Lung transplantation following controlled hypothermic storage with a portable lung preservation device: first multicenter European experience.

Introduction: Compared with traditional static ice storage, controlled hypothermic storage (CHS) at 4-10°C may attenuate cold-induced lung injury between procurement and implantation. In this study, we describe the first European lung transplant (LTx) experience with a portable CHS device. Methods: A prospective observational study was conducted of all consecutively performed LTx following CHS (11 November 2022 and 31 January 2024) at two European high-volume centers. The LUNGguard device was used for CHS. The preservation details, total ischemic time, and early postoperative outcomes are described. The data are presented as median (range: minimum-maximum) values. Results: A total of 36 patients underwent LTx (i.e., 33 bilateral, 2 single LTx, and 1 lobar). The median age was 61 (15-68) years; 58% of the patients were male; 28% of the transplantations had high-urgency status; and 22% were indicated as donation after circulatory death. In 47% of the patients, extracorporeal membrane oxygenation (ECMO) was used for perioperative support. The indications for using the CHS device were overnight bridging (n = 26), remote procurement (n = 4), rescue allocation (n = 2), logistics (n = 2), feasibility (n = 1), and extended-criteria donor (n = 1). The CHS temperature was 6.5°C (3.7°C-9.3°C). The preservation times were 11 h 18 (2 h 42-17 h 9) and 13 h 40 (4 h 5-19 h 36) for the first and second implanted lungs, respectively, whereas the total ischemic times were 13 h 38 (4 h 51-19 h 44) and 15 h 41 (5 h 54-22 h 48), respectively. The primary graft dysfunction grade 3 (PGD3) incidence rates were 33.3% within 72 h and 2.8% at 72 h. Intensive care unit stay was 8 (4-62) days, and the hospital stay was 28 (13-87) days. At the last follow-up [139 (7-446) days], three patients were still hospitalized. One patient died on postoperative day 7 due to ECMO failure. In-hospital Clavien-Dindo complications of 3b were observed in six (17%) patients, and 4a in seven (19%). Conclusion: CHS seems safe and feasible despite the high-risk recipient and donor profiles, as well as extended preservation times. PGD3 at 72 h was observed in 2.8% of the patients. This technology could postpone LTx to daytime working hours. Larger cohorts and longer-term outcomes are required to confirm these observations.

Impact of demographic factors on corneal donor recovery.

PURPOSE: Death-to-preservation time (DTP) is a commonly reported, but infrequently studied, measure of efficiency for the corneal tissue procurement process and is a key screening component for corneal tissue suitability for transplantation. It is unknown whether demographic factors such as race, age, or gender may affect DTP. METHODS: This retrospective cross-sectional study included all deceased-donor eye tissue collected by CorneaGen Eye Banks between June 1, 2012 and June 30, 2016. Exposure variables of race, age, and gender were independently analyzed with the outcome variable, DTP, using three simple linear regression analyzes. Associations were then confirmed by a multiple linear regression analysis within a single model. RESULTS: A total of 24,138 unique donors were identified from 48,207 donor eyes. Simple linear regression analysis showed that relative to White donors, Black and Hispanic donors were associated with a 2.40 h (95% CI 2.07-2.74 h, p < 0.001) and 2.48 h (95% CI 2.15-2.80 h, p < 0.001) longer mean DTP, respectively. DTP decreased with increasing age, at a rate of 30 min per every 10 years (95% CI 27-33 min, p < 0.001). Male donors were associated with a 35 min (95% CI 26-44 min, p < 0.001) longer DTP relative to female donors. A multiple linear regression confirmed the results of the three simple linear regressions. CONCLUSIONS: In a large cohort of corneal donors, non-White race, younger age, and male gender were associated with longer DTP.

Hypothermic oxygenated perfusion (HOPE) safely and effectively extends acceptable donor heart preservation times: Results of the Australian and New Zealand trial.

