Warm flush at 37 °C following cold storage attenuates reperfusion injury in preserved rat livers

Abstract Pretransplant rinse solutions have been shown to reduce reperfusion injury in cold-stored liver grafts, especially at the nonparenchymal level in sinusoidal endothelial cells (SEC). In this study, different rinse temperatures were tested in a rat liver preservation model. Livers were washed out in situ via the portal vein with cold (4°C) University of Wisconsin (UW) solution, and after hepatectomy (t0), were stored for 8,16, or 24 h of cold ischemia time (CIT). After storage, livers were flushed with UW solution at either 4 °C, 20 °C, or 37 °C and reperfused for 90 min (37 °C). Control livers were reperfused at t0 without preflush. Levels of hyaluronic acid (HA), purine nucleoside phosphorylase (PNP), AST, and LDH were measured in the reperfusion medium. Bile production was monitored during reperfusion. At the end of reperfusion, liver biopsies were taken for enzyme histochemistry (5′-nucleotidase and LDH). After 8-h CIT and a flush at 4°C, a release of endogenous HA (-7 %) was observed, whereas uptake of exogenous HA occurred after the 20°C flush (2 %, P = NS) and after the 37°C flush (24 %, p < 0.001). HA release occurred at all three preflush temperatures after the 16-h CIT but was significantly lower when flushed at 37 °C (-10 %) that at 4 °C and 20 °C (-64 % and -17 %, respectively, p =0.05). After the 24-h CIT, the release of endogenous HA increased in the 4 °C and 20 °C preflush groups, but not in the 37 °C group. Levels of PNP and AST increased until the 24-h CIT in all groups but were significantly lower after preflush at 37 °C. Release of LDH did not increase with increasing periods of cold storage in any of the flush series. Compared to control livers, mean bile production during reperfusion was significantly decreased following preflush at 4°C or 37 °C after all periods of CIT. No differences in mean bile production could be demonstrated in the three preflush groups after any period of CIT. LDH activity in liver tissue was best preserved after the 8 and 16-h CIT in combination with the 37 °C preflush, indicating less hepatocellular damage. In conclusion, in cold stored rat livers flushed at 37 °C before reperfusion, SEC and hepatocellular damage is attenuated.     

体外持续肝脏灌注常温保存和HTK液低温保存无心跳供肝效果的比较

目的 比较应用组氨酸-色氨酸-酮戊二酸(HTK)液低温保存和体外持续肝脏灌注(ECLP)系统常温保存无心跳供肝的效果.方法 按保存方法不同将供肝随机分为A组和B组:供肝切取后,A组用HTK液在低温下保存10 h;B组用ECLP系统在常温下用稀释的自体血液持续灌注10 h.两组供肝再经过60 min冷缺血期后,连接ECLP系统用稀释的自体血液再灌注4 h.观察再灌注后1、2、3、4 h四个时间点的胆汁分泌量,门静脉和肝动脉的压力,肝脏耗氧率的变化,灌注液中丙氨酸转氨酶(ALT)、乳酸脱氢酶(LDH)、葡萄糖水平以及灌注后供肝的常规病理和超微病理变化.结果 B组再灌注后1、2、3、4 h时间点的胆汁分泌量,门静脉和肝动脉的压力,灌注液中ALT、LDH和葡萄糖水平,以及2、3、4 h时间点的耗氧率与A组比较,差异均有统计学意义(P＜0.05或P＜0.01);B组供肝的病理损害程度较A组轻.结论 供肝切取后10 h内,利用ECLP系统持续灌注常温保存比用HTK液单纯低温保存在维持无心跳供肝的功能和生理活性方面效果更好.     

