Reg3α and Reg3ß Expressions Followed by JAK2/STAT3 Activation Play a Pivotal Role in the Acceleration of Liver Hypertrophy in a Rat ALPPS Model.

To explore the underlying mechanism of rapid liver hypertrophy by liver partition in associating liver partition and portal vein ligation for staged hepatectomy (ALPPS), liver partition at different sites was investigated. Increased inflammatory cytokines owing to the liver partition have been reportedly responsible. If this were true, rapid liver hypertrophy should be achieved regardless of where the liver was split. A male Sprague-Dawley rat model was created, in which a liver split was placed inside the portal vein ligated lobe (PiLL), in addition to the ALPPS and portal vein ligation (PVL) models. Liver regeneration rate, inflammatory cytokine levels, activation status of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway and expressions of regenerating islet-derived (Reg)3α and Reg3ß were investigated. The liver regeneration rate was significantly higher in the ALPPS group than in the PiLL group, whereas inflammatory cytokine levels were nearly equal. Additional volume increase in ALPPS group over PVL and PiLL groups was JAK2/STAT3-dependent. Reg3α and Reg3ß expressions were observed only in the ALPPS group. An increase in inflammatory cytokines was not enough to describe the mechanism of rapid liver hypertrophy in ALPPS. Expressions of Reg3α and Reg3ß could play an important role in conjunction with an activation of the JAK2/STAT3 pathway.

Hepatic Stellate Cells Play a Functional Role in Exacerbating Ischemia-Reperfusion Injury in Rat Liver.

PURPOSE: The involvement of hepatic stellate cells (HSCs) with ischemia-reperfusion (I/R) injury in rat liver was examined using gliotoxin, which is known to induce HSC apoptosis. METHODS: Male Sprague-Dawley rats were used. HSC was represented by a glial fibrillary acidic protein (GFAP)-positive cell. Liver ischemia was produced by cross-clamping the hepatoduodenal ligament. The degree of I/R injury was evaluated by a release of aminotransferases. Sinusoidal diameter and sinusoidal perfusion rates were examined using intravital fluorescence microscopy. RESULTS: Gliotoxin significantly decreased the number of GFAP-positive cells 48 h after dosing (2.50 ± 0.19% [mean ± SD] in the nontreated group vs. 1.91 ± 0.46% in the gliotoxin-treated group). Liver damage was significantly suppressed by the pretreatment with gliotoxin. Sinusoidal diameters in zone 3 were wider in the gliotoxin group (10.25 ± 0.35 µm) than in the nontreated group (8.21 ± 0.50 µm). The sinusoidal perfusion rate was maintained as well in the gliotoxin group as in normal livers, even after I/R. CONCLUSIONS: Pretreatment with gliotoxin significantly reduced the number of HSCs in the liver and further suppressed liver injury following I/R. It is strongly suggested that HSCs play a functional role in exacerbating the degree of I/R injury of the liver.

Opportunistic use of a Foley catheter to provide a common electrocautery with a water-irrigating channel for hepatic parenchymal transection.

High-tech surgical energy devices that are used during a single surgery have increased in number and the expense for such disposable units is by no means negligible. We developed a handmade water-irrigating monopolar electrocautery using a Foley catheter to perform liver parenchymal transection. A commonly used 20-24 Fr Foley catheter was cut at a length of about 8 cm. The shaft of the 5 mm ball electrode measuring 13.5 cm in length was then inlaid into the urine drainage channel. The target tissues were cauterized without making an eschar, thereby preventing the adhesion of the electrode to the tissues. A ball electrode with our handmade water irrigation sheath can be made in only a few minutes at a very low cost, using common medical supplies and yielding satisfactory effects comparable to the use of specialized high-tech devices.

Nrf2 activation protects the liver from ischemia/reperfusion injury in mice.