BACKGROUND: Cold static storage preservation of donor hearts for periods longer than 4 hours increases the risk of primary graft dysfunction (PGD). The aim of the study was to determine if hypothermic oxygenated perfusion (HOPE) could safely prolong the preservation time of donor hearts. METHODS: We conducted a nonrandomized, single arm, multicenter investigation of the effect of HOPE using the XVIVO Heart Preservation System on donor hearts with a projected preservation time of 6 to 8 hours on 30-day recipient survival and allograft function post-transplant. Each center completed 1 or 2 short preservation time followed by long preservation time cases. PGD was classified as occurring in the first 24 hours after transplantation or secondary graft dysfunction (SGD) occurring at any time with a clearly defined cause. Trial survival was compared with a comparator group based on data from the International Society of Heart and Lung Transplantation (ISHLT) Registry. RESULTS: We performed heart transplants using 7 short and 29 long preservation time donor hearts placed on the HOPE system. The mean preservation time for the long preservation time cases was 414 minutes, the longest being 8 hours and 47 minutes. There was 100% survival at 30 days. One long preservation time recipient developed PGD, and 1 developed SGD. One short preservation time patient developed SGD. Thirty day survival was superior to the ISHLT comparator group despite substantially longer preservation times in the trial patients. CONCLUSIONS: HOPE provides effective preservation out to preservation times of nearly 9 hours allowing retrieval from remote geographic locations.

Human platelet mitochondria improve the mitochondrial and cardiac function of donor heart.

Mitochondria transplantation emerges as an effective therapeutic strategy for ischemic-related diseases but the roles in the donor hearts for transplant remain unidentified. Here, we investigated whether the preservation of the donor heart with human platelet-derived mitochondria (pl-MT) could improve mitochondrial and cardiac function. Incubation with pl-MT resulted in the internalization of pl-MT and the enhancement of ATP production in primary cardiomyocytes. In addition, incubation of rat hearts with pl-MT ex vivo for 9 h clearly demonstrated pl-MT transfusion into the myocardium. Mitochondria isolated from the hearts incubated with pl-MT showed increased mitochondrial membrane potential and greater ATP synthase activity and citrate synthase activity. Importantly, the production of reactive oxygen species from cardiac mitochondria was not different with and without pl-MT incubation. Functionally, the heartbeat and the volume of coronary circulation perfusate were significantly increased in the Langendorff perfusion system and the viability of cardiomyocytes was increased from pl-MT hearts.Taken together, these results suggest that incubation with Pl-MT improves mitochondrial activity and maintains the cardiac function of rat hearts with prolonged preservation time. The study provides the proof of principle for pl-MT application as an enhancer of the donor heart.

Viability of Toxoplasma gondii tachyzoites in different conditions for parasite transportation.

Background and Aim: Toxoplasma gondii tachyzoite is the infective stage that causes acute infection, leading to severe toxoplasmosis. The tachyzoite stage has been extensively used for several inoculation purposes, including antigen production, immunological studies, nutrition mechanisms, and in vitro drug trials. The use of fresh tachyzoites is required for inoculation in either in vitro or in vivo studies. However, there is a lack of information on preserving live tachyzoites during transportation from laboratories to inoculation sites. Therefore, this study aimed to validate suitable preservative conditions for maintaining live parasites by determining the survival and viability of T. gondii tachyzoites on the basis of different media, temperatures, and incubation times. Materials and Methods: The free live T. gondii tachyzoites were evaluated on their viability when maintained in different media without 5% Carbon dioxide (CO2). The purified tachyzoites of the RH and PLK strains were individually suspended in normal saline (NS), phosphate-buffered saline (PBS), minimum essential medium (MEM), and MEM with 10% fetal bovine serum (MEM-FBS) and incubated for 6 h at ice-cold (IC; 3-9°C) and room temperature (RT; 25°C). Parasite survival was measured at the 0, 1st, 2nd, 3rd, 4th, 5th, and 6th h post-incubation using the trypan blue exclusion test. Results: The viability was in the range of 85.0%-91.0% for IC using NS and 81.0%-85.1% (IC) and 75.3%-77.5% (RT) using PBS. The viability was approximately 75.0%-83.0% (IC) and 70.0%-79.0% (RT) using MEM and MEM-FBS. There was a significant difference in the viability between the seven periods on the basis of one-way repeated Analysis of variance and Friedman analyses. Parasite survival slightly reduced (20.0%-30.0%) in NS and MEM-FBS at both temperatures during incubation. Notably, PBS could not support tachyzoite viability after 3 h post-incubation. Conclusion: NS was a suitable preservative for maintaining purified T. gondii tachyzoites during transportation at IC and RT without 5% CO2 supplementation. This could be a valuable medium for parasite transportation, especially when there is a large distance between the laboratory and inoculation site.

