Publications by authors named "Kojiro Nakamura"

39 Publications

Myeloid Ikaros-SIRT1 signaling axis regulates hepatic inflammation and pyroptosis in ischemia-stressed mouse and human liver.

J Hepatol 2021 Dec 3. Epub 2021 Dec 3.

Dumont-UCLA Transplantation Center, Department of Surgery, Division of Liver and Pancreas Transplantation, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA. Electronic address:

Background & Aims: Although Ikaros (IKZF1) is a well-established transcriptional regulator in leukocyte lymphopoiesis and differentiation, its role in myeloid innate immune responses remains unclear. Sirtuin 1 (SIRT1) is a histone/protein deacetylase involved in cellular senescence, inflammation, and stress resistance. Whether SIRT1 signaling is essential in myeloid cell activation remains uncertain, while the molecular communication between Ikaros and SIRT1, two major transcriptional regulators, has not been studied.

Methods: We undertook molecular and functional studies to interrogate the significance of the myeloid Ikaros-SIRT1 axis in innate immune activation and whether it may serve as a homeostatic sentinel in human liver transplant recipients (hepatic biopsies) and murine models of sterile hepatic inflammation (liver warm ischemia-reperfusion injury in wild-type, myeloid-specific Sirt1-knockout, and CD11b-DTR mice) as well as primary bone marrow-derived macrophage (BMM) cultures (Ikaros silencing vs. overexpression).

Results: In our clinical study, we identified increased post-reperfusion hepatic Ikaros levels, accompanied by augmented inflammasome signaling yet depressed SIRT1, as a mechanism of hepatocellular damage in liver transplant recipients. In our experimental studies, we identified infiltrating macrophages as the major source of Ikaros in IR-stressed mouse livers. Then, we demonstrated that Ikaros-regulated pyroptosis - induced by canonical inflammasome signaling in BMM cultures - was SIRT1 dependent. Consistent with the latter, myeloid-specific Ikaros signaling augmented hepatic pyroptosis to aggravate pro-inflammatory responses in vivo by negatively regulating SIRT1 in an AMPK-dependent manner. Finally, myeloid-specific SIRT1 was required to suppress pyroptosis, pro-inflammatory phenotype, and ultimately mitigate hepatocellular injury in ischemia-stressed murine livers.

Conclusion: These findings identify the Ikaros-SIRT1 axis as a novel mechanistic biomarker of pyroptosis and a putative checkpoint regulator of homeostasis in response to acute hepatic stress/injury in mouse and human livers.

Lay Summary: This report describes how crosstalk between Ikaros and SIRT1, two major transcriptional regulators, influence acute hepatic inflammation in murine models of liver ischemia-reperfusion injury and liver transplant recipients. We show that the myeloid Ikaros-SIRT1 axis regulates inflammasome-pyroptotic cell death and hepatocellular damage in stressed livers. Thus, the Ikaros-SIRT1 axis may serve as a novel checkpoint regulator that is required for homeostasis in response to acute liver injury in mice and humans.
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http://dx.doi.org/10.1016/j.jhep.2021.11.026DOI Listing
December 2021

Liver ischaemia-reperfusion injury: a new understanding of the role of innate immunity.

Nat Rev Gastroenterol Hepatol 2021 Nov 26. Epub 2021 Nov 26.

The Dumont-UCLA Transplantation Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California, Los Angeles, CA, USA.

Liver ischaemia-reperfusion injury (LIRI), a local sterile inflammatory response driven by innate immunity, is one of the primary causes of early organ dysfunction and failure after liver transplantation. Cellular damage resulting from LIRI is an important risk factor not only for graft dysfunction but also for acute and even chronic rejection and exacerbates the shortage of donor organs for life-saving liver transplantation. Hepatocytes, liver sinusoidal endothelial cells and Kupffer cells, along with extrahepatic monocyte-derived macrophages, neutrophils and platelets, are all involved in LIRI. However, the mechanisms underlying the responses of these cells in the acute phase of LIRI and how these responses are orchestrated to control and resolve inflammation and achieve homeostatic tissue repair are not well understood. Technological advances allow the tracking of cells to better appreciate the role of hepatic macrophages and platelets (such as their origin and immunomodulatory and tissue-remodelling functions) and hepatic neutrophils (such as their selective recruitment, anti-inflammatory and tissue-repairing functions, and formation of extracellular traps and reverse migration) in LIRI. In this Review, we summarize the role of macrophages, platelets and neutrophils in LIRI, highlight unanswered questions, and discuss prospects for innovative therapeutic regimens against LIRI in transplant recipients.
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http://dx.doi.org/10.1038/s41575-021-00549-8DOI Listing
November 2021

Successful En Bloc Resection of Locally Advanced Pancreatic Tail Cancer with Colonic Perforation Following Neoadjuvant Chemotherapy: A Case Report.

Am J Case Rep 2021 Oct 15;22:e933226. Epub 2021 Oct 15.

Department of Surgery, Kobe City Nishi-Kobe Medical Center, Kobe, Hyogo, Japan.

BACKGROUND Distal pancreatic cancers may be unresectable at the time of diagnosis because these cancers are asymptomatic and readily infiltrate neighboring organs. Radical resection of a pancreatic tail cancer with colonic perforation is rare. We describe successful resection of a locally advanced pancreatic tail cancer with colonic perforation using a multidisciplinary approach. CASE REPORT A 66-year-old man presented to our hospital with a chief concern of high fever. Abdominal computed tomography revealed a pancreatic tail tumor infiltrating the neighboring organs and causing colonic obstruction with perforation, which resulted in an intra-abdominal abscess. Colonoscopy revealed obstruction of the descending colon by extramural invasion. Laboratory tests showed high tumor marker concentrations (carcinoembryonic antigen, 11.6 ng/dL; pancreatic cancer-associated antigen-2, >1600 U/mL). We clinically diagnosed locally advanced pancreatic tail cancer with an intra-abdominal abscess caused by colonic perforation. First, we performed transverse colostomy and percutaneous drainage. We then started neoadjuvant chemotherapy with FOLFIRINOX for tumor shrinkage and prevention of distant metastases. The therapeutic effect was a partial response, and no distant metastases was found. We therefore performed radical surgery comprising distal pancreatectomy with partial resection of neighboring organs. Although pathological examination revealed a pancreatic tail tubular adenocarcinoma with direct invasion of the neighboring organs, R0 resection was achieved. The patient was discharged with no perioperative complications. Tegafur/gimeracil/oteracil potassium were administered as adjuvant chemotherapy. The patient remained recurrence-free for 19 months after surgery. CONCLUSIONS We achieved successful en bloc resection of a locally advanced distal pancreatic cancer with colonic perforation by using a multidisciplinary approach.
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http://dx.doi.org/10.12659/AJCR.933226DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8525901PMC
October 2021

Gallbladder cancer spreading into the aberrant cystic duct: First literature report.

