Immune and Inflammatory Responses of the Intestinal Mucosa following Extended Liver Radiofrequency Ablation

Inflammation-attenuating effect of carbon dioxide versus room-air environment in a rat laparotomy model

BACKGROUND

The mechanism by which laparoscopic operations induce lower post-operative inflammatory response compared to open surgery was investigated with regard to the effect of the type of gas environment.

METHODS

Rats were subjected to midline laparotomy at either CO2 (group CO2) or room-air environment (group Air) or to anesthesia only (group Control) under atmospheric pressure conditions. At various timepoints after surgery (1, 3, 6, 24, or 48 h), the expression of inflammation biomarkers interleukin-6 (IL-6), tumor necrosis factor-α (TNFα), and nuclear factor-κΒ (NFκΒ) were assessed immunohistochemically in tissue samples excised from the liver, intestine, and kidneys, accompanied by histopathologic analysis, and their levels were measured by ELISA in blood samples.

RESULTS

Tissue expression of IL-6, TNFα, and NFκΒ was downregulated in the liver and intestine in group CO2 compared to group Air and in the kidneys in group Air compared to group CO2. However, no differences were noted among groups regarding the histopathologic score of organ tissues and the blood serum levels of inflammation biomarkers.

CONCLUSION

Post-operative local inflammatory response was lower in intra-peritoneal organs of rats subjected to laparotomy at CO2 rather than room-air environment under atmospheric pressure conditions.

Gut Barrier Disruption Secondary to Radiofrequency-Assisted Liver Parenchyma Resection in a Porcine Model

BACKGROUND

Radiofrequency-assisted liver resection (RF-LR) techniques minimize intraoperative blood loss, while avoiding the Pringle maneuver. Both surgical excision and radiofrequency ablation of liver parenchyma compromise gut barrier function with subsequent bacterial translocation. The present study sought to investigate in a porcine model the impact of two RF-LR techniques on the integrity and inflammatory response of the gut barrier.

METHODS

Twenty-four pigs were subjected to either (a) partial hepatectomy (PH) employing the "sequential coagulate-cut" technique using a monopolar electrode (SCC group), the one using the bipolar Habib-4X device (group H), or the "crush-clamp" technique (group CC) or (b) sham operation (group Sham). At 48-h post-operation, ileal tissue was excised to be subjected to histopathologic examination, histomorphometric analysis, and immunohistochemical assessment of the mitotic and apoptotic activities and the expression of interleukin-6 (IL-6), tumor necrosis factor-α (TNFα), and nuclear factor-κB (NFκΒ).

RESULTS

Histopathologic score increased in all PH groups, being higher in group SCC, while lower in group H. Villous height decreased in group SCC only. Mitotic index decreased, while apoptotic index increased in all PH groups. An increase in tissue expression score was noted for IL-6 in group CC, for TNFα in all PH groups, being lower in group H compared to group CC, and for NFκB in all PH groups.

CONCLUSIONS

The Habib-4X technique for liver resection proved to preserve the integrity of gut barrier, being less injurious in the intestinal mucosa compared to the SCC and CC techniques.

Mucin 1 and interleukin-11 protein expression and inflammatory reactions in the intestinal mucosa of necrotizing enterocolitis children after surgery

BACKGROUND

Necrotizing enterocolitis (NEC) of the newborn is a frequently occurring clinical disease in infants. The mortality rate of NEC in premature infants is as high as 50%, and the morbidity rate is on the rise. NEC has already caused serious impacts on newborn survival and poses serious threats to both children and families.

AIM

To investigate the expression and significance of mucin 1 (MUC1) and interleukin-11 (IL-11) in the intestinal mucosa of infants with neonatal NEC after surgery.

METHODS

Forty-eight postoperative intestinal mucosal specimens from children with NEC (NEC group) and twenty-two intestinal mucosal specimens from children with congenital intestinal atresia (control group) were collected in our hospital. Immunohistochemical staining and Western blot analysis were used to examine the protein expression of MUC-1 and IL-11 in the two groups. The serum levels of tumor necrosis factor-α (TNF-α) and IL-1β in the two groups were measured by enzyme-linked immunosorbent assay, and the relationship between MUC-1 and IL-11 protein expression and serum TNF-α and IL-1β levels was analyzed by the linear correlation method.

RESULTS

The protein expression of MUC-1 and IL-11 in the NEC group was significantly lower than that in the control group, and the difference was statistically significant (P < 0.05). The levels of serum TNF-α and IL-1β in the NEC group were significantly higher than those in the control group (P < 0.05). The protein expression of MUC-1 and IL-11 in the NEC group negatively correlated with serum TNF-α and IL-1β levels (P < 0.05). There was a significant negative correlation between the protein expression of MUC-1 and IL-11 and the levels of serum TNF-α and IL-1β in the NEC group.

CONCLUSION

The protein expression of MUC1 and IL-11 in the intestinal mucosa of children with NEC is significantly downregulated after surgery. This downregulation may be involved in the pathogenesis of this disease and has a certain correlation with inflammatory response factors in children with NEC.

Influence of the heat irrigating effect of radiofrequency ablation on regional liver tissue in Bama miniature pigs

BACKGROUND

The results of the heat irrigating effect of radiofrequency ablation (RFA) are uncertain, and the accurate impact of the heat irrigating effect on regional liver tissue is unknown due to a lack of control experiments.

AIM

The aim of this study was to determine the influence of the heat irrigating effect of RFA on regional liver tissue in Bama miniature pigs.