Influence of time to procurement, incubation and release of organ cultured donor corneas on graft failure after Descemet Stripping Automated Endothelial Keratoplasty.

PURPOSE: The aim of the present study was to investigate whether the time from death to procurement, to preservation or the storage time of donor corneas preserved in organ culture influenced the clinical outcome of patients undergoing Descemet stripping automated endothelial keratoplasty (DSAEK) for Fuchs endothelial keratoplasty. METHODS: We conducted a registry-based study on 776 patients undergoing DSAEK. Data on time from donor death to cornea retrieval (DRT), time from death to preservation (DPT), the preservation time and donor cornea characteristics: age, sex and endothelial cell density (ECD) at the time of release for surgery, were extracted from The Danish Cornea Bank Registry. Data on recipient follow-up were collected from a corneal graft registry. The primary outcome was presence of graft failure within a period from 2 months to 2 years after surgery. Secondary outcomes were DRT, DPT, ECD ≤2300 and gender mismatch between donor and recipient. RESULTS: Graft failure occurred in 26 patients. The mean preservation time for failed grafts was 34.1 ± 10.0 days (mean ± SD) and 27.3 ± 10.6 days (mean ± SD) for the clear, functional grafts at the 2-year follow-up. A preservation time of >29 days compared with ≤29 days was associated with a lower survival (HR 2.33, 95% CI on 1.06-5.14, p = 0.036) and an increased risk of graft failure (RR 1.53, 95% CI on 1.11-2.10, p = 0.009). For the secondary outcome variables, no difference in the risk of graft failure was observed and did not appear to impact the survival rate of DSAEK patients. CONCLUSION: Preservation time of donor cornea was associated with graft survival and a prolonged preservation time of more than 4 weeks seemed to lower the 2-year survival.

Hypothermic oxygenated machine perfusion for extended criteria donor allografts: Preliminary experience with extended organ preservation times in the setting of organ reallocation.

BACKGROUND: In times of critical organ shortage, poor organ pool utilization and increased use of extended-criteria donor (ECD) allografts remain a major problem. Hypothermic oxygenated machine perfusion (HOPE) has emerged as a promising and feasible strategy in ECD liver transplantation (LT). However, potential safety limits regarding the duration of perfusion are yet to be explored. Besides marginal allograft quality (steatosis), prolonged cold ischemia time remains the most important factor for a high number of liver allografts being declined for transplantation. PATIENTS AND METHODS: Two ECD-allografts were each allocated to two recipients, who proved to be unsuitable to receive the assigned allograft upon arrival at the transplant center. The organs were reallocated by Eurotransplant and accepted by our center for two different backup patients. During that time, HOPE was commenced and continued until the recipient hepatectomy was completed. Postoperative allograft function was assessed by serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin, and International Normalized Ratio. Incidence of early allograft dysfunction (EAD), postoperative complications, and length of hospital stay were analyzed. RESULTS: HOPE was applied for 4 h 35 min and 4 h 20 min, resulting in a total cold preservation time of 17 h 29 min and 15 h 20 min, respectively. Both recipients displayed decreasing serum transaminases and bilirubin levels postoperatively. No EAD or major postoperative complications occurred in either patient. Serum ALT and AST levels were within the normal range at discharge. CONCLUSIONS: Extended HOPE enables the safe extension of preservation time for up to 18 h in human LT. End-ischemic HOPE may significantly improve organ pool utilization, while simultaneously facilitating operating room logistics and preventing organ injury.

