Cyclosporine nephrotoxicity

Safety and efficacy of immunosuppressive therapy for elderly patients with severe aplastic anaemia

Uncertainty remains regarding the safety and tolerability of immunosuppressive therapy (IST) with anti-thymocyte globulin (ATG) and cyclosporine (CSA) in older patients. We retrospectively analysed two prospective clinical trials of IST in treatment-naïve severe aplastic anaemia (SAA) to assess safety in older compared to younger patients. Patients ≥18 years of age who had received IST with ATG and CSA +/- eltrombopag (EPAG) were included. Pre-treatment baseline characteristics and co-morbidities were assessed as predictors of therapy-related complications in younger (<60 years) versus older (≥60 years) patients. Out of 245 eligible patients, 54 were older and 191 were younger. Older patients had a similar frequency of SAEs, ICU admissions and hospital length of stay compared to younger patients. Older patients had a higher frequency of cardiac events related to IST, but none resulted in death. Older patients had worse long-term overall survival, and more relapse and clonal evolution post-IST. However, older patients who responded to IST had a similar survival at a median follow-up to younger patients. Disease-related factors and limited therapeutic options in refractory disease likely contribute to poorer outcomes in older patients, not complications of upfront IST. Therefore, IST should be considered first-line therapy for most older SAA patients.

Managing the Patient with Psoriasis and Metabolic Comorbidities

Epidemiological data demonstrate strong associations between psoriasis and metabolic comorbidities, including obesity, hypertension, diabetes mellitus, dyslipidemia, and non-alcoholic fatty liver disease. The presence of metabolic comorbidities significantly influences the selection and effectiveness of pharmacological treatments. Some drugs should be prescribed with caution in patients with metabolic comorbidities because of an increased risk of adverse events, while others could have a reduced effectiveness. The aim of this narrative review is to highlight the challenges that healthcare professionals may face regarding the management of psoriasis in patients with metabolic comorbidities. In the first part of the article, the epidemiological association between psoriasis and metabolic comorbidities and their pathogenetic mechanisms is summarized. The second part describes the efficacy and safety profile of conventional and biologic drugs in patients with selected metabolic comorbidities including obesity, non-alcoholic fatty liver disease/hepatic steatosis, and diabetes. Finally, the role of pharmacological and non-pharmacological interventions, such as diet, alcohol abstinence, physical activity, and smoking avoidance is discussed. In conclusion, the choice of the best approach to manage patients with psoriasis with metabolic comorbidities should encompass both tailored pharmacological and individualized non-pharmacological interventions.

Cyclosporin-induced hypertension is associated with the up-regulation of Na+-K+-2Cl- cotransporter (NKCC2)

BACKGROUND

The use of cyclosporin A (CsA) is hampered by the development of nephrotoxicity including hypertension, which is partially dependent on renal sodium retention. To address this issue, we have investigated in vivo sodium reabsorption in different nephron segments of CsA-treated rats through micropuncture study coupled to expression analyses of sodium transporters. To translate the findings in rats to human, kidney-transplanted patients having CsA treatment were enrolled in the study.

METHODS

Adult male Sprague-Dawley rats were treated with CsA (15 mg/kg/day) for 21 days, followed by micropuncture study and expression analyses of sodium transporters. CsA-treated kidney-transplanted patients with resistant hypertension were challenged with 50 mg furosemide.

RESULTS

CsA-treated rats developed hypertension associated with reduced glomerular filtration rate. In vivo microperfusion study demonstrated a significant decrease in rate of absolute fluid reabsorption in the proximal tubule but enhanced sodium reabsorption in the thick ascending limb of Henle's loop (TAL). Expression analyses of sodium transporters at the same nephron segments further revealed a reduction in Na+-H+ exchanger isoform 3 (NHE3) in the renal cortex, while TAL-specific, furosemide-sensitive Na+-K+-2Cl- cotransporter (NKCC2) and NHE3 were significantly upregulated in the inner stripe of outer medulla. CsA-treated patients had a larger excretion of urinary NKCC2 protein at basal condition, and higher diuretic response to furosemide, showing increased FeNa+, FeCl- and FeCa2+ compared with both healthy controls and FK506-treated transplanted patients.

CONCLUSION

Altogether, these findings suggest that up-regulation of NKCC2 along the TAL facilitates sodium retention and contributes to the development of CsA-induced hypertension.

Adverse Drug Events after Kidney Transplantation

Introduction: Kidney transplantation stands out as the optimal treatment for patients with end-stage kidney disease, provided they meet specific criteria for a secure outcome. With the exception of identical twin donor-recipient pairs, lifelong immunosuppression becomes imperative. Unfortunately, immunosuppressant drugs, particularly calcineurin inhibitors like tacrolimus, bring about adverse effects, including nephrotoxicity, diabetes mellitus, hypertension, infections, malignancy, leukopenia, anemia, thrombocytopenia, mouth ulcers, dyslipidemia, and wound complications. Since achieving tolerance is not feasible, patients are compelled to adhere to lifelong immunosuppressive therapies, often involving calcineurin inhibitors, alongside mycophenolic acid or mTOR inhibitors, with or without steroids. Area covered: Notably, these drugs, especially calcineurin inhibitors, possess narrow therapeutic windows, resulting in numerous drug-related side effects. This review focuses on the prevalent immunosuppressive drug-related side effects encountered in kidney transplant recipients, namely nephrotoxicity, post-transplant diabetes mellitus, leukopenia, anemia, dyslipidemia, mouth ulcers, hypertension, and viral reactivations (cytomegalovirus and BK virus). Additionally, other post-kidney-transplantation drugs such as valganciclovir may also contribute to adverse events such as leukopenia. For each side effect, we propose preventive measures and outline appropriate treatment strategies.

Recent Advances in Drug Discovery Toxicology

Major advances in scientific discovery and insights that stem from the development and use of new techniques and models can bring remarkable progress to conventional toxicology. Although animal testing is still considered as the "gold standard" in traditional toxicity testing, there is a necessity for shift from animal testing to alternative methods regarding the drug safety testing owing to the emerging state-of-art techniques and the proposal of 3Rs (replace, reduce, and refine) towards animal welfare. This review describes some recent research methods in drug discovery toxicology, including in vitro cell and organ-on-a-chip, imaging systems, model organisms (C. elegans, Danio rerio, and Drosophila melanogaster), and toxicogenomics in modern toxicology testing.

Acute Kidney Injury in Kidney Transplant Patients in Intensive Care Unit: From Pathogenesis to Clinical Management

Kidney transplantation is the first-choice treatment for end-stage renal disease (ESRD). Kidney transplant recipients (KTRs) are at higher risk of experiencing a life-threatening event requiring intensive care unit (ICU) admission, mainly in the late post-transplant period (more than 6 months after transplantation). Urosepsis and bloodstream infections account for almost half of ICU admissions in this population; in addition, potential side effects related to immunosuppressive treatment should be accounted for cytotoxic and ischemic changes induced by calcineurin inhibitor (CNI), sirolimus/CNI-induced thrombotic microangiopathy and posterior reversible encephalopathy syndrome. Throughout the ICU stay, Acute Kidney Injury (AKI) incidence is common and ranges from 10% to 80%, and up to 40% will require renal replacement therapy. In-hospital mortality can reach 30% and correlates with acute illness severity and admission diagnosis. Graft survival is subordinated to baseline estimated glomerular filtration rate (eGFR), clinical presentation, disease severity and potential drug nephrotoxicity. The present review aims to define the impact of AKI events on short- and long-term outcomes in KTRs, focusing on the epidemiologic data regarding AKI incidence in this subpopulation; the pathophysiological mechanisms underlying AKI development and potential AKI biomarkers in kidney transplantation, graft and patients' outcomes; the current diagnostic work up and management of AKI; and the modulation of immunosuppression in ICU-admitted KTRs.