METHODS

Eight Bama miniature pigs were randomly divided into the observation group (group A) and the control group (group B), with 4 pigs/group. An RFA electrode needle was implanted near the hepatic segment vasculature (3-5 mm from the hepatic segment portal vein) under ultrasound guidance in group A. Similarly, an RFA electrode needle was implanted far from the hepatic segment vasculature (8-10 mm from the hepatic segment portal vein) in group B. The left internal lobe and right medial lobe were chosen as RFA sites in each pig. RFA was performed at the left internal lobe on day one in each pig, and at the right medial lobe 7 d later. Each RFA lasted 12 min. The general status of the pigs and serious complications were observed during the perioperative period. The pigs were sacrificed and the livers were removed immediately after RFA on the eighth day. The samples were roughly observed. Hematoxylin-eosin and Ki67 staining, as well as TUNEL detection, were performed on the tissue sections.

RESULTS

All 8 animals successfully underwent ultrasound-guided RFA. No serious complications, such as massive hemorrhage, biliary fistula, severe pleural effusion, pneumothorax, peripheral organ failure, or renal failure occurred in any of the animals during the perioperative period. The RFA coagulative necrosis lesion was spherical and the surrounding liver tissue showed an inflammatory response. The difference in the Suzuki score of the liver tissue surrounding the ablated portal vein, and its distal area between groups A and B, was statistically significant (P < 0.05). More apoptotic cells were seen in liver tissue surrounding the ablated portal vein and its distal area in group A, while fewer apoptotic cells in the same area were seen in group B. The difference in the apoptotic index of the above area between group A and group B was statistically significant (P < 0.05). Cells staining positive for Ki67 were observed in liver tissue at the left internal lobe around the ablated portal vein and its distal area in group A. No Ki67 staining positive cells were observed in other tissue sections. The difference in the Ki67 staining positive index in the above area was statistically significant (P < 0.05) between group A and group B.

CONCLUSION

Changes as a result of thermal damage occur in liver tissue around the ablated portal vein and its distal area due to the heat irrigating effect when the RFA electrode tip is close to (< 5 mm) the portal vein.

T-cell activation and immune memory enhancement induced by irreversible electroporation in pancreatic cancer

Background

Irreversible electroporation is shown to induce immune changes in pancreatic cancer while the histology evidences are still lacking. The aim of this study is to show the immune changes in histology and explore whether irreversible electroporation (IRE) can induce immunogenic cell death (ICD) of tumor cells and activate specific immune responses.

Methods

Subcutaneous and orthotopic pancreatic cancer models were established and used to evaluate the effect of immune modulation of IRE. The infiltration of T cells was assessed in several tissue samples before and after IRE. Abscopal effect was then assessed by comparing the tumor growth of subcutaneous tumors after in situ ablation with IRE or exposure to tumor culture supernatant (TSN) of IRE‐treated Pan02. The expression of damage‐associated molecular patterns (DAMPs) of tumor cells after IRE was detected in vitro.

Results

IRE could significantly suppress the tumor growth and increase the infiltration of CD8⁺ T cells. After ablation with IRE or stimulation with TSN of Pan02 treated by IRE, the growth of untreated tumor was suppressed and the effector CD8⁺ T cells and memory T cells increased significantly in mice. Additionally, the inhibition effect of tumor growth increased along with the increasing strength levels of electroporation. IRE induced ICD of tumor cells by increasing the synthesis and secretion of DAMPs.

Conclusions

IRE induced local immunomodulation by increasing specific T cells infiltration. Through enhancing specific immune memory, IRE not only led a complete tumor regression in suit, but also induced abscopal effect, suppressing the growth of the latent lesions.

In situ thermal ablation augments antitumor efficacy of adoptive T cell therapy

Purpose: The aim of this study is to investigate whether radiofrequency ablation (RFA) improves the efficacy of adoptive T cell immunotherapy in preclinical mouse cancer models.Method: Mice implanted subcutaneously (sc) with syngeneic colon adenocarcinoma or melanoma were treated with sub-curative in situ RFA (90 °C, 1 min). Trafficking of T cells to lymph nodes (LN) or tumors was quantified by homing assays and intravital microscopy (IVM) after sham procedure or RFA. Expression of trafficking molecules (CCL21 and intercellular adhesion molecule-1 [ICAM-1]) on high endothelial venules (HEV) in LN and tumor vessels was evaluated by immunofluorescence microscopy. Tumor-bearing mice were pretreated with RFA to investigate the therapeutic benefit when combined with adoptive transfer of in vitro-activated tumor-specific CD8⁺ T cells.Results: RFA increased trafficking of naïve CD8⁺ T cells to tumor-draining LN (TdLN). A corresponding increase in expression of ICAM-1 and CCL21 was detected on HEV in TdLN but not in contralateral (c)LN. IVM revealed that RFA substantially enhanced secondary firm arrest of lymphocytes selectively in HEV in TdLN. Furthermore, strong induction of ICAM-1 in tumor vessels was associated with significantly augmented trafficking of adoptively transferred in vitro-activated CD8⁺ T cells to tumors after RFA. Finally, preconditioning tumors with RFA augmented CD8⁺ T cell-mediated apoptosis of tumor targets and delayed growth of established tumors when combined with adoptive T cell transfer immunotherapy.Conclusions: These studies suggest that in addition to its role as a palliative therapeutic modality, RFA may have clinical potential as an immune-adjuvant therapy by augmenting the efficacy of adoptive T cell therapy.