Calcineurin Inhibitors Cyclosporine Research Articles

Mycophenolate mofetil for sustained remission in nephrotic syndrome.

The clinical application of mycophenolate mofetil (MMF) has significantly widened beyond the prophylaxis of acute and chronic rejections in solid organ transplantation. MMF has been recognized as an excellent treatment option in many immunologic glomerulopathies. For children with frequently relapsing nephrotic syndrome (FRNS) or steroid-dependent nephrotic syndrome (SDNS) experiencing steroid toxicity, MMF has been recommended as a steroid-sparing drug. Uncontrolled studies in patients with FRNS and SDSN have shown that many patients can achieve sustained remission of proteinuria with MMF monotherapy. Three randomized controlled trials have similarly demonstrated that MMF is beneficial in these patients, but less effective than the calcineurin inhibitors cyclosporin A or tacrolimus. Some, but not all, patients with steroid-resistant nephrotic syndrome (SRNS) may also respond to MMF, usually given in combination with other drugs, with partial or complete remission. There are important limitations to the interpretation and comparability of these studies including study design, sample size, patient selection, clinical endpoints, carry-over effects, and duration of follow-up. In all studies, MMF had relatively few side effects, no nephrotoxicity, or no systemic toxicity. MMF is teratogenic, and contraceptive advice is required in females. There is a poor correlation between MMF dose and mycophenolic acid (MPA) exposure and significant inter- and intra-patient variability in drug pharmacokinetics. A higher estimated MPA-AUC0-12 target range than recommended for pediatric renal transplant recipients is essential to prevent relapses. Therefore, therapy should be guided by drug monitoring to avoid relapses. Further studies are needed to test the efficacy of MMF in inducing remission and, as part of a combination therapy, achieving sustained remission in patients with SRNS.

Safety and Efficacy of Combination Treatment With Calcineurin Inhibitors and Vedolizumab in Patients With Refractory Inflammatory Bowel Disease

Little is known about the efficacy and safety of induction therapy with calcineurin inhibitors in combination with vedolizumab for patients with Crohn's disease (CD) or ulcerative colitis (UC). We analyzed the outcomes of patients receiving vedolizumab along with calcineurin inhibitors. We collected data on patients with CD (n= 9) or UC (n= 11) who began treatment with vedolizumab from May 20, 2014, through March 30, 2015, and received calcineurin inhibitors (tacrolimus or cyclosporin) during the first 12 months of vedolizumab therapy. Clinical activity scores and inflammatory markers were measured at baseline and at weeks 14, 30, and 52 of vedolizumab treatment. Clinical remission was defined as a Harvey-Bradshaw index score ≤4 or short clinical colitis activity index score ≤2; steroid-free clinical remission was defined as clinical remission without corticosteroids. By week 14 of treatment, 44% of the patients with CD and 55% of the patients with UC achieved steroid-free clinical remission; after 52 weeks of treatment, 33% of the patients with CD and 45% of the patients with UC were in steroid-free clinical remission. Seven patients received salvage therapy with a calcineurin inhibitor after primary nonresponse to vedolizumab-1 of the 2 patients with UC and 2 of 5 patients with CD stopped taking the calcineurin inhibitors and achieved steroid-free remission at week 52. In total, 16 patients (59%) received 52 weeks of treatment with vedolizumab. Three serious adverse events were associated with calcineurin inhibitors. Combination therapy of vedolizumab with either cyclosporin or tacrolimus is effective and safe at inducing and maintaining clinical remission in patients with CD and UC with up to 52 weeks of follow-up evaluation. Larger studies of the ability of calcineurin inhibitors to induce remission in patients on vedolizumab are warranted.

Abstract 512: Bcl11b is a Newly Identified Regulator of Vascular Smooth Muscle Function and Stiffness

