Intermittent hepatic pedicle clamping reduces liver and lung injury

Pentoxifylline enhances the protective effects of hypertonic saline solution on liver ischemia reperfusion injury through inhibition of oxidative stress

BACKGROUND

Liver ischemia reperfusion (IR) injury triggers a systemic inflammatory response and is the main cause of organ dysfunction and adverse postoperative outcomes after liver surgery. Pentoxifylline (PTX) and hypertonic saline solution (HTS) have been identified to have beneficial effects against IR injury. This study aimed to investigate if the addition of PTX to HTS is superior to HTS alone for the prevention of liver IR injury.

METHODS

Male Wistar rats were allocated into three groups. Control rats underwent 60 minutes of partial liver ischemia, HTS rats were treated with 0.4 mL/kg of intravenous 7.5% NaCl 15 minutes before reperfusion, and HPTX group were treated with 7.5% NaCl plus 25 mg/kg of PTX 15 minutes before reperfusion. Samples were collected after reperfusion for determination of ALT, AST, TNF-alpha, IL-6, IL-10, mitochondrial respiration, lipid peroxidation, pulmonary permeability and myeloperoxidase.

RESULTS

HPTX significantly decreased TNF-alpha 30 minutes after reperfusion. HPTX and HTS significantly decreased ALT, AST, IL-6, mitochondrial dysfunction and pulmonary myeloperoxidase 4 hours after reperfusion. Compared with HTS only, HPTX significantly decreased hepatic oxidative stress 4 hours after reperfusion and pulmonary permeability 4 and 12 hours after reperfusion.

CONCLUSION

This study showed that PTX added the beneficial effects of HTS on liver IR injury through decreases of hepatic oxidative stress and pulmonary permeability.

Increased E-selectin in hepatic ischemia-reperfusion injury mediates liver metastasis of pancreatic cancer

Several recent studies have reported that selectins are produced during ischemia-reperfusion injury, and that selectin ligands play an important role in cell binding to the endothelium and in liver metastasis. Portal clamping during pancreaticoduodenectomy with vessel resection for pancreatic head cancer causes hepatic ischemia-reperfusion injury, which might promote liver metastasis. We investigated the liver colonization of pancreatic cancer cells under hepatic ischemia-reperfusion and examined the involvement of E-selectin and its ligands. A human pancreatic cancer cell line (Capan-1) was injected into the spleen of mice after hepatic ischemia-reperfusion (I/R group). In addition, to investigate the effect of an anti-E-selectin antibody on liver colonization in the IR group, mice received an intraperitoneal injection of the anti-E-selectin antibody following hepatic ischemia-reperfusion and tumor inoculation (IR+Ab group). Four weeks later, mice were sacrificed and the number of tumor nodules on the liver was compared to mice without hepatic ischemia-reperfusion (control group). The incidence of liver metastasis in the I/R group was significantly higher (16 of 20, 80%) than that in the control group (6 of 20, 30%) (P<0.01). Moreover, mice in the I/R group had significantly more tumor nodules compared to those in the control group (median, 9.9 vs. 2.7 nodules) (P<0.01). In the I/R+Ab group, only 2 of 5 (40%) mice developed liver metastases. RT-PCR and southern blotting of the liver extracts showed that the expression of IL-1 and E-selectin mRNA after hepatic ischemia-reperfusion was significantly higher than the basal levels. Hepatic ischemia-reperfusion increases liver metastases and E-selectin expression in pancreatic cancer. These results suggest that E-selectin produced due to hepatic ischemia-reperfusion is involved in liver metastasis.

Ischaemic Preconditioning and Intermittent Clamping Does not Influence Mediators of Liver Regeneration in a Human Liver Sinusoidal Endothelial Cell Model of Ischaemia-Reperfusion Injury

BACKGROUND

The role of surgical technique on liver regeneration following surgery remains inconclusive. The aim of the study was to assess the effect of ischaemic preconditioning (IPC) and intermittent clamping (IC) on mediators of regeneration produced by human liver sinusoidal endothelial cells (SECs), using an in vitro hypoxia-reoxygenation model to mimic ischaemia-reperfusion injury (IRI).

METHODS

Following extraction from samples obtained from liver resection (n = 5), confluent culture flasks of SECs were subjected to IRI (1 hour hypoxia + 1 hour reoxygenation), IPC prior to IRI (10 minutes hypoxia + 10 minutes reoxygenation + 1 hour hypoxia + 1 hour reoxygenation), IC (15 minutes hypoxia + 5 minutes reoxygenation x 3 + 1 hour reoxygenation) and compared to controls. The production of various mediators was determined over 48 hours.

