Histidine-tryptophan-ketoglutarate Research Articles

Inhibition of High Mobility Group Box 1–Toll-Like Receptor-4 Signaling by Glycyrrhizin Contributes to the Attenuation of Cold Ischemic Injury of Liver in a Rat Model

BackgroundCold ischemic injury in liver storage is an important issue pertaining to liver transplantation. Glycyrrhizin (GL), the glycoconjugated triterpene produced by the root of the licorice plant, has been used to treat chronic hepatitis; however, its function against cold ischemia injury remains unknown. MethodsLivers from Wistar rats were reperfused at 37°C for 60 minutes either immediately or after 24 hours of cold storage in histidine–tryptophan–ketoglutarate (HTK) solution containing different concentrations of GL (n = 30 for each group). Bile and lactate dehydrogenase (LDH) levels in the effluent perfusates were determined. Apoptotic cells, high mobility group box 1 (HMGB1), Toll-like receptor 4 (TLR4), and nuclear factor (NF)-κB in liver grafts were assessed. The levels of inflammatory mediators (tumor necrosis factor [TNF]-α, interleukin [IL]-6) in the effluent perfusates were measured. ResultsAddition of GL to HTK solution significantly attenuated ischemic injury during reperfusion in a dose-dependent way, as evidenced by the lower liver injury scores, lower LDH leakage, and increased bile secretion. After reperfusion, livers stored in HTK solution containing GL had decreased expression of HMGB1, TLR4, and NF-κB, and less apoptosis compared with those stored without GL. The levels of TNF-α and IL-6 in the effluent were also decreased when stored in GL-containing HTK solution. ConclusionThe addition of GL to HTK solution attenuates cold ischemic injury during cold storage and the mechanism is at least partially attributable to the inhibition of TLR4 signaling.

Donor pretreatment with adenosine monophosphate-activated protein kinase activator protects cardiac grafts from cold ischaemia/reperfusion injury.

Adenosine monophosphate-activated protein kinase (AMPK) is a master regulator of energy metabolism and has been shown to be protective in ischaemia/reperfusion injury (IRI). We hypothesized that preactivation of AMPK with an activator before donor heart procurement could protect heart grafts from cold IRI. Donor Sprague-Dawley rats were injected intravenously with AMPK activator 5-amino-imidazole-4-carboxamide ribonucleotide (AICAR) or vehicle 30 min before heart procurement. Heart grafts were then preserved in histidine-tryptophan-ketoglutarate (HTK) solution at 4°C for 8 h. After preservation, grafts were immediately mounted on the Langendorff perfusion system and perfused with Krebs-Henseleit buffer at 37°C for 1 h. Adenosine triphosphate (ATP) and malondialdehyde (MDA) content in graft tissue were quantified post-preservation and post-reperfusion. After reperfusion, isolated heart function was assessed using a pressure transducer; cumulative release of creatine kinase (CK) and lactate dehydrogenase (LDH) into the perfusate was measured to assess cardiomyocyte necrosis; ultrastructural changes in the mitochondria of the grafts were examined using transmission electron microscopy (TEM). After preservation, myocardial ATP content in the pretreated hearts was significantly higher than in the control hearts (3.247 ± 0.3034 vs 1.817 ± 0.2533 µmol/g protein; P < 0.05). AICAR-pretreated heart grafts exhibited significantly higher coronary flow (9.667 ± 0.3159 vs 8.033 ± 0.2459 ml/min; P < 0.05) and left ventricular developing pressure (58.67 ± 2.894 vs 42.67 ± 3.333 mmHg; P < 0.05) than the vehicle treated after reperfusion. Cumulative release of CK (300.0 ± 25.30 vs 431.7 ± 42.39 U/l; P < 0.05) and LDH (228.0 ± 16.68 vs 366.8 ± 57.41 U/l; P < 0.05) in the perfusate was significantly lower in the AICAR-pretreated group than that in the control group. Myocardial MDA content was also reduced in the pretreated group (0.5167 ± 0.1046 vs 0.9333 ± 0.1333 nmol/mg protein; P < 0.05). TEM suggested that the mitochondrial structure of AICAR-pretreated hearts was much better preserved. Moreover, AICAR-pretreated hearts significantly diminished cytosolic cytochrome c release after reperfusion. This study demonstrates that pretreatment with AMPK activator AICAR significantly protects heart grafts from extended cold IRI. This novel protocol may be useful and feasible in clinical heart transplantation.

