Amputated Digit Replantations: Critical Digit Ischemia Timing, Temperature, and Other Predictors of Survival.

INTRODUCTION: A common consideration for replantation success is the ischemia time following injury and the preservation temperature. A classic principle within the hand surgery community describes 12 hours of warm ischemia and 24 hours of cold ischemia as the upper limits for digit replantation; however, these limits are largely anecdotal and based on older studies. We aimed to compare survival data from the large body of literature to aid surgeons and all those involved in the replantation process in hopes of optimizing success rates. METHODS: The PubMed database was queried on April 4th, 2023, for articles that included data on digit replantation survival in terms of temperature of preservation and ischemia time. All primary outcomes were analyzed with the Mantel-Haenszel method within a random effects model. Secondary outcomes were pooled and analyzed using the chi-square statistic. Statistical analysis and forest plot generation were completed with RevMan 5.4 software with odds ratios calculated within a 95% confidence interval. RESULTS: Our meta-analysis identified that digits preserved in cold ischemia for over 12 hours had significantly higher odds of replantation success than the amputated digits replanted with 0-12 hours of warm ischemia time ( P ≤ 0.05). The odds of survival in the early (0-6 hours) replantation group were around 40% greater than the later (6-12 hours) replantation group ( P ≤ 0.05). Secondary outcomes that were associated with higher survival rates included a clean-cut amputation, increased venous and arterial anastomosis, a repair that did not require a vein graft, and replants performed in nonsmokers ( P ≤ 0.05). DISCUSSION: Overall, these findings suggest that when predicting digit replantation success, time is of the essence when the digit has yet to be preserved in a cold environment. This benefit, however, is almost completely diminished when the amputated digit is appropriately maintained in a cold environment soon after injury. In conclusion, our results suggest that there is potential for broadening the ischemia time limits for digit replant survival outlined in the literature, particularly for digits that have been stored correctly in cold ischemia.

The role of cold ischemia time and hypothermic perfusion in predicting early hepatocellular carcinoma recurrences after liver transplantation.

AIM: The aim of the study was to identify predictors of early tumor recurrence in patients with hepatocellular carcinoma (HCC) after liver transplantation (LT). METHODS: Retrospective cohort study in 237 consecutive liver recipients with HCC between 2016 and 2021. Multivariate logistic analysis was performed to identify predictors of early HCC recurrences. The impact of hypothermic-oxygenated perfusion (HOPE) on outcome was analyzed after propensity score weighting. RESULTS: Early recurrences were observed in 15 cases. Microvascular invasion (OR 3.737, 95% CI 1.246-11.206, p = 0.019) and cold ischemia time (OR 1.155, 95% CI 1.001-1.333, p = 0.049) were independently associated with a lower risk of HCC recurrences. After balancing for relevant variables, patients in the HOPE group had lower rates of tumor recurrence (weighted OR 0.126, 95% CI 0.016-0.989, p = 0.049) and higher recurrence free survival (weighted HR 0.132, 95% CI 0.017-0.999, p = 0.050). CONCLUSION: Reducing cold ischemia time and graft perfusion with HOPE can lead to lower rates of early HCC recurrences and higher recurrence-free survival.

Impact of Cold Ischemia on the Stability of 1H-MRS-Detected Metabolic Profiles of Ovarian Cancer Specimens.

Proton magnetic resonance spectroscopy (1H-MRS) of surgically collected tumor specimens may contribute to investigating cancer metabolism and the significance of the "total choline" (tCho) peak (3.2 ppm) as malignancy and therapy response biomarker. To ensure preservation of intrinsic metabolomic information, standardized handling procedures are needed. The effects of time to freeze (cold ischemia) were evaluated in (a) surgical epithelial ovarian cancer (EOC) specimens using high-resolution (HR) 1H-MRS (9.4 T) of aqueous extracts and (b) preclinical EOC samples (xenografts in SCID mice) investigated by in vivo MRI-guided 1H-MRS (4.7 T) and by HR-1H-MRS (9.4 T) of tumor extracts or intact fragments (using magic-angle-spinning (MAS) technology). No significant changes were found in the levels of 27 of 29 MRS-detected metabolites (including the tCho profile) in clinical specimens up to 2 h cold ischemia, besides an increase in lysine and a decrease in glutathione. EOC xenografts showed a 2-fold increase in free choline within 2 h cold ischemia, without further significant changes for any MRS-detected metabolite (including phosphocholine and tCho) up to 6 h. At shorter times (≤1 h), HR-MAS analyses showed unaltered tCho components, along with significant changes in lactate, glutamate, and glutamine. Our results support the view that a time to freeze of 1 h represents a safe threshold to ensure the maintenance of a reliable tCho profile in EOC specimens.

