Liver metastasis and ICAM-1 mRNA expression in the liver after carbon dioxide pneumoperitoneum in a murine model

Severe portal and systemic acidosis during CO2-laparoscopy compared to helium or gasless laparoscopy and laparotomy in a rodent model: an experimental study

BACKGROUND AND AIMS

This experimental study assesses the influence of different gases and insufflation pressures on the portal, central-venous and peripheral-arterial pH during experimental laparoscopy.

METHODS

Firstly, 36 male WAG/Rij rats were randomized into six groups (n = 6) spontaneously breathing during anaesthesia: laparoscopy using carbon dioxide or helium at 6 and 12 mmHg, gasless laparoscopy and laparotomy. 45 and 90 min after setup, blood was sampled from the portal vein, vena cava and the common femoral artery with immediate blood gas analysis. Secondly, 12 animals were mechanically ventilated at physiological arterial pH during 90 min of laparotomy (n = 6) or carbon dioxide laparoscopy at 12 mmHg (n = 6) with respective blood gas analyses.

RESULTS

Over time, in spontaneously breathing rats, carbon dioxide laparoscopy caused significant insufflation pressure-dependent portal acidosis (pH at 6 mmHg, 6.99 [6.95-7.04] at 45 min and 6.95 [6.94-6.96] at 90 min, pH at 12 mmHg, 6.89 [6.82-6.90] at 45 min and 6.84 [6.81-6.87] at 90 min; p < 0.05) compared to laparotomy (portal pH 7.29 [7.23-7.30] at 45 min and 7.29 [7.20-7.30] at 90 min; p > 0.05). Central-venous and peripheral-arterial acidosis was significant but less severely reduced during carbon dioxide laparoscopy. Laparotomy, helium laparoscopy and gasless laparoscopy showed no comparable acidosis in all vessels. Portal and central-venous acidosis during carbon dioxide laparoscopy at 12 mmHg was not reversible by mechanical hyperventilation maintaining a physiological arterial pH (pH portal 6.85 [6.84-6.90] (p = 0.004), central-venous 6.93 [6.90-6.99] (p = 0.004), peripheral-arterial 7.29 [7.29-7.31] (p = 0.220) at 90 min; Wilcoxon-Mann-Whitney test).

CONCLUSION

Carbon dioxide laparoscopy led to insufflation pressure-dependent severe portal and less severe central-venous acidosis not reversible by mechanical hyperventilation.

Saline-filled laparoscopic surgery: A basic study on partial hepatectomy in a rabbit model

BACKGROUND

There is still a poor understanding of the effects of pneumoperitoneum with insufflation of carbon dioxide gas (CO2) on malignant cells, and pneumoperitoneum has a negative impact on cardiopulmonary responses. A novel saline-filled laparoscopic surgery (SAFLS) is proposed, and the technical feasibility of performing saline-filled laparoscopic partial hepatectomy (LPH) was evaluated in a rabbit model.

MATERIAL AND METHODS

Twelve LPH were performed in rabbits, with six procedures performed using an ultrasonic device with CO2 pneumoperitoneum (CO2 group) and six procedures performed using a bipolar resectoscope (RS) in a saline-filled environment (saline group). Resection time, CO2 and saline consumption, vital signs, blood gas analysis, complications, interleukin-1 beta (IL-1β) and C-reactive protein (CRP) levels were measured. The effectiveness of the resections was evaluated by the pathological findings.

RESULTS

LPH was successfully performed with clear observation by irrigation and good control of bleeding by coagulation with RS. There were no significant differences in all perioperative values, IL-1βand CRP levels between the two groups. All pathological specimens of the saline group showed that the resected lesions were coagulated and regenerated as well as in the CO2 group.

CONCLUSIONS

SAFLS is feasible and provides a good surgical view with irrigation and identification of bleeding sites.

Effect of carbon dioxide pneumoperitoneum on human renal cell carcinoma proliferation and metastasis in an orthotropic xenograft nude mouse model

INTRODUCTION

This study aimed to explore the effect of carbon dioxide (CO2) pneumoperitoneum on tumor proliferation and metastasis in an orthotropic xenograft nude mice model of human renal cell carcinoma (RCC) and evaluate the safety of CO2 pneumoperitoneum laparoscopy for treating RCC.

MATERIAL AND METHODS

RCC 786-0 cells were injected to establish an orthotropic xenograft model. Fifty nude mice were given orthotropic inoculations and randomized to five groups: group A (control); group B (CO2 pneumoperitoneum for 2 h); group C (CO2 pneumoperitoneum for 4 h); group D (CO2 pneumoperitoneum for 4 h and 24 h after waking); group E (CO2 pneumoperitoneum for 4 h and 48 h after waking). The proliferation status was observed in RCC specimens by immunohistochemical staining for Ki67. The protein levels of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) were examined by western blotting.

