Histidine-Tryptophan-Ketoglutarate (HTK) Is Associated with Reduced Graft Survival of Deceased Donor Kidney Transplants

Single-center studies have reported equivalent outcomes of kidney allografts recovered with histidine-tryptophan-ketoglutarate (HTK) or University of Wisconsin (UW) solution. However, these studies were likely underpowered and often unadjusted, and multicenter studies have suggested HTK preservation might increase delayed graft function (DGF) and reduce graft survival of renal allografts. To further inform clinical practice, we analyzed the United Network for Organ Sharing (UNOS) database of deceased donor kidney transplants performed from July 2004 to February 2008 to determine if HTK (n = 5728) versus UW (n = 15 898) preservation impacted DGF or death-censored graft survival. On adjusted analyses, HTK preservation had no effect on DGF (odds ratio [OR] 0.99, p = 0.7) but was associated with an increased risk of death-censored graft loss (hazard ratio [HR] 1.20, p = 0.008). The detrimental effect of HTK was a relatively late one, with a strong association between HTK and subsequent graft loss in those surviving beyond 12 months (HR 1.43, p = 0.007). Interestingly, a much stronger effect was seen in African-American recipients (HR 1.55, p = 0.024) than in Caucasian recipients (HR 1.18, p = 0.5). Given recent studies that also demonstrate that HTK preservation reduces liver and pancreas allograft survival, we suggest that the use of HTK for abdominal organ recovery should be reconsidered.     

Comparison of histidine-tryptophan-ketoglutarate (HTK) solution versus University of Wisconsin (UW) solution for organ preservation in human liver transplantation

Over a 30-month period, 60 patients (30 in each group) suffering from end-stage liver disease or primary hepatic malignancy and scheduled for liver transplantation were enrolled in a prospective, randomized study to compare two methods of liver preservation: histidinetryptophan-ketoglutarate (HTK) solution versus University of Wisconsin (UW) solution. Entry criteria for both groups were: age (18–65 years), elective surgery (transplantable or urgent category of the recipients), first transplantations and harvesting procedure performed by the same team. The parameters under investigation were the clinical and laboratory data preand post-transplantation, as well as follow-up data such as complications and survival. There were no significant differences in the two groups as far as the evaluation criteria were concerned, even when cold ischemia time was more than 15h (n=7). A slight, yet not significant, increase in late complications of the biliary anastomoses could be seen in the UW group. Hepatocellular injury (SGOT, SGPT, GLDH, lactate) appeared to be more marked in the HTK group. These results suggest that both HTK and UW solutions are appropriate for clinical use in liver transplantation, even if cold ischemia time is more than 15h.     

Histidine-Tryptophan-Ketoglutarate (HTK) Is Associated with Reduced Graft Survival in Pancreas Transplantation

Prior single-center studies have reported that pancreas allograft survival is not affected by preservation in histidine-tryptophan-ketoglutarate (HTK) versus University of Wisconsin (UW) solution. To expand on these studies, we analyzed the United Network for Organ Sharing (UNOS) database of pancreas transplants from July 2004, through February 2008, to determine if preservation with HTK (N = 1081) versus UW (N = 3311) impacted graft survival. HTK preservation of pancreas allografts increased significantly in this time frame, from 15.4% in 2004 to 25.4% in 2008. After adjusting for other recipient, donor, graft and transplant center factors that impact graft survival, HTK preservation was independently associated with an increased risk of pancreas graft loss (hazard ratio [HR] 1.30, p = 0.014), especially in pancreas allografts with cold ischemia time (CIT) ≥12 h (HR 1.42, p = 0.017). This reduced survival with HTK preservation as compared to UW preservation was seen in both simultaneous pancreas-kidney (SPK) transplants and pancreas alone (PA) transplants. Furthermore, HTK preservation was also associated with a 1.54-fold higher odds of early (<30 days) pancreas graft loss as compared to UW (OR 1.54, p = 0.008). These results suggest that the increasing use of HTK for abdominal organ preservation should be re-examined.     