Int J Surg Case Rep 2021 Nov 30;88:106443. Epub 2021 Sep 30.

Department of Surgery, Kobe City Nishi-Kobe Medical Center, Hyogo, Japan. Electronic address:

Introduction And Importance: Although variations from the standard anatomy of the extrahepatic bile ducts are common, duplication of the cystic duct draining a single gallbladder is an extremely rare variant. We herein describe the first report of gallbladder cancer spreading into the aberrant cystic duct.

Case Presentation: A 60-year-old female presented with upper abdominal pain, and she was diagnosed with gallbladder cancer. Intraoperatively, she was found to have a duplicated cystic duct draining a single gallbladder, and her cancer had spread into the aberrant cystic duct entering the anterior right hepatic duct. Right hepatectomy with extrahepatic bile duct resection was performed to achieve R0 resection.

Clinical Discussion: In the English literature, 28 cases of duplicated cystic duct draining a single gallbladder have been reported. However, no cases of gallbladder cancer have been described in these previous reports.

Conclusion: We report the first case of gallbladder cancer spreading into the aberrant cystic duct. To perform an oncologically adequate operation, exact assessment of the biliary tree is essential not only preoperatively but also intraoperatively.
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http://dx.doi.org/10.1016/j.ijscr.2021.106443DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8517158PMC
November 2021

Donor Hepatic Occult Collagen Deposition Predisposes to Peritransplant Stress and Impacts Human Liver Transplantation.

Hepatology 2021 11 30;74(5):2759-2773. Epub 2021 Aug 30.

The Dumont-UCLA Transplantation Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California, Los Angeles, CA.

Background And Aims: Environmentally triggered chronic liver inflammation can cause collagen deposits, whereas early stages of fibrosis without any specific symptoms could hardly be detectable. We hypothesized that some of the human donor grafts in clinical liver transplantation (LT) might possess unrecognizable fibrosis, affecting their susceptibility to LT-induced stress and hepatocellular damage. This retrospective study aimed to assess the impact of occult hepatic fibrosis on clinical LT outcomes.

Approach And Results: Human (194) donor liver biopsies were stained for collagen with Sirius red, and positive areas (Sirius red-positive area; SRA) were measured. The body mass index, aspartate aminotransferase/alanine aminotransferase ratio, diabetes score was calculated using 962 cases of the donor data at the procurement. LT outcomes, including ischemia-reperfusion injury (IRI), early allograft dysfunction (EAD), and survival rates, were analyzed according to SRA and BARD scores. With the median SRA in 194 grafts of 9.4%, grafts were classified into low-SRA (<15%; n = 140) and high-SRA (≥15%; n = 54) groups. Grafts with high SRA suffered from higher rates of IRI and EAD (P < 0.05) as compared to those with low SRA. Interestingly, high SRA was identified as an independent risk factor for EAD and positively correlated with the donor BARD score. When comparing low-BARD (n = 692) with high-BARD (n = 270) grafts in the same period, those with high BARD showed significantly higher post-LT transaminase levels and higher rates of IRI and EAD.

Conclusions: These findings from the largest clinical study cohort to date document the essential role of occult collagen deposition in donor livers on LT outcomes. High-SRA and donor BARD scores correlated with an increased incidence of hepatic IRI and EAD in LT recipients. This study provides the rationale for in-depth and prospective assessment of occult fibrosis for refined personalized LT management.
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http://dx.doi.org/10.1002/hep.32030DOI Listing
November 2021

Ischemia-reperfusion Injury in Allogeneic Liver Transplantation: A Role of CD4 T Cells in Early Allograft Injury.

Transplantation 2021 09;105(9):1989-1997

Department of Surgery, Division of Liver and Pancreas Transplantation, Dumont-UCLA Transplant Center, University of California, Los Angeles, CA.

Background: A major discrepancy between clinical and most experimental settings of liver ischemia-reperfusion injury (IRI) is the allogenicity.

Methods: In the current study, we first established a murine model of allogeneic orthotopic liver transplantation with extended cold ischemia time (18 h). Roles of CD4 T cells in the pathogenesis of IRI in liver allografts were determined using a depleting anti-CD4 antibody. The clinical relevance of CD4 as a marker of liver IRI was analyzed retrospectively in 55 liver transplant patients.

Results: CD4 depletion in both donors and recipients resulted in the most effective protection of liver allografts from IRI, as measured by serum transaminase levels and liver histology. CD4 depletion inhibited IR-induced intragraft neutrophil/macrophage infiltration and proinflammatory gene expressions. Quantitative reverse-transcriptase polymerase chain reaction analysis of human liver biopsies (2 h postreperfusion) revealed that posttransplant, rather than pretransplant, CD4 transcript levels correlated positively with proinflammatory gene expression profile. When we divided patients into subgroups according to intragraft CD4 levels, the high CD4 cohort developed a more severe hepatocellular damage than that with low CD4 levels.

Conclusions: CD4 T cells play a key pathogenic role in IRI of allogeneic liver transplants, and intragraft CD4 levels in the early postreperfusion phase may serve as a potential biomarker and therapeutic target to ameliorate liver IRI and improve orthotopic liver transplantation outcomes.
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http://dx.doi.org/10.1097/TP.0000000000003488DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8046839PMC
September 2021

Conversion to complete resection with mFOLFOX6 with bevacizumab or cetuximab based on K-RAS status for unresectable colorectal liver metastasis (BECK study): Long-term results of survival.

J Hepatobiliary Pancreat Sci 2020 Aug 9;27(8):496-509. Epub 2020 Jun 9.

Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

Background/purpose: To investigate the long-term outcome and entire treatment course of patients with technically unresectable CRLM who underwent conversion hepatectomy and to examine factors associated with conversion to hepatectomy.

Methods: Recurrence and survival data with long-term follow-up were analyzed in the cohort of a multi-institutional phase II trial for technically unresectable colorectal liver metastases (the BECK study).

Results: A total of 22/12 patients with K-RAS wild-type/mutant tumors were treated with mFOLFOX6 + cetuximab/bevacizumab. The conversion R0/1 hepatectomy rate was significantly higher in left-sided primary tumors than in right-sided tumors (75.0% vs 30.0%, P = .022). The median follow-up was 72.6 months. The 5-year overall survival (OS) rate in the entire cohort was 48.1%. In patients who underwent R0/1 hepatectomy (n = 21), the 5-year RFS rate and OS rate were 19.1% and 66.3%, respectively. At the final follow-up, seven patients had no evidence of disease, five were alive with disease, and 20 had died from their original cancer. All 16 patients who achieved 5-year survival underwent conversion hepatectomy, and 11 of them underwent further resection for other recurrences (median: 2, range: 1-4).

Conclusions: Conversion hepatectomy achieved a similar long-term survival to the results of previous studies in initially resectable patients, although many of them experienced several post-hepatectomy recurrences. Left-sided primary was found to be the predictor for conversion hepatectomy.
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http://dx.doi.org/10.1002/jhbp.747DOI Listing
August 2020

The Impact of Biliary Reconstruction Methods on Small Partial Liver Grafts.

