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Hirose S, Tsuruya K, Shimma Y, Arase Y, Takashimizu S, Nishizaki Y, Shiraishi K, Watanabe N, Matsuzaki S, Ieda S, Kagawa T. Antiviral Therapy for Patients Chronically Infected with Hepatis C Virus at Tokai University Hospital. THE TOKAI JOURNAL OF EXPERIMENTAL AND CLINICAL MEDICINE 2022; 47:64-71. [PMID: 35801550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/02/2022] [Indexed: 06/15/2023] [Imported: 08/29/2023]
Abstract
OBJECTIVE Hepatitis C virus (HCV) was identified in 1989. In 2020, three decades after HCV identification, three researchers won the Nobel Prize in Physiology or Medicine for the discovery of this virus. In 1992, three years after the discovery, interferon (IFN) was launched as the first anti-HCV therapy in Japan; however, the efficacy of IFN therapy was far from acceptable due to severe adverse effects. The advent of IFN-free direct-acting antivirals (DAAs) in 2014 dramatically improved the outcomes of antiviral treatment without serious adverse effects. In this study, we aimed to summarize anti-HCV therapy at the Tokai University Hospital. METHODS We identified patients who underwent anti-HCV therapy by searching medical records from January 1992 to December 2020, analyzed their background, and compared safety and efficacy among treatments. RESULTS A total of 1777 treatments were given to 1299 patients. The sustained virologic response rate has dramatically increased over the past 30 years, with only 7% for IFN monotherapy and 95% or higher for recent IFN-free DAA therapies. CONCLUSIONS We documented the results of anti-HCV therapy at the Tokai University Hospital. In the 30 years since the discovery of HCV, surprisingly successful progress has been accomplished in the anti-HCV treatment.
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Chuma M, Yokoo H, Hiraoka A, Ueda K, Yokoyama T, Tsuji K, Shimada N, Uojima H, Kobayashi S, Hattori N, Okubo T, Atsukawa M, Ishikawa T, Takaguchi K, Tsutsui A, Toyoda H, Tada T, Saito Y, Hirose S, Tanaka T, Takeda K, Otani M, Sekikawa Z, Watanabe T, Hidaka H, Morimoto M, Numata K, Kagawa T, Sakamoto M, Kumada T, Maeda S. Identification of CT Values That Could Be Predictive of Necrosis (N-CTav) in Hepatocellular Carcinoma after Lenvatinib Treatment. Curr Oncol 2022; 29:3259-3271. [PMID: 35621656 PMCID: PMC9139739 DOI: 10.3390/curroncol29050266] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/20/2022] [Accepted: 04/21/2022] [Indexed: 02/05/2023] [Imported: 08/29/2023] Open
Abstract
Purpose: To assess the utility of measurement of the computed tomography (CT) attenuation value (CTav) in predicting tumor necrosis in hepatocellular carcinoma (HCC) patients who achieve a complete response (CR), defined using modified Response Evaluation Criteria in Solid Tumors (mRECIST), after lenvatinib treatment. Method: We compared CTav in arterial phase CT images with postoperative histopathology in four patients who underwent HCC resection after lenvatinib treatment, to determine CTav thresholds indicative of histological necrosis (N-CTav). Next, we confirmed the accuracy of the determined N-CTav in 15 cases with histopathologically proven necrosis in surgical specimens. Furthermore, the percentage of the tumor with N-CTav, i.e., the N-CTav occupancy rate, assessed using Image J software in 30 tumors in 12 patients with CR out of 571 HCC patients treated with lenvatinib, and its correlation with local recurrence following CR were examined. Results: Receiver operating characteristic (ROC) curve analysis revealed an optimal cut-off value of CTav of 30.2 HU, with 90.0% specificity and 65.0% sensitivity in discriminating between pathologically identified necrosis and degeneration, with a CTav of less than 30.2 HU indicating necrosis after lenvatinib treatment (N30-CTav). Furthermore, the optimal cut-off value of 30.6% for the N30-CTav occupancy rate by ROC analysis was a significant indicator of local recurrence following CR with 76.9% specificity and sensitivity (area under the ROC curve; 0.939), with the CR group with high N30-CTav occupancy (≥30.6%) after lenvatinib treatment showing significantly lower local recurrence (8.3% at 1 year) compared with the low (<30.6%) N30-CTav group (p < 0.001, 61.5% at 1 year). Conclusion: The cut-off value of 30.2 HU for CTav (N30-CTav) might be appropriate for identifying post-lenvatinib necrosis in HCC, and an N30-CTav occupancy rate of >30.6% might be a predictor of maintenance of CR. Use of these indicators have the potential to impact systemic chemotherapy for HCC.
