Cardiovascular complications after renal transplantation and their prevention

Only bioactive forms of PTH (n-oxPTH and Met18(ox)-PTH) inhibit synthesis of sclerostin - evidence from in vitro and human studies

Sclerostin (SOST) is produced by osteocytes and is known as a negative regulator of bone homeostasis. Parathyroid hormone (PTH) regulates calcium, phosphate as well as vitamin D metabolism, and is a strong inhibitor of SOST synthesis in vitro and in vivo. PTH has two methionine amino acids (positions 8 and 18) which can be oxidized. PTH oxidized at Met18 (Met18(ox)-PTH) continues to be bioactive, whereas PTH oxidized at Met8 (Met8(ox)-PTH) or PTH oxidized at Met8 and Met18 (Met8, Met18(di-ox)-PTH) has minor bioactivity. How non-oxidized PTH (n-oxPTH) and oxidized forms of PTH act on sclerostin synthesis is unknown. The effects of n-oxPTH and oxidized forms of PTH on SOST gene expression were evaluated in UMR106 osteoblast-like cells. Moreover, we analyzed the relationship of SOST with n-oxPTH and all forms of oxPTH in 516 stable kidney transplant recipients using an assay system that can distinguish in clinical samples between n-oxPTH and the sum of all oxidized PTH forms (Met8(ox)-PTH, Met18(ox)-PTH, and Met8, Met18(di-ox)-PTH). We found that both n-oxPTH and Met18(ox)-PTH at doses of 1, 3, 20, and 30 nmol/L significantly inhibit SOST gene expression in vitro, whereas Met8(ox)-PTH and Met8, Met18(di-ox)-PTH only have a weak inhibitory effect on SOST gene expression. In the clinical cohort, multivariate linear regression showed that only n-oxPTH, but not intact PTH (iPTH) nor oxPTH, is independently associated with circulating SOST after adjusting for known confounding factors. In conclusion, only bioactive PTH forms such as n-oxPTH and Met18(ox)-PTH, inhibit SOST synthesis.

A Multinational Cohort Study Examining Sex Differences in Excess Risk of Death With Graft Function After Kidney Transplant

BACKGROUND

Kidney transplant recipients show sex differences in excess overall mortality risk that vary by donor sex and recipient age. However, whether the excess risk of death with graft function (DWGF) differs by recipient sex is unknown.

METHODS

In this study, we combined data from 3 of the largest transplant registries worldwide (Scientific Registry of Transplant Recipient, Australia and New Zealand Dialysis and Transplant Registry, and Collaborative Transplant Study) using individual patient data meta-analysis to compare the excess risk of DWGF between male and female recipients of a first deceased donor kidney transplant (1988-2019), conditional on donor sex and recipient age.

RESULTS

Among 463 895 individuals examined, when the donor was male, female recipients aged 0 to 12 y experienced a higher excess risk of DWGF than male recipients (relative excess risk 1.68; 95% confidence interval, 1.24-2.29); there were no significant differences in other age intervals or at any age when the donor was female. There was no statistically significant between-cohort heterogeneity.

CONCLUSIONS

Given the lack of sex differences in the excess risk of DWGF (other than in prepubertal recipients of a male donor kidney) and the known greater excess overall mortality risk for female recipients compared with male recipients in the setting of a male donor, future study is required to characterize potential sex-specific causes of death after graft loss.

Post-Transplant Cardiovascular Disease in Kidney Transplant Recipients: Incidence, Risk Factors, and Outcomes in the Era of Modern Immunosuppression

Introduction: Post-transplant cardiovascular disease (PTCVD) poses a significant challenge in kidney transplantation, potentially impacting graft outcomes and patient survival. This retrospective study aimed to investigate the incidence, risk factors, and consequential impact of PTCVD in kidney transplant recipients (KTRs) devoid of pre-existing cardiovascular disease (CVD). Method: The cohort comprised 1114 KTRs, with 749 individuals included after excluding those with pre-existing CVD and early graft loss. PTCVD encompasses ischemic heart disease, myocardial infarction, arrhythmias, heart failure, stroke, peripheral vascular disease, and valvular heart disease. Competing risk regression analysis was performed to identify predictors of PTCVD, while Cox proportional hazards analysis assessed the impact of PTCVD on graft and recipient survival. Results: The cumulative incidence of PTCVD at 5, 10, and 20 years was 5.4%, 14.3%, and 22.5%, respectively. Competing risk regression identified increased age (sub-hazard ratio [SHR], 1.22; p = 0.036) per decade, duration of dialysis (SHR, 1.07; p = 0.048) per year on dialysis, and the slope of the estimated glomerular filtration rate (SHR, 1.08; p = 0.008) mL/min/year decline as independent predictors of higher-risk PTCVD. A higher baseline estimated glomerular filtration rate (eGFR) was protective (SHR, 0.98; p = 0.032). PTCVD was not significantly associated with death-censored graft loss (adjusted hazard ratio [aHR] 1.31; p = 0.48) but was correlated with higher all-cause graft loss (aHR, 1.71; p = 0.011) and recipient mortality (aHR, 1.97; p = 0.004). Conclusion: This study provides insights into PTCVD predictors. Although not directly associated with graft loss, PTCVD significantly correlates with heightened mortality in kidney transplant recipients, emphasizing the need for enhanced clinical management and surveillance strategies.

Assessment of hepatic fibrosis with non-invasive indices in subjects with diabetes before and after liver transplantation

Introduction

One of the most common complications of cirrhosis is diabetes, which prevalence is strictly related to severity of hepatopathy. Actually, there are no data on the persistence of post-transplant glucose abnormalities and on a potential impact of diabetes on development of fibrosis in the transplanted liver. To this aim, we evaluated liver fibrosis in cirrhotic subjects before and after being transplanted.

Methods

The study included 111 individuals who had liver transplantation. The assessment was performed before and two years after surgery to investigate a potential impact of the persistence of diabetes on developing de novo fibrosis in the transplanted liver. The degree of fibrosis was assessed using the Fibrosis Index Based on 4 Factors (FIB-4) and the Aspartate to Platelet Ratio Index (APRI).

Results

At pre-transplant evaluation, 63 out of 111 (56.8%) subjects were diabetic. Diabetic subjects had higher FIB-4 (Geometric mean, 95% confidence interval: 9.74, 8.32-11.41 vs 5.93, 4.71-7.46, P<0.001) and APRI (2.04, 1.69-2.47 vs 1.18, 0.90-1.55, P<0.001) compared to non-diabetic subjects. Two years after transplantation, 39 out of 111 (35.1%) subjects remained with diabetes and continued to show significantly higher FIB-4 (3.14, 2.57-3.82 vs 1.87, 1.55-2.27, P<0.001) and APRI (0.52, 0.39-0.69 vs 0.26, 0.21-0.32, P<0.001) compared to subjects without diabetes.

Discussion

Thus, persistence of diabetes after surgery is a possible risk factor for an evolution to fibrosis in the transplanted liver, potentially leading to worsened long-term outcomes in this population.

Increased Circulating Irisin Levels in Kidney Transplant Patients: Is There a Connection with Glycaemic Control?

Irisin is a myokine with potential effects on glucose metabolism and the development of diabetes in humans. We analysed irisin serum levels (ISL) in 47 patients without diabetes before and 1, 2, 3, 4 and 5 weeks after kidney transplantation (KTx). All measurements of irisin before KTx levels were lower than 25 ng/mL (median 8.4 ng/mL). We found an outstanding increase in ISL measured after KTx, reaching more than 1000 times in 44% of patients (HIL-high irisin level group). The increase appeared at the first measurement (one week after KTx). Factors connected to the large growth of ISL were, i.e., BMI > 30 (p = 0.04) and subsequent KTx-second and third (p < 0.001). The global mean blood glucose level during the first two weeks after KTx was significantly lower in the HIL group (p = 0.002), the same as the day-by-day analysed mean fasting and postprandial serum glucose in the first days after KTx. In 12 months of observation, diabetes requiring insulin therapy occurred in the HIL group at a rate of 19%, while in the rest of the patients, the rate was 27%, p = 0.526. Irisin levels increase significantly in some patients after kidney transplantation, accompanied by lower blood glucose levels in the early post-transplant period. Whether an increase in irisin levels results in better glycaemic control remains questionable and requires further research, as well as the relationship between irisin levels and the occurrence of PTDM.

