Perioperative use of a neutrophil elastase inhibitor in video-assisted thoracoscopic oesophagectomy for cancer

Targeting neutrophil elastase is a promising direction for future cancer treatment

Neutrophil elastase (NE) is a proteolytic enzyme released extracellular during the formation of neutrophil extracellular traps (NETs) through degranulation. In addition to participating in the body's inflammatory response, NE also plays an important role in cancer. It can promote tumor proliferation, migration, and invasion, induce epithelial-mesenchymal transition (EMT), and change the tumor microenvironment (TME) to promote tumor progression. Concurrently, NE promotes systemic treatment resistance by inducing EMT. However, it can also selectively kill cancer cells and attenuate tumor development. Sivelestat is a specific NE inhibitor that can be used in the perioperative period of esophageal cancer patients to reduce the incidence of postoperative complications after esophagectomy. In addition, the combination of sivelestat and trastuzumab can enhance the efficacy of human epidermal growth factor receptor 2(HER 2) positive breast cancer patients. Meanwhile, targeting the human antibody domains and fragments of NE is also a new way to treat cancer and inflammation-related diseases. This review provides valuable insights into the role of NE in cancer treatment. Additionally, we discuss the challenges associated with the clinical application of sivelestat. By shedding light on the promising potential of NE, this review contributes to the advancement of cancer treatment strategies.

NET-targeted therapy: effects, limitations, and potential strategies to enhance treatment efficacy

Neutrophil extracellular traps (NETs) are complex structures released by activated neutrophils during inflammatory responses. Due to their unique potential for causing tissue damage and modulating immune responses, there is increasing interest in studying these structures as potential targets for the treatment of infectious diseases, autoimmune diseases, and cancer. However, therapeutic targeting of NETs might trigger deleterious effects that may limit treatment efficacy. NET disruption may increase the microbial load in infection; in autoimmunity, NET targeting might impair peripheral tolerance, but it might reduce adaptive immune responses in cancer. In this review, we explore the therapeutic and deleterious effects of NET-targeted therapy while shedding light on novel strategies to overcome treatment-related limitations and enhance treatment efficacy.

The fragility of significant results from randomized controlled trials in esophageal surgeries

While randomized controlled trials (RCTs) are regarded as one of the highest forms of clinical research, the robustness of their P values can be difficult to ascertain. Defined as the minimum number of patients in a study arm that would need to be changed from a non-event to event for the findings to lose significance, the Fragility Index is a method for evaluating results from these trials. This study aims to calculate the Fragility Index for trials evaluating perioperative esophagectomy-related interventions to determine the strength of RCTs in this field. MEDLINE and EMBASE were searched for RCTs related to esophagectomy that reported a significant dichotomous outcome. Two reviewers independently screened articles and performed the data extractions with risk of bias assessment. The Fragility Index was calculated using a two-tailed Fisher's exact test. Bivariate correlation was conducted to evaluate associations between the Fragility Index and study characteristics. 41 RCTs were included, and the median sample size was 80 patients [Interquartile range (IQR) 60-161]. Of the included outcomes, 29 (71%) were primary, and 12 (29%) were secondary. The median Fragility Index was 1 (IQR 1-3), meaning that by changing one patient from a non-event to event, the results would become non-significant. Fragility Index was correlated with P value, number of events, and journal impact factor. The RCTs related to esophagectomy did not prove to be robust, as the significance of their results could be changed by altering the outcome status of a handful of patients in one study arm.

Neutrophil extracellular traps facilitate cancer metastasis: cellular mechanisms and therapeutic strategies

Background

The formation of neutrophil extracellular traps (NETs) was initially discovered as a novel immune response against pathogens. Recent studies have also suggested that NETs play an important role in tumor progression. This review summarizes the cellular mechanisms by which NETs promote distant metastasis and discusses the possible clinical applications targeting NETs.

Method

The relevant literature from PubMed and Google Scholar (2001–2021) have been reviewed for this article.

Results

The presence of NETs has been detected in various primary tumors and metastatic sites. NET-associated interactions have been observed throughout the different stages of metastasis, including initial tumor cell detachment, intravasation and extravasation, the survival of circulating tumor cells, the settlement and the growth of metastatic tumor cells. Several in vitro and in vivo studies proved that inhibiting NET formation resulted in anti-cancer effects. The biosafety and efficacy of some NET inhibitors have also been demonstrated in early phase clinical trials.