Impact of Decalcification, Cold Ischemia, and Deglycosylation on Performance of Programmed Cell Death Ligand-1 Antibodies With Different Binding Epitopes: Comparison of 7 Clones.

Programmed cell death ligand-1 (PD-L1) expression levels in patients' tumors have demonstrated clinical utility across many cancer types and are used to determine treatment eligibility. Several independently developed PD-L1 immunohistochemical (IHC) predictive assays are commercially available and have demonstrated different levels of staining between assays, generating interest in understanding the similarities and differences between assays. Previously, we identified epitopes in the internal and external domains of PD-L1, bound by antibodies in routine clinical use (SP263, SP142, 22C3, and 28-8). Variance in performance of assays utilizing these antibodies, observed following exposure to preanalytical factors such as decalcification, cold ischemia, and duration of fixation, encouraged additional investigation of antibody-binding sites, to understand whether binding site structures/conformations contribute to differential PD-L1 IHC assay staining. We proceeded to further investigate the epitopes on PD-L1 bound by these antibodies, alongside the major clones utilized in laboratory-developed tests (E1L3N, QR1, and 73-10). Characterization of QR1 and 73-10 clones demonstrated that both bind the PD-L1 C-terminal internal domain, similar to SP263/SP142. Our results also demonstrate that under suboptimal decalcification or fixation conditions, the performance of internal domain antibodies is less detrimentally affected than that of external domain antibodies 22C3/28-8. Furthermore, we show that the binding sites of external domain antibodies are susceptible to deglycosylation and conformational structural changes, which directly result in IHC staining reduction or loss. The binding sites of internal domain antibodies were unaffected by deglycosylation or conformational structural change. This study demonstrates that the location and conformation of binding sites, recognized by antibodies employed in PD-L1 diagnostic assays, differ significantly and exhibit differing degrees of robustness. These findings should reinforce the need for vigilance when performing clinical testing with different PD-L1 IHC assays, particularly in the control of cold ischemia and the selection of fixation and decalcification conditions.

Reassessing Geographic, Logistical, and Cold Ischemia Cutoffs in Liver Transplantation.

INTRODUCTION: Liver acceptance patterns vary significantly between transplant centers. Data pertaining to outcomes of livers declined by local and regional centers and allocated nationally remains limited. PROJECT AIM: The objective was to compare post-liver transplant outcomes between liver allografts transplanted as a result of national and local-regional allocation. DESIGN: This was a retrospective evaluation of 109 nationally allocated liver allografts used for transplant by a single center. Outcomes of nationally allocated grafts were compared to standard allocation grafts (N = 505) during the same period. RESULTS: Recipients of nationally allocated grafts had lower model for end stage liver disease scores (17 vs 22, P = .001). Nationally allocated grafts were more likely to be post-cross clamp offers (29.4% vs 13.4%, P = .001) and have longer cold ischemia times (median hours 7.8 vs 5.5, P = .001). Early allograft dysfunction was common (54.1% vs 52.5%, P = .75) and did not impact hospital length of stay (median 5 vs 6 days, P = .89). There were no differences in biliary complications (P = .11). There were no differences in patient (P = .88) or graft survival (P = .35). In a multivariate model, after accounting for differences in cold ischemia time and posttransplant biliary complications, nationally allocated grafts were not associated with increased risk for graft loss (HR 0.9, 95% CI 0.4-1.8). Abnormal liver biopsy findings (33.0%) followed by donor donation after circulatory death status (22.9%) were the most common reasons for decline by local-regional centers. CONCLUSION: Despite longer cold ischemia times, patient and graft survival outcomes remain excellent and comparable to those seen from standard allocation grafts.

Protective Effect of Calpain Inhibition During Cold Ischemia on Ischemia-reperfusion Injury After Lung Transplantation.

