Effects of TVE application during 70% hepatectomy on regeneration capacity of rats1

Efficacy and safety of hepatectomy performed with intermittent portal triad clamping with low central venous pressure

Background. This retrospective study was designed to investigate the efficacy and safety of intermittent portal triad clamping (PTC) with low central venous pressure (CVP) in liver resections. Methods. Between January 2007 and August 2013, 115 patients underwent liver resection with intermittent PTC. The patients' data were retrospectively analyzed. Results. There were 58 males and 57 females with a mean age of 55 years (±13.7). Cirrhosis was found in 23 patients. Resections were performed for malignant disease in 62.6% (n = 72) and for benign disease in 37.4% (n = 43). Major hepatectomy was performed in 26 patients (22.4%). Mean liver ischemia period was 27.1 min (±13.9). The mortality rate was 1.7% and the morbidity rate was 22.6%. Cumulative clamping time (t = 3.61, P < 0.001) and operation time (t = 2.38, P < 0.019) were significantly correlated with AST alterations (D-AST). Cumulative clamping time (t = 5.16, P < 0.001) was significantly correlated with D-ALT. Operation time (t = 5.81, P < 0.001) was significantly correlated with D-LDH. Conclusions. Intermittent PTC under low CVP was performed with low morbidity and mortality. Intermittent PTC can be safely applied up to 60 minutes in both normal and impaired livers.

Hepatic microcirculation in inflow and inflow-outflow occlusion of the liver

BACKGROUND

Total vascular exclusion (TVE) causes warm liver ischemia. The aim of this study was to investigate the patterns of injury caused by inflow-outflow obstruction in the rat liver.

MATERIALS AND METHODS

Twenty-four Wistar-Albino rats were divided into three groups: liver inflow occlusion (Group A), inflow-outflow occlusion (Group B) and intermittent inflow-outflow occlusion applied for 15 minutes. Microcirculation was measured with laser Doppler flowmetry during the procedure. Samples for biochemical and histopathological analyses were collected at the end of the ischemia period.

RESULTS

Significant alterations in microcirculation were determined by application of vascular control maneuvers. Microcirculation in the central and dome segments were affected adversely compared with the dome segments in all experimental groups. TVE induced severe disturbances in hepatic microcirculation with more prominent hepatocellular damage. Damage to central segments of the rat liver was more prominent with inflow occlusion; whereas inflow-outflow occlusion produced more prominent damage to dome segments. Intermittent application of TVE clamping was associated with more hepatocellular damage compared with continuous TVE.

CONCLUSION

Our mapping methodology within the liver parenchyma suggested that hepatovenous back-perfusion is a principle source of continuity of microcirculation in the rat liver during inflow occlusion. Inflow-outflow occlusion caused more tissue damage compared with inflow occlusion. Ischemic preconditioning during TVE did not increase the tolerance of the liver against ischemia.

Evaluation of the effects of a VEGFR-2 inhibitor compound on alanine aminotransferase gene expression and enzymatic activity in the rat liver

BACKGROUND

Traditional assessment of drug-induced hepatotoxicity includes morphological examination of the liver and evaluation of liver enzyme activity in serum. The objective of the study was to determine the origin of drug-related elevation in serum alanine aminotransferase (ALT) activity in the absence of morphologic changes in the liver by utilizing molecular and immunohistochemical techniques.

METHODS

Sixteen female Sprague-Dawley rats were divided into 2 groups (control and treated, n = 4 per group) and treated rats were dosed orally twice daily (400 mg/kg/day) for 7 days with a VEGFR-2 compound (AG28262), which in a previous study caused ALT elevation without morphological changes. Serum of both treated and control animals were evaluated on day 3 of treatment and at day 8. Three separate liver lobes (caudate, right medial, and left lateral) were examined for determination of ALT tissue activity, ALT gene expression and morphological changes.

RESULTS

ALT activity was significantly (p < 0.01) elevated on day 3 and further increased on day 8. Histologic changes or increase in TUNEL and caspase3 positive cells were not observed in the liver lobes examined. ALT gene expression in the caudate lobe was significantly up-regulated by 63%. ALT expression in the left lateral lobe was not significantly affected. Statistically significant increased liver ALT enzymatic activity occurred in the caudate (96%) and right medial (41%) lobes but not in the left lateral lobe.

CONCLUSIONS

AG28262, a VEFG-r2 inhibitor, causes an increase in serum ALT, due in part to both gene up-regulation. Differences between liver lobes may be attributable to differential distribution of blood from portal circulation. Incorporation of molecular data, such as gene and protein expression, and sampling multiple liver lobes may shed mechanistic insight to the evaluation of hepatotoxicity.

Non-toxicity of IV injected perfluorocarbon oxygen carrier in an animal model of liver regeneration following surgical injury

Lethal dose experiments in animals have demonstrated that second-generation perfluorocarbon oxygen carriers are remarkably non-toxic. However, this non-toxicity has not previously been demonstrated in a liver failure scenario. A surgical liver damage and regeneration model in rats was selected using a well-controlled cross tabulated study design. A large number of physiological, biochemical, and hematological parameters were measured. No indications were found that intravenously injected perfluorooctyl bromide emulsion was toxic at the concentrations employed, in either healthy or severe liver injury scenarios. Neither was there any significant impact on the rate of liver regeneration following the injuries. Bearing in mind prior human clinical studies, it is therefore safe to assume that perfluorocarbon emulsions are also non-toxic in bioartificial liver treatments.

Heterogeneity of Damage Between Segments of Rat Liver After Inflow-Outflow Obstruction

BACKGROUND

Total vascular exclusion (TVE) causes warm liver ischemia. The complete explanation of the events during inflow and outflow obstruction of the liver during selective TVE has not yet been studied. The aim of this study was to investigate the liver injury caused by inflow-outflow obstruction in the rat liver.

MATERIALS AND METHODS

Forty Wistar-Albino rats were divided into four groups. Liver inflow occlusion (groups A and C) or inflow-outflow occlusion (groups B and D) was applied for 30 minutes. Samples were collected at the end of the ischemia period. We examined oxidative injury in the liver tissue and liver histopathology.

RESULTS

Oxidative stress and histopathologic alterations were more prominent with TVE application. Significant alterations were shown in hepatic superoxide dismutase, glutathione, and glutathione S-transferase levels. Central segments of the rat liver were affected significantly from inflow occlusion, whereas dome segments were significantly damaged from inflow-outflow occlusion.

CONCLUSIONS

Inflow-outflow occlusion of the liver caused more tissue damage compared with inflow occlusion. The pattern of distribution of the damage due to TVE seemed different from other well-known ischemia-reperfusion injuries.

Evaluation of Liver Damage After Application of TVE in the Rat Model

INTRODUCTION

The aim of this study was to investigate the effects of total vascular exclusion (TVE) on the liver during the early period of reperfusion.

MATERIALS AND METHODS

Forty Wistar-Albino rats were divided into four groups. Portal pedicle clamping (groups 1 and 2) or TVE (groups 3 and 4) were applied for 10 minutes. Samples were collected at the time of clamp release (groups 1 and 3) and at 30 minutes of reperfusion (groups 2 and 4). We examined oxidative injury to and histopathology of the liver.

RESULTS

Oxidative stress was more prominent with TVE application. Significant alterations were shown in hepatic superoxide dismutase, catalase, glutathione, and glutathione S-transferase levels. The levels of malondialdehyde and myeloperoxidase were not altered significantly.

CONCLUSION

Inflow-outflow occlusion of the liver causes more oxidative stress compared with inflow occlusion.