Conclusions

Considering the role of NETs in tumor progression, NETs could be a promising diagnostic and therapeutic target for cancer management. However, current evidence is mostly derived from experimental models and as such more clinical studies are still needed to verify the clinical significance of NETs in oncological settings.

Neutrophil Extracellular Traps in Cancer Therapy Resistance

Neutrophils and their products are increasingly recognized to have a key influence on cancer progression and response to therapy. Their involvement has been shown in nearly every aspect of cancer pathophysiology with growing evidence now supporting their role in resistance to a variety of cancer therapies. Recently, the role of neutrophils in cancer progression and therapy resistance has been further complicated with the discovery of neutrophil extracellular traps (NETs). NETs are web-like structures of chromatin decorated with a variety of microbicidal proteins. They are released by neutrophils in a process called NETosis. NET-dependent mechanisms of cancer pathology are beginning to be appreciated, particularly with respect to tumor response to chemo-, immuno-, and radiation therapy. Several studies support the functional role of NETs in cancer therapy resistance, involving T-cell exhaustion, drug detoxification, angiogenesis, the epithelial-to-mesenchymal transition, and extracellular matrix remodeling mechanisms, among others. Given this, new and promising data suggests NETs provide a microenvironment conducive to limited therapeutic response across a variety of neoplasms. As such, this paper aims to give a comprehensive overview of evidence on NETs in cancer therapy resistance with a focus on clinical applicability.

Neutrophil Extracellular Traps in Digestive Cancers: Warrior or Accomplice

Characterized as a complex of extracellular DNA fibers and granule proteins, neutrophil extracellular traps (NETs) are generated specifically by neutrophils which play a critical role in host defense and immune regulation. NETs have been initially found crucial for neutrophil anti-microbial function. Recent studies suggest that NETs are involved in tumorigenesis and cancer progression. However, the function of NETs in cancer remains unclear, which might be due to the variation of research models and the heterogeneity of cancers. Although most of malignant tumors have similar biological behaviors, significant differences indeed exist in various systems. Malignant tumors of the digestive system cause the most incidence and mortality of cancer worldwide. In this review, we would focus on research developments on NETs in digestive cancers to provide insights on their role in digestive cancer progression and future research directions.

Pharmacological treatment to reduce pulmonary morbidity after esophagectomy

Esophagectomy for esophageal cancer is one of the most invasive procedures in gastrointestinal surgery. An invasive surgical procedure causes postoperative lung injury through the surgical procedure and one-lung ventilation during anesthesia. Lung injury developed by inflammatory response to surgical insults and oxidative stress is associated with pulmonary morbidity after esophagectomy. Postoperative pulmonary complications negatively affect the long-term outcomes; therefore, an effort to reduce lung injury improves overall survival after esophagectomy. Although significant evidence has not been established, various pharmacological treatments for reducing lung injury, such as administration of a corticosteroid, neutrophil elastase inhibitor, and vitamins are considered to have efficacy for pulmonary morbidity. In this review we survey the following topics: mediators during the perioperative periods of esophagectomy and the efficacy of pharmacological therapies for patients with esophagectomy on pulmonary complications.

Administration of Corticosteroids, Ascorbic Acid, and Thiamine Improves Oxygenation after Thoracoscopic Esophagectomy

PURPOSE

The activity of corticosteroids, ascorbic acid, and thiamine against oxidative and inflammatory responses was evaluated in patients undergoing esophagectomy. This study was undertaken to investigate the effect of this combined therapy on lung dysfunction following esophagectomy.

METHODS

In this retrospective before-after study, we compared the clinical course of consecutive patients undergoing thoracoscopic esophagectomy treated with the combination of corticosteroids, ascorbic acid, and thiamine between June and December 2018 with a control group treated with corticosteroids alone between January 2016 and May 2018. Outcomes included oxygenation (arterial partial pressure of oxygen (PaO2)/fractional concentration of inspired oxygen (FiO2) ratios), duration of mechanical ventilation and intensive care unit (ICU) length of stay.