Cornea Procurement and Processing up to 72 Hours: No Risk for Cornea Transplant Quality.

BACKGROUND: The realization of tissue donations is bound to a tight timeframe. Depending on the type of tissue, time limits are specified within which the donation must be procured and processed. Otherwise, there is a risk of tissue quality loss with increasing time intervals from cardiovascular arrest. According to the European Directorate for the Quality of Medicines and HealthCare (EDQM) guide, cornea must be procured and processed within 72 h after death. The question arises whether this time interval has an influence on the quality of transplanted tissues and how it affects the accomplishment of tissue donations. METHODS: In order to obtain information on this, the numbers of tissue donations in the network of the German Society for Tissue Transplantation (DGFG) were evaluated as a function of the death to retrieval time (DRT) as well as the death to preservation time (DPT). For this purpose, 21,454 database entries of cornea donations made in the period from 2014 to 2018 were included. RESULTS: The results show that nearly 50% of donations realized in the DGFG network could be processed only 48 h or later after cardiovascular death due to the opt-in regulation in Germany. For these donations, there seems to be a higher discard rate compared to donations taken earlier. Nevertheless, there is a transplantation rate for these grafts of more than 65%, which is comparable to average transplantation rates stated in the literature. CONCLUSION: All corneas finally selected for transplantation must meet the specified quality parameters. Since this naturally also applies to transplants that could only be procured at later time points, it can be concluded that DPT up to 72 h for corneal tissue is adequate and has no influence on the quality of corneas that are ultimately transplanted.

Pancreas preservation time as a predictor of prolonged hospital stay after pancreas transplantation.

OBJECTIVE: Length of hospital stay is a sensitive indicator of short-term prognosis. In this retrospective study, we investigated how pancreas preservation time affects length of hospital stay after pancreas transplantation. METHODS: Patients receiving pancreas transplantation (1998.7-2018.6) were identified from the Scientific Registry of Transplant Recipients database and grouped according to pancreas preservation time. We analyzed the relationship of pancreas preservation time with graft and patient survival and prolonged length of stay (PLOS; i.e., hospital stay ≥20 days). RESULTS: We included 18,099 pancreas transplants in the survival analysis. Pancreas preservation time >20 hours had a significantly higher risk of graft failure than 8 to 12 hours. Pancreas preservation time was not significantly associated with patient survival. We included 17,567 pancreas transplants in the analysis for PLOS. Compared with 8 to 12 hours, pancreas preservation time >12 hours had a significantly higher PLOS risk, which increased with increased pancreas preservation time. In simultaneous pancreas-kidney transplantation, we also found that pancreas preservation time was positively associated with PLOS risk with pancreas preservation time >12 hours. CONCLUSION: Pancreas preservation time is a sensitive predictor of PLOS. Transplant centers should minimize pancreas preservation time to optimize patient outcomes.

[Effect of fecal bacterial preservation time on the outcomes of fecal microbiota transplantation for slow transit constipation].

