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.

A New Medium (HistoCold) for Surgical Specimens Preserving to Improve the Preanalytic Issues in Histopathological Samples Handling: Morphologic and Antigenic Analysis

Introduction: The onset of precision medicine has led to the integration of traditional morphologic tissues evaluation with biochemical and molecular data for a more appropriate pathological diagnosis. The preanalytic phase and, particularly, timing of cold ischemia are crucial to guarantee high-quality biorepositories of formalin-fixed paraffin-embedded (FFPE) tissues for patients' needs and scientific research. However, delayed fixation using the gold-standard and carcinogenic fixative neutral-buffered formalin (NBF) can be a significant limitation to diagnosis and biopathological characterization. HistoCold (patented; Bio-Optica Milano S.p.A., Milano, Italy) is a nontoxic, stable, and refrigerated preservative solution for tissue handling. This study examined HistoCold's potential role in improving the preanalytic phase of the pathological diagnostic process. Materials and Methods: Breast, lung, or colorectal cancers (20, 25, and 10 cases, respectively) that were to be surgically resected were recruited between 2019 and 2021. Once specimens were surgically removed, three residual samples for each patient were first promptly immersed into HistoCold for 24, 48, and 72 hours and then FFPE. These were compared with routine specimens regarding morphologic features (hematoxylin and eosin) and tissue antigenicity (immunohistochemical stains). Results: Good concordance regarding both the morphologic characteristics of the neoplasms and their proteins expression between the routine and HistoCold handled tissues were found. The tissue handling with the solution never affected the histopathological diagnosis. Conclusions: The use of HistoCold for samples transporting is easy, allows for improving the management of cold ischemia time, and monitoring the fixation times in NBF, resulting in good quality tissue blocks for biobanking. Moreover, it could be a candidate to eliminate formalin from operating theaters. HistoCold looks very promising for the preanalytic phase of human tissues handling in the era of precision medicine, to provide the best service to patients, and to scientific research.

Hypothermic machine perfusion for uterus transplantation

OBJECTIVE

To describe the feasibility of hypothermic machine perfusion (HMP) in uterus transplantation (UT) to potentially improve the preservation of the uterus and enhance graft preservation in the donation after brainstem death (DBD) context. Uterus transplantation is a new surgical approach to treating absolute uterine infertility; it can be performed after living donation or after DBD. In the DBD context, the uterus is typically the last organ removed after other vital organs, with the exception of the Baylor team, which removes the uterus first. This key aspect imposes an unavoidable mild temperature ischemia for >1 hour on the uterus during the removal of the vital abdominal and chest organs. In renal transplantation, the perfusion machine reduces the risk of delayed graft function; thus, we hypothesized that machine perfusion could result in a reduction of uterus graft dysfunction. The uterus graft dysfunction could be expressed by a low embryo implantation rate, pregnancy loss, or vascular pregnancy diseases such as preeclampsia or fetal growth restriction." To date, static cold storage of the uterus is the only standard method for preservation before transplantation. HMP is an emerging method that could potentially improve the preservation of the uterus to enhance graft preservation in the DBD context.

DESIGN

This video article shows all the technical details of using the HMP for uterine transplantation.

SETTING

University.

ANIMALS

Porcine model.

INTERVENTION

Porcine uterus was retrieved from a DBD domestic animal model and flushed with KPS MP (Bridge To Life Ltd in UK) at 4 °C. After vascular preparation on the back table, the uterus was perfused using KPS MP through a cannula in the aorta using the VitaSmart device (Bridge To Life Ltd in UK) for 18 hours. Then, the uterus was transplanted to the porcine recipient.

MAIN OUTCOME MEASURES

The macroscopic appearance of the uterus at the end of HMP and the assessment of the uterus vascularization after transplantation in the recipient compared with the native uterus.

RESULTS

This video shows the cannulation of the iliac vessels, cooling and removal of the uterus on a porcine model, uterus preservation using HMP during 18 hours, and then UT in a new recipient pig with the reperfusion of the transplanted uterus next to the native, intact uterus of the recipient. The macroscopic appearance of the uterus at the end of HMP appeared viable and was perfectly flushed. The assessment of the uterus vascularization after transplantation in the recipient was similar to that of the native uterus. To our knowledge, we describe here for the first time the UT procedure in DBD context on an animal model and the use of HMP for uterus preservation in UT programs; this could increase the number of uterine grafts available for a greater number of female recipients.

CONCLUSION

Hypothermic machine perfusion could allow the duration of cold ischemia to be prolonged without altering the uterine graft. Nevertheless, this assertion has to be validated in a human context.

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.

The Impact of Combined Warm and Cold Ischemia Time on Post-transplant Outcomes

Background

Prolonged warm ischemia time (WIT) and cold ischemia time (CIT) are independently associated with post-transplant graft failure; their combined impact has not been previously studied. We explored the effect of combined WIT/CIT on all-cause graft failure following kidney transplantation.