Conversion from calcineurin inhibitors to belatacept-based immunosuppressive therapy skews terminal proliferation of non-classical monocytes and lowers lymphocyte counts

Belatacept, a modified form of CTLA-Ig that blocks CD28-mediated co-stimulation of T cells, is an immune-suppressant that can be used as an alternative to calcineurin inhibitors (CNIs). In kidney transplant recipients, belatacept has been associated with improved renal function and reduced cardiovascular toxicity. Monocytes as well as T-lymphocytes play causal roles in the pathophysiology of atherosclerotic disease. We hypothesized that the beneficial impact of the use of belatacept over CNIs on cardiovascular risk could be partly explained by the impact of belatacept therapy on these circulating leukocytes. Hence, we phenotyped circulating leukocytes in transplanted patients with a stable renal function that were randomized between either continuation of CNI or conversion to belatacept in two international studies in which we participated. In 41 patients, we found that belatacept-treated patients consistently showed lower numbers of B-lymphocytes, T-lymphocytes as well as CD14-negative monocytes (CD14NM), especially in non-diabetic patients. Our observation that this decrease was associated to plasma concentrations of TNFα is consistent with a model where CD14NM-production of TNFα is diminished by belatacept-treatment, due to effects on the antigen-presenting cell compartment.

Diabetic Kidney Disease in Post-Kidney Transplant Patients

Post-transplant diabetes mellitus (PTDM) is a common occurrence in post-kidney transplantation and is associated with greater mortality, allograft failure, and increased risk of infections. The primary goal in the management of PTDM is to achieve glycemic control to minimize the risk of complications while balancing the need for immunosuppression to maintain the health of the transplanted kidney. This review summarizes the effects of maintenance immunosuppression and therapeutic options among kidney transplant recipients. Patients with PTDM are at increased risk of diabetic kidney disease development; therefore, in this review, we focus on evidence supporting the use of novel antidiabetic agents and discuss their benefits and potential side effects in detail.

Systematic review and meta-analysis of the efficacy of exercise intervention in kidney transplant recipients

BACKGROUND AND OBJECTIVE

There is uncertainty about the beneficial effects of exercise intervention for kidney transplant recipients. The purpose of our meta-analysis is to estimate the efficacy of exercise intervention in kidney transplant recipients.

METHODS

A database search according to the PICOS framework was performed for all published randomized, double-blind, placebo-controlled trials (RCTs) about exercise intervention for kidney transplant recipients. The databases involved include PubMed, Embase, and Cochrane Library.

RESULTS

A total of 16 RCTs (involving 827 patients) in compliance with inclusion criteria were included in our study. The results demonstrated that adequate exercise intervention improved statistically in creatinine clearance [mean difference (MD) =  - 0.29, 95% confidence interval (CI) - 0.46 to - 0.11, p = 0.001], serum urea (MD = - 21.57, 95% CI - 35.84 to - 7.29, p = 0.003), VO2 peak (MD = 3.20, 95% CI 1.97-4.43, p < 0.00001), high-density lipoprotein-cholesterol (HDL-C) (MD = 0.21, 95% CI 0.04-0.37, p = 0.01), 60-s sit to stand test (60-STS) (MD = 14.47, 95% CI 8.89-20.04, p < 0.00001), 6-min walk distance (6-MWD) (MD = 91.87, 95% CI 38.34-145.39, p = 0.0008), and 6-min walk test (6-MWT) (MD = 44.08, 95% CI 20.30-67.87, p = 0.0003) of patients after kidney transplantation. No between-groups differences (p > 0.05) were observed for anthropometric characteristics, body composition, serum cytokine levels, and quality of life short form-36 questionnaire (SF-36).

CONCLUSIONS

In kidney transplant recipients, appropriate exercise intervention improved renal function, cardiopulmonary function, physical performance.

TRIAL REGISTRATION

The PROSPERO registration number is CRD42022357574.

Safety, accuracy, and prediction of prognosis in patients with end-stage chronic kidney disease undergoing dobutamine stress cardiac magnetic resonance imaging

Introduction

Advanced chronic kidney disease (CKD) is an independent risk factor for coronary artery disease (CAD). Due to its unique uremia-derived pathophysiology of atherosclerosis and the limitations of using potentially harmful contrast agents, the best non-invasive approach to assess CAD in these patients remains unclear. We sought to investigate the accuracy, safety, and prognosis of patients with severe CKD undergoing dobutamine stress cardiac magnetic resonance imaging (CMR).

Materials and methods

In this retrospective, single-center study, patients on dialysis or with a glomerular filtration rate of <15 ml/min/1.73 m2 who underwent dobutamine stress CMR were included. A rest and stress wall motion analysis was performed using dobutamine/atropine as stressor. The target heart rate was 85% of the maximum heart rate. Periprocedural adverse events and 1-year follow-up data were obtained.

Results

A total of 176 patients (127 men, 49 women) with a mean age of 60.9 ± 14.7 years were included, of which 156 patients were on permanent dialysis. Short-term symptoms such as angina or shortness of breath during stress CMR were frequent (22.1%), but major complications were rare (one patient with myocardial infarction, 0.6%). The 1-year event rate was high (16.4%) with a significant independent correlation to reduced ejection fraction at rest (p = 0.037) and failure to achieve the target heart rate (p = 0.029). The overall accuracy for predicting significant CAD was good (sensitivity of 71.4%, specificity of 98.4%) and excellent if the target heart rate was achieved (83.3%, 97.9%). A negative stress CMR was highly predictive for the absence of major adverse cardiac event or any coronary revascularization during the 1-year follow-up (negative predictive value of 95.0%).

Discussion

Dobutamine stress CMR is a safe and accurate diagnostic imaging technique in patients at advanced stages of chronic kidney disease. A reduced ejection fraction and the inability to reach the target heart rate are independent predictors of a poor outcome.

Dual Kidney Transplantation: Single-Center Experience

BACKGROUND

Dual and en bloc kidney transplantation are strategies used to mitigate the disparity between a reduced organ pool and an ever-increasing need for organ procurement. En bloc refers to the implantation of 2 kidneys from a pediatric donor, compensating for small renal mass, whereas dual expanded criteria donor (DECD) transplantation refers to older donors with grafts otherwise rejected for single transplant, including expanded. This study describes one center's experience with dual and en bloc transplantation.

METHODS

A retrospective cohort study of dual kidney transplants (en bloc and DECD) from 1990 through 2021. The analysis included demographic, clinical, and survival analysis.

RESULTS

Of 46 patients who underwent dual kidney transplantation, 17 (37 %) received en-bloc transplantation. The overall mean recipient age was 49.4 ± 13.9 years old, younger in the en-bloc subgroup (39.2 vs 59.8 years old, P < .01). The mean time on dialysis was 37 ± 25 months. Delayed graft function was present in 17.4 % and primary nonfunction in 6.4 %, all from the DECD group. The estimated glomerular filtration rates at 1 and 5 years were 76.7 ± 28.7 and 80.4 ± 24.8 mL/min/1.73 m2, lower in the DECD group (65.9 vs 88.7 mL/min/1.73 m2, P = 0.02). Eleven recipients lost their graft during the study period: 63.6% from death with a functioning graft, 27.3% due to chronic graft dysfunction (a mean of 76.3 months after transplantation), and 9.1% due to vascular complications. Subgroup comparison found no differences regarding cold ischemia time or length of hospitalization. Kaplan-Meier estimates, censored for death with a functioning graft, resulted in a mean graft survival of 21.3 ± 1.3 years, with survival rates of 93.5, 90.5, and 84.1% at 1, 5, and 10 years, respectively, without significant differences between subgroups.

CONCLUSIONS

Both DECD and en bloc strategies provide safe and effective options to further expand the use of otherwise rejected kidneys. Neither of the 2 techniques was superior to the other.

Overview of Renal Transplantation for Primary Care Physicians: Workup, Complications, and Management

Kidney transplantation remains the treatment of choice for eligible patients with end-stage kidney disease. The last few decades have seen an expansion in the transplant recipient pool with over 250,000 patients living with a kidney transplant today. Because of limited bandwidth for ongoing follow-up and management of chronic medical conditions, transplant centers are directing more and more patients back to their general nephrologists and primary care doctors for longitudinal care. As a result, it is becoming increasingly important for primary care physicians to have a nuanced understanding of medications, complications, and chronic medical problems unique to transplant recipients. This article reviews the role of the primary care office in helping streamline the pretransplant evaluation process and long-term posttransplant care.

Differences in Physical Activity Levels between Healthy and Transplanted Children: Who Needs More Tips?

BACKGROUND

Advances in the medical-surgical field have significantly increased the life expectancy of patients undergoing solid organ transplantation but this exposes patients to long-term complications due to chronic therapies and changes in lifestyle. It is known that children affected by pathology tend to be more sedentary and inactivity represents a further risk factor for the onset of non-communicable diseases. The aim of the present study was to compare the lifestyle of two groups of young patients: one group of healthy subjects (HG) and one group of kidney or liver transplant recipients (TG).

METHODS

Patients were asked to complete Physical Activity Questionnaire for Older Children (PAQ-C).