Acute kidney injury and chronic kidney disease in umbilical cord blood transplant recipients

Introduction

Acute kidney injury (AKI) is a frequent early complication post hematopoietic stem cell transplant (HSCT), associated with high morbidity and mortality. Cord blood transplant (CBT) recipients are potentially exposed to more nephrotoxic insults, compared to patients undergoing HSCT from other donor sources. We aimed to identify risk factors for AKI in patients undergoing CBT. We also aimed to identify the impact of AKI on chronic kidney disease (CKD) and survival outcomes by one-year post-CBT.

Methods

Adults and children who underwent a first CBT at our Institution were retrospectively evaluated. AKI was staged according to Kidney Disease Improving Global Outcomes (KDIGO) definitions. Cox regression models were used to estimate the association of demographic factors and post-CBT parameters with the cause-specific hazard of AKI.

Results

We identified 276 patients. Median age was 32 years, 28% (77/276) were children (<18 years) and 129 (47%) were white. A myeloablative conditioning regimen was administered to 243 patients (88%) and 248 (90%) received cyclosporine for GVHD prophylaxis. One-hundred and eighty-six patients (67%) developed AKI by day 60 post-transplant, with 72 (26%) developing severe AKI (stage 2 and 3). In a multivariable analysis, each increase in bilirubin level of 1 mg/dL was associated with a 23% increase in the risk of severe AKI (adjusted HR 1.23, 95% CI 1.13 - 1.34, p<.0001). Conversely, systemic steroid administration appeared to be protective of severe AKI (unadjusted HR 0.36, 95% CI 0.18 - 0.72, p=.004) in a univariate model . Two-hundred-forty-seven patients were evaluable at the one-year time point. Among those, 100 patients (40%) developed CKD one-year post-CBT. Severe AKI was associated with a higher hazard of non-relapse mortality (adjusted HR=3.26, 95% CI 1.65-6.45, p=.001) and overall mortality (adjusted HR=2.28, 95% CI 1.22-4.27, p=.01).

Discussion

AKI is a frequent complication after CBT and is associated with worse outcomes. Questions remain as to the mechanism of the protective role of steroids on kidney function in the setting of CBT.

Protective effect of silymarin on tacrolimus-induced kidney and liver toxicity

BACKGROUND

Tacrolimus (FK506) is an immunosuppressive agent and has toxic side effects such as nephrotoxicity, hepatotoxicity, and neurotoxicity. In our study, we aimed to investigate the protective effect of silymarin on renal and hepatic toxicity considered to be tacrolimus related.

METHODS

In this 6-week experimental study, 46 eight-week-old healthy male rats were used. The groups comprised the Control (healthy rats, n = 6), Tac (tacrolimus 1 mg/kg, n = 8), silymarin 100 mg/kg (SLI 100 mg/kg n = 8), Tac + SLI 100 (tacrolimus 1 mg/kg + SLI 100 n = 8), SLI 200 (SLI 200 mg/kg n = 8), and Tac + SLI 200 (tacrolimus 1 mg/kg + SLI 200 mg/kg n = 8). After 6 weeks, all rats were sacrificed, and the tissue follow-up procedure was performed for kidney and liver tissues, histopathology, and in situ TUNEL analysis. Blood samples were analyzed for the total antioxidant capacity (TAC), total oxidant capacity (TOC), alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), albumin, total bilirubin, creatine.

RESULTS

Histopathological findings of kidney and liver tissue of rats were determined to increase statistically in Tac group compared to SLI 1 00 and SLI 200 groups (P < 0.05). In addition, the Tac + SLI 100 and Tac + SLI 200 groups were found to be statistically similar to the Control group (P > 0.05). The in situ TUNEL method showed that the tacrolimus increased apoptosis while the silymarin decreased it. TOC levels increased statistically in Tac groups compared to silymarin-treated groups (P < 0.05). Although the TAC level was not statistically significant among the experimental groups (P > 0.05), the lowest was measured in the Tac group. The ALT, AST, GGT, total bilirubin, and creatine values were higher in the Tac group than in the silymarin groups (P < 0.05). There was no statistically significant difference between the groups with regard to the albumin level (P > 0.05).

CONCLUSION

In our study, we determined that tacrolimus caused damage to kidney and liver tissue. Histopathological, biochemical and apoptotic findings show that silymarin has a protective effect against nephrotoxicity and hepatotoxicity caused by tacrolimus.

2-Methoxyestradiol TPGS Micelles Attenuate Cyclosporine A-Induced Nephrotoxicity in Rats through Inhibition of TGF-β1 and p-ERK1/2 Axis

The immunosuppressant cyclosporine A (CSA) has been linked to serious renal toxic effects. Although 2-methoxyestradiol (2ME) possesses a wide range of pharmacological abilities, it suffers poor bioavailability after oral administration. The purpose of this study was to evaluate the potential of 2ME loaded D-ɑ-tocopheryl polyethylene glycol succinate (TPGS) micelles to prevent CSA-induced nephrotoxicity in rats. A 2ME-TPGS was prepared and showed particle size of 44.3 ± 3.5 nm with good entrapment efficiency and spherical structures. Male Wistar rats were divided into 5 groups, namely: Control, Vehicle, CSA, CSA + 2ME-Raw, and CSA + 2ME-Nano. CSA was injected daily at a SC dose of 20 mg/kg. Both 2ME-Raw and 2ME-Nano were given daily at oral doses of 5 mg/kg. Treatments continued for three successive weeks. 2ME-TPGS exerted significant protective effects against CSA nephrotoxicity. This was evidenced in ameliorating deterioration of renal functions, attenuation of pathological changes in kidney tissues, exerting significant anti-fibrotic, antioxidant, and anti-inflammatory effects together with significant anti-apoptotic effects. Western blot analyses showed both 2ME-Raw and 2ME-Nano significantly inhibited protein expression of TGF-β1 and phospho-ERK (p-ERK). It was observed that 2ME-TPGS, in almost all experiments, exerted superior protective effects as compared with 2ME-Raw. In conclusion, 2ME loaded in a TPGS nanocarrier possesses significant protective activities against CSA-induced kidney injury in rats. This is attributable to 2ME anti-fibrotic, antioxidant, anti-inflammatory, and anti-apoptotic activities which are mediated at least partly by inhibition of TGF-β1/p-ERK axis.

Elevated Urinary Tissue Inhibitor Of Metalloproteinase-2 And Insulin-Like Growth Factor Binding Protein-7 Predict Drug-Induced Acute Kidney Injury

BACKGROUND

Urinary tissue inhibitor of metalloproteinase-2 (TIMP2) and insulin-like growth factor binding protein-7 (IGFBP7) predict severe acute kidney injury (AKI) in critical illness. Earlier but subtle elevation of either biomarker from nephrotoxicity may predict drug-induced AKI.

METHODS

A prospective study involving serial urine collection in patients treated with vancomycin, aminoglycosides, amphotericin, foscarnet, or calcineurin inhibitors was performed. Urinary TIMP2 and IGFBP7, absolute levels, normalized with urine creatinine were examined in days leading to AKI onset by KDIGO criteria in cases, or at final day of nephrotoxic therapy in non-AKI controls who were matched for age, baseline kidney function and nephrotoxic exposure.