Influence of a modified preservation solution in kidney transplantation: A comparative experimental study in a porcine model

Currently, due to lack of optimal donors, more marginal organs are transplanted. Therefore, there is a high interest to ameliorate preischemic organ preservation, especially for critical donor organs. In this regard, a new histidine-tryptophane ketoglutarate (HTK-N) solution has been designed and its protective efficacy was compared with the standard preservation solutions-University of Wisconsin solution and standard HTK or Custodiol (Bretschneider's solution). Seventy-two landrace pigs were included into the study, as donors and recipients. The donor kidneys were perfused during explantation with cold University of Wisconsin solution (n=12), standard HTK (n=12), or HTK-N solutions (n=12), kept in the respective preservation solution at 4°C for 30 hours, implanted in the recipient pigs, and reperfused. The pigs survived in daily control for 7 days. The serum creatinine and blood urea nitrogen were assessed in pre- and postreperfusion phase on the 3rd day and 7th day posttransplantation. Additionally, tissue samples were taken to analyze the histopathological degree of tubular injury and regeneration before and after reperfusion. The three preservation groups were comparable in age, body weight, and hemodynamic parameters. According to statistical proof, they differed in none of the control parameters. Although the new preservation HTK solution is in several points a well-thought-out modification of the standard HTK solution, its preservation efficacy, at least for kidney preservation in a pig model for 30 hours, seems to be comparable to the current used solutions. A real advantage, however, could be confirmed in clinical settings, where marginal organs may influence the clinical outcome.

Evaluation of the modified HTK solution in pancreas transplantation—An experimental model

One of the great challenges in pancreas transplantation is the ischemia reperfusion injury. It is mentioned that free oxygen and/or nitrogen radicals play a prominent role in this phase. To minimize this problem, a modified histidine-tryptophan-ketoglutarate (HTK) solution that contains modified antioxidants has been developed. Our aim was to evaluate this solution in improving the viability of the pancreas in comparison with standard HTK and University of Wisconsin (UW) solutions in a porcine model of pancreas transplantation. Twenty-three Landrace pigs were divided into three identical groups. After a 10-hour preservation time at 4°C, the pancreas was implanted in the organs of the recipients in a standardized manner. Serum parameters were assessed prior to and after implantation on the 1(st) postoperative day, 3(rd) postoperative day, and 7(th) postoperative day. Furthermore, three biopsies were taken: prior to and after reperfusion, and on Day 7 to assess the grafts. An analysis of serum glucose among the three groups showed no significant differences. Evaluation of the insulin levels showed no significant difference between the modified and standard HTK groups; however, differences between HTK and UW were significant (p=0.004 in favor of UW solutions). The histopathological results showed a trend of a higher grade of rejection of pancreas tissue in the UW group compared to both HTK groups. The modified HTK solution could preserve the pancreas for the preservation of the graft with similar results to those observed for standard solutions without any significant difference. The trend showed that the pathological finding in the UW group was not as good as that in the modified HTK and standard HTK groups.

Effect of TNF-alpha blockade on coagulopathy and endothelial cell activation in xenoperfused porcine kidneys.

Following pig-to-primate kidney transplantation, endothelial cell activation and xenogenic activation of the recipient's coagulation eventually leading to organ dysfunction and microthrombosis can be observed. In this study, we examined the effect of a TNF-receptor fusion protein (TNF-RFP) on endothelial cell activation and coagulopathy utilizing an appropriate ex vivo perfusion system. Using an ex vivo perfusion circuit based on C1-Inhibitor (C1-Inh) and low-dose heparin administration, we have analyzed consumptive coagulopathy following contact of human blood with porcine endothelium. Porcine kidneys were recovered following in situ cold perfusion with Histidine-tryptophan-ketoglutarate (HTK) organ preservation solution and were immediately connected to a perfusion circuit utilizing freshly drawn pooled porcine or human AB blood. The experiments were performed in three individual groups: autologous perfusion (n = 5), xenogenic perfusion without any further pharmacological intervention (n = 10), or with addition of TNF-RFP (n = 5). After perfusion, tissue samples were obtained for real-time PCR and immunohistological analyses. Endothelial cell activation was assessed by measuring the expression levels of E-selectin, ICAM-1, and VCAM-1. Kidney survival during organ perfusion with human blood, C1-Inh, and heparin, but without any further pharmacological intervention was 126 ± 78 min. Coagulopathy was observed with significantly elevated concentrations of D-dimer and thrombin-antithrombin complex (TAT), resulting in the formation of multiple microthrombi. Endothelial cell activation was pronounced, as shown by increased expression of E-selectin and VCAM-1. In contrast, pharmacological intervention with TNF-RFP prolonged organ survival to 240 ± 0 min (max. perfusion time; no difference to autologous control). Formation of microthrombi was slightly reduced, although not significantly, if compared to the xenogenic control. D-dimer and TAT were elevated at similar levels to the xenogenic control experiments. In contrast, endothelial cell activation, as shown by real-time PCR, was significantly reduced in the TNF-RFP group. We conclude that although coagulopathy was not affected, TNF-RFP is able to suppress inflammation occurring after xenoperfusion in this ex vivo perfusion model.

