Immunosuppressive calcineurin inhibitor cyclosporine A induces proapoptotic endoplasmic reticulum stress in renal tubular cells

NLRP3 inflammasome: structure, mechanism, drug-induced organ toxicity, therapeutic strategies, and future perspectives

Drug-induced toxicity is an important issue in clinical medicine, which typically results in organ dysfunction and adverse health consequences. The family of NOD-like receptors (NLRs) includes intracellular proteins involved in recognizing pathogens and triggering innate immune responses, including the activation of the NLRP3 inflammasome. The NLRP3 (nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3) inflammasome is a critical component for both innate and adaptive immune responses and has been implicated in various drug-induced toxicities, including hepatic, renal, and cardiovascular diseases. The unusual activation of the NLRP3 inflammasome causes the release of pro-inflammatory cytokines, such as IL-1β and IL-18, which can lead to more damage to tissues. Targeting NLRP3 inflammasome is a potential therapeutic endeavour for suppressing drug-induced toxicity. This review provides insights into the mechanism, drug-induced organ toxicity, therapeutic strategies, and prospective therapeutic approaches of the NLRP3 inflammasome and summarizes the developing therapies that target the inflammasome unit. This review has taken up one of the foremost endeavours in understanding and inhibiting the NLRP3 inflammasome as a means of generating safer pharmacological therapies.

A comparative analysis of drug-induced kidney injury adverse reactions between cyclosporine and tacrolimus based on the FAERS database

BACKGROUND

This study utilizes the FDA Adverse Event Reporting System (FAERS) database to compare the adverse reaction signals of cyclosporine and tacrolimus, two widely used immunosuppressants, in relation to drug-induced kidney injury. The findings aim to inform clinical decision-making.

METHODS

The study retrospectively analyzed data from January 2004 to September 2024, employing both frequency analysis and Bayesian methods. We assessed and compared the mortality rates, hospitalization rates, and the association of cyclosporine and tacrolimus with kidney injury to elucidate the renal toxicity of these two drugs.

RESULTS

After data processing, we identified a total of 3,449 cyclosporine-related kidney injury reports and 5,538 tacrolimus-related kidney injury reports. The results revealed a stronger association between tacrolimus and kidney injury. Additionally, kidney injuries associated with both cyclosporine and tacrolimus predominantly affected males. Furthermore, the hospitalization rate for cyclosporine-related kidney injury was 34.40%, compared to 44.50% for tacrolimus. The mortality rate associated with cyclosporine-induced kidney injury was higher than that of tacrolimus.

CONCLUSION

This study utilized the FDA Adverse Event Reporting System (FAERS) database from January 2004 to September 2024 to perform a comprehensive analysis of adverse drug-related kidney injury reactions to cyclosporine and tacrolimus. The results suggest that both cyclosporine and tacrolimus are associated with renal injury, but tacrolimus appears to reduce mortality while increasing hospitalization rates. This serves as a critical warning for planning future treatment regimens, drug monitoring, and reducing adverse effects.

TNF inhibits NKCC2 phosphorylation by a calcineurin-dependent pathway

We previously demonstrated that tumor necrosis factor-alpha (TNF) inhibits Na+-K+-2Cl- cotransporter (NKCC2) phosphorylation in the thick ascending limb (TAL); however, the underlying mechanism remains unclear. We tested the hypothesis that the induction of calcineurin (CN) activity and the expression of CN isoforms contribute to the mechanism by which TNF inhibits phospho-NKCC2 (pNKCC2) expression. CN activity increased by approximately twofold in primary cultures of medullary (m)TAL cells challenged with mouse recombinant TNF. In contrast, silencing TNF production in mTAL cells using lentivirus U6-TNF-ex4 reduced CN activity. pNKCC2 expression decreased in mTAL cells challenged with TNF, whereas inhibition of CN activity with cyclosporine A (CsA) increased pNKCC2 expression. Although mTAL cells express both the calcineurin A subunit (CNA) α and β isoforms, only CNA β isoform mRNA increased after mTAL cells were challenged with TNF. In vivo, both TNF and CNA β expression increased in outer medulla (OM) from mice given 1% NaCl in the drinking water for 7 days and intrarenal lentivirus silencing of TNF selectively reduced expression of CNA β. Intrarenal injection of a lentivirus that specifically silenced CNA β (U6-CNAβ-ex6) increased pNKCC2 expression and attenuated the inhibitory effects of TNF on pNKCC2 expression in freshly isolated TAL tubules. Collectively, the study is the first to demonstrate that TNF increases CN activity and specifically induces β-isoform expression in the kidney. Since NKCC2 is a known target of the CNA β isoform, these findings suggest that a CN-dependent signaling pathway involving this isoform contributes to the mechanism by which TNF inhibits pNKCC2 expression.NEW & NOTEWORTHY The beneficial immunosuppressive effects of CsA are tempered by renal side effects including reduction of GFR, proximal tubule damage, reduced urinary concentration, fibrosis and hypertension. As chronic administration of CN inhibitors frequently induce hypertension and renal nephropathy in humans, understanding the molecular mechanisms by which CN isoforms regulate the activity of renal transporters may provide the framework for developing new drugs that more selectively modulate the diverse functions of CN.

