The clinical impact of the C-0/D ratio and the CYP3A5 genotype on outcome in tacrolimus treated kidney transplant recipients

Tacrolimus is metabolized by CYP3A4 and CYP3A5 enzymes. Patients expressing CYP3A5 (in Caucasian patients about 15% of the population but more frequent in African Americans and Asians) have a dose requirement that is around 50% higher than non-expressers to reach the target concentration. CYP3A5 expressers can be considered fast metabolizers. The trough concentration/dose (C-0/D) ratio of tacrolimus has recently been proposed as a prognostic marker for poor outcome after kidney transplantation. Patients with a low C-0/D ratio (also referred to as fast metabolizers) seem to have more tacrolimus-related nephrotoxicity, more BK-viremia, and a lower graft survival. At first sight, the expression of CYP3A5 and a low C-0/D ratio seem to be overlapping factors, both pointing towards patients in whom a higher tacrolimus dose is needed to reach the tacrolimus target concentration. However, there are important differences, and these differences may explain why the impact of the C-0/D ratio on long term outcome is stronger than for CYP3A5 genotype status. Patients with a low C-0/D ratio require a high tacrolimus dose and are exposed to high tacrolimus peak concentrations. The higher peak exposure to tacrolimus (and/or its metabolites) may explain the higher incidence of nephrotoxicity, BK-viremia and graft loss. A potential confounder is the concurrent maintenance treatment of corticosteroids, as steroids are sometimes continued in patients at high immunological risk. Steroids induce the metabolism of tacrolimusviapregnane X receptor mediated increased CYP3A4 expression, resulting in lower tacrolimus C-0/D ratio in high risk patients. Also non-adherence may result in lower C-0/D ratio which is also associated with poor outcome. The C-0/D ratio of tacrolimus does seem to identify a group of patients with increased risk of poor outcome after kidney transplantation. Our recommendation is to monitor tacrolimus peak concentrations in these patients, and if these are high then target slightly lower pre-dose concentrations. Another possibility would be to switch to a prolonged release formulation or to dose the drug more frequently, in smaller doses, to avoid high peak concentrations.Nephrolog

Donor type and 3-month hospital readmission following kidney transplantation: results from the Netherlands organ transplant registry

Clinical epidemiolog

Deposition of the membrane attack complex in healthy and diseased human kidneys

The membrane attack complex-also known as C5b-9-is the end-product of the classical, lectin, and alternative complement pathways. It is thought to play an important role in the pathogenesis of various kidney diseases by causing cellular injury and tissue inflammation, resulting in sclerosis and fibrosis. These deleterious effects are, consequently, targeted in the development of novel therapies that inhibit the formation of C5b-9, such as eculizumab. To clarify how C5b-9 contributes to kidney disease and to predict which patients benefit from such therapy, knowledge on deposition of C5b-9 in the kidney is essential. Because immunohistochemical staining of C5b-9 has not been routinely conducted and never been compared across studies, we provide a review of studies on deposition of C5b-9 in healthy and diseased human kidneys. We describe techniques to stain deposits and compare the occurrence of deposits in healthy kidneys and in a wide spectrum of kidney diseases, including hypertensive nephropathy, diabetic nephropathy, membranous nephropathy, IgA nephropathy, lupus nephritis, C3 glomerulopathy, and thrombotic microangiopathies such as the atypical hemolytic uremic syndrome, vasculitis, interstitial nephritis, acute tubular necrosis, kidney tumors, and rejection of kidney transplants. We summarize how these deposits are related with other histological lesions and clinical characteristics. We evaluate the prognostic relevance of these deposits in the light of possible treatment with complement inhibitors.Nephrolog

The effect of glycemic control on renal triglyceride content assessed by proton spectroscopy in patients with type 2 diabetes mellitus: a single-center parallel-group trial

