Liver radiofrequency ablation compromises the biological gut barrier

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.

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

Background and Aim

Extended liver radiofrequency ablation (RFA) has been shown to disrupt gut barrier integrity with subsequent bacterial translocation. The aim of the present project was to study the immune and inflammatory responses of the intestinal mucosa after extended RFA of the liver.

Methods

Twelve Wistar rats were either subjected to RFA of the left lateral hepatic lobe (approximately 30% of the liver mass) after midline laparotomy (group RFA, n = 6) or sham operation (group Sham, n = 6). Forty-eight hours later, ileal tissue specimens were excised for immunohistochemical assessment of CD68⁺ macrophages, CD4⁺ T-lymphocytes, CD8⁺ T-lymphocytes, mucosal addressin cell adhesion molecule-1 (MAdCAM-1), tumor necrosis factor-α (TNFα), interleukin-6 (IL-6), and nuclear factor-κB (NFκB) expression.

Results

Immune response biomarkers were upregulated in the RFA group. Expression of CD4⁺ and CD8⁺ T-lymphocytes was moderate, while that of CD68⁺ macrophages and MAdCAM-1 was high. Inflammatory response biomarkers were also upregulated in the RFA group. TNFα, IL-6, and NFκB expression was low, moderate, and high, respectively.

Conclusions

Extended liver RFA evokes both immune and inflammatory responses of the gut mucosa.

Early hemodynamic effects after extended liver radiofrequency ablation

BACKGROUND

The purpose of the present study was to assess early intestinal and systemic hemodynamic effects after extended radiofrequency ablation (RFA) of the liver in terms of investigating their potential contribution to gut barrier disruption.

MATERIALS AND METHODS

Ten rabbits were assigned to two groups of five animals each and were subjected to either 30% liver RFA (group RFA-1) or sham operation (group sham-1). Blood flow rate at the superior mesenteric artery (SMA) was monitored for 90 min after operation. Ileal tissue was excised at 48 h for histomorphometric and histopathologic analysis. Eight pigs were assigned to two groups of four animals each and were also subjected to either 30% liver RFA (group RFA-2) or sham operation (group sham-2). A panel of systemic hemodynamic parameters was serially measured up to 90 min after operation.

RESULTS

In group RFA-1, SMA blood flow rate was lower than that in group sham-1 throughout the study period. Intestinal mucosa atrophy and a deterioration of histopathologic profile were noted in group RFA-1. In group RFA-2, diastolic pulmonary artery pressure was lower (60-90 min), central venous pressure was gradually decreased, arterial pressure was higher (30-90 min), and systemic vascular resistance was higher (30-90 min) than those in group sham-2. No change was noted in the cardiac output.

CONCLUSIONS

In conclusion, SMA blood flow was reduced during the early post-RFA period, justifying an ischemic insult at the intestine. In addition, a gradual decrease of the preload was counterbalanced by an increase of systemic vascular resistance leaving the cardiac output unaffected.