Hyaluronic acid uptake in the assessment of sinusoidal endothelial cell damage after cold storage and normothermic reperfusion of rat livers

The uptake of hyaluronic acid (HA) was used to assess preservation damage to sinusoidal endothelial cells (SEC) during cold storage and subsequent normothermic reperfusion of rat livers. After 8, 16, 24, and 48 h storage in University of Wisconsin (UW) solution, livers were gravity-flushed via the portal vein with a standard volume of cold UW solution containing 50 g/l HA. The effluent was collected for analysis of HA, aspartate aminotransferase (AST), and lactate dehydrogenase (LDH). The mean uptake of HA at 0 h was 59.1%±4.6% (mean±SEM). After 8 h of storage, HA uptake was similar (55.5%±7.3%), whereas after 16 h of storage it was reduced to 34.7%±5.8%. At 24 and 48 h of storage, no uptake of HA was found. In a second series of experiments, livers were stored in UW solution and subsequently reperfused for 90 min with a Krebs-Henseleit solution (37°C) in a recirculating system containing 150 g/l HA. Following 8 h of storage, 34.6%±8.0% of the initial HA concentration was taken up from the perfusate. After 16 and 24 h of storage, no uptake of HA was found. The results of this study indicate that damage to SEC occurs progressively during storage, leading to zero uptake of HA by the rat livers at 24 h of cold ischemia time. Additional reperfusion injury to the SEC was demonstrated by the reduced ability of the SEC to take up HA following normothermic reperfusion. The uptake of exogenous HA in preserved livers, used as a tool to assess SEC injury, enables the detection of early preservation damage.     

The isolated perfused porcine liver: assessment of viability during and after six hours of perfusion

Isolated liver perfusion was developed for the study of liver physiology and preservation. The recent development of new perfusion devices and appropriate liver preservation solutions prompted us to reconsider liver perfusion for the specific purpose of evaluating viability in terms of biochemical changes, paying special attention to modifications in the histological ultrastructure. Twenty-two isolated pig livers were perfused with autologous blood. Arterio-portal perfusions were carried out using an extracorporeal perfusion circuit with a hollow fibre membrane oxygenator. Four groups of pig livers were studied using three different liver flushing solutions [Ringer's lactate, ELOHES, and University of Wisconsin (UW)] and two different oxygenation modalities. Liver function tests and histological studies were done. Our results revealed that a high partial oxygen pressure (PO₂) level was deleterious to the ultrastructural elements of hepatocytes, in particular to the mitochondria. It was also associated with deficient metabolic performance, i. e., poor bile production and lack of aerobic metabolism. Normal blood gas values could be obtained with the use of air for liver oxygenation. Flushing of the liver with Ringer's lactate or a macromolecular solution such as ELOHES was associated with severe liver cell injuries, as reflected by a marked rise in liver enzymes and histological lesions. Satisfactory results were obtained when UW solution was used for liver harvesting. We conclude that an appropriate liver preservation solution, normal blood gas values, and normal physiological arterio-portal pressure and blood flow are essential for appropriate liver function with preservation of liver architecture and of hepatocyte ultrastructures. Total bilirubin in bile and Factor V are sensitive indicators of good liver function. Received: 24 January 1997 Received after revision: 18 April 1997 Accepted: 24 April 1997     

冷保存对大鼠部分移植肝再生的影响

目的探讨冷保存对大鼠部分肝移植术后肝再生的影响。方法健康SD大鼠分为Ⅰ组（肝切除组）、Ⅱ组（冷保存1h部分肝移植组）和Ⅲ组（冷保存8h部分肝移植组）。观察各实验组生存率，比较各组术后1、6、12、24、48、72、168h肝质量／体质量比率、肝再生率、有丝分裂指数及增殖细胞核抗原表达。结果Ⅰ、Ⅱ、Ⅲ组7d存活率分别为100％、90％、40％；Ⅲ组术后2～3d大鼠肝质量／体质量比率、肝再生率、有丝分裂指数较Ⅰ、Ⅱ组明显偏低（P〈0．05）；Ⅲ组术后12h内增殖细胞核抗原表达较其余两组明显偏低（P〈0．05），48h才达高峰，至第7天阳性表达仍处高水平。结论长时间冷保存降低了部分肝移植术后的肝再生能力和大鼠术后生存率。     