Protective effect of ischemic preconditioning on the jejunal graft mucosa injury during cold preservation

Protection of intestinal graft mucosa during cold preservation is still an unmet need in clinical practice, thus affecting the success of transplantation. The present study investigates the ability of two ischemic preconditioning (IPC) procedures to limit cold preservation injury. Three groups of Sprague–Dawley rats were recruited (n=11 each) as follows: the short IPC (SIPC) performed through 4cycles of mesenteric ischemia of 4min each followed by 10min of reperfusion, the long IPC (LIPC) obtained by 2 ischemic cycles of 12min each followed by 10min of reperfusion, and the control group (C) without IPC. Grafts were then stored in cold histidine–tryptophan–ketoglutarate solution and samples were taken at 0, 3, 6 and 9h lasting preservation. Both IPC groups showed an advanced degree of preservation with delayed development of graft mucosa damage, mainly in the crypt region. At the beginning of preservation, the graft mucosa in both IPC groups showed lower degree of mucosal injury index (MII) by 50% in comparison with C group. Specifically, a significant improvement of MII was observed after 3h of preservation in the LIPC group (p<0.05) in comparison with untreated C grafts. Significant atrophy of the intestinal mucosa in C group was found after 3h of preservation (p<0.01), in SIPC group the progress of atrophy was delayed to 6h (p<0.001), and in LIPC group only moderate decrease in that was found. A parallel increase of laminin expression with the MII rate after 6 and 9h of preservation in comparison with the level at time 0 was observed in all grafts (p<0.001 and p<0.01, respectively). In both IPC groups the apoptotic cell (AC) rate was significantly reduced at the beginning of cold preservation (p<0.05 both). Moreover, in both the SIPC and C groups, the progressive increase in MII rate connected with AC rate decrease was due to a predominance of necrosis. By contrast in the LIPC group, after an increase of nearly 50% in the AC rate at the 3rd hour, its level remained fairly constant during the further 6h of preservation, thus probably preventing necrosis and improving graft viability.

The effect of a hydrogen sulfide releasing molecule (Na2S) on the cold storage of livers from cardiac dead donor rats. A study in an ex vivo model

Liver transplantation is currently the preferred treatment option for end-stage liver disease. Donation after cardiac death was a common practice in the early years of organ donation before brain death criteria were established. Those organs were subjected to variable periods of warm ischemia that might intensify cold ischemia/reperfusion injuries. In the present, shortage of brain dead donors has led to the reassessment of organ donation after cardiac death.Since many cytoprotective roles have been describe for H2S during ischemia/reperfusion on a variety of tissues, we hypothesized that graft exposure to this bioactive gas might improve preservation of non-heart beating donated organs.Therefore, to establish a rat model of donation post-cardiac arrest and using this approach to judge H2S delivery effects on graft hypothermic preservation, were the main objectives of this investigation.Cardiopulmonary arrest was induced in sedated rats by overload of potassium (K+). Livers were surgically removed and subsequently stored in HTK Solution (Histidine–tryptophan–ketoglutarate) at 0–4°C. After 24h of hypothermic preservation, livers were rewarmed in an ex vivo model. Three experimental groups were established as follows: I – Livers procured before cardiac death and cold stored 24h in HTK (BCD); II – Livers procured after cardiac death (45min) and cold stored 24h in HTK (ACD); III – Livers procured after cardiac death (45min) and cold stored 24h in HTK+10μM Sodium Sulfide (Na2S) (ACD-SS). Data suggest that after 45min of warm ischemia, viability parameters assessed during reperfusion in the ex vivo model were significantly impaired. Real time PCR revealed that after ex vivo reperfusion there is an increased expression of HO-1 and TNF-α and a modest drop in Bcl-2 mRNA, which could be interpreted as the cellular response to the hypoxic insult sustained during warm ischemia.On the other hand, warm ischemic livers exposed to H2S during cold storage, improved microcirculation, morphology and viability parameters during ex vivo reperfusion and showed significant modulation of HO-1 mRNA expression.In conclusion, HTK supplementation with Na2S arose as a potential treatment to recover non-heart beating harvested organs. Furthermore, an appropriate model of cardiac dead liver donors was successfully developed.

