Side effects of sirolimus

mTOR signaling is required for phagocyte free radical production, GLUT1 expression, and control of Staphylococcus aureus infection

Mammalian target of rapamycin (mTOR) is a key regulator of metabolism in the mammalian cell. Here, we show the essential role for mTOR signaling in the immune response to bacterial infection. Inhibition of mTOR during infection with Staphylococcus aureus revealed that mTOR signaling is required for bactericidal free radical production by phagocytes. Mechanistically, mTOR supported glucose transporter GLUT1 expression, potentially through hypoxia-inducible factor 1α, upon phagocyte activation. Cytokine and chemokine signaling, inducible nitric oxide synthase, and p65 nuclear translocation were present at similar levels during mTOR suppression, suggesting an NF-κB-independent role for mTOR signaling in the immune response during bacterial infection. We propose that mTOR signaling primarily mediates the metabolic requirements necessary for phagocyte bactericidal free radical production. This study has important implications for the metabolic requirements of innate immune cells during bacterial infection as well as the clinical use of mTOR inhibitors.IMPORTANCESirolimus, everolimus, temsirolimus, and similar are a class of pharmaceutics commonly used in the clinical treatment of cancer and the anti-rejection of transplanted organs. Each of these agents suppresses the activity of the mammalian target of rapamycin (mTOR), a master regulator of metabolism in human cells. Activation of mTOR is also involved in the immune response to bacterial infection, and treatments that inhibit mTOR are associated with increased susceptibility to bacterial infections in the skin and soft tissue. Infections caused by Staphylococcus aureus are among the most common and severe. Our study shows that this susceptibility to S. aureus infection during mTOR suppression is due to an impaired function of phagocytic immune cells responsible for controlling bacterial infections. Specifically, we observed that mTOR activity is required for phagocytes to produce antimicrobial free radicals. These results have important implications for immune responses during clinical treatments and in disease states where mTOR is suppressed.

Treatment of tuberous sclerosis complex manifestations in children with mTOR inhibitors

PURPOSE

Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic disorder that affects multiple organ systems. Mutations in the TSC1 and TSC2 genes result in the constitutive hyperactivation of the mammalian target of rapamycin (mTOR) pathway, contributing to the growth of benign tumors or hamartomas in various organs. Due to the implication of mTOR pathway dysregulation in the disease pathology, increasing evidence supports the use of mTOR inhibitors for treating multiple manifestations of TSC.

METHODS

In this study, we conducted a retrospective analysis of clinical findings and treatment data from 38 patients diagnosed with tuberous sclerosis who were followed up in the Pediatric Oncology Clinic between 2010 and 2020. We collected information on patients' ages, genders, affected sites, familial history, imaging findings, presence of tumors, and treatments.

RESULTS

Among the patients, nine individuals with TSC manifestations were treated with mTOR inhibitors. Specifically, everolimus was successfully administered to five patients with inborn cardiac rhabdomyoma causing hemodynamic impairment. In addition, two patients with refractory seizures received everolimus in combination with anti-epileptic drugs. A patient with renal angiomyolipomas larger than 3 cm was treated with everolimus, while a patient with extensive facial angiofibroma received topical sirolimus. All patients tolerated the mTOR inhibitors well, and the side effects were deemed acceptable.

CONCLUSION

The utilization of mTOR inhibition in TSC is expected to become more prevalent in clinical practice, as current research is anticipated to provide a better understanding of the therapeutic roles of these treatments in TSC.

Harnessing the multifunctionality of lipid-based drug delivery systems for the local treatment of osteoarthritis