Chronic Antibody-Mediated Rejection and Plasma Cell ER Stress: Opportunities and Challenges with Calcineurin Inhibitors

Chronic alloantibody-mediated rejection (cAMR) remains a major challenge in transplant immunology, with no FDA-approved targeted therapies currently available. Despite advancements in cellular immunosuppression, effective strategies to mitigate alloantibody-mediated rejection are still lacking. This review provides a comprehensive overview of transplant rejection with a particular focus on the pathophysiology and therapeutic landscape of cAMR. We highlight the role of plasma cell-driven alloantibody production and its susceptibility to endoplasmic reticulum (ER) stress, a pathway with potential for therapeutic intervention. Special attention is given to calcineurin inhibitors (CNIs), which, beyond their well-established T-cell inhibitory effects, exhibit differential impacts on ER stress and plasma cell viability. By delineating the mechanistic differences between cyclosporine and tacrolimus in regulating ER stress responses, we propose potential therapeutic implications for optimizing cAMR management. This review underscores the need for innovative strategies targeting plasma cell biology to improve long-term transplant outcomes.

A comprehensive review of the clinical presentation, diagnosis, and treatment of calcineurin inhibitor-induced pain syndrome

Calcineurin inhibitor-induced pain syndrome (CIPS), a rare but recognized complication of calcineurin inhibitor (CNI) therapy in transplant recipients, presents as severe bilateral lower extremity pain. This syndrome, first described in 1989, primarily affects patients receiving tacrolimus or cyclosporine. Proposed mechanisms include intraosseous vasoconstriction, bone marrow edema, and altered bone metabolism, possibly involving TRSK channels and NFAT signaling. The diagnosis relies on clinical history, characteristic pain patterns, and imaging findings such as bone marrow edema on MRI. The management of CIPS revolves around reducing or discontinuing the offending CNI while maintaining immunosuppression. Alternative immunosuppressants like mammalian target rapamycin (mTOR) inhibitors or mycophenolate mofetil are considered to mitigate symptoms. Symptomatic relief includes calcium channel blockers, bisphosphonates, and analgesics like NSAIDs or opioids. Physical therapy and close monitoring are also integral to improving outcomes and managing chronic pain effectively in affected transplant recipients. This review synthesizes current knowledge on CIPS, highlighting diagnostic challenges, treatment options, and areas for future research to optimize clinical management and enhance patient outcomes.

Kaempferol attenuates cyclosporine-induced renal tubular injury via inhibiting the ROS-ASK1-MAPK pathway

Cyclosporine (CSA) is a widely used immunosuppressive medication. CSA nephrotoxicity severely limits its application. Kaempferol (KPF), a naturally occurring phenolic compound, has a promising protective effect in reducing CSA-induced renal tubular injury, but the mechanism remains unknown. Our study aimed to determine the protective role of KPF against CSA-induced renal tubular injury. C57/B6 mice and the NRK-52E cell line were employed. CSA worsened renal function in mice, causing detachment and necrosis of tubular cells, leading to tubular vacuolation and renal interstitial fibrosis. CSA caused the detachment, rupture, and death of tubular cells in vitro, resulting in cell viability loss. KPF mitigated all these injurious alterations. KPF hindered CSA-induced ROS generation and protected renal tubular epithelial cells, similar to the antioxidant NAC. CSA lowered SOD activity and GSH levels while increasing MDA levels, and KPF ameliorated these changes. CSA caused phosphorylation of ASK1, JNK, and p38, similar to H2O2, whereas KPF significantly inhibited these changes. In conclusion, KPF reduces CSA-induced tubular epithelial cell injury via its antioxidant properties, inhibits the phosphorylation of ASK1, and inhibits the phosphorylation of p38 and JNK, implying that the synergistic use of KPF in CSA immunotherapy may be a promising option to reduce CSA-evoked renal injury.