Methods

The Scientific Registry of Transplant Recipients was used to identify kidney transplant recipients from January 2000 to March 2015 (after which WIT was no longer separately reported), and patients were followed until September 2017. A combined WIT/CIT variable (excluding extreme values) was separately derived for live and deceased donor recipients using cubic splines; for live donor recipients, the reference group was WIT 10 to <23 minutes and CIT >0 to <0.42 hours, and for deceased donor recipients the WIT was 10 to <25 minutes and CIT 1 to <7.75 hours. The adjusted association between combined WIT/CIT and all-cause graft failure (including death) was analyzed using Cox regression. Secondary outcomes included delayed graft function (DGF).

Results

A total of 137 125 recipients were included. For live donor recipients, patients with prolonged WIT/CIT (60 to ≤120 minutes/3.04 to ≤24 hours) had the highest adjusted hazard ratio (HR) for graft failure (HR = 1.61, 95% confidence interval [CI] = 1.14-2.29 relative to the reference group). For deceased donor recipients, a WIT/CIT of 63 to ≤120 minutes/28 to ≤48 hours was associated with an adjusted HR of 1.35 (95% CI = 1.16-1.58). Prolonged WIT/CIT was also associated with DGF for both groups although the impact was more driven by CIT.

Conclusions

Combined WIT/CIT is associated with graft loss following transplantation. Acknowledging that these are separate variables with different determinants, we emphasize the importance of capturing WIT and CIT independently. Furthermore, efforts to reduce WIT and CIT should be prioritized.

Evaluation of renal cold ischemia-reperfusion injury with intravoxel incoherent motion diffusion-weighted imaging and blood oxygenation level-dependent MRI in a rat model

Purpose: Cold ischemia-reperfusion injury (CIRI) is one of the most serious complications following renal transplantation. The current study investigated the feasibility of Intravoxel Incoherent Motion (IVIM) imaging and blood oxygenation level-dependent (BOLD) in the evaluation of different degrees of renal cold ischemia-reperfusion injury in a rat model. Methods: Seventy five rats were randomly divided into three groups (N = 25 for each group): T0: sham-operated group, T2/T4: CIRI groups with different cold ischemia hours (2, 4 h, respectively). The rat model of CIRI group was established by left kidney cold ischemia with right nephrectomy. All the rats received a baseline MRI before the surgery. Five rats in each group were randomly selected to undergo an MRI examination at 1 h, day 1, day 2 and day 5 after CIRI. The IVIM and BOLD parameters were studied in the renal cortex (CO), the outer stripe of the outer medulla (OSOM), and the inner stripe of the outer medulla (ISOM) followed by histological analysis to examine Paller scores, peritubular capillary (PTC) density, apoptosis rate and biochemical indicators to obtain the contents of serum creatinine (Scr), blood urea nitrogen (BUN), superoxide dismutase (SOD) and malondialdehyde (MDA). Results: The D, D*, PF and T2* values in the CIRI groups were lower than those in the sham-operated group at all timepoints (all p < 0.05). The prolonged cold ischemia times resulted in gradually lower D, D*, PF and T2* values (all p < 0.05). The D and T2* values of cortex and OSOM in Group T0 and T2 returned to the baseline level (all p > 0.05) except Group T4. The D* and PF values of cortex, OSOM and ISOM in Group T2 and T4 still remained below the normal levels (all p < 0.05) except Group T0. D, D*, PF and T2* values were strongly correlated with histopathological (Paller scores, PTC density and apoptosis rate) and the biochemistry indicators (SOD and MDA) (|r|>0.6, p < 0.001). D*, PF and T2* values were moderately to poorly correlated with some biochemistry indicators (Scr and BUN) (|r|<0.5, p < 0.05). Conclusion: IVIM and BOLD can serve as noninvasive radiologic markers for monitoring different degrees of renal impairment and recovery after renal CIRI.

Epitope Lability of Phosphorylated Biomarkers of the DNA Damage Response Pathway Results in Increased Vulnerability to Effects of Delayed or Incomplete Formalin Fixation