Osteoarthritis (OA) is a widespread joint condition affecting millions globally, presenting a growing socioeconomic burden thus making the development of more effective therapeutic strategies crucial. This review emphasizes recent advancements in lipid-based drug delivery systems (DDSs) for intra-articular administration of OA therapeutics, encompassing non-steroidal anti-inflammatory drugs, corticosteroids, small molecule disease-modifying OA drugs, and RNA therapeutics. Liposomes, lipid nanoparticles, lipidic mesophases, extracellular vesicles and composite systems exhibit enhanced stability, targeted delivery, and extended joint retention, which contribute to improved therapeutic outcomes and minimized systemic drug exposure. Although active targeting strategies hold promise, further research is needed to assess their targeting efficiency in physiologically relevant conditions. Simultaneously, multifunctional DDSs capable of delivering combinations of distinct therapeutic classes offer synergistic effects and superior OA treatment outcomes. The development of such long-acting systems that resist rapid clearance from the joint space is crucial, where particle size and targeting capabilities emerge as vital factors. Additionally, combining cartilage lubrication properties with sustained drug delivery has demonstrated potential in animal models, meriting further investigation in human clinical trials. This review highlights the crucial need for direct, head-to-head comparisons of novel DDSs with standard treatments, particularly within the same drug class. These comparisons are essential in accurately evaluating their effectiveness, safety, and clinical applicability, and are set to significantly shape the future of OA therapy.

Treatment optimization of maintenance immunosuppressive agents in pediatric renal transplant recipients

Introduction: Graft survival in pediatric kidney transplant patients has increased significantly within the last three decades, correlating with the discovery and utilization of new immunosuppressants as well as improvements in patient care. Despite these developments in graft survival for patients, there is still improvement needed, particularly in long-term care in pediatric patients receiving grafts from deceased donor patients. Maintenance immunosuppressive therapies have narrow therapeutic indices and are associated with high inter-individual and intra-individual variability.Areas covered: In this review, we examine the impact of pharmacokinetic variability on renal transplantation and its association with age, genetic polymorphisms, drug-drug interactions, drug-disease interactions, renal insufficiency, route of administration, and branded versus generic drug formulation. Pharmacodynamics are outlined in terms of the mechanism of action for each immunosuppressant, potential adverse effects, and the utility of pharmacodynamic biomarkers.Expert opinion: Acquiring abetter quantitative understanding of immunosuppressant pharmacokinetics and pharmacodynamic components should help clinicians implement treatment regimens to maintain the balance between therapeutic efficacy and drug-related toxicity.

Normalization of Enzyme Expression and Activity Regulating Vitamin A Metabolism Increases RAR-Beta Expression and Reduces Cellular Migration and Proliferation in Diseases Caused by Tuberous Sclerosis Gene Mutations

Background

Mutation in a tuberous sclerosis gene (TSC1 or 2) leads to continuous activation of the mammalian target of rapamycin (mTOR). mTOR activation alters cellular including vitamin A metabolism and retinoic acid receptor beta (RARβ) expression. The goal of the present study was to investigate the molecular connection between vitamin A metabolism and TSC mutation. We also aimed to investigate the effect of the FDA approved drug rapamycin and the vitamin A metabolite retinoic acid (RA) in cell lines with TSC mutation.

Methods

Expression and activity of vitamin A associated metabolic enzymes and RARβ were assessed in human kidney angiomyolipoma derived cell lines, primary lymphangioleiomyomatosis (LAM) tissue derived LAM cell lines. RARβ protein levels were also tested in primary LAM lung tissue sections. TaqMan arrays, enzyme activities, qRT-PCRs, immunohistochemistry, immunofluorescent staining, and western blotting were performed and analysed. The functional effects of retinoic acid (RA) and rapamycin were tested in a scratch and a BrDU assay to assess cell migration and proliferation.

Results

Metabolic enzyme arrays revealed a general deregulation of many enzymes involved in vitamin A metabolism including aldehyde dehydrogenases (ALDHs), alcohol dehydrogenases (ADHs) and Cytochrome P450 2E1 (CYP2E1). Furthermore, RARβ downregulation was a characteristic feature of all TSC-deficient cell lines and primary tissues. Combination of the two FDA approved drugs -RA for acute myeloid leukaemia and rapamycin for TSC mutation- normalised ALDH and ADH expression and activity, restored RARβ expression and reduced cellular proliferation and migration.

Conclusion

Deregulation of vitamin A metabolizing enzymes is a feature of TSC mutation. RA can normalize RARβ levels and limit cell migration but does not have a significant effect on proliferation. Based on our data, translational studies could confirm whether combination of RA with reduced dosage of rapamycin would have more beneficial effects to higher dosage of rapamycin monotherapy meanwhile reducing adverse effects of rapamycin for patients with TSC mutation.