RESULTS

Urinary biomarker analyses were performed in 21 AKI patients and 28 non-AKI matched-controls; both groups had comparable baseline kidney function and duration of nephrotoxic drug therapy. Significantly higher absolute, normalized, and composite levels of TIMP2 and IGFBP7 were observed in AKI cases versus controls as early as 2-3 days before AKI onset (all P<0.05); >70% of patients with corresponding levels above 75th percentile developed AKI. Normalized TIMP2 at 2-3 days pre-AKI predicted AKI with the highest average AUROC of 0.81, followed by that of composite [TIMP2]x[IGFBP7] (0.78) after cross-validation. [TIMP2]x[IGFBP7] >0.01 (ng/mL)2 /1000 predicted AKI with a sensitivity of 79% and specificity of 60%.

CONCLUSION

Elevated urinary TIMP2 or IGFBP7 predicts drug-induced AKI with a lead-time of 2-3 days; an opportune time for interventions to reduce nephrotoxicity.

[Epidemiology and Causes of Acute Renal Failure and Transition to Chronic Kidney Disease]

Acute kidney injury (AKI) refers to an acute functional deterioration of the kidneys, which leads to retention of urinary substances, dysregulation of the electrolyte and acid-base balance, and disturbance of fluids. Although didactically helpful, the oversimplified AKI classification of prerenal/renal/postrenal is currently considered obsolete. Indeed, the boundaries blur quite quickly, particularly between prerenal and renal causes. Based on the AKI pathophysiology, it can be etiologically divided into decreased renal perfusion, postrenal obstruction and kidney specific injury or unspecific injury. AKI is a common event in hospitalized patients and associates strongly with mortality and chronic kidney disease (CKD). Today it is accepted that AKI and CKD are rather an individually variable continuum, than 2 distinct entities. If AKI has not regressed after 7 days, it is referred to as acute kidney disease (AKD). Persisting AKD for > 90 days is classified as CKD. The transition from AKD to CKD is the result of an incomplete and maladaptive repair process. Although follow-up of post-AKI patients is essential, optimal concepts still need to be developed.

Effect of Coformer Selection on In Vitro and In Vivo Performance of Adefovir Dipivoxil Cocrystals

PURPOSE

This study aimed to improve the in vitro dissolution, permeability and oral bioavailability of adefovir dipivoxil (ADD) by cocrystal technology and clarify the important role of coformer selection on the cocrystal's properties.

METHODS

ADD was cocrystallized with three small molecules (i.e., paracetamol (PA), saccharin (SAC) and nicotinamide (NIC)), respectively. The obtained ADD-PA cocrystal was characterized by DSC, TGA, PXRD and FTIR. Comparative study on dissolution rates among the three ADD cocrystals were conducted in water and pH 6.8 phosphate buffer. Besides, effects of coformers on intestinal permeability of ADD were evaluated via in vitro Caco-2 cell model and in situ single-pass intestinal perfusion model in rats. Furthermore, in vivo pharmacokinetic study of ADD cocrystals was also compared.

RESULTS

Dissolution rates of ADD cocrystals were improved with the order of ADD-SAC cocrystal > ADD-PA cocrystal > ADD-NIC cocrystal. The permeability studies on Caco-2 cell model and single-pass intestinal perfusion model indicated that PA could enhance intestinal absorption of ADD by P-gp inhibition, while SAC and NIC did not. Further in vivo pharmacokinetic study showed that ADD-SAC cocrystal exhibited higher C_max (1.4-fold) and AUC_0-t (1.3-fold) of ADD than administration of ADD alone, and C_max and AUC_0-t of ADD-PA cocrystal were significantly enhanced by 2.1-fold and 2.2-fold, respectively, which was attributed to its higher dissolution and improved intestinal permeability.

CONCLUSION

Coformer selection had an important role on cocrystal's properties, and cocrystallization of ADD with a suitable coformer was an effective approach to enhance both dissolution and bioavailability of ADD.

The effect of immunosuppression therapy on activities of daily living and comfort level after liver transplantation

OBJECTIVES

This study was carried out to investigate the effect of immunosuppression therapy on activities of daily living and comfort level after liver transplantation.

MATERIALS AND METHODS

This study was conducted in a descriptive and correlational type with the participation of 148 liver transplant patients hospitalized in the liver transplant center of a university hospital. Personal Information Form, Katz Activities of Daily Living Scale and General Comfort Questionnaire were used in data collection. The data analysis was performed with IBM SPSS (Statistical Package for the Social Sciences) Statistics 25.

RESULTS

According to the results obtained from the study, it was determined that 31.1% of the patients were 58 years old and over, 20.9% of them were between 48- and 57 years old, and 81.8% of them were male. It was found that 61.5% of the patients were between the 11th and 21st days after transplantation and 26.4% of them were given oxygen with a non-invasive catheter. It was determined that the patients were semi-independent in activities of daily living and had a moderate comfort level.

CONCLUSIONS

It is not always possible for liver transplant patients to effectively deal with their condition. The low comfort level and quality of life of patients who have undergone liver transplantation should be noticed, and social, economic and psychological support should be provided.

Metabolic and Lipidomic Assessment of Kidney Cells Exposed to Nephrotoxic Vancomycin Dosages

Vancomycin is a glycopeptide antibiotic used against multi-drug resistant gram-positive bacteria such as Staphylococcus aureus (MRSA). Although invaluable against resistant bacteria, vancomycin harbors adverse drug reactions including cytopenia, ototoxicity, as well as nephrotoxicity. Since nephrotoxicity is a rarely occurring side effect, its mechanism is incompletely understood. Only recently, the actual clinically relevant concentration the in kidneys of patients receiving vancomycin was investigated and were found to exceed plasma concentrations by far. We applied these clinically relevant vancomycin concentrations to murine and canine renal epithelial cell lines and assessed metabolic and lipidomic alterations by untargeted and targeted gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry analyses. Despite marked differences in the lipidome, both cell lines increased anabolic glucose reactions, resulting in higher sorbitol and lactate levels. To the best of our knowledge, this is the first endometabolic profiling of kidney cells exposed to clinically relevant vancomycin concentrations. The presented study will provide a valuable dataset to nephrotoxicity researchers and might add to unveiling the nephrotoxic mechanism of vancomycin.

Dupilumab in Adults with Moderate-to-Severe Atopic Dermatitis and Prior Use of Systemic Non-Steroidal Immunosuppressants: Analysis of Four Phase 3 Trials

INTRODUCTION

Dupilumab is approved as first-line systemic treatment for adults/adolescents with moderate-to-severe atopic dermatitis (AD) in Europe and elsewhere owing to its favourable benefit-risk profile. However, systemic non-steroidal immunosuppressants (NSISS) are often used as first-line therapy in clinical practice. Impact of prior therapy with NSISS on dupilumab's treatment effect vs. control has not been described previously. This study assessed dupilumab's efficacy vs. control in patients with moderate-to-severe AD, comparing treatment effect in patients with/without prior systemic NSISS therapy, in four phase 3 trials.

METHODS

This post hoc analysis included 1553 patients randomized to placebo or dupilumab (300 mg q2w) as monotherapy for 16 weeks, or with concomitant topical corticosteroids (TCS) for 16/52 weeks, from four randomized, double-blind, placebo-controlled, phase 3 trials. Patients were stratified by prior use of systemic NSISS and dupilumab-treated patients were analysed against control groups (treated with placebo or placebo + TCS).