UW与HTK保存液在肝脏移植术中临床效果对比的系统评价和meta分析

目的比较肝脏移植术中两种常用的器官保存液(UW液与HTK液)的临床效果。方法全面检索PubMed、Embase、Cochrane Library、中国期刊全文数据库、中国生物医学文献数据库、万方、维普等中英文数据库,纳入对比UW(UW液组)与HTK(HTK液组)两种保存液对移植肝脏保存效果的研究,提取资料并评价后用RevMan 5.3软件进行分析。结果最终纳入16篇文献共35 024例受者,meta分析结果显示,与UW液组比较,HTK液组的术后胆管并发症发生率[RR=1.30,95%CI(1.07,1.58),P=0.008]和术后7 d内天门冬氨酸氨基转移酶峰值[MD=112.45,95%CI(93.34,131.56),P<0.01]均较低,而术后移植肝原发性无功能发生率[RR=1.07,95%CI(0.52,2.18),P=0.86]、术后不同时间点移植肝和受者存活率(P>0.05)、术后再移植率[RR=0.83,95%CI(0.48,1.45),P=0.51]、急性排斥反应发生率[RR=1.27,95%CI(0.96,1.68),P=0.33]、7 d内丙氨酸氨基转移酶峰值[MD=31.79,95%CI(–161.84,225.42),P=0.75]、总胆红素水平[MD=19.42,95%CI(–10.83,49.67),P=0.21]、凝血酶原时间[MD=1.75,95%CI(0.01,3.49),P=0.838]等指标比较差异均无统计学意义。结论 HTK保存液对移植肝的保存安全且有效,具有与UW保存液相似的效果,关于二者对肝移植术后受者和移植肝远期存活率的影响仍需要大样本、高质量的随机对照试验研究来系统评价。     

UW器官保存液在胰腺移植中的研究进展

近年来,糖尿病发病率在全球呈快速增长的趋势,我国患病率已达到3%.多数Ⅰ型和部分Ⅱ型糖尿病患者需要采用外源性胰岛素注射控制血糖,患者不但要承受胰岛素注射带来的痛苦,而且还不可避免地要发生远期的并发症.因此,重建内源性胰岛分泌系统是近年来人们关注的热点.大量实验表明,胰腺移植不但可以中止胰岛素依赖性糖尿病并发症的发展,还可以转归已有的并发症,明显改善患者的预后.与其他器官移植一样,移植器官的获取及保存是移植成功的前提,由于胰腺组织的特殊性,不同的器官保存液对于保存胰腺效果不一.本文将对University of Wisconsin(UW)保存液在胰腺移植中作用作一论述.     

Comparison of solutions for preservation of the rabbit liver as tested by isolated perfusion

The University of Wisconsin (UW) solution consists of a relatively complex mixture of agents. In this study we compared simpler preservation solutions, namely, histidine-tryptophan-ketoglutarate glutarate (HTK) and phosphatebuffered sucrose (PBS) with different compositions of UW solution in the isolated perfused rabbit liver model. Livers were stored cold for 24 and 48 h. After 24 h of preservation, the amount of bile produced in UW-preserved livers was significantly greater (P<0.05) than that in HTK-preserved livers. Also, there was less LDH released into the perfusate in UW-preserved livers. There was more edema and lower K+/Na+ rations in HTK-preserved livers than in UW-preserved livers (all data P<0.05). After 48 h of preservation, the differences between livers preserved in UW or HTK solution were less noticeable than at 24 h and bile production was similar. LDH and AST release were greater in HTK-preserved livers than in UW livers, but these differences were not statistically significant. Preservation in PBS for 48 h was worse than in either UW or HTK solution. Substitution of polyethylene glycol (PEG) for hydroxyethyl starch (HES) in 48-h UW-preserved livers was not effective. We conclude that solutions simpler in composition than UW solution may be effective in kidney transplantation but do not appear suitable for successuful liver preservation.     

Histidine‐Tryptophan‐Ketoglutarate for Pancreas Allograft Preservation: The Indiana University Experience

Histidine‐tryptophan‐ketoglutarate solution (HTK) has been scrutinized for use in pancreas transplantation. A recent case series and a United Network for Organ Sharing data base review have suggested an increased incidence of allograft pancreatitis and graft loss with HTK compared to the University of Wisconsin solution (UW). Conversely, a recent randomized, controlled study failed to show any significant difference between HTK and UW for pancreas allograft preservation. This study was a retrospective review of all pancreas transplants performed at Indiana University between 2003 and 2009 comparing preservation with HTK or UW. Data included recipient and donor demographics, 7‐day, 90‐day and 1‐year graft survival, peak 30‐day serum amylase and lipase, HbA1c and C‐peptide levels. Of the 308 pancreas transplants, 84% used HTK and 16% UW. There were more SPK compared to pancreas after kidney and pancreas transplant alone in the HTK group. Donor and recipient demographics were similar. There was no significant difference in 7‐day, 90‐day or 1‐year graft survival, 30‐day peak serum amylase and lipase, HbA1c or C‐peptide. No clinically significant difference between HTK and UW for pancreas allograft preservation was identified. Specifically, in the context of low‐to‐moderate flush volume and short cold ischemia time (≤10 h), no increased incidence of allograft pancreatitis or graft loss was observed.     

