Static Cold Storage with Mitochondria-Targeted Hydrogen Sulfide Donor Improves Renal Graft Function in an Ex Vivo Porcine Model of Controlled Donation-after-Cardiac-Death Kidney Transplantation.

The global donor kidney shortage crisis has necessitated the use of suboptimal kidneys from donors-after-cardiac-death (DCD). Using an ex vivo porcine model of DCD kidney transplantation, the present study investigates whether the addition of hydrogen sulfide donor, AP39, to University of Wisconsin (UW) solution improves graft quality. Renal pedicles of male pigs were clamped in situ for 30 min and the ureters and arteries were cannulated to mimic DCD. Next, both donor kidneys were nephrectomized and preserved by static cold storage in UW solution with or without AP39 (200 nM) at 4 °C for 4 h followed by reperfusion with stressed autologous blood for 4 h at 37 °C using ex vivo pulsatile perfusion apparatus. Urine and arterial blood samples were collected hourly during reperfusion. After 4 h of reperfusion, kidneys were collected for histopathological analysis. Compared to the UW-only group, UW+AP39 group showed significantly higher pO2 (p < 0.01) and tissue oxygenation (p < 0.05). Also, there were significant increases in urine production and blood flow rate, and reduced levels of urine protein, serum creatinine, blood urea nitrogen, plasma Na+ and K+, as well as reduced intrarenal resistance in the UW+AP39 group compared to the UW-only group. Histologically, AP39 preserved renal structure by reducing the apoptosis of renal tubular cells and immune cell infiltration. Our finding could lay the foundation for improved graft preservation and reduce the increasingly poor outcomes associated with DCD kidney transplantation.

Carbon monoxide mechanism of protection against renal ischemia and reperfusion injury.

Carbon monoxide is quickly moving past its historic label as a molecule once feared, to a therapeutic drug that modulates inflammation. The development of carbon monoxide releasing molecules and utilization of heme oxygenase-1 inducers have shown carbon monoxide to be a promising therapy in reducing renal ischemia and reperfusion injury and other inflammatory diseases. In this review, we will discuss the developments and application of carbon monoxide releasing molecules in renal ischemia and reperfusion injury, and transplantation. We will review the anti-inflammatory mechanisms of carbon monoxide in respect to mitigating apoptosis, suppressing dendritic cell maturation and signalling, inhibiting toll-like receptor activation, promoting anti-inflammatory responses, and the effects on renal vasculature.

Comparison of Centrifugal and Pulsatile Perfusion to Preserve Donor Kidneys Using Ex Vivo Subnormothermic Perfusion.

Objective We have previously demonstrated benefits of kidney preservation utilizing an oxygenated subnormothermic ex vivo perfusion platform. Herein, we aim to compare pulsatile versus centrifugal (steady and uniform flow) perfusion with the goal of optimizing renal preservation with these devices. Materials and methods: Pig kidneys were procured following 30 min of warm ischemia by cross-clamping both renal arteries. Paired kidneys were cannulated and underwent either: oxygenated pulsatile or centrifugal perfusion using a hemoglobin oxygen carrier at room temperature with our ex vivo machine perfusion platform for 4 hr. Kidneys were reperfused with whole blood for 4 hr at 37° C. Renal function, pathology and evidence of inflammation were assessed post-perfusion. Results: Both pump systems performed equally well with organs exhibiting similar renal blood flow, and function post-reperfusion. Histologic evidence of renal damage using apoptosis staining and acute tubular necrosis scores was similar between groups. This was corroborated with urinary assessment of renal damage (NGAL 1) and inflammation (IL-6), as levels were similar between groups. Conclusion: In our porcine model with added warm ischemia simulating the effects of reperfusion after transplantation, pulsatile perfusion yielded similar renal protection compared with centrifugal perfusion kidney preservation. Both methods of perfusion can be used in ex vivo kidney perfusion systems.

Application of carbon monoxide in kidney and heart transplantation: A novel pharmacological strategy for a broader use of suboptimal renal and cardiac grafts.