Efficacy and safety of sirolimus in patients with systemic lupus erythematosus: A systematic review and meta-analysis

BACKGROUND

Emerging evidence suggested a potential therapeutic role of targeting mTOR in the treatment of SLE. But most studies were observational studies with limited sample size or case reports.

OBJECTIVE

To evaluate the efficacy and safety of sirolimus in treatment of SLE by systematic review and meta-analysis.

METHODS

Systematic searches of Medline/PubMed, EMBASE, the Cochrane library and Scopus were performed. Original case reports, case series, observational studies and clinical trials reporting the efficacy or safety data on SLE patients treated with sirolimus were included. A random-effects meta-analysis was performed to calculate the pooled efficacy, when possible.

RESULTS

A total of 9 studies comprising 145 patients were identified. The exposure of sirolimus was 245.8 patient-years, with 1-3 mg/day adopted in majority studies. In 111 clinical active patients, the pooled decrease of SLEDAI, BILAG and prednisone dosage was 4.85 (95% CI 3.44-6.25), 1.98 (95% CI 0.23-3.74) and 13.17 mg/day (95% CI 0.71-25.63) respectively. 23 patients initiating sirolimus for active SLE yielded remission in 17 (73.9%) patients. In 22 quiescent lupus nephritis patients, 21 (95.5%) patients sustained remission. Hematological, mucocutaneous abnormalities and dyslipidemia were the most common adverse events. Early cessation due to side effects was reported in 9.28% (13/140) patients, most of the side effects were mild and recovered quickly after cessation.

CONCLUSIONS

Summary of the available datasets indicated sirolimus was promising and well-tolerated in the treatment of SLE. Further randomized controlled trials evaluating the potential benefits and risk of sirolimus in SLE are warranted.

Association of Delta-6-Desaturase Expression with Aggressiveness of Cancer, Diabetes Mellitus, and Multiple Sclerosis: A Narrative Review

Background: The phosphatidylinositol 3-kinase/ protein kinase B /mammalian target of rapamycin (PI3K/Akt/ mTOR) signaling regulates multiple cellular processes and organizes cell proliferation, survival, and differentiation with the available nutrients, in particular, fatty acids. Polyunsaturated fatty acids (PUFAs) are cytotoxic to cancer cells and play a critical role in the treatment of multiple sclerosis (MS) and diabetes mellitus (DM). PUFAs are produced in the body by desaturases and elongases from dietary essential fatty acids (EFAs), primarily involving delta-6-desaturase (D6D). D6D is a rate-limiting enzyme for maintaining many aspects of lipid homeostasis and normal health. D6D is important to recognize the mechanisms that regulate the expression of this enzyme in humans. A lower level of D6D was seen in breast tumors compared to normal tissues. Interestingly, the elevated serum level of D6D was seen in MS and DM, which explains the critical role of D6D in inflammatory diseases. Methods: We searched databases of PubMed, Web of Science (WOS), Google Scholar, Scopus and related studies by predefined eligibility criteria. We assessed their quality and extracted data. Results: Regarding the mTOR signaling pathway, there is remarkable contributions of many inflammatory diseases to attention to common metabolic pathways are depicted. Of course, we need to have the insights into each disorder and their pathological process. The first step in balancing the intake of EFAs is to prevent the disruption of metabolism and expression of the D6D enzyme. Conclusions: The ω6 and ω3 pathways are two major pathways in the biosynthesis of PUFAs. In both of these, D6D is a vital bifunctional enzyme desaturating linoleic acid or alpha-linolenic acid. Therefore, if ω6 and ω3 EFAs are given together in a ratio of 2: 1, the D6D expression will be down-regulated and normalized.

Local suture ligation-assisted percutaneous sclerotherapy for Kasabach-Merritt phenomenon-associated kaposiform haemangioendothelioma