Objective: To investigate the effect of different fecal bacterial preservation time on the efficacy and complications of FMT. Methods: A retrospective cohort study was carried out. Clinical data of 483 patients with slow transit constipation undergoing voluntary FMT at Intestinal Microecology Diagnosis and Treatment Center from August 2017 to October 2019 were retrospectively collected. According to the storage time of fecal bacterial samples used in FMT treatment, the cases were divided into fresh bacterial solution (n=29), bacterial solution stored at -80℃ for 1 week (n=187), 1 month (n=121), 3 months (n=89), 6 months (n=38), and 12 months (n=19). The total number of complete bowel movement, Wexner constipation score, gastrointestinal quality of life index (GIQLI), FMT satisfaction score and related adverse reactions were summarized and compared among groups 1 week and 1 month after FMT treatment. Results: There were no statistically significant differences in the baseline data of patients among different bacterial solution storage time (all P>0.05). After 1 month of treatment, the overall frequency of defecation of all the patients was (3.83 ± 1.22) times/week, Wexner constipation score was (6.74 ± 3.56) points, GIQLI score was (108.76 ± 15.38) points, clinical cure rate was 57.8% (279/483). The improvement rate was 66.3% (320/483), and the treatment satisfaction was (3.85 ± 0.93) points. No severe FMT-associated complication and death were observed during treatment and follow-up period. FMT-related adverse events occurred in 115 cases (23.8%), including nausea in 25 cases (5.2%), vomiting in 13 (2.7%), diarrhea in 21 (4.3%), abdominal pain in 16 (3.3%), abdominal distension in 33 (6.8%), sore throat in 56 (11.6%) and fever in 16(3.3%), all of which relieved after symptomatic treatment. There were no statistically significant differences in the number of defecations, Wexner constipation scores, and GIQLI scores before FMT, 1 week and 1 month after FMT treatment among different bacterial solution storage groups (all P>0.05). Differences of clinical cure rate, clinical improvement rate, and treatment satisfaction of patients 1 week and 1 month after treatment were not statistically significant (all P>0.05). Among the groups, differences in the overall complications and types of complications after FMT treatment were not statistically significant (all P>0.05). Conclusions: FMT is safe and effective in the treatment of slow transit constipation. Fresh fecal bacterial samples or fecal bacterial samples frozen at -80℃ for 1 year can be safely applied to FMT for the treatment of slow transit constipation, with stable short-term efficacy and without serious adverse reactions.

NaCl treatment markedly enhanced pollen viability and pollen preservation time of euhalophyte Suaeda salsa via up regulation of pollen development-related genes.

Vegetable growth of halophytes has significantly increased through moderate salinity. However, little is known about the reproductive traits of euhalophytes. Male reproduction is pivotal for fertilization and seed production and sensitive to abiotic stressors. The pollen viability and pollen longevity of Suaeda salsa treated with 0 and 200 mM of NaCl were evaluated. It was revealed that the pollen size of S. salsa treated with NaCl was significantly bigger than that in controls. Furthermore, the pollen viability of S. salsa plants treated with NaCl was also significantly higher than that of control after 8 h of the pollens were collected (from 10 to 27 h). The pollen viability of NaCl-treated plants in the field could be maintained for 8 h (from 07:00 to 15:00) in sunny days, which was 1 h longer than that of control plants (from 07:00 to 14:00). Meanwhile, the pollen preservation time of NaCl-treated plants was 16 h at room temperature, which was 8 h longer than that of control plants. Genes related to pollen development, such as SsPRK3, SsPRK4, and SsLRX, exhibited high expression in the flowers of NaCl-treated plants. This indicated that NaCl markedly improved the pollen viability and preservation time via the increased expression of pollen development-related genes, and this benefits the population establishment of halophytes such as S. salsa in saline regions.

Optimizing outcomes in pancreas transplantation: Impact of organ preservation time.

Recent changes to pancreas graft allocation policy have increased the number of organs available for regional and distant sharing, which results in a corresponding increase in preservation time. We sought to systematically assess the impact of cold ischemia time (CIT) on outcomes post-transplant. A retrospective review of 1253 pancreas transplants performed at a single transplant center was performed to correlate CIT to transplant outcomes. The rate of technical failure (TF) increased with 20+ hours of CIT, with a 2.7-fold to 6.2-fold increased rate of TF for pancreas after kidney (PAK), simultaneous pancreas and kidney (SPK), and pancreas transplants overall. Long-term graft survival was best with <12 hours of CIT; graft failure increased 1.2-fold to 1.4-fold with 12-24 hours of CIT and 2.2-fold with 24+ hours. CIT had less influence on the pancreas transplant alone category than either SPK or PAK and had markedly more influence on grafts from older (age >25 years) and overweight (body mass index >25) donors. In the final analysis, grafts with <12 hours of CIT performed the best overall, and strategies that reduce CIT (such as early allocation, pre-recovery cross-matching, and chartered flights for organs) should be considered whenever possible.