Physalin F, a Potent Inhibitor of Lymphocyte Function, Is a Calcineurin Inhibitor and Has Synergistic Effect with Dexamethasone

The dysregulation of immune responses are responsible for the development of several diseases, such as allergic and autoimmune diseases. The medications used to treat these conditions have numerous side effects, creating the need for new drugs. Physalins are natural compounds with various pharmacological activities already described. Here, we aimed to investigate the immunomodulatory effects of physalin F in mouse splenocytes and in a delayed-type hypersensitivity (DTH) model. In a cytotoxicity assay, physalin F had low cytotoxicity to mouse splenocytes in concentrations equal to or below 2 µM. It significantly inhibited lymphocyte proliferation in a concentration-dependent manner and reduced the production of cytokines, including IL-2, IL-4, IL-10, and IFN-γ, in activated splenocytes. The combined therapy of physalin F with dexamethasone was investigated in vitro, showing a synergistic action of the two compounds. Mechanistically, physalin F reduced calcineurin activity in concanavalin A-stimulated splenocyte cultures. Finally, in vivo, the intraperitoneal administration of physalin F in a DTH model reduced paw edema induced by bovine serum albumin immunization. Our results demonstrate the potential of physalin F as an immunosuppressive agent, to be used alone or in combination with glucocorticoids.

In Vitro Assessment of Fluconazole and Cyclosporine A Antifungal Activities: A Promising Drug Combination Against Different Candida Species

Invasive candidiasis is a common fungal infection associated with multiple risk factors, such as cancer, neutropenia, corticosteroid therapy, catheterization, and the use of broad-spectrum antibiotic treatment. Candida albicans is the predominant causative agent, although other Candida species have been emerging in the last years, together with a rise in a number of strains resistant to the currently available antifungal drugs, which poses a challenge when treating these infections. Drug repurposing and drug combinations are promising strategies for the treatment of invasive mycoses. In this study, we evaluated the effect of the combination of fluconazole (FLZ) and cyclosporine A (CsA) against 39 clinical isolates and reference strains of Candida. Two methods, the Loewe additivity model and Bliss independence model, were used to assess the antifungal activity of the drug combination according to CLSI and EUCAST guidelines. The results demonstrated a synergistic effect between fluconazole (FLZ) and cyclosporine A (CsA) against 15-17 Candida isolates, depending on the evaluation model used, including FLZ-resistant strains of C. albicans, C. glabrata, C. parapsilosis, and C. tropicalis. Notably, the combination significantly reduced the minimum inhibitory concentration (MIC) of FLZ in a substantial number of isolates, including those with resistance to FLZ. Additionally, time-kill curve studies confirmed the synergistic interaction, further validating the potential of this combination as an alternative therapeutic strategy for candidiasis treatment. These findings emphasize the importance of investigating innovative drug combinations to address the challenges posed by antifungal resistance and improve treatment options for invasive fungal infections.

The safety of cyclosporine and tacrolimus in pediatric nephrotic syndrome patients: a disproportionate analysis based on the FAERS database

Objective

This study aimed to systematically evaluate the safety of cyclosporine (CsA) and tacrolimus (TAC) in pediatric nephrotic syndrome (NS) patients using real-world data from the FDA Adverse Event Reporting System (FAERS).

Methods

We analyzed adverse event (AE) reports from the FAERS database between Q4 2003 and Q2 2024, focusing on AEs associated with CsA and TAC in NS patients aged 18 years and younger. We employed three signal detection methods-Proportional Reporting Ratio (PRR), Relative Reporting Ratio (RRR), and Reporting Odds Ratio (ROR)-to assess the risk of drug-related AEs. Sensitivity analyses were conducted to explore the influence of gender on AE occurrence.