Background: B-cell leukemia 11b (Bcl11b) is a zinc-finger transcription factor known as master regulator of T lymphocytes and neuronal development during embryogenesis. However, a role for Bcl11b in the cardiovascular system has never been described. Based on human findings from a genome-wide association study (GWAS) that a gene desert region downstream of BCL11B , known to function as BCL11B enhancer, harbors single nucleotide polymorphisms (SNPs) associated with increased arterial stiffness, we sought to examine relations between Bcl11b and arterial function. Methods and Results: We found for the first time that Bcl11b is expressed in the vascular smooth muscle (VSM) of human and murine vasculature and transcriptionally regulates the expression of VSM contractile proteins smooth muscle myosin and smooth muscle α-actin. Lack of Bcl11b in VSM-specific Bcl11b null mice (BSMKO) resulted in an increased expression of Ca ++ -calmodulin-dependent serine/threonine phosphatase calcineurin in BSMKO VSM cells and aortas, which were inversely correlated with levels of phosphorylated VASP S239 , a calcineurin de-phosphorylation target. Decreased pVASP S239 in BSMKO aortas was associated with increased actin polymerization (F/G actin ratio), consistent with pVASP S239 ’s function as regulator of cytoskeletal actin rearrangements, and was normalized by treatment with calcineurin inhibitor cyclosporine A. Functionally, Bcl11b deletion in VSM cells translated in increased aortic force, stress and wall tension, measured ex vivo in BSMKO aortas in organ baths, and increased pulse wave velocity, the in vivo index of arterial stiffness, in BSMKO mice compared to WT littermates. Moreover, Bcl11b and pVASP S239 expression were decreased in aortas of obese and aged mice, two models of arterial stiffness. Bcl11b deletion in VSM had no effect on baseline blood pressure or angiotensin II-induced hypertension, measured in conscious WT and BSMKO mice by radiotelemetry, but dramatically increased the incidence of angII-induced aortic aneurysms in BSMKO mice. Conclusions: Taken together, our results identify VSM Bcl11b as a novel and crucial regulator of VSM cell phenotype and vascular structural and functional integrity

Rituximab Use in Nephrotic Syndrome

Background: Nephrotic syndrome may be caused by primary (idiopathic) renal disease or by a variety of secondary causes. Patients present with marked edema, proteinuria, hypoalbuminemia, and often hyperlipidemia. Treatment of most patients should include fluid and sodium restriction, oral or intravenous diuretics, and angiotensin-converting enzyme inhibitors. Adults with nephrotic syndrome may benefit from corticosteroid treatment. The treatment of patients with the steroid-resistant nephrotic syndrome (SRNS) and steroid-dependent nephrotic syndrome (SDNS) is challenging. On the basis of suggestions that B lymphocytes are crucial in the pathogenesis of the nephrotic syndrome, rituximab (a monoclonal antibody against CD20 antigen) is used in treatment of these patients. Aim of study: To evaluate the role of rituximaband mycophenolic acid in treatment of patientswith steroid-resistant (SRNS) and steroid-dependent nephrotic syndrome (SDNS), whom not respond or relapse after calcineurin inhibitor (CNI) (tacrolimus or cyclosporine) had been used. Patients and methods: Case series study was done between 2012 - 2015 in AL-Sadder Teaching Hospital Nephrology Center and record 40 patients with different age groups, males and females with different histopathological types (Minimal Change Glomerulonephritis, Focal Segmental Glomerulosclerosis, Mesengeo Prolifrative Glomerulonephritis). These patients were taking prednisilone and\or calcineurin inhibitor (tacrolimus “prograf”) or (cyclosporine “sandimmune”), and they get either Steroid Dependent Nephrotic Syndrome or Steroid Resistant Nephrotic Syndrome with frequent admission more than four time per year. To these patients we start rituximab intravenous infusion monthly for at least six months with the use of steroid and mycophenolate mofetil during these six months. The patients followed up for 3-12 months after initiation of rituximab by different investigations and the patients were classified according to their response into complete, partial and no response. After one year stop rituximab treatment, follow the patients clinically and by investigations for (1-2) years to determine which patients get relapse. Results: Majority (80%) of patients with nephrotic syndrome who had good response to rituximab were younger age group < 15 years. Better response to rituximab associated with Minimal Change Glomerulonephritis. There was significant reduction in blood urea, serum creatinine, urine (protein/creatinine) ratio and serum cholesterol. Serum albumin was significant elevated. Response to rituximab was not significantly associated with gender or steroid response. Majority of patients with good response not relapse and need more time for follow up. Relapsing after stopping rituximab not significantly associated with age, gender, histopathological type and steroid response. Conclusion: Rituximab and mycophenolate mofetil used in steroid-resistant nephrotic syndrome to get ride from side effects of calcineurine inhibitor (tacrolimus or cyclosporine). Rituximab and mycophenolate mofetil used in steroid-dependent nephrotic syndrome after calcineurine inhibitorto get ride from side effects of steroid. Improvement in renal function is result from stopping of calcineurine inhibitor (nephrotoxic drugs) and/or from rituximab and mycophenolate mofetil. Cost of rituximab is less than the cost that needed if the patients had frequent admissions to the hospital or developed renal failure and ended with dialysis.