三七总皂甙对大鼠肝脏低温保存再灌注期间肝细胞凋亡的影响

目的　研究三七总皂甙 (PNGS)对大鼠肝脏低温保存再灌注期间肝细胞凋亡的影响及其机制。方法　采用大鼠离体肝脏再灌注模型 (IPRL) ,用Fura 2法测定低温保存 2h后肝细胞内钙离子浓度 ;经乳酸林格氏液 (LR)低温保存 2 4h的肝脏再灌注 30min后进行肝脏功能检测、氧自由基代谢产物、肝细胞凋亡、Bcl 2蛋白表达及形态学观察。LR和DMEM液中加入不同浓度PNGS。结果　大鼠肝细胞内钙离子浓度、MDA、SOD、肝细胞凋亡及Bcl 2蛋白表达阳性率等项指标各实验组明显好于对照组 (P <0 0 1) ,PNGS对大鼠肝细胞凋亡的保护作用显示出剂量依赖性 ,在 2 0 0～ 6 0 0mg范围内随剂量增加保护作用随之增强 (P <0 0 1) ,在 80 0～ 10 0 0mg范围内虽有增强 ,但无明显差别 (P >0 0 5 )。结论　PNGS减轻了大鼠肝脏在低温保存再灌注期间肝细胞凋亡 ,可能与通过抑制钙超载、抗氧自由基损伤、提高Bcl 2蛋白表达作用有关。     

持续低流量灌注对离体鼠心的保护作用

目的 比较低温静置保存和持续低流量灌注对离体鼠心的保护作用.方法 将24只SD雄性大鼠随机分成4组(n=6),根据保存技术和保存液的不同分为H1、H2、F1、F2组.4℃条件下,F1、H1组心脏分别浸于FWM液(阜外改良液)和HTK液中保存8 h;F2、H2组心脏以10cm H2O的压力分别持续灌注FWM液和HTK液8 h.比较复灌后各组心功能恢复率、心肌含水量、心肌酶漏出量及光镜心肌结构.结果 复灌后,F1组心脏均未复跳,心肌含水量和肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH)漏出量分别为(84.1±1.2)%、(16.2±7.4)IU/L、(86.1±10.6)IU/L,明显高于其余3组(P＜0.01).H2组心率、左室发展压、心率室内压乘积、冠脉流量恢复率为(80.2±5.3)%、(77.7±3.4)%、(63.8±3.1)%、(54.6±6.0)%,心肌含水量及心肌酶漏出量要低于其余各组(P＜0.05).结论 持续低流量灌注技术对心肌的保护作用优于低温静置保存技术;HTK液对心肌的保护作用优于FWM液.     

Assessment of hepatic viability during cold ischemic preservation

A reliable and easy method for assessing the viability of a cold ischemia-preserved donor liver prior to transplanation into the recepient is needed. Based on an earlier study, we hypothesized that liver free fatty acid (FFA) leakage into the preservation fluid may be a useful, atraumatic indicator of irreversible ischemic injury. The aim of the present study was to determine the time course and magnitude of liver FFA release into the preservation solution and its correlation with the duration of cold ischemic preservation compatible with survival after transplantation. Rat livers (n=48) were flushed and preserved with University of Wisconsin (UW) solution at 4°C for 0, 12, 24, and 48 h. Thereafter, half of the livers were analyzed for preservation fluid FFA (gas-liquid chromatography) and protein. The other half were perfused with Krebs-Henseleit (KH) solution at 37°C for 1 h. Bile secretion and liver enzyme release (SGOT, SGPT, and LDH) were measured in addition to perfusate FFA and protein. Total FFA in the preservation fluid was 24 g/g wet tissue after 12 h; it increased sharply 2.6-fold after 24 h and 3.7-fold after 48 h of preservation. Bile production was normal after 12 h of preservation but fell by 20% and 54% after 24 h and 48 h, respectively. LDH release rose from a value of 20 U/l at 0 time to 120 U/l and 260 U/l after 24 h and 48 h of preservation. These results suggest that liver viability declines sharply between 12 and 24 h of cold ischemic preservation, which corresponds with a sharp decrease in the 1-week survival from 100% to 33% after 12 h and 24 h, respectively, of cold ischemic preservation. We conclude that measuring FFA and LDH in the preservation solution of donor livers may be a useful means of assessing the quality of the cold-preserved liver before insertion into the recipient. We also speculate that a threshold FFA level in the UW preservation fluid indicating irreversible damage may be in the order of 35 g total FFA/g liver. Studies on the clinical applicability of our findings are currently under way.     

