Fat-Derived Hormone Adiponectin Combined with FTY720 Significantly Improves Small-for-Size Fatty Liver Graft Survival

Owing to the discrepancy between organ donation and the demand for liver transplantation, expanding the liver donor pool is of vital importance. However, marginal liver grafts, such as small-for-size and/or fatty grafts, were associated with primary graft nonfunction or poor function. Therefore, novel combination therapies to rescue small-for-size fatty liver grafts should be investigated. In this study, we applied a combination therapy using a fat-derived hormone adiponectin (anti-steatosis) plus immunomodulator FTY720 (anti-inflammatory) in a rat liver transplantation model using small-for-size fatty liver grafts, and investigated the underlying protective mechanism such as anti-steatosis, intra-graft energy metabolism, hepatic microcirculatory changes, cell signaling cascades for survival, apoptosis and inflammation. The current study demonstrated that even a single treatment of adiponectin or FTY720 improved the 7-day graft survival from 0% to 62.5% (p = 0.001). The combination therapy significantly increased the 7-day graft survival rate to 100% by remarkable attenuation of graft steatosis and acute phase inflammatory response, significant activation of cell survival Akt pathway and maintenance of intra-graft adenosine triphosphate metabolism and improvement of hepatic microcirculation. In conclusion, the fat-derived hormone adiponectin combined with FTY720 might be a novel combination drug therapy for prevention of small-for-size fatty liver graft injury.     

FK 409 ameliorates small-for-size liver graft injury by attenuation of portal hypertension and down-regulation of Egr-1 pathway

OBJECTIVE: To investigate whether low-dose nitric oxide donor FK 409 could attenuate small-for-size graft injury in liver transplantation using small-for-size grafts. SUMMARY BACKGROUND DATA: The major concern of live donor liver transplantation is small-for-size graft injury at the early phase after transplantation. Novel therapeutic strategies should be investigated. METHODS: We employed a rat orthotopic liver transplantation model using small-for-size (40%) graft. FK 409 was given at 30 minutes before graft harvesting (2 mg/kg) to the donor and immediately after reperfusion (1 mg/kg) to the recipient (FK group). Graft survival, intragraft genes expression, portal hemodynamics, and hepatic ultrastructural changes were compared between the 2 groups. RESULTS: Seven-day graft survival rates in the FK group were significantly improved compared with those of rats not receiving FK 409 (control group; 80% versus 28.6%, P = 0.018). In the FK group, portal pressure was significantly decreased within the first 60 minutes after reperfusion whereas in the control group, transient portal hypertension was observed. Intragraft expression (both mRNA and protein) of early growth response-1, endothelin-1, endothelin-1 receptor A, tumor necrosis factor-alpha, macrophage-inflammatory protein-2, and inducible nitric oxide synthase was significantly down-regulated accompanied with up-regulation of heme oxygenase-1, A20, interferon-gamma-inducible protein-10, and interleukin-10 during the first 24 hours after reperfusion. Hepatic ultrastructure, especially the integrity of sinusoids was well protected in the FK group. CONCLUSIONS: Low-dose FK 409 rescues small-for-size grafts in liver transplantation by attenuation of portal hypertension and amelioration of acute phase inflammatory response by down-regulation of Egr-1, together with prior induction of heat shock proteins.     

Rapamycin Attenuates Liver Graft Injury in Cirrhotic Recipient—The Significance of Down-Regulation of Rho-ROCK-VEGF Pathway

To investigate whether rapamycin could attenuate hepatic I/R injury in a cirrhotic rat liver transplantation model, we applied a rat orthotopic liver transplantation model using 100% or 50% of liver grafts and cirrhotic recipients. Rapamycin was given (0.2 mg/kg, i.v.) at 30 min before graft harvesting in the donor and 24 h before operation, 30 min before total hepatectomy and immediately after reperfusion in the recipient. Rapamycin significantly improved small-for-size graft survival from 8.3% (1/12) to 66.7% (8/12) (p = 0.027). It also increased 7-day survival rates of whole grafts (58.3%[7/12] vs. 83.3%[10/12], p = 0.371). Activation of hepatic stellate cells was mainly found in small-for-size grafts during the first 7 days after liver transplantation. Rapamycin suppressed expression of smooth muscle actin, which is a marker of hepatic stellate cell activation, especially in small-for-size grafts. Intragraft protein expression and mRNA levels of vascular endothelial growth factor (VEGF) were down-regulated by rapamycin at 48 h both in whole and small-for-size grafts. Consistently, mRNA levels and protein expression of Rho and ROCK I were decreased by rapamycin during the 48 h after liver transplantation. In conclusion, rapamycin attenuated graft injury in a cirrhotic rat liver transplantation model by suppression of hepatic stellate cell activation, related to down-regulation of Rho-ROCK-VEGF pathway.     