Phosphorylated biomarkers are crucial for our understanding of drug mechanism of action and dose selection during clinical trials, particularly for drugs that target protein kinases, such as DNA-damage-response (DDR) inhibitors. However, tissue fixation conditions needed to preserve DDR-specific phospho-biomarkers have not been previously investigated. Using xenograft tissues and tightly controlled formalin fixation conditions, we assessed how preanalytical factors affect phosphorylated DDR biomarkers pRAD50(Ser635), ɣH2AX(Ser139), pKAP1(Ser824), and non-phosphorylated biomarkers cMYC and ATM. Cold ischemia times ranged from 15 min to 6 hr, and the fixation duration ranged from 24 hr to 4 weeks. Epitopes pRAD50 and pKAP1 appeared the most labile assessed with staining loss after just 15 min of cold ischemia time, while ATM was more robust showing consistent expression up to 1 hr of cold ischemia. Notably, ɣH2AX expression was lost with formalin fixation over 48 hr. The use of core needle biopsies where possible and novel fixation methods such as the 2-step temperature-controlled formalin approach may improve phosphorylated biomarker preservation; however, practical challenges may affect wider clinical application. The most essential tissue-processing step when downstream analysis includes DDR phosphorylated biomarkers is immediate tissue submersion in formalin, without delay, upon excision from the patient, followed by room temperature fixation for 24 hr.

The effects of thiopental on cold ischemic injury in renal transplantation

INTRODUCTION

One of the most important factors influencing post-transplant success in kidney transplantation is preserving the viability of the organ from removal to transfer into the recipient.

AIM

This study aimed to reduce the energy requirement with thiopental doses administered before organ transplantation, and to increase the organ viability by minimizing the tissue damage during the cold ischemia process.

MATERIALS AND METHODS

Twenty female Wistar albino rats were divided into two groups: control group (group C), and thiopental group (group T). In group C, a midline incision was performed, and the renal artery was isolated under ketamine and xylazine anesthesia. A standard organ storage solution (cooled to +4°C) was used for kidney perfusion. Nephrectomy was applied, and the removed kidneys were placed into +4°C standard organ storage solution and stored at +4°C for 12 hours. Animals in group T were subjected to the procedures explained above under 85 mg/kg thiopental sodium anesthesia. After 12-hour storage, samples from the kidney tissues were fixed in 10% neutral buffered formalin. Histopathological evaluation and apoptosis detection via TUNEL method were performed.

RESULTS

Tubular necrosis was more extensive in group C compared with that in group T and this difference was statistically significant. Similarly, vacuolization was widely observed in group C, and this increase was also statistically significant. For the 'dilatation of Bowman's space' parameter, a significant decrease was observed in group T compared with group C. When the apoptotic index values of both groups were examined, it was seen that they were lower in group T than those in group C. This result was statistically significant.

CONCLUSIONS

These data suggest that thiopental provides protection to the kidney tissue during the cold storage process. Thiopental has been shown to decrease the number of apoptotic cells in the kidney tissue when administered to the donor before organ transplantation, increasing the organ viability.

Does prolonged cold ischemia affect outcomes in donation after cardiac death donor kidney transplants?

    : The purpose of this study was to analyze the combined effect of cold ischemia time (CIT) and donation after cardiac death (DCD, with requisite warm ischemia time, WIT) on kidney transplant (KT) outcomes.

METHODS

Single center retrospective review of DCD KT recipients stratified by CIT.

RESULTS

From 6/08 to 10/20, we performed 446 DCD KTs (115 CIT ≤20, 205 CIT 20-30, 88 CIT 30-40, 38 CIT ≥40 hours). Mean WITs (26/25/27/23 minutes) and KDPI values (59%/55%/55%/59%) were similar while mean CITs (16.4/23.6/33.4/42.5 hours) and pump times (10.3/13.6/16.1/20.4 hours) differed across groups (p < 0.05). With a mean 6-year follow-up, patient survival (84%/84%/74%/84%) was similar. Kidney graft survival (GS) (72%/72%/56%/58%) and death censored GS (DCGS) (82%/80%/63%/67%) rates decreased whereas rates of primary nonfunction (PNF, 0.9%/2.4%/9.1%/7.9%) and delayed graft function (DGF) (36%/48%/50%/69%) increased with longer CIT (≥30 hours, p<0.05). Meaningful years free of dialysis, which we refer to as Allograft Life Years, were achieved in all cohorts (4.5/4.3/3.9/4.3 years per patient transplanted).

CONCLUSION

DCD donor kidneys with prolonged CIT (≥30 hours) are associated with increased rates of DGF and PNF, along with decreased GS and DCGS. Despite this, Allograft Life Years were gained even with longer CITs, demonstrating the utility of using these allografts. This article is protected by copyright. All rights reserved.