RESULTS

Dupilumab-treated patients, regardless of prior treatment with NSISS, achieved a significantly higher percentage reduction from baseline in Eczema Area and Severity Index (EASI), SCORing Atopic Dermatitis (SCORAD), Dermatology life Quality Index (DLQI), and Patient-Oriented Eczema Measure (POEM) vs. control; significantly more achieved EASI score ≤ 7, Peak Pruritus Numerical Rating Scale ≤ 4, POEM ≤ 7, and DLQI ≤ 5 by week 4. These rapid, significant improvements were seen with or without concomitant TCS and sustained through end-of-treatment.

CONCLUSIONS

Dupilumab treatment (monotherapy or + TCS) provides rapid, significant, sustained improvements in signs, symptoms, and quality of life in patients with moderate-to-severe AD compared with control, regardless of prior systemic NSISS use.

CLINICAL TRIAL REGISTRATION

LIBERTY AD SOLO 1: ClinicalTrials.gov identifier NCT02277743, EudraCT 2014-001198-15. LIBERTY AD SOLO 2: ClinicalTrials.gov identifier NCT02277769, EudraCT 2014-002619-40.

LIBERTY AD CHRONOS

ClinicalTrials.gov identifier NCT02260986, EudraCT 2013-003254-24. LIBERTY AD CAFÉ: ClinicalTrials.gov identifier NCT02755649, EudraCT 2015-002653-35.

Chronic renal comorbidities in pyoderma gangrenosum: a retrospective cohort study

The coexistence of pyoderma gangrenosum (PG) and chronic renal comorbidities has been reported anecdotally. We aimed to assess the bidirectional association between PG and the following chronic renal comorbidities: chronic renal failure (CRF), dialysis, kidney transplantation (KT), and other kidney diseases (OKD). That is to evaluate (i) the risk of the aforementioned diseases among patients with PG (ii) and the odds of PG after a diagnosis of renal comorbidities. A population-based retrospective cohort study was conducted comparing PG patients (n=302) with age-, sex-, and ethnicity-matched control subjects (n=1497) with regard to incident cases of renal comorbidities. A case-control design was additionally adopted to estimate the odds of PG in those with a preexisting history of renal comorbidities. Adjusted hazard ratios (HRs) and adjusted odds ratios (ORs) were estimated by Cox regression and logistic regression, respectively. Patients with PG demonstrated an increased risk of CRF (adjusted HR, 3.68; 95% CI, 2.72-5.97), dialysis (adjusted HR, 27.79; 95% CI, 3.24-238.14), and OKD (adjusted HR, 2.71; 95% CI, 1.55-4.74). In addition, the odds of PG were increased after the diagnosis of CRF (adjusted OR, 2.34; 95% CI, 1.33-4.11), KT (adjusted OR, 5.03; 95% CI, 1.01-25.12), and OKD (adjusted OR, 1.69; 95% CI, 1.04-2.74). Patients with a dual diagnosis of PG and renal diseases presented with PG at an older age and had a higher prevalence of comorbid conditions. In conclusion, a bidirectional association exists between PG and chronic renal conditions. Awareness of this comorbidity may be of benefit for physicians managing patients with PG.

Mechanism and reversal of drug-induced nephrotoxicity on a chip

The kidney plays a critical role in fluid homeostasis, glucose control, and drug excretion. Loss of kidney function due to drug-induced nephrotoxicity affects over 20% of the adult population. The kidney proximal tubule is a complex vascularized structure that is particularly vulnerable to drug-induced nephrotoxicity. Here, we introduce a model of vascularized human kidney spheroids with integrated tissue-embedded microsensors for oxygen, glucose, lactate, and glutamine, providing real-time assessment of cellular metabolism. Our model shows that both the immunosuppressive drug cyclosporine and the anticancer drug cisplatin disrupt proximal tubule polarity at subtoxic concentrations, leading to glucose accumulation and lipotoxicity. Impeding glucose reabsorption using glucose transport inhibitors blocked cyclosporine and cisplatin toxicity by 1000- to 3-fold, respectively. Retrospective study of 247 patients who were diagnosed with kidney damage receiving cyclosporine or cisplatin in combination with the sodium-glucose cotransporter-2 (SGLT2) inhibitor empagliflozin showed significant (P < 0.001) improvement of kidney function, as well as reduction in creatinine and uric acid, markers of kidney damage. These results demonstrate the potential of sensor-integrated kidney-on-chip platforms to elucidate mechanisms of action and rapidly reformulate effective therapeutic solutions, increasing drug safety and reducing the cost of clinical and commercial failures.

Drug delivery formulation impacts cyclosporine efficacy in a humanised mouse model of acute graft versus host disease

Acute graft versus host disease (aGvHD) is an allogeneic T cell mediated disease which manifests as a severe inflammatory disease affecting multiple organs including the liver, skin, lungs and gastrointestinal tract. Existing prophylactic and therapeutic approaches in aGvHD include the use of cyclosporine A (CyA), however the currently approved CyA formulations which were designed to optimise systemic CyA bioavailability can have a number of side effects including nephrotoxicity as well as the potential to attenuate the beneficial Graft-versus-Leukemia (GvL) effect. An added complication with CyA is that it has a narrow therapeutic window, and following oral administration is absorbed only from the small intestine, with variable cytochrome P450 metabolism contributing to intra- and inter-patient variability. This study sought to investigate the efficacy of a novel CyA oral formulation enabled by the integrated SmPill® oral drug delivery platform in a humanised mouse model of aGvHD. The study compared the approved optimised CyA (Neoral®) with SmPill®-enabled CyA and a systemic intravenous CyA formulation. Our findings clearly demonstrate superior efficacy of the novel SmPill® CyA in prolonging survival in a clinically relevant humanised aGvHD model. SmPill® CyA significantly reduced pathological score in the small intestine, colon, liver and lung of aGvHD mice. In addition, SmPill® CyA significantly reduced the levels of pro-inflammatory cytokines in all the GvHD target tissues examined. Notably, SmPill® CyA was significantly more potent in reducing GvHD associated pathology and inflammatory cytokine production compared to the optimised approved oral CyA formulation, Neoral®.

Combination therapy of phosphatidylserine liposome with cyclosporine A improves nephrotoxicity and attenuates delayed-type hypersensitivity response

This study aimed to evaluate the antioxidant capacity of phosphatidylserine liposome (PS) against oxidative stress due to cyclosporine A (CsA) and concurrent administration of PS and CsA on the attenuation of immune response. The effect of oral PS was evaluated on biochemical and oxidative renal markers and histopathology of nephrotic rats receiving CsA. The effect of co-administration of PS with CsA was also assessed on DTH (delayed-type hypersensitivity) reaction of immunized rats. The cytokines production level of IL-2 (Interleukin-2) and IFN-γ (Interferon gamma) was measured in immunized rat's splenocytes. PS treatment significantly (P < 0.05) reduced Cr and BUN of serum and MDA (malondialdehyde) in kidney tissue, and increased SOD (superoxide dismutase) and CAT (Catalase) of kidney tissue in CsA-nephrotic rats. Histopathology data indicated significantly (P < 0.05) nephrotoxicity improvement after 25-day treatment with PS. Furthermore, CsA plus PS administration significantly reduced DTH response and cytokines production of IL-2 and IFN-γ in immunized rats. In conclusion, coadministration of CsA plus PS may overcome oxidative stress and improve the performance of organ transplantation or autoimmune therapy.