Objective: Ectopic lipid accumulation in the kidney (fatty kidney) is a potential driver of diabetic kidney disease, and tight glycemic control can reduce risk of diabetic nephropathy. We assessed whether glycemic control influences renal triglyceride content (RTGC). Furthermore, we compared glucagon-like peptide-1 receptor agonist liraglutide versus standard glucose-lowering therapy. Design andMethods: In this single-center parallel-group trial, patients with type 2 diabetes mellitus were randomized to liraglutide or placebo added to standard care (metformin/sulfonylurea derivative/insulin). Changes in RTGC after 26 weeks of glycemic control measured by proton spectroscopy and difference in RTGC between treatment groups were analyzed.Results: Fifty patients with type 2 diabetes mellitus were included in the baseline analysis (mean age, 56.5 +/- 9.1 years; range, 33-73 years; 46% males). Seventeen patients had baseline and follow-up measurements. Mean glycated hemoglobin was 7.8 +/- 0.8%, which changed to 7.3 +/- 0.9% after 26 weeks of glycemic control irrespective of treatment group (P = .046). Log-transformed RTGC was -0.68 +/- 0.30% and changed to -0.83 +/- 0.32% after 26 weeks of glycemic control irrespective of treatment group (P = .049). A 26-week-to-baseline RTGC ratio (95% confidence interval) was significantly different between liraglutide (-0.30 [-0.50, -0.09]) and placebo added to standard care (-0.003 [-0.34, 0.34]) (P = .04).Conclusion: In this exploratory study, we found that 26 weeks of glycemic control resulted in lower RTGC, in particular for liraglutide; however, larger clinical studies are needed to assess whether these changes reflect a true effect of glycemic control on fatty kidney. (C) 2020 The Authors. Published by Elsevier Inc. on behalf of the National Kidney Foundation, Inc.Cardiovascular Aspects of Radiolog

Associations between normal range albuminuria, renal function and cardiovascular function in a population-based imaging study

Nephrolog

The association of glucose metabolism and kidney function in middle-aged adults

Background. Previous clinical studies have shown that various measures of glucose metabolism are associated with a risk of chronic kidney disease in different populations, but results were not consistent. In this study we assessed measures of glucose metabolism and their association with kidney function in a population-based study.Methods. The Netherlands Epidemiology of Obesity study is a population-based cohort study of middle-aged men and women. We categorized the study population according to glycaemic levels into normoglycaemia (reference group), pre-diabetes mellitus (pre-DM), known DM and newly diagnosed DM. Outcome variables were serum creatinine, estimated glomerular filtration rate (eGFR), glomerular hyperfiltration (defined as an eGFR >90th percentile; >102mL/min/1.73m(2)) and micro-albuminuria. We examined the association between measures of glucose metabolism [fasting glucose, haemoglobin A1c (HbA1c), fasting insulin, glucose area under the curve (AUC), insulin AUC, Homoeostatic Model Assessment of Insulin Resistance (HOMA-IR), HOMA of beta-cell function (HOMA-B) and disposition index] and measures of kidney function.Results. Of the total population (N=6338), 55% of participants were classified as normoglycaemic (reference), 35% as pre-DM, 7% as DM and 4% as newly diagnosed DM. Compared with the reference group, diagnosed and newly diagnosed DMs were associated with a slightly higher trend in eGFR {+2.1mL/min/1.73m(2) [95% confidence interval (CI) -0.2-4.4] and +2.7mL/min/1.73m(2) [95% CI -0.3-5.7], respectively}. A 1% higher HbA1c was associated with increased odds of hyperfiltration [odds ratio (OR) 1.41 (95% CI 1.06-1.88)]. Higher levels of fasting plasma glucose, AUC glucose and HOMA-B were associated with hyperfiltration. Fasting insulin, AUC insulin and HOMA-IR were not associated with hyperfiltration. The OR of microalbuminuria was 1.21 (95% CI 1.04-1.42) per mmol/L higher fasting glucose concentrations.Conclusions. Both fasting and post-prandial glucose and HOMA-B, but not measures of insulin resistance, were associated with glomerular hyperfiltration, while fasting glucose was also associated with microalbuminuria.Nephrolog

Drug-induced Fanconi syndrome associated with fumaric acid esters treatment for psoriasis: A case series

Background: Fumaric acid esters (FAEs), an oral immunomodulating treatment for psoriasis and multiple sclerosis, have been anecdotally associated with proximal renal tubular dysfunction due to a drug-induced Fanconi syndrome. Few data are available on clinical outcomes of FAE-induced Fanconi syndrome. Methods: Descriptive case series with two cases of Fanconi syndrome associated with FAE treatment diagnosed at two Dutch university nephrology departments, three cases reported at the Dutch and German national pharmacovigilance databases and six previously reported cases. Results: All 11 cases involved female patients with psoriasis. The median age at the time of onset was 38 years [interquartile range (IQR) 37-46]. Patients received long-term FAEs treatment with a median treatment duration of 60 months (IQR 28-111). Laboratory tests were typically significant for low serum levels of phosphate and uric acid, while urinalysis showed glycosuria and proteinuria. Eight (73%) patients had developed a hypophosphataemic osteomalacia and three (27%) had pathological bone fractures. All patients discontinued FAEs, while four (36%) patients were treated with supplementation of phosphate and/or vitamin D. Five (45%) patients had persisting symptoms despite FAEs discontinuation. Conclusions: FAEs treatment can cause drug-induced Fanconi syndrome, but the association has been reported infrequently. Female patients with psoriasis treated long term with FAEs seem to be particularly at risk. Physicians treating patients with FAEs should be vigilant and monitor for the potential occurrence of Fanconi syndrome. Measurement of the urinary albumin:total protein ratio is a suggested screening tool for tubular proteinuria in Fanconi syndrome