RESULTS

Interleukin (IL)-6, IL-8, granulocyte-colony stimulating factor (G-CSF) and hepatocyte growth factor (HGF) were produced by SECs. Both IPC and IC did not significantly influence the profile of IL-6, IL-8, G-CSF and HGF by SECs compared to IRI over the study period.

CONCLUSION

IPC and IC did not influence the production of pro-regenerative mediators in a SECs model of IRI. The role of surgical technique on liver regeneration remains to be determined.

Colorectal liver metastasis surgery: analysis of risk factors predicting postoperative complications in relation to the extent of resection

BACKGROUND/AIMS

Despite advances in diagnosis and treatment, the rate of complications after resection for colorectal liver metastases remains high. An awareness of risk factors is essential for the rates of morbidity and mortality to fall to optimal levels.

MATERIALS AND METHODS

Of the 240 patients who underwent resection for the first manifestation of colorectal liver metastases, 49 patients with lobectomy or extended hepatectomy (major resections) and 58 with wedge resections within only one liver segment (minor resections) form the basis of this report. A total of 16 variables were analyzed to find the risk factors linked to postoperative morbidity and mortality.

RESULTS/FINDINGS

Thirty-four patients (31.8%) suffered postoperative complications, and one patient died during the hospital stay (0.9%). In the major resection group, multivariate analysis showed that neoadjuvant chemotherapy [odds ratio (OR): 2.4; p = 0.005], vascular clamping (OR: 1.4; p = 0.008), and intraoperative blood loss with transfusion of three to six packed red cell units (OR: 1.2; p = 0.029) were significantly associated with postoperative morbidity. Vascular clamping was an independent predictor for biliary fistula (OR: 1.2; p = 0.029). Postoperative temporary liver failure was influenced by neoadjuvant chemotherapy (OR: 3.4; p = 0.010), vascular clamping (OR: 1.5; p = 0.015), and requirement of blood transfusion (OR: 2.1; p = 0.016). After minor resections, only a decreased postoperative serum cholinesterase B level was an independent predictor for complications (OR: 2.2; p = 0.001), as well as for hemorrhage (OR: 1.6; p = 0.023). Postoperative mortality was not predicted by any of the factors that were analyzed.

INTERPRETATION/CONCLUSION

Factors for complications differ depending on the extent of colorectal liver metastasis resection. Only knowledge and particular consideration of these factors may provide for an optimal postoperative outcome for the individual patient.

The Pringle manoeuvre should be avoided in hepatectomy for cancer patients due to its side effects on tumor recurrence and worse prognosis

Curative hepatectomy is still the best therapeutic strategy for liver cancer treatment up to now. The Pringle manoeuvre has been commonly used to avoid massive blood loss during operation since its advent, which greatly accelerates the advance of liver surgery and oncological surgery. In the past century, more attentions have been paid to different effects of ischemia-reperfusion injury elicited by Pringle manoeuvre. Theses include its impacts on complex metabolic, immunological, and microvascular changes, which altogether might contribute to hepatocellular damage and dysfunction, and contribute to haemodynamic instability. Despite these adverse impacts, the short-term outcome of affected patients under hepatectomy was greatly improved with the advances of surgical techniques and perioperative management in recent years. While the long-term prognosis remains unsatisfactory due to a high incidence of intra/extrahepatic recurrence. The reason for it was not totally elucidated. Furthermore, the effect of the Pringle manoeuvre on the prognosis of oncologic patients and behavior of the tumor cell was not deliberately mentioned. This point was put forward to the front-desk by the specific phenomenon from recent animal studies. It is showed that ischemia-reperfusion injury of the liver remnant may be a significant factor to promote the tumor recurrence and metastasis. If it is a truth in human, there must be a big challenge to the Pringle manoeuvre. So we hypothesized that the long-term prognosis of cancer patients could be worsened by the ischemia-reperfusion injury elicited by Pringle manoeuvre during the hepatectomy and it should be revised, or even, avoided in future hepatectomy for oncologic patients. The less surgical stress including ischemia-reperfusion injury in the hepatic resection without Pringle manoeuvre might contribute to a better prognosis. To get a deeper understanding, prospective randomized clinical trials need to be done. It is surely supposed to provide more important information about the long-term effects of the Pringle manoeuvre, and to our hypothesis.

Short-term effects of N-acetylcysteine and ischemic preconditioning in a canine model of hepatic ischemia-reperfusion injury

AIMS

We evaluated the possibility that repeated ischemic preconditioning or N-acetylcysteine (NAC) could prevent ischemia-reperfusion injury as determined by indocyanine green plasma disappearance rate (ICG-PDR) or has favorable hemodynamic effects during reperfusion in an in vivo canine liver model.