OBJECTIVE: To investigate the role of Nrf2 in the pathogenesis of hepatic ischemia-reperfusion (I/R) injury. BACKGROUND: Hepatic I/R injury is a serious complication that leads to liver failure after liver surgery. NF-E2-related factor 2 (Nrf2) is a transcription factor that plays a critical role in protecting cells against oxidative stress. Therefore, it is suggested that Nrf2 activation protects the liver from I/R injury. METHODS: Wild-type and Nrf2-deficient mice were treated with 15-deoxy-Δ(12,14)-prostaglandin J2 (15d-PGJ2), or a vehicle. Subsequently, these mice were subjected to 60-minute hepatic 70% ischemia, followed by reperfusion. Liver and blood samples were collected to evaluate liver injury and mRNA expressions. RESULTS: After hepatic I/R, Nrf2-deficient livers exhibited enhanced tissue damage; impaired GSTm1, NQO1, and GCLc inductions; disturbed redox state; and aggravated tumor necrosis factor α mRNA expression in comparison with wild-type livers. 15d-PGJ2 treatment protected the livers of wild-type mice from I/R injury via increased expressions of GSTm1, NQO1, and GCLc; maintained redox status; and decreased tumor necrosis factor α induction. These effects induced by 15d-PGJ2 were not seen in the livers of Nrf2(-/-) mice and were not annulled by peroxisome proliferator-activated receptor γ antagonist in Nrf2(+/+) mice, suggesting that the protective effect of 15d-PGJ2 is mediated by Nrf2-dependent antioxidant response. CONCLUSIONS: Nrf2 plays a critical role in the mechanism of hepatic I/R injury and would be a new therapeutic target for preventing hepatic I/R injury during liver surgery.

Prognosis analysis of sarcomatous intrahepatic cholangiocarcinoma from a review of the literature.

BACKGROUND: Sarcomatous intrahepatic cholangiocarcinoma (ICC) is a rare histological variant of ICC. The prognosis of sarcomatous ICC is poorly understood. METHODS: We analyzed the prognosis of sarcomatous ICC by reviewing the previous reports and our own case. RESULTS: Only 15 cases of sarcomatous ICC have been reported in the English-language literature so far. Median survival time of patients with sarcomatous ICC with and without surgery was 11 and 3 months, respectively. Survival rate of patients operated on for sarcomatous ICC was similar to that of patients with ordinary ICC without surgery in the early postoperative period. In the long-term view, however, the prognosis for the patients with sarcomatous ICC receiving surgery was better than that for the patients with ordinary ICC without surgery. CONCLUSION: Although the prognosis for the patients with sarcomatous ICC was poor even after curative resection, surgery would be justified as the primary treatment for sarcomatous ICC.

High-dose corticosteroid therapy for erlotinib-induced interstitial lung disease in Japanese patient with advanced pancreatic cancer.

CONTEXT: Erlotinib is a selective epidermal growth factor receptor tyrosine kinase inhibitor used as a target therapy against non-small lung cancer and advanced pancreatic cancer. A regimen of erlotinib plus gemcitabine has been proven to prolong overall survival in the patient with advanced pancreatic cancer. In addition to common adverse effects, such as diarrhea, mucositis and skin rash (acne form eruptions), acute interstitial lung disease (ILD) has been reported as an infrequent but potentially fatal complication. We here report a case of a Japanese patient with erlotinib-induced ILD in whom high-dose corticosteroid therapy was successful. CASE REPORT: A fifty-five-year-old male with cancer of the head of the pancreas with multiple liver metastases started treatment with gemcitabine plus erlotinib. On the 13th day of erlotinib treatment, he had high fever. Chest computed tomography (CT) scan showed a diffuse ground-glass like infiltration of both lungs. He was diagnosed with ILD, and high-dose corticosteroid therapy was started. Two weeks after the introduction of steroid therapy, the reticular shadow faded away on CT. He was successfully treated with corticosteroid for erlotinib-induced acute ILD although he died 6 months after the initiation of chemotherapy owing to disease progression. CONCLUSION: we showed a case of a successfully treated Japanese patient of erlotinib-induced ILD. Because erlotinib-induced ILD would frequently occur in Japanese patients, closer attention to ILD should be paid for Japanese patients than in Western populations. If erlotinib-induced ILD occurs, a high-dose corticosteroid therapy would be a useful option of treatment.