RESULTS

In all, 17 patients were included in this study (6 in the combination therapy group and 11 patients in the control group). Mean PaO2/FiO2 ratios in the combined therapy group were significantly higher than in the control group at all points during the observation period (p <0.001). In the combined therapy group, the duration of mechanical ventilation and ICU stay were significantly shorter (p <0.001, p = 0.009).

CONCLUSIONS

This study suggests that combined therapy including corticosteroids, ascorbic acid, and thiamine may be effective in improving oxygenation after esophagectomy. Additional studies are required to confirm these preliminary findings.

Combination of sivelestat and N-acetylcysteine alleviates the inflammatory response and exceeds standard treatment for acetaminophen-induced liver injury

Hepatocyte death during acetaminophen (APAP) intoxication elicits a reactive inflammatory response, with hepatic recruitment of neutrophils and monocytes, which further aggravates liver injury. Neutrophil elastase (NE), secreted by activated neutrophils, carries degradative and cytotoxic functions and maintains a proinflammatory state. We investigated NE as a therapeutic target in acetaminophen-induced liver injury (AILI). C57BL/6 mice were administered a toxic dose of APAP, 2 h prior to receiving the NE inhibitor sivelestat, N-acetylcysteine (NAC), or a combination therapy, and were euthanized after 24 and 48 h. Upon APAP overdose, neutrophils and monocytes infiltrate the injured liver, accompanied by increased levels of NE. Combination therapy of NAC and sivelestat significantly limits liver damage, as evidenced by lower serum transaminase levels and less hepatic necrosis compared to mice that received APAP only, and this to a greater extent than NAC monotherapy. Lower hepatic expression of proinflammatory markers was observed in the combination treatment group, and flow cytometry revealed significantly less monocyte influx in livers from mice treated with the combination therapy, compared to untreated mice and mice treated with NAC only. The potential of NE to induce leukocyte migration was confirmed in vitro. Importantly, sivelestat did not impair hepatic repair. In conclusion, combination of NE inhibition with sivelestat and NAC dampens the inflammatory response and reduces liver damage following APAP overdose. This strategy exceeds the standard of care and might represent a novel therapeutic option for AILI.

Prophylactic sivelestat for esophagectomy and in-hospital mortality: a propensity score-matched analysis of claims database

PURPOSE

Transthoracic esophagectomy is an invasive surgery, and the excessive surgical stress produces inflammatory cytokines, which provoke acute respiratory distress syndrome (ARDS). Sivelestat sodium hydrate-a selective neutrophil elastase inhibitor-is used to treat or prevent ARDS in patients undergoing esophagectomy, although clear evidence is lacking. We investigated the benefits and risk of prophylactic sivelestat.

METHODS

This retrospective study used an administrative claims database in Japan. Adult patients who underwent transthoracic esophagectomy from 2010 to 2016 were identified and divided into a prophylactic sivelestat use group and a non-prophylactic use group that included both non-users and therapeutic users. The primary outcome was all-cause in-hospital mortality, and a secondary outcome included the proportion of ARDS. We used 1:1 propensity score matching. For sensitivity analyses, we conducted a 1:2 propensity score matching analysis and several analyses with various patient inclusion criteria.

RESULTS

Of the 3391 patients with esophagectomy, 621 received prophylactic sivelestat. On unadjusted analysis, the sivelestat group had a higher proportion of in-hospital mortality (5.3% vs. 2.9%) compared with the control group. We created a matched cohort of 615 pairs, whose baseline characteristics were well balanced. On adjusted analysis using propensity score matching, prophylactic sivelestat administration was not associated with decreased in-hospital mortality [adjusted odds ratio (aOR) 1.65; 95% confidence interval (CI) 0.95-2.88], ARDS rate (aOR 1.25; 95% CI 0.49-3.17). The findings were also consistent with other sensitivity analyses.

CONCLUSION

Because mortality and postoperative complications were similar, our findings do not support prophylactic sivelestat administration for patients undergoing esophagectomy.

Predictors of the therapeutic effect of sivelestat in patients with acute lung injury associated with systemic inflammatory response syndrome

Background

Sivelestat, a neutrophil elastase inhibitor, was previously approved in Japan for the treatment of acute lung injury associated with systemic inflammatory response syndrome. However, sivelestat produced inconsistent therapeutic benefits. This study aimed to identify factors predicting the therapeutic effects of sivelestat.