Circulating plasma microRNA profiling in patients with polymyositis/dermatomyositis before and after treatment: miRNA may be associated with polymyositis/dermatomyositis

BackgroundMicroRNAs (miRNAs) are involved in the regulation of key biological processes and have been implicated in various diseases, including autoimmune disorders. The pathogenesis of polymyositis (PM) and dermatomyositis (DM) is considered to be mediated by autoimmune reactions. To determine miRNA role in the development and progression of PM and DM, we performed plasma miRNA profiling in PM/DM patients before and after treatment.MethodsTotal RNA was isolated from plasma of 10 patients before and after treatment with prednisolone, or, in case of prednisolone resistance or complications, with the combination of calcineurin inhibitors (cyclosporine or tacrolims) and/or pulse intravenous cyclophosphamide. The expression of miRNAs was determined using miRNA microarray and validated by qRT-PCR.ResultsMore differentially expressed miRNAs were found in plasma of DM patients compared to PM patients before and after treatment, and their profiles were different. Among the differentially expressed plasma miRNA identified by microarray, the levels of hsa-miR-4442 were confirmed by qRT-PCR to be significantly decreased by treatment. In addition, plasma hsa-miR-4442 content in active PM/DM significantly exceeded that in other active autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus, as well as in healthy individuals. The level of plasma hsa-miR-4442 was positively correlated with Skeletal Disease Activity in MITAX (Myositis Intention to Treat Activity Index).ConclusionThis is the first report describing plasma miRNA expression profiles in PM/DM patients. The present data suggest that plasma levels of miRNAs may be associated with polymyositis/dermatomyositis and hsa-miR-4442 could be used as a biomarker for PM/DM diagnosis and/or disease activity.

Effect of cyclosporine, tacrolimus and sirolimus on cellular senescence in renal epithelial cells

IntroductionIn transplantation medicine calcineurin inhibitors (CNI) still represent the backbone of immunosuppressive therapy. The nephrotoxic potential of the CNI Cyclosporine A (CsA) and Tacrolimus (FK506) is well recognized and CNI not only have been linked with toxicity, but also with cellular senescence which hinders parenchymal tissue regeneration and thus may prime kidneys for subsequent insults. To minimize pathological effects on kidney grafts, alternative immunosuppressive agents like mTOR inhibitors or the T-cell co-stimulation blocker Belatacept have been introduced. MethodsWe compared the effects of CsA, FK506 and Sirolimus on the process of cellular senescence in different human renal tubule cell types (HK2, RPTEC). Telomere length (by real time PCR), DNA synthesis (by BrdU incorporation), cell viability (by Resazurin conversion), gene expression (by RT-PCR), protein (by western blotting), Immuncytochemistry and H2O2 production (by Amplex Red® conversion) were evaluated. ResultsDNA synthesis was significantly reduced when cells were treated with cyclosporine but not with tacrolimus and sirolimus. Resazurin conversion was not altered by all three immunosuppressive agents. The gene expression as well as protein production of the cell cycle inhibitor p21 (CDKN1A) but not p16 (CDKN2A) was significantly induced by cyclosporine compared to the other two immunosuppressive agents when determined by western blotting an immuncytochemistry. Relative telomere length was reduced and hydrogen peroxide production increased after treatment with CsA but not with FK506 or sirolimus. ConclusionIn summary, renal tubule cells exposed to CsA show clear signs of cellular senescence where on the contrary the second calcineurin inhibitor FK506 and the mTOR inhibitor sirolimus are not involved in such mechanisms. Chronic renal allograft dysfunction could be in part triggered by cellular senescence induced by immunosuppressive medication and the choice of drug could therefore influence long term outcome. Tacrolimus and Sirolimus are equally effective in avoiding cellular senescence compared to cyclosporine at least in parts due to a lack of induction of reactive oxygen species.

Impact of Immunosuppressive Drugs on the Metabolism of TCells.

Energetic metabolism supports rapid cell growth and proliferation, differentiation, polarization, and effector functions of T cells. T lymphocytes have the remarkable plasticity that allows them to shape their metabolism to adapt to extracellular and intracellular cues, a process that involves molecular modules referred to as "metabolic checkpoints" that sense metabolic signals and transduce effector messages. These metabolic checkpoints may represent a novel therapeutic strategy for immune modulation. Chemical immunosuppressive drugs including mammalian target of rapamycin inhibitors (sirolimus and everolimus), calcineurin inhibitors (tacrolimus and cyclosporine), and purine and pyrimidine synthesis inhibitors (6-mercaptopurine, mycophenolic acid, and methotrexate) are widely prescribed for the treatment ofautoimmune and inflammatory diseases and for controlling alloimmunity in interfering with the signals that activate and allow T cells to proliferate. Emerging evidence indicates that these drugs also target T-cell metabolism and metabolic checkpoints, which, as a consequence, could contribute to their immunosuppressive effects. These examples raise the issue of how the modulation of these metabolic checkpoints can regulate T-cell activation, differentiation, and function. In this review we highlight emerging concepts about the modulation of metabolic reprogramming in T-cell responses by immunosuppressive drugs and how potential therapeutic interventions influence T-cell fate and effector function.