BACKGROUND: Necroptosis, one of the types of regulated necrosis, causes ischemia-reperfusion (IR) lung injury. N-acetyl-leucyl-leucyl-norleucinal (ALLN), a calpain inhibitor, is known to attenuate necroptosis and apoptosis, and the purpose of this study was to evaluate the protective effect of ALLN during cold ischemia against IR injury in a rat lung transplant model. METHODS: Male Lewis rats (250-350 g) were divided into 3 groups: sham group (n = 4), nontransplantation; control group (n = 8), transplantation with IR lung injury; and ALLN group (n = 8), transplantation with IR lung injury/ALLN. Rats in the sham group underwent a simple thoracotomy, and the remaining 2 groups of rats underwent an orthotopic left lung transplant. Cold ischemic time was 15 h. After 2 h of reperfusion, physiological function, inflammatory cytokine expression, pathway activation, and the degrees of necroptosis and apoptosis were evaluated. RESULTS: Lung gas exchange (PaO 2 /FiO 2 ) was significantly better, and pulmonary edema was significantly improved in the ALLN group compared with the control group ( P = 0.0009, P = 0.0014). Plasma expression of interleukin-1ß was significantly lower in the ALLN group than in the control group ( P = 0.0313). The proportion of necroptotic and apoptotic cells was significantly lower in the ALLN group than in the control group ( P = 0.0009), whereas the proportion of apoptotic cells remained unchanged ( P = 0.372); therefore, the calpain inhibitor was thought to suppress necroptosis. CONCLUSIONS: The administration of ALLN during cold ischemia appears to improve IR lung injury in a lung transplant animal model via the inhibition of necroptosis.

Danger signals released during cold ischemia storage activate NLRP3 inflammasome in myeloid cells and influence early allograft function in liver transplantation.

BACKGROUND: Innate immunity plays a fundamental role in solid organ transplantation. Myeloid cells can sense danger signals or DAMPs released after tissue or cell damage, such as during ischemia processes. This study aimed to identify DAMPs released during cold ischemia storage of human liver and analyze their ability to activate the inflammasome in myeloid cells and the possible implications in terms of short-term outcomes of liver transplantation. METHODS: 79 samples of organ preservation solution (OPS) from 79 deceased donors were collected after cold static storage. We used different analytical methods to measure DAMPs in these end-ischemic OPS (eiOPS) samples. We also used eiOPS in the human macrophage THP-1 cell line and primary monocyte cultures to study inflammasome activation. FINDINGS: Different DAMPs were identified in eiOPS, several of which induced both priming and activation of the NLRP3 inflammasome in human myeloid cells. Cold ischemia time and donation after circulatory death negatively influenced the DAMP signature. Moreover, the presence of oligomeric inflammasomes and interleukin-18 in eiOPS correlated with early allograft dysfunction in liver transplant patients. INTERPRETATION: DAMPs released during cold ischemia storage prime and activate the NLRP3 inflammasome in liver macrophages after transplantation, inducing a pro-inflammatory environment that will complicate the outcome of the graft. The use of pharmacological blockers targeting DAMPs or the NLRP3 inflammasome in liver ischemia during static cold storage or through extracorporeal organ support could be a suitable strategy to increase the success of liver transplantation. FUNDING: Fundación Mutua Madrileña and Instituto de Salud Carlos III, Madrid, Spain.

Cellular Cytosolic Energy Replenishment Increases Vascularized Composite Tissue Tolerance to Extended Cold Ischemia Time.