Kaposiform haemangioendotheliomas (KHEs) complicated by the Kasabach-Merritt phenomenon (KMP) are rare and severe neoplastic lesions often associated with locally aggressive disease, consumption coagulopathy and high mortality rates. Current regimens have yet to achieve a satisfactory therapeutic effect. Thus, an effective and minimally invasive approach for treating complex KHE/KMP cases is necessary for clinical management. The present case series describes patients with KHE/KMP who underwent local suture ligation-assisted percutaneous sclerotherapy to minimise surgical trauma and ensure effective treatment. Between September 2015 and September 2017, 3 consecutive patients with KHE/KMP underwent staged local suture ligation-assisted percutaneous sclerotherapy. Of these patients, 2 presented with medical histories of corticosteroid treatment with unsatisfactory outcomes. The patients underwent a stepwise synthetic serial therapy programme consisting of percutaneous sclerotherapy and adjunctive pharmacotherapy accompanied by a suture ligation procedure. Clinical, radiological, pathological and laboratory data were analysed to evaluate the outcomes of the therapy. All patients were successfully managed with the proposed procedure. Significant relief of clinical symptoms and improvements in haematological indicators were achieved. No recurrence or complications were observed during regular follow-up (4, 19 and 28 months). In conclusion, local suture ligation-assisted percutaneous sclerotherapy was demonstrated to be a safe and effective treatment for KHE/KMP, being minimally invasive, involving simple manipulation and providing a clear treatment benefit in certain cases. Further studies involving larger sample sizes are required to thoroughly evaluate the procedure, which can potentially be used as a novel therapeutic option for KHE/KMP treatment.

Emerging Interventions for Elderly Patients-The Promise of Regenerative Medicine

The impressive increase in lifespan that occurred in the 20th century has driven a boom in age-associated degeneration resulting from senescence. Geriatric syndromes, such as sarcopenia and frailty, do not fall neatly into classical medical definitions of disease because they result from subtle declines in physiological function that occur over many years instead of specific organ-related pathology. These conditions have become more clinically prominent with the aging population and are the focus of research in regenerative medicine. Two major approaches are being pursued: the first targets specific organs that are adversely affected by senescence, and the second targets senescence pathways themselves, with the goal of favorably altering the affected physiology. This review will highlight a few examples of recent applications of both of these approaches to illustrate the potential of the application of a regenerative medicine approach to improve the quality of life and independence in older adults.

Longterm Data on Sirolimus Treatment in Patients with Lupus Nephritis

Objective.

To expand the limited longterm data on sirolimus treatment in patients with lupus nephritis (LN). Our pilot short-term data suggested efficacy of sirolimus treatment in these patients.

Methods.

We retrospectively reviewed 16 class III/IV/V patients with LN who have received prednisolone (PSL) and sirolimus either as initial or maintenance treatment.

Results.

Sixteen patients received sirolimus treatment (9 because of intolerance to standard immunosuppressants and 7 because of a history of malignancy) for 45.3 ± 36.5 months. In 5 patients, sirolimus and PSL were given as induction for active nephritis, and they showed improvements in proteinuria (2.8 ± 1.9 g/day at baseline, 0.1 ± 0.1 g/day after 36 mos, p = 0.011), anti-dsDNA (107.7 ± 91.9 IU/ml and 37.0 ± 55.4 IU/ml, respectively, p = 0.178), and C3 (54.8 ± 26.1 mg/dl and 86.3 ± 18.6 mg/dl, respectively, p = 0.081). Eleven patients received sirolimus and low-dose PSL as longterm maintenance, and they showed continued improvement in C3 (90.4 ± 18.1 mg/dl and 117.7 ± 25.1 mg/dl at commencement and after 36 mos, respectively, p = 0.025), stable renal function (estimated glomerular filtration rate 58.6 ± 25.8 ml/min and 63.0 ± 29.6 ml/min, respectively, p = 0.239), and proteinuria (0.8 ± 0.7 g/day and 0.7 ± 0.7 g/day respectively, p = 0.252). Renal flare occurred in 1 patient, and another patient who had stage 4 chronic kidney disease when sirolimus was started developed endstage renal failure after 27 months. Sirolimus was discontinued in 5 patients, in 4 cases related to drug side effects. Deterioration of dyslipidemia occurred in 4 patients, but was adequately controlled with statin therapy.

Conclusion.

The preliminary evidence suggests that sirolimus may serve as an alternative treatment for patients with LN who do not tolerate standard treatment or who had a history of malignancy, and it has an acceptable longterm safety profile.