Comparison of University of Wisconsin and University of Pittsburgh solutions for heart transplantation

The effectiveness of University of Wisconsin (UW) and University of Pittsburgh (UP) solutions for the preservation of rat hearts was compared. Lewis rat hearts were preserved with UW (group A, n=45) or UP (group B, n=45) solution for 0 or 24 h and then transplanted heterotopically into the recipients' abdomen. Ten recipients in each group were observed to obtain 1-week graft survival rates. Tissue water content and tissue content of adenine nucleotides were measured 2 h after transplantation in six grafts from each group. Six hearts preserved for 0 h and seven hearts preserved for 24 h were taken from each group 24 h after grafting for histopathology. The 1-week graft survival rates of groups A24 and B24 were 60% and 10%, respectively. In the 24-h preserved grafts, adenosine triphosphate (ATP) and energy charge [(ATP+adenosine diphosphate/2)/(ATP+adenosine diphosphate+adenosine monophosphate)] of groups A and B were 0.972±0.165 and 0.200±0.123 mg/g wet tissue (P<0.05) and 74.4% and 61.1% (P<0.05), respectively. The tissue water content of group A24 was 71.7%, whereas that of group B24 was 74.1% (P<0.05). Histopathology revealed more severe muscle edema and necrosis and infiltration of polymorphonuclear cells in group B24 than in group A24. We conclude that UW solution is more appropriate for rat heart preservation than UP solution.     

Increased Primary Non-Function in Transplanted Deceased-Donor Kidneys Flushed with Histidine-Tryptophan-Ketoglutarate Solution

Histidine-Tryptophan-Ketoglutarate (HTK) solution is increasingly used to flush and preserve organ donor kidneys, with efficacy claimed equivalent to University of Wisconsin (UW) solution. We observed and reported increased graft pancreatitis in pancreata flushed with HTK solution, which prompted this review of transplanting HTK-flushed kidneys. We analyzed outcomes of deceased-donor kidneys flushed with HTK and UW solutions with a minimum of 12 months follow-up, excluding pediatric and multi-organ recipients. We evaluated patient and graft survival and rejection rates, variables that might constitute hazards to graft survival and renal function. Two-year patient survival, rejection, renal function and graft survival were not different, but early graft loss (<6 months) was worse in HTK-flushed kidneys (p < 0.03). A Cox analysis of donor grade, cold ischemic time, panel reactive antibodies (PRA), donor race, first vs. repeat transplant, rejection and flush solution showed that only HTK use predicted early graft loss (p < 0.04; relative risk = 3.24), almost exclusively attributable to primary non-function (HTK, n = 5 (6.30%); UW, n = 1 (0.65%); p = 0.02). Delayed graft function and early graft loss with HTK occurred only in lesser grade kidneys, suggesting it should be used with caution in marginal donors.     

Limited Survival of Rat Small Bowel Transplants Preserved in University of Wisconsin Solution for 48 Hours

We have previously shown that rat small bowel may successfully be transplanted after preservation for 24 hours. In this study, syngeneic rat small bowel transplants were studied by light microscopy and transmission electron microscopy during and after preservation in University of Wisconsin (UW) solution for 48 hours. A total of 6 transplants were carried out using a previously described, standardized technique. In most cases, the bowel appeared histologically well preserved at the end of the 48 hr storage period (prior to implantation). Upon revascularization, however, reperfusion injury was dramatic, with loss of villi and crypts and inflammatory cells in all layers. The bowel was abnormal grossly as well as microscopically. This injury was irreversible with persistently abnormal histology for up to 1 week in all but 2 cases.

We conclude that UW solution alone may allow satisfactory preservation of intestinal grafts for 48 hours only in isolated cases, and is therefore not adequate for predictable, satisfactory 48 hr preservation. Attempts to prevent reperfusion injury with oxygen-free radical scavengers are in progress.     

Comparison of HTK- and UW-solution for liver preservation tested in an orthotopic liver transplantation model in the pig