Normothermic Machine Perfusion (NMP) of the Liver - Current Status and Future Perspectives

A shortage of available organs for liver transplantation has led transplant surgeons and researchers to seek for innovative approaches in hepatoprotection and improvement of marginal allografts. The most exciting development in the past decade has been continuous mechanical perfusion of livers with blood or preservation solution to mitigate ischemia-reperfusion injury in contrast to the current standard of static cold storage. Two variations of machine perfusion have emerged in clinical practice. During hypothermic oxygenated perfusion the liver is perfused using a red blood cell-free perfusate at 2-10°C. In contrast, normothermic machine perfusion mimics physiologic liver perfusion using a red blood cell-based solution at 35.5-037.5°C, offering a multitude of potential advantages. Putative effects of normothermic perfusion include abrogation of hyperfibrinolysis after reperfusion and inflammation, glycogen repletion, and regeneration of adenosine triphosphate. Research in normothermic machine perfusion focuses on development of biomarkers predicting allograft quality and susceptibility to ischemia-reperfusion injury. Moreover, normothermic perfusion of marginal allografts allows for application of a variety of therapeutic interventions potentially enhancing organ quality. Both methods need to be subjected to translational investigation and evaluation in clinical trials. A clear advantage is transformation of an emergency procedure at night into a planned daytime surgery. Current clinical trials suggest that normothermic perfusion not only increases the use of hepatic allografts but is also associated with milder ischemia-reperfusion injury, resulting in a reduced risk of early allograft dysfunction and less biliary complications, including ischemic cholangiopathy, compared to static cold storage. The aim of this review is to give a concise overview of normothermic machine perfusion and its current applications, benefits, and possible advances in the future.

Impact of donor and prolonged cold ischemia time of neonatal pig pancreas on neonatal pig islet transplant outcome

BACKGROUND

Genetically modified pigs (GMP) have been developed to alleviate the shortage of donors in human islet transplantation and rejection. In this study, we characterized and compared the islets from GalTKO, GalTKO/hCD46, GalTKO/hCD46/hCD39, and wild-type (WT) neonatal pigs.

METHODS

Islets were isolated from GMP and WT pig pancreases that have been packaged with ice pack for at least 24 hours. The difference in gene expression and function of islets were evaluated by microarray analysis and transplantation of islets under the kidney capsule of streptozotocin-induced diabetic immune-deficient mice, respectively. Blood glucose levels of these mice were monitored weekly post-transplantation for >100 days, and islet grafts were collected and evaluated for the presence of endocrine cells.

RESULTS

The genes involved in extracellular components, cell adhesion, glucose metabolism, and inflammatory response are differentially expressed between GMP and WT pig islets. Variation in the ability of pig islets in correcting the diabetic state of the mouse recipients appears to be dependent on the pig donor. In addition, prolonged cold ischemia time had a negative effect on the transplant outcome. All normoglycemic mice were able to respond well to glucose challenge despite the initial differences in the ability of islet transplants to reverse their diabetic state. Islet xenografts of normoglycemic mice contained abundant insulin- and glucagon-positive cells.

CONCLUSION

The effect of GMP and WT neonatal pig islet transplants on hyperglycemia in mice appears to be dependent on the pig donor, and prolonged cold ischemia time negatively affects the neonatal pig islet transplant outcome.

Morphologic assessment of hypertonic citrate adenine, histidine-tryptophan-ketoglutarate, and university of Wisconsin solutions for hypothermic uterus preservation in rats

AIM

Optimizing perfusate for static cold storage is one of the key ways of reducing organ dysfunction and rejection in organ transplantation. Here, we tested the effectiveness of the three different solutions for hypothermic uterus preservation.

METHODS

Twenty rats were divided into four groups, five in each group. Uterine grafts were retrieved and perfused in situ. The uteri were preserved at 4°C in normal saline as control group (group NS), hypertonic citrate adenine (group HCA), histidine-tryptophan-ketoglutarate (group HTK), or university of Wisconsin solutions (group UW) for 0, 12, 24, and 48 h, respectively. HE, electron microscopy, TUNEL staining, and Cleaved Caspase3 immunohistochemical staining were assessed at each time point.

RESULTS

There was no significant difference in the uterine retrieval time, perfusion time, and the amount of perfusion solution in NS, HCA, HTK, and UW groups (p > 0.05). HCA and HTK can well preserve the pathological morphology of rat uterine tissues for up to 24 h, and the apoptosis rates of the two groups are 7.2% and 7.1%, respectively, with no statistical difference (p > 0.05). Still, the protective effect of HTK on the ultrastructure of cells was much better than HCA. There was a significant difference in the apoptosis rate of UW (6.5%), HTK (8.8%), and HCA (9.4%) at 48 h, with mitochondrial and endoplasmic reticulum structure well preserved only in UW.

CONCLUSION

At 4°C, normal saline is not suitable to preserve rat uterus for more than 12 h. The morphologic results would favor the use of HTK rather than HCA for short-term hypothermic uterus preservation (≤24 h). UW is better than HTK and HCA for 48 h hypothermic uterus preservation.