BACKGROUND: Vascularized composite allotransplantation (VCA) is a restorative surgical procedure to treat whole or partially disfiguring craniofacial or limb injuries. The routine clinical use of this VCA surgery is limited using compromised allografts from deceased donors and by the failure of the current hypothermic preservation protocols to extend the allograft's cold ischemia time beyond 4 h. We hypothesized that the active replenishment of the cellular cytosolic adenosine-5`-triphosphate (ATP) stores by means of energy delivery vehicles (ATPv) encapsulating high-energy ATP is a better strategy to improve allograft's tolerance to extended cold ischemia times. MATERIALS AND METHODS: We utilized established rat model of isolated bilateral in-situ non-cycled perfusions of both hind limbs. Ipsilateral and contralateral limbs in the anesthetized animal were randomized for simultaneous perfusions with either the University of Wisconsin (UW) solution, with/without O2 supplementation (control), or with the UW solution supplemented with the ATPv, with/without O2 supplementation (experimental). Following perfusion, the hind limbs were surgically removed and stored at 4°C for 12, 16, or 24 hours as extended cold ischemia times. At the end of each respective storage time, samples of skin, and soleus, extensor digitalis longus, and tibialis anterior muscles were recovered for assessment using tissue histology and tissue lysate studies. RESULTS: Control muscle sections showed remarkable microvascular and muscle damage associated with loss of myocyte transverse striation and marked decrease in myocyte nucleus density. A total of 1,496 nuclei were counted in 179 sections of UW-perfused control muscles in contrast to 1,783 counted in 130 sections of paired experimental muscles perfused with the ATPv-enhanced perfusate. This yielded 8 and 13 nuclei/field for the control and experimental muscles, respectively (P < .004). Oxygenation of the perfusion solutions before use did not improve the nucleus density of either the control or experimental muscles (n = 7 animals, P > .05). Total protein isolated from the muscle lysates was similar in magnitude regardless of muscle type, perfusion protocol, or duration of cold ischemia time. Prolonged static cold preservation of the hind limbs completely degraded the composite tissue's Ribonucleic acid (RNA). This supplementary result confirms the notion that that reverse transcription-Polymerase Chain Reaction, enzyme-linked immunosorbent assay, or the respiratory complex II enzyme activity techniques should not be used as indices of graft quality after prolonged static cold storage. CONCLUSIONS: In conclusion, this study demonstrates that active cellular cytosolic ATP replenishment increases hind limb composite tissue tolerance to extended cold ischemia times. Quality indicators and clinically relevant biomarkers that define composite tissue viability and function during static cold storage are warranted.

Real-life data from standardized preanalytical coding (SPREC) in tissue biobanking and its dual use for sample characterization and process optimization.

The standardized preanalytical code (SPREC) aggregates warm ischemia (WIT), cold ischemia (CIT), and fixation times (FIT) in a precise format. Despite its growing importance underpinned by the European in vitro diagnostics regulation or broad preanalytical programs by the National Institutes of Health, little is known about its empirical occurrence in biobanked surgical specimen. In several steps, the Tissue Bank Bern achieved a fully informative SPREC code with insights from 10,555 CIT, 4,740 WIT, and 3,121 FIT values. During process optimization according to LEAN six sigma principles, we identified a dual role of the SPREC code as a sample characteristic and a traceable process parameter. With this preanalytical study, we outlined real-life data in a variety of organs with specific differences in WIT, CIT, and FIT values. Furthermore, our FIT data indicate the potential to adapt the SPREC fixation toward concrete paraffin-embedding time points and to extend its categories beyond 72 h due to weekend delays. Additionally, we identified dependencies of preanalytical variables from workload, daytime, and clinics that were actionable with LEAN process management. Thus, streamlined biobanking workflows during the day were significantly resilient to workload peaks, diminishing the turnaround times of native tissue processing (i.e. CIT) from 74.6 to 46.1 min under heavily stressed conditions. In conclusion, there are surgery-specific preanalytics that are surgico-pathologically limited even under process optimization, which might affect biomarker transfer from one entity to another. Beyond sample characteristics, SPREC coding is highly beneficial for tissue banks and Institutes of Pathology to track WIT, CIT, and FIT for process optimization and monitoring measurements.

Defining Surgical Difficulty of Liver Transplantation.

OBJECTIVE: To define technically Diff-LT. SUMMARY OF BACKGROUND DATA: Currently, there is no acknowledged definition of Diff-LT. METHODS: This retrospective study included all first consecutive liver-only transplantations performed in 2 centers from 2011 to 2015. Diff-LT was defined as the combination of the number of blood units transfused, cold ischemia time, and duration of operation, all at or above the median value of the entire population. The correlation of Diff-LT with short- (including the comprehensive complication index) and long-term outcomes was assessed. Outcomes were also compared to the 90-day benchmark cutoffs of LT. Predictors of Diff-LT were identified by multivariable analysis, first using only recipient data and then using all recipient, donor, graft, and surgical data. RESULTS: The study population included 467 patients. The incidence of Diff- LT was 18.8%. Diff-LT was associated with short-term outcomes, including the comprehensive complication index and mortality, but not with patient or graft long-term survival. Previous abdominal surgery, intensive care unitbound at the time of LT, split graft use, nonstandard arterial reconstruction, and porto-systemic shunt ligation were independent predictors of Diff-LT. The proportion of variables below the corresponding LT 90-day benchmark cutoffs was 8/13 (61.5%) for non-Diff-LT, and 4/13 (30.8%) for Diff-LT. CONCLUSIONS: Diff-LT, as defined, occurred frequently. Adjusting modifiable variables might decrease the risk of Diff-LT and improve the postoperative course. This definition of Diff-LT might be useful for patient information, comparison between centers and surgeons, and as a metric in future trials.

