-acetylcysteine (NAC) reduced liver injury during laparoscopic sleeve gastrectomy (LSG).

METHODS

Patients undergoing LSG were randomised (single blinded) to receive intraoperative NAC infusion or standard anaesthetic treatment. Blood samples were taken before and after surgery (days 0 to 4). Primary endpoints included serum aminotransferases. Secondary measures were C-reactive protein, weight cell count (WCC), cytokines (interleukin 6 and 10) and cytokeratin-18 as markers of apoptosis. Intraoperative liver biopsy samples were assessed using a locally developed injury score.

RESULTS

Twenty patients (14 females, mean age 44.5 (SEM ± 2.9) years, mean BMI 60.8 (SEM ± 2.4) kg/m(2)) were recruited (NAC n = 10, control n = 10). The trial was stopped early after a planned interim analysis. Baseline liver function was similar. The peak rise in liver enzymes was on day 1, but levels were not significantly different between the groups. Rates of complications and length of stay were not significantly different. Secondary outcome measures, including white cell count (WCC), cytokines and cytokeratin (CK)-18 fragments, were not different between groups. Liver injury scores did not differ significantly.

CONCLUSIONS

NAC did not reduce intraoperative liver injury in this small number of patients. The heterogenous nature of the study population, with differences in co-morbidities, body mass index and intraabdominal anatomy, leads to a varied post-operative inflammatory response. Significant hepatocyte injury occurs through both necrosis and apoptosis.

Carbon dioxide‑pneumoperitoneum in rats reduces ischemia/reperfusion‑induced hepatic apoptosis and inflammatory responses by stimulating sensory neurons

Laparoscopic surgery induces a milder inflammatory response than open surgery, however, the precise mechanisms underlying this phenomenon remain to be elucidated. Our previous study demonstrated that stimulation of sensory neurons inhibited hepatic apoptosis and inflammatory responses in rats subjected to hepatic ischemia/reperfusion (I/R). Since carbon dioxide (CO2) has been demonstrated to stimulate sensory neurons, it was hypothesized that CO2‑pneumoperitoneum, as used in laparoscopic surgery, may attenuate inflammatory responses by stimulating sensory neurons. This hypothesis was examined using rats subjected to hepatic I/R. The rats were subjected to partial hepatic ischemia for 60 min followed by reperfusion. Abdominal insufflation with CO2 or air was performed for 30 min prior to hepatic I/R. Hepatic I/R‑induced hepatocellular apoptosis and expression of the neutrophil chemoattractant endothelial monocyte‑activated polypeptide‑II, were inhibited by CO2‑pneumoperitoneum, however, not by air‑pneumoperitoneum. Pretreatment with the transient receptor potential vanilloid 1 antagonist SB366791 reversed the protective effects of CO2‑pneumoperitoneum. The results from the present study demonstrated that CO2‑pneumoperitoneum attenuates hepatic apoptosis and inflammatory responses in rats subjected to hepatic I/R, possibly by stimulating sensory neurons. These findings suggested that CO2‑pneumoperitoneum contributed to the attenuated inflammatory response observed following laparoscopic surgery.

The humoral response after laparoscopic versus open colorectal surgery: a meta-analysis

BACKGROUND

The local and systemic humoral response after colorectal surgery is thought to affect postoperative recovery. It is commonly claimed that laparoscopic surgery elicits a diminished inflammatory response than equivalent open surgery. Despite these claims, the evidence is conflicting. Therefore, we aimed to systematically review the results from randomized controlled clinical trials comparing the humoral response associated with laparoscopic versus open colorectal surgery.

MATERIALS AND METHODS

A high-sensitivity search was conducted independently by two of the authors with no language restriction. Studies were identified from the Cochrane Central Register of Controlled Trials (CENTRAL/CCTR), Cochrane Library, Medline (January 1966 to January 2009), PubMed (1950 to January 2009), and Embase (1947 to January 2009). Relevant meeting abstracts and reference lists were manually searched. Data analysis was performed using Review Manager ver. 5.0.

RESULTS

Thirteen randomized controlled trials were included. Meta-analysis demonstrated a significantly higher serum IL-6 on d 1 after open colorectal resection for neoplasia (n = 97) compared with laparoscopic resection (n = 76, P = 0.0008) without significant heterogeneity. Data for plasma IL-6 were heterogeneous, with no apparent difference between groups. No other significant differences were identified, and there were not enough data on local peritoneal humoral factors to allow meta-analysis.

CONCLUSION

Open colorectal resection for neoplasia is associated with higher postoperative serum levels of IL-6 on d 1 than equivalent laparoscopic surgery. The aetiology and clinical significance of this finding is uncertain, and further studies are required to elucidate any differences in the local humoral response which may be more clinically relevant in surgery for this indication.

