Relevance of KDPI value and acute rejection on kidney transplant outcomes in recipients with delayed graft function - a retrospective study

Utility of Deceased Expanded-Criteria Donors in Kidney Transplantation: A Single-Center Experience

Purpose: The success of solid organ transplantation and the consequent increase in the patients on the waiting list has led to an increased utilization of donor kidneys with a high kidney donor profile index (KDPI)/expanded criteria. In our study, patients who underwent transplantation based on the standard and expanded donor criteria were compared in terms of factors affecting graft survival. Data of patients who underwent transplantation from cadavers with standard and extended criteria (SCD, ECD) between 01 July 2011 and 30 June 2016 were evaluated retrospectively. Donor characteristics, treatment type, response and graft characteristics, 1st-, 3rd-, and 5th-year graft survival, and acute rejection rates were analyzed retrospectively. Recent findings: In terms of the causes of death, cerebrovascular accidents were more common in the ECD group (p < 0.001). Hypertension and diabetes were more common in both donor groups and were detected more frequently in recipients in the ECD group (p < 0.001). The absence of mycophenolate mofetil (MMF) use and the presence of an acute rejection attack adversely affected graft survival at the end of the 1st, 3rd, and 5th years. Summary: The utilization of expanded criteria donors is widespread. Appropriate monitoring of patients undergoing immunosuppressive therapy, especially using mycophenolate mofetil (MMF) and the presence of acute rejection, affect graft survival.

Assessment of the Effect of Brain Death Etiologies on Organs Transplanted Per Donor

OBJECTIVES

We assessed effects of brain death etiology on organ donation, particularly focusing on the number of organs transplanted per donor.

MATERIALS AND METHODS

We evaluated 934 actual donors from 982 brain death cases at our center from April 2016 to July 2023. We analyzed donor cause of death, donor age, sex, blood group, time to consent, and hospital characteristics.

RESULTS

Among 934 actual brain death donors (63.6% male), mean age was 41.44 years. Cause of death was nontraumatic intracranial hemorrhage in 43.3% of cases, followed by trauma, hypoxia, cerebrovascular accident, toxicity, and brain tumor, respectively. Kidney, liver, heart, and lung donations occurred in 696 cases (74.5%), 809 (86.6%), 146 (15.6%), and 25 (3.4%), respectively. Donor cause of death significantly affected kidney donation (P < .001), with highest rates in trauma (83.7%), followed by brain tumors. Although cause of death did not affect liver transplant rates (P = .26), the highest rate was associated with trauma (89.9%), followed by toxicity. Difference in heart transplant rates among different causes of death was significant (P < .001), with highest rates in trauma cases. Similar to liver transplant, lung transplant was similar among different causes of death (P = .3). Organs transplanted per donor averaged 2.52 ± 1.13, with highest numbers associated with trauma (2.88 ± 1.07), followed by drug toxicity, brain tumors, hypoxia, nontraumatic intracranial hemorrhage, and cerebrovascular accident (P < .001). Compared with trauma, differences in organs transplanted per donor were significant for nontraumatic intracranial hemorrhage (mean difference 0.56; 95% CI, 0.39-0.74; P < .001), cerebrovascular accident (mean difference 0.58; 95% CI, 0.29-0.87; P < .001), and hypoxia (mean difference 0.50; 95% CI, 0.26-0.76; P = .002).

CONCLUSIONS

Understanding how cause of death influences donation can help improve organ donation practices and potentially increase the number of organs available for transplant.

Precision in Immune Management: Balancing Steroid Exposure, Rejection Risk, and Infectious Outcomes in Adult Kidney Transplant Recipients

BACKGROUND/OBJECTIVES

With kidney transplant immunosuppression, physicians must balance preventing rejection with minimizing infection and malignancy risks. Steroids have been a mainstay of these immunosuppression regimens since the early days of kidney transplantation, yet their risks remain debated. Our study looks at the clinical outcomes of patients undergoing early steroid withdrawal (ESW) vs. steroid continuous (SCI) maintenance immunosuppression in adult kidney transplant recipients.

METHODS

A retrospective case-control study, utilizing propensity score-matching, was performed using the US Collaborative Network Database within TriNetX to evaluate renal transplant outcomes at one year in first-time kidney transplant adult patients (>18 years old) who were prescribed an ESW regimen (no steroids after post-transplant day 7 with maintenance tacrolimus [tac] + mycophenolic acid [MMP]/mycophenolate mofetil [MMF]) vs. SCI (tac + MMF/MMP + prednisone). Cohorts were matched on demographics, comorbidities, previously described risk factors for rejection, and induction immunosuppression. Primary outcomes included viral infections, pyelonephritis, and sepsis. Secondary outcomes included renal transplant rejection, death-censored allograft failure (eGFR < 15 mL/min), patient mortality, delayed graft function, and diabetes mellitus.