Transplant Direct 2020 Feb 13;6(2):e523. Epub 2020 Jan 13.

Department of Surgery, Division of Hepato-Biliary-Pancreatic Surgery and Transplantation, Kyoto University Graduate School of Medicine, Kyoto, Japan.

Graft recipient weight ratios are lower in adult-to-adult living-donor liver transplantation than in adult-to-adult deceased-donor liver transplantation. Rapid liver regeneration is essential for increased recipient survival rates in adult-to-adult living-donor liver transplantation. However, the influence of biliary reconstruction methods, including choledocho-choledochostomy and choledocho-jejunostomy, on small partial liver grafts remains unknown. Herein, we investigate the impact of these biliary reconstruction methods on small partial liver grafts.

Methods: Male Lewis rats underwent isogenic arterialized 30% partial liver transplantation with small partial grafts, either via choledocho-jejunostomy or choledocho-choledochostomy.

Results: The 7-day survival rates of the choledocho-choledochostomy and choledocho-jejunostomy groups were 100% and 50%, respectively ( = 0.011). Choledocho-jejunostomy provoked reflux cholangitis, as confirmed by neutrophil infiltration around the bile ducts; suppressed and delayed liver regeneration in grafts, as confirmed by significant increases in intrahepatic interleukin-1β level, significant decreases in the graft weight increase ratios, hepatocyte proliferation, and intrahepatic mRNA expression of vascular endothelial growth factor; and induced graft dysfunction, as confirmed by the presence of massive ascites, significantly decreased bile production, and prolonged elevation of total bilirubin, aspartate aminotransferase, and alanine aminotransferase.

Conclusions: Choledocho-jejunostomy predisposed grafts to cholangitis, impaired liver regeneration, and aggravated animal survival, suggesting that choledocho-choledochostomy may be preferable over choledocho-jejunostomy in adult-to-adult living-donor liver transplantation.
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http://dx.doi.org/10.1097/TXD.0000000000000966DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7004631PMC
February 2020

Heme Oxygenase-1 in liver transplant ischemia-reperfusion injury: From bench-to-bedside.

Free Radic Biol Med 2020 09 19;157:75-82. Epub 2020 Feb 19.

Dumont-UCLA Transplantation Center, Department of Surgery, Division of Liver and Pancreas Transplantation, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA. Electronic address:

Hepatic ischemia-reperfusion injury (IRI), a major risk factor for early allograft dysfunction (EAD) and acute or chronic graft rejection, contributes to donor organ shortage for life-saving orthotopic liver transplantation (OLT). The graft injury caused by local ischemia (warm and/or cold) leads to parenchymal cell death and release of danger-associated molecular patterns (DAMPs), followed by reperfusion-triggered production of reactive oxygen species (ROS), activation of inflammatory cells, hepatocellular damage and ultimate organ failure. Heme oxygenase 1 (HO-1), a heat shock protein-32 induced under IR-stress, is an essential component of the cytoprotective mechanism in stressed livers. HO-1 regulates anti-inflammatory responses and may be crucial in the pathogenesis of chronic diseases, such as arteriosclerosis, hypertension, diabetes and steatosis. An emerging area of study is macrophage-derived HO-1 and its pivotal intrahepatic homeostatic function played in IRI-OLT. Indeed, ectopic hepatic HO-1 overexpression activates intracellular SIRT1/autophagy axis to serve as a key cellular self-defense mechanism in both mouse and human OLT recipients. Recent translational studies in rodents and human liver transplant patients provide novel insights into HO-1 mediated cytoprotection against sterile hepatic inflammation. In this review, we summarize the current bench-to-bedside knowledge on HO-1 molecular signaling and discuss their future therapeutic potential to mitigate IRI in OLT.
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http://dx.doi.org/10.1016/j.freeradbiomed.2020.02.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7434658PMC
September 2020

Hepatic CEACAM1 expression indicates donor liver quality and prevents early transplantation injury.

J Clin Invest 2020 05;130(5):2689-2704

Department of Surgery, Division of Liver and Pancreas Transplantation, Dumont-UCLA Liver Transplant Center.

Although CEACAM1 (CC1) glycoprotein resides at the interface of immune liver injury and metabolic homeostasis, its role in orthotopic liver transplantation (OLT) remains elusive. We aimed to determine whether/how CEACAM1 signaling may affect hepatic ischemia-reperfusion injury (IRI) and OLT outcomes. In the mouse, donor liver CC1 null mutation augmented IRI-OLT (CC1-KO→WT) by enhancing ROS expression and HMGB1 translocation during cold storage, data supported by in vitro studies where hepatic flush from CC1-deficient livers enhanced macrophage activation in bone marrow-derived macrophage cultures. Although hepatic CC1 deficiency augmented cold stress-triggered ASK1/p-p38 upregulation, adjunctive ASK1 inhibition alleviated IRI and improved OLT survival by suppressing p-p38 upregulation, ROS induction, and HMGB1 translocation (CC1-KO→WT), whereas ASK1 silencing (siRNA) promoted cytoprotection in cold-stressed and damage-prone CC1-deficient hepatocyte cultures. Consistent with mouse data, CEACAM1 expression in 60 human donor liver biopsies correlated negatively with activation of the ASK1/p-p38 axis, whereas low CC1 levels associated with increased ROS and HMGB1 translocation, enhanced innate and adaptive immune responses, and inferior early OLT function. Notably, reduced donor liver CEACAM1 expression was identified as one of the independent predictors for early allograft dysfunction (EAD) in human OLT patients. Thus, as a checkpoint regulator of IR stress and sterile inflammation, CEACAM1 may be considered as a denominator of donor hepatic tissue quality, and a target for therapeutic modulation in OLT recipients.
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http://dx.doi.org/10.1172/JCI133142DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7190917PMC
May 2020

Therapeutic targets for liver regeneration after acute severe injury: a preclinical overview.

Expert Opin Ther Targets 2020 01 10;24(1):13-24. Epub 2020 Jan 10.

The Dumont-UCLA Transplantation Center, Department of Surgery, Division of Liver and Pancreas Transplantation, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.