Biopsy-Controlled Non-Invasive Quantification of Collagen Type VI in Kidney Transplant Recipients: A Post-Hoc Analysis of the MECANO Trial

The PRO-C6 assay, a reflection of collagen type VI synthesis, has been proposed as a non-invasive early biomarker of kidney fibrosis. We aimed to investigate cross-sectional and longitudinal associations between plasma and urine PRO-C6 and proven histological changes after kidney transplantation. The current study is a post-hoc analysis of 94 participants of the MECANO trial, a 24-month prospective, multicenter, open-label, randomized, controlled trial aimed at comparing everolimus-based vs. cyclosporine-based immunosuppression. PRO-C6 was measured in plasma and urine samples collected 6 and 24 months post-transplantation. Fibrosis was evaluated in biopsies collected at the same time points by Banff interstitial fibrosis/tubular atrophy (IF/TA) scoring and collagen staining (Picro Sirius Red; PSR); inflammation was evaluated by the tubulo-interstitial inflammation score (ti-score). Linear regression analyses were performed. Six-month plasma PRO-C6 was cross-sectionally associated with IF/TA score (Std. β = 0.34), and prospectively with 24-month IF/TA score and ti-score (Std. β = 0.24 and 0.23, respectively) (p < 0.05 for all). No significant associations were found between urine PRO-C6 and any of the biopsy findings. Fibrotic changes and urine PRO-C6 behaved differentially over time according to immunosuppressive therapy. These results are a first step towards non-invasive fibrosis detection after kidney transplantation by means of collagen VI synthesis measurement, and further research is required.

Cilastatin as a protective agent against drug-induced nephrotoxicity: a literature review

INTRODUCTION

Cilastatin, a dehydropeptidase I inhibitor, has been used alongside imipenem, a broad spectrum antibiotic, in order to reduce its renal metabolism, consequently increasing its urinary recovery and effectiveness for many years. However, this measure could be useful in preventing imipenem-induced renal damage and decreasing the number of nephrotoxicity reports with imipenem. In this review, the authors gathered all available studies focusing on cilastatin use as a nephroprotective agent, beside well-known nephrotoxic medications like vancomycin, cisplatin, cyclosporine, or tacrolimus.

AREAS COVERED

PubMed, Scopus, Google Scholar, and Medline databases were searched using key words like 'cilastatin,' 'nephroprotective,' 'nephroprotection,' 'vancomycin,' 'nephrotoxicity,' 'cisplatin,' 'cyclosporine,' 'tacrolimus,' and 'prevention' with varying combinations. All relevant animal and human studies up to the date of publication were included.

EXPERT OPINION

It seems that cilastatin could potentially be effective against drug-induced nephrotoxicity via mechanisms such as reducing reactive oxygen species (ROS) production, apoptosis, P-glycoprotein suppression, and morphological changes of renal cells. Nearly all the in vitro, in vivo and human studies have supported this hypothesis. Though since cilastatin protective effect has not extensively been researched in humans, its efficacy and widespread use with other nephrotoxic agents is yet to be defined in large well-designed human studies.

Selected Biochemical Parameters in Children of Mothers After Kidney Transplantation

INTRODUCTION

The number of pregnant kidney graft recipients receiving immunosuppressive drugs is increasing yearly. All potentially nephrotoxic and hepatotoxic immunosuppressive drugs penetrate through the placenta, which raises questions about their long-term effects on offspring.

OBJECTIVES

The study aimed to evaluate the influence of immunosuppressive drugs used by pregnant women after kidney transplantation on the biochemical parameters of their children.

MATERIALS AND METHODS

Forty children born to mothers after kidney transplantation (KTx) and 40 children of healthy mothers from the control group were included in the study. All graft-recipient mothers received immunosuppressive treatment during pregnancy. The study compared biochemical parameters, including urea, creatinine, potassium, and sodium, in both groups.

RESULTS

Elevated creatinine level was observed in 1 newborn in the KTx group and none of the children from the control group (P = .500). All KTx children had normal urea levels, while in the control group, 2 newborns had an increased level of urea (P = .247). Elevated potassium levels were observed in 10% of children in the KTx group and 20% of children in the control group (χ² = 0.881; P = .348). Elevated sodium levels were observed in 22.5% of children in the KTx group and 32.5% of children in the control group (χ² = 1.001; P =.317). No child in the KTx group had hyponatremia; mild hyponatremia was observed in 5% of children in the control group (P = .247).

CONCLUSION

There was no increased risk of an abnormal concentration of urea, creatinine, sodium, and potassium in the offspring of mothers after kidney transplantation using immunosuppressive drugs during pregnancy.

Serial Quantification of Urinary Protein Biomarkers to Predict Drug-induced Acute Kidney Injury

BACKGROUND

Drug-induced Acute Kidney Injury (AKI) develops in 10-15% of patients who receive nephrotoxic medications. Urinary biomarkers of renal tubular dysfunction may detect nephrotoxicity early and predict AKI.

METHODS

We prospectively studied patients who received aminoglycosides, vancomycin, amphotericin, or calcineurin inhibitors, and collected their serial urine while on therapy. Patients who developed drug-induced AKI (fulfilling KDIGO criteria) were matched with non-AKI controls in a 1:2 ratio. Their urine samples were batch-analyzed at time-intervals leading up to AKI onset; the latter benchmarked against the final day of nephrotoxic therapy in non- AKI controls. Biomarkers examined include clusterin, beta-2-microglobulin, KIM1, MCP1, cystatin-C, trefoil-factor- 3, NGAL, interleukin-18, GST-Pi, calbindin, and osteopontin; biomarkers were normalized with corresponding urine creatinine.

RESULTS

Nine of 84 (11%) patients developed drug-induced AKI. Biomarkers from 7 AKI cases with pre-AKI samples were compared with those from 14 non-AKI controls. Corresponding mean ages were 55(±17) and 52(±16) years; baseline eGFR were 99(±21) and 101(±24) mL/min/1.73m2 (all p=NS). Most biomarker levels peaked before the onset of AKI. Median levels of 5 biomarkers were significantly higher in AKI cases than controls at 1-3 days before AKI onset (all µg/mmol): clusterin [58(8-411) versus 7(3-17)], beta-2-microglobulin [1632(913-3823) versus 253(61-791)], KIM1 [0.16(0.13-0.76) versus 0.07(0.05-0.15)], MCP1 [0.40(0.16-1.90) versus 0.07(0.04-0.17)], and cystatin-C [33(27-2990) versus 11(7-19)], all p<0.05; their AUROC for AKI prediction were >0.80 (confidence intervals >0.50), with average accuracy highest for clusterin (86%), followed by beta-2-microglobulin, cystatin-C, MCP1, and KIM1 (57%) after cross-validation.

CONCLUSION

Serial surveillance of these biomarkers could improve the lead time for nephrotoxicity detection by days.