RESULTS

A total of 2056 patients were in each cohort after matching (mean age: 50.7-51 years, 17.9-20.0% African American, 60-60.6% male.) The SCI cohort had a significantly higher cumulative incidence of composite viremia (18 vs. 28.1%, ESW vs. SCI, p < 0.01) driven by CMV, EBV, and BK virus. Post-transplant diabetes mellitus was significantly higher in the SCI cohort (3.21% vs. 5.49%, ESW vs. SCI, p < 0.01). Delayed graft function was also higher in the SCI cohort (19.55% vs. 22.79%, ESW vs. SCI, p < 0.01). Pyelonephritis (2.3 vs. 4.91%, ESW vs. SCI, p < 0.01) and sepsis (2.15 vs. 5.95%, ESW vs. SCI, p < 0.01) were higher in the SCI cohort. Rejection rates were similar between ESW and SCI (29 vs. 31%, ESW vs. SCI, p = 0.41). There were significantly higher incidences of graft failure (4.9 vs. 9.9%, ESW vs. SCI, p < 0.01) and mortality (0.8 vs. 2.1%, ESW vs. SCI, p < 0.01) in the SCI cohort.

CONCLUSIONS

This well-matched case-control study suggests that ESW is associated with lower infectious outcomes, mortality, and graft failure without increasing rejection risk, supporting the potential benefits of ESW in kidney transplant patients.

Characteristics of Delayed Graft Function and Long-Term Outcomes After Kidney Transplantation From Brain-Dead Donors: A Single-Center and Multicenter Registry-Based Retrospective Study

Delayed graft function (DGF) after kidney transplantation is common and associated with worse graft outcomes. However, little is known about factors affecting graft survival post-DGF. We studied the association of cold ischemia time (CIT) and Kidney Donor Profile Index (KDPI) with the long-term outcomes of deceased brain-dead donor kidneys with and without DGF. Data from Finland (n = 2,637) and from the US Scientific Registry of Transplant Recipients (SRTR) registry (n = 61,405) was used. The association of KDPI and CIT with the graft survival of kidneys with or without DGF was studied using multivariable models. 849 (32%) kidneys had DGF in the Finnish cohort. DGF and KDPI were independent risk factors for graft loss, [HR 1.32 (95% CI 1.14-1.53), p < 0.001, and HR 1.01 per one point (95% CI 1.01-1.01), p < 0.001, respectively], but CIT was not, [HR 1.00 per CIT hour (95% CI 0.99-1.02), p = 0.84]. The association of DGF remained similar regardless of CIT and KDPI. The US cohort had similar results, but the association of DGF was stronger with higher KDPI. In conclusion, DGF and KDPI, but not CIT, are independently associated with graft survival. The association of DGF with worse graft survival is consistent across different CITs but stronger among marginal donors.

Peritoneal dialysis catheter removal at the time or after kidney transplantation: a systematic review and meta-analysis

PURPOSE

An increasing number of patients treated with peritoneal dialysis eventually undergo kidney transplantation. Owing to opposing reports, we aimed to find evidence about the best time for peritoneal dialysis catheter removal in transplant patients.

METHODS

We conducted a systematic review and random effects meta-analysis of non-randomized studies of intervention comparing patients with peritoneal dialysis catheters left in place or removed during kidney transplantation in regard to the need for dialysis and occurrence of catheter-related complications. We searched (last update on 8 December 2021) PubMed, Embase, Scopus, and Web of Science for eligible studies. ROBINS-I tool and funnel plot asymmetry analysis were used to assess the quality of included articles.

RESULTS

Eight observational studies were evaluated. Five of them, which involved 338 patients, were included in a meta-analysis. All were at moderate to serious risk of bias. The odds of needing dialysis are more than twice as high for patients with peritoneal dialysis catheters left in situ (pooled odds ratio, 2.21; 95% confidence interval [CI], 1.03 to 4.73; I2 = 0%). No statistically significant difference was noted when adult and pediatric subgroups were compared (Q = 0.13, P = .720). More individuals with catheters left in place required dialysis (pooled prevalence, 20.9%; 95% CI, 13.6 to 30.7%; I2 = 59% vs. 12.4%; 95% CI, 5.6 to 25.2%; I2 = 0%) and experienced catheter-related infections.

CONCLUSION

Available evidence is scarce. Unless new data from a randomized controlled trial are available, the dilemma of peritoneal dialysis catheter removal cannot be solved.