METHODS

Under general anesthesia, 3 groups of mongrel dogs (n = 5 per group) were subjected to (1) 60-min hepatic ischemia, (2) same ischemia preceded by intravenous administration of 150 mg kg(-1) NAC, and (3) three episodes of IPC (10-min ischemia followed by 10-min reperfusion) prior to same ischemia. Hepatic reperfusion was maintained for a further 180 min, with hemodynamic and hepatic function parameters monitored throughout.

RESULTS

Plasma disappearance rate of indocyanine green and serum levels of aspartate transferase and alanine transferase showed no significant differences between groups. Although liver injury was obvious, reflected by hemodynamic, blood gas, and liver function tests, NAC and IPC failed to prevent decay in hepatic function in this canine model.

CONCLUSION

The results do not support the hypothesis that short-term use of NAC and IPC is beneficial in hepatic surgery.

Alterations in the proteome of pulmonary alveolar type II cells in the rat after hepatic ischemia-reperfusion

OBJECTIVE

Hepatic ischemia-reperfusion can be associated with acute lung injury. Alveolar epithelial type II cells (ATII) play an important role in maintaining lung homeostasis in acute lung injury.

DESIGN

To study potentially new mechanisms of hepatic ischemia-reperfusion-induced lung injury, we examined how liver ischemia-reperfusion altered the proteome of ATII.

SETTING

Laboratory investigation.

SUBJECTS

Spontaneously breathing male Zucker rats.

INTERVENTIONS

Rats were anesthetized with isoflurane. The vascular supply to the left and medial lobe of the liver was clamped for 75 mins and then reperfused. Sham-operated rats were used as controls. After 8 hrs, rats were killed.

MEASUREMENTS AND MAIN RESULTS

Bronchoalveolar lavage and differential cell counts were performed, and tumor necrosis factor-alpha and cytokine-induced neutrophil chemotactic factor-1 in plasma were determined by enzyme-linked immunosorbent assay. ATII were isolated, lysed, tryptically digested, and labeled using isobaric tags (iTRAQ). The samples were fractionated by cation exchange chromatography, separated by high-performance liquid-chromatography, and identified using electrospray tandem mass spectrometry. Spectra were interrogated and quantified using ProteinProspector. Quantitative proteomics provided quantitative data for 94 and 97 proteins in the two groups. Significant changes in ATII protein content included 30% to 40% increases in adenosine triphosphate synthases, adenosine triphosphate/adenosine diphosphate translocase, and catalase (all p < .001). Following liver ischemia-reperfusion, there was also a significant increase in the percentage of neutrophils in bronchoalveolar lavage (48% +/- 26%) compared with sham-operated controls (5% +/- 3%) (p < .01), and plasma tumor necrosis factor-alpha levels were also significantly increased.

CONCLUSIONS

The proteins identified by quantitative proteomics indicated significant changes in moderators of cell metabolism and host defense in ATII. These findings provide new insights into possible mechanisms responsible for hepatic ischemia-reperfusion-related acute lung injury and suggest that ATII cells in the lung sense and respond to hepatic injury.

Protective effect of Sivelestat in a porcine hepatectomy model prepared using an intermittent Pringle method

The effect of Sivelestat, a neutrophil elastase inhibitor, on hepatic ischemia-reperfusion injury was examined in a pig hepatectomy model. An internal jugular vein-splenic vein bypass was prepared in male pigs and about 40% hepatic resection (left lobe) was performed under 15-min liver ischemia and 5-min intermittent reperfusion. Six animals received Sivelestat (10 mg/kg/h) intravenously and six control animals received physiological saline (10 mg/kg/h) from commencement of laparotomy. Hemodynamics, blood chemistry, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), lactic acid, hyaluronic acid, nitrite/nitrate (NOS), and tumor necrosis factor-alpha (TNF-alpha) were compared between the groups. The effects of Sivelestat on NOS generation and expression of iNOS mRNA and TNF-alpha mRNA were also assessed in J774 cells. Expression of TNF-alpha mRNA in hepatic tissues was examined using RT-PCR. The blood pressure of control animals was significantly lower immediately and 3 h after ischemia-reperfusion, compared with that at commencement of laparotomy, whereas there was no decrease of blood pressure in animals administered Sivelestat. Serum AST (P=0.0045), NOS (P=0.0098), and TNF-alpha (P=0.041) levels were significantly lower 3 h after hepatectomy in animals receiving Sivelestat. Sivelestat inhibited NOS production in J774 cells, but did not inhibit expression of iNOS mRNA or TNF-alpha mRNA. In hepatic tissues, Sivelestat showed a greater tendency to inhibit expression of TNF-alpha mRNA and fewer TUNEL-positive cells were present in the hepatic sinusoidal endothelium after Sivelestat treatment, although these differences were not statistically significant. We conclude that Sivelestat inhibits production of TNF-alpha and NO by inhibiting neutrophil elastase, and thus reduces hepatic injury and stabilizes hemodynamics after ischemia-reperfusion.

