Long-term Calcineurin Inhibitor Research Articles

The Role of Vitamin D Metabolism Genes and Their Genomic Background in Shaping Cyclosporine A Dosage Parameters after Kidney Transplantation.

Background: Kidney transplantation is followed by immunosuppressive therapy involving calcineurin inhibitors (CNIs) such as cyclosporin A. However, long-term high CNIs doses can lead to vitamin D deficiency, and genetic variations influencing vitamin D levels can indirectly impact the necessary CNIs dosage. This study investigates the impact of genetic variations of vitamin D binding protein (DBP) rs2282679 and CYP2R1 hydroxylase rs10741657 polymorphisms on the cyclosporin A dosage in kidney transplant recipients. Additional polymorphisims of genes that are predicted to influence the pharmacogenetic profile were included. Methods: Gene polymorphisms in 177 kidney transplant recipients were analyzed using data mining techniques, including the Random Forest algorithm and Classification and Regression Trees (C&RT). The relationship between the concentration/dose (C/D) ratio of cyclosporin A and genetic profiles was assessed to determine the predictive value of DBP rs2282679 and CYP2R1 rs10741657 polymorphisms. Results: Polymorphic variants of the DBP (rs2282679) demonstrated a strong predictive value for the cyclosporin A C/D ratio in post-kidney transplantation patients. By contrast, the CYP2R1 polymorphism (rs10741657) did not show predictive significance. Additionally, the immune response genes rs231775 CTLA4 and rs1800896 IL10 were identified as predictors of cyclosporin A response, though these did not result in statistically significant differences. Conclusions:DBP rs2282679 polymorphisms can significantly predict the cyclosporin A C/D ratio, potentially enhancing the accuracy of CNI dosing. This can help identify patient groups at risk of vitamin D deficiency, ultimately improving the management of kidney transplant recipients. Understanding these genetic influences allows for more personalized and effective treatment strategies, contributing to better long-term outcomes for patients.

Tacrolimus induces fibroblast-to-myofibroblast transition via a TGF-β-dependent mechanism to contribute to renal fibrosis.

Use of immunosuppressant calcineurin inhibitors (CNIs) is limited by irreversible kidney damage, hallmarked by renal fibrosis. CNIs directly damage many renal cell types. Given the diverse renal cell populations, additional targeted cell types and signaling mechanisms warrant further investigation. We hypothesized that fibroblasts contribute to CNI-induced renal fibrosis and propagate profibrotic effects via the transforming growth factor-β (TGF-β)/Smad signaling axis. To test this, kidney damage-resistant mice (C57BL/6) received tacrolimus (10 mg/kg) or vehicle for 21 days. Renal damage markers and signaling mediators were assessed. To investigate their role in renal damage, mouse renal fibroblasts were exposed to tacrolimus (1 nM) or vehicle for 24 h. Morphological and functional changes in addition to downstream signaling events were assessed. Tacrolimus-treated kidneys displayed evidence of renal fibrosis. Moreover, α-smooth muscle actin expression was significantly increased, suggesting the presence of fibroblast activation. TGF-β receptor activation and downstream Smad2/3 signaling were also upregulated. Consistent with in vivo findings, tacrolimus-treated renal fibroblasts displayed a phenotypic switch known as fibroblast-to-myofibroblast transition (FMT), as α-smooth muscle actin, actin stress fibers, cell motility, and collagen type IV expression were significantly increased. These findings were accompanied by concomitant induction of TGF-β signaling. Pharmacological inhibition of the downstream TGF-β effector Smad3 attenuated tacrolimus-induced phenotypic changes. Collectively, these findings suggest that 1) tacrolimus inhibits the calcineurin/nuclear factor of activated T cells axis while inducing TGF-β1 ligand secretion and receptor activation in renal fibroblasts; 2) aberrant TGF-β receptor activation stimulates Smad-mediated production of myofibroblast markers, notable features of FMT; and 3) FMT contributes to extracellular matrix expansion in tacrolimus-induced renal fibrosis. These results incorporate renal fibroblasts into the growing list of CNI-targeted cell types and identify renal FMT as a process mediated via a TGF-β-dependent mechanism.NEW & NOTEWORTHY Renal fibrosis, a detrimental feature of irreversible kidney damage, remains a sinister consequence of long-term calcineurin inhibitor (CNI) immunosuppressive therapy. Our study not only incorporates renal fibroblasts into the growing list of cell types negatively impacted by CNIs but also identifies renal fibroblast-to-myofibroblast transition as a process mediated via a TGF-β-dependent mechanism. This insight will direct future studies investigating the feasibility of inhibiting TGF-β signaling to maintain CNI-mediated immunosuppression while ultimately preserving kidney health.