Clinical Results of Different Myocardial Protection Techniques in Aortic Stenosis.

BackgroundHypertrophied myocardium is especially vulnerable to ischemic injury. This study aimed to compare the early and late clinical outcomes of three different methods of myocardial protection in patients with aortic stenosis.MethodsThis retrospective study included 225 consecutive patients (mean age, 65±10 years; 123 males) with severe aortic stenosis who underwent aortic valve replacement. Patients were excluded if they had coronary artery disease, an ejection fraction <50%, more than mild aortic regurgitation, or endocarditis. The patients were divided into three groups: group A, which was treated with antegrade and retrograde cold blood cardioplegia; group B, which was treated with antegrade crystalloid cardioplegia using histidine-tryptophan-ketoglutarate (HTK) solution; and group C, treated with retrograde cold blood cardioplegia.ResultsGroup A contained 70 patients (31.1%), group B contained 74 patients (32.9%), and group C contained 81 patients (36%). The three groups showed significant differences with regard to the proportion of patients with a New York Heart Association functional classification ≥III (p=0.035), N-terminal pro-brain natriuretic peptide levels (p=0.042), ejection fraction (p=0.035), left ventricular dimensions (p<0.001), left ventricular mass index (p<0.001), and right ventricular systolic pressure (p<0.001). Differences in cardiopulmonary bypass time (p=0.532) and aortic cross-clamp time (p=0.48) among the three groups were not statistically significant. During postoperative recovery, no significant differences were found regarding the use of inotropes (p=0.328), mechanical support (n=0), arrhythmias (atrial fibrillation, p=0.347; non-sustained ventricular tachycardia, p=0.1), and ventilator support time (p=0.162). No operative mortality occurred. Similarly, no significant differences were found in long-term outcomes.ConclusionAlthough the three groups showed some significant differences with regard to patient characteristics, both antegrade crystalloid cardioplegia with HTK solution and retrograde cold blood cardioplegia led to early and late clinical results similar to those achieved with combined antegrade and retrograde cold blood cardioplegia.

Comparison Between IGL-1 and HTK Preservation Solutions in Deceased Donor Liver Transplantation

The effectiveness of liver preservation solutions remains in evidence. Cold ischemia time, steatosis, expanded criterion donors, operational cost, and survival represent important roles in its success. In a prospective cohort study between August 2009 and April 2014, 178 patients were allocated into an Institut Georges Lopez – 1 (IGL-1) solution group (63.5%) or histidine-tryptophan-ketoglutarate (HTK) group (36.5%). There were no differences among recipient’s characteristics including age, skin color, gender, Model for End-stage Liver Disease score, acute rejection, cholestasis, and reperfusion syndrome incidences. Also, donors, age average, skin color, donor risk index, time in intensive care unit, hemodynamic variables, infections, and steatosis incidences were similar. The average cold ischemia time was 494 minutes in the IGL-1 group and 489 minutes in the HTK group (P = .77). Alanine aminotransferase and aspartate aminotransferase serum levels on the first postoperative day were 707 and 1185 mg/dL, respectively, with IGL-1 and 1298 and 2291 mg/dL, respectively, with HTK (P = .016) and similar at day 15 (P > .88). The incidence of delayed graft function was 4.5% with IGL-1 and 4.6% with HTK (P = .90). The incidence primary nonfunction was 2.7% with IGL-1 and 3.1% with HTK (P = .71). The incidence of perioperative death was 11.5% with IGL-1 and 13.8% with HTK (P = .94). The survival in 30 months was 86% in IGL-1 group and 82% in HTK group (P = .66). Both preservation solutions are efficient to liver transplantations with deceased donors. Major prospective trials are necessary to evaluate each preservation solution’s particularities. The preservation solution availability in each transplantation center must guide its use at the present moment.