Efetividade da máquina de perfusão hipotérmica versus armazenamento estático para preservação do rim de doador falecido: revisão rápida / Effectiveness of hypothermic machine perfusion versus cold static storage for deceased donor kidney preservation: rapid review

Tecnologia: máquina de perfusão hipotérmica. Indicação: Transplante renal de doador falecido. Pergunta: Qual a efetividade da máquina de perfusão hipotérmica (HMP) para a preservação do rim de doador falecido, quando comparada ao armazenamento estático a frio (SCS)? Objetivo. Avaliar a efetividade da máquina de perfusão hipotérmica na preservação do rim de doador falecido, em comparação com o armazenamento estático a frio. Métodos: Revisão de revisões sistemáticas (overview) do tipo revisão rápida. Foi realizado um levantamento bibliográfico nas bases de dados: PubMed, Embase, BVS, Epistemonikos, Cochrane Library e em bases de registro de protocolos de revisões sistemáticas e ensaios clínicos, utilizando descritores e estratégias de busca predefinidas. A avaliação da qualidade metodológica dos estudos incluídos foi feita através da ferramenta AMSTAR-2 (Assessing the Methodological Quality of Systematic Reviews Version 2). Resultados: Duas revisões sistemáticas atenderam aos critérios de elegibilidade e foram incluídas na análise. Uma delas apresentou alto nível de qualidade metodológica. Conclusão: O uso da HMP para a preservação de rins de doadores falecidos foi associado a melhores desfechos clínicos relacionados à função retardada e à sobrevida do enxerto e foi considerado custo-efetivo, quando comparado ao SCS. Faz-se necessária a geração de evidências mais robustas acerca dos custos e benefícios do uso desta tecnologia no âmbito do SUS

Technology: hypothermic machine perfusion. Indication: Deceased donor kidney transplantation. Question: How effective is hypothermic machine perfusion (HMP) for preserving deceased donor kidneys compared to static cold storage (SCS)? Objective: To evaluate the effectiveness of the hypothermic machine perfusion in preserving the deceased donor kidney, compared to static cold storage. Methods: Rapid review of systematic reviews (overview). A bibliographic survey was carried out in the databases: PubMed, Embase, VHL, Epistemonikos, Cochrane Library and in databases of systematic review protocols and clinical trials, using predefined descriptors and search strategies. The assessment of the methodological quality of the included studies was performed using the AMSTAR-2 tool (Assessing the Methodological Quality of Systematic Reviews Version 2). Results: Two systematic reviews met the eligibility criteria and were included in the analysis. One of them performed a high level of methodological quality. Conclusion: The use of HMP for the preservation of deceased donor kidneys was associated with better clinical outcomes related to delayed graft function and graft survival and was considered cost-effective. It is necessary to generate more evidence about the costs and benefits of using this technology within the Brazilian Unified System of Healthcare (SUS)

Mitochondrial respiration during normothermic liver machine perfusion predicts clinical outcome.