Impaired hepatic regeneration by ischemic preconditioning in a rat model of small-for-size liver transplantation

OBJECTIVE: Graft size is one of the major risk factors in adult-to-adult living donor liver transplantation and rapid regeneration is an essential post-operative requirement. Ischemic preconditioning (IPC) has been shown to be an effective strategy in the reduction of hepatic ischemia-reperfusion injury and stimulation of liver regeneration. This study was designed to evaluate the effects of IPC on liver regeneration in small-for-size liver grafts. METHODS: We employed a rat orthotopic liver transplantation model using small-for-size (30%) grafts, in the presence or absence (control) of IPC (10 min of ischemia followed by 15 min of reperfusion). Survival rate, graft injury, hepatocellular proliferation, cell cycle progression, Stat3 activation, as well as TNF-alpha and IL-6 expression were assessed. RESULTS: IPC significantly enhanced the extent of graft injury and hindered hepatic regeneration in small-for-size liver grafts. The 7-day survival rate was also reduced by IPC, but failed to reach statistical significance. IPC did not affect TNF-alpha levels, but significantly decreased the elevation of IL-6 after reperfusion. These findings were correlated with down-regulation of cyclin E and cyclin D1, and decreased numbers of PCNA-positive nuclei in IPC grafts. These results were inconsistent with Stat3 activation, as P-Stat3 exhibited a stronger and prolonged pattern of expression in the IPC group, compared to controls. CONCLUSIONS: Ischemic preconditioning may impair liver regeneration in small-for-size liver grafts by decreasing IL-6 and blunting cell cycle progression, through a mechanism at least partially independent of Stat3.     

Attenuation of acute phase shear stress by somatostatin improves small-for-size liver graft survival.

The major concern of living donor liver transplantation is small-for-size graft injury at the early phase after transplantation. Novel therapeutic strategies should be developed. To investigate the protective effect of somatostatin related to hemodynamic stress on small-for-size liver graft injury, we applied a treatment regimen of low-dose somatostatin in a rat orthotopic liver transplantation model using small-for-size grafts (median, 38.7%; range, 35-42%). Somatostatin was given at 5 minutes before total hepatectomy and immediately after reperfusion in the recipient (20 microg/kg). Graft survival, portal hemodynamics, intragraft gene expression and hepatic ultrastructural changes were compared between the rats with or without somatostatin treatment. Seven-day graft survival rates in the somatostatin treatment group were significantly improved compared to the control group (66.7% vs. 16.7%, P = 0.036). In the treatment group, portal pressure and hepatic surface blood flow were significantly decreased within the first 30 minutes after reperfusion, whereas in the control group, transient portal hypertension and excessive hepatic blood flow were observed. Intragraft expression (both messenger RNA and protein) of endothelin-1 was significantly downregulated accompanied with upregulation of heme oxygenase-1 and A20. Better preservation of liver function was found in the treatment group. Hepatic ultrastructure, especially the integrity of sinusoids, was well protected in the treatment group. In conclusion, low-dose somatostatin rescues small-for-size grafts from acute phase injury in liver transplantation by attenuation of acute-phase shear stress that resulted from transient portal hypertension.     