Tannic Acid Improves Renal Function Recovery after Renal Warm Ischemia-Reperfusion in a Rat Model

Background and purpose: Ischemia–reperfusion injury is encountered in numerous processes such as cardiovascular diseases or kidney transplantation; however, the latter involves cold ischemia, different from the warm ischemia found in vascular surgery by arterial clamping. The nature and the intensity of the processes induced by ischemia types are different, hence the therapeutic strategy should be adapted. Herein, we investigated the protective role of tannic acid, a natural polyphenol in a rat model reproducing both renal warm ischemia and kidney allotransplantation. The follow-up was done after 1 week. Experimental approach: To characterize the effect of tannic acid, an in vitro model of endothelial cells subjected to hypoxia–reoxygenation was used. Key results: Tannic acid statistically improved recovery after warm ischemia but not after cold ischemia. In kidneys biopsies, 3 h after warm ischemia–reperfusion, oxidative stress development was limited by tannic acid and the production of reactive oxygen species was inhibited, potentially through Nuclear Factor erythroid-2-Related factor 2 (NRF2) activation. In vitro, tannic acid and its derivatives limited cytotoxicity and the generation of reactive oxygen species. Molecular dynamics simulations showed that tannic acid efficiently interacts with biological membranes, allowing efficient lipid oxidation inhibition. Tannic acid also promoted endothelial cell migration and proliferation during hypoxia. Conclusions: Tannic acid was able to improve renal recovery after renal warm ischemia with an antioxidant effect putatively extended by the production of its derivatives in the body and promoted cell regeneration during hypoxia. This suggests that the mechanisms induced by warm and cold ischemia are different and require specific therapeutic strategies.

Risk Factors for 1-Year Graft Loss After Kidney Transplantation: Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

With expansion of the pool of kidney grafts, through the use of higher-risk donors, and increased attention to donor management strategies, the 1-year graft survival rate is subject to change. It is, therefore, useful to elucidate 1-year graft survival rates by dissecting the characteristics of the low-risk and high-risk kidney transplant cases. The objective of our study was to evaluate factors purported to influence the risk of 1-year graft loss in kidney transplant recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We searched bibliographic databases from 2000 to 2017 and included observational studies that measured the association between donor, recipient, the transplant operation, or early postoperative complications, and 1-year death-censored graft loss.

RESULTS

We identified 35 eligible primary studies, with 20 risk factors amenable to meta-analysis. Six factors were associated with graft loss, with moderate to high degree of certainty: donor age (hazard ratio [HR], 1.11 per 10-year increase; 95% confidence interval [95% CI], 1.04 to 1.18), extended criteria donors (HR, 1.35; 95% CI, 1.28 to 1.42), deceased donors (HR, 1.54; 95% CI, 1.32 to 1.82), number of HLA mismatches (HR, 1.08 per one mismatch increase; 95% CI, 1.07 to 1.09), recipient age (HR, 1.17 per 10-year increase; 95% CI, 1.09 to 1.25), and delayed graft function (HR, 1.89; 95% CI, 1.46 to 2.47) as risk factors for 1-year graft loss. Pooled analyses also excluded, with a high degree of certainty, any associations of cold ischemia time, recipient race, pretransplant body mass index, diabetes, and hypertension with 1-year graft loss.

CONCLUSIONS

Recipient age, donor age, standard versus extended criteria donor, living versus deceased donor, HLA mismatch, and delayed graft function all predicted 1-year graft survival. The effect of each risk factor is small.

Cold Versus Warm Ischemia Robot-Assisted Partial Nephrectomy: Comparison of Functional Outcomes in Propensity-Score Matched "At Risk" Patients

OBJECTIVES

To compare functional outcomes of warm ischemia RPN (wRPN) to cold ischemia RPN (cRPN) in "at risk" patients.

MATERIALS AND METHODS

Retrospective review of institutional database queried for all patients who underwent cRPN/wRPN (January 2007-December 2016). For the study purpose, patients with solitary kidney and/or history of partial nephrectomy and/or multiple tumors and/or preoperative estimated Glomerular Filtration Rate (eGFR) <60 mL/minute were extracted. To reduce inherent biases, groups were matched on key variables related to renal function through a greedy matching algorithm with no replacement. Renal functional outcomes were evaluated by eGFR drops at 1-3 days and at 1, 3, 6, and 12 months postoperatively. A linear mixed effects model was used to assess eGFR at each follow-up who received either cRPN or wRPN. Follow-up was treated as a factor variable to account for nonlinear time trends. Contrast analysis was used to compare cRPN vs wRPN groups at each follow-up, using Sidak-Holm p-value adjustments for multiple comparisons.

RESULTS

Out of 19 cRPN patients and 279 wRPN patients, 14 cRPN patients were finally matched 1:1 with no replacement to 14 wRPN. There was no significant difference in preoperative eGFR for matched patients undergoing cRPN vs wRPN. Since the first postoperative day, cRPN patients had higher eGFR. The difference was statistically significant since the third month postoperatively (mean difference = 18.201, 95% confidence interval [CI]: 1.930-34.472) and remained at both the sixth month (mean difference = 18.839, 95% CI: 2.568-35.109) and the 12th month (mean difference = 21.277, 95% CI: 5.006-37.547) follow-up.

