Prevalence and clinical correlates of hyperkalemia in stable kidney transplant recipients.

Although hyperkalemia (HK) is often associated with adverse clinical outcomes in renal patients, few studies are available in the setting of kidney transplantation. Therefore, we evaluated prevalence and clinical correlates of HK in stable kidney transplant recipients (KTRs) on standard of care immunosuppressive therapy. We studied 160 stable KTRs (post-transplant vintage 46.6 ± 16.6 months), most of whom (96.2%) on calcineurin inhibitor (CNI)-based immunosuppressive therapy. HK was defined as plasma potassium levels above 5 mEq/L, confirmed in two consecutive samples. Office blood pressure was measured, and renal graft function was expressed by estimated glomerular filtration rate (eGFR), calculated according to the CKD-EPI formula. HK prevalence was 8.8%, and plasma K above 5.5 mEq/L was found in 2.5% of all KTRs. In the univariate logistic regression analysis HK was significantly associated with serum urea concentration (OR 1.03, 95% CI 1.01-1.05 for each 1 mg/dL increase), tCO2 (OR 0.77, 95% CI 0.66-0.90 for each 1 mmol/L increase), the presence of arterial hypertension (OR 4.01, 95% CI 1.3-12.64), the use of RAAS inhibitors (OR 5.26, 95% CI 1.6-17.7), and eGFR less than 30 ml/min/1.73 m2 (OR 7.51, 95% CI 2.37-23.77). By multivariable backward stepwise regression analysis, the presence of metabolic acidosis (OR 0.83, 95% CI 0.69-0.99, P = 0.04), arterial hypertension (OR 4.65 95% CI 1.01-17.46 P = 0.03), and to be administered RAAS inhibitors (OR 6.11, 95% CI 1.03-25.96 P = 0.03) remained significantly associated with HK. We conclude that in stable KTRs the prevalence of HK is about 9%, slightly lower than previously reported. Moreover, it is not associated with eGFR, but with metabolic acidosis, arterial hypertension, and the use of RAAS inhibitors.

Everolimus for BKV nephropathy in kidney transplant recipients: a prospective, controlled study.

There is no specific therapy for polyoma BK virus nephropathy (BKVN) in kidney transplant recipients, a condition associated with poor outcomes. Everolimus showed promising antiviral effects, but data from prospective studies are limited. Therefore, we converted ten consecutive kidney transplant recipients with biopsy-proven BKVN from standard exposure Calcineurin inhibitors and Mycophenolate to Everolimus and reduced exposure Calcineurin inhibitors. Ten patients not administered Everolimus, on reduced exposure Calcineurin inhibitor and halved MPA doses served as controls. All kidney transplant recipients continued steroid therapy. Each patient underwent kidney graft biopsy, BKV replication by PCR, and de novo DSA determination. During a 3-year follow-up no graft loss occurred in kidney transplant recipients on Everolimus but it was observed in 5/10 controls (P = 0.032). eGFR improved on Everolimus and worsened in controls (between group difference + 25.6 ml/min/1.73 m2, 95% CI 10.5-40.7, P = 0.002). BKV replication declined in the Everolimus group alone (from 6.4 ± 0.8 to 3.6 ± 1.6 Log 10 genomic copies, P = 0.0001), and we found a significant inverse relationship between eGFR and BKV genomic copy changes (P = 0.022). Average Calcineurin inhibitors trough levels did not differ between the two study groups during follow-up. By multivariable Cox regression analysis, Everolimus treatment resulted the only significant predictor of survival free of a combined endpoint of graft loss and 57% eGFR reduction (P = 0.02). Kidney transplant recipients on Everolimus had a higher survival free of adverse graft outcome (log-rank test, P = 0.009). In conclusion an Everolimus-based immunosuppressive protocol with minimization of Calcineurin inhibitors and antimetabolite discontinuation effectively treated BKVN in kidney transplant recipients.

[mTOR inhibitors in kidney transplantation].