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Mashiko T, Masuoka Y, Nakano A, Tsuruya K, Hirose S, Hirabayashi K, Kagawa T, Nakagohri T. Intussusception due to hematogenous metastasis of hepatocellular carcinoma to the small intestine: A case report. World J Gastroenterol 2020; 26:6698-6705. [PMID: 33268957 PMCID: PMC7673968 DOI: 10.3748/wjg.v26.i42.6698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/23/2020] [Accepted: 10/13/2020] [Indexed: 02/06/2023] [Imported: 08/29/2023] Open
Abstract
BACKGROUND The commonest sites of extrahepatic metastases from hepatocellular carcinoma (HCC) are the lungs, bones, adrenal glands, and regional lymph nodes. Hematogenous metastasis to the gastrointestinal (GI) tract is a rare condition in patients with HCC, and the prognosis is usually poor. We report, herein, an extremely rare case of a patient with intussusception due to hematogenous metastasis of HCC to the ileum and his long-term survival with multidisciplinary therapy.
CASE SUMMARY The patient was a 71-year-old man with a history of chronic hepatitis B, who had undergone three surgeries for HCC. He was treated with sorafenib for peritoneal metastases of HCC. He was admitted to our hospital with chief complaints of abdominal pain and vomiting. Abdominal contrast-enhanced computed tomography imaging revealed a small intestinal tumor, presenting with intussusception and small bowel obstruction. Conservative treatment was started, but due to repeated exacerbation of symptoms, surgery was planned on the 28th d of hospitalization. Partial ileal resection without reducing the intussusception and end-to-end anastomosis was performed. On histological examination, tumor cells were not observed on the serosal surface, but intravascular invasion of tumor cells was seen. Immunohistochemistry was positive for immunohistochemical markers, and a diagnosis of hematogenous metastasis of HCC to the ileum was made. He remains alive 82 mo after the first surgery.
CONCLUSION Prognosis of HCC patients with GI tract metastasis is usually poor, but in some cases, multidisciplinary therapy may prolong survival.
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Shomura M, Okabe H, Sato E, Fukai K, Shiraishi K, Hirose S, Tsuruya K, Arase Y, Anzai K, Kagawa T. Hypothyroidism is a Predictive Factor for Better Clinical Outcomes in Patients with Advanced Hepatocellular Carcinoma Undergoing Lenvatinib Therapy. Cancers (Basel) 2020; 12:cancers12113078. [PMID: 33105621 PMCID: PMC7690372 DOI: 10.3390/cancers12113078] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 10/16/2020] [Indexed: 02/07/2023] [Imported: 08/29/2023] Open
Abstract
Simple Summary Patients with advanced hepatocellular carcinoma (HCC) undergoing molecular targeted therapy often experience non-negligible adverse events (AEs). Paradoxically, certain AEs are reportedly associated with a good prognosis. We aimed to identify factors predictive of treatment duration and overall survival (OS) in patients with HCC undergoing lenvatinib therapy. This study suggested that better baseline liver function was predictive of longer treatment duration and better prognosis in patients with advanced HCC treated with lenvatinib. Moreover, an AE of Grade 2/3 hypothyroidism was associated with a better prognosis in patients receiving lenvatinib treatment for advanced HCC. Continuing anticancer therapy with appropriate thyroid hormone replacement may contribute to longer survival. Abstract Patients with advanced hepatocellular carcinoma (HCC) undergoing molecular targeted therapy often experience non-negligible adverse events (AEs). Paradoxically, certain AEs are reportedly associated with a good prognosis. We aimed to identify factors predictive of treatment duration and overall survival (OS) in patients with HCC undergoing lenvatinib therapy. Forty-six consecutive patients with advanced HCC who received lenvatinib therapy from April 2018 to November 2019 were prospectively followed until November 2019. Treatment efficacy was assessed according to the modified Response Evaluation Criteria in Solid Tumors for 2–3 months after therapy initiation. The disease control rate (DCR) was defined as the percentage of patients with a complete response, partial response, or stable disease. The DCR was 65.2%, with a median survival of 10.2 months. Grade 2/3 hypoalbuminemia resulted in shorter treatment duration. Factors predictive of longer OS were a Child-Pugh score of 5 at baseline and the occurrence of Grade 2/3 hypothyroidism. Conversely, Grade 2/3 hypoalbuminemia was associated with a poorer prognosis. An AE of Grade 2/3 hypothyroidism was associated with a better prognosis in patients receiving lenvatinib treatment for advanced HCC. Continuing anticancer therapy with appropriate thyroid hormone replacement may contribute to longer OS.