Development of a mRNA Lipid Nanoparticle (mRNA-LNP) Cancer Vaccine to Prevent Leukemia Relapse after Stem Cell Transplant

Introduction The most common acute leukemia in adults is acute myeloid leukemia (AML). Approximately 20,050 new cases and 11,540 deaths are expected for 2022 in the US. Allogeneic stem cell transplant (alloSCT) remains the only cure for high-risk AML. AlloSCTs leverage the immune system to kill leukemic cells through a graft-versus-leukemia (GVL) response mediated by donor CD4+ and CD8+ T cells that recognize recipient leukemic minor histocompatibility antigens (mHAs) as foreign. Unfortunately, transplantation failure related to relapse is common. We postulate that proper targeting of mHAs could enhance leukemia-specific immune responses without off-target effects, improving relapse rates. Using computational modeling, we predicted a series of GVL mHAs, confirmed our first GVL mHA (UNC-GRK4-V) through targeted mass spectrometry, and generated a high-affinity T cell receptor (TCR) against it. Using UNC-GRK4-V as our target, we developed a novel mHA mRNA lipid nanoparticle (LNP) vaccine that we hypothesized could induce an antigen-specific immune response. Methods A custom mRNA was ordered from TriLink that encoded the UNC-GRK4-V peptide linked to an MHC Class I trafficking domain (MITD) and was modified with a 5' cap and polyadenylated tail. We created mRNA LNPs by mixing an ethanol lipid solution made of ionizable lipid (SS-OP, SM-102, or MC3)/ DOPE/Cholesterol/DMG-PEG 2000 with an aqueous solution of mRNA (eGFP or UNC-GRK4-V mRNA) dissolved in a citrated buffer solution. We measured mRNA LNP sizes with a Malvern ZS90 and quantified encapsulation rates using a Quant-it RiboGreen RNA assay kit. Immature monocyte-derived dendritic cells (mo-DCs) were differentiated from monocytes collected from fresh blood and transfected with mRNA LNPs. As a control, we measured eGFP mRNA LNP transfection rates of mo-DCs using flow cytometry. CD8+ T cells were transduced with a retroviral supernatant containing a high-affinity UNC-GRK4-V T-cell receptor and stimulated. We co-cultured mRNA LNP transfected mo-DCs with transduced CD8+ T cells. IFN-g was measured from the co-culture supernatant using IFN-g ELISA assays. We used flow cytometry to determine the cytotoxic killing of transfected mo-DCs by transduced CD8+ T cells. Results To identify the most efficient ionizable lipid platform for mRNA delivery and transfection, we tested three commercially available ionizable lipids: SS-OP, SM-102, and MC3. We found that all three ionizable lipids were easily reproducible with SS-OP 75.2nm ± SD 14.8, MC3 97.0nm ± SD 5.4, SM-102 102.1nm ± SD 0.651. The encapsulation rates of mRNA were 75.4% ± SD 6.3% for SS-OP, 70.5% ± SD 2.6% for MC3, and 73.7% ± SD 0.1% for SM-102. The transfection rate of mo-DCs using eGFP mRNA LNPs were 0.48%, 19.3%, and 62.5% for SS-OP, MC3, and SM-102, respectively. Based on poor transfection rates with SS-OP, we used MC3 and SM-102 LNP formulations to study cytokine expression and cytotoxic killing using a co-culture model of transfected mo-DC with transduced CD8+ T cells. We found a 16.8-fold increase in IFN-g release for the SM-102 based LNPs compared to control empty LNPs (p < 0.0001) and a 4.1-fold increase in IFN-g release for the MC3 based LNPs compared to control empty LNPs (p < 0.0001). We then evaluated SM-102 LNPs for cytotoxic killing as they demonstrated the highest IFN-g release. SM-102 demonstrated increased cell death of 13.5% versus 3.5% for control (empty SM-102) after being normalized for background mo-DC death. Conclusions The SM-102 based UNC-GRK4-V mRNA LNP vaccine elicits robust, antigen-specific T-cell responses and could be a potent therapeutic for decreasing relapse rates post-alloSCT. Furthermore, advances in alloSCT have created regimens that eliminate traditional long-term calcineurin inhibitor use in post-alloSCT, allowing therapeutic cancer vaccines to be given much earlier after transplant.