Results

A total of 207 CsA-related and 145 TAC-related AE reports were included. CsA was significantly associated with nephropathy toxic (ROR = 8.26, 95% CI: 4.21-16.20), urine output decreased (ROR = 29.93, 95% CI: 3.66-244.61), and posterior reversible encephalopathy syndrome (ROR = 6.70, 95% CI: 3.17-14.14). TAC was associated with an increased risk of dystonia (ROR = 67.93, 95% CI: 8.63-534.86), kidney fibrosis (ROR = 22.65, 95% CI: 8.16-62.87), and diabetic ketoacidosis (ROR = 46.51, 95% CI: 5.68-380.97). Sensitivity analysis indicated that gender influenced the occurrence of AEs, with CsA showing higher nephrotoxicity in male patients, while TAC was more strongly associated with metabolic disorders and neurological AEs in female patients.

Conclusion

In pediatric NS patients, CsA primarily induces nephrotoxicity and neurological complications, whereas TAC is more likely to cause kidney fibrosis and metabolic disorders. Enhanced monitoring of these AEs and individualized drug adjustments based on patient characteristics are recommended to optimize treatment outcomes and reduce AE incidence.

Thrombin confers chemotherapeutic resistance by promoting transcriptional induction and post-translational stabilization of pro-survival MCL1 in TNBC

The association between idiopathic venous thrombosis and occult cancer is widely recognized. However, the comprehensive understanding of how thrombin, generated during the process of thrombosis, possesses the potential to augment the malignant phenotype is still not well understood. The coagulation protease thrombin mediates its effects by cleaving protease-activated receptor 1 (PAR1), a receptor abundantly expressed on the surface of triple-negative breast cancer (TNBC) cells. While emerging evidence implicates coagulation proteases in facilitating cancer progression, the precise molecular pathways underlying thrombin-mediated induction of chemoresistance remain poorly defined. Here, we demonstrate that thrombin-induced PAR1 activation in TNBC cells promotes the development of a multidrug-resistant phenotype, mechanistically linked to the upregulation of the pro-survival protein MCL1. Genetic ablation of MCL1 sensitizes TNBC cells to cytotoxic drugs despite thrombin exposure, affirming MCL1's functional importance. Chromatin immunoprecipitation analyses reveal thrombin triggers protein kinase A-dependent phosphorylation of serine 133 residues of cAMP-responsive element-binding protein (CREB), enhancing CREB's affinity for the co-activators CBP and p300. Furthermore, thrombin treatment induces the nuclear translocation of CREB-regulated transcription coactivator 2 (CRTC2) in a calcium-dependent manner, which collectively interacts with CREB/CBP-P300. The coordinated action of these transcriptional co-activators facilitates the transcriptional induction of MCL1. We further report that PAR1 activation augments MCL1 binding to the deubiquitinase USP9X, reducing MCL1 turnover. Our pre-clinical breast cancer murine model also shows that genetic deletion of PAR1 sensitizes breast cancer cells to chemotherapeutic drugs in vivo. Collectively, these findings emphasize the thrombin-PAR1 axis as a novel driver of chemoresistance. Utilizing FDA-approved oral anticoagulants for selective blocking of thrombin action may serve as a potential therapeutic adjunct for the treatment of triple-negative breast cancer.

Saudi National Clinical Practice Guidelines for Management of Adult Systemic Lupus Erythematosus

OBJECTIVE

To provide evidence-based clinical practice recommendations for managing Systemic Lupus Erythematosus (SLE) in Saudi Arabia.

METHODS

This EULAR-adapted national guideline in which a multidisciplinary task force utilized the modified Delphi method to develop 31 clinical key questions. A systematic literature review was conducted to update the evidence since the EULAR publication. After reaching a consensus agreement, two rounds of voting and group discussion were conducted to generate consolidated recommendations/ statements.

RESULTS

A significant number of patients in Saudi Arabia experience delays in accessing rheumatologists, highlighting the significance of timely referral to SLE specialists or rheumatologists to ensure accurate diagnosis and prompt treatment. The primary goal of Glucocorticoid (GC) therapy in SLE patients is to establish disease control with a minimum dose and duration. Steroid-sparing agent utilization facilitates steroid-sparing goals. Hydroxychloroquine is recommended for all SLE patients, though physicians must carefully monitor toxicity and prioritize regular medication adherence assessment. SLE management during pregnancy starts from preconception time by assessing disease activity, major organ involvement, hypercoagulability status, and concomitant diseases that may negatively impact maternal and fetal outcomes. Multidisciplinary care with close monitoring may optimize both maternal and fetal outcomes. For patients with antiphospholipid antibodies, low-dose aspirin prophylaxis is recommended. Also, Long-term anticoagulant medications are fundamental to prevent secondary antiphospholipid syndrome due to high thrombosis recurrence.