CONCLUSIONS

Accounting for unmodifiable and modifiable factors, in a cohort of highly selected patients "at risk" for postoperative significant decline in renal function after RPN, renal functional outcomes appear to be superior with cold ischemia technique.

A mouse model of renal ischemia-reperfusion injury solely induced by cold ischemia

Transplanted kidneys usually experience several episodes of ischemia, including cold ischemia during allograft storage in preservation solution. However, previous studies focusing on cold renal ischemia were only carried out in vitro or ex vivo. In the present study, we developed and characterized an in vivo mouse model of renal ischemia-reperfusion injury (IRI) induced exclusively by cold ischemia. C57BL/6 mice underwent right kidney nephrectomy, and the left kidney was kept cool with circulating cold saline in a kidney cup, while body temperature was maintained at 37°C. We clamped the renal pedicle and flushed out the blood inside the kidney with cold saline via an opening on the renal vein. The severity of renal IRI was examined with different ischemic durations. We found that the mice with <2 h of cold ischemia exhibited no significant changes in renal function or histopathology; animals with 3 or 4 h of cold ischemia developed into mild to moderate acute kidney injury with characteristic features, including the elevation in plasma creatinine concentration and reduction in glomerular filtration rate and tubular necrosis, followed by a subsequent recovery. However, mice with 5 h of cold ischemia died in a few days with severe acute kidney injury. In summary, we generated a mouse model of renal IRI induced exclusively by cold ischemia, which mimics graft cold storage in preservation solution, and renal function can be evaluated in vivo.

Renal hypothermia during partial nephrectomy for patients with renal tumours: a randomised controlled clinical trial protocol

INTRODUCTION

Partial nephrectomy is a standard of care for non-metastatic renal tumours when technically feasible. Despite the increased use of partial nephrectomy, intraoperative techniques that lead to optimal renal function after surgery have not been rigorously studied. Clamping of the renal hilum to prevent bleeding during resection causes temporary renal ischaemia. The internal temperature of the kidney may be lowered after the renal hilum is clamped (renal hypothermia) in an attempt to mitigate the effects of ischaemia. Our objective is to determine if renal hypothermia during open partial nephrectomy results in improved postoperative renal function at 12 months following surgery as compared with warm ischaemia (no renal hypothermia).

METHODS AND ANALYSES

This is a multicentre, randomised, single-blinded controlled trial comparing renal hypothermia versus no hypothermia during open partial nephrectomy. Due to the nature of the intervention, complete blinding of the surgical team is not possible; however, surgeons will be blinded until the time of hilar clamping. Glomerular filtration will be based on plasma clearance of a radionucleotide, and differential renal function will be based on renal scintigraphy. The primary outcome is overall renal function at 12 months measured by the glomerular filtration rate (GFR). Secondary outcomes include change in GFR, GFR of the affected kidney, change in GFR of the affected kidney, serum creatinine, haemoglobin, spot urine albumin to creatinine ratio, quality of life and postoperative complications. Data will be collected at baseline, immediately postoperatively and at 3, 6, 9 and 12 months postoperatively.

ETHICS AND DISSEMINATION

Ethics approval was obtained for all participating study sites. Results of the trial will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT01529658; Pre-results.

[Nephron-sparing surgery for renal tumors]

This review article presents the data on the epidemiology of renal cell carcinoma and describes minimally invasive surgery for this disease. The authors discuss the use of warm and cold ischemia, vascular microdissection, and artery embolization in renal tumor surgery, and analyze treatment outcomes.

A New Transport Solution for Parathyroid Allotransplantation: Effects on Cell Viability and Calcium-Sensing Receptors

BACKGROUND

Cold ischemia protects organs and tissues by slowing their metabolism, but it also causes ischemic injury. Minimizing cold ischemia has been an important goal in parathyroid auto- and allotransplantation, as well as the transplantation of other major organs. Parathyroid glands are responsible for calcium homeostasis by releasing parathormone (PTH) into the blood circulation. Functionality of a new parathyroid transport solution (NPTS) and effects on cell viability, PTH secretion, and calcium-sensing receptor (CaSR) levels during cold ischemia were evaluated.

MATERIALS AND METHODS

A NPTS was prepared, and the pH was adjusted to a range of 7.2-7.4 and kept at +4°C until use. Seven patients with parathyroid hyperplasia secondary to chronic renal failure who were scheduled to undergo subtotal parathyroidectomy were enrolled in the study. Glands were cold-preserved in NPTS with different time intervals (0, 6, 12, 18, and 24 hours), and then parathyroid cell viability before and after cryopreservation, PTH secretion, and CaSR levels were determined.