采用不含肝中静脉的右半肝行成人间活体肝移植

目的探讨采用不含肝中静脉的右半肝行成人间活体肝移植的可行性及安全性。方法2002年1月至2005年8月,我院施行了16例成人间右半肝活体肝移植,术中采用了不含肝中静脉的右半肝移植物,同时进行了一系列改良的手术技术包括肝右静脉的重建,右肝下静脉的重建,肝中静脉分支的搭桥等改进。结果全组供者无严重并发症及死亡。前2例受者中,1例发生肝静脉吻合口狭窄,1例因发生小肝综合征,死于肝功进行性恶化。后14例受者中发生并发症5例:急性排斥反应,肝动脉栓塞,胆漏,左膈下脓肿及肺部感染各1例;1例再移植术后肺部感染死于MODS。14例中除肝右静脉与下腔静脉(IVC)直接吻合外,其中5例加行右肝下静脉重建,另5例采用自体大隐静脉搭桥行肝中静脉分支与IVC重建,保证了右肝的流出道通畅。移植物与受者重量比(GRWR)为0.72%~1.15%,11例<1.0%,其中2例<0.8%,无小肝综合征发生。结论采用了改进的手术技术,特别是肝静脉流出道的充分重建可有效的避免小肝综合征,从而使采用不含肝中静脉的活体右半肝移植成为安全可靠的手术方式。     

Amphiregulin Stimulates Liver Regeneration After Small‐for‐Size Mouse Liver Transplantation

This study investigated whether amphiregulin (AR), a ligand of the epidermal growth factor receptor (EGFR), improves liver regeneration after small‐for‐size liver transplantation. Livers of male C57BL/6 mice were reduced to ～50% and ～30% of original sizes and transplanted. After transplantation, AR and AR mRNA increased in 50% but not in 30% grafts. 5‐Bromodeoxyuridine (BrdU) labeling, proliferating cell nuclear antigen (PCNA) expression and mitotic index increased substantially in 50% but not 30% grafts. Hyperbilirubinemia and hypoalbuminemia occurred and survival decreased after transplantation of 30% but not 50% grafts. AR neutralizing antibody blunted regeneration in 50% grafts whereas AR injection (5 μg/mouse, iv) stimulated liver regeneration, improved liver function and increased survival after transplantation of 30% grafts. Phosphorylation of EGFR and its downstream signaling molecules Akt, mTOR, p70S6K, ERK and JNK increased markedly in 50% but not 30% grafts. AR stimulated EGFR phosphorylation and its downstream signaling pathways. EGFR inhibitor PD153035 suppressed regeneration of 50% grafts and largely abrogated stimulation of regeneration of 30% grafts by AR. AR also increased cyclin D1 and cyclin E expression in 30% grafts. Together, liver regeneration is suppressed in small‐for‐size grafts, as least in part, due to decreased AR formation. AR supplementation could be a promising therapy to stimulate regeneration of partial liver grafts.     

Exogenous biliverdin ameliorates ischemia-reperfusion injury in small-for-size rat liver grafts

OBJECTIVE: This study sought to investigate the protective potential of exogenous biliverdin (BV) for small-for-size rat liver transplants. METHODS AND RESULTS: We employed a rat orthotopic liver transplantation model using small-for-size grafts. BV (50 mumol/kg, intravenously) given to the recipient immediately before reperfusion increased 7-day survival rates (90% vs 40% in controls) and significantly diminished hepatocyte injury, as compared with a control group. These effects correlated with improved liver function and preserved hepatic architecture. BV adjuvant increased antioxidant ability, suppressed proinflammatory tumor necrosis factor-alpha expression, down-regulated proapoptotic molecules (cytochrome C and caspase-3), and inhibited most apoptotic cells. After reperfusion, there was a significant increase of c-Jun NH(2)-terminal kinase (JNK) activation and AP-1 binding ability. BV treatment effectively repressed JNK/AP-1 activation, indicating that a beneficial effect of BV treatment may be related to suppression of the JNK/AP-1 pathway. CONCLUSIONS: BV treatment alleviated ischemia-reperfusion injury at least in part via inhibition of the proinflammatory and proapoptotic JNK/AP-1 pathway. Our findings provide a rationale for a novel therapeutic approach using BV to maximize the availability of small-for-size liver grafts.     

成人间活体肝移植的手术技术改进(附13例报告)

目的探讨成人间活体肝移植的手术技术改进.方法2005年3-6月,施行了13例成人间右半肝活体肝移植,其中1例接受了2个左半肝,另1例接受了1个活体右半肝,1个尸体左半肝,术中采用了改良的手术技术,包括右肝静脉的重建,肝中静脉分支的搭桥,肝动脉搭桥及胆道吻合的改进.结果全组供体无严重并发症及死亡,受体发生并发症4例,包括肝动脉栓塞,胆漏,右膈下脓肿及肺部感染各1例,1例再移植因术后肺部感染,导致多器官衰竭（MOF）死亡.13例中除右肝静脉与下腔静脉（IVC）直接吻合,5例加行右肝下静脉重建,另5例采用自体大隐静脉搭桥行肝中静脉分支与IVC重建,保证了右肝的流出道通畅.移植物与受体重量比（GRWR）为0.72%至1.24%,其中9例＜1.0%,2例＜0.8%,无小肝综合征发生.结论采用了改进的手术技术,特别是肝静脉流出道的充分重建可有效避免小肝综合征,从而使活体右半肝移植成为相当安全的手术.     