A changing paradigm of treatment of kidney transplant recipients is a new, wider approach to immunosuppression, which should take into account both antiviral and anticancer effects, in addition to cardiovascular protection. Recent observations suggest that the early introduction of mammalian target of rapamycin inhibitors (mTORi) in association with low dose CNI may offer many of these effects. The present manuscript summarizes benefits and contraindications of combinations with mTORi in kidney transplant immunosuppressive strategies.

Prevention of non-melanoma skin cancers with nicotinamide in transplant recipients: a case-control study.

Nicotinamide is the precursor of nicotinamide adenine dinucleotide (NAD+), an essential cofactor for adenosine triphosphate (ATP) production. It has recently been reported to be effective in reducing the rates of new non-melanoma skin cancers (NMSCs) and actinic keratosis (AKs). We studied the efficacy of oral nicotinamide as treatment for AKs in transplant recipients. We recruited 38 transplant (eight liver and 30 kidney) patients with single or multiple AKs. Nineteen patients were randomly assigned to Group 1 and took nicotinamide 500 mg/daily (cases); the other 19 patients were randomly assigned to Group 2 without nicotinamide (controls). At baseline, AKs were identified, measured, and photographed for follow-up. Five patients underwent an AK biopsy for histopathology. Statistical analyses were performed using the Student t test. At baseline, no statistically significant differences were observed regarding AK size between the two groups. After six months, among the cases, AKs had significantly decreased in size in 18/19 patients (88%). Among these 18 patients, seven patients (42%) had shown complete clinical regression and no patient developed new AKs. Conversely, among the controls, 91% showed an increase in AK size and/or developed new AKs. Seven pre-existing AKs progressed to squamous-cell carcinoma. Nicotinamide appears to be effective in preventing and treating AKs, although the mechanisms are still unclear. Further studies with a larger sample of organ transplant recipients and a longer follow-up period are needed to further support our conclusions.

Regression of asymptomatic cardiomyopathy and clinical outcome of renal transplant recipients: a long-term prospective cohort study.

BACKGROUND: Asymptomatic left ventricular hypertrophy (LVH) is highly prevalent and associated with an adverse outcome in renal transplant recipients (RTRs). Nonetheless, there are currently no available studies analyzing the effect of LVH regression on solid clinical endpoints in these patients. METHODS: This study is the prospective observational extension of two randomized controlled trials aimed at assessing the effect of active intervention on post-transplant LVH in RTRs. We evaluated the incidence of a composite of death and any cardiovascular (CV) or renal event in 60 RTRs in whom LVH regression was observed and in 40 whose LVH remained unchanged or worsened. RESULTS: During an 8.4 ± 3.5-year follow-up, 8 deaths, 18 CV events and 6 renal events occurred in the entire cohort. Multivariable analysis showed that age [hazard ratio (HR) 1.07, 95% confidence interval (CI) 1.03-1.12 each 1 year, P = 0.002] and LVH regression (HR 0.42, 95% CI 0.22-0.87, P = 0.019) were significant predictors of the composite endpoint. Kaplan-Meier estimates showed better survival rates in patients in whom actual LVH regression was achieved (P < 0.001, log-rank test). Age (HR 1.09, 95% CI 1.03-1.15 each 1 year, P = 0.004), better graft function (HR 0.95, 95% CI 0.91-0.99 each 1 mL/min/1.73 m(2) increase in estimated glomerular filtration rate, P = 0.03) and LVH regression (HR 0.41, 95% CI 0.22-0.79, P = 0.01) were significant predictors of the CV endpoint. Patients with a left ventricular mass index decrease also showed better cardiac event-free survival (P = 0.0022, log-rank test). CONCLUSIONS: This is the first study to demonstrate that LVH regression, regardless of the therapeutic strategy adopted to achieve it, portends better long-term clinical outcome in RTRs.

De novo post-transplant thrombotic microangiopathy localized only to the graft in autosomal dominant polycystic kidney disease with thrombophilia.