Hepatic ischemia-reperfusion increases vascular endothelial growth factor and cancer growth in rats

BACKGROUND

In liver surgery, the hepatic pedicle often is clamped to reduce blood loss, and later unclamped, representing hepatic ischemia and reperfusion (I/R) with induction of hypoxia. Vascular endothelial growth factor (VEGF) expression reportedly is induced by hypoxia; further, some cancer cells express the VEGF receptor (flt-1, flk-1/KDR). We hypothesized that I/R-induced VEGF expression could enhance growth of microscopic tumor via VEGF receptors on tumor cells, thus promoting liver metastasis in a rat model.

MATERIALS AND METHODS

Time-dependent VEGF expression in liver and plasma was determined by enzyme-linked immunosorbent assay in rats subjected to 60 min of 70% hepatic I/R (I/R group). Other rats given an intrasplenic inoculation of a rat colon adenocarcinoma cell line (RCH-H4) were divided 3 days later into three groups: group A, untreated; group B, sham operation; group C, 70% I/R for 60 min. Liver metastasis was evaluated on day 14. Expression of flt-1 and flk-1/KDR was examined in RCN-H4 cells, and effects of exogenous VEGF on RCN-H4 cell proliferation were determined by MTT assays.

RESULTS

Hepatic VEGF expression increased significantly in the I/R group compared to the control group. Liver metastasis was more extensive in group C than in groups A and B. RCN-H4 cells expressed flt-1 and flk-1/KDR, while exogenous VEGF increased RCN-H4 cell proliferation.

CONCLUSION

Hepatic ischemia reperfusion leads to induction of VEGF and this is associated with increased tumor burden in an animal model of colon cancer metastasis.

Protective Effect of Ischemic Preconditioning against Liver Injury after Major Hepatectomy Using the Intermittent Pringle Maneuver in Swine

OBJECTIVE

To investigate whether ischemic preconditioning (IP) protects the liver against ischemia-reperfusion injury (I/R-I) after major hepatectomy through intermittent hepatic pedicle clamping (IC) in a swine liver resection model.

BACKGROUND

Although many studies have reported a protective effect of IP against continuous hepatic ischemia, it has not been elucidated whether IP protects the liver against I/R-I after hepatectomy using IC. This is the first study to evaluate the effect of IP in a swine major hepatectomy model using IC.

METHODS

Pigs (n = 12) were divided into 2 groups (IP or non-IP). In the IP group, livers were subjected to IP (10 min ischemia and 10 min reperfusion) before liver resection using IC (15 min ischemia and 5 min reperfusion). A left hemihepatectomy was then performed using IC in both groups. Hemodynamic changes and plasma concentrations of aspartate aminotransferase, lactate dehydrogenase, lactic acid and hyaluronic acid were measured at 60, 120 and 180 min after hepatectomy. Apoptosis (TUNEL staining and electron microscopy), plasma tumor necrosis factor-alpha (TNF-alpha) and NO(2)(-)/NO(3)(-) were evaluated for 180 min after hepatectomy.

RESULTS

There were no significant differences in body weight, blood loss, resected liver weight, Pringle time or hemodynamic changes between the 2 groups. IP significantly reduced plasma aspartate aminotransferase levels for 180 min after hepatectomy (IP: 135.8 +/- 13.5 vs. non-IP: 199 +/- 16.8 IU/l; p = 0.018). In the non-IP group, apoptotic changes in sinusoidal endothelial cells were observed with increased plasma TNF-alpha levels. IP protected liver injury from increase in plasma TNF-alpha (p = 0.042). Significantly fewer apoptotic cells were seen in the IP than in the non-IP group (p = 0.002). Plasma levels of lactate dehydrogenase, lactic acid and NO(2)(-)/NO(3)(-) in the IP group tended to be lower than those in the non-IP group.

CONCLUSIONS

IP prior to hepatectomy with IC resulted in less hepatic injury and apoptotic cell death than in livers not subjected to IP. IP with IC has the potential to improve the clinical postoperative course of patients undergoing hepatectomy.

Methimazole protects lungs during hepatic ischemia-reperfusion injury in rats: an effect not induced by hypothyroidism

BACKGROUND

Hepatic ischemia-reperfusion injury may lead to remote organ failure with mortal respiratory dysfunction. The aim of the present study was to analyze the possible protective effects of methimazole on lungs after hepatic ischemia-reperfusion injury.