Autophagy: A new concept in autoimmunity regulation and a novel therapeutic option

Nowadays, pharmacologic treatments of autoinflammatory diseases are largely palliative rather than curative. Most of them result in non-specific immunosuppression, which can be associated with broad disruption of natural and induced immunity with significant and sometimes serious unwanted injuries. Among the novel strategies that are under development, tools that modulate the immune system to restore normal tolerance mechanisms are central. In these approaches, peptide therapeutics constitute a class of agents that display many physicochemical advantages. Within this class of potent drugs, the phosphopeptide P140 is very promising for treating patients with lupus, and likely also patients with other chronic inflammatory diseases. We discovered that P140 targets autophagy, a finely orchestrated catabolic process, involved in the regulation of inflammation and in the biology of immune cells. In vitro, P140 acts directly on a particular form of autophagy called chaperone-mediated autophagy, which seems to be hyperactivated in certain subsets of lymphocytes in lupus and in other autoinflammatory settings. In lupus, the "correcting" effect of P140 on autophagy results in a weaker signaling of autoreactive T cells, leading to a significant improvement of pathophysiological status of treated mice. These findings also demonstrated ex vivo in human cells, open novel avenues of therapeutic intervention in pathological conditions, in which specific and not general targeting is highly pursued in the context of the new action plans for personalized medicines.

Immunosuppression following organ transplantation. Part 1: mechanisms and immunosuppressive agents

Solid organ transplantation has revolutionised medical care by providing a definitive cure for a wide spectrum of end-stage medical conditions. This treatment, however, does not come without complications and poses the risks of rejection, life-threatening infection, malignancies and recurrent organ failure, with significant impacts on patient outcomes. One of the major challenges involved in optimising post-transplant outcomes is managing the immune system's response to the transplanted graft and preventing organ rejection. This is mainly accomplished through the use of immunosuppressant agents, which have become a mainstay of treatment for a majority of post-transplant patients. This article, the first of two parts, discusses the concept of immunosuppression and its importance in the care of patients who have received an organ transplant. It focuses on the pathophysiologic mechanisms involved in transplant rejection and discusses the pharmacologic aspects of immunosuppression and its implications for patient care.

Treatment of antiphospholipid syndrome beyond anticoagulation

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder marked by thrombosis and/or pregnancy morbidity in the presence of antiphospholipid antibodies (aPL). At the present time, treatment is primarily focused on anticoagulation. However, there is increasing awareness of the mechanisms involved in APS pathogenesis, which has led to the trial of novel therapies targeting those mechanisms. Following a brief review of the etiopathogenesis of and current management strategies in APS, this paper focuses on the evidence for these potential, targeted APS treatments, e.g., hydroxychloroquine, statins, rituximab, belimumab, eculizumab, defibrotide, sirolimus, and peptide therapy.

The potential effects of hemp seed/evening primrose oils on the mammalian target of rapamycin complex 1 and interferon-gamma genes expression in experimental autoimmune encephalomyelitis

The mammalian target of rapamycin (mTOR) has a fundamental role in the metabolism, growth, and regulation of the immune system. The interferon gamma (IFN-γ)derived from T helper 1 (Th1) cells is a prominent pro-inflammatory cytokine in multiple sclerosis (MS) and its animal model, the experimental autoimmune encephalomyelitis (EAE). Due to the exclusive role of rapamycin (RAPA) in mTOR complex 1 (mTORC1) inhibition, essentially Th1 differentiation and IFN-γ production, we evaluated the potential therapeutic effects of hemp seed/evening primrose oils (HSO/EPO) in comparison with RAPA administration in EAE. To evaluate the therapeutic effects of EPO/HSO supplement in comparison with RAPA, EAE was induced using myelin oligodendrocyte glycoprotein (MOG) peptide and complete Freund's adjuvant in C57BL/6 mice. The weight, clinical score, and histological findings were evaluated. Total mRNA was extracted from local lymph nodes and qRT-PCR was used for the purpose of the genes expression level of regulatory associated protein of TORC1 (RAPTOR) and IFN-γ. Our results indicated that the relative expression of RAPTOR and IFN-γ genes were significantly reduced in HSO/EPO, RAPA, and RAPA + HSO/EPO treated groups in comparison with the untreated group. Interestingly, histological findings have shown that the HSO/EPO treated group remarkably regenerated the myelin sheath, but this did not occur in the case of RAPA or combined RAPA and HSO/EPO treated groups. Our findings suggeste that HSO/HPO can be used as a potent immunomodulator and as a good candidate for re-myelination and downregulation of immune response for treatment of MS.

