Trocar Site HERnias After Bariatric Laparoscopic Surgery (HERBALS): a Prospective Cohort Study

Background

The exact prevalence of trocar site hernias after bariatric procedures is not yet known. Recent metaanalysis data indicated concerning rates of up to 25%. We conducted a prospective cohort study to estimate the prevalence and analyze the role of fascia closure in the development of trocar hernias.

Method

A total of 365 patients who were operated for obesity in our department between 2009 and 2018 were included. All patients were invited for a follow-up ultrasonography scan in order to detect abdominal wall defects. The role of intraoperative fascia closure in the development of trocar site hernias was evaluated, and a logistic regression analysis was performed to detect potential risk factors.

Results

The overall prevalence of trocar hernias detected by ultrasonography was 34%. The prevalence of abdominal wall defects in patients who received a fascia closure was 37% compared with 34% in patients who did not receive a fascia closure (p = 0.37). The only factor that was associated with a higher risk for trocar site hernias was high excessive weight loss (p = 0.05).

Conclusion

Trocar site hernias are an underestimated complication of minimally invasive, multiportal bariatric surgery, and the prevalence of asymptomatic hernias is probably higher than initially expected. In this study, fascia closure did not protect against trocar hernias. However, opposing evidence from similar trials suggests closing the fascia. This clinical problem should therefore be further assessed in a prospective randomized setting.

Correction to: Trocar Site Hernias in Bariatric Surgery-an Underestimated Issue: a Qualitative Systematic Review and Meta-Analysis

The review was not registered for systematic reviews and meta-analyses, and should be disregarded.

Trocar Site Hernias in Bariatric Surgery-an Underestimated Issue: a Qualitative Systematic Review and Meta-Analysis

The reported incidence of trocar site hernias in bariatric surgery ranges between 0.5 and 3%. The best available evidence derives from retrospective studies analysing prospective databases, thus including only patients who presented with symptoms or received surgical treatment due to trocar site hernias after a laparoscopic bariatric procedure. A systematic literature research was conducted up until September 2017. Search strategies included proper combinations of the MeSH terms 'laparoscopy' and 'bariatric surgery', 'trocar/port' and 'hernia'. Searches were not limited by publication type or language. The review was registered in PROSPERO (ID 85102) and performed according to the PRISMA guidelines. Sixty-eight publications were included. Pooled hernia incidence was 3.22 (range 0-39.3%). Thirteen trials reported systematic closure of the fascia; 12 trials reported no closure. Data availability did not allow for pooling to calculate relative risk. Higher BMI and specific hernia examination using imaging modalities were associated with a significantly higher incidence of trocar site hernias. Studies dedicated to detection of TsH reported a pooled incidence of 24.5%. Trocar site hernias are an underestimated complication of minimally invasive multiportal bariatric surgery. While high-quality trials are not available allowing for a precise calculation of the incidence, existing data are indicative of very high incidence rates. Risk factors for developing a trocar site hernia in bariatric surgery have not yet been systematically analysed. Prospective studies in this field are necessary.

Characterization of Interleukin-15-Transpresenting Dendritic Cells for Clinical Use

Personalized dendritic cell- (DC-) based vaccination has proven to be safe and effective as second-line therapy against various cancer types. In terms of overall survival, there is still room for improvement of DC-based therapies, including the development of more immunostimulatory DC vaccines. In this context, we redesigned our currently clinically used DC vaccine generation protocol to enable transpresentation of interleukin- (IL-) 15 to IL-15Rβγ-expressing cells aiming at boosting the antitumor immune response. In this study, we demonstrate that upon electroporation with both IL-15 and IL-15Rα-encoding messenger RNA, mature DC become highly positive for surface IL-15, without influencing the expression of prototypic mature DC markers and with preservation of their cytokine-producing capacity and their migratory profile. Functionally, we show that IL-15-transpresenting DC are equal if not better inducers of T-cell proliferation and are superior in tumor antigen-specific T-cell activation compared with DC without IL-15 conditioning. In view of the clinical use of DC vaccines, we evidence with a time- and cost-effective manner that clinical grade DC can be safely engineered to transpresent IL-15, hereby gaining the ability to transfer the immune-stimulating IL-15 signal towards antitumor immune effector cells.

Natural killer cell immune escape in acute myeloid leukemia

As central players of the innate immune system, natural killer (NK) cells can exert direct and indirect anti-tumor effects via their cytotoxic and immune regulatory capacities, pivotal in the induction of an effective adaptive anti-tumor immune response. Hence, NK cells are considered to be important in the immune surveillance of cancer. In acute myeloid leukemia (AML) patients, however, significantly impaired NK cell functions can facilitate escape from immune surveillance and affect patient outcome. Here, we review various NK cell defects and AML evasion mechanisms to escape from NK cell-mediated immune surveillance and we discuss NK cell-related parameters as prediction factors of AML patient outcome. On the basis of these observations, novel immunotherapeutic strategies capitalizing on the potentiation of NK cell functions have emerged in AML immunotherapy, as discussed in this review. Increased knowledge on AML escape routes from NK cell immune surveillance will further aid in the design of novel NK cell-based immunotherapy approaches for the treatment of AML.

Quantification of IFN-gamma produced by human purified NK cells following tumor cell stimulation: comparison of three IFN-gamma assays

Interferon (IFN)-gamma released by natural killer (NK) cells has become a subject of major interest, given its importance in bridging the innate and adaptive immune system. Interestingly, reports concerning tumor cell stimulation of NK cells show divergent data on which stimuli induce IFN-gamma production. Here, the question remains whether tumor cell recognition is sufficient to trigger IFN-gamma or whether a second signal is required such as type I IFN. While IFN-gamma detection methods are abundantly used with peripheral blood mononuclear cells or purified T cell fractions as responder populations, only limited data is available about comparison of these assays with purified NK cells. In this study, we assessed the relationship between stimulation of human purified resting peripheral blood NK cells with one (tumor cell or IFN-alpha) and two (tumor cell+IFN-alpha) signals by measuring IFN-gamma using three different assays. We performed the enzyme-linked immunosorbent assay (ELISA), the enzyme-linked immunospot (ELISPOT) assay and intracellular cytokine staining (ICS) assay in parallel per donor and determined whether there was a correlation between these assays. Our results show that two-signal stimulation of human resting NK cells induces significantly more IFN-gamma as compared to one-signal stimulation, readily picked up by all assays. Moreover, statistical analysis points towards a positive correlation between these assays for IFN-gamma produced following two-signal stimulation. Importantly, we show that tumor cell stimulation alone is enough to trigger secretion of IFN-gamma, but this finding was only evidenced by ELISPOT. These results reveal that the choice of IFN-gamma detection method can markedly influence the outcome regarding induction of NK cell IFN-gamma by tumor cells.