: Liver transplantation is the only viable treatment with a proven survival benefit for acute liver failure (ALF). Donor organ shortage is, however, a major hurdle; hence, alternative approaches that enable liver regeneration and target acute severe hepatocellular damage are necessary.: This article sheds light on therapeutic targets for liver regeneration and considers their therapeutic potential. ALF following extensive hepatocyte damage and small-for-size syndrome (SFSS) are illuminated for the reader while the molecular mechanisms of liver regeneration are assessed in accordance with relevant therapeutic strategies. Furthermore, liver background parameters and predictive biomarkers that might associate with liver regeneration are reviewed.: There are established and novel experimental strategies for liver regeneration to prevent ALF resulting from SFSS. Granulocyte-colony stimulating factor (G-CSF) is a promising agent targeting liver regeneration after acute severe injury. Autophagy and hepatocyte senescence represent attractive new targets for liver regeneration in acute severe hepatic injury. Liver support strategies, including tissue engineering, constitute novel regenerative means; the success of this is dependent on stem cell research advances. However, there is no firm clinical evidence that these supportive strategies may alleviate hepatocellular damage until liver transplantation becomes available or successful self-liver regeneration occurs.
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http://dx.doi.org/10.1080/14728222.2020.1712361DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7050477PMC
January 2020

Human Antigen R (HuR): A Regulator of Heme Oxygenase-1 Cytoprotection in Mouse and Human Liver Transplant Injury.

Hepatology 2020 09 17;72(3):1056-1072. Epub 2020 Jul 17.

The Dumont-UCLA Transplantation Center, Department of Surgery, Division of Liver and Pancreas Transplantation, David Geffen School of Medicine at UCLA, Los Angeles, CA.

Background And Aims: Ischemia-reperfusion injury (IRI) represents a risk factor in liver transplantation (LT). We have shown that overexpression of heme oxygenase-1 (HO-1) mitigates hepatic IRI in LT recipients. Here, we hypothesized that human antigen R (HuR), the stabilizer of adenylate-uridylate (AU)-rich mRNAs, is required for hepatoprotection in LT.

Approach And Results: In an experimental arm, HuR/HO-1 protein expression was correlated with hepatic IRI phenotype. In an in vitro inflammation mimic model of hepatic warm IRI, induction of HuR/HO-1 and cytoplasmic localization following cytokine preconditioning were detected in primary hepatocyte cultures, whereas HuR silencing caused negative regulation of HO-1, followed by enhanced cytotoxicity. Using the HuR-inhibitor, we showed that HuR likely regulates HO-1 through its 3' untranslated region and causes neutrophil activation (CD69+/lymphocyte antigen 6 complex locus G [Ly6-G]). HuR silencing in bone marrow-derived macrophages decreased HO-1 expression, leading to the induction of proinflammatory cytokines/chemokines. RNA sequencing of HuR silenced transcripts under in vitro warm IRI revealed regulation of genes thymus cell antigen 1 (THY1), aconitate decarboxylase 1 (ACOD1), and Prostaglandin E Synthase (PTGES). HuR, but not hypoxia-inducible protein alpha, positively regulated HO-1 in warm, but not cold, hypoxia/reoxygenation conditions. HuR modulated HO-1 in primary hepatocytes, neutrophils, and macrophages under reperfusion. Adjunctive inhibition of HuR diminished microtubule-associated proteins 1A/1B light chain 3B (LC3B), a marker for autophagosome, under HO-1 regulation, suggesting a cytoprotective mechanism in hepatic IR. In a clinical arm, hepatic biopsies from 51 patients with LT were analyzed at 2 hours after reperfusion. Graft HuR expression was negatively correlated with macrophage (CD80/CD86) and neutrophil (Cathepsin G) markers. Hepatic IRI increased HuR/HO-1 expression and inflammatory genes. High HuR-expressing liver grafts showed lower serum alanine aminotransferase/serum aspartate aminotransferase levels and improved LT survival.

Conclusions: This translational study identifies HuR as a regulator of HO-1-mediated cytoprotection in sterile liver inflammation and a biomarker of ischemic stress resistance in LT.
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http://dx.doi.org/10.1002/hep.31093DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8330638PMC
September 2020

The Evolving Role of Neutrophils in Liver Transplant Ischemia-Reperfusion Injury.

Curr Transplant Rep 2019 29;6(1):78-89. Epub 2019 Jan 29.

The Dumont-UCLA Transplant Center, Department of Surgery, Division of Liver and Pancreas Transplantation, David Geffen School of Medicine at University of California, Los Angeles, CA 90095.

Purpose Of Review: Hepatic ischemia-reperfusion injury (IRI), an inevitable event during liver transplantation, represents a major risk factor for the primary graft dysfunction as well as the development of acute and chronic rejection. Neutrophils, along macrophages are pivotal in the innate immune-driven liver IRI, whereas the effective neutrophil targeting therapies remain to be established. In this review, we summarize progress in our appreciation of the neutrophil biology and discuss neutrophil-based therapeutic perspectives.

Recent Findings: New technological advances enable to accurately track neutrophil movements and help to understand molecular mechanisms in neutrophil function, such as selective recruitment to IR-stressed tissue, formation of neutrophil extracellular traps, or reverse migration into circulation. In addition to pro-inflammatory and tissue-destructive functions, immune regulatory and tissue-repairing phenotype associated with distinct neutrophil subsets, have been identified.

Summary: Newly recognized and therapeutically attractive neutrophil characteristics warrant comprehensive preclinical and clinical attention to target IRI in transplant recipients.
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http://dx.doi.org/10.1007/s40472-019-0230-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6786799PMC
January 2019

Innate immunity in ischemia-reperfusion injury and graft rejection.

Curr Opin Organ Transplant 2019 12;24(6):687-693

Division of Liver and Pancreas Transplantation, Department of Surgery, The Dumont-UCLA Transplantation Center, David Geffen School of Medicine at University of California, Los Angeles, California, USA.

Purpose Of Review: Although organ transplantation has become the standard life-saving strategy for patients with end-stage organ failure and those with malignancies, effective and safe therapeutic strategies to combat allograft loss remain to be established. With the emerging evidence suggesting the critical role of innate immunity in the mechanism of allograft injury, we summarize the latest understanding of macrophage-neutrophil cross-communication and discuss therapeutic prospects of their targeting in transplant recipients.

Recent Findings: Macrophages and neutrophils contribute to the pathogenesis of early peritransplant ischemia-reperfusion injury and subsequent allograft rejection immune cascade, primarily by exacerbating inflammatory response and tissue damage. Noteworthy, recent advances enabled to elucidate multifaceted functions of innate immune cells, which are not only deleterious but may also prove graft-protective. Indeed, the efficacy of macrophage polarizing regimens or macrophage-targeted migration have been recognized to create graft-protective local environment. Moreover, novel molecular mechanisms in the neutrophil function have been identified, such as neutrophil extracellular traps, tissue-repairing capability, crosstalk with macrophages and T cells as well as reverse migration into the circulation.

Summary: As efficient strategies to manage allograft rejection and improve transplant outcomes are lacking, newly discovered, and therapeutically attractive innate immune cell functions warrant comprehensive preclinical and clinical attention.
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http://dx.doi.org/10.1097/MOT.0000000000000709DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7428085PMC
December 2019

Impact of Rifaximin Therapy on Ischemia/Reperfusion Injury in Liver Transplantation: A Propensity Score-Matched Analysis.

Liver Transpl 2019 12 4;25(12):1778-1789. Epub 2019 Nov 4.

