CD47 blockade reduces ischemia/reperfusion injury in murine heart transplantation and improves donor heart preservation

BACKGROUND

Myocardial ischemia-reperfusion injury (MIRI) is an important cause of early dysfunction and exacerbation of immune rejection in transplanted hearts. The integrin-related protein CD47 exacerbates myocardial ischemia-reperfusion injury by inhibiting the nitric oxide signaling pathway through interaction with thrombospondin-1 (TSP-1). In addition, the preservation quality of the donor hearts is a key determinant of transplant success. Preservation duration beyond four hours is associated with primary graft dysfunction. We hypothesized that blocking the CD47-TSP-1 system would attenuate ischemia-reperfusion injury in the transplanted heart and, thus, improve the preservation of donor hearts.

METHODS

We utilized a syngeneic mouse heart transplant model to assess the effect of CD47 monoclonal antibody (CD47mAb) to treat MIRI. Donor hearts were perfused with CD47mAb or an isotype-matched control immunoglobulin (IgG2a) and were implanted into the abdominal cavity of the recipients after being stored in histidine-tryptophan-ketoglutarate (HTK) solution at 4 °C for 4 h or 8 h.

RESULTS

At both the 4-h and 8-h preservation time points, mice in the experimental group perfused with CD47mAb exhibited prolonged survival in the transplanted heart, reduced inflammatory response and oxidative stress, significantly decreased inflammatory cell infiltration, and fewer apoptosis-related biomarkers.

CONCLUSION

The application of CD47mAb for the blocking of CD47 attenuates MIRI as well as improves the preservation and prognosis of the transplanted heart in a murine heart transplant model.

Cinnamaldehyde protects donor heart from cold ischemia-reperfusion injury via the PI3K/AKT/mTOR pathway

With the growing shortage of organs, improvements in donor organ protection are needed to meet the increasing demands for transplantation. Here, the aim was to investigate the protective effect of cinnamaldehyde against ischemia-reperfusion injury (IRI) in donor hearts exposed to prolonged cold ischemia. Donor hearts were harvested from rats pretreated with or without cinnamaldehyde, then subjected to 24 h of cold preservation and 1 h of ex vivo perfusion. Hemodynamic changes, myocardial inflammation, oxidative stress, and myocardial apoptosis were evaluated. The PI3K/AKT/mTOR pathway involved in the cardioprotective effects of cinnamaldehyde was explored through RNA sequencing and western blot analysis. Intriguingly, cinnamaldehyde pretreatment remarkably improved cardiac function through increasing coronary flow, left ventricular systolic pressure, +dp/dtmax, and -dp/dtmax, decreasing coronary vascular resistance and left ventricular end-diastolic pressure. Moreover, our findings indicated that cinnamaldehyde pretreatment protected the heart from IRI by alleviating myocardial inflammation, attenuating oxidative stress, and reducing myocardial apoptosis. Further studies showed that the PI3K/AKT/mTOR pathway was activated after cinnamaldehyde treatment during IRI. The protective effects of cinnamaldehyde were abolished by LY294002. In conclusion, cinnamaldehyde pretreatment alleviated IRI in donor hearts suffering from prolonged cold ischemia. Cinnamaldehyde exerted cardioprotective effects through the activation of the PI3K/AKT/mTOR pathway.

Establishment of a risk prediction model for prolonged mechanical ventilation after lung transplantation: a retrospective cohort study

BACKGROUND

Prolonged mechanical ventilation (PMV), mostly defined as mechanical ventilation > 72 h after lung transplantation with or without tracheostomy, is associated with increased mortality. Nevertheless, the predictive factors of PMV after lung transplant remain unclear. The present study aimed to develop a novel scoring system to identify PMV after lung transplantation.

METHODS

A total of 141 patients who underwent lung transplantation were investigated in this study. The patients were divided into PMV and non-prolonged ventilation (NPMV) groups. Univariate and multivariate logistic regression analyses were performed to assess factors associated with PMV. A risk nomogram was then established based on the multivariate analysis, and model performance was further examined regarding its calibration, discrimination, and clinical usefulness.