The aim of this experimental study was to compare the preservation potency of University of Wisconsin (UW) and HTK (Bretschneider) solutions in an orthotopic liver transplantation (OLT) model in pigs. Livers were harvested using an in situ perfusion technique, where organs were flushed with the solution being tested, stored on ice — cold storage (CS) — for 2 or 24 h and then transplanted. Parameters monitored were liver enzymes in serum, hepatic water content, high energy phosphates, nuclear magnetic resonance (NMR) relaxation time T2, light microscopy and bile production. CS for 24 h is an extreme in pig liver preservation and is not compatible with animal survival. Biopsies showed drastic morphological changes and grafts did not produce bile in either group. (Bile production 2 h CS: HTK, 5.6 ± 1.8 ml/h; UW, 4.7 ± 2.3 ml/h) Enzyme release after reperfusion (ASGOT, ?LDH) was higher in long-term preservation. Hepatic tissue water content significantly decreased during CS in UW preserved livers. Edema alter reperfusion (?H₂0: HTK 24 h = + 5.6%, UW 24 h= + 4.8%) and regeneration capacity after reperfusion (UW 2 h = 63%, HTK 2 h = 55%, UW 24 h = 30%, HTK 24 h = 30%) were not significantly different. However, we did not observe major differences in preservation potency between the solutions tested. Differences were correlated, rather, with length 9 time of CS, than with the solution used. Therefore, HTK solution seemed to be a low potassium containing alternative to UW solution.     

Comparison of University of Wisconsin (UW) and Eurocollins (EC) preservation solutions in a rat liver transplant model

The Eurocollins (EC) and University of Wisconsin (UW) preservation solutions were compared in a rat liver transplant model. After hepatectomy, 48 rat livers were flushed with either EC or UW preservation solution and were randomly assigned to 1, 12, 24, and 30 h of preservation at 4°C, resulting in eight groups each containing six livers. Following preservation, orthotopic liver transplantation with reconstruction of the hepatic artery was performed. The efficacy of the preservation solution was assessed at 48 h post-transplantation by survival histological features and aspartate transaminase assay (AST) values. None of the rats survived 30 h of liver preservation with EC whereas five out of six rats did with UW preservation. After 24 h of liver preservation, three of the six rats in the EC group survived, compared to all six rats in the UW group. Histological evidence of severe ischemia was found in both groups in all but one survivor (UW, 24 h). After 12 h of EC preservation, one rat died within 48 h and severe ischemic changes were found in the remaining five rats. Among the rats with 12 h of UW preservation, only two out of six showed ischemic changes, and all six rats survived beyond 48 h. Without preservation (1 h), ischemic damage was found in two out of six rats in each group and all rats survived. The median AST values were higher in the EC groups than in the UW groups; the difference became significant after 12-h preservation (EC 900 IU/l versus UW 465 IU/l) and 24-h preservation (EC 5220 IU/l versus UW 631 IU/l). However, the median AST value in the five surviving rats whose livers had been preserved for 30 h in UW climbed to 1880 (950–2240) IU/l.. We conclude that UW solution provides better long-term preservation than EC solution. However, even with UW solution, the observed mortality, the severity of ischemic changes, and the pronounced increase in the median AST value cast doubt upon the safety of liver preservation beyond 24 h.     

Increased Pancreatitis in Allografts Flushed with Histidine-Tryptophan-Ketoglutarate Solution: A Cautionary Tale

We reviewed pancreas transplantation outcomes after Histidine-Tryptophan-Ketoglutarate (HTK) and University of Wisconsin (UW) preservation solution use between 2001 and 2007 at two transplant centers. While equivalence has been claimed for kidney and liver transplant outcomes after the use of HTK or UW preservation solution, consensus has not been reached on equivalence when flushing pancreata. Others have reported comparable patient and graft survival rates, but found an association between the use of HTK and an increase in the incidence of acute rejection and pancreatitis. In reviewing our experiences, we found in pancreata flushed with HTK a higher incidence of postoperative complications including graft pancreatitis, use of octreotide and a decreased rate of insulin-independence at hospital discharge. These findings prompted us to critically review our centers' experience to determine if there is a basis for suspecting a causal relationship.     

A comparison of histadine lactobionate solution with University of Wisconsin solution for rat liver and heart preservation

We developed a new solution mainly composed of Na-lactobionate and histidine (HL) and compared the effectiveness of this solution with that of University of Wisconsin (UW) solution using orthotopic liver and heterotopic heart transplantation in rats. The new solution has a higher sodium content and a lower potassium content (Na, 90 mEq/l; K, 45 mEq/l) than UW. Hydroxyethyl starch, adenosine, dexamethasone and insulin are not included. Buffering capacity is increased by adding histidine (90 mm/l) together with KH₂PO₄ (20 mm/l). Rat liver was perserved in either UW or HL solution hypothermically for 24 h and then transplanted orthotopically into the recipient rat. The heart was preserved in either solution for 18 h and transplanted heterotopically into the recipient rat. The 1-week survival rate for rats receiving livers preserved in UW for 24 h at 4°C was 29% (5/17). In contrast, the new solution (HL) gave a 78% (11/14) survival rate (P < 0.01). The 1-week heart graft survival rate, using UW solution was 50% (3/6), following 18-h cold preservation, whereas all hearts (7/7) continued to beat for over a week using new HL solution (P < 0.05). These results demonstrated that the new HL solution, with a substantial buffering capacity, was superior to UW solution in rat liver and heart preservation.     