CONCLUSION

This Saudi National Clinical Practice guidelines for SLE management provide evidence- based recommendations and guidance for healthcare providers in Saudi Arabia who are managing patients with SLE. These guidelines will help to standardize healthcare service, improve provider education, and perhaps lead to better treatment outcomes for SLE patients.

The tradeoff between the efficacy of calcineurin inhibitors: prevention of allograft rejection vs. post-transplant renal and cardiovascular complications

Solid organ transplantation has emerged as a crucial intervention in the field of medicine. During transplantation, our human body perceives the organ as an exogenous entity or graft, initiating an immune reaction to eliminate it. This immune response ultimately culminates in the rejection of the graft. So, to mitigate the possibility of graft rejection, implementing immune suppression is imperative. In this context, the utilization of calcineurin inhibitors (CNIs) assumes a pivotal role. Calcineurin inhibitors significantly preserve immunosuppression following solid organ transplantation. Calcineurin inhibitors have considerably improved short-term results in renal transplantation by reducing acute rejection rates. Concerning the limited therapeutic window of these medications, careful monitoring of pharmacological treatment and individual doses is required. However, a significant number of patients do experience CNI toxicity. Side effects of CNIs include renal failure, hypertension, respiratory disorders, gastrointestinal damage, gingivitis, and so on. Higher trough level of the drug causes acute nephrotoxicity, which is of three types: functional toxicity, tubular toxicity, and vascular toxicity. Acute nephrotoxicity, if untreated, leads to irreversible, progressive deterioration of allograft function, leading to chronic nephrotoxicity. Cardiovascular toxicity of CNIs includes atrial hypertension caused by vasoconstriction of the afferent arteriole, vascular remodeling, hypertrophy, dyslipidemia, and also the onset of diabetes. Such clinical complications further affect the patient's survivability and subjective well-being, possibly leading to graft loss. This review focuses on the most severe side effects of CNIs: renal and cardiovascular toxicity.

Usp9x contributes to the development of sepsis-induced acute kidney injury by promoting inflammation and apoptosis in renal tubular epithelial cells via activation of the TLR4/nf-κb pathway

As a pattern recognition receptor, Toll-like receptor 4 (TLR4) is crucial for the development and progression of acute kidney injury (AKI). This study aims to explore whether the deubiquitinase Usp9x influences the TLR4/NF-B pathway to cause sepsis-induced acute kidney injury (S-AKI). The model of AKI was established in Sprague-Dawley rats using the cecal ligation and puncture (CLP) method, while renal tubular epithelial cell NRK-52E was stimulated with lipopolysaccharide (LPS) in vitro. All plasmids were transfected into NRK-52E cells according to the indicated group. The deubiquitinase of TLR4 was predicted by the online prediction software Ubibrowser. Subsequently, Western blot and Pearson correlation analysis identified Usp9x protein as a potential candidate. Co-IP analysis verified the interaction between TLR4 and Usp9x. Further research revealed that overexpression of Usp9x inhibited degradation of TLR4 protein by downregulating its ubiquitination modification levels. Both in vivo and in vitro experiments observed that interference with Usp9x effectively alleviated the inflammatory response and apoptosis of renal tubular epithelial cells (RTECs) induced by CLP or LPS, whereas overexpression of TLR4 reversed this situation. Transfection with sh-Usp9x in NRK-52E cells suppressed the expression of proteins associated with the TLR4/NF-κB pathway induced by LPS. Moreover, the overexpression of TLR4 reversed the effect of sh-Usp9x transfection. Therefore, the deubiquitinase Usp9x interacts with TLR4, leading to the upregulation of its expression through deubiquitination modification, and the activation of the TLR4/NF-κB signaling pathway, thereby promoting inflammation and apoptosis in renal tubular epithelial cells and contributing to sepsis-induced acute kidney injury.