RESULTS

A total of 104 subjects were recruited (50.9% male, mean age 12.8 ± 3.16 years old). No significant differences were observed in the final score between groups when comparing subjects based on health condition (Healthy 2.69 ± 0.65 vs. Transplant Group 2.42 ± 0.88), the intensity of sports activities (Competitive 2.82 ± 0.59 vs. Not Competitive 2.53 ± 0.7) or type of transplant (Liver 2.51 ± 0.91 vs. Kidney 2.16 ± 0.75).

CONCLUSION

The results of this study showed a worrying reality: children are engaged in low levels of physical activity regardless of their health status and in general the level of activity does not reach the recommended values even in the absence of contraindications. So, it is necessary to encourage healthy children to practice more PA and to introduce PA prescriptions for transplanted children to prevent their health from deteriorating due to sedentariness.

Effects of Cinacalcet on Post-transplantation Hypercalcemia and Hyperparathyroidism in Adult Kidney Transplant Patients: A Single-Center Experience

OBJECTIVE

Secondary hyperparathyroidism may manifest as hypercalcemia in the post-transplant period. The classical treatment method is parathyroidectomy and the alternative is oral cinacalcet, a calcimimetic agent therapy. We retrospectively investigated the effect of cinacalcet therapy on kidney and patient survival in these patients.

MATERIALS AND METHODS

In our single-center, retrospective, observational study, files of 934 patients who underwent renal transplantation in our unit between 2008 and 2022 were reviewed. A total of 23 patients were started on cinacalcet for the treatment of hypercalcemia (calcium > 10.3 mg/dl) and parathyroid hormone (PTH) elevation (>65 pg/ml). Patients with calcium < 10.3 mg/dl and PTH > 700 pg/ml at any time in the follow-up after renal transplantation were included in the study. In addition, the demographic data of the patients, baseline creatine, calcium, phosphorus, and PTH levels at the time of hypercalcemia, parathyroid ultrasonography, parathyroid scintigraphy, creatinine, calcium, phosphorus, and PTH levels in the last controls, and survival status were evaluated.

RESULTS

 The mean age of 23 patients included in the study was 52.7 ± 11 years (minimum: 32; maximum: 66). Of the patients, 16 (69.6%) were male, and 15 (65.2%) were transplanted from a living donor. Parathyroid scintigraphic revealed adenoma in three (13%) patients, hyperplasia in five patients (21.7%), and no involvement in 15 patients (65.2%). Cinacalcet treatment was initiated at a median of 33 months (interquartile range (IQR) = 13-96) after the kidney transplant operation. There was no graft loss in the patients during the follow-up period. Twenty-two patients (95.7%) were alive, and one patient died. The calcium level of the patients decreased from 11.3 ± 0.64 mg/dl to 9.98 ± 0.78 mg/dl (p = 0.001) after cinacalcet treatment. Phosphorus values increased from 2.7 ± 0.65 mg/dl to 3.10 ± 0.65 mg/dl (p = 0.004). On the other hand, there was no significant difference in PTH levels between the initial and final controls (285 (IQR = 150-573) vs. 260 pg/ml (IQR = 175-411), p = 0.650). Also, creatinine levels were similar (1.2 ± 0.38 vs. 1.24 ± 0.48 mg/dl, p = 0.43). Despite cinacalcet treatment, calcium levels did not decrease in eight patients. Complications such as renal dysfunction and pathological fracture did not develop in these patients.

CONCLUSIONS

It seems that cinacalcet treatment is a suitable option for patients with hypercalcemia and/or hyperparathyroidism with low drug interactions and good biochemical control after renal transplantation.

Nonskeletal and skeletal effects of high doses versus low doses of vitamin D3 in renal transplant recipients: Results of the VITALE (VITamin D supplementation in renAL transplant recipients) study, a randomized clinical trial

Vitamin D sufficiency is associated with a reduced risk of fractures, diabetes mellitus, cardiovascular events, and cancers, which are frequent complications after renal transplantation. The VITALE (VITamin D supplementation in renAL transplant recipients) study is a multicenter double-blind randomized trial, including nondiabetic adult renal transplant recipients with serum 25-hydroxy vitamin D (25(OH) vitamin D) levels of <30 ng/mL, which is randomized 12 to 48 months after transplantation to receive high (100 000 IU) or low doses (12 000 IU) of cholecalciferol every 2 weeks for 2 months and then monthly for 22 months. The primary outcome was a composite endpoint, including diabetes mellitus, major cardiovascular events, cancer, and death. Of 536 inclusions (50.8 [13.7] years, 335 men), 269 and 267 inclusions were in the high-dose and low-dose groups, respectively. The serum 25(OH) vitamin D levels increased by 23 versus 6 ng/mL in the high-dose and low-dose groups, respectively (P < .0001). In the intent-to-treat analysis, 15% versus 16% of the patients in the high-dose and low-dose groups, respectively, experienced a first event of the composite endpoint (hazard ratio, 0.94 [0.60-1.48]; P = .78), whereas 1% and 4% of patients in the high-dose and low-dose groups, respectively, experienced an incident symptomatic fracture (odds ratio, 0.24 [0.07-0.86], P = .03). The incidence of adverse events was similar between the groups. After renal transplantation, high doses of cholecalciferol are safe but do not reduce extraskeletal complications (trial registration: ClinicalTrials.gov; identifier: NCT01431430).

Clinical outcomes of kidney recipients with COVID-19 (COVID-19 in kidney recipients)

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic has caused significant mortality since late 2019. Patients undergoing kidney transplantation (KT) are prone to COVID-19 due to immunosuppressive drug use and various comorbidities such as hypertension and diabetes.

METHODS

One hundred thirty-three KT recipients with COVID-19 were included in this retrospective cohort study. Hospital mortality was considered a primary outcome, while acute kidney injury (AKI) was considered a secondary outcome. Demographic information, maintenance immunosuppression, medical history, laboratory information, and echocardiographic and electrocardiography results of patients were recorded. Patients were also followed for 2 months post-discharge for post-COVID-19 symptoms, readmission, and transplant function.

RESULTS

Regarding the primary outcome of the 133 patients, 13 died and 120 survived. The deceased patients were significantly older (median age, 64 vs. 50.5 years; p = 0.04) and had a significantly higher median serum creatinine level (p = 0.002) and lower median glomerular filtration rate (p = 0.010) than patients who survived. The incidence of AKI was 47.3%, more common in deceased patients (p = 0.038) than in patients who survived. Troponin levels were significantly higher in deceased patients and those with AKI (p = 0.0004 and p = 0.039, respectively) than in patients who survived and those without AKI. A multivariable Cox regression analysis revealed that older age (adjusted hazard ratio, 1.13; 95% confidence interval, 1.01-1.27) and AKI (adjusted hazard ratio, 3.43; 95% confidence interval, 1.34-8.79) were associated with in-hospital mortality.

CONCLUSION

In conclusion, kidney recipients with COVID-19 had a higher mortality rate than the general population, with a higher prevalence in older individuals and those who experienced AKI during hospitalization than in patients who survived and those without AKI.

Characteristics of stroke after liver and kidney transplantation

Background

The mechanism and characteristics of a post-transplantation stroke may differ between liver (LT) and kidney transplantation (KT), as the associated comorbidities and peri-surgical conditions are different. Herein, we investigated the characteristics and etiologies of stroke occurring after LT and KT.

Methods

Consecutive patients who received LT or KT between January 2005 to December 2020 who were diagnosed with ischemic or hemorrhagic stroke after transplantation were enrolled. Ischemic strokes were further classified according to the etiologies. The characteristics of stroke, including in-hospital stroke, perioperative stroke, stroke etiology, and timing of stroke, were compared between the LT and KT groups.

Results

There were 105 (1.8%) and 58 (1.3%) post-transplantation stroke patients in 5,950 LT and 4,475 KT recipients, respectively. Diabetes, hypertension, and coronary arterial disease were less frequent in the LT than the KT group. In-hospital and perioperative strokes were more common in LT than in the KT group (LT, 57.9%; KT, 39.7%; p = 0.03, and LT, 43.9%; KT, 27.6%; p = 0.04, respectively). Hemorrhagic strokes were also more common in the LT group (LT, 25.2%; KT, 8.6%; p = 0.01). Analysis of ischemic stroke etiology did not reveal significant difference between the two groups; undetermined etiology was the most common, followed by small vessel occlusion and cardioembolism. The 3-month mortality was similar between the two groups (both LT and KT, 10.3%) and was independently associated with in-hospital stroke and elevated C-reactive protein.

Conclusions

In-hospital, perioperative, and hemorrhagic strokes were more common in the LT group than in the KT group. Ischemic stroke subtypes did not differ significantly between the two groups and undetermined etiology was the most common cause of ischemic stroke in both groups. High mortality after stroke was noted in transplantation patients and was associated with in-hospital stroke.