METHODS

Forty male Wistar albino rats were randomized into five groups: a control group, in which bilateral pulmonary lobectomy was done; a hepatic ischemia-reperfusion group, in which bilateral pulmonary lobectomy was done after hepatic ischemia-reperfusion; a thyroidectomy-ischemia-reperfusion group (total thyroidectomy followed by, 7 days later, bilateral pulmonary lobectomy after hepatic ischemia-reperfusion); a methimazole-ischemia-reperfusion group (following methimazole administration for 7 days, bilateral pulmonary lobectomy was done after hepatic ischemia-reperfusion); and a methimazole +L-thyroxine-ischemia-reperfusion group (following methimazole and L-thyroxine administration for 7 days, bilateral pulmonary lobectomy was performed after hepatic ischemia-reperfusion). Pulmonary tissue specimens were evaluated histopathologically and for myeloperoxidase and malondialdehyde levels.

RESULTS

All of the ischemia-reperfusion intervention groups had higher pulmonary injury scoring indices than the control group (P < 0.001). Pulmonary injury index of the ischemia-reperfusion group was higher than that of both the methimazole-supplemented hypothyroid and euthyroid groups (P = 0028; P = 0,038, respectively) and was similar to that of the thyroidectomized group. Pulmonary tissue myeloperoxidase and malondialdehyde levels in the ischemia-reperfusion group were similar with that in the thyroidectomized rats but were significantly higher than that in the control, and both the methimazole-supplemented hypothyroid and euthyroid groups.

CONCLUSION

Methimazole exerts a protective role on lungs during hepatic ischemia-reperfusion injury, which can be attributed to its anti-inflammatory and anti-oxidant effects rather than hypothyroidism alone.

Warm hepatic ischemia-reperfusion promotes growth of colorectal carcinoma micrometastases in mouse liver via matrix metalloproteinase-9 induction

Surgical resection remains the best treatment for colorectal metastases isolated to the liver; however, 5-year survival rates following liver resection are only 40% to 50%, with liver recurrence being a significant reason for treatment failure. The ischemia-reperfusion (I/R) injury incurred during liver surgery can lead to cellular dysfunction and elevations in proinflammatory cytokines and matrix metalloproteinases (MMP). In rodents, I/R injury to the liver has been shown to accelerate the outgrowth of implanted tumors. The mechanism for increased tumor growth in the setting of liver I/R injury is unknown. To investigate the effect of I/R on tumor growth, an experimental model was used whereby small hepatic metastases form after 28 days. Mice subjected to 30 min of 70% liver ischemia at the time of tumor inoculation had significantly larger tumor number and volume, and had elevated MMP9 serum and liver tissue MMP9 as evidenced by zymography and quantitative real-time PCR. Mice treated with doxycycline, a broad-spectrum MMP inhibitor, had reduced MMP9 levels and significantly smaller tumor number and volume in the liver. MMP9-null mice were used to determine if the effects of doxycycline were due to the absence of stromal-derived MMP9. The MMP9-null mice, with or without doxycycline treatment, had reduced tumor number and volume that was equivalent to wild-type mice treated with doxycycline. These findings indicate that hepatic I/R-induced elevations in MMP9 contribute to the growth of metastatic colorectal carcinoma in the liver and that postresection MMP9 inhibition may be clinically beneficial in preventing recurrence following hepatic surgery.

Consistent liver metastases in a rat model by portal injection of microencapsulated cancer cells

Consistent liver metastases in animal models is generally observed only with certain cancer cell lines. With the aim of improving on existing animal models of liver metastases, we hypothesized that cancer cells encased in 300 microm microcapsules, mimicking micrometastatic foci, might be effective seeds of liver metastases. A total of 3,000 microcapsules, containing 700 to 1,500 viable cells/capsule in logarithmic growth phase of three human pancreatic cancer cell lines (SUIT-2, AsPC-1, and BxPC-3), were transplanted in nude rats by portal injection. The rate of liver metastases was 100% (12 of 12), 100% (6 of 6), and 83% (5 of 6) for SUIT-2, AsPC-1, and BxPC-3 microcapsules, respectively. In contrast, the administration of an identical number of single cancer cells (2.1-4.5 x 10(6)) did not lead to liver metastases. Metastases was strictly limited to the liver, was quite stable, and could be proportionately tailored by varying the number of cancer microcapsules administered. Microscopic observation showed that two-thirds of the cancer microcapsules were lodged in the peripheral small (20-50 microm) portal veins, although one-third of the cancer microcapsules were trapped in the central wide (200-400 microm) portal vein. Capsules began to burst at day 3, with recognizable metastases produced at day 7, resulting in overt metastases production at days 28 to 42. The present cancer microcapsule method may be useful for obtaining liver metastases in animal models, especially for cell lines that will not form liver metastases with conventional single cell injection methods and/or for experiments requiring the consistent formation of liver metastases.