自制KYL液和UW液保存大鼠肝脏效果的比较

目的比较自制的KYL液和UW液对大鼠肝脏的保存效果。方法采用大鼠肝脏非循环离体灌注模型(noncirculatedisolatedperfusionofratliver),随机以KYL液和UW液对大鼠肝脏保存0、4、8、16、24和48h,记录胆汁流出量,测定灌注流出液天冬氨酸转氨酶(AST)、丙氨酸转氨酶(ALT)、乳酸脱氢酶(LDH)和氧自由基代谢产物丙二醛(MDA)及超氧化物歧化酶(SOD)含量,检测肝细胞内钙离子浓度,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液保存的大鼠肝脏在保存16h以内各时相胆汁流出量均较UW液保存者高(P<0.01),灌注流出液AST、ALT和LDH含量与UW液保存者相近,肝细胞内钙离子浓度较UW液保存者低(P<0.01);KYL组保存24及48h时,MDA含量低于UW组,SOD含量高于UW组(P<0.01);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,提示KYL保存与UW液一样对大鼠肝脏具有保护作用。结论自制的KYL液对大鼠肝脏的保存效果总体上与UW液相当,在再灌注后肝细胞胆汁分泌方面和钙拮抗方面略优于UW液,而在防止细胞水肿方面较UW液稍差。     

Postoperative recovery of mitochondrial function of the human liver graft procured and preserved with University of Wisconsin (UW) solution

Changes in arterial blood ketone body ratio (KBR) were investigated in 47 human liver transplantations. Of the 20 grafts preserved with University of Wisconsin (UW) solution, 10 had a cold preservation period of less than 10 h (UWS group) and 10 of more than 10 h (UWL group). In 27 other cases, grafts were preserved with EuroCollins (EC) solution for less than 10 h (EC group). In the EC group, KBR increased over 0.7 within 6 h after reperfusion of the graft in 17 cases (63%) and within 24 h in 7 cases (26%). In the 3 other cases, KBR failed to recover, and these patients underwent retransplantation. In the UW group, KBR recovered within 6 h in 13 cases (65%) and within 24 h in 7 cases (35%). There were no significant differences between the UWS and UWL groups. It is shown that the mitochondrial function of liver grafts preserved with UW solution can be well maintained even after extended preservation periods of more than 10 h.     

The impact of liver preservation in HTK and UW solution on microcirculation after liver transplantation

Severe microcirculatory disturbances due to endothelial cell damage and leukocyte adherence during reperfusion of transplanted livers are considered to contribute to early graft failure. Since the degree of reperfusion injury after liver transplantation depends on the length of preservation time and the solution used for preservation, the aim of our study was to assess three solutions with respect to microvascular perfusion and leukocyte adhesion. Therefore, rat livers were stored up to 24 h in Euro-Collins (EC), University of Wisconsin (UW), or histidin-tryphtophan-ketoglutarate (HTK) solutions prior to orthotopic transplantation. The livers were studied in situ 60 min postoperatively using intravital fluorescence video microscopy. Using simple syringe flushing (10 ml), sinusoidal perfusion decreased below 50% in EC preserved livers after 8 h preservation, in HTK preserved livers after 16 h preservation, and remained higher than 70% in livers preserved in UW up to 24 h. Permanent adhesion of leukocytes was increased more rapidly in organs after 1, 8, 16, and 24 h preservation in HTK (16%, 15%, 34%, and 49.7% ± 4.7%) compared to those preserved in UW (15%, 18%, 17%; and 32.7% ± 3.3%; P < 0.05). Using a 10-fold volumn of the organ weight of HTK solution during the harvesting procedure, with an 8 min equilibration period, sinusoidal perfusion (39.6 ± 4.7%) and leukocyte adhesion (42.7 ± 3.1%) were not improved after 24 h. In contrast, equilibration with a volumn of approximately 40-times the liver weight improved sinusoidal perfusion (70.8% ± 2.7%; P < 0.01) and leukocyte adhesion (24.9% ± 3.1%; P < 0.01) significantly. Thus, using HTK solution, simple flushing prior to long-term cold storage resulted in microcirculatory disturbances when compared to UW solution. Larger volumns of HTK solution with an additional equilibration period of 8 min, however, reduced leukocyte adhesion and improved sinusoidal perfusion to a similar degree as UW solution.