INTRODUCTION: Thrombotic microangiopathy (TMA) is a serious complication of renal transplantation and is mostly related to the prothrombotic effect of calcineurin inhibitors (CNIs). A subset of TMA (29%-38%) is localized only to the graft. Case 1: A young woman suffering from autosomal dominant polycystic kidney disease (ADPKD) underwent kidney transplant. After 2 months, she showed slow renal deterioration (serum creatinine from 1.9 to 3.1 mg/dl), without hematological signs of hemolytic-uremic syndrome (HUS); only LDH enzyme transient increase was detected. Renal biopsy showed TMA: temporary withdraw of tacrolimus and plasmapheresis was performed. The renal function recovered (serum creatinine 1.9 mg/dl). From screening for thrombophilia, we found a mutation of the Leiden factor V gene. Case 2: A man affected by ADPKD underwent kidney transplantation, with delay graft function; first biopsy showed acute tubular necrosis, but a second biopsy revealed TMA, while no altered hematological parameters of HUS was detected. We observed only a slight increase of lactate dehydrogenase (LDH) levels. The tacrolimus was halved and plasmapheresis was performed: LDH levels normalized within 10 days and renal function improved (serum creatinine from 9 to 2.9 mg/dl). We found a mutation of the prothrombin gene. Only a renal biopsy clarifies the diagnosis of TMA, but it is necessary to pay attention to light increasing level of LDH. CONCLUSION: Prothrombotic effect of CNIs and mTOR inhibitor, mutation of genes encoding factor H or I, anticardiolipin antibodies, vascular rejection, cytomegalovirus infection are proposed to trigger TMA; we detected mutations of factor II and Leiden factor V, as facilitating conditions for TMA in patients affected by ADPKD.

Effects of ACE inhibitors on long-term outcome of renal transplant recipients: a randomized controlled trial.

BACKGROUND: Available data on the role of renin-angiotensin system blockade in renal transplantation are inconclusive. Herein, we report the long-term results of a randomized controlled trial planned to evaluate the impact of angiotensin-converting enzyme inhibitors (ACE-i) on the cardiovascular outcome of renal transplant recipients (RTRs) receiving calcineurin inhibitors, steroids, and mycophenolate mofetil. METHODS: Thirty-six RTRs were allocated to receive ACE-i and 34 served as controls. Survival free of a composite endpoint consisting of death, major cardiovascular events, renal graft loss or creatinine doubling, and survival free of each single endpoint were analyzed in both groups according to a modified intention-to-treat analysis. RESULTS: During a 10-year follow-up, three patients died (one in the ACE-i group and two controls) and three lost their graft (two receiving ACE-i and one control). Three major cardiovascular events were observed in the ACE-i group and 12 among controls (P=0.008). At the end of observation, a significant increase in urinary protein excretion rate was only observed in controls (P=0.017).Compared with controls, RTRs administered ACE-i had significantly better survival free of the combined endpoint (P=0.0102, log-rank test) and free of major cardiovascular events (P=0.0027) without significant differences in renal outcome. By Cox regression analysis, ACE-i therapy resulted in the most powerful predictor of survival free of composite endpoint (hazard ratio, 0.165; 95% confidence interval, 0.053-0.512; P=0.0018) and survival free of major cardiovascular events (hazard ratio, 0.209; 95% confidence interval, 0.068-0.636; P=0.0059). CONCLUSIONS: Prolonged therapy with ACE-i was associated with better general and cardiovascular outcome of RTRs without detrimental effects on renal graft function.

Effect of everolimus on left ventricular hypertrophy of de novo kidney transplant recipients: a 1 year, randomized, controlled trial.