改进成人间活体供肝移植的手术技术

目的研究并改进成人间活体供肝移植的手术技术。方法自2002年1月至2005年8月,施行了16例成人间活体右半供肝移植。手术中改进了技术,包括右肝静脉重建、肝中静脉分支搭桥、肝动脉搭桥及胆道吻合等。结果所有供者均无严重并发症及死亡。移植肝与受者重量比（GRWR）为0．72％～1．24％,其中9例〈1．0％,2例〈0．8％。手术除了采用移植肝的右肝静脉与受者下腔静脉（IVC）直接吻合外,5例加行右肝下静脉重建、5例取自体大隐静脉行肝中静脉分支与IVC间搭桥,保证了右肝流出道通畅。最早手术的2例受者中,1例发生肝静脉吻合口狭窄,另1例发生小肝综合征,最终导致死亡。后阶段手术的14例受者均未发生小肝综合征;发生并发症5例,分别为急性排斥反应、肝动脉栓塞、胆漏、左膈下脓肿及肺部感染;1例再次肝移植后因肺部感染,多器官功能衰竭（MOF）死亡。结论活体供肝移植中采用改进的手术技术,特别是肝静脉流出道重建的方法,可有效避免发生小肝综合征。     

Auxiliary Partial Orthotopic Living Donor Liver Transplantation: Kyoto University Experience

Auxiliary partial orthotopic liver transplantation (APOLT) was initially indicated as a potentially reversible fulminant hepatic failure and non-cirrhotic metabolic liver disease to compensate for enzyme deficiency without complete removal of the native liver. We expand our indication of APOLT for small-for-size grafts to support the function of implanted grafts during the early post-operative period, and for ABO-incompatibility to sustain a patient's life if the patient has a graft failure. We retrospectively reviewed 31 patients undergoing APOLT from living donor. The indication of APOLT was fulminant hepatic failure in 6, non-cirrhotic metabolic liver disease in 6, small-for-size grafts in 13 and ABO-incompatible cases in 6. The cumulative survival rate for APOLT at 1 and 5 years was 57.9% and 50.6%, and 78.8% and 73.8% for standard LDLT. None of the patients who underwent transplantation with APOLT for fulminant hepatic failure had long-term patient survival. The incidence of acute cellular rejection was higher in APOLT (58.1%) than standard LDLT (35.0%). Biliary complication was higher and the need for retransplantation was greater in APOLT than standard LDLT (p < 0.01). The results suggest that the indications of APOLT should be reconsidered in view of the risk for complications and retransplantation.     

Protective effect of adenosine A2A receptor activation in small-for-size liver transplantation

The aim of the present study was to investigate the potential role of adenosine A(2A) receptor (A(2A)R) activation in small-for-size liver transplantation. A rat orthotopic liver transplantation model was performed by using 40% (range: 36-46%) liver grafts. Recipients were given either saline (control group) or CGS 21680 (2-p-(2-Carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine hydrochloride, a selective A(2A)R agonist), or CGS 21680+ ZM 241385 (a selective A(2A)R antagonist) immediately after reperfusion for 3 h. Compared with control group, CGS 21680 used at both low dose (0.05 microg/kg/min) and high dose (0.5 microg/kg/min) increased the survival rate from 16.7% (2/12) to 83.3% (10/12) and 66.7% (8/12), respectively. These effects correlated with improved liver function and preserved hepatic architecture. CGS 21680 effectively decreased neutrophil infiltration, suppressed pro-inflammatory (TNF-alpha, IL-1beta and IL-6) expression, promoted expression of antiapoptotic molecules, and inhibited apoptosis. The effects of CGS 21680 were prevented when ZM 241385 was co-administrated. In conclusion, the present study showed that A(2A)R activation alleviated portal hypertension, suppressed inflammatory response, reduced apoptosis, and potentiated the survival of small-for-size liver grafts. Our findings provide the rationale for a novel therapeutic approach using A(2A)R activation to maximize the availability of small-for-size liver grafts.     