The Dumont-UCLA Transplantation Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.

Intestinal microbiota is thought to play an important role in hepatic ischemia/reperfusion injury (IRI) after liver transplantation (LT). Rifaximin, a nonabsorbable antibiotic used to treat encephalopathy, exhibits antibacterial activity within the gut. We report the first study examining the impact of pre-LT rifaximin use on reducing hepatic IRI and inflammatory cell infiltration after LT. This retrospective single-center study included adult LT recipients from January 2013 through June 2016. Patients were divided into 2 groups based on duration of rifaximin use before LT: rifaximin group (≥28 days) and control group (none or <28 days). Patients receiving other antibiotics within 28 days of LT and re-LTs were excluded. Outcomes and messenger RNA (mRNA) expression in the graft were compared by 1:1 propensity score-matching and multivariate analyses. On 1:1 matching (n = 39/group), rifaximin patients had lower postoperative serum transaminase levels and lower early allograft dysfunction (EAD; 10.3% versus 33.3%; P = 0.014). Of the matched patients, 8 patients (n = 4/group) had postreperfusion liver biopsies (approximately 2 hours after reperfusion) available for mRNA analysis. Hepatic expression of CD86 (macrophage marker) and cathepsin G (neutrophil marker) was significantly lower in rifaximin patients than controls (P < 0.05). The multivariate analysis included 458 patients. Rifaximin treatment <28 days was identified as an independent risk factor EAD in all patients and those with high Model for End-Stage Liver Disease (MELD) score (MELD ≥35; n = 230). In conclusion, the propensity score-matched and multivariate analyses suggest a therapeutic role of rifaximin in reducing EAD. Pre-LT rifaximin administration exerted a protective function against early liver injury, potentially by suppressing inflammatory cell activation in the graft.
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http://dx.doi.org/10.1002/lt.25633DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6887108PMC
December 2019

Antibiotic pretreatment alleviates liver transplant damage in mice and humans.

J Clin Invest 2019 07 22;129(8):3420-3434. Epub 2019 Jul 22.

Dumont-UCLA Transplantation Center, Department of Surgery, Division of Liver and Pancreas Transplantation, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.

Although modifications of gut microbiota with antibiotics (Abx) influence mouse skin and cardiac allografts, its role in orthotopic liver transplantation (OLT) remains unknown. We aimed to determine whether and how recipient Abx pretreatment may affect hepatic ischemia-reperfusion injury (IRI) and OLT outcomes. Mice (C57BL/6) with or without Abx treatment (10 days) were transplanted with allogeneic (BALB/c) cold-stored (18 hours) livers, followed by liver and blood sampling (6 hours). We divided 264 human OLT recipients on the basis of duration of pre-OLT Abx treatment into control (Abx-free/Abx <10 days; n = 108) and Abx treatment (Abx ≥10days; n = 156) groups; OLT biopsy (Bx) samples were collected 2 hours after OLT (n = 52). Abx in mice mitigated IRI-stressed OLT (IRI-OLT), decreased CCAAT/enhancer-binding protein homologous protein (CHOP) (endoplasmic reticulum [ER] stress), enhanced LC3B (autophagy), and inhibited inflammation, whereas it increased serum prostaglandin E2 (PGE2) and hepatic PGE2 receptor 4 (EP4) expression. PGE2 increased EP4, suppressed CHOP, and induced autophagosome formation in hepatocyte cultures in an EP4-dependent manner. An EP4 antagonist restored CHOP, suppressed LC3B, and recreated IRI-OLT. Remarkably, human recipients of Abx treatment plus OLT (Abx-OLT), despite severe pretransplantation clinical acuity, had higher EP4 and LC3B levels but lower CHOP levels, which coincided with improved hepatocellular function (serum aspartate aminotransferase/serum aspartate aminotransferase [sALT/sAST]) and a decreased incidence of early allograft dysfunction (EAD). Multivariate analysis identified "Abx-free/Abx <10 days" as a predictive factor of EAD. This study documents the benefits of Abx pretreatment in liver transplant recipients, identifies ER stress and autophagy regulation by the PGE2/EP4 axis as a homeostatic underpinning, and points to the microbiome as a therapeutic target in OLT.
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http://dx.doi.org/10.1172/JCI127550DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6668671PMC
July 2019

Heme Oxygenase-1 dictates innate - adaptive immune phenotype in human liver transplantation.

Arch Biochem Biophys 2019 08 9;671:162-166. Epub 2019 Jul 9.

The Dumont-UCLA Transplantation Center, Department of Surgery, Division of Liver and Pancreas Transplantation, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA. Electronic address:

Liver transplantation (LT) has become the standard of care for patients with end-stage liver disease and those with hepatic malignancies, while adaptive immune-dominated graft rejection remains a major challenge. Despite potent anti-inflammatory and cytoprotective functions of heme oxygenase-1 (HO-1) overexpression upon innate immune-driven hepatic ischemia reperfusion injury, its role in adaptive immune cell-driven responses remains to be elucidated. We analyzed human biopsies from LT recipients (n = 55) to determine putative association between HO-1 levels and adaptive/co-stimulatory gene expression programs in LT. HO-1 expression negatively correlated with innate (CD68, Cathepsin G, TLR4, CXCL10), adaptive (CD4, CD8, IL17) and co-stimulatory (CD28, CD80, CD86) molecules at the graft site. LT recipients with high HO-1 expression showed a trend towards improved overall survival. By demonstrating the association between graft HO-1 levels and adaptive/co-stimulatory gene programs, our study provides important insights to the role of HO-1 signaling in LT patients.
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http://dx.doi.org/10.1016/j.abb.2019.07.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6688971PMC
August 2019

Cross-examination of Oxidative Stress-induced DNA Glycosylase OGG1, a Mediator of Innate Inflammation.

Transplantation 2019 06;103(6):1071-1073

Division of Liver and Pancreas Transplantation, Department of Surgery, The Dumont-UCLA Transplant Center, David Geffen School of Medicine at UCLA, Los Angeles, CA.

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http://dx.doi.org/10.1097/TP.0000000000002638DOI Listing
June 2019

Relaxin in liver transplantation: A personal perspective.

Mol Cell Endocrinol 2019 05 3;487:75-79. Epub 2019 Mar 3.

The Dumont-UCLA Transplant Center, Department of Surgery, Division of Liver and Pancreas Transplantation, David Geffen School of Medicine at University of California, Los Angeles, CA, 90095, USA. Electronic address:

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http://dx.doi.org/10.1016/j.mce.2019.02.022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7417179PMC
May 2019

Relaxin in liver transplantation: A personal perspective.

Mol Cell Endocrinol 2019 02 11;482:57-61. Epub 2018 Dec 11.