Methods

We enrolled 53 mechanically ventilated patients who received sivelestat. The patients were classified as effective (n = 28) if they were weaned from the ventilator within 28 days, or as ineffective groups (n = 25). Patient characteristics were compared between these groups and multivariate logistic regression analysis was used to identify predictive factors. A validation study was then conducted in sivelestat-free patients.

Results

A high red blood cell count and low hydrogen ion concentration were significantly associated with a higher ventilator weaning rate in patients receiving sivelestat. The validation study revealed that the hydrogen ion concentration value also significantly associated with ventilator weaning in patients who did not receive sivelestat.

Conclusions

Although hydrogen ion concentration was inversely associated with the ventilator weaning rate, it did not predict sivelestat efficacy. This study indicated that acute lung injury patients with a high red blood cell count would derive the most benefit from sivelestat administration.

Effects of neutrophil elastase inhibitor in patients undergoing esophagectomy: A systematic review and meta-analysis

AIM: To evaluate the benefit and safety of sivelestat (a neutrophil elastase inhibitor) administration in patients undergoing esophagectomy.

METHODS: Online databases including PubMed, EMBASE, the Cochrane Library, Web of Knowledge, and Chinese databases (Wanfang database, VIP and CNKI) were searched systematically up to November 2013. Randomized controlled trials and high-quality comparative studies were considered eligible for inclusion. Three reviewers evaluated the methodological quality of the included studies, and Stata 12.0 software was used to analyze the extracted data. The risk ratio (RR) was used to express the effect size of dichotomous outcomes, and mean difference (MD) or standardized mean difference was used to express the effect size of continuous outcomes.

RESULTS: Thirteen studies were included in this systematic review and nine studies were included in the meta-analysis. The duration of mechanical ventilation was significantly decreased in the sivelestat group on postoperative day 5 [I² = 76.3%, SMD = -1.41, 95%CI: -2.63-(-0.19)]. Sivelestat greatly lowered the incidence of acute lung injury in patients after surgery (I² = 0%, RR = 0.27, 95%CI: 0.08-0.93). However, it did not decrease the incidence of pneumonia, intensive care unit stay or postoperative hospital stay, and did not increase the incidence of complications such as anastomotic leakage, recurrent nerve palsy, wound infection, sepsis and catheter-related fever.

CONCLUSION: A neutrophil elastase inhibitor is beneficial in patients undergoing esophagectomy. More high quality, large sample, multi-center and randomized controlled trials are needed to validate this effect.

Neutrophil extracellular traps in cancer progression

Neutrophils are being increasingly recognized as an important element in tumor progression. They have been shown to exert important effects at nearly every stage of tumor progression with a number of studies demonstrating that their presence is critical to tumor development. Novel aspects of neutrophil biology have recently been elucidated and its contribution to tumorigenesis is only beginning to be appreciated. Neutrophil extracellular traps (NETs) are neutrophil-derived structures composed of DNA decorated with antimicrobial peptides. They have been shown to trap and kill microorganisms, playing a critical role in host defense. However, their contribution to tumor development and metastasis has recently been demonstrated in a number of studies highlighting NETs as a potentially important therapeutic target. Here, studies implicating NETs as facilitators of tumor progression and metastasis are reviewed. In addition, potential mechanisms by which NETs may exert these effects are explored. Finally, the ability to target NETs therapeutically in human neoplastic disease is highlighted.

Thoracoscopic esophagectomy using prone positioning

Thoracotomic esophagectomy followed by cervical and abdominal procedures has been conventionally performed as the best curable operative procedure for treating invasive thoracic esophageal carcinoma. Despite improvements in the survival rate, the procedure is associated with significant operative morbidity and mortality rates due to the extreme invasiveness of an extensive dissection of the lymph nodes. Minimally invasive esophagectomy (MIE) was developed to reduce surgical invasiveness. Recently, the use of thoracoscopic esophagectomy performed in the prone position has stimulated new interest in minimally invasive approaches. However, the advantages and disadvantages of this technique are not well known. In this review, the literature to date, including series and comparative studies of minimally invasive esophagectomy performed in the prone position, is summarized, and the various lessons learned and controversies surrounding this technique are addressed.