自制KYL液对大鼠肝脏低温保存后细胞凋亡影响的研究

目的 研究自制的KYL液对大鼠肝脏低温保存后细胞凋亡的影响。方法 采用大鼠肝脏非循环离体灌注模型（noncirculated isolated perfusion of ratliver，IPRL），随机以KYL液和UW液对大鼠肝脏保存0、4、8、16、24、48h，测定灌注流出液氧自由基代谢产物（丙二醛MDA和超氧化物歧化酶SOD）的含量，检测肝细胞内钙离子浓度，检测肝细胞凋亡率和凋亡相关基因表达，观察肝脏组织形态学变化。同时设生理盐水保存阴性对照组，了解器官保存液对大鼠肝脏有无保护作用。结果 KYL液保存的大鼠肝脏肝细胞内钙离子浓度较UW液保存者低，灌注流出液MDA和SOD含量与UW液保存者相近，两者肝细胞凋亡率及凋亡基因表达情况相近，光、电镜观察两者形态学变化基本一致。两组所有指标均较生理盐水保存组好，说明两种液体对大鼠肝脏均有保护作用。结论 自制的KYL液对大鼠肝脏的保存效果在钙拮抗方面略优于UW液，在抑制细胞凋亡方面与UW液相当，而在防止细胞水肿方面较UW液稍差。     

Effect of various concentrations of antibiotics on osteogenic cell viability and activity

Infection is a common complication of open fractures. Systemic antibiotics often cause adverse events before eradication of infected bone occurs. The local delivery of antibiotics and the use of implants that deliver both growth factors and antimicrobials are ways to circumvent systemic toxicity while decreasing infection and to reach extremely high levels required to treat bacterial biofilms. When choosing an antibiotic for a local delivery system, one should consider the effect that the antibiotic has on cell viability and osteogenic activity. To address this concern, osteoblasts were treated with 21 different antibiotics over 8 concentrations from 0 to 5,000 µg/ml. Osteoblast deoxyribonucleic acid content and alkaline phosphatase activity (ALP) were measured to determine cell number and osteogenic activity, respectively. Antibiotics that caused the greatest decrement include rifampin, minocycline, doxycycline, nafcillin, penicillin, ciprofloxacin, colistin methanesulfonate, and gentamicin; their cell number and ALP were significantly less than control at drug concentrations ≤200 µg/ml. Conversely, amikacin, tobramycin, and vancomycin were the least cytotoxic and did not appreciably affect cell number and ALP until very high concentrations were used. This comprehensive evaluation of numerous antibiotics' effects on osteoblast viability and activity will enable clinicians and researchers to choose the optimal antibiotic for treatment of infection and maintenance of healthy host bone. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1070–1074, 2011     

Effects of portal vein clamping time on rat liver microcirculation following extended cold preservation and transplantation

Orthotopic rat liver transplantation (ORLT) following extended cold preservation in University of Wisconsin (UW) solution has been shown to induce alterations of the hepatic microcirculation, mainly characterized by areas of no-reflow. The present study was performed to determine whether these alterations were related to the portal vein clamping time (PVCT), shown to be the main determinant of survival after ORLT. The hepatic microcirculation was evaluated using the multiple-indicator dilution curve (MIDC) technique after ORLT following 24-hour cold ischemia in UW solution. Two groups of rats were studied: one with PVCTs of less than 14 min (survival conditions) and one with PVCTs of more than 18 min (nonsurvival conditions). Four hours after ORLT, only long PVCTs were associated with small, but significant, nonperfused areas, about 10 % of the liver not being perfused by water; however, in both survival and nonsurvival conditions, the sinusoidal sieving function was well-maintained in perfused areas. In addition, liver viability parameters and hepatocyte function were similarly and minimally altered. The hepatic microcirculation is minimally altered 4 h after ORLT following extended cold preservation in UW solution, whatever the survival condition. Although only found after long PVCTs, the low magnitude of areas of no-reflow should not be associated with lethal injury of the transplanted liver, a finding further supporting the concept that survival after ORLT following 24-hour cold preservation in UW solution is mainly influenced by extrahepatic factors. Received: 1 December 1998 Received after revision: 6 May 1999 Accepted: 19 July 1999     