RESULTS

Eight factors were finally identified to be significantly associated with PMV by the multivariate analysis and therefore were included as risk factors in the nomogram as follows: the body mass index (BMI, P = 0.036); primary diagnosis as idiopathic pulmonary fibrosis (IPF, P = 0.038); pulmonary hypertension (PAH, P = 0.034); primary graft dysfunction grading (PGD, P = 0.011) at T₀; cold ischemia time (CIT P = 0.012); and three ventilation parameters (peak inspiratory pressure [PIP, P < 0.001], dynamic compliance [Cdyn, P = 0.001], and P/F ratio [P = 0.015]) at T₀. The nomogram exhibited superior discrimination ability with an area under the curve of 0.895. Furthermore, both calibration curve and decision-curve analysis indicated satisfactory performance.

CONCLUSION

A novel nomogram to predict individual risk of receiving PMV for patients after lung transplantation was established, which may guide preventative measures for tackling this adverse event.

Prediction model of delayed graft function based on clinical characteristics combined with serum IL-2 levels

BACKGROUND

Kidney transplantation is an effective treatment for end-stage renal disease (ESRD). Delayed graft function (DGF) is a common complication after kidney transplantation and exerts substantial effects on graft function and long-term graft survival. Therefore, the construction of an effective model to predict the occurrence of DGF is particularly important.

METHODS

Seventy-one patients receiving their first kidney transplant at the First Affiliated Hospital of Nanchang University from October 2020 to October 2021 were enrolled in the discovery cohort. Based on clinical characteristics and serum markers, a logistic regression model was used to simulate the risk of DGF in the discovery cohort. The DGF prediction model was named the prediction system and was composed of risk factors related to DGF. Thirty-two patients receiving a kidney transplant at the First Affiliated Hospital of Nanchang University from October 2021 to February 2022 were enrolled in the validation cohort. The validation cohort was used to verify the accuracy and reliability of the prediction model.

RESULTS

Cold ischemia time (CIT), donor history of diabetes mellitus, donor interleukin-2 (IL-2) level and donor terminal creatinine level constitute the prediction system. In the validation test, the area under the receiver operating characteristic curve (AUC) was 0.867 for the prediction system, and good calibration of the model was confirmed in the validation cohort.

CONCLUSIONS

This study constructed a reliable and highly accurate prediction model that provides a practical tool for predicting DGF. Additionally, IL-2 participates in the kidney injury process and may be a potential marker of kidney injury.

Analysis of risk factors for donation after circulatory death kidney transplantation in Japan

Background

In Japan, donations after circulatory death kidney transplantation are widely performed due to legislation delays. The number of donations after brain death kidney transplantations is increasing, but the target remains unmet. We reviewed the outcomes of donation after circulatory death in Japan.

Methods

We analyzed 2923 deceased kidney transplantations (2239: donation after circulatory death (DCD), 684: donation after brain death (DBD)) performed in Japan from 2000 to 2019. The outcomes of the DCD and DBD groups were compared. We examined the risk factors for graft loss in the DCD group.

Results

The 5-year patient survival and death-censored graft survival rates of the DCD group, obtained by propensity score matching, were 93.6% and 95.2%, respectively, which were equivalent to 94.2% and 93.8%, respectively, obtained in the DBD group. Older donors (≥ 50 years) and prolonged cold ischemia time (≥ 12 h) were risk factors for graft loss; in the presence of these, graft survival was lower in the DCD group.

Conclusions

Older donors and prolonged cold ischemia time reduced graft survival in the DCD group. Proper evaluation of donors and careful preparation for transplant surgery are, therefore, essential to ensure good transplant outcomes.