Role of preferential cyclooxygenase-2 inhibition by meloxicam in ischemia/reperfusion injury of the rat liver.

BACKGROUND: Ischemia/reperfusion injury (IRI) is one of the major clinical problems in liver and transplant surgery. Livers subjected to warm ischemia in vivo often show a severe dysfunction and the release of numerous inflammatory cytokines and arachidonic acid metabolites. Cyclooxygenase (COX)-2 is the inducible isoform of an intracellular enzyme that converts arachidonic acid into prostaglandins. The aim of the study was to evaluate the effect of COX-2 inhibition and the role of Kupffer cells in IRI of the liver. METHODS: Male Wistar rats [250- 280 g body weight (BW)] were anesthetized and subjected to 30-min warm ischemia of the liver (Pringle's maneuver) and 60-min reperfusion after median laparotomy. The I/R group received no additional treatment. In the COX-2 inhibitor (COX-2I) group, the animals received 1 mg/kg BW meloxicam prior to operation. Gadolinium chloride (GdCl3) (10 mg/kg BW) was given 24 h prior to operation in the GdCl3 and GdCl3 + COX-2I groups for the selective depletion of Kupffer cells. The GdCl3 + COX-2I group received both GdCl3 and meloxicam treatment prior to operation. Blood and liver samples were obtained at the end of the experiments for further investigations. RESULTS: After 30 min of warm ischemia in vivo, severe hepatocellular damage was observed in the I/R group. These impairments could be significantly prevented by the selective COX-2 inhibition and the depletion of Kupffer cells. Alanine aminotransferase was significantly reduced upon meloxicam and GdCl3 treatment compared to the I/R group: I/R, 3,240 ± 1,262 U/l versus COX-2I, 973 ± 649 U/l, p < 0.001; I/R versus GdCl3, 1,611 ± 600 U/l, p < 0.05, and I/R versus GdCl3 + COX-2I, 1,511 ± 575 U/l, p < 0.01. Plasma levels of tumor necrosis factor alpha (TNF-α) were significantly reduced in the COX-2I treatment group compared to I/R (3.5 ± 1.5 vs. 16.3 ± 11.7 pg/ml, respectively; p < 0.05). Similarly, the amount of TxB2, a marker for COX-2 metabolism, was significantly reduced in the meloxicam treatment groups compared to the I/R group: I/R, 22,500 ± 5,210 pg/ml versus COX-2I, 1,822 ± 938 pg/ml, p < 0.001, and I/R versus GdCl3 + COX-2I, 1,530 ± 907 pg/ml, p < 0.001. All values are given as mean ± SD (n = 6). CONCLUSION: These results suggest that the inhibition of COX-2 suppressed the initiation of an inflammatory cascade by attenuating the release of TNF-α, which is an initiator of the inflammatory reaction in hepatic IRI. Therefore, we conclude that preferential inhibition of COX-2 is a possible therapeutic approach against warm IRI of the liver.

Diffusion-weighted MRI for differential diagnosis in gallbladder lesions with special reference to ADC cut-off values.

BACKGROUND/AIMS: We retrospectively evaluated the usefulness of the apparent diffusion coefficient (ADC) measured from high-b value diffusion-weighted imaging (DWI) of magnetic resonance imaging for the differential diagnosis of gallbladder lesions among patients with cancer, adenoma and inflammatory disease. METHODOLOGY: Forty patients with gallbladder lesions (22 patients with cancer, 7 patients with adenoma, and 11 patients with inflammatory disease) were enrolled in this study. All patients underwent high-b value DWI, and the ADC value was measured. The cut-off values were determined by receiver operating characteristic analysis. RESULTS: The ADC values of gallbladder cancers (1.31±0.57x10-3 mm2/s) were smallest and those of adenomas (2.66±0.43x10-3 mm2/s) were largest among the diseases. Inflammatory diseases took a middle position (1.97±0.54x10-3 mm2/s) between them. There were significant differences among the 3 groups of diseases (p<0.05). The cut-off value within ADC values to discriminate cancer from the other diseases was 1.64x10-3 mm2/s (accuracy 87.5%), and that to discriminate adenoma was 2.25x10-3 mm2/s (accuracy 90.0%). CONCLUSIONS: The ADC values measured from high-b value DWI would be useful for the differential diagnosis of gallbladder lesions.