The Dumont-UCLA Transplant Center, Department of Surgery, Division of Liver and Pancreas Transplantation, David Geffen School of Medicine at University of California, Los Angeles, CA, 90095, USA. Electronic address:

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http://dx.doi.org/10.1016/j.mce.2018.12.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7427537PMC
February 2019

Myeloid HO-1 modulates macrophage polarization and protects against ischemia-reperfusion injury.

JCI Insight 2018 10 4;3(19). Epub 2018 Oct 4.

Department of Medicine, Division of Cardiology, and.

Macrophages polarize into heterogeneous proinflammatory M1 and antiinflammatory M2 subtypes. Heme oxygenase 1 (HO-1) protects against inflammatory processes such as ischemia-reperfusion injury (IRI), organ transplantation, and atherosclerosis. To test our hypothesis that HO-1 regulates macrophage polarization and protects against IRI, we generated myeloid-specific HO-1-knockout (mHO-1-KO) and -transgenic (mHO-1-Tg) mice, with deletion or overexpression of HO-1, in various macrophage populations. Bone marrow-derived macrophages (BMDMs) from mHO-1-KO mice, treated with M1-inducing LPS or M2-inducing IL-4, exhibited increased mRNA expression of M1 (CXCL10, IL-1β, MCP1) and decreased expression of M2 (Arg1 and CD163) markers as compared with controls, while BMDMs from mHO-1-Tg mice displayed the opposite. A similar pattern was observed in the hepatic M1/M2 expression profile in a mouse model of liver IRI. mHO-1-KO mice displayed increased hepatocellular damage, serum AST/ALT levels, Suzuki's histological score of liver IRI, and neutrophil and macrophage infiltration, while mHO-1-Tg mice exhibited the opposite. In human liver transplant biopsies, subjects with higher HO-1 levels showed lower expression of M1 markers together with decreased hepatocellular damage and improved outcomes. In conclusion, myeloid HO-1 expression modulates macrophage polarization, and protects against liver IRI, at least in part by favoring an M2 phenotype.
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http://dx.doi.org/10.1172/jci.insight.120596DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6237471PMC
October 2018

Recipient HO-1 inducibility is essential for posttransplant hepatic HO-1 expression and graft protection: From bench-to-bedside.

Am J Transplant 2019 02 24;19(2):356-367. Epub 2018 Aug 24.

Division of Liver and Pancreas Transplantation, Department of Surgery, The Dumont-UCLA Transplantation Center, David Geffen School of Medicine at University of California, Los Angeles, CA, USA.

By documenting potent antioxidative and anti-inflammatory functions, preclinical studies encourage heme oxygenase-1 (HO-1)-inducing regimens in clinical orthotopic liver transplantation (OLT). We aimed to determine the importance of recipient-derived HO-1 in murine and human OLTs. Hepatic biopsies from 51 OLT patients were screened for HO-1 expression (Western blots) prior to put-in (basal) and post reperfusion (stressed) and correlated with the hepatocellular function. In parallel, livers from HO-1 proficient mice (WT; C57/BL6), subjected to ex vivo cold storage (18 hour), were transplanted to syngeneic myeloid HO-1 deficient (mHO-1 KO) or FLOX (control) hosts, and sampled postreperfusion (6 hour). In human OLT, posttransplant but not pretransplant HO-1 expression correlated negatively with ALT levels (P = .0178). High posttransplant but not pretransplant HO-1 expression trended with improved OLT survival. Compared with controls, livers transplanted into mHO-1 KO recipient mice had decreased HO-1 levels, exacerbated hepatic damage/frequency of TUNEL+ cells, increased mRNA levels coding for TNFα/CXCL1/CXCL2/CXCL10, higher frequency of Ly6G+/4HN+ neutrophils; and enhanced MPO activity. Peritoneal neutrophils from mHO-1 KO mice exhibited higher CellRox+ ratio and increased TNFα/CXCL1/CXCL2/CXCL10 expression. By demonstrating the importance of posttransplant recipient HO-1 phenotype in hepatic macrophage/neutrophil regulation and function, this translational study identifies recipient HO-1 inducibility as a novel biomarker of ischemic stress resistance in OLT.
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http://dx.doi.org/10.1111/ajt.15043DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6349504PMC
February 2019

Reply to: "Protective effects of heme oxygenase 1 during ischemia-reperfusion injury: Hepatocytes or non parenchymal cells?"

J Hepatol 2018 09 2;69(3):753-755. Epub 2018 Jun 2.

The Dumont-UCLA Transplantation Center, Department of Surgery, Division of Liver and Pancreas Transplantation, University of California, Los Angeles, CA 90095, United States. Electronic address:

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http://dx.doi.org/10.1016/j.jhep.2018.05.029DOI Listing
September 2018

Serelaxin induces Notch1 signaling and alleviates hepatocellular damage in orthotopic liver transplantation.

Am J Transplant 2018 07 23;18(7):1755-1763. Epub 2018 Mar 23.

Division of Liver and Pancreas Transplantation, Department of Surgery, The Dumont-UCLA Transplant Center, David Geffen School of Medicine at University of California, Los Angeles, CA, USA.

Liver ischemia-reperfusion injury (IRI) represents a risk factor for early graft dysfunction and an obstacle to expanding donor pool in orthotopic liver transplantation (OLT). We have reported on the crucial role of macrophage Notch1 signaling in mouse warm hepatic IRI model. However, its clinical relevance or therapeutic potential remain unknown. Here, we used Serelaxin (SER), to verify Notch1 induction and putative hepatoprotective function in ischemia-reperfusion-stressed OLT. C57BL/6 mouse livers subjected to extended (18-hour) cold storage were transplanted to syngeneic recipients. SER treatment at reperfusion ameliorated IRI, improved post-OLT survival, decreased neutrophil/macrophage infiltration, and suppressed proinflammatory cytokine programs, while simultaneously increasing Notch intracellular domain (NICD) and hairy and enhancer of split 1 (Hes1) target genes. In bone marrow-derived macrophage cultures, SER suppressed proinflammatory while enhancing antiinflammatory gene expression concomitantly with increased NICD and Hes1. Hepatic biopsies from 21 adult primary liver transplant patients (2 hours postreperfusion) were divided into low-NICD (n = 11) and high-NICD (n = 10) expression groups (western blots). Consistent with our murine findings, human livers characterized by high NICD were relatively IRI resistant, as shown by serum alanine aminotransferase (ALT) levels at day 1 post-OLT. Our study documents the efficacy of SER-Notch1 signaling in mouse OLT and highlights the protective function of Notch1 in liver transplant patients.
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http://dx.doi.org/10.1111/ajt.14706DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6035063PMC
July 2018

Recombinant relaxin protects liver transplants from ischemia damage by hepatocyte glucocorticoid receptor: From bench-to-bedside.

Hepatology 2018 07 10;68(1):258-273. Epub 2018 May 10.

The Dumont-UCLA Transplant Center, Department of Surgery, Division of Liver and Pancreas Transplantation, David Geffen School of Medicine at University of California, Los Angeles, CA.