PD54 Associated Factors Renal Graft Loss Using Real-World Evidence In Brazil

Introduction:Renal transplantation is considered a cost-effective treatment compared to dialysis and represents a significant percentage of public health resources. Post-transplant treatment requires the use of three immunosuppressive drugs. The immunosuppressive regimens consists of a corticosteroid, a calcineurin inhibitor (cyclosporine or tacrolimus) and an antiproliferative agent (azathioprine or mycophenolate) and also by sirolimus or everolimus. In Brazil, the Unified Health System (as known as Sistema Único de Saúde - SUS) is responsible for 95 percent of all kidney transplants performed, as well as ensuring access to immunosuppressive drugs. Therefore, there is a huge and growing economic impact caused by the distribution of these drugs in SUS. We evaluated the factors associated with kidney graft loss in patients who received deceased donor organ and used maintenance immunosuppressive regimens in SUS, in fifteen years.Methods:We analyzed a nationwide cohort of kidney transplant recipients from January 2000 to December 2015 developed through deterministic-probabilistic linkage of SUS administrative databases: Hospital Information System (SIH/SUS); Subsystem for High Complexity Procedures (SIA/SUS) and the Mortality Information System (SIM). Graft loss was defined as death or dialysis for more than three months. All regimens included corticosteroid. We used Cox proportional hazards model to evaluate the factors associated with progression to graft loss.Results:In total, 18,333 patients were included; 58.5 percent used tracolimus+mycophenolate, 11.7 percent cyclosporine+mycophenolate, 8.9 percent tacrolimus+azathyoprine, 5.5 percent cyclosporine+azathyoprine and 15.4 percent received other immunosuppressive regimens (sirolimus+mycophenolate, everolimus+mycophenolate, tacrolimus, mycophenolate, cyclosporine, azathyoprine) . Most patients were male with a median age of 46 years. A higher risk of graft loss was associated with the use of tracolimus+mycophenolate (HR = 1.069; 95% CI, 0.999–1.146), sirolimus+mycophenolate (HR1.395;95% CI, 1 .150–1.692), tracolimus (monotherapy) (1.468;1.239–1.739); mycophenolate (monotherapy) (1.297;1.126–1.493), male gender (1.144; 1.072–1.221), an additional year of age (1.010; 1.007–1.013), a median dialysis period greater than 38 months (1.266; 1.182–1.356), a diagnosis of diabetes (1.211; 1.071–1.367) and a diagnosis of arterial hypertension (1.209; 1.134–1.288) (HR=1.468;95% CI,1.239 −1.739); mycophenolate (monotherapy) (HR = 1.297; 95% CI, 1.126–1.493), male gender (HR = 1.144; 95% CI 1.072–1.221), an additional year of age (HR = 1.010; 95% CI, 1.007–1.013), a median dialysis period greater than 38 months (HR = 1.266; 95% CI, 1.182–1.356), a diagnosis of diabetes (HR = 1.211; 95% CI, 1.071–1.367) and a diagnosis of arterial hypertension (HR = 1.209; 95% CI, 1.134–1.288)as the primary cause of chronic kidney disease.Conclusions:In Brazil, the use of regimens mycophenolate, tacrolimus, tacrolimus+mycophenolate was associated a higher risk of graft loss, among other factors. The choice of drug therapy is one of the few factors that influence survival amenable to direct action by health professionals. Therefore, the results of this study are important and should be disseminated aiming to better outcomes for kidney transplant patients.

The influence of immunosuppressants on direct-acting antiviral therapy is dependent on the hepatitis C virus genotype.

Direct-acting antivirals (DAAs) have substantially increased sustained virological response rates after liver transplantation, with improved tolerance compared to interferon-based therapy. The influence of immunosuppressive agents on the efficacy of DAAs has not been clarified. Subgenomic hepatitis C virus (HCV) replicons for genotype (GT) 1b, 2b, 3a, and 4a were treated with the mammalian target of rapamycin (mTOR) inhibitors everolimus and sirolimus or with the calcineurin inhibitors (CNIs) cyclosporine or tacrolimus, either alone or in combination with selected DAAs. Cell proliferation-related effects were excluded with MTT assays. HCV replication activity was quantified by quantitative real-time polymerase chain reaction or luciferase assay. Addition of either mTOR inhibitor to the DAA daclatasvir (DAC) resulted in a 30% increase in antiviral activity compared to DAC alone for HCV GT2a, GT3a, and GT4a (all P≤.01). Similar results were obtained using sofosbuvir and ledipasvir. In contrast, addition of either mTOR inhibitor to DAC induced a 30% reduction in antiviral activity in GT1b cells (P≤.01 vs DAC alone). Neither CNI affects the antiviral activity of the DAAs in any HCV GT. For patients with HCV GT2a, GT3a, or GT4a infection, mTOR-based immunosuppressive therapy may be beneficial. CNI-based therapy may be more efficacious in GT1b patients, as mTOR inhibitors seem to impair antiviral efficacy of DAAs in HCV GT1b infection.