CD44 as a pathological marker for the early detection of calcineurin inhibitor-induced nephrotoxicity post kidney transplantation.

Long-term calcineurin inhibitor (CNI) administration causes irreversible nephrotoxicity. Therefore, early CNI-induced nephrotoxicity detection is necessary for patients who will need long-term CNI administration. There is no pathological indicator for early CNI-induced nephrotoxicity. Here, serial protocol kidney biopsy specimens from five kidney-transplant patients with severe CNI-induced nephrotoxicity were examined. We observed that the increase in CD44 expression in glomerular parietal epithelial cells (PECs) preceded the chronic pathological changes of CNI-induced nephrotoxicity such as tubular atrophy/interstitial fibrosis, arterial hyaline thickening, and focal segmental glomerulosclerosis (FSGS). This result suggests that CD44-positive PECs have pivotal roles in FSGS development in human CNI-induced nephrotoxicity as well as rodent models. CD44 could be useful as a pathological marker for early CNI-induced nephrotoxicity detection post kidney transplantation.

Selective Targeting of Calcineurin Isoforms by Calcineurin Inhibitors

Background Calcineurin inhibitors (CNIs) have increased one-year and five-year post-transplantation survival rates to ~90% and ~75%, respectively. While CNIs have dramatically improved the quality of patient care, their side effects are also noteworthy: long-term CNI therapy is nephrotoxic and is a growing concern for clinicians and patients. Research into calcineurin (CnA) activity has identified distinct actions of two main isoforms: CnAα and CnAβ. CnAα is required for kidney function, whereas CnAβ predominantly modulates the immune response. Moreover, the degree of isoform selectivity and mechanisms of CNI-induced renal impairment still remains unknown. Investigating CNI dose-dependent selective binding between catalytic isoforms will provide clues for further studies to narrow in on mechanisms by which the inhibition of calcineurin causes renal fibrosis. Objective It is well established that long-term CNI treatment causes an increase in profibrotic markers leading to renal damage. It has also been established that the most predominant catalytic isoform expressed in the kidney is CnAa. The objectives of this study are to investigate whether CNI treatment is more selective for CnAa than CnAb in the kidney, and that CnAa inhibition promotes fibrosis. Experimental Design To determine dose-dependent isoform selectivity of CNIs, wild-type mouse renal cortical fibroblasts (WT FB) were treated with varying doses of either vehicle (100% ethanol) or CNI (tacrolimus, cyclosporin) for 24 hours. Cell lysates were collected and calmodulin pull-down assays were carried out for western blot analysis to analyze expression of activated and total calcineurin isoforms. Results : CNI treatment decreases activation of calcineurin isoforms in a dose-dependent manner. Notably, there were striking differences in isoform activity with tacrolimus treatment versus cyclosporin in a dose-dependent manner. Additionally, CNIs altered expression of calcineurin isoforms and profibrotic markers. Conclusions Together, these results demonstrate that 1) isoform selectivity differs amongst each CNI and 2) inhibiting calcineurin isoforms affects total protein expression and 3) CNIs have distinct profibrotic profiles. Significance This study begins to characterize the behavior of two main active calcineurin isoforms with varying doses of CNI treatment. CNI selectivity for calcineurin isoforms directs future studies investigating molecular culprits and signaling pathways involved in CNI-induced renal damage. We expect that development of future CNIs targeting specific calcineurin isoforms will prevent kidney damage and maintain renal function with long-term CNI use.

Calcineurin inhibitors: a double-edged sword.

Recently, research has directed its interests into identifying molecular pathways implicated in calcineurin inhibitor (CNI)-induced renal fibrosis. An emerging body of studies investigating calcineurin (CnA) activity has identified distinct actions of two main ubiquitously expressed isoforms: CnAα and CnAβ. CNIs have the capacity to inhibit both of these CnA isoforms. In the kidney, CnAα is required for development, whereas CnAβ predominantly modulates the immune response and glomerular hypertrophic signaling powered by activation of the transcription factor, nuclear factor of activated T lymphocytes (NFAT). Interestingly, data have shown that loss of CnAα activity contributes to the expression of profibrotic proteins in the kidney. Although this finding is of great significance, follow-up studies are needed to identify how loss of the CnAα isoform causes progressive renal damage. In addition, it is also necessary to identify downstream mediators of CnAα signaling that assist in upregulation of these profibrotic proteins. The goal of this review is to provide insight into strides taken to close the gap in elucidating CnA isoform-specific mechanisms of CNI-induced renal fibrosis. It is with hope that these contributions will lead to the development of newer generation CNIs that effectively blunt the immune response while circumventing extensive renal damage noted with long-term CNI use.