Standard donor lung procurement with normothermic ex vivo lung perfusion: A prospective randomized clinical trial.

BACKGROUND: Ex vivo lung perfusion (EVLP) was primarily developed for evaluation of impaired donor lungs. The good clinical results raise the question for its possible impact on lungs meeting standard criteria. Before application of EVLP on such lungs enters routine clinical practice, it must be demonstrated whether EVLP would affect or improve outcome when used in standard donor lungs. We performed a prospective randomized trial to investigate the role of EVLP in standard lung transplantation (Tx). METHODS: This prospective randomized clinical trial compared patients who underwent Tx with ex vivo evaluated donor lungs with an equivalent patient population without previous EVLP. RESULTS: From October 2013 to May 2015, 193 lung Tx were performed at the Medical University of Vienna. During this period, 80 recipient/donor pairs that met the inclusion criteria were included in this trial, 41 pairs in the control group, and 39 in the EVLP group. In the EVLP group, 4 lungs (10.2%) ultimately did not qualify for Tx and were rejected for lung Tx owing to technical reasons (n = 2) and quality criteria (n = 2). Donor and recipient characteristics were comparable in both groups. Total cold ischemic time in the EVLP group was significantly longer for both implanted lungs (first side, 372 minutes vs 291 minutes, p < 0.001; second side, 437 minutes vs 370 minutes, p = 0.001); median duration of surgery showed no differences (277 minutes vs 275 minutes). Median oxygen partial pressure/fraction of inspired oxygen ratio at 24 hours after Tx was 516 (range, 280-557) in the EVLP group and 491 (range, 352-575) in the control group (p = 0.63). Incidence of primary graft dysfunction >1 was lower in the EVLP group at all time points compared with the control group (24 hours, 5.7% vs 19.5%, p = 0.10), and need for post-operative prolonged extracorporeal membrane oxygenation was lower in the EVLP group (5.7% vs 12.2%, p = 0.44). Short-term clinical outcomes did not differ between recipients in the 2 groups. Patients remained intubated (1.6 days vs 1.6 days, p = 0.67), in the intensive care unit (6 days vs 6 days, p = 0.76), and in the hospital (23 days vs 19 days, p = 0.42) for a comparable period of time. The 30-day survival was 97.1% vs 100% (p = 0.46). CONCLUSIONS: This study provides evidence that EVLP can safely be used in standard donor lungs. Functional results and perioperative outcome are comparable to those achieved with standard donor lung preservation techniques. As an evaluation tool, EVLP allows clinicians to identify and to possibly exclude lungs with functional impairment. Finally, EVLP can safely extend total preservation time.

Influence of different preservation conditions and times on the measurement of blood biochemical indicators in Beagle dogs / 中国比较医学杂志