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Anzai K, Tsuruya K, Morimachi M, Arase Y, Hirose S, Hirabayashi K, Adachi Y, Kagawa T. The Impact of a Heterozygous SLCO1B3 Null Variant on the Indocyanine Green Retention Test. J Pharm Sci 2020; 109:3206-3209. [PMID: 32593714 DOI: 10.1016/j.xphs.2020.06.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 11/26/2022] [Imported: 08/29/2023]
Abstract
Indocyanine green (ICG) retention test is widely used for preoperative evaluation of liver function. OATP1B3 (gene symbol: SLCO1B3) is the major transporter for hepatic ICG uptake. We previously demonstrated that the individuals with a homozygous SLCO1B3 null allele revealed markedly impaired ICG clearance. However, the effect of heterozygosity of this variant on ICG clearance remains unknown. We compared the results of ICG retention rate at 15 min (ICG-R15) and hepatic OATP1B3 expression among individuals whose SLCO1B3 genotype was determined. Although OATP1B3 expression was significantly lower in the heterozygosity than the wild-type, the ICG-R15 results were comparable; 8.4 ± 3.4 (mean ± SD) % in the heterozygosity and 8.7 ± 6.0% in the wild-type. A homozygous individual revealed markedly high ICG-R15 (79.8%) and lacked OATP1B3 expression. In conclusion, the individuals with a heterozygous SLCO1B3 null variant had similar ICG clearance capacity to those with the wild-type despite decreased hepatic OATP1B3 expression.
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Chuma M, Uojima H, Numata K, Hidaka H, Toyoda H, Hiraoka A, Tada T, Hirose S, Atsukawa M, Itokawa N, Arai T, Kako M, Nakazawa T, Wada N, Iwasaki S, Miura Y, Hishiki S, Nishigori S, Morimoto M, Hattori N, Ogushi K, Nozaki A, Fukuda H, Kagawa T, Michitaka K, Kumada T, Maeda S. Early Changes in Circulating FGF19 and Ang-2 Levels as Possible Predictive Biomarkers of Clinical Response to Lenvatinib Therapy in Hepatocellular Carcinoma. Cancers (Basel) 2020; 12:cancers12020293. [PMID: 31991869 PMCID: PMC7073176 DOI: 10.3390/cancers12020293] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 01/17/2020] [Accepted: 01/23/2020] [Indexed: 12/14/2022] [Imported: 08/29/2023] Open
Abstract
Predictive biomarkers of the response of hepatocellular carcinoma (HCC) to Lenvatinib therapy have not yet been clarified. The aim of this study was to identify clinically significant biomarkers of response to Lenvatinib therapy, to target strategies against HCC. Levels of circulating angiogenic factors (CAFs) were analyzed in blood samples collected at baseline and after introducing lenvatinib, from 74 Child-Pugh class A HCC patients who received lenvatinib. As CAF biomarkers, serum vascular endothelial growth factor (VEGF), fibroblast growth factor 19 (FGF19), FGF23, and angiopoietin-2 (Ang-2) were measured using enzyme-linked immunosorbent assays. Results: Significantly increased FGF19 (FGF19-i) levels and decreased Ang-2 (Ang-2-d) levels were seen in Lenvatinib responders as compared to non-responders (ratio of FGF19 level at 4 weeks/baseline in responders vs. non-responders: 