Impact of immunosuppressive therapy on brain derived cytokines after liver transplantation

BackgroundWhile acute neurotoxic side effects of calcineurin inhibitors (CNI) are well-known, data upon long-term effects on brain structure and function are sparse. We hypothesize that long-term CNI therapy affects the neuroimmune system, thereby, increasing the risk of neurodegeneration. Here, we measured the impact of CNI therapy on plasma levels of brain- and T cell-derived cytokines in a cohort of patients after liver transplantation (LT). MethodsLevels of T cell-mediated cytokines (e.g. Interferon-γ (IFN-γ)) and brain-derived cytokines (e.g. brain derived neurotrophic factor (BDNF), platelet derived growth factor (PDGF)) were measured by multiplex assays in plasma of 82 patients about 10 years after LT (17 with CNI free, 35 with CNI low dose, 30 with standard dose CNI immunosuppression) and 33 healthy controls. Data were related to psychometric test results and parameters of cerebral magnetic resonance imaging. ResultsIFN-γ levels were significantly higher in the CNI free LT patient group (p=0.027) compared to healthy controls. BDNF levels were significantly lower in LT patients treated with CNI (CNI low: p<0.001; CNI standard: p=0.016) compared to controls. PDGF levels were significantly lower in the CNI low dose group (p=0.004) and for PDGF-AB/BB also in the CNI standard dose group (p=0.029) compared to controls. BDNF and PDGF negatively correlated with cognitive function and brain volume (p<0.05) in the CNI low dose group. ConclusionOur results imply that long-term treatment with CNI suppresses BDNF and PDGF expression, both crucial for neuronal signaling, cell survival and synaptic plasticity and thereby may lead to cognitive dysfunction and neurodegeneration.

Infrequent tacrolimus-induced nephrotoxicity in French patients with steroid-dependent nephrotic syndrome.

Chronic nephrotoxicity with potentially irreversible lesions is a major concern regarding calcineurin inhibitor (CNI) treatment in children with severe forms of idiopathic nephrotic syndrome (INS). We retrospectively included all children on CNI for steroid-dependent INS with a duration of CNI treatment of more than 1year. Only patients in whom CNI could not be replaced by mycophenolate mofetil were included. All included patients underwent a kidney biopsy. All results were expressed as median and range. Twenty-one children (6 girls) were included. Age at disease onset was 49 (29-66) months and treatment duration on CNI was 30 (20-45) months. Age at kidney biopsy was 108 (78-170) months. Number of relapses was 7 (3-9) since disease onset. Serum creatinine level was transiently and moderately increased in two patients. Kidney biopsy revealed minimal change disease in 20/21 patients and focal segmental glomerulosclerosis in 1/21. Evidence for chronic CNI nephrotoxicity was found in one patient revealed by arteriolar hyalinosis and fibrosis in 50% of glomeruli. CNI-induced chronic nephrotoxicity was infrequent. In patients who require long-term and/or high-dose CNI treatment, kidney biopsies might be useful to exclude chronic CNI-induced lesions.

Persistent CD-19 depletion by rituximab is cost-effective in maintaining remission in calcineurin-inhibitor dependent podocytopathy.

A significant proportion of patients with minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are either steroid dependent or steroid resistant, requiring long-term calcineurin inhibitors (CNI) use. Rituximab has more favourable safety profile. The present study was undertaken to evaluate the efficacy and safety of rituximab in CNI-dependent patients. This was a prospective observational study conducted from July 2014 to February 2018. Steroid-dependent nephrotic syndrome or steroid-resistant nephrotic syndrome (biopsy proven MCD/FSGS), who were CNI dependent were enrolled. Mean age at enrolment was 22.77 ± 7.45 years. All patients received rituximab at a dose of 375 mg/m2 at entry in the study. CD-19 levels were monitored monthly and patients having CD-19 levels >5/μL and/or > 1% received additional low-dose (100 mg) of rituximab. A total of 24 patients were followed up for 12 months. At the end of 6 and 12 months, 87.5% and 79.16% of the patients achieved remission, respectively. Eight (33.33%) patients developed relapse. The mean dose of rituximab in the first year was 791 mg. The average cost of rituximab in the first year was 487.17$. Rituximab was well-tolerated, with mild infusion reactions, respiratory tract infection and oral candidiasis in 5 (20.83%), 5 (20.83%) and 1 (4.17%) patient, respectively. CD-19 targeted rituximab is a safe and cost-effective agent in remission maintenance in adults with CNI dependent. Over three-fourths of the patients with CNI-dependent podocytopathy maintain clinical remission with CD-19 targeted rituximab therapy.