Avaliação bioquímica dos efeitos do pré-condicionamento isquêmico após isquemia e reperfusão hepática em ratos

OBJETIVO: Comparar a lesão hepatocelular ocasionada pelo emprego do pré-condicionamento isquêmico e de duas outras modalidades de clampeamento tríade portal: clampeamento contínuo e intermitente. MÉTODO: Quarenta ratos Wistar foram divididos em quatro grupos de 10 animais cada. No Grupo Sham nenhuma espécie de clampeamento foi adotada. Nos outros três, provocamos isquemia de quarenta minutos por meio do clampeamento do pedículo hepático. No Grupo I esta isquemia foi contínua. No Grupo II, também contínua, mas precedida de cinco minutos de isquemia e 10 minutos de reperfusão (précondicionamento isquêmico). No Grupo III foi realizada isquemia intermitente em ciclos de 10 min de isquemia e cinco minutos de reperfusão. Para avaliar a lesão hepatocelular foi adotada a dosagem de transaminase glutâmico oxalacética (TGO), glutâmico pirúvica (TGP) e lactato desidrogenase (LDH), aferidas no início e no final dos procedimentos. RESULTADOS: Não houve diferença estatística nos valores basais das enzimas estudadas, demonstrando uniformidade nos grupos. Os quatro grupos apresentaram variação significativa de todas as enzimas entre os dois momentos de coleta, porém de forma diferenciada. A variação no Grupo Sham foi menor que a do grupo II. Este foi semelhante ao grupo III e em todos a elevação foi significativamente menor que no grupo I (D do Sham CONCLUSÕES: Em ratos Wistar o clampeamento contínuo do pedículo hepático, precedido de um ciclo de cinco minutos de isquemia e 10 minutos de reperfusão (pré-condicionamento isquêmico) provoca menor lesão hepática do que o clampeamento contínuo e apresenta resultados comparáveis aos obtidos através da utilização do clampeamento intermitente, em fígados normais submetidos a um período de isquemia hepática de 40 minutos e um tempo total de cirurgia de 60 minutos.

Edaravone reduces ischemia-reperfusion injury mediators in rat liver

BACKGROUND

In hepatic ischemia-reperfusion (I/R) injury, oxidative stress both directly injures the liver and promotes an inflammatory reaction by up-regulating various inflammatory mediators. We investigated whether edaravone, a new hydroxy radical scavenger, could reduce hepatic I/R injury including expression of inflammatory mediators such as cytokines and adhesion molecules.

MATERIALS AND METHODS

Male Sprague-Dawley rats were subjected to 30 min of partial hepatic pedicle clamping (70%) followed by reperfusion. Just after initiation of reperfusion and again 1 h later, edaravone was administered intraportally. After reperfusion hepatic lipid peroxidation was measured by thiobarbituric acid assay, and hepatic injury was quantified by measuring hepatic enzymes in plasma. We serially quantified hepatic expression of mRNAs for tumor necrosis factor (TNF)-alpha and E-selectin, and histologically examined E-selectin expression and neutrophil accumulation.

RESULTS

In the edaravone group, hepatic lipid peroxidation and hepatic enzyme leakage were significantly less than in the saline group. Hepatic expression of TNF-alpha and E-selectin mRNAs was significantly lower in the edaravone than the saline group, at 2 h after initiation of reperfusion. Histologically, E-selectin immunoreactivity and neutrophil accumulation were less evident in hepatic sections from the edaravone group.

CONCLUSIONS

Edaravone reduced hepatic I/R injury by minimizing oxidative stress, and inhibited subsequent injurious inflammation by reducing expression of inflammatory cytokines and adhesion molecules.

Major hepatic trauma: warm ischemic tolerance of the liver after hemorrhagic shock

BACKGROUND

The management of severe hepatic trauma frequently involves exposing the liver to varying periods of warm ischemia. The ischemic tolerance of the liver, in the setting of hemorrhagic shock (HS) and trauma, is presently unknown. We tested the hypothesis that warm ischemic tolerance of the porcine liver will be decreased following resuscitation from HS.

MATERIALS AND METHODS

Twenty-three Yorkshire pigs were divided into three groups: 1) hepatic ischemia alone (HI, n = 9); 2) hemorrhagic shock alone (HS, n = 3); and 3) hemorrhagic shock plus hepatic ischemia combined (HSHI, n = 11). Following reperfusion, a liver biopsy was obtained and serial blood chemistries were sampled.