Carbon monoxide (CO) was historically regarded solely as a poisonous gas that binds to hemoglobin and reduces oxygen-carrying capacity of blood at high concentrations. However, recent findings show that it is endogenously produced in mammalian cells as a by-product of heme degradation by heme oxygenase, and has received a significant attention as a medical gas that influences a myriad of physiological and pathological processes. At low physiological concentrations, CO exhibits several therapeutic properties including antioxidant, anti-inflammatory, anti-apoptotic, anti-fibrotic, anti-thrombotic, anti-proliferative and vasodilatory properties, making it a candidate molecule that could protect organs in various pathological conditions including cold ischemia-reperfusion injury (IRI) in kidney and heart transplantation. Cold IRI is a well-recognized and complicated cascade of interconnected pathological pathways that poses a significant barrier to successful outcomes after kidney and heart transplantation. A substantial body of preclinical evidence demonstrates that CO gas and CO-releasing molecules (CO-RMs) prevent cold IRI in renal and cardiac grafts through several molecular and cellular mechanisms. In this review, we discuss recent advances in research involving the use of CO as a novel pharmacological strategy to attenuate cold IRI in preclinical models of kidney and heart transplantation through its administration to the organ donor prior to organ procurement or delivery into organ preservation solution during cold storage and to the organ recipient during reperfusion and after transplantation. We also discuss the underlying molecular mechanisms of cyto- and organ protection by CO during transplantation, and suggest its clinical use in the near future to improve long-term transplantation outcomes.

Renal Protection Against Ischemia Reperfusion Injury: Hemoglobin-based Oxygen Carrier-201 Versus Blood as an Oxygen Carrier in Ex Vivo Subnormothermic Machine Perfusion.

BACKGROUND: The optimal method of oxygen delivery to donor kidneys during ex vivo machine perfusion has not been established. We have recently reported the beneficial effects of subnormothermic (22°C) blood perfusion in the preservation of porcine donation after circulatory death kidneys. Since using blood as a clinical perfusate has limitations, including matching availability and potential presence of pathogen, we sought to assess hemoglobin-based oxygen carrier (HBOC-201) in oxygen delivery to the kidney for renal protection. METHODS: Pig kidneys (n = 5) were procured after 30 minutes of warm in situ ischemia by cross-clamping the renal arteries. Organs were flushed with histidine tryptophan ketoglutarate solution and subjected to static cold storage or pulsatile perfusion with an RM3 pump at 22°C for 4 hours with HBOC-201 and blood. Thereafter, kidneys were reperfused with normothermic (37°C) oxygenated blood for 4 hours. Blood and urine were subjected to biochemical analysis. Total urine output, urinary protein, albumin/creatinine ratio, flow rate, resistance were measured. Acute tubular necrosis, apoptosis, urinary kidney damage markers, neutrophil gelatinase-associated lipocalin 1, and interleukin 6 were also assessed. RESULTS: HBOC-201 achieved tissues oxygen saturation equivalent to blood. Furthermore, upon reperfusion, HBOC-201 treated kidneys had similar renal blood flow and function compared with blood-treated kidneys. Histologically, HBOC-201 and blood-perfused kidneys had vastly reduced acute tubular necrosis scores and degrees of terminal deoxynucleotidyl transferase 2'-deoxyuridine, 5'-triphosphate nick end labeling staining versus kidneys treated with cold storage. Urinary damage markers and IL6 levels were similarly reduced by both blood and HBOC-201. CONCLUSIONS: HBOC-201 is an excellent alternative to blood as an oxygen-carrying molecule in an ex vivo subnormothermic machine perfusion platform in kidneys.

Subnormothermic Oxygenated Perfusion Optimally Preserves Donor Kidneys Ex Vivo.