A Retrospective Chart Review to Assess Burden of Illness Among Patients with Severe Aplastic Anemia with Insufficient Response to Immunosuppressive Therapy

Background: Aplastic anemia (AA) is a rare disease, with an incidence of 1-2 new cases per million per year in Europe and North America. Primary therapies for AA for patients who do not have a sibling or matched unrelated donor or are unfit for allogeneic hematopoietic stem cell transplantation (HSCT) include immunosuppressive therapy (IST) with the combination of antithymocyte globulin (ATG) and calcineurin inhibitors. Therapeutic options beyond IST are limited and include eltrombopag, which was approved by the US FDA for use in patients with severe AA who fail to respond adequately to IST. The health economic burden of this rare and debilitating condition is poorly understood, especially for refractory cases.Objective: To examine health resource utilization associated with severe AA among patients with insufficient response to IST in real-world practice settings in a recent time period.Methods: We conducted a retrospective, longitudinal chart review of patients with severe AA treated at clinical centers in the US (Dana-Farber Cancer Institute [DFCI]) and France (Service d'Hématologie Greffe, Hôpital Saint-Louis [AGRAH]). Severe AA in this study was identified as having bone marrow cellularity <25%, or 25-50% with <30% residual hematopoietic cells; and at least two of the following laboratory findings: neutrophil count <500 cell/µL, platelets <20,000/µL, reticulocyte count <20,000/µL. Eligible patients were ≥18 years old, first diagnosed with severe AA between January 1, 2006 and January 31, 2016, had insufficient response to at least one course of IST following severe AA diagnosis, and had ≥12 months of medical data after first diagnosis with severe AA. Patients with congenital disorders of hematopoiesis were excluded. Kaplan-Meier method was used to analyze time from first IST to time of HSCT. Cumulative incidence and incidence rates were used to summarize frequency of blood transfusions and AA-related health care resource utilization. The study was approved by local IRB.Results: The study included 34 refractory severe AA patients (NDFCI=20; NAGRAH =14). Mean age at severe AA diagnosis was 43.3 (standard deviation [SD]: 16.8) years and 52.9% (18/34) of patients were women. Median follow-up time after severe AA diagnosis was 56.1 (range: 12.0-118.7) months. Thirty-three (97.1%) patients received ATG in combination with calcineurin inhibitor (cyclosporine or tacrolimus) with or without corticosteroid as primary therapy. Among patients treated with ATG, 51.5% (17/33) patients received only one course of ATG and 48.5% (16/33) patients received ≥2 courses of ATG. The most common secondary AA therapy included eltrombopag (17.6%, N=6) and androgens (8.8%, N=3). The median treatment duration for eltrombopag was 6.4 (range: 5.6-53.4) months. The average frequency of transfusions per patient per month was 2.8 (SD: 2.8) red blood cell (RBC) and 3.3 (SD: 3.5) platelet transfusions. The mean AA-related health care utilization rates per patient per year were 0.8 (95% confidence interval [CI]: 0.6, 1.0) for inpatient visits, 0.5 (95% CI: 0.4, 0.8) for emergency room visits, and 19.1 (95% CI: 17.9, 20.5) for office visits prior to undergoing HSCT. Among the subgroup of patients treated with eltrombopag, the mean number of RBC transfusions per patient per month was reduced from 2.4 (SD: 2.0) before to 0.9 (SD: 0.8) after eltrombopag treatment, and from 3.0 (SD: 2.3) to 1.3 (SD: 1.6) for platelet transfusions. Similarly, AA-related health care utilization rates were lower after eltrombopag initiation (∆inpatient visits: -0.3 (95% CI: -1.1, 0.5); ∆emergency room visits: -0.6 (95% CI: -1.5, 0.4); ∆office visits: -11.7 (95% CI: -16.2, -7.1) per patient per year). Thirty (88.2%) patients received HSCT with a median time of 12.9 (95% CI: 7.9, 17.3) months after first IST initiation. During the follow-up period, 29.4% (10/34) patients died; nine patients died after HSCT. Two (5.9%) patients transformed to myelodysplastic syndrome and/or acute myeloid leukemia.Conclusion: This is one of the first studies to quantify the transfusion and health resource burden of refractory severe AA. In a small subgroup of patients receiving eltrombopag, there was a trend toward reduction in blood transfusion frequency, AA-related hospitalization rate, and outpatient office and emergency room visits after eltrombopag initiation. DisclosuresPeffault De Latour:Pfizer: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Alexion Pharmaceuticals, Inc.: Consultancy, Honoraria, Research Funding; Amgen: Research Funding. Huynh:Novartis Pharmaceuticals Corporation: Research Funding. Ivanova:Novartis, GSK, Teva, Lilly: Research Funding. Totev:Novartis Pharmaceuticals Corporation, Shire Pharmaceuticals Inc.: Research Funding. Bilginsoy:Novartis Pharmaceuticals Corporation: Research Funding. Roy:Novartis: Employment, Equity Ownership. Duh:Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Research Funding; Novartis Pharmaceuticals Corporation: Research Funding.