BACKGROUND: Although conversion from calcineurin inhibitors to mammalian target of rapamycin inhibitors proved to be effective in regressing left ventricular hypertrophy (LVH) in renal transplant recipients (RTRs) with chronic allograft dysfunction, there are currently no reports of randomized trials on this issue involving de novo RTRs administered everolimus (EVL). METHODS: This randomized, open-label, controlled trial evaluated the effect of EVL on the left ventricular mass index (LVMi) of 30 nondiabetic RTRs (21 men; age 28-65 years). Ten were allocated to EVL plus reduced-exposure cyclosporine A (CsA), and 20 to standard dose CsA. LVMi was assessed by echocardiography both at baseline and 1 year later. Blood pressure (BP), hemoglobin, serum creatinine, lipids, trough levels of immunosuppressive drugs, and daily proteinuria were also evaluated twice monthly. Antihypertensive therapy that did not include renin-angiotensin system blockers was administered to achieve BP less than or equal to 130/80 mm Hg. RESULTS: Changes in BP were similar in the two groups (between group difference 1.2 ± 5.7 mm Hg, P=0.84 for systolic, and -1.5 ± 3.7, P=0.69, for diastolic BP), whereas LVMi significantly decreased in the EVL group alone (between group difference 9.2 ± 3.1 g/m(2.7), P=0.005), due to a reduction in both the interventricular septum and the left ventricular posterior wall thickness. EVL therapy together with baseline LVMi were the only significant predictors of LVH regression according to a multivariate model that explained 49% of the total LVMi variance (P=0.0015). CONCLUSIONS: An immunosuppressive regimen consisting of EVL plus reduced exposure CsA proved to be effective in regressing LVH in RTRs regardless of BP, mainly by reducing left ventricular wall thickness.

Effect of early conversion from CNI to sirolimus on outcomes in kidney transplant recipients with allograft dysfunction.

BACKGROUND: Studies evaluating the effect of conversion from calcineurin inhibitor (CNI) to sirolimus (SRL) in renal transplant recipients (RTRs) have shown conflicting results, and only few short-term uncontrolled studies are available in patients with chronic allograft dysfunction. This is the first controlled study to evaluate long-term survival and both renal and cardiac outcomes in nondiabetic RTRs with allograft dysfunction who were converted from CNI to SRL. METHODS: We evaluated 13 RTRs with biopsy-proven allograft dysfunction who underwent early conversion from CNI to SRL, and 26 controls with normal graft function taking CNI. All continued both steroids and mycophenolate mofetil. SRL was titrated to trough levels of 4-8 ng/mL. Outcome measures included 3-year event-free survival, acute rejection rate and 3-year changes in Modification of Diet in Renal Disease (MDRD) Study equation estimated glomerular filtration rate (eGFR) and left ventricular mass index (LVMi) as assessed by echocardiography. RESULTS: Compared with controls, patients on SRL showed better 3-year event-free survival (p=0.024; log-rank test), significant eGFR increase (+5.5 ± 8.9 vs, -6.4 ± 14.7 ml/min per 1.73 m2, p=0.011), LVMi regression (-9.0 ± 7.6 g/m(2.7) vs. 1.0 ± 10.1 g/m(2.7), p=0.0038) and similar acute rejection rate. Three-year change in eGFR was the only significant predictor of event-free survival by Cox regression analysis (hazard ratio = 0.96; 95% confidence interval, 0.93-0.99; p=0.017), whereas SRL was the strongest predictor of both eGFR increase (beta coefficient, 0.342; p=0.01) and LVM reduction (beta coefficient, -0.609; p=0.0001) by multivariate regression analysis. CONCLUSIONS: Conversion from CNI to SRL in RTRs with allograft dysfunction proved to be associated with better survival, improved renal graft function and regression of cardiac hypertrophy.

Effect of sirolimus on left ventricular hypertrophy in kidney transplant recipients: a 1-year nonrandomized controlled trial.