Gastric cancer simultaneously complicated with extrahepatic bile duct metastasis and portal vein tumor thrombus: a case report.

BACKGROUND: Gastric cancer metastatic to the extrahepatic bile duct or accompanied by portal vein tumor thrombus (PVTT) is rare. To our knowledge, there have been no cases complicated with both of these factors. CASE PRESENTATION: A 72-year-old man presented with icterus and melena. A biochemical blood test showed abnormal values for hepatobiliary enzymes and a tumor marker, and abdominal computed tomography scan revealed wall thickening of the lower bile duct with intra- and extra-hepatic bile duct dilatation and PVTT. A biopsy of the lower bile duct during endoscopic retrograde cholangiopancreatography demonstrated a moderately differentiated tubular adenocarcinoma. Moreover, gastroduodenoscopy showed a type 3 tumor at the lesser curvature of the gastric antrum, and an endoscopic biopsy demonstrated a moderately differentiated tubular adenocarcinoma. We diagnosed concomitant gastric cancer and distal bile duct accompanied by PVTT, and pancreatoduodenectomy with combined resection of the portal vein was performed. The resected specimen revealed a tumor in the lesser curvature of the gastric antrum and circumferential wall thickening in the lower bile duct. In pathological findings, infiltration of a moderately differentiated tubular adenocarcinoma from the mucosal layer to the subserosal layer of the stomach was observed. In contrast, a moderately differentiated tubular adenocarcinoma demonstrating the same histological type as the gastric cancer had spread not to the mucosal layer but mainly to the fibromuscular layer of the lower bile duct. Immunohistochemical staining showed identical patterns between gastric cancer and the bile duct tumor: negativity for cytokeratin 7 (CK7), and positivity for CK19 and 20. Therefore, the final diagnosis was extrahepatic bile duct metastasis from gastric cancer with PVTT. Unfortunately, multiple liver metastases occurred in the early postoperative period and chemotherapy was conducted, but the patient died 12 months after the surgery. CONCLUSIONS: In the diagnosis of extrahepatic bile duct metastasis, immunohistochemical staining of gastric cancer and the bile duct tumor was essential and helpful as decisive evidence.

99mTc-GSA scintigraphy for assessing the functional volume ratio of the future liver remnant in the routine practice of liver resection.

BACKGROUND: The significance of incorporating regional functional heterogeneity assessment by liver scintigraphy into the calculation of the future liver remnant has been reported. However, liver scintigraphy entails additional costs and radiation exposure. Nevertheless, studies describing when liver scintigraphy demonstrates an actual benefit over computed tomography liver volumetry are lacking. Thus, we evaluated the degree of agreement between future liver remnant % values calculated by technetium 99mTc diethylenetriaminepentaacetic acid-galactosyl human serum albumin scintigraphy (galactosyl human serum albumin-based future liver remnant %) and those by computed tomography volumetry and investigated the practical impact of performing regional functional heterogeneity assessment. METHODS: The Bland-Altman method was used to retrospectively analyze the agreement between computed tomography- and galactosyl human serum albumin-based future liver remnant % measurements in 84 patients. RESULTS: In ordinary patients with a computed tomography-based future liver remnant % greater than 50%, there was a good agreement between both measurements. However, in cases with a computed tomography-based future liver remnant % less than 40%, galactosyl human serum albumin-based measurements were significantly smaller than computed tomography-based values, with 88% of these patients exhibiting a galactosyl human serum albumin-based future liver remnant % less than 30%. After portal vein embolization, galactosyl human serum albumin-based measurements were primarily greater than or in agreement with computed tomography-based values, even in cases with a computed tomography-based future liver remnant % less than 40%. CONCLUSION: Adding 99mTc diethylenetriaminepentaacetic acid-galactosyl human serum albumin scintigraphy to computed tomography liver volumetry is advised when deciding on hepatectomy in patients with a computed tomography-based future liver remnant % less than 50%. If the computed tomography-based future liver remnant % is smaller than 40%, it is strongly recommended to check future liver remnant % by 99mTc diethylenetriaminepentaacetic acid-galactosyl human serum albumin scintigraphy. In other cases, computed tomography-based future liver remnant % calculation alone can be regarded as the gold standard of safe hepatectomy.