RESULTS

Post-operative day 7 mortality was increased in the HSHI group (7/11) compared to the HI (0/9) group, P = 0.038. Notably, deaths did not result from acute liver failure, but rather from intra-operative hemodynamic collapse shortly following hepatic reperfusion. In addition, the HSHI group experienced significantly elevated lactic acid, serum creatinine and liver enzyme levels. Analysis of the liver biopsy samples is consistent with a more severe liver injury in the HSHI group.

CONCLUSIONS

The warm ischemic tolerance of the liver following resuscitation from HS is significantly decreased in this porcine model compared to HS or HI alone. Mortality was associated with acute intra-operative hemodynamic collapse occurring shortly after hepatic reperfusion.

Liver resective surgery: a multivariate analysis of postoperative outcome and complication

INTRODUCTION

Notwithstanding technical advances and high experience of liver resection of specialized centers, the rate of complications after surgical resection could be high. In this study, we analyzed causes and foreseeable risk factors linked to postoperative morbidity on the ground of data derived from a single center surgical population.

MATERIALS AND METHODS

From September 1989 to March 2005, 134 consecutive patients had liver resection for Hcc and 153 consecutive patients with liver metastasis (derived from either colorectal cancer or noncolorectal cancer) at our department. We performed 22 major hepatectomy, 20 left hepatectomy, 14 trisegmentectomy, 77 bisegmentectomy and/or left lobectomy, 74 segmentectomy, and 80 wedge resection.

RESULTS

In-hospital mortality rate was 4.5%, about 7% in Hcc cases and 2.6% in liver metastasis. Morbidity rate was 47.7%, caused by the rising of ascites (10%), temporary impairment liver function (19%), biliary fistula (6%), hepatic abscess (25%), hemoperitoneum (10%), and pleural effusion (30%) sometimes combined each other. Some variables, associated with the technical aspects of surgical procedure, are responsible of the rising of complication as: Pringle maneuver length of more than 20 minutes (p=0.001); the type of liver resection procedure [major hepatectomy (p=0.02), left hepatectomy (p=0.04), trisegmentectomy (p=0.04), bisegmentectomy and/or left lobectomy (p=0.04)]; and the request of an amount of blood transfusion of more than 600 cc (p=0.04). Also, both liver dysfunction, in particular Child A vs B and C (p=0.01), and histopathological grading (p=0.01) are associated with a high rate of postsurgical complication in Hcc cases.

CONCLUSION

We make the following recommendations: every liver resection should be planned after intraoperative ultrasonography, anatomical surgical procedure should be preferred instead of wedge resection, and modern devices should be used, like Argon Beam and Ligasure dissector, to reduce the incidence of both intraoperative and postoperative bleeding and biliary leakage.

Intermittent hepatic ischemia-reperfusion minimizes liver metastasis in rats

BACKGROUND

Surgical stresses, including hepatic ischemia-reperfusion (I/R), promote cancer growth and metastasis. We have reported that continuous hepatic I/R increases liver damage and promoted liver metastasis from colon cancer, whereas intermittent I/R causes less liver damage. We therefore examined whether intermittent I/R could reduce liver metastasis in a rat model.

MATERIALS AND METHODS

Adult male Fischer rats was divided between three groups: group A (control), which received laparotomy for 120 min with no liver ischemia; group B (continuous I/R), which received 60 min of 70% partial liver ischemia followed by 60 min of reperfusion; and group C (intermittent I/R), which received 15 min of 70% ischemia and 15 min of reperfusion, repeated four times. Just before closing the abdomen, all animals were inoculated intrasplenically with rat colon adenocarcinoma cells (RCN-H4). Tumor nodules on the liver surface were counted 3 weeks later. In addition, expression of E-selectin mRNA in liver was examined at 1, 3, and 6 h after completing I/R by a reverse transcription-polymerase chain reaction.

RESULTS

Continuous I/R (B) greatly promoted liver metastasis in both ischemic and nonischemic liver lobes, whereas intermittent I/R (C) showed significantly fewer metastasis than group B in both lobes. Significantly less E-selectin mRNA was expressed in group C than in group B.

CONCLUSIONS

Intermittent I/R limits expression of E-selectin mRNA and liver metastasis. Intermittent hepatic I/R is less stressful than continuous I/R, minimizing liver metastasis by colon cancer cells through avoidance of E-selectin up-regulation.