自制HYD液对大鼠肝脏低温保存后生化功能影响的研究

目的 研制自制ＨＹＤ液对大鼠肝脏低温保存后生化功能的影响。方法 采用大鼠肝脏非循环离体灌注模型，比较ＨＹＤ液，ＵＷ液和乳酸林格液（ＬＲ液）对大鼠肝脏６，１２，２４，３０，３６ｈ保存后生化功能的影响。结果 保存１２ｈ的肝脏，其各项生化功能ＨＹＤ组明显优于ＬＲ组。三磷酸腺苷，磷酸腺苷含量及Ａｔｋｉｎｓｏｎ能荷（ＡＥＣ），ＨＹＤ组略高于ＵＷ组，且保存３６ｈ差异有显著性。     

不同胆道灌洗方法对大鼠肝内胆管冷保存再灌注损伤的影响

目的观察不同胆道灌洗方法对大鼠移植肝肝内胆管冷保存再灌注损伤的影响。方法应用大鼠原位肝移植模型，将88只SD大鼠随机分为假手术组、胆道非灌洗组、UW液胆道灌洗组、生理盐水（NS）胆道灌洗＋UW液肝内胆道灌注保存组、HTK液胆道灌洗＋UW液肝内胆道灌注保存组、HTK液胆道灌洗＋HTK液肝内胆道灌注保存组。移植肝置于4℃林格液中保存2h后行原位肝移植。移植肝再灌注后24h，检测血清总胆红素（TB）、直接胆红素（DB）、碱性磷酸酶（AKP）、γ-谷酰转肽酶（GGT）及胆汁中GGT、葡萄糖（Glu）含量。在光镜及电镜下观察肝内胆管上皮细胞的形态学变化。结果与非灌洗组比较，胆道灌洗组术后各项指标明显改善（P〈0．01）；HTK液及NS灌洗组较UW液灌洗组术后指标改善明显（P〈0．05）。病理检测发现非灌洗组胆道损伤明显，各灌洗组胆道损伤程度明显改善，HTK液灌洗＋UW或HTK液灌注组对胆管上皮细胞的损伤较轻。结论移植肝冷保存前进行胆道灌洗可以明显减轻胆管上皮细胞的损伤，4℃HTK液灌洗＋4℃UW或HTK液灌注保存效果比较理想。     

Liver graft preservation methods during cold ischemia phase and normothermic machine perfusion

The growing demand for donor organs requires measures to expand donor pool.Those include extended criteria donors, such as elderly people, steatotic livers,donation after cardiac death, etc. Static cold storage to reduce metabolic requirements developed by Collins in late 1960 s is the mainstay and the golden standard for donated organ protection. Hypothermic machine perfusion provides dynamic organ preservation at 4°C with protracted infusion of metabolic substrates to the graft during the ex vivo period. It has been used instead of static cold storage or after it as short perfusion in transplant center. Normothermic machine perfusion(NMP) delivers oxygen, and nutrition at physiological temperature mimicking regular environment in order to support cellular function. This would minimize effects of ischemia/reperfusion injury.Potentially, NMP may help to estimate graft functionality before implantation into a recipient. Clinical studies demonstrated at least its non-inferiority or better outcomes vs static cold storage. Regular grafts donated after brain death could be safely preserved with convenient static cold storage. Except for prolonged ischemia time where hypothermic machine perfusion started in transplant center could be estimated to provide possible positive reconditioning effect. Use of hypothermic machine perfusion in regular donation instead of static cold storage or in extended criteria donors requires further investigation. Multicenter randomized clinical trial supposed to be completed in December 2021. Extended criteria donors need additional measures for graft storage and assessment until its implantation. NMP is actively evaluating promising method for this purpose.Future studies are necessary for precise estimation and confirmation to issue clinical practice recommendations.     