RESULTS

The mean cell viability before cryopreservation was 92.7% (range 89.2%-97.2%). There were no significant differences in cell viability rates before and after cryopreservation (p = 0.1168 and p = 0.4085, respectively), and CaSR levels (p = 0.5446) were not significant.

CONCLUSIONS

NPTS is a solution designed specifically for parathyroid tissue transplantation. This patent pending product can support cellular viability and PTH release, as well as protect CaSR functionality for up to 24 hours of cold ischemia.

Uterine Autotransplantation in the Nonhuman Primate With Preservation of the Uterine and Ovarian Vascular Pedicles

PURPOSE

To evaluate the technical feasibility of performing a uterine autotransplantation in the nonhuman primate while preserving the uterine and ovarian vascular pedicles.

METHODS

Eight (n = 8) female baboons at a primate research facility underwent a uterine autotransplant procedure with preservation of the vascular pedicles. The uterine arteries were separated from their amorphous tissue and skeletonized toward the internal iliac arteries bilaterally. A segment of the internal iliac artery was removed bilaterally along with both uterine arteries. Both ovarian veins were preserved to assist with the reperfusion of the uterine organ. Due to larger vascular pedicles in one of the primates, the uterine arteries were separated and reattached directly via end-to-end anastomosis. In another baboon, the deep uterine vein was used as a vascular pedicle rather than the ovarian vein on the left side due to adequate size and visualization.

RESULTS

Immediate tissue reperfusion occurred intraoperatively in 5 of the animals, with slower perfusion in 3 of the animals. Average warm ischemia time was 43.8 minutes while the average cold ischemia time was 174 minutes (2 hours, 54 minutes). Average total surgical time was 5.9 hours. All animals were sheltered into separate cages and monitored for behavior changes and food and drink consumption. Three of the primates expired immediately postoperatively, 2 from severe dehydration and 1 from gastric aspiration.

CONCLUSIONS

This pilot study describes a modified surgical approach for uterine transplants in the nonhuman primate. This surgical technique may be applicable to living and deceased donor uterine transplantation.

The influence of functional warm ischemia time on DCD liver transplant recipients' outcomes

BACKGROUND

Duration of functional warm ischemia (f-WIT) is thought to have a causal effect on outcomes in controlled donation after circulatory death (DCD) liver transplantation (LT).

METHODS

A retrospective cohort study was conducted at five centers. Data were extracted on donor and recipient characteristics, with attention to parameters recorded during withdrawal of life support to in situ cold perfusion. F-WIT was the time elapsed from any of the hemodynamic and oxygenation parameters to the start of in situ cold perfusion. Parameters were as follows: MAP ≤ 50 mm Hg; SBP ≤ 50 mm Hg; and SPO2 ≤ 60%. The primary endpoint was a composite of disseminated ischemic cholangiopathy (IC), primary non-function (PNF), and early graft failure.

RESULTS

35 patients (14%) developed one or more of the primary outcomes. On univariate analysis, older donors and longer WITs were associated with greater likelihood of complications. Of the f-WIT variations analyzed, only f-WIT with SpO2 ≤ 60% was longer among patients with complications. On multivariate analysis, only donor age was a significant predictor of complications.

CONCLUSION

This study demonstrates that, of the f-WITs, f-WIT with SpO2 ≤ 60% is most predictive of post-DCD complications. However, results suggest that there may be an alternate etiology for poor outcomes, and that donor age plays a key role.

Islet Cell Yield Following Remote Total Pancreatectomy With Islet Autotransplant is Independent of Cold Ischemia Time

OBJECTIVES

Total pancreatectomy with islet autotransplantation is increasingly being performed remotely, that is, removing the pancreas in 1 location, isolating the islet cells in another location, then returning the islets to the original location for reimplantation into the patient. We determined the influence of extended cold ischemia time on key clinical outcomes in remote islet autotransplantation.

METHODS

We evaluated patients who underwent remote islet autotransplantation at 2 centers from 2011 to 2014. Patients were divided into 2 groups: those with and those without a decrease in C-peptide greater than 50% from baseline. The primary clinical outcome was the quantity of isolated islet equivalents per kilogram body weight (IEQs/kg).

RESULTS

Twenty-five patients met inclusion criteria; 15 had a decrease in C-peptide greater than 50% from baseline and had lower corresponding IEQs/kg compared with those without a decrease greater than 50% (4045 vs 6654 IEQs/kg, P = 0.01). There was no difference in cold ischemia time between the 2 groups (664 vs 600 minutes, P = 0.25). Daily insulin use at 1 year nearly met statistical significance (25.3 vs 8 U, P = 0.06), as did glycated hemoglobin (8.07 vs 6.69 mmol/L, P = 0.06).

CONCLUSIONS

Cold ischemia time does not influence islet yield in patients undergoing pancreatectomy with remote isolation.