BACKGROUND: Reliable biomarkers for organ quality assessment during normothermic machine perfusion (NMP) are desired. ATP (adenosine triphosphate) production by oxidative phosphorylation plays a crucial role in the bioenergetic homeostasis of the liver. Thus, detailed analysis of the aerobic mitochondrial performance may serve as predictive tool towards the outcome after liver transplantation. METHODS: In a prospective clinical trial, 50 livers were subjected to NMP (OrganOx Metra) for up to 24.ßh. Biopsy and perfusate samples were collected at the end of cold storage, at 1.ßh, 6.ßh, end of NMP, and 1.ßh after reperfusion. Mitochondrial function and integrity were characterized by high-resolution respirometry (HRR), AMP, ADP, ATP and glutamate dehydrogenase analysis and correlated with the clinical outcome (L-GrAFT score). Real-time confocal microscopy was performed to assess tissue viability. Structural damage was investigated by histology, immunohistochemistry and transmission electron microscopy. FINDINGS: A considerable variability in tissue viability and mitochondrial respiration between individual livers at the end of cold storage was observed. During NMP, mitochondrial respiration with succinate and tissue viability remained stable. In the multivariate analysis of the 35 transplanted livers (15 were discarded), area under the curve (AUC) of LEAK respiration, cytochrome c control efficiency (mitochondrial outer membrane damage), and efficacy of the mitochondrial ATP production during the first 6.ßh of NMP correlated with L-GrAFT. INTERPRETATIONS: Bioenergetic competence during NMP plays a pivotal role in addition to tissue injury markers. The AUC for markers of outer mitochondrial membrane damage, ATP synthesis efficiency and dissipative respiration (LEAK) predict the clinical outcome upon liver transplantation. FUNDING: This study was funded by a Grant from the In Memoriam Dr. Gabriel Salzner Stiftung awarded to SS and the Tiroler Wissenschaftsfond granted to TH.

Effects of prolonged cold ischemia on the DCD kidney function and Inflammasome expression in rat kidney transplants.

BACKGROUND: Acute kidney injury (AKI) is the main reason for the bad outcome of the donation of circulatory death (DCD) kidney after transplantation. Prolonged cold storage (CS) is a risk factor for the occurrence of the delayed graft function in DCD kidney. The protein NLR-domain containing receptor 3 (NLRP3) plays a crucial role in renal ischemia reperfusion injury by triggering inflammasome formation. Herein, we investigated whether the NLRP3 signal participate in the CS-induced damage of DCD kidney in rat kidney transplantation models. MATERIALS AND METHODS: DCD kidney and living donor (LD) kidney of SD rats were preserved in UW solution at 4 °C for 2 h or 18 h, and then transplanted into syngeneic recipient. Thus, the animals were randomly divided into 4 groups: 2-h LD group, 2-h DCD group, 18-h LD group and 18-h DCD group. The renal function and pathological changes were determined. The expressions of NLRP3 and inflammatory factor IL-1ß were assessed. The concentration of ferrous iron (Fe2+) was analyzed both in kidneys and in the preservation solution. The renal morphological changes were examined by hematoxylin eosin staining. RESULTS: Our results showed that the levels of Cr and BUN were higher in 18-h LD group as compared to the 2-h LD group, which were remarkably increased in 18-h DCD group. The expression levels of NLRP3 and IL-1ß were increased by 18-h CS compared to 2-h CS in both LD kidney and DCD kidney. In addition, the Fe2+ concentration has significantly increased in 18-h LD group than that in 2-h LD group, and the elevation of Fe2+ was more remarkable in DCD kidneys. CONCLUSION: In conclusion, our study demonstrated that prolonged hypothermic storage of DCD kidney deteriorated the graft function via the increased Fe2+ concentration, which was associated with the upregulation of NLRP3 expression.

Mesenchymal stem cell secretions improve donor heart function following ex vivo cold storage.

OBJECTIVES: Heart transplantation is the gold standard of treatments for end-stage heart failure, but its use is limited by extreme shortage of donor organs. The time "window" between procurement and transplantation sets the stage for myocardial ischemia/reperfusion injury, which constrains the maximal storage time and lowers use of donor organs. Given mesenchymal stem cell (MSC)-derived paracrine protection, we aimed to evaluate the efficacy of MSC-conditioned medium (CM) and extracellular vesicles (EVs) when added to ex vivo preservation solution on ameliorating ischemia/reperfusion-induced myocardial damage in donor hearts. METHODS: Mouse donor hearts were stored at 0°C-4°C of <1-hour cold ischemia (<1hr-I), 6hr-I + vehicle, 6hr-I + MSC-CM, 6hr-I + MSC-EVs, and 6hr-I + MSC-CM from MSCs treated with exosome release inhibitor. The hearts were then heterotopically implanted into recipient mice. At 24 hours postsurgery, myocardial function was evaluated. Heart tissue was collected for analysis of histology, apoptotic cell death, microRNA (miR)-199a-3p expression, and myocardial cytokine production. RESULTS: Six-hour cold ischemia significantly impaired myocardial function, increased cell death, and reduced miR-199a-3p in implanted hearts versus <1hr-I. MSC-CM or MSC-EVs in preservation solution reversed the detrimental effects of prolong cold ischemia on donor hearts. Exosome-depleted MSC-CM partially abolished MSC secretome-mediated cardioprotection in implanted hearts. MiR-199a-3p was highly enriched in MSC-EVs. MSC-CM and MSC-EVs increased cold ischemia-downregulated miR-199a-3p in donor hearts, whereas exosome-depletion neutralized this effect. CONCLUSIONS: MSC-CM and MSC-EVs confer improved myocardial preservation in donor hearts during prolonged cold static storage and MSC-EVs can be used for intercellular transport of miRNAs in heart transplantation.