Strategies to reduce pulmonary complications after esophagectomy

Esophagectomy, the surgical removal of all or part of the esophagus, is a surgical procedure that is associated with high morbidity and mortality. Pulmonary complications are an especially important postoperative problem. Therefore, many perioperative strategies to prevent pulmonary complications after esophagectomy have been investigated and introduced in daily clinical practice. Here, we review these strategies, including improvement of patient performance and technical advances such as minimally invasive surgery that have been implemented in recent years. Furthermore, interventions such as methylprednisolone, neutrophil elastase inhibitor and epidural analgesia, which have been shown to reduce pulmonary complications, are discussed. Benefits of the commonly applied routine nasogastric decompression, delay of oral intake and prophylactic mechanical ventilation are unclear, and many of these strategies are also evaluated here. Finally, we will discuss recent insights and new developments aimed to improve pulmonary outcomes after esophagectomy.

Neutrophil elastase inhibitor sivelestat attenuates perioperative inflammatory response in pediatric heart surgery with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) evokes activation of a systemic inflammatory response. Sivelestat has been used clinically to treat acute lung injury associated with systemic inflammatory response syndrome. This prospective, doubleblind, randomized study was designed to evaluate the effects of sivelestat in the perioperative period of elective pediatric open-heart surgery with CPB. Twenty-six consecutive pediatric patients weighing between 5 and 10 kg and undergoing open-heart surgery with CPB were divided into a sivelestat group (n = 13) and a control group (n = 13). The patients in the sivelestat group were administered a continuous intravenous infusion of 0.2 mg/kg/hour of sivelestat, and the patients in the control group were administered the same volume of 0.9% saline from the initiation of CPB to 24 hours after surgery. Blood samples were drawn for the measurement of cytokines, polymorphonuclear elastase (PMN-E), white blood cell count (WBC), neutrophil count (NC), and C-reactive protein (CRP). There were no significant differences in cytokine data between the two groups. The peak PMN-E and WBC levels were significantly increased in the control group (P = 0.049, P = 0.039). The WBC and NC levels immediately after surgery in the control group were significantly greater than those in the sivelestat group (P = 0.049, P = 0.044). The peak CRP level in the control group was significantly greater than the sivelestat group (P = 0.04), and the CRP level on postoperative day 4 in the control group was significantly greater than in the sivelestat group (P = 0.014). This study showed that sivelestat attenuates the perioperative inflammatory response in pediatric heart surgery with CPB.

The impact of tidal volume on pulmonary complications following minimally invasive esophagectomy: a randomized and controlled study

BACKGROUND

Minimally invasive esophagectomy (MIE) has been advantageous for lowering pulmonary complications compared with open approaches.(1) However, pulmonary complications remain the most common morbidity after surgical resection of esophageal cancer.(2,3) The aim of this prospective, randomized, controlled, clinical trial was designed to see whether low tidal volume (VT) could further minimize pulmonary complications after MIE.

METHODS

Between June 2011 and July 2012, a total of 101 patients who underwent MIE received left-lung ventilation during thoracoscopic esophagectomy. All patients received left-lung ventilation during thoracoscopic esophagectomy. Patients were randomly assigned to a low VT (5 mL/kg + 5 cm H2O positive end-expiratory pressure) preserved ventilation (PV) group (n = 53) and a conventional VT (8 mL/kg) controlled ventilation (CV) group (n = 48) in the thoracic stage. Alveolar lavage fluid was harvested from the ventilated lung at intubation and at 18 hours after surgery for analysis of interleukin (IL)-1ß, IL-6, and IL-8 levels. Clinical characteristics, including patient demographics, operation features, and changes in oxygenation index, were recorded and analyzed. Pulmonary complications were identified and statistically compared between the 2 groups.