Hydrogen-rich water alleviates cyclosporine A-induced nephrotoxicity via the Keap1/Nrf2 signaling pathway

Oxidative stress induced by long-term cyclosporine A (CsA) administration is a major cause of chronic nephrotoxicity, which is characterized by tubular atrophy, tubular cell apoptosis, and interstitial fibrosis in the progression of organ transplantation. Although hydrogen-rich water (HRW) has been used to prevent various oxidative stress-related diseases, its underlying mechanisms remain unclear. This study investigated the effects of HRW on CsA-induced nephrotoxicity and its potential mechanisms. After administration of CsA (25 mg/kg/day), rats were treated with or without HRW (12 mL/kg) for 4 weeks. Renal function and vascular activity were investigated. Histological changes in kidney tissues were analyzed using Masson's trichrome and terminal deoxynucleotidyl transferase dUTP nick-end labeling stains. Oxidative stress markers and the activation of the Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway were also measured. We found that CsA increased the levels of reactive oxygen species (ROS) and malonaldehyde (MDA), but it reduced glutathione (GSH) and superoxide dismutase (SOD) levels. Such alterations induced vascular dysfunction, tubular atrophy, interstitial fibrosis, and tubular apoptosis. This was evident secondary to an increase in urinary protein, serum creatinine, and blood urea nitrogen, ultimately leading to renal dysfunction. Conversely, HRW decreased levels of ROS and MDA while increasing the activity of GSH and SOD. This was accompanied by an improvement in vascular and renal function. Moreover, HRW significantly decreased the level of Keap1 and increased the expression of Nrf2, NADPH dehydrogenase quinone 1, and heme oxygenase 1. In conclusion, HRW restored the balance of redox status, suppressed oxidative stress damage, and improved kidney function induced by CsA via activation of the Keap1/Nrf2 signaling pathway.

The Effect of Sertoli Cells on Xenotransplantation and Allotransplantation of Ventral Mesencephalic Tissue in a Rat Model of Parkinson's Disease

Intra-striatal transplantation of fetal ventral mesencephalic (VM) tissue has a therapeutic effect on patients with Parkinson’s disease (PD). Sertoli cells (SCs) possess immune-modulatory properties that benefit transplantation. We hypothesized that co-graft of SCs with VM tissue can attenuate rejection. Hemi-parkinsonian rats were generated by injecting 6-hydroxydopamine into the right medial forebrain bundle of Sprague Dawley (SD) rats. The rats were then intrastriatally transplanted with VM tissue from rats or pigs (rVM or pVM), with/without a co-graft of SCs (rVM+SCs or pVM+SCs). Recovery of dopaminergic function and survival of the grafts were evaluated using the apomorphine-induced rotation test and small animal-positron emission tomography (PET) coupled with [¹⁸F] DOPA or [¹⁸F] FE-PE2I, respectively. Immunohistochemistry (IHC) examination was used to determine the survival of the grafted dopaminergic neurons in the striatum and to investigate immune-modulatory effects of SCs. The results showed that the rVM+SCs and pVM+SCs groups had significantly improved drug-induced rotational behavior compared with the VM alone groups. PET revealed a significant increase in specific uptake ratios (SURs) of [¹⁸F] DOPA and [¹⁸F] FE-PE2I in the grafted striatum of the rVM+SCs and pVM+SCs groups as compared to that of the rVM and pVM groups. SC and VM tissue co-graft led to better dopaminergic (DA) cell survival. The co-grafted groups exhibited lower populations of T-cells and activated microglia compared to the groups without SCs. Our results suggest that co-graft of SCs benefit both xeno- and allo-transplantation of VM tissue in a PD rat model. Use of SCs enhanced the survival of the grafted dopaminergic neurons and improved functional recovery. The enhancement may in part be attributable to the immune-modulatory properties of SCs. In addition, [¹⁸F]DOPA and [¹⁸F]FE-PE2I coupled with PET may provide a feasible method for in vivo evaluation of the functional integrity of the grafted DA cell in parkinsonian rats.

Kidney-based in vitro models for drug-induced toxicity testing

The kidney is frequently involved in adverse effects caused by exposure to foreign compounds, including drugs. An early prediction of those effects is crucial for allowing novel, safe drugs entering the market. Yet, in current pharmacotherapy, drug-induced nephrotoxicity accounts for up to 25% of the reported serious adverse effects, of which one-third is attributed to antimicrobials use. Adverse drug effects can be due to direct toxicity, for instance as a result of kidney-specific determinants, or indirectly by, e.g., vascular effects or crystals deposition. Currently used in vitro assays do not adequately predict in vivo observed effects, predominantly due to an inadequate preservation of the organs' microenvironment in the models applied. The kidney is highly complex, composed of a filter unit and a tubular segment, together containing over 20 different cell types. The tubular epithelium is highly polarized, and the maintenance of this polarity is critical for optimal functioning and response to environmental signals. Cell polarity is dependent on communication between cells, which includes paracrine and autocrine signals, as well as biomechanic and chemotactic processes. These processes all influence kidney cell proliferation, migration, and differentiation. For drug disposition studies, this microenvironment is essential for prediction of toxic responses. This review provides an overview of drug-induced injuries to the kidney, details on relevant and translational biomarkers, and advances in 3D cultures of human renal cells, including organoids and kidney-on-a-chip platforms.

The Neuropeptide Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) is Protective in Inflammation and Oxidative Stress-Induced Damage in the Kidney

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a pleiotropic neuropeptide with a widespread distribution throughout the entire body including the urinary system. PACAP exerts protective actions in different injury models related to several organ systems. Its protective effect is mainly based on its antiapoptotic, anti-inflammatory and antioxidant effects. The present review aims to summarize the effects of PACAP in pathologies associated with inflammation and oxidative stress-induced damage in the kidney. Both in vitro and in vivo data are available proving its protective actions against oxidative stress, hypoxia, renal ischemia/reperfusion, diabetic nephropathy, myeloma kidney injury, amyloidosis and different types of drug-induced nephropathies. Data showing the nephroprotection by PACAP emphasize the potential of PACAP’s therapeutic use in various renal pathologies.

Immunosuppression following organ transplantation. Part 2: complications and their management

Advances in the care of patients who have had a solid organ transplant has led to a growing population of post-transplant patients, who are also living for longer. As a result of their longer life expectancy, transplant recipients often face a multitude of challenges, including optimising their immunosuppressive regimens and managing potential complications. Life-threatening infections, malignancies, and organ-specific toxicities are the complications post-transplant patients commonly encounter and these complications are often associated with increased morbidity and mortality, adverse graft functioning and survival, profound impairment in the patient's quality of life, and significant healthcare burden. This article, the second of two parts, gives an overview of the issues involved in the care of patients who are receiving immunosuppressants. The common complications encountered by post-transplant patients are discussed and their assessment, management, prevention and treatment explored.

Further enhanced dissolution and oral bioavailability of docetaxel by coamorphization with a natural P-gp inhibitor myricetin

The current study aims to improve the dissolution and oral bioavailability of a BCS IV drug docetaxel (DOC) by coamorphization with a natural P-gp inhibitor myricetin (MYR). A single-phase coamorphous form of DOC with MYR in a 1:1 molar ratio was prepared by solvent-evaporation method and characterized by differential scanning calorimetry, thermogravimetric analysis and powder X-ray diffraction. In comparison to crystalline DOC, amorphous DOC showed similar equilibrium aqueous solubility, temporary improvement in the intrinsic dissolution rate (IDR) and supersaturated dissolution; while coamorphous DOC-MYR exhibited a persistent enhanced IDR and prolonged highly supersaturated dissolution. In addition, coamorphous DOC-MYR demonstrated significantly superior physical stability compared to amorphous DOC under the long-term storage condition and accelerated condition. Compared with oral administration of crystalline DOC to rats, amorphous DOC showed a significant increase in C_max (2.6-fold) and a marginal increase in AUC (1.3-fold) of DOC; but coamorphous DOC-MYR performed a 3.9-fold higher C_max and 3.1-fold higher AUC. In conclusion, coamorphization of DOC with MYR was a promising approach to enhance both dissolution and oral absorption of poorly soluble and permeable DOC.