Age and gender differences in symptom experience and health-related quality of life in kidney transplant recipients: a cross-sectional study

Background Health-related quality of life (HRQOL) is an increasingly important patient-reported outcome in kidney transplant recipients (KTRs). This study explored relationships between symptom prevalence and burden with HRQOL, and age and gender differences in symptom experience. Methods Eligible Dutch KTRs transplanted in Leiden University Medical Center were invited for this cross-sectional study. HRQOL, and occurrence and burden of 62 symptoms were measured using validated questionnaires. Univariate and multivariate regression analysis were used for investigating the associations of symptom experience with mental and physical HRQOL, and differences in symptom experience between genders and KTRs of diverse age groups. Results A total of 631 KTRs were analyzed; the mean (standard deviation) age was 61.3 (11.3) years, and 62% were male. The median (interquartile range) number of symptoms was 14 (7-22), with a burden of 20 (8-37; range 0-244). Per extra symptom, physical and mental HRQOL decreased [-0.41 (-0.50; -0.31) and -0.51 (-0.59; -0.42), respectively, P 50-65 >= 65 years) feelings of depression and both female and younger KTRs reported higher symptom prevalence concerning changes in physical appearance. Conclusion KRTs' symptom experience differed depending on gender and age, highlighting the need to develop tailored treatment strategies to reduce symptom experience and subsequently improve HRQOL.Nephrolog

Tacrolimus and mycophenolic acid exposure are associated with biopsy-proven acute rejection: a study to provide evidence for longer-term target ranges

Evidence to define target ranges for tacrolimus (Tac) and mycophenolic acid (MPA) exposure after the first year of kidney transplantation is limited. We investigated the association of measurements at 1 year and repeated measurements of real-world Tac-trough levels (C-0) and abbreviated area under the curve from zero to 12 hours (AUC(0-12h)) of Tac and MPA with biopsy-proven acute rejection (BPAR) between years 1 and 3 post-transplant in 968 kidney transplant recipients (KTRs). Thirty-five (3.6%) out of 968 KTRs experienced BPAR. Both Tac-AUC(0-12h) (hazard ratio (HR): 0.39, 95% confidence interval (CI): 0.30-0.50, P < 0.001), Tac-C-0 (HR: 0.46, 95% CI: 0.38-0.57, P < 0.001) and MPA-AUC(0-12h) at 1 year (HR: 0.80, 95% CI: 0.68-0.94, P = 0.006), as well as repeated measurements of Tac-C-0 (HR: 0.70, 95% credibility interval (CrI): 0.61-0.82, P < 0.001), and of MPA-AUC(0-12h) (HR: 0.75, 95% CrI: 0.62-0.93, P < 0.001) were associated with BPAR. In our population, the recommended target range for Tac-AUC(0-12h) at 1 year would be 75-95 ng*hour/mL and a Tac-C-0 5-7 ng/mL. The Tac-AUC(0-12h) predicted BPAR better than Tac-C-0 and identified KTRs with over- or underexposure despite supposedly adequate Tac-C-0. We did not find evidence to recommend another target than the consensus range of 30-60 mg*hour/L for MPA-AUC(0-12h) after the first year of transplantation. To our knowledge, this is a first study on the simultaneous exposure of Tac and MPA at year 1 and subsequent BPAR up to year 3, which may help define the therapeutic target window for the longer term.Personalised Therapeutic

Severe COVID-19 in a renal transplant recipient: a focus on pharmacokinetics

The current coronavirus disease 2019 (COVID-19) pandemic requires extra attention for immunocompromised patients, including solid organ transplant recipients. We report on a case of a 35-year-old renal transplant recipient who suffered from a severe COVID-19 pneumonia. The clinical course was complicated by extreme overexposure to the mammalian target of rapamycin inhibitor everolimus, following coadministration of chloroquine and lopinavir/ritonavir therapy. The case is illustrative for dilemmas that transplant professionals may face in the absence of evidence-based COVID-19 therapy and concurrent pressure for exploration of experimental pharmacological treatment options. However, the risk-benefit balance of experimental or off-label therapy may be weighed differently in organ transplant recipients than in otherwise healthy COVID-19 patients, owing to their immunocompromised status and potential drug interactions with immunosuppressive therapy. With this case report, we aimed to achieve increased awareness and improved management of drug-drug interactions associated with the various treatment options for COVID-19 in renal transplant patients.Transplant surger