THE COST OF KIDNEY TRANSPLANTATION AT THE MERKUR UNIVERSITY HOSPITAL, ZAGREB, CROATIA

The aim was to determine the cost of hospitalization for a transplant procedure and identify the independent variables associated with the cost of transplantation. The investigation was designed as a retrospective single-center cohort study conducted at a tertiary university hospital transplant center in Zagreb, Croatia. The study included 219 consecutive kidney recipients transplanted during the 2007-2013 period at the Merkur University Hospital. There were 141 male and 78 female patients having undergone kidney transplantation during the study period. The majority of kidney transplants were from a deceased donor (n=179), while 40 were from a living donor. The mean cost of a transplantation was 86,140±42,240 HRK (11,460±5,600 €), ranging from 29,000 HRK (3,860 €) to 408,000 HRK (54,000 €). In the bivariate analysis, the variables associated with the cost of transplantation were the length of hospital stay, delayed graft function, death of the patient, graft loss, use of steroids, and death-censored graft loss. In the multivariate analysis, delayed graft function was the only statistically significant variable for the cost of transplantation. Since only delayed graft function had an impact on the cost of transplantation in this study, certain steps such as shortening of the cold ischemia time (better organization of organ transport), better education of family members for living donors, and higher percentage of patients on peritoneal dialysis should be taken to lower the percentage of delayed graft function.

[Percutaneous liver biopsy before organ removal-Impact on organ allocation and costs in liver transplantation]

Hintergrund

Der Stellenwert und die Sicherheit einer perkutanen Leberbiopsie (PLB) bei hirntoten Spendern vor Organentnahme sowie der Einfluss der PLB auf die Organallokation und die Kosten im Rahmen der Lebertransplantation (LT) in der Eurotransplant-Region (ET), werden weiterhin diskutiert.

Material und Methoden

Eine perkutane Leberbiopsie vor Organentnahme erfolgte bei 36 hirntoten Spendern. Die Komplikationsrate, Spendercharakteristika, Ultraschallbefunde, die makroskopische Einschätzung und die histologischen Ergebnisse der PLB wurden analysiert. Zusätzlich wurde eine landesweite Umfrage unter 11 Lebertransplantationsexperten durchgeführt. Der Bedarf einer PLB und ihre Auswirkungen auf den Prozess der Organallokation wurden evaluiert. Mögliche Kosteneinsparungen wurden für verschiedene Szenarien auf der Grundlage von Kostendaten der Deutschen Stiftung Organtransplantation berechnet.

Ergebnisse

Es wurden keine Komplikationen durch die PLB beobachtet. Die Umfrage ergab, dass das Ergebnis der PLB einen erheblichen Einfluss auf die Allokation von Spenderorganen hat, insbesondere bei solchen mit „extended donor criteria (EDC)“. Die Kostenberechnung ergab ein enormes Kosteneinsparungspotenzial durch eine optimierte Allokation und die Vermeidung unnötiger Organentnahmen.

Schlussfolgerung

Die PLB ist ein sicheres Verfahren und besitzt ein enormes Potenzial für die Optimierung der Organallokation vor Organentnahme durch eine Reduzierung der kalten Ischämiezeit, Vermeidung unnötiger Verwerfungen von Spenderorganen sowie Kosteneinsparungen. Die klinische Relevanz und der Einfluss der PLB auf die Organallokation konnte durch unsere Daten herausgestellt werden.

The impact of major extended donor criteria on graft failure and patient mortality after liver transplantation

INTRODUCTION

Numerous extended donor criteria (EDC) have been identified in liver transplantation (LT), but different EDC have different impacts on graft and patient survival. This study aimed to identify major EDC (maEDC) that were best able to predict the outcome after LT and to examine the plausibility of an allocation algorithm based on these criteria.