Preservation solutions used during abdominal transplantation: Current status and outcomes

Organ preservation remains an important contributing factor to graft and patient outcomes. During donor organ procurement and transportation, cellular injury is mitigated through the use of preservation solutions in conjunction with hypothermia. Various preservation solutions and protocols exist with widespread variability among transplant centers. In this review of abdominal organ preservation solutions, evolution of transplantation and graft preservation are discussed followed by classification of preservation solutions according to the composition of electrolytes, impermeants, buffers, antioxidants, and energy precursors. Lastly, pertinent clinical studies in the setting of hepatic, renal, pancreas, and intestinal transplantation are reviewed for patient and graft survival as well as financial considerations. In liver transplants there may be some benefit with the use of histidine-tryptophan-ketoglutarate (HTK) over University of Wisconsin solution in terms of biliary complications and potential cost savings. Renal grafts may experience increased initial graft dysfunction with the use of Euro-Collins thereby dissuading its use in support of HTK which can lead to substantial cost savings. University of Wisconsin solution and Celsior are favored in pancreas transplants given the concern for pancreatitis and graft thrombosis associated with HTK. No difference was observed with preservation solutions with respect to graft and patient survival in liver, renal, and pancreas transplants. Studies involving intestinal transplants are sparse but University of Wisconsin solution infused intraluminally in combination with an intra-vascular washout is a reasonable option until further evidence can be generated. Available literature can be used to ameliorate extensive variation across centers while potentially minimizing graft dysfunction and improving associated costs.

Histidine-tryptophan-ketoglutarate solution with added ebselen augments myocardial protection in neonatal porcine hearts undergoing ischemia/reperfusion.

Whether modified histidine-tryptophan-ketoglutarate (HTK) solution offers myocardial protection to newborn heart has not been documented. The purpose of this study was to compare myocardial protection using HTK added by ebselen with HTK in a piglet model of cardiopulmonary bypass (CPB). Fifteen piglets were randomly assigned to three groups: the control group (C group, n = 5), HTK solution group (HTK group, n = 5), and HTK added by 10 nM ebselen group (HTK+E group, n = 5). Animals in the two experimental groups were placed on hypothermic CPB, after which the ascending aorta had been clamped for 2 h. The control animals underwent normothermic CPB without cardiac arrest. Myocardial antioxidant activities, myocytes apoptosis and mitochondrial structures, as well as the release of cytochrome c and the expression of Bax, Bcl-2, and HSP72 protein in myocardium were measured. Increased myocardial superoxide dismutase (SOD) and Mn-SOD activities, decreased TUNEL-positive cells, and reduced release of cytochrome c were noted in the HTK+E group compared with those in the HTK group (P = 0.021, P = 0.020, P = 0.045, and P = 0.010, respectively). The Bax/Bcl-2 ratio in the HTK group was significantly higher than that in the C group (P = 0.024). The expression of HSP72 protein and mRNA in the HTK+E group was higher than that in the HTK group (P = 0.039 and P = 0.035, respectively). Mitochondrial score under electron microscope in the HTK+E group was lower than that in the HTK group (P = 0.047). Improved antioxidant defense, reduced myocytes apoptosis, and better preserved mitochondrial structure were observed in the HTK+E group. Ebselen added to HTK provides better myocardioprotection to HTK solution for the neonatal heart.

Detailed statistical analysis plan for the pulmonary protection trial.