Clinical and prognostic significance of urinary trypsin inhibitor in patients with hepatocellular carcinoma after hepatectomy.

BACKGROUND: Urinary trypsin inhibitor (UTI), produced in the liver, has been considered to suppress inflammation. The production of UTI may decrease after a hepatectomy and thereby increase the incidence of postoperative inflammation. This study investigated whether the changes in the UTI level affected the postoperative course in patients undergoing a hepatectomy for hepatocellular carcinoma (HCC). The prognostic significance of UTI was also analyzed. METHODS: The perioperative plasma UTI was measured in 25 HCC patients who underwent hepatic resection, and the correlation between the kinetics of UTI and clinicopathological factors was investigated. The expression of UTI in the resected specimens was examined by immunohistochemistry in 65 patients. Expression of UTI in the cancer cells were then correlated to both the liver pathology and the clinical outcomes in the corresponding patients. RESULTS: The plasma UTI level greatly decreased on the first postoperative day. This decrease significantly correlated with the resected tumor volume (r (s) = -.530, P = .006), but it had no influence on inflammatory complications. Immunohistochemistry revealed UTI expression in both noncancerous and cancerous lesions. An overexpression of UTI in HCC tissue was found to be an independent prognostic factor for early recurrence (P = .006). CONCLUSIONS: Although UTI plasma levels were noted to decrease after the removal of an HCC tumor, this decrease did not lead to an increase in inflammatory complications. However, overexpression of UTI in cancer was found to be a risk factor for tumor recurrence after resection, suggesting that UTI expression may be a useful prognostic marker.

Implication of protein kinase A for a hepato-protective mechanism of milrinone pretreatment.

BACKGROUND: We have previously reported that an increase of adenosine 3',5'-cyclic monophosphate (cAMP) in liver tissue after an administration of milrinone, a phosphodiesterase-3 inhibitor attenuates hepatic warm ischemia-reperfusion injury. The aim of this study was to determine whether cAMP-dependent protein kinase (protein kinase A) activation was involved in the milrinone-induced hepatoprotective effect on an ischemia-reperfusion injury in an in vivo model. MATERIALS AND METHODS: Male Lewis rats were allocated into 3 groups. In Group M, milrinone was administrated before ischemia; in Group I, a protein kinase A inhibitor, adenosine 3',5'-cyclic monophosphorothioate, 8-bromo-, Rp-isomer, sodium salt (Rp-8-Br-cAMPS), was injected prior to the administration of milrinone; and in Group C, the control group, there was no pretreatment. After pretreatment, all rats were exposed to a 45-min total hepatic inflow occlusion. RESULTS: After milrinone administration, liver cAMP concentrations and protein kinase A activity ratios were elevated. They protected the liver from ischemia-reperfusion injury. Rp-8-Br-cAMPS suppressed protein kinase A activation without affecting cAMP elevating responses to milrinone. Compared with Group C, hepatocellular necrosis, neutrophil infiltration, and congestion were ameliorated, and serum tumor necrosis factor-alpha, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase levels were significantly suppressed in Group M. Rp-8-Br-cAMPS canceled this effect, showing histological damages in Group I as severe as in Group C. The levels of tumor necrosis factor-alpha, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase were the same in Groups C and I. CONCLUSIONS: Activation of protein kinase A might play an important role in the mechanism of milrinone-induced ischemic tolerance in the liver.

[A case of surgical treatment for solitary lymph node recurrence of hepatocellular carcinoma simultaneously developed in the mediastinum and abdominal cavity].