Observations on the ex situ perfusion of livers for transplantation

Normothermic ex situ liver perfusion might allow viability assessment of livers before transplantation. Perfusion characteristics were studied in 47 liver perfusions, of which 22 resulted in transplants. Hepatocellular damage was reflected in the perfusate transaminase concentrations, which correlated with posttransplant peak transaminase levels. Lactate clearance occurred within 3 hours in 46 of 47 perfusions, and glucose rose initially during perfusion in 44. Three livers required higher levels of bicarbonate support to maintain physiological pH, including one developing primary nonfunction. Bile production did not correlate with viability or cholangiopathy, but bile pH, measured in 16 of the 22 transplanted livers, identified three livers that developed cholangiopathy (peak pH < 7.4) from those that did not (pH > 7.5). In the 11 research livers where it could be studied, bile pH > 7.5 discriminated between the 6 livers exhibiting >50% circumferential stromal necrosis of septal bile ducts and 4 without necrosis; one liver with 25‐50% necrosis had a maximum pH 7.46. Liver viability during normothermic perfusion can be assessed using a combination of transaminase release, glucose metabolism, lactate clearance, and maintenance of acid‐base balance. Evaluation of bile pH may offer a valuable insight into bile duct integrity and risk of posttransplant ischemic cholangiopathy.     

持续低流量灌注对兔心肺联合保存的作用

应用Ｋａｎｅｋｏ兔异位心肺移植模型，研究持续低流量灌注技术对兔心肺联合保存的效果。选用健康家兔３２只，随机均分为对照组及实验组，保存期间，实验组心肺经主，肺动脉持续低流量灌注４℃的相庆保存液。心肺移植后，连续观察９０分钟，每３０分钟记录供体左室收缩压，舒张末压和右房压以及气道峰压和动脉血氧分压，以判定移植心肺功能。     

小鼠肝动脉重建对长时间冷保存移植肝存活率的影响

研究小鼠肝动脉重建(hepatic arterial reconstruction,HAR)对长时间冷保存移植肝存活率的影响.方法 同系雄性C57BL/6小鼠68只,分为冷保存时间(cold preservation time,CPT) 1 h组、CPT 4 h组、CPT 8 h组、CPT 16 h组、CPT 16 h+HAR组(供、受体小鼠各一半).小鼠供肝经门静脉灌注4℃ UW液后保存.肝脏移植采用缝合法(肝上下腔静脉)和袖套法 (门静脉、肝下下腔静脉) 吻合,胆管采用内支架管重建法.小鼠HAR采用含供体肝动脉的腹主动脉与受体腹主动脉端侧吻合的方法.观察术后5组受体小鼠移植肝的存活时间,用组织学检查肝细胞损伤情况,用免疫组织化学法观察肝细胞再生功能.结果 CPT 1 h、4 h、8 h组受体术后12 d移植物的存活率分别为7/7、10/10、9/9.CPT 16 h组除1例小鼠存活外,其余均在移植术后36 h内死亡,存活率为10%(1/10),CPT 16 h+HAR组受体90%(9/10)存活,两组存活率相比,差异有统计学意义(P<0.01).CPT 1 h、4 h组的移植物组织损伤程度轻,CPT 8 h 组的移植物组织损伤程度较前两组严重,但肝细胞再生活跃.CRT 16 h组的移植肝组织表现为广泛肝细胞空泡变性、坏死,肝细胞再生不明显.CPT 16 h+HAR组仅有轻度的肝窦淤血,肝细胞空泡变性、坏死改变,肝细胞再生活跃.结论 HAR可提高长时间冷保存移植肝的存活率.