Hepatic ischemia-reperfusion injury (IRI) represents a major risk factor of early graft dysfunction and acute/chronic rejection as well as a key obstacle to expanding the donor pool in orthotopic liver transplantation (OLT). Although glucocorticoid receptor (GR) signaling may enhance cytoprotective programs, clinical use of glucocorticoid is limited because of adverse effects, whereas clinical relevance of GR-facilitated cytoprotection in OLT remains unknown. We aimed to evaluate the significance of hepatic GR in clinical OLT and verify the impact of recombinant human relaxin (rhRLX), which may function as a GR agonist in a tissue/disease-specific manner. Fifty-one OLT patients were recruited under an institutional research board (IRB) protocol. Liver biopsies were collected after cold storage (presurgery) and 2 hours postreperfusion (before abdominal closure), followed by western blotting-assisted hepatic analyses. Forty-three percent of OLTs failed to increase GR perioperatively under surgical stress. Post-/pre-GR ratios at postoperative day 1 correlated negatively with serum aspartate aminotransferase (AST)/cleaved caspase-3 and positively with B-cell lymphoma-extra large (Bcl-xL)/B-cell lymphoma 2 (Bcl-2) levels. In a murine OLT model with extended (18-hour) cold storage, treatment with rhRLX ameliorated ischemia-reperfusion (IR) damage and improved survival while up-regulating hepatocyte GR and Bcl-xL/Bcl-2 expression in OLT. rhRLX-induced GR suppressed hepatocyte high-mobility group box 1 (HMGB1) translocation/release, accompanied by decreased Toll-like receptor 4 (TLR4)/receptor for advanced glycation end products (RAGE), suppressed interleukin 1 beta (IL1β), chemokine (C-C motif) ligand 2 (CCL2), C-X-C motif chemokine (CXCL)10, tumor necrosis factor alpha (TNFα), CXCL1, and CXCL2 levels, and attenuated neutrophil/macrophage accumulation in OLT. Inhibition of GR in hepatocyte culture and in OLT diminished rhRLX-mediated cytoprotection.

Conclusion: This translational study underscores the role of rhRLX-GR signaling as a regulator of hepatocellular protection against IR stress in OLT. In the context of a recent phase III clinical trial demonstrating positive outcomes of rhRLX in patients with acute heart failure, studies on rhRLX for the management of IRI in OLT recipients are warranted. (Hepatology 2018;68:258-273).
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http://dx.doi.org/10.1002/hep.29787DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6033647PMC
July 2018

Heme oxygenase-1 regulates sirtuin-1-autophagy pathway in liver transplantation: From mouse to human.

Am J Transplant 2018 05 18;18(5):1110-1121. Epub 2017 Dec 18.

The Dumont-UCLA Transplant Center, Department of Surgery, Division of Liver and Pancreas Transplantation, University of California, Los Angeles, Los Angeles, CA, USA.

Liver ischemia-reperfusion injury (IRI) represents a major risk factor of early graft dysfunction and a key obstacle to expanding the donor pool in orthotopic liver transplantation (OLT). Although graft autophagy is essential for resistance against hepatic IRI, its significance in clinical OLT remains unknown. Despite recent data identifying heme oxygenase-1 (HO-1) as a putative autophagy inducer, its role in OLT and interactions with sirtuin-1 (SIRT1), a key autophagy regulator, have not been studied. We aimed to examine HO-1-mediated autophagy induction in human OLT and in a murine OLT model with extended (20 hours) cold storage, as well as to analyze the requirement for SIRT1 in autophagy regulation by HO-1. Fifty-one hepatic biopsy specimens from OLT patients were collected under an institutional review board protocol 2 hours after portal reperfusion, followed by Western blot analyses. High HO-1 levels correlated with well-preserved hepatocellular function and enhanced SIRT1/LC3B expression. In mice, HO-1 overexpression by genetically modified HO-1 macrophage therapy was accompanied by decreased OLT damage and increased SIRT1/LC3B expression, whereas adjunctive inhibition of SIRT1 signaling diminished HO-1-mediated hepatoprotection and autophagy induction. Our translational study confirms the clinical relevance of HO-1 cytoprotection and identifies SIRT1-mediated autophagy pathway as a new essential regulator of HO-1 function in IR-stressed OLT.
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http://dx.doi.org/10.1111/ajt.14586DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5910267PMC
May 2018

Macrophage heme oxygenase-1-SIRT1-p53 axis regulates sterile inflammation in liver ischemia-reperfusion injury.

J Hepatol 2017 12 23;67(6):1232-1242. Epub 2017 Aug 23.

The Dumont-UCLA Transplantation Center, Department of Surgery, Division of Liver and Pancreas Transplantation, David Geffen School of Medicine at University of California, Los Angeles, CA 90095, USA. Electronic address:

Background & Aims: Hepatic ischemia-reperfusion injury (IRI), characterized by exogenous antigen-independent local inflammation and hepatocellular death, represents a risk factor for acute and chronic rejection in liver transplantation. We aimed to investigate the molecular communication involved in the mechanism of liver IRI.

Methods: We analyzed human liver transplants, primary murine macrophage cell cultures and IR-stressed livers in myeloid-specific heme oxygenase-1 (HO-1) gene mutant mice, for anti-inflammatory and cytoprotective functions of macrophage-specific HO-1/SIRT1 (sirtuin 1)/p53 (tumor suppressor protein) signaling.

Results: Decreased HO-1 expression in human post-reperfusion liver transplant biopsies correlated with a deterioration in hepatocellular function (serum ALT; p<0.05) and inferior patient survival (p<0.05). In the low HO-1 liver transplant biopsy group, SIRT1/Arf (alternative reading frame)/p53/MDM2 (murine double minute 2) expression levels decreased (p<0.05) while cleaved caspase 3 and frequency of TUNEL+cells simultaneously increased (p<0.05). Immunofluorescence showed macrophages were the principal source of HO-1 in human and mouse IR-stressed livers. In vitro macrophage cultures revealed that HO-1 induction positively regulated SIRT1 signaling, whereas SIRT1-induced Arf inhibited ubiquitinating activity of MDM2 against p53, which in turn attenuated macrophage activation. In a murine model of hepatic warm IRI, myeloid-specific HO-1 deletion lacked SIRT1/p53, exacerbated liver inflammation and IR-hepatocellular death, whereas adjunctive SIRT1 activation restored p53 signaling and rescued livers from IR-damage.

Conclusion: This bench-to-bedside study identifies a new class of macrophages activated via the HO-1-SIRT1-p53 signaling axis in the mechanism of hepatic sterile inflammation. This mechanism could be a target for novel therapeutic strategies in liver transplant recipients.