2.09 vs. 1.32, respectively, p = 0.0004; ratio of Ang-2 level at four weeks/baseline: 0.584 vs. 0.810, respectively, p = 0.0002). Changes in FGF23 and VEGF levels at four weeks versus baseline, however, were not significantly different in responders versus non-responders. In multivariate analysis, the combination of serum FGF19-i and Ang-2-d was the most independent predictive factor for Lenvatinib response (Odds ratio, 9.143; p = 0.0012). Furthermore, this combination biomarker showed the greatest independent association with progression-free survival (Hazard ratio, 0.171; p = 0.0240). Early changes in circulating FGF19 and Ang-2 levels might be useful for predicting clinical response and progression-free survival in HCC patients on Lenvatinib therapy.
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Shao X, Uojima H, Setsu T, Okubo T, Atsukawa M, Furuichi Y, Arase Y, Hidaka H, Tanaka Y, Nakazawa T, Kako M, Kagawa T, Iwakiri K, Terai S, Koizumi W. Usefulness of autotaxin for the complications of liver cirrhosis. World J Gastroenterol 2020; 26:97-108. [PMID: 31933517 PMCID: PMC6952300 DOI: 10.3748/wjg.v26.i1.97] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/04/2019] [Accepted: 12/14/2019] [Indexed: 02/06/2023] [Imported: 08/29/2023] Open
Abstract
BACKGROUND Autotaxin (ATX) has been reported as a direct biomarker for estimating the evaluation of liver fibrosis. But available data on ATX as a useful biomarker for the complications of liver cirrhosis (LC) are scant.
AIM To assess the clinical usefulness of ATX for assessing the complications of LC.
METHODS This multicenter, retrospective study was conducted at six locations in Japan. We include patients with LC, n = 400. The ATX level was evaluated separately in men and women because of its high level in female patients. To assess the clinical usefulness of ATX for the complications of LC, the area under the curve (AUC) of ATX assessing for the severe complications was analyzed in comparison with the model for end-stage liver disease score, albumin-bilirubin (ALBI) score, fibrosis-4 index, and aspartate aminotransferase-to-platelet ratio index.
RESULTS The mean age was 68.4 ± 11.4 years, 240 patients (60.0%) were male. A total of 213 (53.3%) and 187 (46.8%) patients were compensated and decompensated, respectively. The numbers of patients with varix rupture, hepatic ascites, and hepatic encephalopathy were 35 (8.8%), 131 (32.8%), and 103 (25.8%), respectively. The AUCs of ATX in men for hepatic encephalopathy, hepatic ascites, and varix ruptures were 0.853, 0.816, and 0.706, respectively. The AUCs of ATX in women for hepatic encephalopathy, hepatic ascites, and varix rupture were 0.759, 0.717, and 0.697, respectively. The AUCs of ATX in men were higher than those in women, as were all the other biomarkers used to detect encephalopathy and varix ruptures. However, for detecting ascites, the AUC of ALBI in men was more effective than using ATX.
CONCLUSION ATX in men was more effective than any other biomarkers for detecting hepatic encephalopathy and varix ruptures.