Management of early graft candidiasis in a kidney transplant recipient

Balancing adequate immunosuppression with the risk of infection after renal transplantation remains a challenge. The presence of comorbidities adds to the challenge. Although infrequent, invasive fungal infections result in high morbidity and mortality risk in renal transplant recipients. This can be attributed to the intense immunosuppression in the first 6 months after renal transplantation, minimal symptomatology and the high mortality associated with fungal infections.

Due to minimal available evidence, clinical judgement guides management of graft candidiasis. There is a need to develop evidence-based management guidelines for the treatment of fungal infections in renal transplants. Here, we report a case of early-onset candidiasis in a transplanted kidney and present the histological findings, multidisciplinary discussions and treatment given.

Combined Donor-Recipient Obesity and the Risk of Graft Loss After Kidney Transplantation

Background: As the prevalence of obesity increases globally, appreciating the effect of donor and recipient (DR) obesity on graft outcomes is of increasing importance.

Methods: In a cohort of adult, kidney transplant recipients (2000–2017) identified using the SRTR, we used Cox proportional hazards models to examine the association between DR obesity pairing (body mass index (BMI) &gt;30 kg/m2), and death-censored graft loss (DCGL) or all-cause graft loss, and logistic regression to examine risk of delayed graft function (DGF) and ≤30 days graft loss. We also explored the association of DR weight mismatch (&gt;30 kg, 10-30 kg (D&gt;R; D&lt;R) and &lt;10 kg (D = R)) with each outcome, stratifying by DR obesity pairing.

Results: Relative to non-obese DR, obese DR were highest risk for all outcomes (DCGL: HR 1.26, 95% CI 1.22–1.32; all-cause graft loss: HR 1.09, 95% CI 1.06–1.12; DGF: OR 1.98, 95% CI 1.89–2.08; early graft loss: OR 1.34, 95% CI 1.19–1.51). Donor obesity modified the risk of recipient obesity and DCGL [p = 0.001] and all-cause graft loss [p &lt; 0.001] but not DGF or early graft loss. The known association of DR weight mismatch with DCGL was attenuated when either the donor or recipient was obese.

Conclusion: DR obesity status impacts early and late post-transplant outcomes.

Arterial Stiffness as a Cardiovascular Risk Factor After Successful Kidney Transplantation in Diabetic and Nondiabetic Patients

BACKGROUND

It is known that kidney transplantation (KTx) decreases mortality rate and increases life expectancy about 10 years compared with dialysis, particularly in patients with diabetes. However, cardiovascular disease is still the most common cause of death after transplantation.

PURPOSE

The evaluation of the cardiovascular risk after successful KTx in diabetic and nondiabetic patients.

METHODS

We enrolled 344 patients after KTx (mean age 52.7 years, M -62.5%). The cohort was divided into 2 groups diabetes (+) and diabetes (-). Arterial stiffness parameters (brachial-ankle and carotid-femoral pulse wave velocity, pulse pressure, pulsatile stress was assessed by an automated oscillometric device. All body composition parameters were evaluated based on bioelectrical impedance analysis and laboratory parameters were obtained from medical files of the patients.

RESULTS

Arterial stiffness parameters were higher in the diabetes (+) compared with diabetes (-) group, significantly. Body mass index was significantly higher in the diabetes (+) group, as well as body fat mass and visceral fat area. In the diabetes (+) group compared with the diabetes (-) group, whole-body phase angle was lower (4.54 vs 4.90 P = .006). Visceral fat area and whole-body phase angle correlated significantly with arterial stiffness parameters.

CONCLUSIONS

The evaluation of arterial stiffness and phase angle is a useful method for identifying patients at high cardiovascular risk. Therefore, we suggest that patients with diabetes after successful KTx due to the baseline high cardiolovascular risk, should be regularly assessed to monitor changes in blood vessels, body composition and undergo dietary intervention.

The effect of the very low dosage diltiazem on tacrolimus exposure very early after kidney transplantation: a randomized controlled trial

The objective of this study was to assess the effect of the very low dosage of diltiazem on tacrolimus exposure during the first week post-kidney transplantation, among cytochrome P450 (CYP) 3A5 expressers who did not receive diltiazem (EXplb), CYP3A5 expressers who received the very low dose diltiazem (EXdtz), CYP3A5 nonexpressers who did not receive diltiazem (NEplb), and CYP3A5 nonexpressers who received the very low dose diltiazem (NEdtz). Forty kidney recipients who receive tacrolimus-based immunosuppressive regimen were randomly assigned, with stratification on the CYP3A5 genotypes, to receive either diltiazem 30 mg every 12 h or a matched placebo. The observed median dose-adjusted area under the 12-h curve of tacrolimus concentration (AUC/D) at day 7 post-transplantation was lowest in the EXplb group followed by EXdtz, NEplb, and NEdtz at 34.9, 43.6, 49.4, and 71.1 ng*h/mL per mg, respectively. A Kruskal–Wallis test showed a significant difference in the mean ranks of AUC/D among groups. Significant differences between EXplb and NEplb, and between EXplb and NEdtz were demonstrated, whereas no sufficient evidence of significant differences was detected between the other pairs. In conclusion, coadministration of diltiazem 30 mg twice daily may be advantageous for increasing tacrolimus exposure early after kidney transplantation among CYP3A5 expressers.

Risk factors for graft loss and death among kidney transplant recipients: A competing risk analysis

INTRODUCTION

Kidney transplantation is the best therapeutical option for CKD patients. Graft loss risk factors are usually estimated with the cox method. Competing risk analysis could be useful to determine the impact of different events affecting graft survival, the occurrence of an outcome of interest can be precluded by another. We aimed to determine the risk factors for graft loss in the presence of mortality as a competing event.

METHODS

A retrospective cohort of 1454 kidney transplant recipients who were transplanted between July 1, 2008, to May 31, 2019, in Colombiana de Trasplantes, were analyzed to determine risk factors of graft loss and mortality at 5 years post-transplantation. Kidney and patient survival probabilities were estimated by the competing risk analysis. The Fine and Gray method was used to fit a multivariable model for each outcome. Three variable selection methods were compared, and the bootstrapping technique was used for internal validation as split method for resample. The performance of the final model was assessed calculating the prediction error, brier score, c-index and calibration plot.

RESULTS

Graft loss occurred in 169 patients (11.6%) and death in 137 (9.4%). Cumulative incidence for graft loss and death was 15.8% and 13.8% respectively. In a multivariable analysis, we found that BKV nephropathy, serum creatinine and increased number of renal biopsies were significant risk factors for graft loss. On the other hand, recipient age, acute cellular rejection, CMV disease were risk factors for death, and recipients with living donor had better survival compared to deceased-donor transplant and coronary stent. The c-index were 0.6 and 0.72 for graft loss and death model respectively.

CONCLUSION

We developed two prediction models for graft loss and death 5 years post-transplantation by a unique transplant program in Colombia. Using a competing risk multivariable analysis, we were able to identify 3 significant risk factors for graft loss and 5 significant risk factors for death. This contributes to have a better understanding of risk factors for graft loss in a Latin-American population. The predictive performance of the models was mild.

Morning blood pressure surge in renal transplant recipients: Its relation to graft function and arterial stiffness

BACKGROUND

When the blood pressure rises before awakening in the morning, it is called as morning blood pressure pulse (MBPS). MBPS is considered to be an independent risk factor for cardiovascular disease. The aim of this study was to investigate the associations between MBPS, graft function, arterial stiffness and echocardiographic indicies in renal transpant recipients.

METHODS

Among 600 renal transplant recipients, 122 patients who had a history of hypertension and were taking at least one antihypertensive medication were enrolled in the study. Arterial stiffness was measured by carotid-femoral pulse wave velocity (PWv), and echocardiographic indicies were assessed. 24 hour ambulatory blood pressure was monitored for all patients. MBPS was calculated by substracting morning systolic blood pressure from minimal asleep systolic blood pressure.

RESULTS

Mean morning, day time and asleep systolic blood pressure values were 171.2± 23.9, 137.9± 18.1, and 131.7 ± 18.9 respectively. Non-dipper hypertention status was observed in 93 patients. Mean MBPS was 35.6 ± 19.5 mm Hg, mean PWv was 6.5 ± 2.0 m/sec. Patients with MBPS ≥ 35 mm Hg, had significantly lower eGFR and higher proteinuria, PWv. higher left atrium volume and LVMI. In regression analysis, day time systolic blood pressure, asleep systolic blood pressure, morning blood pressure surge, non-dipper status and left ventricular mass index were detected as the predictors of graft function.

CONCLUSIONS

Increased morning blood pressure surge is associated with graft dysfunction, increased arterial stiffness and LVMI that contributes to cardiovascular mortality and morbidity in renal transplant recipients. This article is protected by copyright. All rights reserved.