METHODS

All consecutive LTs between 12/2006 and 03/2014 were included (n = 611). We analyzed the following EDC: donor age > 65 years, body mass index > 30, malignancy and drug abuse history, intensive care unit stay/ventilation > 7 days, aminotransferases > 3 times normal, serum bilirubin > 3 mg/dL, serum Na⁺ > 165 mmol/L, positive hepatitis serology, biopsy-proven macrovesicular steatosis (BPS) > 40%, and cold ischemia time (CIT) > 14 h. We analyzed hazard risk ratios of graft failure for each EDC and evaluated primary non-function (PNF). In addition, we analyzed 30-day, 90-day, 1-year, and 3-year graft survival. We established low- and high-risk graft (maEDC 0 vs. ≥ 1) and recipient (labMELD < 20 vs. ≥ 20) groups and compared the post-LT outcomes between these groups.

RESULTS

BPS > 40%, donor age > 65 years, and CIT > 14 h (all p < 0.05) were independent predictors of graft failure and patient mortality and increased PNF, 30-day, 90-day, 1-year, and 3-year graft failure rates. Three-year graft and patient survival decreased in recipients of ≥ 1 maEDC grafts (all p < 0.05) and LT of high-risk grafts into high-risk recipients yielded worse outcomes compared with other groups.

CONCLUSION

Donor age > 65 years, BPS > 40%, and CIT > 14 h are major EDC that decrease short and 3-year graft survival, and 3-year patient survival. An allocation algorithm based on maEDC and labMELD is therefore plausible.

Visual quality assessment of the liver graft by the transplanting surgeon predicts postreperfusion syndrome after liver transplantation: a retrospective cohort study

Background

The discrepancy between demand and supply for liver transplants (LT) has led to an increased transplantation of organs from extended criteria donors (ECD).

Methods

In this single center retrospective analysis of 122 cadaveric LT recipients, we investigated predictors of postreperfusion syndrome (PRS) including transplant liver quality categorized by both histological assessment of steatosis and subjective visual assessment by the transplanting surgeon using multivariable regression analysis. Furthermore, we describe the relevance of PRS during the intraoperative and postoperative course of LT recipients.

Results

53.3% (n = 65) of the patients suffered from PRS. Risk factors for PRS were visually assessed organ quality of the liver grafts (acceptable: OR 12.2 [95% CI 2.43–61.59], P = 0.002; poor: OR 13.4 [95% CI 1.48–121.1], P = 0.02) as well as intraoperative norepinephrine dosage before reperfusion (OR 2.2 [95% CI 1.26–3.86] per 0.1 μg kg^− 1 min^− 1, P = 0.01). In contrast, histological assessment of the graft was not associated with PRS. LT recipients suffering from PRS were hemodynamically more instable after reperfusion compared to recipients not suffering from PRS. They had lower mean arterial pressures until the end of surgery (P < 0.001), received more epinephrine and norepinephrine before reperfusion (P = 0.02 and P < 0.001, respectively) as well as higher rates of continuous infusion of norepinephrine (P < 0.001) and vasopressin (P = 0.02) after reperfusion. Postoperative peak AST was significantly higher (P = 0.001) in LT recipients with PRS. LT recipients with intraoperative PRS had more postoperative adverse cardiac events (P = 0.05) and suffered more often from postoperative delirium (P = 0.04).

Conclusions

Patients receiving ECD liver grafts are especially prone to PRS. Anesthesiologists should keep these newly described risk factors in mind when preparing for reperfusion in patients receiving high-risk organs.

Renoprotective Procedures with a Cold Ischemia Time of <60 min Minimize the Deterioration of Kidney Function in Open Nephron-Sparing Surgery for Renal Cell Carcinoma

INTRODUCTION

We evaluated whether nephron sparing surgery (NSS) combined with meticulous suturing of the cut stump under clamping with cooling is beneficial for oncological outcomes and also assessed the relationship between cold ischemia time and deterioration of renal function.

METHODS

One hundred and six patients with renal cell carcinoma (RCC) were subjected to this procedure. Oncological outcomes and renal function according to the estimated glomerular filtration rate (eGFR) and the tubular excretion rate on renoscintigraphy before and at 12 months after surgery were evaluated.

RESULTS

Cancer recurrences were observed in 2 patients with past history of RCC; however, no patient died of cancer. Renal function was evaluated depending on 4 different ischemia times. All groups did not show a remarkable decrease of renal function in terms of eGFR. Renoscintigraphy revealed the deterioration of the affected kidney in patients with >60 min ischemia.