Controlled Oxygenated Rewarming Compensates for Cold Storage-induced Dysfunction in Kidney Grafts.

BACKGROUND: Normothermic machine perfusion (NMP) provides a promising strategy for preservation and conditioning of marginal organ grafts. However, at present, high logistic effort limits normothermic renal perfusion to a short, postponed machine perfusion at site of the recipient transplant center. Thus, organ preservation during transportation still takes place under hypothermic conditions, leading to significantly reduced efficacy of NMP. Recently, it was shown that gentle and controlled warming up of cold stored kidneys compensates for hypothermic induced damage in comparison to end ischemic NMP. This study aims to compare controlled oxygenated rewarming (COR) with continuous upfront normothermic perfusion in a porcine model of transplantation. METHODS: Following exposure to 30 min of warm ischemia, kidneys (n = 6/group) were removed and either cold stored for 8 h (cold storage [CS]), cold stored for 6 h with subsequent controlled rewarming up to 35 °C for 2 h (COR), or directly subjected to 8 h of continuous NMP. Kidney function was evaluated using a preclinical autotransplant model with follow-up for 7 d. RESULTS: NMP and COR both improved renal function in comparison to CS and displayed similar serum creatinine and urea levels during follow-up. COR resulted in less tenascin C expression in the tissue compared with CS, indicating reduced proinflammatory upregulation in the graft by gentle rewarming. CONCLUSIONS: COR seems to be a potential alternative in clinical application of NMP, thereby providing logistic ease and usability.

BSHI/BTS guidance on crossmatching before deceased donor kidney transplantation.

All UK H&I laboratories and transplant units operate under a single national kidney offering policy, but there have been variations in approach regarding when to undertake the pre-transplant crossmatch test. In order to minimize cold ischaemia times for deceased donor kidney transplantation we sought to find ways to be able to report a crossmatch result as early as possible in the donation process. A panel of experts in transplant surgery, nephrology, specialist nursing in organ donation and H&I (all relevant UK laboratories represented) assessed evidence and opinion concerning five factors that relate to the effectiveness of the crossmatch process, as follows: when the result should be ready for reporting; what level of donor HLA typing is needed; crossmatch sample type and availability; fairness and equity; risks and patient safety. Guidelines aimed at improving practice based on these issues are presented, and we expect that following these will allow H&I laboratories to contribute to reducing CIT in deceased donor kidney transplantation.

Is night-time surgical procedure for renal graft at higher risk than during the day? A single center study cohort of 179 patients.

INTRODUCTION: Various surgical centers tend to postpone a kidney transplantation (KT) to the following morning than to operate at night-time. The objective of our study was to assess whether there was any difference between daytime and night-time renal transplantation in our institution. METHOD: This study is a retrospective monocentric study including all the KTs that were performed between 2012 and 2013 by transplant expert surgeons in our institution. Clavien-Dindo (CD) complications were classified according to 7 variables going from 1 to 5. Time before postgraft diuresis and delayed graft function (DGF) were also analyzed. Two groups of patients were formed according to threshold value of incision time (6.30 p.m.). Data comparison were performed using the Kruskal-Wallis nonparametric test. RESULTS: A total of 179 patients were included. Median follow-up was 24 months. Cold ischemia time was longer in the night-time transplantation (1082 vs. 807 min, p < .001), but rewarming time was shorter (47.24 vs. 52.15 min, p = .628). No statistically significant differences were observed between the two groups using the Kruskal-Wallis method for CD complications (Qobs: 0.076; p = .735). CD complications proportion was similar, with a majority of grade II complications (72.7% daytime group vs. 75.4% night-time group (p = .735). DGF (19 patients for daytime group vs. 13 patients for night-time group, p = .359) and time before postgraft diuresis (4.65 days daytime group vs. 5.27 days night-time group, p = .422) were similar between both groups. Multivariate analysis did not show significant predictors of CD complications Grade 3 and more. CONCLUSION: Night-time renal transplantation did not induce more postoperative CD complications than diurnal procedures in our cohort, challenging the false preconceptions that allow surgical teams to delay this surgery.