RESULTS

All groups showed similar Ki67-positive staining in RCC samples (p > 0.05). The relative expression of HIF-1α and VEGF gradually increased in both group B and group C, as compared with group A, but only the difference between group C and group A reached statistical significance (p < 0.05). The protein levels of HIF-1α and VEGF decreased in both group D and group E, as compared with group B and group C; however, the differences between group D, group E, and group A did not reach statistical significance (p > 0.05).

CONCLUSIONS

In an orthotropic xenograft nude mice model of RCC, CO2 pneumoperitoneum has no effect on expression of the cellular proliferation marker Ki67. However, CO2 pneumoperitoneum rapidly induces transient expression of HIF-1α and VEGF. Thus, CO2 pneumoperitoneum laparoscopy may be a safe method for treating RCC.

Respiratory syncytial virus persistence in macrophages downregulates intercellular adhesion molecule-1 expression and reduces adhesion of non-typeable Haemophilus influenzae

BACKGROUND

Persistence of respiratory syncytial virus (RSV) has been associated with episodes of chronic obstructive pulmonary disease (COPD); furthermore, co-infection of RSV with non-typeable Haemophilus influenzae (NTHi) is increasingly recognized as a cause of exacerbations of COPD.

OBJECTIVE

To study whether RSV persistence in a macrophage (Mφ)-like cell line alters NTHi uptake (adhesion and ingestion).

METHODS

A murine Mφ-like cell line persistently infected with RSV (MφP) was used. The effects of RSV persistence on NTHi uptake by MφP and mock-infected Mφ (MφN) were determined by flow-cytometric assays with NTHi labelled with either ethidium bromide or FITC. Expression of intercellular adhesion molecule-1 (ICAM-1), a ligand for NTHi, was determined by measuring mRNA through real-time PCR and protein by Western blot assays.

RESULTS

RSV persistence reduced both the capacity of Mφ to take up bacteria and the expression of ICAM-1 mRNA and protein. Furthermore, when ICAM-1 was blocked with anti-ICAM-1 antibody, the adhesion capacity of NTHi was significantly reduced for MφN, whereas for MφP the effect was less evident, implying that ICAM-1 participates in NTHi adhesion to Mφ.

CONCLUSION

RSV persistence in murine Mφ diminishes their capacity to adhere and ingest NTHi through downregulation of ICAM-1 expression at the transcriptional level.

Tumor interstitial fluid and gastric cancer metastasis: an experimental study to verify the hypothesis of "tumor-phlegm microenvironment"

OBJECTIVE

To extract tumor interstitial fluid (TIF) from MKN-45 gastric cancer which is similar to "muddy phlegm" in Chinese medicine and observe influences of MKN-45 tumor interstitial fluid (MKN-45 TIF) intervention on metastasis of gastric cancer and on the expressions of vascular endothelial growth factor (VEGF), kinase insert domain containing receptor (KDR), epithelial-cadherin (E-cad), cyclooxygenase-2 (COX-2), intercellular adhesion molecule-1 (ICAM-1) and telomerase genes and proteins in primary tumor tissue.

METHODS

An MKN-45 tumor-bearing model was established in 50 nude mice. The modeled animals were equally randomized to 5 groups: the simple tumor-bearing group (model group), the normal saline (NS) via tail vein injection (i.v.) group (NS i.v. group), MKN-45 TIF i.v. group (TIF i.v. group), NS intraperitoneal injection (i.p.) group (NS i.p. group), and MKN-45 TIF i.p. group (TIF i.p. group). The TIF and NS intervention groups received injection (i.p. or i.v.) of MKN-45 TIF or NS twice a week, 0.2 mL at a time. After 8 weeks, the primary tumors were removed, weighed and HE stained to observe tumor metastasis. The primary tumor tissues were analyzed by immunohistochemistry and real-time quantitative PCR to detect expressions of VEGF, KDR, E-cad, COX-2, ICAM-1, and telomerase genes and proteins in different groups.

RESULTS

There were significant differences in tumor weight between TIF intervention groups and the model and NS intervention groups. Tumor metastasis was observed in all 5 groups, but the tumor metastasis rate in TIF intervention groups was significantly higher than those in the model and NS intervention groups. The gene and protein expressions of gastric cancer-related factors VEGF, KDR, COX-2, ICAM-1 and telomerase were unregulated while the gene and protein expressions of E-cad were downregulated in TIF intervention groups.

CONCLUSIONS

TIF promotes tumor growth, invasion and metastasis of gastric cancer. These findings provide preliminary experimental clues for verifying the hypothesis of "tumor-phlegm microenvironment".