BackgroundPulmonary dysfunction complicates cardiac surgery that includes cardiopulmonary bypass. The pulmonary protection trial evaluates effect of pulmonary perfusion on pulmonary function in patients suffering from chronic obstructive pulmonary disease. This paper presents the statistical plan for the main publication to avoid risk of outcome reporting bias, selective reporting, and data-driven results as an update to the published design and method for the trial.ResultsThe pulmonary protection trial is a randomized, parallel group clinical trial that assesses the effect of pulmonary perfusion with oxygenated blood or Custodiol™ HTK (histidine-tryptophan-ketoglutarate) solution versus no pulmonary perfusion in 90 chronic obstructive pulmonary disease patients. Patients, the statistician, and the conclusion drawers are blinded to intervention allocation. The primary outcome is the oxygenation index from 10 to 15 minutes after the end of cardiopulmonary bypass until 24 hours thereafter. Secondary outcome measures are oral tracheal intubation time, days alive outside the intensive care unit, days alive outside the hospital, and 30- and 90-day mortality, and one or more of the following selected serious adverse events: pneumothorax or pleural effusion requiring drainage, major bleeding, reoperation, severe infection, cerebral event, hyperkaliemia, acute myocardial infarction, cardiac arrhythmia, renal replacement therapy, and readmission for a respiratory-related problem.ConclusionsThe pulmonary protection trial investigates the effect of pulmonary perfusion during cardiopulmonary bypass in chronic obstructive pulmonary disease patients. A preserved oxygenation index following pulmonary perfusion may indicate an effect and inspire to a multicenter confirmatory trial to assess a more clinically relevant outcome.Trial registrationClinicalTrials.gov identifier: NCT01614951, registered on 6 June 2012Electronic supplementary materialThe online version of this article (doi:10.1186/1745-6215-15-510) contains supplementary material, which is available to authorized users.

Use of IGL–1 Preservation Solution in Liver Transplantation

University of Wisconsin (UW) solution has been known as the standard solution for liver graft preservation. Alternative preservation solutions have been used in liver transplantation, such as histidine-tryptophan-ketoglutarate (HTK) and Celsior solution. Institut Georges Lopez-1 (IGL--1) is a new preservation solution with lower potassium and lower viscosity than UW solution that has recently been used in liver transplant. Data from 178 patients who received transplants from August 2008 to June 2013 at Hospital Santa Isabel, Blumenau, Brazil, were analyzed. All patients received grafts from brain death donors. In November 2011 we started to use IGL--1 as an alternate preservation solution. Therefore, 53 patients using IGL--1 preserved grafts were compared to 125 using HTK solution. The donor age in the HTK group ranged from 11–77 years, with a mean of 43.4 ± 4.8. In the IGL--1 group donor age ranged from 9–62 years, with a mean of 35.8 ± 4.5. Cold ischemia time in the HTK group ranged from 85–1145 minutes, mean 443.5 ± 183.5 minutes. In the IGL--1 group, cold ischemia time ranged from 85–670 minutes, mean 329.3 ± 134.8 minutes. The overall operative mortality rate was 14% (25 patients); in the HTK group, 14.4% (18 patients); and in the IGL--1 group, 13.4% (7 patients). One graft in the HTK group presented with primary non-function (PNF), 0.7%; there were none in the IGL--1 group. In our study, IGL--1 has been shown to be safe to use as a preservation solution for liver transplantation. Early post-transplant graft function was comparable to that observed with HTK solution, although a tendency for lower alanine aminotransferase levels was noticed. IGL--1 has been shown to be safe, cost efficient, and an effective preservation solution.

Pretreatment of the Donor with AICAR Significantly Protects Rat Heart Graft from Prolonged Cold Ischemia/Reperfusion Injury in an Isolated Model.

Purpose: To investigate whether pretreat donor rat with AMP-activated protein kinase (AMPK) activator AICAR can reduce heart graft injury after static, prolonged cold preservation and reperfusion in an isolated model. Methods: Eighteen Sprague-Dawley(SD) heart donor rats were equally divided into two groups: AICAR pretreatment group(AICAR group, n=9) and normal saline pretreatment group(Vehicle group, n=9). After the hearts were arrested with Histidine-Tryptophan-Ketoglutarate(HTK) solution, they were excised and preserved in HTK solution for 8 hours at 4 <sup style=“font-family: Arial, sans-serif;”>o[/sup]C. After cold preservation, hearts were reperfused for 1hr in an Langendorff model, concerned parameters were examined during and after reperfusion. Result: AICAR pretreated heart showed significantly higher left ventricular developing pressure(LVDP), heart rate(HR), coronary flow(CF) than vehicle pretreated group. Caspase 3 activity and percentage of TUNEL-positive cells were significantly reduced in AICAR pretreated group. Oxidative parameter 8-hydroxy-2′-deoxyguanosine(8-OHdG) and malondialdehyde (MDA) were also significantly decreased in AICAR pretreated group. Moreover, AICAR pretreatment significantly diminished cystolic cytochrome C release. Conclusion: Pretreatment of the donor with AICAR significantly protects heart grafts from prolonged cold ischemia/reperfusion injury. This protocol may be useful and feasible in clinical heart transplantation.