Feasibility and acceptability of high-intensity interval training and moderate-intensity continuous training in kidney transplant recipients: the PACE-KD study

Background

Kidney transplant recipients (KTRs) exhibit unique elevated inflammation, impaired immune function, and increased cardiovascular risk. Although exercise reduces cardiovascular risk, there is limited research on this population, particularly surrounding novel high-intensity interval training (HIIT). The purpose of this pilot study was to determine the feasibility and acceptability of HIIT in KTRs.

Methods

Twenty KTRs (male 14; eGFR 58±19 mL/min/1.73 m²; age 49±11 years) were randomised and completed one of three trials: HIIT A (4-, 2-, and 1-min intervals; 80–90% watts at V̇O_2peak), HIITB (4×4 min intervals; 80–90% V̇O_2peak) or MICT (~40 min; 50–60% V̇O_2peak) for 24 supervised sessions on a stationary bike (approx. 3x/week over 8 weeks) and followed up for 3 months. Feasibility was assessed by recruitment, retention, and intervention acceptability and adherence.

Results

Twenty participants completed the intervention, and 8 of whom achieved the required intensity based on power output (HIIT A, 0/6 [0%]; HIITB, 3/8 [38%]; MICT, 5/6 [83%]). Participants completed 92% of the 24 sessions with 105 cancelled and rescheduled sessions and an average of 10 weeks to complete the intervention. Pre-intervention versus post-intervention V̇O_2peak (mL/kg^-1/min^-1) was 24.28±4.91 versus 27.06±4.82 in HIITA, 24.65±7.67 versus 27.48±8.23 in HIIT B, and 29.33±9.04 versus 33.05±9.90 in MICT. No adverse events were reported.

Conclusions

This is the first study to report the feasibility of HIIT in KTRs. Although participants struggled to achieve the required intensity (power), this study highlights the potential that exercise has to reduce cardiovascular risk in KTRs. HIIT and MICT performed on a cycle, with some modification, could be considered safe and feasible in KTRs. Larger scale trials are required to assess the efficacy of HIIT in KTRs and in particular identify the most appropriate intensities, recovery periods, and session duration. Some flexibility in delivery, such as incorporating home-based sessions, may need to be considered to improve recruitment and retention.

Trial registration

ISRCTN, ISRCTN17122775. Registered on 30 January 2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-01067-3.

Heads, Bodies, Brains, and Selves: Personal Identity and the Ethics of Whole-Body Transplantation

Plans to attempt what has been called a head transplant, a body transplant, and a head-to-body transplant in human beings raise numerous ethical, social, and legal questions, including the circumstances, if any, under which it would be ethically permissible to attempt whole-body transplantation (WBT) in human beings, the possible effect of WBT on family relationships, and how families should shape WBT decisions. Our assessment of many of these questions depends partially on how we respond to sometimes centuries-old philosophical thought experiments about personal identity. As with so much in bioethics, it is impossible to escape, or at least inadvisable to try to bypass, the relevant foundational philosophical concerns.

Statin use and incident cardiovascular events in renal transplant recipients

BACKGROUND

Statins achieve potent LDL lowering in the general population leading to a significant cardiovascular (CV) risk reduction. In renal transplant recipients (RTR) statins are included in treatment guidelines, however, conclusive evidence of improved cardiovascular outcomes has not been uniformly provided and concerns have been raised about simultaneous use of statins and the immunosuppressant cyclosporine. This study aimed to elucidate the effect of statins on a compound CV endpoint, comprised of ischaemic CV events and CV mortality in RTR, with subgroup analysis focussing on cyclosporine users.

METHOD

622 included RTR (follow-up 5.4 years) were matched based on propensity scores and dichotomized by statin use. Survival analysis was conducted.

RESULTS

Cox regression showed that statin use was not significantly associated with the compound CV endpoint in a fully adjusted model (HR = 0.81, 95% CI = 0.53-1.24, P = .33). Subgroup analyses in RTR using cyclosporine revealed a strong positive association of statin use with the CV compound outcome in a fully adjusted model (HR = 6.60, 95% CI 1.75-24.9, P = .005). Furthermore, statin use was positively correlated with cyclosporine trough levels (correlation coefficient 0.11, P = .04).

CONCLUSION

In conclusion, statin use does not significantly decrease incident CV events in an overall RTR cohort, but is independently associated with CV-specific mortality and events in cyclosporine using RTR, possibly due to a bilateral pharmacological interaction.

Risk of post-transplant cardiovascular events in kidney transplant recipients with preexisting aortoiliac stenosis

Prediction of the risk of cardiovascular events (CVE's) is important to optimize outcomes after kidney transplantation. Aortoiliac stenosis is frequently observed during pre‐transplant screening. We hypothesized that these patients are at higher risk of post‐transplant CVE's due to the joint underlying atherosclerotic disease. Therefore, we aimed to assess whether aortoiliac stenosis was associated with post‐transplant CVE's. This retrospective, single‐center cohort study included adult kidney transplant recipients, transplanted between 2000 and 2016, with contrast‐enhanced imaging available. Aortoiliac stenosis was classified according to the Trans‐Atlantic Inter‐Society Consensus (TASC) II classification and was defined as significant in case of ≥50% lumen narrowing. The primary outcome was CVE‐free survival. Eighty‐nine of 367 patients had significant aortoiliac stenosis and were found to have worse CVE‐free survival (median CVE‐free survival: stenosis 4.5 years (95% confidence interval (CI) 2.8–6.2), controls 8.9 years (95% CI 6.8–11.0); log‐rank test P < .001). TASC II C and D lesions were independent risk factors for a post‐transplant CVE with a hazard ratio of 2.15 (95% CI 1.05–4.38) and 6.56 (95% CI 2.74–15.70), respectively. Thus, kidney transplant recipients with TASC II C and D aortoiliac stenosis require extensive cardiovascular risk management pre‐, peri,‐ and post‐transplantation.

Diabetes mellitus in dialysis and renal transplantation

Diabetes mellitus is the commonest cause of end-stage kidney failure worldwide and is a proven and significant risk factor for the development of cardiovascular disease. Renal impairment has a significant impact on the physiology of glucose homeostasis as it reduces tissue sensitivity to insulin and reduces insulin clearance. Renal replacement therapy itself affects glucose control: peritoneal dialysis may induce hyperglycaemia due to glucose-rich dialysate and haemodialysis often causes hypoglycaemia due to the relatively low concentration of glucose in the dialysate. Autonomic neuropathy which is common in chronic kidney disease (CKD) and diabetes increases the risk for asymptomatic hypoglycaemia. Pharmacological options for improving glycaemic control are limited due to alterations to drug metabolism. Impaired glucose tolerance and diabetes are also common in the post-kidney-transplant setting and increase the risk of graft failure and mortality. This review seeks to summarise the literature and tackle the intricacies of glycaemic management in patients with CKD who are either on maintenance haemodialysis or have received a kidney transplant. It outlines changes to glycaemic targets, monitoring of glycaemic control, the use of oral hypoglycaemic agents, the management of severe hyperglycaemia in dialysis and kidney transplantation patients.

Performance of the various serum creatinine-based GFR estimating equations in pediatric kidney transplant recipients, stratified by age and CKD staging

BACKGROUND

Numerous equations are used to estimate glomerular filtration rate (eGFR), based on serum creatinine (SCr), demographic and anthropometric data, none established in pediatric kidney transplant recipients. This study aimed to validate the available SCr-based eGFR equations in comparison with a measured (mGFR), stratified by chronic kidney disease (CKD) stage and age at the time of testing.

METHODS

One hundred twenty-seven pediatric kidney transplant recipients with 411 mGFR values (plasma clearance of iothalamate) were enrolled in this retrospective study. The bias, precision, and accuracy (percentage of estimates within 10% and 30% of mGFR) of five SCr eGFR equations (original Schwartz, CKiDSCr equation, Pottel, Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)) were assessed.

RESULTS

Height-independent Pottel equation performed well across all the categories of age and CKD staging. CKiDSCr equation performed well in CKD stages II-V. The CKiDSCr equation had a lower bias in children < 15 years of age, while MDRD and CKD-EPI equations had less bias in children > 15 years. Overall, both the Pottel and CKiDSCr equations had high accuracy (80%) and low bias (< 5 ml/min/1.73 m²). In contrast, the original Schwartz, MDRD, and CKD-EPI equations displayed high bias and low precision/accuracy.

CONCLUSIONS

Given their low bias and high accuracy across ages and CKD stages, the Pottel or the CKiDSCr equation is better to assess eGFR in pediatric kidney transplant recipients. The Pottel equation outperformed other eGFR equations in adolescents.