Enhanced IGF-IIRα Expression Exacerbates Lipopolysaccharide-Induced Cardiac Inflammation, Hypertrophy, and Apoptosis Through Calcineurin Activation

Cardiovascular disease is one of the leading causes of death worldwide and has a high prevalence. Insulin-like growth factor-II receptor α (IGF-IIRα) acts as a stress-inducible negative regulator. This study focused on the substantial impact of heightened expression of IGF-IIRα in cardiac myoblasts and its association with the exacerbation of cardiac dysfunction. Using lipopolysaccharide (LPS)-induced H9c2 cardiac myoblasts as a model for sepsis, we aimed to elucidate the molecular interactions between IGF-IIRα and LPS in exacerbating cardiac injury. Our findings demonstrated a synergistic induction of cardiac inflammation and hypertrophy by LPS stimulation and IGF-IIRα overexpression, leading to decreased cell survival. Excessive calcineurin activity, triggered by this combined condition, was identified as a key factor exacerbating the negative effects on cell survival. Cellular changes such as cell enlargement, disrupted actin filaments, and upregulation of hypertrophy-related and inflammation-related proteins contributed to the overall hypertrophic and inflammatory responses. Overexpression of IGF-IIRα also exacerbated apoptosis induced by LPS in H9c2 cardiac myoblasts. Inhibiting calcineurin in LPS-treated H9c2 cardiac myoblasts with IGF-IIRα overexpression effectively reversed the detrimental effects, reducing cell damage and mitigating apoptosis-related cardiac mechanisms. Our study suggests that under sepsis-like conditions in the heart with IGF-IIRα overexpression, hyperactivation of calcineurin worsens cardiac damage. Suppressing IGF-IIRα and calcineurin expression could be a potential intervention to alleviate the impact of the illness and improve cardiac function.

Immunosuppression with cyclosporine versus tacrolimus shows distinctive nephrotoxicity profiles within renal compartments

AIM

Calcineurin inhibitors (CNIs) are the backbone for immunosuppression after solid organ transplantation. Although successful in preventing kidney transplant rejection, their nephrotoxic side effects contribute to allograft injury. Renal parenchymal lesions occur for cyclosporine A (CsA) as well as for the currently favored tacrolimus (Tac). We aimed to study whether chronic CsA and Tac exposures, before reaching irreversible nephrotoxic damage, affect renal compartments differentially and whether related pathogenic mechanisms can be identified.

METHODS

CsA and Tac were administered chronically in wild type Wistar rats using osmotic minipumps over 4 weeks. Functional parameters were controlled. Electron microscopy, confocal, and 3D-structured illumination microscopy were used for histopathology. Clinical translatability was tested in human renal biopsies. Standard biochemical, RNA-seq, and proteomic technologies were applied to identify implicated molecular pathways.

RESULTS

Both drugs caused significant albeit differential damage in vasculature and nephron. The glomerular filtration barrier was more affected by Tac than by CsA, showing prominent deteriorations in endothelium and podocytes along with impaired VEGF/VEGFR2 signaling and podocyte-specific gene expression. By contrast, proximal tubule epithelia were more severely affected by CsA than by Tac, revealing lysosomal dysfunction, enhanced apoptosis, impaired proteostasis and oxidative stress. Lesion characteristics were confirmed in human renal biopsies.

CONCLUSION

We conclude that pathogenetic alterations in the renal compartments are specific for either treatment. Considering translation to the clinical setting, CNI choice should reflect individual risk factors for renal vasculature and tubular epithelia. As a step in this direction, we share protein signatures identified from multiomics with potential pathognomonic relevance.

Calcineurin inhibitor-related hyperkalemia is caused by hyporeninemic hypoaldosteronism and fludrocortisone is an effective treatment: Report of a case series and review of the literature

INTRODUCTION

Calcineurin inhibitors (CNIs) are widely used in transplantation. Although CNI-related hyperkalemia is common (10%-60.6%), the underlying pathogenetic mechanism is not well-elucidated and may lead to dose adjustment or treatment withdrawal.

OBJECTIVE

The aim of this study is to describe CNI-related hyperkalemia due to hyporeninemic hypoaldosteronism in pediatric transplant recipients who were successfully treated with fludrocortisone.

