Renal transplantation in adults

Clinical Implications and Risk Factors for Erectile Dysfunction in Kidney Transplant: A Single-Center Assessment

BACKGROUND

Erectile dysfunction (ED) affects the great majority of people undergoing dialysis and also the majority of patients undergoing kidney transplantation. In this study, we investigated the degree of erectile dysfunction (ED), as well as its prevalence, contributory variables, and overall impact after renal transplant.

METHODS

Adult male kidney transplant patients were the subject of an observational, non-interventional study that was conducted at a single center. Age, time and type of dialysis before transplantation, comorbidities, factors associated with cardiovascular risk, data on sexual history, physical examination, and laboratory results were among the clinical data we examined. In addition to gathering clinical and demographic characteristics, the International Index of Erectile Function (IIEF) questionnaire was used to evaluate sexual function.

RESULTS

A total of 170 renal transplanted patients between 20 and 70 years old (mean age: 45.40±11.5) were included in this study. All of the patients had immunosuppressive treatment with a calcineurin inhibitor (cyclosporine or tacrolimus) and had a normal glomerular filtration rate (GFR). The prevalence of sexual dysfunction increased with age (42.6% of patients under 40, 47.4% of patients in the 40-60 age group, and 78.9% of patients over 60). Mild, moderate, and severe ED was noted in 33.5%, 20.6%, and 10.6% of cases, respectively, and 51 (30%) patients reported having a normal sexual function. While calcium channel blockers (122 cases) were the most commonly used antihypertensive medication and chronic glomerulosclerosis (55.3%) was the most common cause of chronic kidney disease (CKD) before transplantation, none of these variables appear to have affected the severity of erectile dysfunction. The only medications associated with sexual dysfunction were alpha-blockers and aspirin (75 mg) (p=0.026 and p=0.013, respectively).

CONCLUSIONS

Although kidney transplantation has positive impacts on the quality of life, erectile dysfunction is a frequent condition among patients with renal transplants, and it has an increased frequency with age. In our study, it has been observed that only a small percentage of the research group had a normal sexual function, although most of the patients were young, and that alpha-blockers and aspirin (75 mg) are associated with erectile dysfunction.

Reversed diastolic flow in a renal transplant due to ureteric obstruction from intraluminal blood clot

Reversal of arterial diastolic flow is commonly considered a sign of transplant renal vein thrombosis until proven otherwise, with the differential including acute rejection, acute tubular necrosis, and perirenal hematoma. We discuss a case of a patient who presented with decreased urine output on the second postoperative day following living unrelated kidney transplantation. Doppler ultrasound was performed and demonstrated reversal of diastolic flow in the transplant renal artery. Prompt surgical exploration revealed intraluminal blood clot obstructing the ureter. To our knowledge, this is the first reported case of reversed diastolic flow secondary to ureteral obstruction by an intraluminal blood clot.

Long-Term Redistribution of Peripheral Lymphocyte Subpopulations after Switching from Calcineurin to mTOR Inhibitors in Kidney Transplant Recipients

Classical immunosuppression based on steroids, calcineurin inhibitors, and mycophenolate results in several unwanted effects and unsatisfactory long-term outcomes in kidney transplantation (KT). New immunosuppressors search for fewer adverse events and increased graft survival but may have a distinct impact on graft function and immunological biomarkers according to their mechanism of action. This prospective study evaluates the immunological effect of tacrolimus to serine/threonine protein kinase mechanistic target of rapamycin inhibitors (mTORi) conversion in 29 KT recipients compared with 16 controls maintained on tacrolimus. We evaluated renal function, human leukocyte antigen (HLA) antibodies and peripheral blood lymphocyte subsets at inclusion and at 3, 12, and 24 months later. Twenty immunophenotyped healthy subjects served as reference. Renal function remained stable in both groups with no significant change in proteinuria. Two patients in the mTORi group developed HLA donor-specific antibodies and none in the control group (7% vs. 0%, p = 0.53). Both groups showed a progressive increase in regulatory T cells, more prominent in patients converted to mTORi within the first 18 months post-KT (p < 0.001). All patients showed a decrease in naïve B cells (p < 0.001), excepting those converted to mTORi without receiving steroids (p = 0.31). Transitional B cells significantly decreased in mTORi patients (p < 0.001), independently of concomitant steroid treatment. Finally, CD56^bright and CD94/NK group 2 member A receptor positive (NKG2A⁺) Natural Killer (NK) cell subsets increased in mTORi- compared to tacrolimus-treated patients (both p < 0.001). Patients switched to mTORi displayed a significant redistribution of peripheral blood lymphocyte subpopulations proposed to be associated with graft outcomes. The administration of steroids modified some of these changes.

Occurrence of Diabetic Nephropathy After Renal Transplantation Despite Intensive Glycemic Control: An Observational Cohort Study

OBJECTIVE

The kinetics and risk factors of diabetic nephropathy after kidney transplantation remain unclear. This study investigated the posttransplant occurrence of diabetic nephropathy and the contribution of posttransplant glycemic control.