Preservation solutions for cardiac and pulmonary donor grafts: a review of the current literature.

Hypothermic preservation of donor grafts is imperative to ameliorate ischemia related cellular damage prior to organ transplantation. Numerous solutions are in existence with widespread variability among transplant centers as to a consensus regarding the optimal preservation solution. Here, we present a concise review of pertinent preservation studies involving cardiac and pulmonary allografts in an attempt to minimize the variability among institutions and potentially improve graft and patient survival. A biochemical comparison of common preservation solutions was undertaken with an emphasis on Euro Collins (EC), University of Wisconsin (UW), histidine-tryptophan-ketoglutarate (HTK), Celsior (CEL), Perfadex (PER), Papworth, and Plegisol. An appraisal of the literature ensued containing the aforementioned preservation solutions in the setting of cardiac and pulmonary transplantation. Available evidence supports UW solution as the preservation solution of choice for cardiac transplants with encouraging outcomes relative to notable contenders such as CEL. Despite its success in the setting of cardiac transplantation, its use in pulmonary transplantation remains suboptimal and improved outcomes may be seen with PER. Together, we suggest, based on the literature that the use of UW solution and PER for cardiac and pulmonary transplants, respectively may improve transplant outcomes such as graft and patient survival.

Myocardial injury following aortic valve replacement for severe aortic stenosis: risk factor of postoperative myocardial injury and its impact on long-term outcomes.

BackgroundAs hypertrophied myocardium predisposes the patient to decreased tolerance to ischemia and increased reperfusion injury, myocardial protection is of utmost importance in patients undergoing aortic valve replacement (AVR) for severe aortic valve stenosis (AS).MethodsConsecutive 314 patients (mean age, 62.5±10.8 years; 143 females) with severe AS undergoing isolated AVR were included. Postoperative myocardial injury (PMI) was defined as 1) maximum postoperative creatinine kinase isoenzyme MB or troponin-I levels ≥10 times of reference, 2) postoperative low cardiac output syndrome or episodes of ventricular arrhythmia, or 3) left ventricular ejection fraction of less than 55% and decrease in left ventricle (LV) ejection fraction of more than 20% of the baseline value.ResultsThere were 90 patients (28.7%) who developed PMI. There were five cases of early death (1.6%), all of whom had PMI. On multivariable analysis, the use of histidine-tryptophan-ketoglutarate (HTK) solution instead of blood cardioplegia (odds ratio [OR], 3.06; 95% confidence interval [CI], 1.63 to 5.77; p=0.001), greater LV mass (OR, 1.04; 95% CI, 1.01 to 1.07; p=0.007), and increased cardiac ischemic time (OR, 1.13; 95% CI, 1.05 to 1.22; p<0.001) were independent predictors for PMI. Patients who had PMI showed significantly inferior long-term survival than those without PMI (p=0.049).ConclusionPMI occurred in a considerable proportion of patients undergoing AVR for severe AS and was associated with poor long-term survival. HTK cardioplegia, higher LV mass, and longer cardiac ischemic duration were suggested as predictors of myocardial injury.

Adult Porcine Islet Isolation Using a Ductal Preservation Method and Purification With a Density Gradient Composed of Histidine-Tryptophan-Ketoglutarate Solution and Iodixanol

BackgroundGiven the fragility of adult porcine islets, reduction of shearing stress in islet purification using histidine-tryptophan-ketoglutarate (HTK) solution and iodixanol could be an effective strategy. We examined the effect of ductal preservation with HTK solution and an islet purification protocol that utilizes HTK solution and iodixanol in adult porcine islet isolation. MethodsIslets were isolated with a modified Ricordi method using adult Prestige World Genetics (PWG) and Yucatan pigs. The discontinuous density gradient was composed of either HTK solution/iodixanol (n = 23, iodixanol group) or Hank's balanced salt solution (HBSS)/Ficoll (n = 17, Ficoll group). In the iodixanol group, ductal injection of HTK solution was performed before purification. ResultsIn PWG pigs, significantly higher islet yield after purification (3480 ± 214.2 islet equivalent [IEQ]/g, P = .003) and higher recovery rate (85.45% ± 3.49%, P = .0043) were obtained from the HTK/iodixanol group as compared to the HBSS/Ficoll group (1905 ± 323.2 IEQ/g, and 67.22% ± 4.77%, respectively). Similar results were obtained in Yucatan pigs with greater body weight. ConclusionDuctal preservation and iodixanol-based islet purification using HTK solution improved the yield of adult porcine islet isolation compared to the conventional method using HBSS and Ficoll. The results of this study support the feasibility of an adult porcine islet isolation protocol using HTK solution and iodixanol, which have the favorable physical properties.