INTRODUCTION: The current methods of preserving donor kidneys in nonoxygenated cold conditions minimally protect the kidney against ischemia-reperfusion injury (IRI), a major source of complications in clinical transplantation. However, preserving kidneys with oxygenated perfusion is not currently feasible due to the lack of an ideal perfusion mechanism that facilitates perfusion with blood at warm temperature. Here, we have designed an innovative renal pump circuit system that can perfuse blood or acellular oxygen carrier under flexible temperatures, pressures, and oxygenation. We have tested this apparatus to study optimal conditions of storage of our porcine model of donation after cardiac death (DCD) kidneys. METHODS: Porcine kidneys were retrieved after 30 minutes of cross-clamping renal pedicles in situ. Cessation of blood mimics postcardiac death in humans and simulates DCD warm ischemic injury. Procured kidneys were flushed and subjected to static cold storage (SCS) for 4 hours. For warm perfusion, kidneys were cannulated for pulsatile oxygenated perfusion with blood:PlasmaLyte for 4 hours at 15 °C, 22 °C, and 37 °C. To mimic posttransplant scenario, all kidneys were reperfused with blood for an additional 4 hours at 37 °C. RESULTS: Compared with all other groups, 22 °C perfusion resulted in significant reduction of acute tubular necrosis (ATN), apoptosis, kidney damage markers, Toll-like receptor signaling, and cytokine production. It was associated with maximal renal blood flow and urine output. Kidneys stored at 15 °C thrombosed within 2 hours under this condition. Martius Scarlet Blue staining confirmed that 22 °C was the optimal temperature to minimize hemorrhage and blood clots. CONCLUSION: Our novel study shows that oxygenated perfusion at near-room-temperature provides optimal donor kidney storage conditions.

Machine preservation of donor kidneys in transplantation.

With increasing demands for 'less than ideal' kidneys for transplantation, machine perfusion of kidneys has been utilized to improve the preservation of kidneys during storage. Hypothermic machine perfusion (HMP) of renal allografts has been shown to reduce delayed graft function rates in both expanded criteria and donation after cardiac death renal allografts. However, the beneficial impact upon long-term graft function is unclear. There has been emerging evidence that both subnormothermic (room temperature) and normothermic machine perfusion (NMP) of allografts have beneficial effects with regards to early graft function, survival and injury in pre-clinical and early clinical studies. Additionally, machine perfusion allows functional assessment of the organ prior to transplantation. Ultimately, the greatest benefit of machine perfusion may be the ability to treat the organ with agents to protect the graft against ischemia reperfusion injury, while awaiting transplantation.

CORM-401 Reduces Ischemia Reperfusion Injury in an Ex Vivo Renal Porcine Model of the Donation After Circulatory Death.

BACKGROUND: Carbon monoxide (CO) inhalation protects organ by reducing inflammation and cell death during transplantation processes in animal model. However, using CO in clinical transplantation is difficult due to its delivery in a controlled manner. A manganese-containing CO releasing molecules (CORM)-401 has recently been synthesized which can efficiently deliver 3 molar equivalents of CO. We report the ability of this anti-inflammatory CORM-401 to reduce ischemia reperfusion injury associated with prolonged cold storage of renal allografts obtained from donation after circulatory death in a porcine model of transplantation. METHODS: To stimulate donation after circulatory death condition, kidneys from large male Landrace pig were retrieved after 1 hour warm ischemia in situ by cross-clamping the renal pedicle. Procured kidneys, after a brief flushing with histidine-tryptophan-ketoglutarate solution were subjected to pulsatile perfusion at 4°C with University of Wisconsin solution for 4 hours and both kidneys were treated with either 200 µM CORM-401 or inactive CORM-401, respectively. Kidneys were then reperfused with normothermic isogeneic porcine blood through oxygenated pulsatile perfusion for 10 hours. Urine was collected, vascular flow was assessed during reperfusion and histopathology was assessed after 10 hours of reperfusion. RESULTS: We have found that CORM-401 administration reduced urinary protein excretion, attenuated kidney damage markers (kidney damage marker-1 and neutrophil gelatinase-associated lipocalin), and reduced ATN and dUTP nick end labeling staining in histopathologic sections. CORM-401 also prevented intrarenal hemorrhage and vascular clotting during reperfusion. Mechanistically, CORM-401 appeared to exert anti-inflammatory actions by suppressing Toll-like receptors 2, 4, and 6. CONCLUSIONS: Carbon monoxide releasing molecules-401 provides renal protection after cold storage of kidneys and provides a novel clinically relevant ex vivo organ preservation strategy.

Ipsilateral renal function preservation following minimally invasive partial nephrectomy: The effect of tumour characteristics and warm ischemic time.