BACKGROUND: Left ventricular hypertrophy (LVH) after renal transplantation may be affected by immunosuppressive therapy. STUDY DESIGN: Nonrandomized controlled trial evaluating the effect of sirolimus (SRL) on LVH of renal transplant recipients (RTRs). SETTING & PARTICIPANTS: 13 RTRs without diabetes who had received a single-kidney transplant from a deceased donor with chronic allograft dysfunction and biopsy-proven allograft nephropathy who were converted from calcineurin-inhibitor (CNI) to SRL treatment; 26 controls matched for age and year of transplantation who were not converted from CNI to SRL treatment. INTERVENTION: Conversion from CNI to SRL therapy. OUTCOMES & MEASUREMENTS: Left ventricular mass determination by using echocardiography at baseline and again 1 year later. Blood pressure (BP), hemoglobin level, serum creatinine level, uric acid level, lipid levels, trough levels of immunosuppressive drugs, and daily proteinuria were assessed at least twice monthly. Conventional antihypertensive therapy was used to achieve BP of 130/80 mm Hg or less. RESULTS: The study population included 26 men and 13 women (age, 25 to 66 years). Changes in BP were similar in the 2 groups (between-group difference, -4 +/- 5 mm Hg; P = 0.5 for systolic BP; -2 +/- 3; P = 0.6 for diastolic BP), whereas left ventricular mass significantly decreased in the SRL group alone (between-group difference, 8.6 +/- 2.4 g/m(2.7); P < 0.001) because of a decrease in both the interventricular septum and left ventricular posterior wall. LVH regressed in 12 of 13 patients on SRL therapy and 10 of 26 controls (P = 0.002). LIMITATIONS: Nonrandomized design. Single-center study with small sample size. CONCLUSIONS: Conversion from CNI to SRL therapy may regress LVH in RTRs regardless of BP changes, mainly by decreasing left ventricular wall thickness, thus suggesting nonhemodynamic-effect mechanisms of SRL on left ventricular mass.

Incidence of second primary cancer in transplanted patients.

BACKGROUND: Solid organ transplanted patients have a three- to fourfold higher lifetime risk of developing a cancer than the general population. However, the incidence of a second primary cancer in transplanted patients has never been studied, despite the fact that the presence of regular follow-ups and the increased survival of these patients make them a very attractive model. METHODS: We investigated the incidence of a second primary cancer (SPC) in 7,636 patients who underwent a kidney, liver, lung or heart transplant between 1970 and 2004, and were followed-up for 51,819 person-years. RESULTS: During the follow-up, 499 subjects developed a first cancer (annual incidence: 98.6 x 10,000 PY), and 22 of them developed a SPC (annual incidence: 3.9 x 10,000 PY). The annual incidence of a SPC in the transplanted patients who developed a first cancer was 107.8 x 10,000 PY, giving a standardized incidence ratio of 1.1 (95% CI: 0.83-1.41). CONCLUSIONS: This result shows that the incidence of the SPC was the same as the incidence of a first cancer. Our study does not indicate an increased risk of SPC in transplanted subjects who already suffered a first malignancy.

Bone disease in long-term renal transplant recipients with severe osteopenia: a cross-sectional study.

BACKGROUND: Fracture is a disabling clinical outcome after transplantation, but there is little histopathological information on long-term renal recipients with severe osteopenia. METHODS: Twenty kidney recipients (8.3+/-1.9 years after transplantation), 13 males and 7 females (five postmenopausal) with nearly normal renal function, affected by severe osteopenia (T-score: males= -4.9+/-0.28; females= -5.08+/-0.47) underwent bone biopsy and morphometric X-ray absorptiometry to evaluate vertebral fractures. RESULTS: Histopathological diagnosis was osteoporosis-osteopenia in seven patients, osteitis fibrosa in six, prevalent osteomalacic lesion in six, and "normal" bone in one patient. Significant increases in osteoid volume (OV/BV), osteoid surface, osteoblastic surface (ObS/BS) and osteoid thickness were observed. OV/BV and Obs/BS ratios were inversely correlated to cumulative doses of MPRED (r2=0.85 P<.0001 for both ratios), whereas age, sex, time after transplantation, iPTH levels, and cumulative cyclosporine A dose were not related to osteoblastic indices. Osteoclast surface was slightly increased. Widened mineralization lag times were observed, with normalcy of the bone formation rate. Half of the patients showed fractured vertebrae. No differences in T scores were found when patients were subdivided into groups "with" or "without" vertebral fractures. A higher prevalence of fractures was observed in patients with osteoporosis-osteopenia compared to other osteopathies (P<0.02). No relationships between bone volume versus T-scores were observed. CONCLUSIONS: In long-term renal transplant recipients, severe osteopenia does not predict osteoporosis alone. The main abnormality we found was an increase in osteoblastic activity with a slight mineralization defect. The heterogeneous bone illness we observed would suggest performing bone biopsy in these patients.