METHOD

In a total of 55 hematopoietic stem cell (HSCT) and 35 kidney transplant recipients followed according to institutional immunosuppression protocols, recipients diagnosed with CNI-related hyperkalemia were reviewed. Recipients who were receiving intravenous fluid, potassium, or were diagnosed with hemolysis, acute graft rejection, or had an eGFR < 30 mL/min/1.73m2, were excluded. A detailed analysis of clinical history as well as biochemical studies was carried out to reveal possible pathophysiology.

RESULTS

Three pediatric transplant recipients (one HSCT, two kidney transplantation) with findings of hyperkalemia, hyponatremia, and a mild elevation in blood urea nitrogen while on CNIs were recruited. Urinary potassium excretion was diminished while sodium excretion was increased. Plasma aldosterone levels were low, and renin was not increased in response. Primary adrenal insufficiency was ruled out, and hyporeninemic hypoaldosteronism was diagnosed. CNI-related hyperkalemia was detected earlier in case 1, who had HSCT (22 days), than in the second and third cases, who had kidney transplantation (24 and 30 months post-transplantation, respectively). The discrepancy was hypothesized to be explained by higher overall CNI dose due to higher serum target CNI used in HSCT than kidney transplantation. Electrolyte imbalance was reversed upon administration of physiologic dose fludrocortisone (0.05 mg, daily), while fludrocortisone was ceased after CNI withdrawal in case 1, which is additional evidence for the etiological association of CNIs and hyporeninemic hypoaldosteronism.

CONCLUSION

Our three cases strengthen the premise that CNI-related hyperkalemia may be due to hyporeninemic hypoaldosteronism, and the timing and severity may be related to CNI dose. Fludrocortisone is a safe and effective treatment in CNI-related hyperkalemia, providing maintenance of CNIs, which are one of the essential therapeutic agents for pediatric transplantation.

The First Reciprocal Activities of Chiral Peptide Pharmaceuticals: Thymogen and Thymodepressin, as Examples

Peptides show high promise in the targeting and intracellular delivery of next-generation biotherapeutics. The main limitation is peptides' susceptibility to proteolysis in biological systems. Numerous strategies have been developed to overcome this challenge by chemically enhancing the resistance to proteolysis. In nature, amino acids, except glycine, are found in L- and D-enantiomers. The change from one form to the other will change the primary structure of polypeptides and proteins and may affect their function and biological activity. Given the inherent chiral nature of biological systems and their high enantiomeric selectivity, there is rising interest in manipulating the chirality of polypeptides to enhance their biomolecular interactions. In this review, we discuss the first examples of up-and-down homeostasis regulation by two enantiomeric drugs: immunostimulant Thymogen (L-Glu-L-Trp) and immunosuppressor Thymodepressin (D-Glu(D-Trp)). This study shows the perspective of exploring chirality to remove the chiral wall between L- and D-biomolecules. The selected clinical result will be discussed.

Consensus on the therapeutic management of atopic dermatitis ‒ Brazilian Society of Dermatology: an update on phototherapy and systemic therapy using e-Delphi technique

This publication is an update of the "Consensus on the therapeutic management of atopic dermatitis - Brazilian Society of Dermatology" published in 2019, considering the novel, targeted-oriented systemic therapies for atopic dermatitis. The initial recommendations of the current consensus for systemic treatment of patients with atopic dermatitis were based on a recent review of scientific published data and a consensus was reached after voting. The Brazilian Society of Dermatology invited 31 experts from all regions of Brazil and 2 international experts on atopic dermatitis who fully contributed to the process. The methods included an e-Delphi study to avoid bias, a literature search and a final consensus meeting. The authors added novel approved drugs in Brazil and the indication for phototherapy and systemic therapy for AD. The therapeutical response to systemic treatment is hereby reported in a suitable form for clinical practice and is also part of this updated manuscript.