INTRODUCTION: The relative impact of preoperative and perioperative variables on renal function following partial nephrectomy (PN) is controversial. To further investigate, we assess the effects of tumour complexity, warm ischemic time (WIT), and volume of resected renal parenchyma on ipsilateral renal function (IRF) outcomes following minimally invasive PN. METHODS: Of patients who underwent laparoscopic or robotic-assisted PN between 2002 and 2011 at our institution, 99 met our inclusion criteria. The effects of preoperative tumour complexity (using RENAL nephrometry score), perioperative WIT, and pathological tumour volumes on ipsilateral renal function preservation (%IRF) were analyzed. %IRF was defined as the proportion of postoperative to preoperative ipsilateral renal function calculated using MAG3 nuclear renography. RESULTS: Increasing RENAL nephrometry score (RNS) and WIT were independently predictive of inferior %IRF at 6-12-week postoperative followup in univariate and multivariate analyses. Of RNS properties, masses that were endophytic, near the collecting system, or central in location were associated with inferior %IRF, with nearness to collecting system as the strongest predictor; however, RNS was no longer predictive of %IRF in cases requiring more than 30 minutes of WIT. CONCLUSIONS: In renal masses amenable to resection by minimally invasive PN, longer WIT was the most important predictor of inferior %IRF. Although increasing RNS score influenced %IRF, the overall clinical significance of RNS is limited and should not influence operative decision-making in efforts to preserve renal function. Furthermore, small volumes of renal parenchyma can be safely resected without impairment of long-term IRF.

Maximal kidney length predicts need for native nephrectomy in ADPKD patients undergoing renal transplantation.

INTRODUCTION: Native nephrectomy in patients with autosomal dominant polycystic kidney disease (ADPKD) is performed on a case-by-case basis. We determine if pre-transplant maximal kidney length (MKL) can be used to predict ultimate nephrectomy status. METHODS: We performed a retrospective review of ADPKD patients who underwent renal transplantation at our centre between January 2000 and December 2012. Pre-transplant measurements of MKL alone, MKL adjusted for height (HtMKL), weight (WtMKL) and body mass index (BMI-MKL) were each assessed for their predictive ability via a receiver operating characteristic (ROC) curve analysis. RESULTS: In total, 84 patients met our inclusion criteria, of which 17 (20.2%) underwent native nephrectomy. An MKL ROC curve analysis revealed an area under the curve (AUC) of 0.867 (95% confidence interval [CI] 0.775-0.931; p < 0.001). An optimal cutoff criterion of >21.5 cm revealed a sensitivity of 94.1% (95% CI 71.3-99.9) and specificity of 70.1% (95% CI 57.7-80.7) for eventual nephrectomy. The AUC of HtMKL, WtMKL and BMI-MKL ROC curves did not differ significantly from MKL alone. HtMKL improved specificity, but not overall test performance. The determination of the cut-off MKL may be influenced by the single-centre retrospective nature of this analysis, as well as the fact that renal size was determined by ultrasound and not computerized tomography or magnetic resonance imaging. CONCLUSION: MKL in patients with ADPKD is associated with the eventual need for nephrectomy and may be a useful clinical tool to risk stratify these patients and therefore guide patient conversations to a decision to leave the native kidneys in situ.

Emphysematous cystitis and necrotizing fasciitis.

Emphysematous cystitis is an uncommon and often severe infectious condition of the bladder that usually affects women and diabetics. We report a case of a 62-year-old male patient who presented with concomitant emphysematous cystitis and necrotizing fasciitis of the right leg. The patient was initially managed with emergent disarticulation of the right leg. Tissue cultures were positive for Ciprofloxacin-resistant Klebsiella pneumoniae. He was treated with Piperacillin-Tazobactam; however, due to the failure of conservative management of the condition, the patient underwent a cystoprostatectomy with ileal conduit. To our knowledge, this is the first report of concomitant emphysematous cystitis and necrotizing fasciitis requiring aggressive surgical intervention for both diseases.

Renal perfusion pump vs cold storage for donation after cardiac death kidneys: a systematic review.