Microarray analysis of the differential effects of open and laparoscopic surgery on murine splenic T-cells

BACKGROUND

Surgical trauma depresses cell-mediated immunity of a duration and magnitude proportional to the degree of injury. However, the cellular mechanism underlying this effect is poorly understood. Microarrays were used to survey gene expression in murine splenic T-cells after pneumoperitoneum and laparotomy.

METHODS

C3H/HeJ mice were assigned randomly to undergo anesthesia alone, sham laparotomy, or CO(2) pneumoperitoneum and sacrificed 12 or 24 hours later. RNA was isolated from purified splenic T-cells and hybridized to Affymetrix oligonucleotide microarrays.

RESULTS

Relative to anesthesia, 116 genes after pneumoperitoneum and 398 genes after laparotomy showed a > or =2-fold change in expression at 12 hours. One hundred thirty-two genes after pneumoperitoneum and 157 genes after laparotomy met those criteria at 24 hours. Comparing surgical modalities, 177 genes were increased and 15 decreased > or =2-fold after laparotomy relative to pneumoperitoneum at 12 hours, compared with 44 and 5 genes respectively at 24 hours. Expression changes for 8 genes were validated by quantitative real-time polymerase chain reaction.

CONCLUSIONS

Laparotomy and pneumoperitoneum alter splenic T-cell gene expression, with the most extensive changes occurring 12 hours after laparotomy. This study is one of the first comprehensive genomic studies of the molecular effects of surgical manipulation on immune function. The genes identified are potential targets for modulating the immune response to surgery.

Hepatic carbohydrate metabolism in rats after laparotomy and laparoscopy

BACKGROUND

Portal venous and mesenteric blood flow are reduced by 40-60% in humans and animals during laparoscopic surgery compared to laparotomy. Little is known about whether these intraabdominal micro- and macrocirculatory changes are associated with alterations in the hepatic energy metabolism.

METHODS

We operated on male Sprague-Dawley rats, performing either laparoscopy (CO2, 6 mmHg; n = 27) or laparotomy (n = 28), and compared the results with two control groups: intraperitoneal (i.p.) endotoxin administration (n = 28, positive control) and anesthesia only (n = 28, negative control). We investigated the impact of the two different surgical techniques on daily food intake, body weight gain, glycogen content in the liver, levels of blood glucose, and liver function tests (LFTs) on postoperative days 1, 2, 4, and 8. Local (hepatic) and systemic inflammatory responses (interleukin-6 and tumor necrosis factor-alpha) during the postoperative time course were also determined. Data were analyzed using the Kruskal-Wallis test or univariate analysis of variance.

RESULTS

Body weight gain, food intake, liver and spleen weights, as well as LFTs [except aspartate aminotransferase (AST)] did not differ among the four groups. The significant increase in the AST level following laparoscopy compared to the anesthesia-only group was found on postoperative days 1 and 2; however, a similar difference was not detected after laparotomy or i.p. endotoxin injection. Laparoscopy showed no alterations in the hepatic glycogen stores compared to anesthesia only, whereas laparotomy and endotoxinemia significantly reduced the hepatic glycogen stores on postoperative days 2 and 4. The systemic postoperative inflammatory response did not differ between laparotomy and laparoscopy, but it was higher in both groups than in anesthesia only. In rats treated with endotoxin, the systemic inflammatory response was even higher than in the two surgical groups. The hepatic inflammatory response did not differ between the four groups.

CONCLUSION

This study shows a significant postoperative decrease in the hepatic glycogen content after laparotomy and i.p. endotoxin injection but not after laparoscopy. Food intake and inflammatory response cannot explain this difference between the two surgical groups, which suggests that alterations in the postsurgical hormonal stress response are the most likely explanation for these findings.

Stress response to laparoscopic liver resection

The magnitude of the systemic response is proportional to the degree of surgical trauma. Much has been reported in the literature comparing metabolic and immune responses, analgesia use, or length of hospital stay between laparoscopic and open procedures. In particular, metabolic and immune responses are represented by measuring various chemical mediators as stress responses. Laparoscopic procedures are associated with reduced operative trauma compared with open procedures, resulting in lower systemic response. As a result, laparoscopic procedures are now well accepted for both benign and malignant processes. Laparoscopic liver resection, specifically, is employed for symptomatic and some malignant tumors, following improvements in diagnostic accuracy, laparoscopic devices, and techniques. However, laparoscopic liver resection is still controversial in malignant disease because of complex anatomy, the technical difficulty of the procedure, and questionable indications. There are few reports describing the stress responses associated with laparoscopic liver resection, even though many studies reviewing stress responses have been performed recently in both humans and animal models comparing laparoscopic to conventional open surgery. Although this review examines stress response after laparoscopic liver resection in both an animal and human clinical model, further controlled randomized studies with additional investigations of immunologic parameters are needed to demonstrate the consequences of either minimally invasive surgery or open procedures on perioperative or postoperative stress responses for laparoscopic liver resection.