Sodium thiosulfate-supplemented UW solution protects renal grafts against prolonged cold ischemia-reperfusion injury in a murine model of syngeneic kidney transplantation.

INTRODUCTION: Cold ischemia-reperfusion injury (IRI) is an inevitable event that increases post-transplant complications. We have previously demonstrated that supplementation of University of Wisconsin (UW) solution with non-FDA-approved hydrogen sulfide (H2S) donor molecules minimizes cold IRI and improves renal graft function after transplantation. The present study investigates whether an FDA-approved H2S donor molecule, sodium thiosulfate (STS), will have the same or superior effect in a clinically relevant rat model of syngeneic orthotopic kidney transplantation. METHOD: Thirty Lewis rats underwent bilateral nephrectomy followed by syngeneic orthotopic transplantation of the left kidney after 24-hour preservation in either UW or UW+STS solution at 4 °C. Rats were monitored to post-transplant day 14 and sacrificed to assess renal function (urine output, serum creatinine and blood urea nitrogen). Kidney sections were stained with H&E, TUNEL, CD68, and myeloperoxidase (MPO) to detect acute tubular necrosis (ATN), apoptosis, macrophage infiltration, and neutrophil infiltration. RESULT: UW+STS grafts showed significantly improved graft function immediately after transplantation, with improved recipient survival compared to UW grafts (p < 0.05). Histopathological examination revealed significantly reduced ATN, apoptosis, macrophage and neutrophil infiltration and downregulation of pro-inflammatory and pro-apoptotic genes in UW+STS grafts compared to UW grafts (p < 0.05). CONCLUSION: We show for the first time that preservation of renal grafts in STS-supplemented UW solution protects against prolonged cold IRI by suppressing apoptotic and inflammatory pathways, and thereby improving graft function and prolonging recipient survival. This could represent a novel clinically applicable therapeutic strategy to minimize the detrimental clinical outcome of prolonged cold IRI in kidney transplantation.

Surgical site complications in kidney transplant recipients: incidence, risk factors and outcomes in the modern era.

BACKGROUND: Surgical site complications (SSCs) are an important source of morbidity after kidney transplantation. We assessed the incidence, risk factors, outcomes and economic impact of SSCs in a large, diverse population of kidney transplant recipients. METHODS: We conducted a single-centre, observational cohort study of adult (age ≥ 18 yr) patients who underwent kidney transplantation between Jan. 1, 2005, and Dec. 31, 2015, with a minimum of 1 year of follow-up. Cases of SSC, including infections and wound dehiscence, were determined from patient records. Inpatient and outpatient hospital costs were determined 6 and 12 months after transplantation. We used the Kaplan-Meier product-limit method to determine the cumulative probability of SSCs and other outcomes. We evaluated risk factors and clinical outcomes using Cox proportional hazard ratios. Linear regression models were used to study the effect of SSCs on graft function. RESULTS: The incidence rate of SSCs within 30 days after transplantation was 4.19 per 100 person-months. The cumulative probability of developing an SSC within 30 days after transplantation was 4.13% (95% confidence interval [CI] 3.23%-5.28%). Increased recipient body mass index (BMI) (hazard ratio [HR] 1.07, 95% CI 1.02-1.11), longer cold ischemic time (HR 1.05, 95% CI 1.01-1.09) and transplantation in 2010-2012 versus 2005-2009 (HR 2.20, 95% CI 1.19-4.04) were risk factors for SSC development. In multivariable stepwise Cox proportional hazard models, SSC was a significant risk factor for death-censored graft failure (HR 3.08, 95% CI 1.60-5.90) and total graft failure (HR 2.09, 95% CI 1.32-3.32). Cumulative median hospital costs were $2238.46 greater for patients with an SSC than for those without. CONCLUSION: Increased BMI, longer cold ischemic time and the 2010-2012 transplantation period predisposed to SSCs. The development of SSCs was associated with a higher risk of graft failure. Strategies to minimize SSCs may improve outcomes after kidney transplantation and reduce costs.