RESEARCH DESIGN AND METHODS

We performed a single-center prospective cohort study of 953 renal allograft recipients and 3,458 protocol-specified renal allograft biopsy specimens up to 5 years after transplantation. The effects of pretransplant diabetes and glycemic control (glycated hemoglobin levels) on the posttransplant histology were studied.

RESULTS

Before transplantation, diabetes was present in 164 (17.2%) renal allograft recipients, primarily type 2 (n = 146 [89.0%]). Despite intensive glycemic control (glycated hemoglobin 7.00 ± 1.34% [53 ± 14.6 mmol/mol], 6.90 ± 1.22% [52 ± 13.3 mmol/mol], and 7.10 ± 1.13% [54 ± 12.4 mmol/mol], at 1, 2, and 5 years after transplantation), mesangial matrix expansion reached a cumulative incidence of 47.7% by 5 years in the pretransplant diabetes group versus 27.1% in patients without diabetes, corresponding to a hazard ratio of 1.55 (95% CI 1.07-2.26; P = 0.005). Mesangial matrix expansion was not specific for diabetic nephropathy and associated independently with increasing age. Pretransplant diabetes was associated with posttransplant proteinuria but not with estimated glomerular filtration rate, graft failure, or any other structural changes of the glomerular, vascular, or tubulointerstitial renal compartments. The occurrence of diabetic nephropathy was independent of posttransplant glycated hemoglobin levels.

CONCLUSIONS

Mesangial matrix expansion, an early indicator of diabetic nephropathy, can occur rapidly in patients with diabetes before transplantation, despite intensive glycemic control. Prevention of diabetic nephropathy requires more than pursuing low levels of glycated hemoglobin.

Use of single-dose perioperative antimicrobial therapy is acceptable in recipients of living-donor renal transplants in the rituximab era

OBJECTIVE

The aim of this study was to evaluate the efficacy of single-dose perioperative antimicrobial therapy as infection prophylaxis in recipients of living-donor renal transplants in the rituximab era.

PATIENTS AND METHODS

Between 2009 and 2017, 84 recipients underwent living-donor renal transplantation (LDRT) at Okayama University Hospital; 3 with vascular/urinary complications requiring additional surgery were excluded from this analysis. Data including recipient characteristics, antimicrobial prophylaxis and administration of rituximab were retrospectively examined for an association with perioperative infections. Prophylactic antimicrobial agents, selected according to the Results of preoperative urine cultures, were administered just before incision. Perioperative infections, which consisted of surgical site infections, remote infections, and urinary tract infections, were defined as a positive culture indicating required administration of additional antimicrobial agents.

RESULTS

Among the 81 recipients, prophylactic cefazolin, ampicillin/sulbactam, and others were administered to 66 (82%), 13 (16%), and 2 (3%) recipients, respectively. Twenty-one (26%) received single-dose antimicrobial prophylaxis, while 60 (74%) received multiple doses up to 7 days. Rituximab was used in 59 (72.8%) recipients. The incidence of urinary tract infection, surgical site infection and remote infection was 13 (16%), 1 (1%), and 0, respectively. Univariate analysis could not demonstrate any significant risk factors for postoperative urinary tract infections, including a single dose vs multiple doses of antimicrobial therapy (P = 0.069) and administration of rituximab (P = 0.717).

CONCLUSIONS

Our data suggest that the use of single-dose perioperative antimicrobial therapy is acceptable for prophylaxis of infections in patients undergoing LDRT, even in the rituximab era.

Repatriation of Patients to Referral Centers and Outcomes After Kidney Transplantation: A Single-center Analysis From the United Kingdom

Background

The aim of this study was to compare posttransplant outcomes of kidney allograft recipients between those followed up at transplant centers and those that were repatriated back to referral renal units.

Methods

We analyzed data for 1375 consecutive patients transplanted in a single center in the United Kingdom. Patients were stratified into 3 groups: (1) externally referred patients with repatriation back for external follow-up (repatriated, n = 463), (2) externally referred patients not repatriated and followed-up internally at transplant center (nonrepatriated, n = 365), and (3) internally referred patients within transplant center with continued internal transplant center follow-up (internal, n = 547). Patient and death-censored graft survival were compared between groups on both univariable and multivariable analyses.

Results

Baseline comparisons found that the nonrepatriated group had increased risk for prolonged length of stay and delayed graft function compared with repatriated patients. The nonrepatriated group had significantly shorter survival compared to the repatriated patients (90.2% vs 94.1% at 5 years, P = 0.013), which persisted after adjustment for confounders on multivariable analysis (hazard ratio, 1.86; 95% confidence interval, 1.06-3.28; P = 0.032). Death-censored graft survival was not found to differ significantly between the 3 groups (P = 0.192).

Conclusions

Our results provide reassurance regarding repatriation of care after kidney transplantation for the United Kingdom. Nonrepatriated patients are identified as a high-risk group for increased mortality, but further investigation is warranted to probe this heterogeneous group and validate in a non-United Kingdom cohort.