Self-Destructive Behavior among Full-Donor Blood and Marrow Grafts and the Association with Long-Term Graft Function

Self-Destructive Behavior among Full-Donor Blood and Marrow Grafts and the Association with Long-Term Graft Function

Myeloid-Derived Suppressor Cells Ameliorate Cyclosporine A-Induced Hypertension in Mice.

The calcineurin inhibitor cyclosporine A (CsA) suppresses the immune system but promotes hypertension, vascular dysfunction, and renal damage. CsA decreases regulatory T cells and this contributes to the development of hypertension. However, CsA's effects on another important regulatory immune cell subset, myeloid-derived suppressor cells (MDSCs), is unknown. We hypothesized that augmenting MDSCs would ameliorate the CsA-induced hypertension and vascular and renal injury and dysfunction and that CsA reduces MDSCs in mice. Daily interleukin-33 treatment, which increased MDSC levels, completely prevented CsA-induced hypertension and vascular and renal toxicity. Adoptive transfer of MDSCs from control mice into CsA-treated mice after hypertension was established dose-dependently reduced blood pressure and vascular and glomerular injury. CsA treatment of aortas and kidneys isolated from control mice for 24 hours decreased relaxation responses and increased inflammation, respectively, and these effects were prevented by the presence of MDSCs. MDSCs also prevented the CsA-induced increase in fibronectin in microvascular and glomerular endothelial cells. Last, CsA dose-dependently reduced the number of MDSCs by inhibiting calcineurin and preventing cell proliferation, as other direct calcineurin signaling pathway inhibitors had the same dose-dependent effect. These data suggest that augmenting MDSCs can reduce the cardiovascular and renal toxicity and hypertension caused by CsA.

Traitements du syndrome néphrotique cortico-dépendant de l’enfant

Primary nephrotic syndrome (NS) is the most common glomerular disease in children. It is characterized by massive proteinuria and hypoalbuminemia. It typically has a sudden onset and more than 70% of patients will experience at least one relapse. An immunological origin has long been postulated, although the precise molecular mechanisms underlying the disease remain debated. Steroids are the first-line therapy with cumulative dose and duration of initial treatment varying among countries. Steroid-sparing agents may be indicated in case of steroid-dependency or frequent relapses. However, no consensus exists regarding the different treatment options. These treatments are mostly suspensive and therefore, need to be prolonged for several months. Levamisole, an antihelminthic drug, also has an immunomodulatory function, and alone or in combination with steroids, it can decrease cumulative steroid dose and relapses. It is usually well tolerated, and its principal side effects are cytopenia and elevated liver enzymes. Mycophenolate mofetil is an immunosuppressive agent whose reported side effects are cytopenia and diarrhea. Calcineurin inhibitors (cyclosporine or tacrolimus) have long been used in steroid-dependent patients. Their major side effects are hirsutism, gum hypertrophy, and nephrotoxicity, leading to interstitial kidney fibrosis and chronic kidney disease. Cyclophosphamide is an efficient treatment but its gonadal toxicity is a major drawback to its use. More recent drugs such as rituximab are very effective but require hospitalization for the infusion and induce an increased risk of opportunistic infection, prolonged neutropenia, and anaphylaxis. In this review, we present the available treatments, their indications, and the side effects.

Src-family kinases negatively regulate NFAT signaling in resting human T cells.

T cell signaling is required for activation of both natural and therapeutic T cells including chimeric antigen receptor (CAR) T cells. Identification of novel factors and pathways regulating T cell signaling may aid in development of effective T cell therapies. In resting human T cells, the majority of Src-family of tyrosine kinases (SFKs) are inactive due to phosphorylation of a conserved carboxy-terminal tyrosine residue. Recently, a pool of enzymatically active SFKs has been identified in resting T cells; however, the significance of these is incompletely understood. Here, we characterized the role of active SFKs in resting human T cells. Pharmacologic inhibition of active SFKs enhanced distal TCR signaling as measured by IL-2 release and CD25 surface expression following TCR-independent activation. Mechanistically, inhibition of the active pool of SFKs induced nuclear translocation of NFAT1, and enhanced NFAT1-dependent signaling in resting T cells. The negative regulation of NFAT1 signaling was in part mediated by the Src-kinase Lck as human T cells lacking Lck had increased levels of nuclear NFAT1 and demonstrated enhanced NFAT1-dependent gene expression. Inhibition of active SFKs in resting primary human T cells also increased nuclear NFAT1 and enhanced NFAT1-dependent signaling. Finally, the calcineurin inhibitor FK506 and Cyclosporin A reversed the effect of SFKs inhibition on NFAT1. Together, these data identified a novel role of SFKs in preventing aberrant NFAT1 activation in resting T cells, and suggest that maintaining this pool of active SFKs in therapeutic T cells may increase the efficacy of T cell therapies.