Antiinflammatory properties of IL-10 rescue small-for-size liver grafts.

The present study aims to investigate the potential therapeutic role of interleukin-10 (IL-10) in small-for-size liver transplantation. A syngenic rat orthotopic liver transplantation model was performed using either whole or 40% liver volume of Lewis rats as grafts according to the experimental design. IL-10 was given to the 40% grafts right after reperfusion, and also at 24 and 48 hours after transplantation. When no treatment was given, less than 40% of the small-for-size grafts survived indefinitely, whereas IL-10 treatment could increase the long-term survival rate of the small-for-size grafts to 80%. The 40% grafts presented with extensive areas of necrosis and increased number of apoptotic cells at the early phases after reperfusion. In addition, upregulation of plasma protein carbonyl content (PCC) levels was also detected in the 40% graft group. IL-10 treatment suppressed the upregulation of allograft inflammatory factor-1 (AIF-1) on macrophages in the 40% grafts, and at the same time, decreased the levels of plasma PCC, and improved the histology and function of the 40% grafts. The expression of inducible nitric oxide synthase (iNOS), tumor necrosis factor (TNF)-alpha, and caspase 9 in the 40% grafts were upregulated after reperfusion, whereas the augmentation could be suppressed by the administration of IL-10. Finally, IL-10 culture could block AIF-1-mediated NO production and downregulate the expression of iNOS and TNF-alpha in a macrophage cell line. In conclusion, IL-10 rescued the small-for-size liver grafts by its antiinflammatory properties, through inhibition of AIF-1 mediated proinflammatory and proapoptotic activities of the macrophages during the early period after ischemia/reperfusion.     

缺血预处理对大鼠减体积肝移植术后Akt生存信号通路的影响及其意义

目的 探讨缺血预处理(IPC)对大鼠减体积肝移植术后Akt生存信号通路的影响及意义.方法 将36只成年雄性SD大鼠随机分为2组:50%减体积肝移植组(Control组)和IPC组,Western blot检测肝组织总Akt和p-Akt及其下游的p-Bad和p-GSK3β蛋白水平,同时结合血清学和组织病理学分析Akt生存信号通路变化的意义.结果 与Control组比较,IPC组术后6、24 h丙氨酸转氨酶(ALT)水平显著下降(6 h:1064.49±126.53比802.90±82.39;24 h:1401.13±172.73比943.80±116.25,P<0.01);Control组术后24 h,肝细胞明显空泡样变性伴局部坏死,小叶结构破坏,门脉周围水肿、充血,炎症细胞浸润明显,而IPC组损伤减轻;Western blot结果显示:与Control组比较,IPC组术后2、6、24 h肝组织中p-Akt、p-Bad、p-GSK3β蛋白水平上调.结论 IPC明显减轻减体积肝移植术后再灌注损伤,其机制可能与激活Akt生存信号通道密切相关.     

Living Donor Liver Transplantation Using Dual Grafts from Two Donors: A Feasible Option to Overcome Small‐for‐Size Graft Problems?

Living donor liver transplantation (LDLT) between adults inevitably implies two potential risks associated with a small-for-size graft for the recipient and small remnant liver for the donor. To overcome these problems, LDLT using dual grafts from two independent donors can be a solution, in which sufficient graft volume can be obtained while preserving donor safety. We present a case of LDLT that was managed successfully by using right and left lobe dual grafts from two donors. The recipient was a large-size male with hepatitis C cirrhosis complicated by multiple hepatocellular carcinomas (HCCs). The first donor donated a right lobe graft and the second donor donated a left lobe plus caudate lobe graft with the middle hepatic vein. Graft function was excellent throughout the course without evidence of small-for-size syndrome. In conclusion, LDLT using dual grafts can be justified in a selected case to avoid small-for-size graft problems without increasing independent donor risks.     