CONCLUSION

The renoprotective procedure of NSS provided maximum preservation of renal function until 60 min of cold ischemia time.

Predictors of intra-abdominal coagulopathic hemorrhage after living donor liver transplantation

BACKGROUND

Results of preoperative conventional coagulation assays are a poor predictor of hemorrhage after liver transplantation. In this study, we evaluated the factors that are predictive of intra-abdominal coagulopathic hemorrhage after living donor liver transplantation surgery.

METHODS

During the period from January 2009 to December 2012, 118 adults underwent living donor liver transplantation (LDLT) in our institution. Of those patients, 18 (15.3%) developed intra-abdominal coagulopathic hemorrhage (n = 7) or hemorrhage due to non-coagulopathic causes (n = 11) that required emergency medical, radiological, or surgical intervention within the first month after LDLT. Possible predictors of postoperative coagulopathic hemorrhage included donor-related factors, age, body mass index, MELD score, INR value, intra-operative blood transfusion, graft/recipient weight ratio, anhepatic phase, cold ischemia time, operative time, APACHE II score, onset of re-bleeding, and hemoglobin levels during rebleeding episodes.

RESULTS

There were no differences in any of the variables between the two groups (coagulopathic and noncoagulopathic hemorrhage) except for cold ischemia time. We found that cold ischemia time was significantly longer in patients with postoperative coagulopathic hemorrhage (160.50 ± 45.02 min) than in patients with hemorrhage due to non-coagulopathic causes (113.55 ± 29.31 min; P = 0.027).

CONCLUSION

Prolonged cold ischemia time is associated with postoperative intra-abdominal coagulopathic hemorrhage in patients after LDLT. It is, therefore, necessary to shorten the cold ischemia time in order to reduce the risk of postoperative intra-abdominal hemorrhage due to coagulopathic causes.

Deceased donor renal transplantation at army hospital research and referral: Our experience

CONTEXT

In India, there are a large number of end-stage renal disease (ESRD) patients waiting for renal transplant. Deceased donor organ transplantation (DDOT) is the possible solution to bridge the disparity between organ supply and demand. The concept of expanded criteria donors (ECDs) was developed to combat the huge discrepancy between demand and organ availability. However, ECD kidneys have a higher propensity for delayed graft function (DGF), and therefore worse long-term survival. We present our experience of deceased donor renal transplantation.

AIMS

We report single centre experience on DDOT including ECDs vis-à-vis patient/graft survival, graft function in terms of serum creatinine (SCr), rejection episodes, and delayed graft function in 44 DDOT.

MATERIALS AND METHODS

Between August 1998 and April 2011, 44 renal transplants from 35 deceased donors were performed, of which 37.2% were expanded criteria donors. Results were analyzed in terms of age of donor, terminal SCr, graft ischemia time, graft function, post-transplant complications, and graft and patient survival. All recipients received sequential triple drug immunosuppression and induction with rabbit antithymocyte globulin (rATG). The induction is commenced by giving first dose of rATG intraoperatively (dose 1.5 mg/kg) and subsequent rATG infusions were administered daily for a minimum of 5 and maximum of 7 doses depending on initial graft function.

RESULTS

We have been able to achieve a mean cold ischemia time of 6.25 ± 2.55 h due to the coordinated team efforts. Delayed graft function occurred in 34% patients and 31.8% had prolonged drainage. There were no urinary leaks. Seven (16%) patients had biopsy-proven rejection episodes, all of which were reversed with treatment. Two patients underwent graft nephrectomy. One of these was due to hyperacute rejection and another due to anastomotic hemorrhage. One-year graft survival was 92.4% and the patient survival was 83.8%.

CONCLUSION

Deceased donor renal transplants have satisfactory graft function and patient survival despite the high incidence of delayed graft function. Retrieving kidneys from marginal donors can add to the donor pool.