Objective Beagle dogs are commonly used animal for drug safety evaluation .As the necessary parameters , blood biochemical indicators are detected in acute or chronic toxicity tests .This study aims at assessing the influence of different preservation conditions and different preservation time on blood biochemical indicators to ensure the reliability of test results of long-term toxicity assessment .Methods Six Beagle dogs (3 males and 3 females) were used in this study .After collection and preparation of serum samples , biochemical indicators were detected after preservation in refrigerator at 2-8℃for 1, 2, 5, 8, and 12 hours;after preservation in ice transportation boxes at 2-10℃for 2, 5, and 8 hours;and after preservation in refrigerator at -20℃ for 1, 3, and 5 days.The biochemical indicators included alanine aminotransferase ( ALT ) , aspartate aminotransferase ( AST ) and alkaline phosphatase ( ALP ) , total protein ( TP ) , albumin (propagated), urea, creatinine (CREA), glucose (GLU), total cholesterol (TCHO), total bilirubin (TBIL), creatine kinase ( CK ) , gamma pancreatic acyl transferase ( GGT ) , calcium ( CA ) , lactate dehydrogenase ( LDH ) , phosphorus ( P) , high-density lipoprotein cholesterol ( HDL-C) , low density lipoprotein cholesterol ( LDL-C) , triglyceride ( TG) , sodium ( Na+) , potassium ( K+) and chloride ( Cl -) .Results Compared with the results of samples preserved for 1 hour, the LDL-C result of that preserved in refrigerator at -20℃for 5 days was significantly increased (P0.05 ) , and the coefficient of variation of LDH was 41%.Conclusions According to the test results of blood biochemical indicators in the Beagle dogs detected after different preservation conditions and different preservation time in this study , detection test should be done within 1 hour, if not, detection should be done within 12 hours for the samples preserved at 2~8℃, or within 3 days for the sample preserved at -20℃.For transportation of serum samples , the serum samples should be placed in the ice box at 2~10℃, and detection test should be done within 8 hours .

Effects of preservation time on proliferative potential of human limbal stem/progenitor cells.

AIM: To determine the proliferative potential and the maintenance of stem cell activity in stored human limbal tissues, and correlate this with the preservation time, cell viability and the expression of stem cell markers. METHODS: Thirty limbal rims were split into 4 parts and stored in corneal preservation medium at 4°C for 0, 1, 4, or 7 days. The limbal stem cell and mitotic markers P63, CK19, proliferating cell nuclear antigen (PCNA), and Ki67 were determined by immunohistochemical staining. The proliferative potential of limbal epithelial cells was assessed by cell viability, the ability of generating stratified epithelium, and colony forming assay. RESULTS: The stored tissues maintained limbal stratified structure to 7 days and exhibited comparable expression level of stem cell and mitotic markers. The proportion of viable cells decreased with the prolonged preservation time, while colony forming efficiency decreased from the 1(st) day and disappeared at the 4(th) day. When inoculated on amniotic membrane, the cells preserved for 1 day formed a stratified epithelium, while the cells from 4 days' preservation formed a discontinuous layer. CONCLUSION: The colony forming efficiency of limbal epithelial stem/progenitor cells decreased rapidly with the increasing preservation time, while the expression level of markers and capacity of forming epithelial monolayer on amniotic membrane decreased gradually. The limbal epithelial stem cells lost their function earlier than the lost expression level of stem cell markers. This may help us to better choose the appropriate preservation grafts for future limbal stem cell transplantation.

Influence of long cold ischemia preservation time on ultrastructural morphology of donor heart / 复旦学报（医学版）

Objective To investigate the impacts of long cold ischemic preservation time on the ultrastructural changes of donor heart and to provide the data for expanding the heart donor pool. Methods Heart was obtained from brain dead donor and preserved in the the University of Wisconsin (UW) solution at 4℃. Cardiac tissues were harvested at different time points of cold ischemic preservation (6, 8, 10, 12, 14 h) and observed under electron miscroscope. Results Donor heart did not have significant pathologied and ultrastructural changes when cold ischemic preservation time was 6 h. After that, time related impairment of myocardia and endothelium of coronary artery was seen.When ischemic time was longer than 12 h, focal myocardial necrosis and complete loss of the endothelium were detected. Conclusions Myocardial ultrastructure is an important index to evaluate the donor heart quality. Heart, which underwent 10 h of cold ischemia preservation time, causes no significant irreversible and pathological ultrastructural changes, and could be used for heart transplantation. When ischemia time was over 10 h, the donor heart presented with irreversible change and was nolonger unsuitable for transplantation.