Messengers of tolerance

The use of immunosuppressant drugs after organ transplantation has brought great success in the field of organ transplantation with respect to short-term outcome. However, major challenges (i.e., limited improvement of long-term survival, immunosuppressant toxicity, infections and carcinoma) demand alternate treatment approaches that minimizes the use of immunosuppressants. Interestingly, few studies have identified groups of transplant patients who developed operational tolerance and thereby keep their allograft without complications in absence of immunosuppressants. These rare groups of patients are of particular interest as study subjects for understanding mechanisms of graft tolerance that could be leveraged in future for inducing tolerance and for understanding mechanisms involved in improving long-term allograft outcomes. Also, biomarkers from these studies could benefit the larger transplant population by their application in immunosuppressant tailoring and identification of tolerant patients among patients with stably functioning allografts. This review compiles several gene expression studies performed in samples from tolerant patients in different solid organ transplantations to identify key genes and associated molecular pathways relevant to tolerance. This review is aimed at putting forth all this important work done thus far and to identify research gaps that need to be filled, in order to achieve the greater purpose of these studies.

Clinicopathologic Impact of Early Medullary Ray Injury in Patients Following Kidney Transplantation

BACKGROUND

Previously, we explored the histopathologic characteristics of medullary ray injury (MRI) inducing interstitial fibrosis and tubular atrophy (IF/TA) to determine its etiologies, which include calcineurin inhibitor (CNI) toxicity and urologic complications. However, we did not examine the effects of these etiologies on long-term kidney allograft prognosis, because biopsy timing differed among cases.

AIM

We examined the influence of early MRI on kidney allograft prognosis using protocol biopsies taken within a 3-month time frame.

METHODS

We defined early MRI as tubular degeneration with interstitial edema or mild fibrosis localized to the medullary ray. We divided 53 protocol biopsies into 2 groups, with and without early MRI. Early MRI+ cases with isometric vacuolization were classified as CNI toxicity; those with Tamm-Horsfall protein in the interstitium and a thyroidlike appearance were classified as urinary tract system abnormalities; remaining cases were classified as "others." We compared changes in serum levels of creatinine (sCr) over 3 years and fibrosis extent at 1 year.

RESULTS

The sCr levels were significantly higher in the MRI+ group than the MRI- group at 3 years (P = .024). Examining the 3 MRI+ subgroups, only the MRI+ urinary tract system abnormalities group had significantly high sCr levels compared to the MRI- group (P = .019). The MRI+ group showed significant signs of IF/TA at 1 year.

CONCLUSIONS

Early MRI after kidney transplantation was significantly more likely to develop IF/TA at 1 year and had higher sCr levels at 3 years. In such cases, intervention might preserve graft function over the long term.

Protective Effect of Edaravone Against Cyclosporine-Induced Chronic Nephropathy Through Antioxidant and Nitric Oxide Modulating Pathways in Rats

BACKGROUND

Cyclosporine A (CsA) is an immunosuppressant with therapeutic indications in various immunological diseases; however, its use is associated with chronic nephropathy. Oxidative stress has a crucial role in CsA-induced nephrotoxicity. The present study evaluates the protective effect of edaravone on CsA-induced chronic nephropathy and investigates its antioxidant and nitric oxide modulating property.

METHODS

Male Sprague-Dawley rats (n=66) were distributed into nine groups, including a control (group 1) (n=7). Eight groups received CsA (15 mg/kg) for 28 days while being treated. The groups were categorized as: Group 2: Vehicle (n=10)Groups 3, 4, and 5: Edaravone (1, 5, and 10 mg/kg) (n=7 each)Group 6: Diphenyliodonium chloride, a specific endothelial nitric oxide synthase (eNOS) inhibitor (n=7)Group 7: Aminoguanidine, a specific inducible nitric oxide synthase (iNOS) inhibitor (n=7)Group 8: Edaravone (10 mg/kg) plus diphenyliodonium chloride (n=7)Group 9: Edaravone (10 mg/kg) plus aminoguanidine (n=7) Blood urea nitrogen and serum creatinine levels, malondialdehyde, superoxide dismutase, and glutathione reductase enzyme activities were measured using standard kits. Renal histopathological evaluations and measurements of eNOS and iNOS gene expressions by RT-PCR were also performed. Data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's test (SPSS software version 18.0).

RESULTS

Edaravone (10 mg/kg) significantly attenuated CsA-induced oxidative stress, renal dysfunction, and kidney tissue injury. Aminoguanidine improved the renoprotective effect of edaravone. Edaravone reduced the elevated mRNA level of iNOS, but could not alter the level of eNOS mRNA significantly.

CONCLUSION

Edaravone protects against CsA-induced chronic nephropathy using antioxidant property and probably through inhibiting iNOS gene expression.

Interstitial Lung Disease After Kidney Transplantation and the Role of Everolimus

BACKGROUND

Kidney transplant recipients are at higher risk of developing pulmonary complications related to immunosuppression, and inhibitor of the mammalian target of rapamycin (mTORi) has been reported as a potential cause.

METHODS

Five hundred kidney-transplanted patients were retrospectively analyzed for pulmonary complications on the basis of clinical and instrumental data (chest radiography, high-resolution computed tomography, broncho-alveolar lavage, oximetry).

RESULTS

We found 26 interstitial lung diseases (ILD) (16%): 12 cases (46.2%) were from infections (42.8% by Pneumocystis jirovecii) and 14 cases of ILD (53.8%) resulted as drug-induced ILD (DI-ILD). According to anti-rejection protocols, DI-ILD occurred in 8 patients (57%) while on triple regimen including steroids, everolimus (EVL), and cyclosporine (CyA) and in 6 patients on double regimen with steroids and mTORi: EVL or sirolimus (43%). In ILD+ patients, everolimus trough-concentration (EVL(TLC)) and cyclosporine (2nd-hour concentration: CyA(C2)) levels were higher than in patients in the same regimen but with ILD- (EVL(TLC) [ng/mL] 9.84 versus 6.85; CyA(C2) [ng/mL] 303.97 versus 298.56). The formula that used the combined blood levels of both drugs (EVL(TLC) + CyA(C2)/100) resulted in a significant difference between groups of patients (12.88 ± 1.61 versus 9.83 ± 1.91). Applying receiver operator characteristic curve (ROC) analysis to detect risk of developing ILD when on combined protocol with EVL and CyA, we obtained an area under the curve of 0.8622 (P = .0081) and 0.9082 (P = .0028), respectively, when using EVL(TLC) or the combination formula with both drugs.

CONCLUSIONS

In renal transplant patients, we obtained a relationship of ILD to specific drug concentration. On the basis of ROC analysis, patients on EVL and CyA combined protocol are at risk of ILD when EVL(TLC) is >9.03 ng/mL or >11.41 when a formula with summation of EVL(TLC) and CyA(C2) is used.