大鼠小体积肝脏移植后早期肝内细胞因子的变化

目的 研究不同冷缺血条件下大鼠小体积肝移植(30%标准体积)后早期肿瘤坏死因子α(TNF-α)及白细胞介素6(IL-6)的变化,及其与肝脏再生的关系.方法 建立Lewis大鼠30%标准体积的原位肝移植模型.根据供肝在UW液中冷保存时间的不同,将受者分为3组:冷缺血1 h组、冷缺血8 h组和冷缺血16 h组,每组均为20只.观察受者存活情况至术后第7天,并分别在移植肝恢复血流后90 min、1 h、2 h、4 h和7 d收集样本,检测移植肝组织中TNF-α和IL-6表达情况,肝细胞DNA的合成情况,进行移植肝的形态学观察.结果 大鼠肝移植手术成功率均为100%.移植后第7天,冷缺血1 h和8 h组受鼠的存活率均为100%.冷缺血16 h组受鼠的存活率较低,移植后第7天无受鼠存活.冷缺血1 h组TNF-α和IL-6的表达水平较低,冷缺血8 h组和冷缺血16 h组TNF-α和IL-6的表达则高于冷缺血1 h组(F=58.81和F=184.12,P<0.05).冷缺血8 h组和冷缺血16 h组间TNF-α和IL-6的表达的差异无统计学意义.冷缺血1 h组增殖细胞数目明显高于冷缺血8 h组,差异有统计学意义(t=5.59,P<0.05).移植术后24h,冷缺血1 h组移植肝有轻度的组织学损伤;冷缺血8 h组移植肝有轻度的窦状隙扩张和轻度的炎症;冷缺血16 h组移植肝有局部淤血,存在肝细胞崩解和坏死等改变.结论 在小体积肝移植后早期,TNF-α和IL-6的上调表达对肝脏再生有重要意义.不同冷缺血时间的小体积肝脏移植物内存在早期启动肝脏再生的信号.     

成人间活体肝移植体会：附3例报告

目的总结和分析成人间活体肝移植(LDLT)的临床经验。方法对2007年2月—2007年7月的3例成人间活体肝移植的临床资料进行回顾性分析。结果供体为供体右半肝(不带肝中静脉)1例,供体扩大左半肝(带肝中静脉、尾状叶)2例,GV/SLV均≥40%。3对供者及患者术后均恢复良好,无小肝综合征发生,均未出现严重并发症。术后左半肝供者较右半肝供者肝功能恢复更快。结论如左半肝GV/SLV≥40%,可优先选择左半肝作为供肝;胆道重建不必放置胆管引流管;成人间LDLT是治疗终末期肝病的安全有效的手段。     

Delivery of Cu/Zn-superoxide dismutase genes with a viral vector minimizes liver injury and improves survival after liver transplantation in the rat

BACKGROUND: Oxygen-derived free radicals play a central role in pathomechanisms of reperfusion injury after organ transplantation. Endogenous radical scavenger systems such as superoxide dismutase (SOD) degrade toxic radicals; however, SOD is degraded rapidly when given exogenously. Therefore, the hypothesis that treatment of the donor liver with an adenoviral vector encoding the Cu/Zn-SOD gene (Ad-SOD1) would lead to permanent gene expression and therefore protect the organ against injury and increase survival in a rat model of liver transplantation was tested. METHODS: Some donors were infected with Ad-SOD1, whereas untreated grafts and livers infected with the indicator gene lacZ encoding bacterial beta-galactosidase (Ad-lacZ) served as controls. After orthotopic liver transplantation, survival, serum transaminases, and histopathology were evaluated. RESULTS: Approximately 80% of hepatocytes expressed beta-galactosidase 72 hr after injection of Ad-lacZ. Moreover, SOD1 gene expression and activity were increased 3- and 10-fold in the Ad-SOD1 group, respectively. After transplantation, 20-25% of rats treated with Ad-lacZ survived. In contrast, all SOD1-treated animals survived. Transaminases measured 8 hr after transplantation in Ad-SOD1 rats were only 40% of those in controls, which increased 40-fold above normal values. Approximately 20% of hepatocytes in untreated and Ad-lacZ-infected organs were necrotic 8 hr after reperfusion, whereas necrosis was nearly undetectable in grafts from rats treated with Ad-SOD1. CONCLUSIONS: This study provides clear evidence for the first time that gene therapy with Ad-SOD1 increases survival and decreases hepatic injury after liver transplantation. Genetic modification of the liver represents a future approach to protect organs against injury where oxygen-derived free radicals are involved.