TRIAL REGISTRATION

PROSPERO Protocol ID: CRD42020207707.

Evaluation of severity of delayed graft function in kidney transplant recipients

BACKGROUND

The most common definition of delayed graft function (DGF) relies on dialysis during the first week post-transplant and does not consider DGF severity. The impact of DGF severity on long-term graft outcome remains controversial.

METHODS

We analyzed 627 deceased-donor kidney transplant recipients (KTR) transplanted 2005-2015 at our center for DGF-severity, associated risk factors and long-term consequences of DGF.

RESULTS

We found 349 (55.7%) KTR with DGF, which were classified into 4 groups according to DGF duration (0-1, 2-7, 8-14, >14 days) and were compared to KTR with no DGF. Increasing duration of DGF was associated with progressive worsening of 10-year death-censored graft survival (no DGF: 88.3% (95%CI: 82.4-94.2), 0-1 day: 81.3% (95%CI: 68.2-94.4), 2-7 days: 61.5% (95%CI: 43.1.1-79.9), 8-14 days: 66.6% (95%CI: 47.4-85.8), >14 days: 51.2% (95%CI: 33-69.4); p < 0.001). In kidneys with a Kidney Donor Profile Index (KDPI) ≥85% all DGF severity groups demonstrated reduced graft survival. However, in < 85%KDPI kidneys, only > 14 days DGF duration showed worse outcomes.

CONCLUSIONS

DGF had a duration-dependent effect on graft survival, which varied depending on KDPI. Of note, 0-1-day DGF showed comparable results to no DGF in the whole cohort.

Role of C5aR1 and C5L2 Receptors in Ischemia-Reperfusion Injury

The role of C5a receptors (C5aR1 and C5L2) in renal ischemia-reperfusion injury (IRI) is uncertain. We generated an in vitro model of hypoxia/reoxygenation with human proximal tubule epithelial cells to mimic some IRI events. C5aR1, membrane attack complex (MAC) and factor H (FH) deposits were evaluated with immunofluorescence. Quantitative polymerase chain reaction evaluated the expression of C5aR1, C5L2 genes as well as genes related to tubular injury, inflammation, and profibrotic pathways. Additionally, C5aR1 and C5L2 deposits were evaluated in kidney graft biopsies (KB) from transplant patients with delayed graft function (DGF, n = 12) and compared with a control group (n = 8). We observed higher immunofluorescence expression of C5aR1, MAC and FH as higher expression of genes related to tubular injury, inflammatory and profibrotic pathways and of C5aR1 in the hypoxic cells; whereas, C5L2 gene expression was unaffected by the hypoxic stimulus. Regarding KB, C5aR1 was detected in the apical and basal membrane of tubular epithelial cells, whereas C5L2 deposits were observed in endothelial cells of peritubular capillaries (PTC). DGF-KB showed more frequently diffuse C5aR1 staining and C5L2 compared to controls. In conclusion, C5aR1 expression is increased by hypoxia and IRI, both in vitro and in human biopsies with an acute injury. C5L2 expression in PTC could be related to endothelial cell damage during IRI.

A Role for Human Renal Tubular Epithelial Cells in Direct Allo-Recognition by CD4+ T-Cells and the Effect of Ischemia-Reperfusion

Direct allorecognition is the earliest and most potent immune response against a kidney allograft. Currently, it is thought that passenger donor professional antigen-presenting cells (APCs) are responsible. Further, many studies support that graft ischemia-reperfusion injury increases the probability of acute rejection. We evaluated the possible role of primary human proximal renal tubular epithelial cells (RPTECs) in direct allorecognition by CD4+ T-cells and the effect of anoxia-reoxygenation. In cell culture, we detected that RPTECs express all the required molecules for CD4+ T-cell activation (HLA-DR, CD80, and ICAM-1). Anoxia-reoxygenation decreased HLA-DR and CD80 but increased ICAM-1. Following this, RPTECs were co-cultured with alloreactive CD4+ T-cells. In T-cells, zeta chain phosphorylation and c-Myc increased, indicating activation of T-cell receptor and co-stimulation signal transduction pathways, respectively. T-cell proliferation assessed with bromodeoxyuridine assay and with the marker Ki-67 increased. Previous culture of RPTECs under anoxia raised all the above parameters in T-cells. FOXP3 remained unaffected in all cases, signifying that proliferating T-cells were not differentiated towards a regulatory phenotype. Our results support that direct allorecognition may be mediated by RPTECs even in the absence of donor-derived professional APCs. Also, ischemia-reperfusion injury of the graft may enhance the above capacity of RPTECs, increasing the possibility of acute rejection.