RESULTS

The clinical characteristics and operation features were comparable between the 2 groups. IL-1ß, IL-6, and IL-8 expressions in preoperative alveolar lavage fluid were similar between the 2 groups. Significantly lower IL expressions were observed in the PV group than those in the CV group at 18 hours after MIE (IL-1ß, 25.42 ± 31.01 vs 94.96 ± 118.24 pg/mL; IL-6, 30.86 ± 75.78 vs 92.99 ± 72.90 pg/mL; IL-8, 258.75 ± 188.24 vs 403.95 ± 151.44 pg/mL; all P < .05). The 18-hour postoperative oxygenation index was lower in the CV group than that in the PV group (292.85 ± 28.74 vs 326.35 ± 34.43; P = .046). Pulmonary complications were observed in 18 cases of our series, occurring more frequently on the ventilation side (right, 6 cases; and left, 12 cases). All patients were cured by conservative therapy without severe sequelae. The occurrence of pulmonary complications in the PV group was lower than that in the CV group (9.43% vs 27.08%; P = .021).

CONCLUSIONS

Lung injury due to intraoperative single-lung ventilation may contribute to pulmonary complications after MIE. Low VT ventilation could decrease ventilation-associated lung inflammation, thus minimizing pulmonary complications after MIE. Further studies, based on a larger volume of populations, are required to confirm these findings.

Effect of early enteral nutrition on postoperative nutritional status and immune function in elderly patients with esophageal cancer or cardiac cancer

OBJECTIVE

To explore the effect of early enteral nutrition (EN) on postoperative nutritional status, intestinal permeability, and immune function in elderly patients with esophageal cancer or cardiac cancer.

METHODS

A total of 96 patients with esophageal cancer or cardiac cancer who underwent surgical treatment in our hospital from June 2007 to December 2010 were enrolled in this study. They were divided into EN group (n=50) and parenteral nutrition (PN) group (n=46) based on the nutrition support modes. The body weight, time to first flatus/defecation, average hospital stay, complications and mortality after the surgery as well as the liver function indicators were recorded and analyzed. Peripheral blood samples were collected on the days 1, 4 and 7 after surgery. The plasma diamine oxidase (DAO) activity and D-lactate level were determined to assess the intestinal permeability. The plasma endotoxin levels were determined using dynamic turbidimetric assay to assess the protective effect of EN on intestinal mucosal barrier. The postoperative blood levels of inflammatory cytokines and immunoglobulins were determined using enzyme-linked immunosorbent assay (ELISA).

RESULTS

After the surgery, the time to first flatus/defecation, average hospital stay, and complications were significantly less in the EN group than those in the PN group (P<0.05), whereas the EN group had significantly higher albumin levels than the PN group (P<0.05). On the 7th postoperative day, the DAO activity, D-lactate level and endotoxin contents were significantly lower in the EN group than those in the PN group (all P<0.05). In addition, the EN group had significantly higher IgA, IgG, IgM, and CD4 levels than the PN group (P<0.05) but significantly lower IL-2, IL-6, and TNF-α levels (P<0.05).

CONCLUSIONS

In elderly patients with esophageal cancer or cardiac cancer, early EN after surgery can effectively improve the nutritional status, protect intestinal mucosal barrier (by reducing plasma endoxins), and enhance the immune function.

Surgical quality of care in esophageal malignancies

Aim: Esophagectomy is the primary surgical treatment for localized malignant neoplasms of the esophagus, and while outcomes have shown that substantial improvement has been made, the ceiling for improvement is still high. Methods: A total of 2506 publications published from January 2002 to March 2012 were identified from PubMed, MEDLINE and the Cochrane Library using the keywords: ‘esophagectomy’, ‘esophagus’, ‘neoplasm’ and ‘cancer’ to identify quality key surgical articles in esophagectomy that were broken down into three groups: preoperative, intraoperative and postoperative care. Discussion: There have been limited preoperative surgical trials, mostly in preoperative antibiotic use, which have led to changes in surgical management. Key and substantial changes have occurred in the intraoperative management for esophageal malignancies around surgical anastomosis technique and anesthesia. Nutritional outcomes still remain a key challenge, and currently there is no established standard of care in the postoperative management of esophagectomy patients. Conclusion: We established quality parameters for leak rates, overall morbidity and mortality, and these form the foundation from which all esophageal surgeons should rank their results. We then utilized the techniques described above to maintain those rates or, better yet, to significantly improve those rates in each surgeons’ practice.