An overview of the efficacy and safety of everolimus in adult solid organ transplant recipients

As the risk of graft loss due to acute rejection has declined, the goal of post-transplant management has switched to long-term preservation of organ function. Minimizing calcineurin inhibitor (CNI)-related nephrotoxicity is a key component of this objective. Everolimus is a mammalian target of rapamycin inhibitor/proliferation-signal inhibitor with potent immunosuppressive and anti-proliferative effects. It has been widely investigated in large randomized clinical studies that have shown it to have similar anti-rejection efficacy compared with standard-of-care regimens across organ transplant indications. With demonstrated potential to facilitate the reduction of CNI therapy and preserve renal function, everolimus is an alternative to the current standard-of-care CNI-based regimens used in de novo and maintenance solid organ transplantation recipients. Here, we provide an overview of the evidence from the everolimus clinical study program across kidney, liver, heart, and lung transplants, as well as other key data associated with its use in CNI reduction strategies in adult transplant recipients.

A Pilot Study of the Safety and Efficacy of Alkali Therapy on Vascular Function in Kidney Transplant Recipients

Introduction

Metabolic acidosis is associated with cardiovascular events, graft function, and mortality in kidney transplant recipients (KTRs). We examined the effect of alkali therapy on vascular endothelial function in KTRs.

Methods

We performed an 18-week, randomized, double-blind, placebo-controlled crossover pilot study examining the effect of sodium bicarbonate therapy versus placebo on vascular function in 20 adult KTRs at least 1 year from transplant with an estimated glomerular filtration rate (eGFR) ≥45 ml/min per 1.73 m² and a serum bicarbonate level of 20 to 26 mEq/L. Each treatment period was 8 weeks in duration with a 2-week washout period between treatments. The primary outcome was change in brachial artery flow-mediated dilation (FMD) between sodium bicarbonate treatment and placebo.

Results

Twenty patients completed the study and were included in the primary analysis. The mean (SD) baseline eGFR of participants was 75 (22) ml/min per 1.73 m², respectively. Serum bicarbonate levels did not increase significantly with treatment (0.3 [1.5] mEq/L, P = 0.37). Sodium bicarbonate therapy was not associated with worsening blood pressure, weight gain, or hypokalemia. There was no significant increase in FMD after 8 weeks of sodium bicarbonate therapy compared to placebo (mean change in FMD 2.2%, 95% CI -0.1 to 4.6, P = 0.06). There were no significant changes in high-sensitivity C-reactive protein, interleukin-6, eGFR, or urinary albumin-to-creatinine ratio during treatment. Urinary ammonium excretion decreased by 9 mmol/d (P=0.003), with sodium bicarbonate.

Conclusions

Sodium bicarbonate therapy is safe and feasible in KTRs, and our results strengthen the need for a larger randomized controlled trial.

Proteoglycan binding as proatherogenic function metric of apoB-containing lipoproteins and chronic kidney graft failure

Lipoprotein-proteoglycan binding is an early key event in atherosclerotic lesion formation and thus conceivably could play a major role in vasculopathy-driven chronic graft failure and cardiovascular mortality in renal transplant recipients. The present study investigated whether lipoprotein-proteoglycan binding susceptibility (LPBS) of apoB-containing lipoproteins and levels of the classical atherosclerosis biomarker LDL-C were associated with cardiovascular mortality (n = 130) and graft failure (n = 73) in 589 renal transplant recipients who were followed up from at least 1 year after transplantation for 9.5 years. At baseline, LPBS was significantly higher in patients who subsequently developed graft failure than in those with a surviving graft (1.68 ± 0.93 vs. 1.46 ± 0.49 nmol/mmol, P = 0.001). Cox regression analysis showed an association between LPBS and chronic graft failure in an age- and sex-adjusted model (hazard ratio: 1.45; 95% CI, 1.14–1.85; P = 0.002), but no association was observed with cardiovascular mortality. LDL-C levels were not associated with graft failure or cardiovascular mortality. This study shows that measurement of cholesterol retention outperformed the traditionally used quantitative parameter of LDL-C levels in predicting graft failure, suggesting a higher relevance of proatherogenic function than the quantity of apoB-containing lipoproteins in chronic kidney graft failure.

C-terminal and intact FGF23 in kidney transplant recipients and their associations with overall graft survival

Background

Increased fibroblast growth factor 23 (FGF23) is a risk factor for mortality, cardiovascular disease, and progression of chronic kidney disease. Limited data exist comparing the association of either c-terminal FGF23 (cFGF23) or intact FGF23 (iFGF23) in kidney transplant recipients (KTRs) with overall (all-cause) graft loss.

Methods

We conducted a prospective observational cohort study in 562 stable kidney transplant recipients. Patients were followed for graft loss and all-cause mortality for a median follow-up of 48 months.

Results

During a median follow-up of 48 months, 94 patients had overall graft loss (primary graft loss or death with functioning graft). Both cFGF23 and iFGF23 concentrations were significantly higher in patients with overall graft loss than those without (24.59 [11.43–87.82] versus 10.67 [5.99–22.73] pg/ml; p < 0.0001 and 45.24 [18.63–159.00] versus 29.04 [15.23–60.65] pg/ml; p = 0.002 for cFGF23 and iFGF23, respectively). Time-dependent ROC analysis showed that cFGF23 concentrations had a better discriminatory ability than iFGF23 concentrations in predicting overall (all-cause) graft loss. Cox regression analyses adjusted for risk factors showed that cFGF23 (HR for one unit increase of log transformed cFGF23: 1.35; 95% CI, 1.01–1.79; p = 0.043) but not iFGF23 (HR for one unit increase of log transformed iFGF23: 0.97; 95% CI, 0.75–1.25; p = 0.794) was associated with the overall graft loss.

Conclusion

Elevated cFGF23 concentrations at baseline are independently associated with an increased risk of overall graft loss. iFGF23 measurements were not independently associated with overall graft loss. The cFGF23 ELISA might detect bioactive FGF23 fragments that are not detected by the iFGF23 ELISA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02329-7.

Blood Pressure Treatment in Kidney Transplant Recipients-Can We Improve?

Hypertension in kidney transplant (KTx) recipients is common, affecting both patient and graft survival. Annual data from the Norwegian Renal Registry reveal that <50% of adult (>18 y) KTx recipients reach target blood pressure (BP) ≤130/80 mm Hg. The aim of this study was to identify the determinants of failure to achieve BP control.

mTOR inhibition improves mitochondria function/biogenesis and delays cardiovascular aging in kidney transplant recipients with chronic graft dysfunction

CVD remains the major cause of mortality with graft functioning in Kidney transplant recipients (KTRs), with an estimated risk of CV events about 50-fold higher than in the general population. Many strategies have been considered to reduce the CV risk such as the use of mTOR inhibitors. We evaluate whether chronic mTOR inhibition might influence CV aging in KTRs studying the molecular mechanisms involved in this effect. We retrospectively analyzed 210 KTRs with stable graft function on therapy with CNI and mycophenolic acid (Group A, 105 pts.), or with CNI and mTORi (Everolimus, Group B, 105 pts.). The presence of mTOR inhibitor in immunosuppressive therapy was associated to increase serum levels of Klotho with concomitant reduction in FGF-23, with a significant decrease in left ventricular mass. In addition, KTRs with mTORi improved mitochondrial function/biogenesis in PBMC with more efficient oxidative phosphorylation, antioxidant capacity and glutathione peroxidase activity. Finally, group B KTRs presented reduced levels of inflammaging markers such as reduced serum pentraxin-3 and p21ink expression in PBMC. In conclusion, we demonstrated that mTOR inhibition in immunosuppressive protocols prevents the occurrence and signs of CV aging in KTRs.

Belatacept in renal transplantation in comparison to tacrolimus and molecular understanding of resistance pattern: Meta-analysis and systematic review

BACKGROUND

The T-cell costimulation blocking agent belatacept has been identified as a possible substitute for calcineurin inhibitors, however, no consensus has been established against its use over the standard care agent Tacrolimus.

AIM

To evaluate the effectiveness of belatacept based maintenance immuno-suppressive regimens in comparison to tacrolimus in renal transplantion.

METHODS

We did extensive search of all the available literature comparing the role of belatacept to tacrolimus in renal transplant recipients by searching the PubMed, Embase, Cochrane, Crossref, Scopus, clinical trials registry on October 5, 2020.

RESULTS

The literature search identified four randomized controlled trials (n = 173 participants) comparing belatacept with tacrolimus. There was no significant difference in estimated renal function at 12 mo [mean difference 4.12 mL/min/1.73 m², confidence interval (CI): -2.18 to 10.42, P = 0.20]. Further, belatacept group was associated with significant increase in biopsy proven acute rejection [relative risk (RR) = 3.27, CI: 0.88 to 12.11, P = 0.08] and worse 12 mo allograft survival (RR = 4.51, CI: 1.23 to 16.58, P = 0.02). However, incidence of new onset diabetes mellitus was lower with belatacept at 12 mo (RR = 0.26, CI: 0.07 to 0.99, P = 0.05).