PURPOSE: Static cold storage is generally used to preserve kidney allografts from deceased donors. Hypothermic machine perfusion may improve the outcome after transplantation but few studies with limited power have addressed this issue. We reviewed evidence of the effectiveness of storing kidneys from deceased donors after cardiac death before transplantation using cold static storage solution or pulsatile hypothermic machine perfusion. MATERIALS AND METHODS: We searched electronic databases in September 2011 for systematic reviews and/or meta-analyses, randomized, controlled trials and studies of other designs that compared delayed graft function and graft survival. Sources included The Cochrane Library, PubMed® and EMBASE®. Studies excluded from review included those that did not discriminate between donation after cardiac death and donation from a neurologically deceased donor. Primary outcomes were delayed graft function and 1-year graft survival. Statistical analysis was done using RevMan (http://ims.cochrane.org/revman). RESULTS: Nine studies qualified for review. Pulsatile perfusion pumped kidneys from donation after cardiac death donors had decreased delayed graft function compared to kidneys placed in cold storage (OR 0.64, 95% CI 0.43-0.95, p = 0.03). There was a trend toward improved 1-year graft survival in the pulsatile perfusion group but statistical significance was not attained (OR 0.74, 95% CI 0.48-1.13, p = 0.17). CONCLUSIONS: Pulsatile machine perfusion of donation after cardiac death kidneys appears to decrease the delayed graft function rate. We noted no benefit in 1-year graft survival. Due to the great heterogeneity among the trials as well as several confounding factors, the overall impact on allograft function and survival requires more study.

Debilitating lower urinary tract symptoms in the post-renal transplant population can be predicted pretransplantation.

BACKGROUND: Overactive bladder and benign prostatic hyperplasia commonly cause lower urinary tract symptoms (LUTS) in the renal transplant (RTx) population. These LUTS may be masked by low urine output and may pose risk to renal allografts after RTx. Our purpose was to determine the frequency and severity of LUTS in RTx patients and to determine if patients at highest risk for LUTS could be predicted by validated questionnaires or other pre-RTx characteristics. METHODS: All patients who underwent RTx between 2005 and 2010 were asked to complete the validated Overactive Bladder Questionnaire based on patient symptoms before RTx and at 6 and 12 months after RTx. Male patients also completed the International Prostate Symptom Score survey. Patient, donor, and RTx characteristics and outcome data were collected. RESULTS: Of 466 RTx recipients, 23.8% responded and 89 patients were eligible for participation in the study. LUTS were common both before and after RTx as measured by the Overactive Bladder Questionnaire and International Prostate Symptom Score. Pre-RTx survey scores were predictive of moderate to severe post-RTx LUTS (relative risk, 4.1-18.0; P≤0.05). Low urine output of less than 250 mL per day was also predictive of moderate to severe post-RTx LUTS (relative risk, 2.9-5.9; P<0.02). CONCLUSIONS: Validated questionnaires and low urine output before transplantation may be used to identify patients at highest risk for LUTS after RTx. Identification of at risk patients would allow earlier initiation of treatment strategies to improve patient quality of life.

Carbon monoxide releasing molecules inhibit cell death resulting from renal transplantation related stress.

PURPOSE: Organ cold storage and subsequent transplantation are associated with significant ischemia-reperfusion injury, leading to cell death, graft inflammation and decreased graft function. MATERIALS AND METHODS: CORM-3s reduce oxidative stress and prevent inflammation in kidneys stored at 4C and subsequently transplanted. Graft survival and function are markedly improved compared to kidneys preserved and stored in University of Wisconsin solution alone. We determined whether CORM-3 has direct antiapoptotic effects on in vitro preparations of human HUVECs exposed to anoxic conditions. We also determined whether direct administration of CORM-3 to renal grafts before and/or after cold storage would prevent renal damage during the transplantation process. RESULTS: CORM-3 supplementation led to a significantly increased frequency of live cells (mean ± SD 72.3% ± 1.9%, p <0.01), reduced apoptosis (14.9% ± 6.1%, p <0.01) and decreased mitochondrial transmembrane potential (40.2% ± 7.2%, p <0.05) in HUVECs exposed to 20 hours of cold storage compared to controls (11.6% ± 3.5%, 82.2% ± 2.3% and 78.2% ± 3.2%, respectively). In keeping with this antiapoptotic effect CORM-3 supplementation led to a mean 7.4 ± 2.1-fold up-regulation in Bcl-2 gene expression. CORM-3 supplementation in standard preservation solution was most beneficial at initial ischemic injury and before cold storage exposure. However, additional reflushing before vascular reperfusion showed an additive benefit to graft survival and function after transplantation. This was confirmed by decreased glomerular and tubular necrosis, and apoptosis in double flushed grafts. CONCLUSIONS: CORM-3 supplementation in standard University of Wisconsin solution has a significant impact on decreasing cellular and graft injury, and improving survival through its antiapoptotic effects, which are likely mediated through mitochondrial membrane stabilization.