TMBIM6 (transmembrane BAX inhibitor motif containing 6) enhances autophagy and reduces renal dysfunction in a cyclosporine A-induced nephrotoxicity model

Cyclosporine A (CsA) is widely used as an immunosuppressor in transplantation. Previous studies reported that CsA induces autophagy and that chronic treatment with CsA results in accumulation of autophagosomes and reduced autophagic clearance. Autophagy is a prosurvival process that promotes recovery from acute kidney injury by degrading misfolded proteins produced in the kidney. In the present study, we used TMBIM6-expressing HK-2, human kidney tubular cells (TMBIM6 cells) and Tmbim6 knockout (tmbim6(-/-)) mice. When exposed to CsA, the TMBIM6 cells maintained autophagy activity by preventing autophagosome accumulation. With regard to signaling, PRKKA/AMPK phosphorylation and mechanistic target of rapamycin (serine/threonine kinase) complex 1 (MTORC1) expression and its downstream target TFEB (transcription factor EB), a lysosome biogenesis factor, were regulated in the TMBIM6 cells. Lysosomal activity was highly increased or stably maintained in the presence of TMBIM6. In addition, treatment of tmbim6(-/-) mice with CsA resulted in increased autophagosome formation and decreased lysosome formation and activity. We also found that tmbim6(-/-) mice were susceptible to CsA-induced kidney injury. Taken together, these results indicate that TMBIM6 protects against CsA-induced nephrotoxicity both in vitro and in vivo by inducing autophagy and activating lysosomes.

Molecular and clinical aspects of drug-induced gingival overgrowth

Drug-induced gingival overgrowth is a tissue-specific condition and is estimated to affect approximately one million North Americans. Lesions occur principally as side-effects from phenytoin, nifedipine, or ciclosporin therapy in approximately half of the people who take these agents. Due to new indications for these drugs, their use continues to grow. Here, we review the molecular and cellular characteristics of human gingival overgrowth lesions and highlight how they differ considerably as a function of the causative drug. Analyses of molecular signaling pathways in cultured human gingival fibroblasts have provided evidence for their unique aspects compared with fibroblasts from the lung and kidney. These findings provide insights into both the basis for tissue specificity and into possible therapeutic opportunities which are reviewed here. Although ciclosporin-induced gingival overgrowth lesions exhibit principally the presence of inflammation and little fibrosis, nifedipine- and especially phenytoin-induced lesions are highly fibrotic. The increased expression of markers of gingival fibrosis, particularly CCN2 [also known as connective tissue growth factor (CTGF)], markers of epithelial to mesenchymal transition, and more recently periostin and members of the lysyl oxidase family of enzymes have been documented in phenytoin or nifedipine lesions. Some oral fibrotic conditions such as leukoplakia and oral submucous fibrosis, after subsequent additional genetic damage, can develop into oral cancer. Since many pathways are shared, the study of gingival fibrosis and comparisons with characteristics and molecular drivers of oral cancer would likely enhance understandings and functional roles of molecular drivers of these oral pathologies.

ER-mitochondrial calcium flow underlies vulnerability of mechanosensory hair cells to damage

Mechanosensory hair cells are vulnerable to environmental insult, resulting in hearing and balance disorders. We demonstrate that directional compartmental flow of intracellular Ca(2+) underlies death in zebrafish lateral line hair cells after exposure to aminoglycoside antibiotics, a well characterized hair cell toxin. Ca(2+) is mobilized from the ER and transferred to mitochondria via IP3 channels with little cytoplasmic leakage. Pharmacological agents that shunt ER-derived Ca(2+) directly to cytoplasm mitigate toxicity, indicating that high cytoplasmic Ca(2+) levels alone are not cytotoxic. Inhibition of the mitochondrial transition pore sensitizes hair cells to the toxic effects of aminoglycosides, contrasting with current models of excitotoxicity. Hair cells display efficient ER-mitochondrial Ca(2+) flow, suggesting that tight coupling of these organelles drives mitochondrial activity under physiological conditions at the cost of increased susceptibility to toxins.

Mycophenolic acid affects basic functions of human keratinocytes in the IMPDH-dependent manner

Clinical studies suggest that the immunosuppressant MPA is associated with impaired wound healing. It is believed that the main cause of impairment is the inhibition of inflammatory response. However, it is unknown whether MPA may directly affect epidermal cells. The aim of our study was to examine the direct influence of mycophenolic acid, the selective blocker of de novo purine synthesis, on human epidermal keratinocyte morphology, proliferation, motile activity, and differentiation in in vitro culture. The number of keratinocytes cultured in the presence of MPA was counted and cell motility was measured by a time-lapse computer-aided method. Cell morphology was determined by flow and image cytometry methods. Real-time RT-PCR analysis was employed to investigate the expression of markers of differentiation. We showed that MPA induces irreversible inhibition of cell proliferation, causes cell enlargement and impairs cell locomotion in a time-dependent manner. The level of expression of differentiation markers was significantly reduced by MPA treatment. All these effects were reversed by the addition of guanine. Our results indicated that MPA impairs basic functions of human skin keratinocytes via intracellular guanosine nucleotide depletion, which may be directly reflected in wound healing problems in patients treated with this immunosuppressant.

Sildenafil protects against nitric oxide deficiency-related nephrotoxicity in cyclosporine A treated rats

Cyclosporine A (CsA) is the most widely used immunosuppressant in organ transplant surgery and in treatment of autoimmune disease. Nevertheless, animal and clinical studies have demonstrated that nephrotoxicity is the major adverse effect limiting the prolonged CsA therapeutic use. The present study aimed to investigate possible protective effect of sildenafil, a phoshodiestrase-5 inhibitor, on CsA-induced nephrotoxicity and various mechanism(s) underlies this effect. Male Wistar rats were administered CsA (20 mg/kg/day, s.c.) for 21 days alone or in combination with sildenafil (5 mg/kg/day, p.o.). Sildenafil exhibited nephroprotective effects as evidenced by significant decrease in serum creatinine and urea levels, spot urine albumin-creatinine ratio, as well as renal level of malondialdehyde, with a concurrent increase in renal levels of reduced glutathione and nitric oxide along with catalase activity compared to CsA-treated rats. [corrected]. Additionally, immunohistochemical analysis demonstrated that sildenafil treatment markedly reduced inducible nitric oxide synthase, tumor necrosis factor-alpha, and caspase-3 expressions, while expression of endothelial nitric oxide synthase was prominently enhanced. The protective effects of sildenafil were confirmed by renal histopathological examination. Pretreatment with l-nitro-arginine methyl ester (10 mg/kg/day, i.p.), a non-selective nitric oxide synthase inhibitor, reversed the protection afforded by sildenafil. Taken together, the current study highlighted the renoprotective effects of sildenafil against CsA-induced nephrotoxicity in rats, which might be mediated, in part, through nitric oxide pathway as well as antioxidant, anti-inflammatory, and anti-apoptotic activities.

Renal cortical infarction following treatment with sumatriptan in a kidney allograft recipient

Renal cortical infarction is a rare cause of acute kidney injury that results from inadequate blood flow to the kidney, most commonly as a consequence of thrombotic or embolic occlusion of the renal artery or profound hypoperfusion. We report the case of a 78-year-old female kidney transplant recipient who developed a migraine headache, took sumatriptan, and soon after developed pain over the allograft and oligoanuric acute kidney injury. Kidney allograft biopsy showed renal cortical infarction. The mechanism of action of sumatriptan involves vasoconstriction, which counters the vasodilatation that is central to the pathogenesis of migraines. This case raises important questions regarding the safety of triptans with calcineurin inhibitors (which also act to vasoconstrict), particularly in elderly patients.