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Uojima H, Arase Y, Itokawa N, Atsukawa M, Satoh T, Miyazaki K, Hidaka H, Sung JH, Kako M, Tsuruya K, Kagawa T, Iwakiri K, Horie R, Koizumi W. Relationship between response to lusutrombopag and splenic volume. World J Gastroenterol 2018; 24:5271-5279. [PMID: 30581275 PMCID: PMC6295839 DOI: 10.3748/wjg.v24.i46.5271] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/20/2018] [Accepted: 11/09/2018] [Indexed: 02/06/2023] [Imported: 08/29/2023] Open
Abstract
AIM To assess the correlation between the efficacy of lusutrombopag and clinical characteristics in patients with chronic liver disease. METHODS In this retrospective, multicenter study, which conducted at four locations in Japan, 50 thrombocytopenic patients with chronic liver disease were enrolled. All patients received oral lusutrombopag (3.0 mg/d for 7 d) for chronic liver disease. We assessed the increase in platelet count after the trial drug administration. A treatment response was defined as a platelet count ≥ 5 × 104/μL and an increased platelet count ≥ 2 × 104/μL from baseline after drug administration. We evaluated the response to lusutrombopag compared to baseline clinical characteristics in patients with chronic liver disease. RESULTS The numbers of responders and non-responders were 40 (80.0%) and 10 (20.0%), respectively. The patients were divided into a responder and non-responder group, and we added factors that may correspond to successful treatment with lusutrombopag. Splenic volume and body weight were lower in the responder group than in the non-responder group. White blood cell count and hemoglobin level were higher in responders compared with non-responders. Using a logistic regression model to assess the relationship between response to lusutrombopag and clinical characteristics, multivariate analysis confirmed that splenic volume was an independent factor that predicted the response of platelet counts (P = 0.025; odds ratio = 11.2; 95% confidence interval: 1.354-103.0). Splenic volume negatively correlated to changes in platelet count (r = -0.524, P = 0.001). CONCLUSION Splenic volume influences the change in platelet counts after administration of lusutrombopag in patients with chronic liver disease.
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Nagata N, Kagawa T, Hirose S, Arase Y, Tsuruya K, Anzai K, Shiraishi K, Mine T. Off-treatment durability of antiviral response to nucleoside analogues in patients with chronic hepatitis B. BMC Gastroenterol 2016; 16:38. [PMID: 26987437 PMCID: PMC4794926 DOI: 10.1186/s12876-016-0454-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 03/09/2016] [Indexed: 12/16/2022] [Imported: 08/29/2023] Open
Abstract
BACKGROUND Off-treatment durability of nucleoside analogue (NA) therapy in patients with chronic hepatitis B has not been well investigated. In this study we monitored antiviral effect of NA therapy and evaluated off-treatment durability after NA cessation in patients with chronic hepatitis B. PATIENTS AND METHODS A total of 94 consecutive patients (39 HBeAg-negative and 55 HBeAg-positive patients) who received NA therapy were followed up for approximately 9 years. We discontinued NA according to the following criteria; undetectable serum HBV-DNA by polymerase chain reaction (PCR) on three separate occasions at least 6 months apart in HBeAg-negative patients (APASL stopping recommendation), and seroconversion from HBeAg-positive to HBeAb-positive and undetectable serum HBV-DNA by PCR for at least 12 months in HBeAg-positive patients. RESULTS The cumulative rate of relapse after NA cessation was 48 % and 40 % in HBeAg-negative and -positive patients, respectively. Higher baseline serum alanine aminotransferase level was the only significant predictor for maintaining remission. No patients experienced decompensation after relapse. HBsAg loss occurred at an annual rate of 1.4 % and 0.4 % in HBeAg-negative and -positive patients, respectively. Hepatocellular carcinoma developed at an annual rate of 0.6 % in both HBeAg-negative and -positive patients. CONCLUSIONS Almost half of the patients did not relapse after cessation of NA therapy in both HBeAg-negative and -positive patients. Therefore, NA therapy could be discontinued with close monitoring if the APASL stopping recommendation is satisfied even in HBeAg-negative patients.