Avocado Seeds-Mediated Alleviation of Cyclosporine A-Induced Hepatotoxicity Involves the Inhibition of Oxidative Stress and Proapoptotic Endoplasmic Reticulum Stress

Previous studies reported disrupted hepatic function and structure following the administration of cyclosporine A (CsA) in humans and animals. Recently, we found that avocado seeds (AvS) ameliorated CsA-induced nephrotoxicity in rats. As a continuation, herein we checked whether AvS could also attenuate CsA-induced hepatotoxicity in rats. Subcutaneous injection of CsA (5 mg/kg) for 7 days triggered hepatotoxicity in rats, as indicated by liver dysfunction, redox imbalance, and histopathological changes. Oral administration of 5% AvS powder for 4 weeks ameliorated CsA-induced hepatotoxicity, as evidenced by (1) decreased levels of liver damage parameters (alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and bilirubin), (2) resumed redox balance in the liver (reduced malondialdehyde (MDA) and increased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)), (3) downregulated hepatic expression of endoplasmic reticulum (ER) stress-related genes (X-box binding protein 1 (XBP1), binding immunoglobulin protein (BIP), C/EBP homologous protein (CHOP)), and apoptosis-related genes (Bax and Casp3), (4) upregulated expression of the anti-apoptotic gene Bcl2, (5) reduced DNA damage, and (6) improved liver histology. These results highlight the ability of AvS to ameliorate CsA-induced hepatotoxicity via the inhibition of oxidative stress and proapoptotic ER stress.

Demethylation of H3K9 and H3K27 Contributes to the Tubular Renal Damage Triggered by Endoplasmic Reticulum Stress

Loss of protein homeostasis (proteostasis) in the endoplasmic reticulum (ER) activates the unfolded protein response (UPR), restoring correct protein folding. Sustained ER stress exacerbates activation of the major UPR branches (IRE1α/XBP1, PERK/ATF4, ATF6), inducing expression of numerous genes involved in inflammation, cell death, autophagy, and oxidative stress. We investigated whether epigenetic dynamics mediated by histone H3K9 and H3K27 methylation might help to reduce or inhibit the exacerbated and maladaptive UPR triggered in tubular epithelial cells. Epigenetic treatments, specific silencing, and chromatin immunoprecipitation assays were performed in human proximal tubular cells subjected to ER stress. Pharmacological blockage of KDM4C and JMJD3 histone demethylases with SD-70 and GSKJ4, respectively, enhanced trimethylation of H3K9 and H3K27 in the ATF4 and XBP1 genes, inhibiting their expression and that of downstream genes. Conversely, specific G9a and EZH2 knockdown revealed increases in ATF4 and XBP1 expression. This is a consequence of the reduced recruitment of G9a and EZH2 histone methylases, diminished H3K9me3 and H3K27me3 levels, and enhanced histone acetylation at the ATF4 and XBP1 promoter region. G9a and EZH2 cooperate to maintain the repressive chromatin structure in both UPR-induced genes, ATF4 and XBP1. Therefore, preserving histone H3K9 and H3K27 methylation could ameliorate the ER stress, and consequently the oxidative stress and the triggered pathological processes that aggravate renal damage.

Mechanism of Endoplasmic Reticulum Stress Pathway in the Osteogenic Phenotypic Transformation of Aortic Valve Interstitial Cells

BACKGROUND AND PURPOSE

Calcific Aortic Valve Disease (CAVD) is a crucial component of degenerative valvular disease in old age and with the increasing prevalence of the aging population. we hope that by modeling valvular osteogenesis and intervening with endoplasmic reticulum stress inhibitor TUDCA to observe the effect of endoplasmic reticulum stress on valve osteogenesis.

METHODS

In this study, rabbit heart valvular interstitial cells (VICs) were isolated and cultured. They treated with ox-LDL (Oxidized Low Density Lipoprotein) stimulation to establish a model of valvular osteogenic transformation. BMP2 (Bone Morphogenetic Protein 2), PERK (Protein kinase R-like endoplasmic reticulum kinase), CHOP (CCAAT/enhancer-binding protein homologous protein) and transcriptional regulatory factor ATF4 (Activating Transcription Factor 4 )were recorded after intervention with ER stress inhibitor TUDCA. The effects of er stress on valvular osteogenic transformation were analyzed.

RESULT

After stimulation of VICs with ox-LDL, the expression levels of BMP2, PERK, CHOP, and ATF4 increased. However, TUDCA treatment can alleviate the increased expression levels of BMP2, PERK ATF4, and CHOP under ox-LDL stimulation to a certain extent.

CONCLUSION

The endoplasmic reticulum stress signaling pathway is involved in ox-LDL-induced calcification of rabbit valve interstitial cells. Inhibition of endoplasmic reticulum stress using TUDCA can improve the progression of rabbit aortic valve calcification.