Brain metabolic alterations in patients with long-term calcineurin inhibitor therapy after liver transplantation.

Calcineurin inhibitor (CNI) neurotoxicity after liver transplantation might be due to impairment of the cerebral metabolism. To investigate CNI-related alterations of brain metabolite distributions and associations between cognitive function and brain metabolism in patients with long-term CNI treatment after liver transplantation. Eighty-two patients (19 CNI free, 34 CNI low-dose and 29 standard-dose CNI immunosuppression) 10years after liver transplantation and 32 adjusted healthy controls underwent nonlocalised brain phosphorus magnetic resonance spectroscopy (MRS) and single voxel proton MRS in the parietal white matter to estimate brain metabolite contents. The MRS results were correlated with psychometric data assessing cognitive function. Phosphorus metabolite concentrations with the exception of phosphocreatine (PCr) were reduced in patients compared to controls. Particularly, patients with low-dose CNI therapy showed a significant decrease in adenosine triphosphate (0.209±0.012 vs 0.222±0.010; P<0.001) and a significant increase in PCr (0.344±0.026 vs 0.321±0.017; P<0.001) compared to controls. Myo-Inositol in the CNI free group (2.719±0.549 institutional unit [iu]) was significantly lower compared to controls (3.181±0.425 iu; P=0.02), patients on low-dose (3.130±0.513 iu; P<0.05) and standard-dose CNI therapy (3.207±0.632 iu; P<0.02). Glutamate and glutamine levels correlated negatively with cognitive function (Repeatable Battery for the Assessment of Neuropsychological Status Total Scale: R=-0.362, P=0.029). Long-term CNI therapy after liver transplantation might be associated with alterations of brain metabolites.

CD44-Positive Glomerular Parietal Epithelial Cells in a Mouse Model of Calcineurin Inhibitors-Induced Nephrotoxicity

Background/Aims: Calcineurin inhibitors (CNIs) such as cyclosporine A (CsA) and tacrolimus are immunosuppressants that are frequently used as “key drugs” in the fields of transplantation, steroid resistance, refractory nephrotic syndrome, and autoimmune disease. However, long-term CNI use causes nephrotoxicity, the features of which are arteriolar hyalinosis, tubular atrophy, striped interstitial fibrosis, and focal segmental glomerulosclerosis (FSGS). We investigated whether FSGS in CNI-induced nephrotoxicity is associated with CD44-positive glomerular parietal epithelial cells (PECs), which play a significant role in experimental and human FSGS pathogenesis. Methods: We utilized the mouse model of CsA-induced nephrotoxicity, as well as controls. Histopathological and functional data were sequentially collected from 1 to 25 weeks after CsA injection. Glomerular expression of CD44 was immunohistochemically evaluated, as were markers for glomerular podocytes and PECs. Results: Glomerular CD44 expression occurred from 2 weeks after CsA injection and gradually increased in the CsA group. CD44-positive glomerular cells showed coexpression of claudin-1 (PEC marker) but not of synaptopodin (podocyte marker). From 20 weeks after CsA injection, the cells formed a bridge between Bowman’s capsule and the capillary tuft. These features are compatible with those of activated PECs, in which increased foot process effacement leads to bridge formation, and subsequently to an increase in glomerulosclerosis and a decrease in the expression of podocyte markers from 20 weeks. Conclusion: CD44-positive (activated) PECs reflect extremely early podocyte injury in the progression of FSGS formation and may be a good marker for early detection of CNI-induced nephrotoxicity.

Mini-review of kidney disease following hematopoietic stem cell transplant .

Advancements in hematopoietic cell transplantation (HCT) have broadened indications for its use and resulted in more long-term survivors. Stem cell transplantation is associated with several well-known toxicities, although renal complications are not well defined. Acute and chronic kidney disease remains a common complication following transplantation itself. Incidence and risk factors for the development of chronic kidney disease (CKD) is less well understood. Recent estimates suggest that nearly 15% of subjects undergoing HCT will develop CKD, a complication that can progress to end-stage renal disease (ESRD), disrupts overall quality of life, and reduces overall survival. Several commonly-reported risk factors include acute kidney injury, graft-versus-host disease, and long-term calcineurin inhibitor use. This review highlights the incidence, timeline, etiology, risk factors, and prognosis of kidney disease in the setting of hematopoietic stem cell transplantation. Investigation of the causes of CKD is needed, as are ways to prevent, mitigate, and treat kidney injury. Renal disease importantly reflects prognosis, with dialysis-requiring patients carrying greater than 80% mortality after 3 years. Although CKD following HCT is common, prospective studies are needed to confirm risk factors and better define the underlying mechanisms in order to promote therapies that prevent this complication.