Lay Summary: Post-transplant low macrophage HO-1 expression in human liver transplants correlates with reduced hepatocellular function and survival. HO-1 regulates macrophage activation via the SIRT1-p53 signaling network and regulates hepatocellular death in liver ischemia-reperfusion injury. Thus targeting this pathway in liver transplant recipients could be of therapeutic benefit.
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http://dx.doi.org/10.1016/j.jhep.2017.08.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5884687PMC
December 2017

Sirtuin 1 attenuates inflammation and hepatocellular damage in liver transplant ischemia/Reperfusion: From mouse to human.

Liver Transpl 2017 10;23(10):1282-1293

Dumont-UCLA Transplant Center, Department of Surgery, Division of Liver and Pancreas Transplantation, University of California, Los Angeles, Los Angeles, CA.

Hepatic ischemia/reperfusion injury (IRI), an inevitable antigen-independent inflammation response in cadaveric liver transplantation, correlates with poor early graft function, rejection episodes, and contributes to donor organ shortage. Sirtuin 1 (SIRT1) is a histone deacetylase that may regulate inflammatory cell activity and manage liver function in IRI, though its functional role and clinical relevance remains to be elucidated. We investigated the efficacy of SIRT1 activation in a murine liver IRI model and verified the concept of putative SIRT1-mediated hepatoprotection in clinical liver transplantation. In the experimental arm, mice were subjected to 90 minutes of liver partial warm ischemia followed by 6 hours of reperfusion with or without adjunctive SIRT1 activation in vivo (resveratrol [Res]). In parallel, bone marrow-derived macrophage (BMDM) or spleen lymphocyte cultures were treated with Res. In the clinical arm, liver biopsies from 21 adult primary liver transplant patients (2 hours after reperfusion) were divided into "low" (n = 11) versus "high" (n = 10) SIRT1 expression groups, assessed by Western blots. Treatment with Res attenuated murine liver IRI while up-regulating SIRT1, suppressing leukocyte infiltration, and decreasing proinflammatory cytokine programs. SIRT1 silencing (small interfering RNA) in BMDM cultures enhanced inflammatory cytokine programs, whereas addition of Res decreased proinflammatory response in a SIRT1-dependent manner. In addition, Res decreased interferon γ production in liver-infiltrating and spleen lymphocyte cultures. Human liver transplants with high SIRT1 levels showed improved hepatocellular function and superior survival (P = 0.04), accompanied by lower proinflammatory cytokine profile. In conclusion, our translational study is the first to identify SIRT1 as a regulator of hepatocellular function in human liver transplant recipients under ischemia/reperfusion stress. By targeting innate and adaptive immune activation, manipulation of SIRT1 signaling should be considered as a novel means to combat inflammation in liver transplantation. Liver Transplantation 23 1282-1293 2017 AASLD.
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http://dx.doi.org/10.1002/lt.24821DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5705033PMC
October 2017

Bruton Tyrosine Kinase Inhibition Attenuates Liver Damage in a Mouse Warm Ischemia and Reperfusion Model.

Transplantation 2017 02;101(2):322-331

1 Division of Liver and Pancreas Transplantation, Department of Surgery, Dumont-UCLA Transplant Center, David Geffen School of Medicine at University of California, Los Angeles, CA. 2 Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA. 3 Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, Los Angeles, CA. 4 Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles, CA.

Background: Bruton tyrosine kinase (Btk) is a central player in multiple signaling pathways of lymphoid and myeloid cells. Myeloid cells are crucial early effectors in organ ischemia-reperfusion (IR) injury. BTKB66 is a selective, irreversible inhibitor of Btk. In this study, we hypothesized that Btk inhibition would reduce hepatocellular injury in a murine model of liver warm hepatic IR.

Methods: First, BTKB66 was tested in in vitro models of lipopolysaccharide-mediated neutrophil and macrophage activation. Then, to assess its efficacy in vivo, BTKB66 was administered orally to mice for 7 days before subjecting them to 90 minutes of warm hepatic ischemia followed by reperfusion for 6 or 24 hours. Clinical and pathologic features in the livers, including AST, ALT, and a panel of cytokines and chemokines, were examined.

Results: BTKB66 potently inhibited lipopolysaccharide-mediated activation of bone marrow-derived neutrophils and macrophages in vitro. It also reduced the severity of IR injury as determined by AST and ALT levels, as well as immune cell infiltrates. BTKB66 significantly decreased hepatic markers of sterile inflammation, such as C-X-C motif chemokine 1, C-X-C motif chemokine 2, and C-X-C motif chemokine 10, in parallel with depression of serum markers of the myeloid cell activation, such as CCL5, CCL11, and C-X-C motif chemokine 5.

Conclusions: BTKB66 treatment ameliorated hepatocellular injury in a well-established model of liver partial warm ischemia and in situ reperfusion. These findings confirm that neutrophil recruitment and activation play an essential role in IR stress, and that targeting Btk activity may provide a useful approach for preventing hepatocellular damage and improving outcomes in liver transplantation.
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http://dx.doi.org/10.1097/TP.0000000000001552DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5263143PMC
February 2017

Multi-institutional phase II study on the feasibility of liver resection following preoperative mFOLFOX6 therapy for resectable liver metastases from colorectal cancers.

Int J Clin Oncol 2017 Apr 17;22(2):316-323. Epub 2016 Oct 17.

Department of Surgery, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Sho-go-in, Sakyo-ku, Kyoto, 606-8507, Japan.

Background: Although liver resection combined with preoperative chemotherapy is expected to improve outcomes of patients with resectable colorectal liver metastasis (CRLM), there is as yet insufficient clinical evidence supporting the efficacy of preoperative systemic chemotherapy. The aim of this phase II study was to assess the feasibility and efficacy of preoperative FOLFOX systemic chemotherapy for patients with initially resectable CRLM.

Methods: A prospective multi-institutional phase II study was conducted to evaluate the feasibility and efficacy of preoperative chemotherapy for resectable CRLM (ClinicalTrials.gov identifier number NCT00594529). Patients were scheduled to receive 6 cycles of mFOLFOX6 therapy before liver surgery. The primary endpoint was the macroscopic curative resection rate.

Results: A total of 30 patients were included in this study. Two patients who were diagnosed with hepatocellular and intrahepatic cholangiocellular carcinoma based on pathology were excluded from the analysis. More than half of the patients (57 %) had solitary liver metastasis. The completion rate of preoperative chemotherapy was 64.3 % and the response rate was 53.6 %. Two patients were unable to proceed to liver resections due to disease progression and severe postoperative complications following primary tumor resection. Macroscopic curative resection was obtained in 89.3 % of eligible patients. Postoperative mortality and severe complication (≥Gr. 3) rates were 0 and 11 %, respectively. The 3-year overall and progression-free survival rates were 81.9 and 47.4 %, respectively.

Conclusion: Our phase II study demonstrated the feasibility of liver resection combined with preoperative mFOLFOX6 therapy in patients with initially resectable CRLM. Further study is warranted to address the oncological effects of preoperative chemotherapy.
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http://dx.doi.org/10.1007/s10147-016-1050-5DOI Listing
April 2017
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