Myocardial Protection in Donor Heart Preservation: A Comparison Between Bretschneider's Histidine–Tryptophan–Ketoglutarate Solution and Cold Blood Cardioplegia

BackgroundOptimal myocardial protection for donated hearts is crucial to improve outcomes of heart transplantation and reduce morbidity and mortality. This study aimed to compare the efficacy of myocardial protection using single dose of Bretschneider's histidine–tryptophan–ketoglutarate (HTK) solution and repeated doses of cold blood cardioplegia (CBC) in donor heart preservation. MethodsSixty-seven patients undergoing heart transplantation in Tri-Service General Hospital, Taipei, Taiwan between 2002 and 2012 were enrolled in this study. Patients were divided into an HTK group and a CBC group based on the preservation solution used to protect the donated hearts. The perioperative variables and postoperative outcomes were retrospectively reviewed. ResultsThere were no statistic differences about demographic data in donors and recipients between the 2 groups. There were no significant differences in postoperative cardiac enzymes, hemodynamic data, length of stay in intensive care, or 30-day mortality between the groups. The HTK group showed a trend of shorter pumping time (P = .091). Multivariate analyses reveal that the HTK group had higher postoperative inotropic score (P < .001) and shorter pumping time (P = .02). ConclusionsSingle dose of Bretschneider's HTK solution could effectively reduce pumping time and afford similar myocardial protection compared with repeated doses of CBC in the preservation of donated hearts.

Dose-ranging study of the performance of the natural oxygen transporter HEMO2 Life in organ preservation.

The intensity of ischemia-reperfusion injury of the donor organ during the preservation phase and after anastomosis is acknowledged as being a key factor for long-term graft outcome. We previously showed that the addition of 5 g/L of the natural oxygen carrier HEMO2 Life was beneficial for the cold static preservation of kidney grafts in both University of Wisconsin (UW) and histidine-tryptophan-ketoglutarate solutions. Herein, we refined these findings by evaluating HEMO2 Life at various dose levels in UW, both in vitro with endothelial cells and in vivo in a pig kidney autotransplantation preclinical model. We showed in vitro that cells were significantly better preserved with HEMO2 Life in a dose-dependent manner, with benefits in terms of survival, metabolic activity, and cellular integrity. In vivo, serum creatinine measurements at reperfusion confirmed the important benefits of HEMO2 Life treatment on function recovery at the dose levels of 1, 2, and 5 g/L. Likewise, histological analysis of kidney parenchyma biopsies from day 7 confirmed the superiority of HEMO2 Life-supplemented UW over UW alone, and there was no difference between the doses. Three months' follow-up confirmed the trend of the first 2 weeks, with creatinine and fibrosis levels similar to those in pretransplant kidneys.

Preservation solutions for static cold storage of abdominal allografts

To update the reader on the recent literature in liver, kidney, pancreas, and intestine static cold preservation, and to identify which solutions are most advantageous for each organ. The comparison of randomized trials of histidine-tryptophan-ketoglutarate (HTK), Celsior, and University of Wisconsin solutions has shown equivalent risk of delayed graft function after kidney transplantation. Similar outcomes have been observed after pancreas preservation with University of Wisconsin, HTK, and Celsior solution. In live-donor liver transplantation, University of Wisconsin and HTK solution have shown equivalent results, whereas in the recent trials of deceased-donor liver transplantation, University of Wisconsin, HTK, and Celsior solutions have shown equivalence. Contrary to the most clinical trials, national registry data in kidney, pancreas, and liver transplantation demonstrate more detrimental effects and earlier graft loss after preservation with HTK versus University of Wisconsin solution. Early outcomes after intestinal transplantation with University of Wisconsin or HTK solution have shown no significant difference and animal studies indicate intraluminal preservation may be beneficial. The University of Wisconsin solution is the standard criterion static cold preservation for the procurement of liver, kidney, pancreas, and intestine. University of Wisconsin, HTK, and Celsior solutions all provide similar allograft outcomes in most clinical trials, but subtle differences have become more apparent in the recent studies and registry reports.