Should peritoneal dialysis catheters be removed at the time of kidney transplantation?

BACKGROUND: : Delayed graft function (DGF) following transplantation necessitates support in the form of hemodialyis (HD) or peritoneal dialysis (PD). However, post-transplant PD-related complication and failure rates are unknown. METHODS: : We studies patients who were on PD at the time of kidney transplantation over a 4-year period at two separate institutions. RESULTS: : Of the 137 PD patients, 19 had their catheters removed at the time of transplant. Of the remaining 118 patients, 89% had immediate graft function. PD-related complications in this group included peritonitis (n=5), catheter-related infections (n=2) and emergency laparotomy (n=1). Of the 15 patients requiring post-transplant PD, 33% developed peritonitis and 20% had fluid-leaks necessitating HD. Overall, leaving a PD catheter in situ post- transplantation is associated with 7% rate of peritonitis versus 0% if removed (p < 0.05). CONCLUSIONS: : PD catheter removal should be considered at the time of renal transplantation, as postoperative PD-related failure/complication rates are high.

Total pelvic exenteration for rectal cancer: outcomes and prognostic factors.

BACKGROUND: To perform complete resection of locally advanced and recurrent rectal carcinoma, total pelvic exenteration (TPE) may be attempted. We identified disease-related outcomes and prognostic factors. METHODS: We conducted a single-centre review of patients who underwent TPE for rectal carcinoma over a 10-year period. RESULTS: We included 28 patients in our study. After a median follow-up of 35 months, 53.6% of patients were alive with no evidence of disease. The 3-year actuarial disease-free and overall survival rates were 52.2% and 75.1%, respectively. On univariate analysis, recurrent disease, preoperative body mass index greater than 30 and lymphatic invasion were poor prognostic factors for disease-free survival, and only lymphatic invasion predicted overall survival. Additionally, multivariate analysis identified lymphatic invasion as an independent poor prognostic factor for disease-free survival in this patient population with locally advanced and recurrent rectal carcinoma. CONCLUSION: Despite the significant morbidity, TPE can provide long-term survival in patients with rectal carcinoma. Additionally, lymphatic invasion on final pathology was an independent prognostic factor for disease-free survival.

Extracapsular versus intracapsular allograft nephrectomy: impact on allosensitization and surgical outcomes.

INTRODUCTION: Our objective was to compare the impact of extra-capsular (ECAN) versus intracapsular allograft nephrectomy (ICAN) on allosensitization and surgical outcomes. METHODS: Between 1990 and 2004, 96 allograft nephrectomies were performed at our institution. Of these, 29 procedures were performed within 1 month of the transplant and were therefore omitted from analysis. Overall, the results of 44 ECAN and 23 ICAN were reviewed. RESULTS: The mean operative times were 110.9 versus 130.4 min for ICAN versus ECAN (p = 0.02) and the estimated blood loss was 226 mL for ICAN versus 483 mL for ECAN (p = 0.004). Intraoperative and postoperative complications were low using either technique and differences were not statistically significant. Overall, the preoperative to postoperative change in the percentage of panel reactive antibody was +2.1% for ICAN versus +1.2% for ECAN (NS) at 3 to 12 months postoperatively, respectively (NS). The percentage of patients relisted was 33.3% versus 54.3% (NS), and the percentage of patients re-transplanted once relisted was also very similar: 63.2% for ECAN versus 66.7% for ICAN (NS), after a mean follow-up of 4.5 and 8.4 years, respectively. CONCLUSIONS: ICAN can be performed with shorter operative times and less blood loss versus the extracapsular approach. As well, this operative approach does not appear to affect allosensitization and the ability to re-transplant patients.