Correlation and cluster analysis of immunomodulatory drugs based on cytokine profiles

Drug discovery is a constant struggle to overcome hurdles posed by the complexity of biological systems. One of these hurdles is to find and understand the molecular target and the biological mechanism of action. Although the molecular target has been determined, the true biological effect may be unforeseen also for well-established drugs. Hence, there is a need for novel ways to increase the knowledge of the biological effects of drugs in the developmental process. In this study, we have determined cytokine profiles for 26 non-biological immunomodulatory drugs or drug candidates and used these profiles to cluster the compounds according to their effect in a preclinical ex vivo culture model of arthritis. This allows for prediction of functions and drug target of a novel drug candidate based on profiles obtained in this study. Results from the study showed that the JAK inhibitors tofacitinib and ruxolitinib formed a robust cluster and were found to have a distinct cytokine profile compared to the other drugs. Another robust cluster included the calcineurin inhibitors cyclosporine A and tacrolimus and the protein kinase inhibitors fostamatinib disodium and sotrastaurin acetate, which caused a strong overall inhibition of the cytokine production. The results of this methodology indicate that cytokine profiles can be used to provide a fingerprint-like identification of a drug as a tool to benchmark novel drugs and to improve descriptions of mode of action.

Inhibition of Calcineurin or IMP Dehydrogenase Exerts Moderate to Potent Antiviral Activity against Norovirus Replication.

Norovirus is a major cause of acute gastroenteritis worldwide and has emerged as an important issue of chronic infection in transplantation patients. Since no approved antiviral is available, we evaluated the effects of different immunosuppressants and ribavirin on norovirus and explored their mechanisms of action by using a human norovirus (HuNV) replicon-harboring model and a surrogate murine norovirus (MNV) infectious model. The roles of the corresponding drug targets were investigated by gain- or loss-of-function approaches. We found that the calcineurin inhibitors cyclosporine (CsA) and tacrolimus (FK506) moderately inhibited HuNV replication. Gene silencing of their cellular targets, cyclophilin A, FKBP12, and calcineurin, significantly inhibited HuNV replication. A low concentration, therapeutically speaking, of mycophenolic acid (MPA), an uncompetitive IMP dehydrogenase (IMPDH) inhibitor, potently and rapidly inhibited norovirus replication and ultimately cleared HuNV replicons without inducible resistance following long-term drug exposure. Knockdown of the MPA cellular targets IMPDH1 and IMPDH2 suppressed HuNV replication. Consistent with the nucleotide-synthesizing function of IMPDH, exogenous guanosine counteracted the antinorovirus effects of MPA. Furthermore, the competitive IMPDH inhibitor ribavirin efficiently inhibited norovirus and resulted in an additive effect when combined with immunosuppressants. The results from this study demonstrate that calcineurin phosphatase activity and IMPDH guanine synthase activity are crucial in sustaining norovirus infection; thus, they can be therapeutically targeted. Our results suggest that MPA shall be preferentially considered immunosuppressive medication for transplantation patients at risk of norovirus infection, whereas ribavirin represents as a potential antiviral for both immunocompromised and immunocompetent patients with norovirus gastroenteritis.

The fungal neurotoxin penitrem A induces the production of reactive oxygen species in human neutrophils at submicromolar concentrations

Penitrem A is a fungal neurotoxin that recurrently causes intoxication in animals, and occasionally also in humans. We have previously reported that penitrem A induced the production of reactive oxygen species (ROS) in rat cerebellar granule cells, opening for a new mechanism of action for the neurotoxin. The aim of this study was to examine the potential of penitrem A to induce ROS production in isolated human neutrophil granulocytes, and to study possible mechanisms involved.Penitrem A significantly increased the production of ROS in human neutrophils at concentrations as low as 0.25μM (40% increase over basal levels), as measured with the DCF fluorescence assay. The EC50 determined for the production of ROS by penitrem A was 3.8μM. The maximal increase in ROS production was approximately 330% over basal levels at a concentration of 12.5μM. ROS formation was significantly inhibited by the antioxidant vitamin E (50μM), the intracellular Ca+2 chelator BAPTA-AM (5μM), the mitogen activated protein kinase kinase (MEK) 1/2 and 5 inhibitor U0126 (1 and 10μM), the p38 mitogen activated protein kinase (MAPK) inhibitor SB203580 (1μM), the c-Jun amino-terminal kinase (JNK) inhibitor SP600125 (10μM), and the calcineurin inhibitors FK-506 and cyclosporine A (1.5 and 0.5μM, respectively).These finding suggest that penitrem A is able to induce an increase in ROS production in neutrophils via the activation of several MAPK-signalling pathways. We suggest that this increase may partly explain the pathophysiology generated by penitrem A neuromycotoxicosis in both humans and animals.