Isquemia hepática normotérmica em ratos: estudo da lesão celular através do uso de clampeamento pedicular contínuo e intermitente

OBJETIVO: Avaliar as alterações bioquímicas decorrentes da isquemia hepática normotérmica, seguida de reperfusão em duas modalidades de clampeamento da tríade portal em ratos. MÉTODO: Trinta ratos Wistar machos pesando entre 250 e 320 gramas foram divididos em três grupos de 10 animais cada. Induzimos 40 minutos de isquemia hepática por clampeamento pedicular contínuo (grupo I) ou intermitente (grupo II). No grupo controle não houve clampeamento. Como parâmetro de lesão hepatocelular adotamos a concentração plasmática de: transaminase glutâmico oxalacética (TGO), transaminase glutâmico pirúvica (TGP) e lactato desidrogenase (LDH). Colhemos as amostras de sangue no início (T1) e no final da cirurgia (T2). Todos os animais foram submetidos ao mesmo tempo operatório: 60 minutos. RESULTADOS: Não houve diferença estatística nos valores iniciais (T1) das três enzimas nos três grupos. Todos apresentaram aumento significativo das enzimas do momento 1 (T1) para o momento 2 (T2). Houve diferença estatística no aumento médio de TGO e TGP entre os três grupos, sendo o maior aumento encontrado no grupo I e o menor, no grupo controle. Não houve diferença significativa, em relação à LDH, entre o grupo II e o grupo controle. No grupo I, entretanto, houve aumento significativo em relação aos demais. Conclusão: Comparado ao clampeamento contínuo, para um período total de 40 minutos de isquemia, o clampeamento da tríade portal em ratos realizado de forma intermitente, com ciclos de 10 minutos de isquemia e 5 minutos de reperfusão, provoca menor dano hepatocelular, o que foi constatado pela menor alteração enzimática.

Protective effect of ischemic preconditioning against intermittent warm-ischemia-induced liver injury

BACKGROUND

Although ischemic preconditioning (IPC) has been reported to protect the liver from injury when subjected to continuous hepatic ischemia, whether IPC protects rat livers against ischemia-reperfusion (I/R) injury after intermittent ischemia has not been elucidated.

MATERIALS AND METHODS

Five groups of Wistar rats were subjected to intermittent hepatic ischemia (I) comprising 15-min ischemia and 5-min reperfusion three times with or without prior IPC (10-min ischemia and 10-min reperfusion), 45-min continuous ischemia (C) with or without IPC, and sham operation. Serum transaminase and lactic acid levels, hepatic tissue energy charges, and hepatic blood perfusion were measured after reperfusion. Plasma tumor necrosis factor-alpha (TNF-alpha) levels were determined after reperfusion for 120 min. Histological and apoptotic findings were evaluated after reperfusion for 180 min.

RESULTS

IPC significantly reduced serum transaminase levels after continuous and intermittent ischemia (IPC + C, 1107 vs C, 2684 IU/l; IPC + I, 708 vs I, 1859 IU/l). After hepatic ischemia without IPC, apoptosis and necrosis with increased plasma TNF-alpha levels were observed. IPC protected livers from injury by interfering with the increase in plasma TNF-alpha (IPC + I, 27.6 vs I, 64.8 pg/ml; IPC + C, 21.6 vs C, 49.3 pg/ml). This resulted in the attenuation of hepatic necrosis after continuous ischemia and significantly reduced necrosis and apoptosis after intermittent ischemia.

CONCLUSIONS

IPC exerts a greater protective effect against hepatic I/R injury after intermittent hepatic ischemia than after continuous hepatic ischemia.

Hepatic ischemia-reperfusion promotes liver metastasis of colon cancer

BACKGROUND

The effects of hepatic ischemia/reperfusion (I/R) on liver metastasis have not been fully examined. We examined hepatic I/R and liver metastasis of colorectal cancer in a rat model; we also quantitated expression of E-selectin (ELAM-1) mRNA after I/R.

MATERIALS AND METHODS

Rats underwent 30 or 60 min of 70% partial hepatic ischemia. After 60 min of reperfusion, rat colon adenocarcinoma cells (RCN-H4) were inoculated intrasplenically. The number of tumor nodules on the liver surface was determined 3 weeks later. Expression of E-selectin mRNA was determined at 1, 3, and 6 h after ischemia by quantitative RT-PCR.

RESULTS

Hepatic I/R promoted liver metastasis of RCN-H4 and induced the expression of E-selectin mRNA in both clamped and unclamped liver lobes. The number of tumor nodules and the expression of E-selectin mRNA after 60 min of ischemia was greater than that after 30 min.

CONCLUSIONS

Hepatic I/R, especially with a long duration of ischemia, induces expression of E-selectin and promotes liver metastasis of colon cancer in rats.

Resection of liver tumors: technical aspects

The resection of primary and secondary liver tumors has become accepted as the only curative therapy that can be offered to patients with these cancers. Technical advances made over the last two decades have improved the ability of the surgeon to perform these procedures with decreased morbidity. This article reviews hepatic anatomy, the preoperative evaluation of patients and various technical aspects involved in liver resections. The latter includes the role of intraoperative ultrasound and techniques of vascular occlusion and hepatic parenchymal dissection.