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Kagawa T, Hirose S, Arase Y, Oka A, Anzai K, Tsuruya K, Shiraishi K, Orii R, Ieda S, Nakazawa T, Tomita K, Hokari R, Miura S, Ebinuma H, Saito H, Kitamura T, Horie Y, Okuse C, Wasada M, Inoko H, Tohkin M, Saito Y, Maekawa K, Takikawa H, Mine T. No contribution of the ABCB11 p.444A polymorphism in Japanese patients with drug-induced cholestasis. Drug Metab Dispos 2015; 43:691-7. [PMID: 25713208 DOI: 10.1124/dmd.114.061325] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] [Imported: 08/29/2023] Open
Abstract
European studies have revealed that the ABCB11 c.1331T>C (V444A) polymorphism (rs2287622) C-allele frequency is higher among patients with drug-induced cholestasis. Given the low incidence of this disease, however, this association has not been sufficiently elucidated. We aimed to investigate the significance of this polymorphism in Japanese patients. We determined ABCB11 V444A polymorphism frequencies and HLA genotypes in two independent drug-induced cholestasis cohorts. Expression and taurocholate transport activity of proteins from 444A variants were analyzed using Madin-Darby canine kidney II cells. In cohort 1 (n = 40), the V444A polymorphism C-allele frequency (66%) was lower than that in controls (n = 190, 78%), but this difference was not significant (P = 0.09). In cohort 2 (n = 119), comprising patients with cholestatic (n = 19), hepatocellular (n = 74), and mixed (n = 26) liver injuries, the C-allele frequency was lower among patients with cholestatic liver injury (68%) than among those with hepatocellular (75%) or mixed liver injury (83%), although this difference was not significant. In cohort 1, HLA-A*0201 was observed more frequently in patients (22%) than in controls [11%; P = 0.003; odds ratio, 2.4 (95% confidence interval, 1.4-4.0)]. Taurocholate transport activity of 444A-encoded protein was significantly lower than that of 444V-encoded protein (81% of 444V, P < 0.05) because of the reduced protein stability. In conclusion, ABCB11 444A had slightly reduced transport activity, but it did not contribute to the occurrence of drug-induced cholestasis in Japanese patients. Therefore, genetic susceptibility to acquired cholestasis may differ considerably by ethnicity.
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Kagawa T, Orii R, Hirose S, Arase Y, Shiraishi K, Mizutani A, Tsukamoto H, Mine T. Ursodeoxycholic acid stabilizes the bile salt export pump in the apical membrane in MDCK II cells. J Gastroenterol 2014; 49:890-9. [PMID: 23722250 DOI: 10.1007/s00535-013-0833-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 05/03/2013] [Indexed: 02/04/2023] [Imported: 08/29/2023]
Abstract
BACKGROUND Ursodeoxycholic acid (UDCA) partly exerts choleretic effects by modifying the function of the bile salt export pump (Bsep, ABCB11). UDCA induces insertion of Bsep into the canalicular membrane of hepatocytes; however, underlying mechanisms remain unknown. We aimed to elucidate molecular mechanisms behind UDCA-induced Bsep activation. METHODS We established MDCK II cells stably expressing both Bsep and Na(+)-taurocholate cotransporting polypeptide, and investigated the effect of UDCA on activity and protein expression of Bsep using these cells. We performed inhibitor study to know the molecules involved in UDCA-induced Bsep activation, and also tested the influence of UDCA on Bsep having a disease-associated mutation. RESULTS UDCA activated Bsep in a dose-dependent manner. UDCA did not affect Bsep protein expression in whole cell lysates but increased its apical surface expression by extending the half-life from 2.4 to 5.0 h. This effect was specific to Bsep because UDCA did not affect other apical and basolateral proteins, and was independent of protein kinase A, adenylate cyclase, p38(MAPK), phosphatidylinositide 3-kinase, Ca(2+), and microtubules. NorUDCA activated Bsep similar to UDCA; however, cholic acid, taurocholic acid, and tauroUDCA had no effect. UDCA significantly increased the activity of Bsep with a benign recurrent intrahepatic cholestasis 2 mutation (A570T) but did not affect Bsep with a progressive familial intrahepatic cholestasis 2 mutation (G982R or D482G). CONCLUSIONS We demonstrated that UDCA stabilizes Bsep protein in the apical membrane and increases its activity in MDCK II cells, presumably by retarding the endocytotic process.
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