We report a surgically treated case of lymph node recurrence from hepatocellular carcinoma (HCC) that occurred simultaneously but individually in the mediastinum and abdominal cavity with no metastasis. A 52-year-old man had undergone left lateral segmentectomy for poorly differentiated HCC. Three months after surgery, abdominal computed tomography revealed an enlarged solitary lymph node along the common hepatic artery. Another isolated mediastinal lymph node was also positive on whole body 18F-fluorodeoxyglucose positron emission tomography. Because no other metastatic lesions were identified, we resected these two lymph nodes under a diagnosis of lymph node metastases from HCC. Histopathologically, both of them were classified as poorly differentiated HCC with solid growth. No further recurrence has been found during 20-month follow-up period. Our experience suggested that even though metastatic lymph nodes of HCC were present in the mediastinum and abdominal cavity, resection may provide survival benefit if each metastasis is individually solitary.

Effect of Lansoprazole on the Control of the Intragastric pH in a Patient with Short Bowel Syndrome.

A 40-year-old man suffered from short bowel syndrome. Since a large amount of intestinal output and watery diarrhea hampered his quality of life, we tried to control the intestinal output by reducing the secretion of gastric acid with lansoprazole. Because the small intestine was only 10 cm in length and effective absorption of oral lansoprazole was doubtful, we monitored his intragastric pH for 24 hours and confirmed that the holding time above pH 3.0 was 14.5 hours (60.4%). He spent his home life eating porridge during the day, and receiving total parenteral nutrition of 1,100 mL/day at night while taking lansoprazole as an oral tablet (30 mg) once a day.

A newly designed magnet-retracting forceps for laparoscopic cholecystectomy in a swine model.

We designed a method for remote-controlled endoscopic surgery using magnet-retracting forceps. To evaluate the feasibility of this technique, laparoscopic cholecystectomy was attempted in a swine model. This method takes advantage of the attractive force between two magnets, one inserted into the peritoneal cavity and the other located outside the abdominal wall. An intra-peritoneal magnet was fixed to the fundus of the gallbladder using an endovascular clip. Laparoscopic cholecystectomy was accomplished by magnetic retraction of the gallbladder. This magnet-retracting forceps provided port-less access to the abdominal cavity. Since the direction and range of retraction were unrestricted by the location of access-ports fixed on the abdominal wall, surgery could be less invasive. In addition, this procedure provided surgeons with excellent endoscopic views, as retraction force was supplied without any shaft device in the abdomen. This operation system using magnetic retraction appears promising.

Domino Reconstruction of the Portal Vein Using the External Iliac Vein and an ePTFE Graft in Pancreatic Surgery.

BACKGROUND: In the portal vein resection of long distance, an interposition by autologous vein is mandatory. External iliac vein (EIV) has been used, but harvesting the EIV is associated with severe venous congestion of the affected lower extremity. We have reconstructed the EIV using a ringed expanded polytetrafluoroethylene (ePTFE) graft. METHODS: Thirteen patients underwent this surgery. The right EIV was used for reconstructing the portal vein, and the retrieved portion of EIV was interposed by the ePTFE graft. We evaluated size and length of the graft, graft patency, girth of thigh, time for reconstruction of EIV, and graft infection. RESULTS: ePTFE grafts of 8 or 10 mm in diameter were used. The length of ePTFE graft used was 4.4 ± 0.5 cm. Graft patency was kept in 76.9% patients. Graft obstruction was encountered in three patients, and the girth of right thigh increased by about 10 cm. Time for reconstruction of EIV was 29.5 ± 6.8 min. Graft infection did not occur in any patients. CONCLUSIONS: Reconstruction of the EIV using a ringed ePTFE graft seems to be a feasible option for preventing the swelling of the affected lower extremity after procurement of EIV for repairing the portal vein.

Usefulness of Oblique Multiplanar Images on Multi-Detector Computed Tomography for Diagnosing Intersigmoid Hernia.