Calcineurin inhibitors and nephrotoxicity in children.

Calcineurin inhibitors (CNIs) are commonly given to transplant recipients of kidneys and other solid organs and to patients with immune disorders, such as steroid-resistant nephrotic syndrome, steroid-dependent nephrotic syndrome, and frequent relapse nephrotic syndrome. Although CNIs remain the most effective available immunosuppressant agent, there is clinical concern regarding possible long-term nephrotoxicity. This concern is especially significant in children who have a longer life expectancy and greater growth rate. In this review, we analyzed the literatures to identify original articles that examined use of CNIs in children who received organ transplantation and nephropathy to assess the available evidence of their nephrotoxicity. PubMed, Elsevier, and Tompson ISI Web of Knowledge were searched for identifying relevant papers. Clinical research supports the presence of CNI-related nephrotoxicity. However, some researchers have questioned the prevalence and seriousness of chronic CNIs nephrotoxicity, especially because the pathological lesions typically associated with long-term CNI use are nonspecific. Many researchers have focused on early markers of CNI nephrotoxicity, and the methods that may help prevent and manage nephrotoxicity. Future research should focus on investigating early markers of CNI nephrotoxicity and strategies for improved immunosuppressant therapy, and developing alternative treatments. CNI-mediated nephrotoxicity should always be taken seriously in clinic.

Neurotoxic Side Effects of Calcineurin Inhibitors in Patients After Liver Transplantation: Preliminary Results of a Quantitative MRI Study of the Brain

Background: Calcineurin inhibitors (CNI) are the most often used immunosuppressive drugs for the prevention of graft rejection after liver transplantation (LT). Long-term CNI treatment, however, is associated with cardiovascular disease and renal dysfunction. Considering the high frequency of neurotoxic side effects during the first weeks after treatment onset, long-term effects upon brain tissue structure and brain function must be expected. Aiming to estimate the long-term influence of CNI on cerebral microstructure and function after LT we carried out this quantitative MR study. Methods: Ninety patients (mean age: 58 ± 8) with a history of at least 3 years after liver transplantation were studied. They were divided into three groups according to their medication of the last two years: 23 patients without CNI, 36 patients with reduced dose of CNI (stable tacrolimus blood trough levels below 5 μg/l or stable cyclosporine A blood trough levels below 50 μg/l) and 31 patients with standard dose of CNI. Four patients were excluded due to incomplete examinations or artefacts. Thirty-two healthy gender- and age-adjusted volunteers served as reference group. All subjects underwent neuropsychological testing with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and MR examinations at 3 T (Verio, Siemens, Erlangen). The MR protocol included a T1 weighted GRE with 2 flip angles, a T2 weighted TSE with three echoes, a T2* weighted GRE with triple TE. Quantitative T1, relative proton density (PD, in ratio to water phantom), T2 and T2* maps were obtained on-the-fly on the MR system with an extended image reconstruction provided by the manufacturer, using monoexponential fitting to the signal intensity decay curves of the T1 GRE, T2 TSE and T2 GRE sequences, respectively, for region of interest (ROI) measurements, which were made in 18 ROIs located in cerebellum, brainstem, and cerebral gray and white matter. One-way ANOVA with Bonferroni corrected post hoc tests (α = 0.05) were used to compare the qMRI data and Kruskal–Wallis test to compare the RBANS scores between groups. Results: RBANS scores revealed that patients receiving CNI owned a significantly worse visuospatial/constructional ability, and patients with low dose CNI an overall impaired cognitive function compared to controls. qMRI revealed significant microstructural changes, especially in frontal white matter, with higher PD and T2 (CNI free) and higher T2* (CNI free and low dose), indicating increased free water (PD and T2) and reduced metabolism (T2*) within brain tissue of these patients compared to controls. Interestingly, little change has been found in patients with standard CNI dose, indicating probably different phenotypes between patients, by considering that the CNI dose was applied depending on patients’ tolerability to CNI medication. Conclusion: These preliminary results showed that long term medication with CNI affects tissue microstructure in human brain and the brain function after liver transplantation (Figure 1). The authors have none to declare.

What is a reflex? A guide for understanding disorders of consciousness.