CONCLUSION

The evidence reviewed in this meta-analysis suggested that belatacept-based maintenance immunosuppression regimens were associated with an increased risk allograft loss in renal transplant recipients with equivalent renal functioning against standard tacrolimus; however, observed significantly reduced new onset diabetes mellitus after transplantation incidence and lower serum low density lipid profile levels in belatacept group. In addition, the adaptation of belatacept in renal transplantation has been forestalled by increased rates of rejection and resistance owing to development of various effector memory T cells through, parallel differentiation and immunological plasticity.

Metabolic Consequences of Solid Organ Transplantation

Metabolic complications affect over 50% of solid organ transplant recipients. These include posttransplant diabetes, nonalcoholic fatty liver disease, dyslipidemia, and obesity. Preexisting metabolic disease is further exacerbated with immunosuppression and posttransplant weight gain. Patients transition from a state of cachexia induced by end-organ disease to a pro-anabolic state after transplant due to weight gain, sedentary lifestyle, and suboptimal dietary habits in the setting of immunosuppression. Specific immunosuppressants have different metabolic effects, although all the foundation/maintenance immunosuppressants (calcineurin inhibitors, mTOR inhibitors) increase the risk of metabolic disease. In this comprehensive review, we summarize the emerging knowledge of the molecular pathogenesis of these different metabolic complications, and the potential genetic contribution (recipient +/- donor) to these conditions. These metabolic complications impact both graft and patient survival, particularly increasing the risk of cardiovascular and cancer-associated mortality. The current evidence for prevention and therapeutic management of posttransplant metabolic conditions is provided while highlighting gaps for future avenues in translational research.

COVID-19 severity in kidney transplant recipients is similar to nontransplant patients with similar comorbidities

Higher rates of severe COVID-19 have been reported in kidney transplant recipients (KTRs) compared to nontransplant patients. We aimed to determine if poorer outcomes were specifically related to chronic immunosuppression or underlying comorbidities. We used a 1:1 propensity score-matching method to compare survival and severe disease-free survival (defined as death and/or need for intensive care unit [ICU]) incidence in hospitalized KTRs and nontransplant control patients between February 26 and May 22, 2020. Patients were matched for risk factors of severe COVID-19: age, sex, body mass index, diabetes mellitus, preexisting cardiopathy, chronic lung disease, and basal renal function. We included 100 KTRs (median age [interquartile range (IQR)]) 64.7 years (55.3-73.1) in three French transplant centers. After a median follow-up of 13 days (7-30), transfer to ICU was required for 34 patients (34%) and death occurred in 26 patients (26%). Overall, 43 patients (43%) developed a severe disease during a median follow-up of 8.5 days (2-14). Propensity score matching to a large French cohort of 2017 patients hospitalized in 24 centers, revealed that survival was similar between KTRs and matched nontransplant patients with respective 30-day survival of 62.9% and 71% (p = .38) and severe disease-free 30-day survival of 50.6% and 47.5% (p = .91). These findings suggest that severity of COVID-19 in KTRs is related to their associated comorbidities and not to chronic immunosuppression.

Safety and effectiveness of everolimus in maintenance kidney transplant patients in the real-world setting: results from a 2-year post-marketing surveillance study in Japan

Background

Data on real-world use of everolimus (EVR) in Japanese maintenance kidney transplant (KTx) patients are limited. This post-marketing surveillance study was conducted to assess the safety and effectiveness of EVR, and identify factors affecting renal impairment.

Methods

Adult maintenance KTx patients were enrolled within 14 days of initiating EVR. Patient medical data were collected using electronic data capture case report forms at 6 months, 1, and 2 years after initiating EVR, or at discontinuation.

Results

All patients receiving EVR in Japan during the surveillance period were enrolled (N = 263). Mean time from transplantation to EVR initiation was 75.7 months. Decreased renal function (31.56%) was the primary reason for initiating EVR. In combination with EVR, the mean daily dose of tacrolimus and cyclosporine could be reduced to ~ 79 and ~ 64%, by 2 years, respectively. Incidences of serious adverse events and adverse drug reactions were 15.97 and 49.43%, respectively. Two-year graft survival rate was 95.82% and low in patients with baseline estimated glomerular filtration rate (eGFR; modification of diet in renal disease) < 30 mL/min/1.73 m² (69.57%; P < 0.0001) and urinary protein/creatinine ratio (UPCR) ≥ 0.55 g/gCr (84.21%; P = 0.0206). Throughout the survey, mean eGFR values were stable (> 55 mL/min/1.73 m²). Renal impairment was influenced by patient and donor age, eGFR, and UPCR at baseline.

Conclusions

No new safety concerns for the use of EVR in adult maintenance KTx patients were identified. Early EVR initiation may be considered in these patients before renal function deterioration occurs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10157-021-02024-9.

Impact of cardiovascular risk stratification strategies in kidney transplantation over time

BACKGROUND

Kidney transplant recipients exhibit a dramatically increased cardiovascular (CV) risk. In 2007, Austrian centres implemented a consensus of comprehensive CV screening programme prior to kidney transplantation (KT). The consensus placed a particular emphasis on screening for coronary artery disease (CAD) with cardiac computed tomography (CT) or coronary angiography (CAG) in patients with diabetes mellitus, known CAD or those having multiple conventional CV risk factors. Here, we investigate if this affected risk stratification and post-transplant CV outcomes.

METHODS

In a retrospective chart review, we evaluated 551 KTs performed from 2003 to 2015 in our centre. Patients were categorized into three groups: KT before (2003-07), directly after (2008-11) and 5 years after (2012-15) implementation of the consensus. We analysed clinical characteristics, the rate of cardiac CTs and CAGs prior to KT as well as major adverse cardiac events (MACEs) during a 2-year follow-up after KT.

RESULTS

The three study groups showed a homogeneous distribution of comorbidities and age. Significantly more cardiac CTs (13.6% versus 10.2% versus 44.8%; P = 0.002) and CAGs (39.6% versus 43.9% versus 56.2%; P = 0.003) were performed after the consensus. Coronary interventions were performed during 42 out of 260 CAGs (16.2%), the cumulative 2-year MACE incidence was 8.7%. Regarding MACE occurrence, no significant difference between the three groups was found.

CONCLUSION

CV risk stratification has become more rigorous and invasive after the implementation of the consensus; however, this was not associated with an improvement in CV outcome.

Physical activity and risk of cardiovascular events and all-cause mortality among kidney transplant recipients

BACKGROUND

Insufficient physical activity (PA) may increase the risk of all-cause mortality and cardiovascular disease (CVD) morbidity and mortality among kidney transplant recipients (KTRs), but limited research is available. We examine the relationship between PA and the development of CVD events, CVD death and all-cause mortality among KTRs.

METHODS

A total of 3050 KTRs enrolled in an international homocysteine-lowering randomized controlled trial were examined (38% female; mean age 51.8 ± 9.4 years; 75% white; 20% with prevalent CVD). PA was measured at baseline using a modified Yale Physical Activity Survey, divided into tertiles (T1, T2 and T3) from lowest to highest PA. Kaplan-Meier survival curves were used to graph the risk of events; Cox proportional hazards regression models examined the association of baseline PA levels with CVD events (e.g. stroke, myocardial infarction), CVD mortality and all-cause mortality over time.

RESULTS

Participants were followed up to 2500 days (mean 3.7 ± 1.6 years). The cohort experienced 426 CVD events and 357 deaths. Fully adjusted models revealed that, compared to the lowest tertile of PA, the highest tertile experienced a significantly lower risk of CVD events {hazard ratio [HR] 0.76 [95% confidence interval (CI) 0.59-0.98]}, CVD mortality [HR 0.58 (95% CI 0.35-0.96)] and all-cause mortality [HR 0.76 (95% CI 0.59-0.98)]. Results were similar in unadjusted models.

CONCLUSIONS

PA was associated with a reduced risk of CVD events and all-cause mortality among KTRs. These observed associations in a large, international sample, even when controlling for traditional CVD risk factors, indicate the potential importance of PA in reducing CVD and death among KTRs.

Antihypertensive Treatment in Kidney Transplant Recipients-A Current Single Center Experience

Arterial hypertension affects the survival of the kidney graft and the cardiovascular morbidity and mortality of the recipient after kidney transplantation (KTx). Thus, antihypertensive treatment is necessary for a vast majority of these patients. Long-term data on antihypertensive drugs and their effects on allograft function after KTx is still limited, and further investigation is required. We retrospectively analyzed a cohort of 854 recipients who received a kidney transplant at our transplant center between 2007 and 2015 with regard to antihypertensive treatment and its influence on graft function and survival. 1-y after KTx, 95.3% patients were treated with antihypertensive therapy. Of these, 38.6% received mono- or dual-drug therapy, 38.0% received three to four drugs and 8.1% were on a regimen of ≥5 drugs. Beta-blockers were the most frequently used antihypertensive agents (68.1%). Neither the use of angiotensin-converting enzyme inhibitor/angiotensin receptor blockers (51.9%) and calcium channel blockers (51.5%), nor the use the use of loop diuretics (38.7%) affected allograft survival. Arterial hypertension and the number of antihypertensive agents were associated with unfavorable allograft outcomes (each p < 0.001). In addition to the well-known risk factors of cold ischemic time and acute rejection episodes, the number of antihypertensive drugs after one year, which reflects the severity of hypertension, is a strong predictor of unfavorable allograft survival.