Non-Heart-Beating Donor Heart Transplantation: Breaking the Taboo

Roughly 60% of hearts offered for transplantation are rejected because of organ dysfunction. Moreover, hearts from circulatory-dead patients have long been thought to be non-amenable for transplantation, unlike other organs. However, tentative surgical attempts inspired by the knowledge obtained from preclinical research to recover those hearts have been performed, finally culminating in clinically successful transplants. In this review we sought to address the major concerns in non-heart-beating donor heart transplantation and highlight recently introduced developments to overcome them.

Establishment of a prolonged pancreas preservation model for islet isolation research in mice

Establishing a prolonged pancreas preservation model in a small animal is important for islet isolation research. Use of a rat pancreas model has been reported, but no published reports have used a mouse pancreas for prolonged cold preservation prior to islet isolation. For the model, a mouse is preferred over a rat because of its small size, well-known immune characterization, and variety of gene-modulated models. In the present study, we established a prolonged pancreas preservation model in a mouse for islet isolation research. The collagenase solution was injected successfully after 24 and 48 h cold preservations in University of Wisconsin solution, and islets could be isolated from both groups of preserved pancreata. The islet yields from the control, 24 h preserved, and 48 h preserved pancreata were 183.9 ± 13.9, 128.5 ± 15.5, and 24.6 ± 12.9 per pancreas, respectively. The propidium iodide-positive area assay was significantly increased in both preserved groups, and insulin secretion levels in response to 20.0 mM glucose and stimulation indices were significantly decreased in the 48 h preserved group. Inflammation-related genes mRNA levels were significantly upregulated in the 24 h preserved group, as previously shown in the human model. Thus, this model might be useful for prehuman islet isolation screening research, reserving research using human pancreata for the most promising approaches.

Transgenic overexpression of CD39 protects against renal ischemia-reperfusion and transplant vascular injury

The vascular ectonucleotidases CD39[ENTPD1 (ectonucleoside triphosphate diphosphohydrolase-1), EC 3.6.1.5] and CD73[EC 3.1.3.5] generate adenosine from extracellular nucleotides. CD39 activity is critical in determining the response to ischemia-reperfusion injury (IRI), and CD39 null mice exhibit heightened sensitivity to renal IRI. Adenosine has multiple mechanisms of action in the vasculature including direct endothelial protection, antiinflammatory and antithrombotic effects and is protective in several models of IRI. Mice transgenic for human CD39 (hCD39) have increased capacity to generate adenosine. We therefore hypothesized that hCD39 transgenic mice would be protected from renal IRI. The overexpression of hCD39 conferred protection in a model of warm renal IRI, with reduced histological injury, less apoptosis and preserved serum creatinine and urea levels. Benefit was abrogated by pretreatment with an adenosine A2A receptor antagonist. Adoptive transfer experiments showed that expression of hCD39 on either the vasculature or circulating cells mitigated IRI. Furthermore, hCD39 transgenic kidneys transplanted into syngeneic recipients after prolonged cold storage performed significantly better and exhibited less histological injury than wild-type control grafts. Thus, systemic or local strategies to promote adenosine generation and signaling may have beneficial effects on warm and cold renal IRI, with implications for therapeutic application in clinical renal transplantation.

Calpain is a mediator of preservation-reperfusion injury in rat liver transplantation

Proteases as well as alterations in intracellular calcium have important roles in hepatic preservation-reperfusion injury, and increased calpain activity recently has been demonstrated in liver allografts. Experiments were designed to evaluate (i) hepatic cytosolic calpain activity during different periods of cold ischemia (CI), rewarming, or reperfusion, and (ii) effects of inhibition of calpain on liver graft function using the isolated perfused rat liver and arterialized orthotopic liver transplantation models. Calpain activity was assayed using the fluorogenic substrate Suc-Leu-Leu-Val-Tyr-7-amino-4-methyl coumarin (AMC) and expressed as mean +/- SD pmol AMC released/min per mg of cytosolic protein. Calpain activity rose significantly after 24 hr of CI in University of Wisconsin solution and further increased with longer preservation. Activity also increased within 30 min of rewarming, peaking at 120 min. Increased durations of CI preceding rewarming resulted in significantly higher activity (P < 0.01). Calpain activity increased rapidly upon reperfusion and was significantly enhanced by previous CI (P < 0.01). Calpain inhibition with Cbz-Val-Phe methyl ester significantly decreased aspartate aminotransferase released in the isolated perfused rat liver perfusate (P < 0.05). Duration of survival after orthotopic liver transplantation using livers cold-preserved for 40 hr was also significantly increased (P < 0.05) with calpain inhibitor. In conclusion, calpain proteases are activated during each phase of transplantation and are likely to play an important role in the mechanisms of preservation-reperfusion injury.