Uncertainty in diagnosing disorders of consciousness, and specifically in determining whether consciousness has been lost or retained, poses challenging scientific and ethical questions. Recent neuroimaging-based tests for consciousness have cast doubt on the reliability of behavioral criteria in assessing states of consciousness and generate new questions about the assumptions used in formulating coherent diagnostic criteria. The reflex, a foundational diagnostic tool, offers unique insight into these disorders; behaviors produced by unconscious patients are thought to be purely reflexive, whereas those produced by conscious patients can be volitional. Further investigation, however, reveals that reflexes cannot be reliably distinguished from conscious behaviors on the basis of any generalizable empirical characteristics. Ambiguity between reflexive and conscious behaviors undermines the capacity of the reflex to distinguish between disorders of consciousness and has implications for how these disorders should be conceptualized in future diagnostic criteria.

The role of everolimus in liver transplantation.

During the last 5 decades, liver transplantation has witnessed rapid development in terms of both technical and pharmacologic advances. Since their discovery, calcineurin inhibitors (CNIs) have remained the standard of care for immunosuppression therapy in liver transplantation, improving both patient and graft survival. However, adverse events, particularly posttransplant nephrotoxicity, associated with long-term CNI use have necessitated the development of alternate treatment approaches. These include combination therapy with a CNI and the inosine monophosphate dehydrogenase inhibitor mycophenolic acid and use of mammalian target of rapamycin (mTOR) inhibitors. Everolimus, a 40-O-(2-hydroxyethyl) derivative of mTOR inhibitor sirolimus, has a distinct pharmacokinetic profile. Several studies have assessed the role of everolimus in liver transplant recipients in combination with CNI reduction or as a CNI withdrawal strategy. The efficacy of everolimus-based immunosuppressive therapy has been demonstrated in both de novo and maintenance liver transplant recipients. A pivotal study in 719 de novo liver transplant recipients formed the basis of the recent approval of everolimus in combination with steroids and reduced-dose tacrolimus in liver transplantation. In this study, everolimus introduced at 30 days posttransplantation in combination with reduced-dose tacrolimus (exposure reduced by 39%) showed comparable efficacy (composite efficacy failure rate of treated biopsy-proven acute rejection, graft loss, or death) and achieved superior renal function as early as month 1 and maintained it over 2 years versus standard exposure tacrolimus. This review provides an overview of the efficacy and safety of everolimus-based regimens in liver transplantation in the de novo and maintenance settings, as well as in special populations such as patients with hepatocellular carcinoma recurrence, hepatitis C virus-positive patients, and pediatric transplant recipients. We also provide an overview of ongoing studies and discuss potential expansion of the role for everolimus in these settings.

A Randomized, Open-Label Study of Sirolimus Versus Cyclosporine in Primary De Novo Renal Allograft Recipients

Despite a decreased incidence of acute rejection and early renal allograft loss due to calcineurin inhibitors (CNIs) in transplant recipients, nephrotoxicity associated with long-term CNI use remains an important issue. This study evaluated whether a CNI-free regimen, including sirolimus, mycophenolate mofetil, corticosteroids, and anti-interleukin-2 receptor antibody induction, results in improved long-term renal function. This open-label, randomized, parallel group, comparative study in primary de novo renal transplant recipients was planned for 48 months but terminated early because of high acute rejection rates in the sirolimus arm. Enrollment was stopped after ≈12 months, with 475 transplanted patients randomized (2:1) to sirolimus (n=314) or cyclosporine A (CsA) treatment (n=161). Mean length of follow-up after transplantation was 190 days; this article focuses on available data through 6 months. Mean±SD on-therapy Nankivell-calculated glomerular filtration rate was not significantly different between the sirolimus (69.1±18.7 mL/min) and CsA (66.0±15.2 mL/min) treatment groups. Occurrence and length of delayed graft function was not significantly different between groups. Patients in the sirolimus group experienced numerically lower survival rates (96.9% vs. 99.4%; P=0.14), with nine deaths reported with sirolimus and one with CsA; higher rates of biopsy-confirmed acute rejection (21.4% vs. 6.1%; P<0.001); and higher rates of discontinuations due to adverse events (17.4% vs. 6.8%; P=0.001). A sirolimus-based, CNI-free immunosuppressive regimen, when used with mycophenolate mofetil, corticosteroids, and anti-interleukin-2 receptor antibody induction, was associated with high rates of biopsy-confirmed acute rejection compared with CsA-based immunosuppression and is not recommended.