Leki immunomodulujące – farmakokinetyka, interakcje i objawy niepożądane

Supresja układu immunologicznego jest podstawą leczenia wielu lokalnych i układowych chorób autoimmunizacyjnych. Przewlekłe stosowanie kortykosteroidów wiąże się z klinicznie istotnymi powikłaniami, co było powodem poszukiwania leków immunosupresyjnych zastępujących kortykosteroidy. Głównym działaniem leków immunomodulujących jest hamowanie proliferacji limfocytów na drodze różnych mechanizmów – alkilujących (cyklofosfamid, chlorambucyl), antymetabolicznych (tiopuryny, metotreksat, mykofenolan mofetylu) lub hamowania kalcyneuryny (cyklosporyna, takrolimus, ewerolimus). Przedstawiono przegląd wiedzy na temat farmakodynamiki, efektów niepożądanych i interakcji lekowych tiopuryn i metotreksatu – konwencjonalnych immunomodulatorów stosowanych w leczeniu nieswoistych zapaleń jelit.

Thrombotic microangiopathy associated with Valproic acid toxicity

BackgroundThrombotic microangiopathy (TMA) is a serious, sometimes life-threatening disorder marked by the presence of endothelial injury and microvascular thrombi. Drug-induced thrombotic microangiopathy (DI-TMA) is one specific TMA syndrome that occurs following drug exposure via drug-dependent antibodies or direct tissue toxicity. Common examples include calcineurin inhibitors Tacrolimus and Cyclosporine and antineoplastics Gemcitabine and Mitomycin. Valproic acid has not been implicated in DI-TMA. We present the first case of a patient meeting clinical criteria for DI-TMA following admission for valproic acid toxicity.Case presentationAn adolescent male with difficult to control epilepsy was admitted for impaired hepatic function while on valproic acid therapy. On the third hospital day, he developed severe metabolic lactic acidosis and multiorgan failure, prompting transfer to the pediatric intensive care unit. Progressive anemia and thrombocytopenia instigated an evaluation for thrombotic microangiopathy, where confirmed by concomitant hemolysis, elevated lactate dehydrogenase (LDH), low haptoglobin, and concurrent oliguric acute kidney injury. Thrombotic thrombocytopenic purpura was less likely with adequate ADAMTS13. Discontinuing valproic acid reversed the anemia, thrombocytopenia, and normalized the LDH and haptoglobin, supporting a drug-induced cause for the TMA.ConclusionTo the best of our knowledge, this is the first report of drug-induced TMA from valproic acid toxicity.

Honokiol inhibits c-Met-HO-1 tumor-promoting pathway and its cross-talk with calcineurin inhibitor-mediated renal cancer growth

Honokiol (HNK) is a small molecule with potent anti-inflammatory and anti-tumorigenic properties; yet the molecular targets of HNK are not well studied. Hyperactivation of the receptor tyrosine kinase c-Met and overexpression of the cytoprotective enzyme heme oxygenase-1 (HO-1) play a critical role in the growth and progression of renal cell carcinoma (RCC). Interestingly, the calcineurin inhibitor (CNI) cyclosporine A (CsA), an immunosuppressant used to prevent allograft rejection, can also increase the risk of RCC in transplant patients. We studied the potential role of c-Met signaling axis on CNI-induced renal tumor growth and tested the anti-tumor efficacy of HNK. Importantly, CNI treatment promoted c-Met induction and enhanced c-Met-induced Ras activation. We found that HNK treatment effectively down-regulated both c-Met phosphorylation and Ras activation in renal cancer cells. It inhibited the expression of both c-Met- and CNI-induced HO-1, and promoted cancer cell apoptosis. In vivo, HNK markedly inhibited CNI-induced renal tumor growth; and it decreased the expression of phospho-c-Met and HO-1 and reduced blood vessel density in tumor tissues. Our results suggest a novel mechanism(s) by which HNK exerts its anti-tumor activity through the inhibition of c-Met-Ras-HO-1 axis; and it can have significant therapeutic potential to prevent post-transplantation cancer in immunosuppressed patients.