BACKGROUND: Intersigmoid hernia is a hernia of the small intestine into the intersigmoid fossa. Because the cavity of the intersigmoid fossa is so small, the preoperative detection of incarcerated intestine and/or mesenteric convergence is very difficult. We report a case of intersigmoid hernia in which the incarcerated bowel and mesenteric convergence could be visualized by oblique multiplanar reconstruction (MPR) images on multi-detector computed tomography (MDCT). CASE REPORT: An 82-year-old man with small bowel obstruction was treated conservatively with a long intestinal tube. Axial plane images of MDCT detected only a thickening of the small bowel wall and a narrowing of the lumen in the pelvis. Since a fourteen-day waiting period did not improve the condition at all, he underwent surgery. The small bowel was herniated into the intersigmoid fossa. After surgery, we studied the preoperative images of MDCT once again. However, neither converged mesentery nor hernia orifice had been depicted. We attempted to make oblique coronal/sagittal MPR images using SYNAPSE VINCENT® and succeeded in visualizing not only the incarcerated bowels but also the hernia orifice and mesenteric convergence. CONCLUSION: Creating oblique MPR images from the MDCT volume data would help in making a preoperative diagnosis of sigmoid mesocolon hernias such as intersigmoid hernia with increasing confidence.

Serum Amyloid A Induces Inflammation, Proliferation and Cell Death in Activated Hepatic Stellate Cells.

Serum amyloid A (SAA) is an evolutionary highly conserved acute phase protein that is predominantly secreted by hepatocytes. However, its role in liver injury and fibrogenesis has not been elucidated so far. In this study, we determined the effects of SAA on hepatic stellate cells (HSCs), the main fibrogenic cell type of the liver. Serum amyloid A potently activated IκB kinase, c-Jun N-terminal kinase (JNK), Erk and Akt and enhanced NF-κB-dependent luciferase activity in primary human and rat HSCs. Serum amyloid A induced the transcription of MCP-1, RANTES and MMP9 in an NF-κB- and JNK-dependent manner. Blockade of NF-κB revealed cytotoxic effects of SAA in primary HSCs with signs of apoptosis such as caspase 3 and PARP cleavage and Annexin V staining. Serum amyloid A induced HSC proliferation, which depended on JNK, Erk and Akt activity. In primary hepatocytes, SAA also activated MAP kinases, but did not induce relevant cell death after NF-κB inhibition. In two models of hepatic fibrogenesis, CCl4 treatment and bile duct ligation, hepatic mRNA levels of SAA1 and SAA3 were strongly increased. In conclusion, SAA may modulate fibrogenic responses in the liver in a positive and negative fashion by inducing inflammation, proliferation and cell death in HSCs.

Differential requirement for c-Jun NH2-terminal kinase in TNFalpha- and Fas-mediated apoptosis in hepatocytes.

The c-Jun NH2-terminal kinase (JNK) is involved in the regulation of cell death, but its role in tumor necrosis factor (TNF)-alpha- and Fas-mediated apoptosis in primary cells is not well defined. In primary rat hepatocytes expressing an IkappaB superrepressor, the JNK inhibitor SP600125 strongly decreased TNF-alpha-induced cell death, caspase 3 activation, and DNA laddering. In contrast, SP600125 did not rescue mouse hepatocytes from Fas-induced apoptosis. Apoptosis in mouse hepatocytes, induced by human TNF-alpha, was blocked by SP600125, indicating that TNF-receptor (TNF-R) 1-mediated JNK activation is important for TNF-alpha-induced death. However, mouse TNF-alpha was more efficient than human TNF-alpha in activating JNK and killing mouse hepatocytes, suggesting that TNF-R1 and TNF-R2 cooperate in JNK activation and apoptosis. SP600125 rescued actinomycin D-pretreated hepatocytes and hepatocytes expressing a dominant negative c-Jun from TNF-alpha, indicating that JNK exerts its proapoptotic effect independently of transcription and c-Jun. SP600125 delayed the mitochondrial permeability transition, inhibited cytochrome c release and prevented bid degradation after TNF-alpha, suggesting that JNK-regulated proapoptotic factors act upstream of the mitochondria. Moreover, overexpression of JNK1 activated a mitochondrial death pathway in hepatocytes, albeit less efficiently than TNF-alpha. This study demonstrates that JNK augments TNF-alpha-induced apoptosis in hepatocytes through a signaling pathway that is distinct from the pathway by which it regulates proliferation.