Differing Effects of Rapamycin or Calcineurin Inhibitor on T-Regulatory Cells in Pediatric Liver and Kidney Transplant Recipients

In a cross-sectional study, we assessed effects of calcineurin inhibitor (CNI) or rapamycin on T-regulatory (Treg) cells from children with stable liver (n = 53) or kidney (n = 9) allografts several years posttransplant. We analyzed Treg number, phenotype, suppressive function, and methylation at the Treg-specific demethylation region (TSDR) using Tregs and peripheral blood mononuclear cells. Forty-eight patients received CNI (39 as monotherapy) and 12 patients received rapamycin (9 as monotherapy). Treg numbers diminished over time on either regimen, but reached significance only with CNI (r =-0.424, p = 0.017). CNI levels inversely correlated with Treg number (r =-0.371, p = 0.026), and positively correlated with CD127+ expression by Tregs (r = 0.437, p = 0.023). Patients with CNI levels >3.6 ng/mL had weaker Treg function than those with levels <3.6 ng/mL, whereas rapamycin therapy positively correlated with Treg numbers (r = 0.628, p = 0.029) and their expression of CTLA4 (r = 0.726, p = 0.041). Overall, CTLA4 expression, TSDR demethylation and an absence of CD127 were important for Treg suppressive function. We conclude that rapamycin has beneficial effects on Treg biology, whereas long-term and high dose CNI use may impair Treg number, function and phenotype, potentially acting as a barrier to attaining host hyporesponsiveness to an allograft.

Incidence of and risk factors for symptomatic benign prostatic hyperplasia in kidney transplant recipients: A cohort study

Objective. The purpose of this study was to investigate the effect of immunosuppressants on the incidence of and risk factors for symptomatic benign prostatic hyperplasia (BPH) in relative-donor kidney transplant recipients. Material and methods. A retrospective cohort study was performed to determine the incidence of symptomatic BPH in kidney transplant recipients according to standard diagnostic criteria, the expression levels of keratinocyte growth factor, transforming growth factor-β (TGF-β) and serum testosterone, and the CD4/CD8 ratio in T lymphocytes. Results. The incidence of symptomatic BPH (50–59-year-old group, p = 0.010; 60–69-year-old group, p = 0.004; ≥ 70-year-old group, p = 0.032), testosterone level (50–59-year-old group, p = 0.045; 60–69-year-old group, p = 0.035; ≥ 70-year-old group, p = 0.041) and the CD4/CD8 ratio (50–59-year-old group, p = 0.013; 60–69-year-old group, p = 0.010; ≥ 70-year-old group, p = 0.015) of kidney transplant recipients with long-term calcineurin inhibitor (CNI) and prednisone use were all lower than those values in a normal group that had not received transplants. The TGF-β (p < 0.001) expression level was higher in kidney transplant recipients than in the non-transplant group, and the keratinocyte growth factor expression level was not statistically different between the kidney transplant recipients and the non-transplant group. Conclusions. Kidney transplant recipients with long-term CNI and prednisone use may have a low incidence of symptomatic BPH, which may be related to TGF-β and keratinocyte growth factor expression, testosterone levels and lymphocyte infiltration. Further high-quality prospective studies are needed to confirm these conclusions.

Specificity of Histological Markers of Long-Term CNI Nephrotoxicity in Kidney-Transplant Recipients Under Low-Dose Cyclosporine Therapy

The specificity of chronic histological lesions induced by calcineurin inhibitors (CNI) is often questioned, but few studies have directly compared long-term lesions in renal-transplant patients who received this treatment and those who did not. We therefore conducted a retrospective study of 141 kidney-transplant recipients treated with (n = 48) or without (n = 93) cyclosporine (CsA) to compare the histological lesions observed at 3-month, 24-month and 10-year protocol biopsies. All of the chronic elementary lesions (glomerulosclerosis, interstitial fibrosis, tubular atrophy, arteriolar hyalinosis, fibrointimal thickening) progressed in frequency and severity in both groups, although significantly more in the CsA group. Ten-year biopsy results showed that 92% of patients in the CsA-treated group and 65% in the control group had arteriolar hyalinosis lesions. When we focused on muscular arteriolar hyaline deposits more specific to CsA arteriolopathy, we observed these lesions in 68% of CsA patients and 28% of patients who had never received CsA. CsA was not the sole factor involved in the development of arteriolar hyalinosis and was independently associated with an increased risk of graft loss. In summary, we observed that histological lesions commonly attributed to CsA nephrotoxicity were not sufficiently specific to definitively diagnose CNI nephrotoxicity.