Care of the Renal Transplant Patient

Renal transplant has become a mainstay of treatment of patients with chronic renal failure. With improving survival outcomes, primary care physicians should be informed of the nuances that come with the ongoing care of this population and feel empowered to take part in the multidisciplinary care of these patients. This article provides an overview of the renal transplant process from initial evaluation through surgery and then focuses on long-term issues that renal transplant patients face in the primary care setting.

Diabetogenic Effects of Immunosuppression: An Integrative Analysis

BACKGROUND

Posttransplant diabetes mellitus (PTDM) affects up to 50% of solid organ transplant recipients and compromises long-term outcomes. The goal of this study was to investigate how immunosuppressants affect gene expression in a manner that increases diabetes risk, by performing integrative analysis on publicly available, high-throughput gene expression data.

METHODS

All high-throughput gene expression datasets of solid organ transplant recipients were retrieved from the Gene Expression Omnibus. Significantly dysregulated genes and pathways were determined, and those in common with type 2 diabetes were identified. THP-1 and HepG2 cells were exposed in vitro to tacrolimus, and validation of genes involved in insulin signaling and glucose metabolism was performed using specific arrays. These cells were then treated with the hypoglycemic agents, metformin, and insulin to assess for appropriate reversion of specific diabetogenic genes.

RESULTS

Insulin signaling and secretion were the most commonly dysregulated pathways that overlapped with diabetes in transplant recipients. KRAS, GRB2, PCK2, BCL2L1, INSL3, DOK3, and PTPN1 were among the most significantly upregulated genes in both immunosuppression and diabetes subsets and were appropriately reverted by metformin as confirmed in vitro.

CONCLUSIONS

We discovered that the significantly dysregulated genes in the context of immunosuppression are implicated in insulin signaling and insulin secretion, as a manifestation of pancreatic β-cell function. In vitro validation confirmed key diabetes-related genes in the context of immunosuppression. Further analysis and in vitro validation revealed that metformin optimally reverts diabetogenic genes dysregulated in the context of immunosuppression. The optimal therapeutic management of posttransplant diabetes mellitus needs to be further investigated, taking into account the mechanistic impact of immunosuppressants.

Sclerostin is an independent risk factor for all-cause mortality in kidney transplant recipients

Background

Sclerostin is a hormone contributing to the bone-vascular wall cross talk and has been implicated in cardiovascular events and mortality in patients with chronic kidney disease (CKD). We analyzed the relationship between sclerostin and mortality in renal transplant recipients.

Methods

600 stable renal transplant recipients (367men, 233 women) were followed for all-cause mortality for 3 years. Blood and urine samples for analysis and clinical data were collected at study entry. We performed Kaplan–Meier survival analysis and Cox regression models considering confounding factors such as age, eGFR, cold ischemia time, HbA1c, phosphate, calcium, and albumin. Optimal cut-off values for the Cox regression model were calculated based on ROC analysis.

Results

Sixty-five patients died during the observation period. Nonsurvivors (n = 65; sclerostin 57.31 ± 30.28 pmol/L) had higher plasma sclerostin levels than survivors (n = 535; sclerostin 47.52 ± 24.87 pmol/L) (p = 0.0036). Kaplan–Meier curve showed that baseline plasma sclerostin concentrations were associated with all-cause mortality in stable kidney transplant recipients (p = 0.0085, log-rank test). After multiple Cox regression analysis, plasma levels of sclerostin remained an independent predictor of all-cause mortality (hazard ratio, 1.011; 95% CI 1.002–1.020; p = 0.0137).

Conclusions

Baseline plasma sclerostin is an independent risk factor for all-cause mortality in patients after kidney transplantation.

Electronic supplementary material

The online version of this article (10.1007/s10157-020-01956-y) contains supplementary material, which is available to authorized users.

Myocardial ischemia by radionuclide imaging and long-term outcomes after kidney transplantation

PURPOSE

We examined the incidence of myocardial ischemia (MI) in kidney transplant recipients (KTR) using myocardial perfusion imaging (MPI), and its association with long-term outcomes after transplantation.

METHODS

A retrospective observational study was conducted of asymptomatic KTRs who underwent post-transplant MPI screening for MI, as defined by moderate to severe myocardial perfusion defects, post-stress myocardial stunning or balanced ischemia. A composite outcome of all-cause mortality, graft loss, and major adverse cardiovascular events (MACE) was examined over minimum 5 years.

RESULTS

We studied 135 KTRs who underwent 226 MPIs, with follow-up duration of 10 (7-13) years. 110 (81%) patients had normal MPIs, 11 (8%) had mild perfusion defects, and 14 (10%) had MI. Correspondingly, composite outcome developed in 6%, 27%, and 43% (p = 0.04), and MACE occurred in 7%, 0%, and 21% (p = 0.11), of the respective subgroups. Twenty-six patients developed the composite outcome after 5 (3-7) years post-transplantation, including 11 patients with MACE. On multivariate analysis, MI, higher low-density lipoprotein levels, and proteinuria > 0.3 g/day independently predicted the composite outcome; only MI predicted MACE (all p < 0.05). Ninety-one patients had two serial MPIs, which increased the positive predictive value for MACE from 17 to 25%. Absence of MI had negative predictive value of 83% for MACE and 93% for the composite outcome.

CONCLUSION

MI that is detected early post-kidney transplantation predicts long-term mortality, graft loss, and MACE in KTRs, with excellent negative but poor positive predictive values.

Long-term Assessment of NSAID Prescriptions and Potential Nephrotoxicity Risk in Adult Kidney Transplant Recipients

BACKGROUND

Nonsteroidal anti-inflammatory drug (NSAID) use is recommended to be avoided in kidney transplantation, with a paucity of studies assessing their safety within this population. This study aims to use a large cohort of Veterans Affairs (VA) kidney transplantation recipients to assess the risk of acute kidney injury (AKI) with NSAID use.

METHODS

This is a 10-year longitudinal cohort study of adult kidney transplant recipients retrospectively followed in the VA system from 2001 to 2010 that assessed for risk of AKI with NSAID prescriptions. NSAID prescriptions, patient characteristics, and estimated glomerular filtration rates were abstracted from the VA comprehensive electronic health record. NSAID exposure was assessed by duration, dosage, and type. AKI events were defined by ≥50% decrease in estimated glomerular filtration rate. Risk was estimated using longitudinal multivariable generalized logistic regression model.

RESULTS

About 5100 patients were included with a total of 29 980 years of follow-up; 671 NSAID prescriptions in 273 (5.4%) patients (2.24 per 100 patient-y) with 472 (70%) high dose were identified. High-dose NSAID prescriptions were associated with 2.83 (95% confidence interval [CI], 1.55-5.19; P < 0.001) higher odds of AKI events within a given year; low dose was not associated with AKI (odds ratio, 1.93; 95 % CI, 0.95-6.02; P = 0.256). One 7-day NSAID course was associated with 5% higher odds of increasing AKI events, whereas chronic use (≥180 d) was associated with 3.25 (95% CI, 1.78-5.97; P < 0.001) higher odds of AKI.

CONCLUSIONS

Prescriptions for NSAIDs were uncommon in this cohort but were associated with a significant increase in the risk of AKI, which was impacted by higher NSAID dose and longer NSAID durations.

Physical activity in elderly kidney transplant patients with multiple renal arteries

INTRODUCTION

Kidney transplantation (KT) is the gold standard for treatment of patients with end- stage-renal disease. To expand the donor reserve, it is necessary to use marginal/suboptimal kidneys.

METHODS

We retrospectively evaluated the short/long-term outcome of 34 KT elderly patients who received allografts with vascular abnormalities (MRA group), in comparison with 34 KT patients who received a kidney with a single renal artery (SRA group) pair-matched by age, length of time on dialysis, comorbidity and donor age.

RESULTS

All participants completed the International Physical Activity Questionnaire at KT, and then 4, 8, and 12 weeks after transplantation. Our data indicate that kidney with vascular anatomical variants may be successfully transplanted, since the overall rate of surgical complications was 20.6% in the SRA group and 17.6% in the MRA group and that the 5-year survival rate after KT was 100% in both groups.

CONCLUSIONS

The data also underline that individualized physical activity programs induced similar excellent results in both groups, improving physical capacities, arterial pressure, lipid metabolism, insulin sensitivity, quality of life and physical and mental status.