Lymphedema of the Transplanted Kidney and Abdominal Wall with Ipsilateral Pleural Effusion Following Kidney Biopsy in a Patient Treated with Sirolimus: A Case Report and Review of the Literature

BACKGROUND Sirolimus is a mammalian target of rapamycin (mTOR) inhibitor, which is used in immunosuppressive treatment regimens in organ transplant recipients. Although mTOR inhibitors are well tolerated, their adverse effects have been reported. Sirolimus treatment in transplant recipients has been reported to be associated with lymphedema of the skin and subcutaneous tissues, and with pleural effusion, but edema of internal organs and organomegaly have not been previously reported. A case is presented lymphedema of the transplanted kidney and abdominal wall with ipsilateral pleural effusion following kidney biopsy in a patient treated with sirolimus. CASE REPORT A 32-year-old woman with a history of end-stage renal disease of unknown etiology had undergone right renal transplantation from an unrelated living donor, eight years previously. She was referred to our hospital with dyspnea, localized abdominal pain, and swelling of the transplanted kidney. The symptoms appeared following a kidney biopsy and the replacement of cyclosporin with sirolimus four months previously. On examination, she had localized swelling of the abdominal wall overlying the transplanted kidney, and a right pleural effusion. Hydronephrosis and nephrotic syndrome were excluded as causes of kidney enlargement. Following the withdrawal of sirolimus therapy her symptoms resolved within three months. CONCLUSIONS A case is described of lymphedema of the transplanted kidney and abdominal wall with ipsilateral pleural effusion following kidney biopsy attributed to her change in anti-rejection therapy to sirolimus. This case report should raise awareness of this unusual complication of sirolimus anti-rejection therapy and its possible effects on the lymphatic system.

mTOR Inhibitors for the Treatment of Severe Congenital Hyperinsulinism: Perspectives on Limited Therapeutic Success

CONTEXT

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycemia in neonates and infants. In medically unresponsive CHI, subtotal pancreatectomy is performed to achieve euglycemia with consequent diabetes in later life. Sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, has been reported to obviate the need for pancreatectomy, but experience is limited.

OBJECTIVE

We have investigated the efficacy and adverse effect profile of mTOR inhibitors in the treatment of severe CHI.

DESIGN, SETTING, AND PATIENTS

This was an observational review of 10 severe CHI patients treated with mTOR inhibitors, in France and the United Kingdom, with the intention of achieving glycemic control without pancreatectomy. Safety information was recorded.

MAIN OUTCOME MEASURE(S)

We examined whether mTOR inhibitors achieved glycemic control, fasting tolerance, and weaning of supportive medical therapy.

RESULTS

mTOR inhibition achieved euglycemia, fasting tolerance, and reduced medical therapy in only three patients (30%). Triglyceride levels were elevated in five patients (50%). One child required a blood transfusion for anemia, four had stomatitis, two had sepsis, one developed varicella zoster, and two patients developed gut dysmotility in association with exocrine pancreatic insufficiency. In silico analysis of transcriptome arrays from CHI patients revealed no significant association between mTOR signaling and disease. Pancreatic tissue from two patients who did not respond to sirolimus showed no reduction in cell proliferation, further suggesting that mTOR signaling did not down-regulate proliferation in the CHI pancreas.

CONCLUSION

mTOR inhibitor treatment is associated with very limited success and must be used with caution in children with severe CHI.

Intravitreal Sirolimus for Noninfectious Uveitis: A Phase III Sirolimus Study Assessing Double-masKed Uveitis TReAtment (SAKURA)

PURPOSE

To evaluate the efficacy and safety of intravitreal sirolimus in the treatment of noninfectious uveitis (NIU) of the posterior segment (i.e., posterior, intermediate, or panuveitis).

DESIGN

Phase III, randomized, double-masked, active-controlled, 6-month study with intravitreal sirolimus.

PARTICIPANTS

Adults with active NIU of the posterior segment (intermediate, posterior, or panuveitis), defined as a vitreous haze (VH) score >1+. Subjects discontinued NIU medications before baseline, except for systemic corticosteroids, which were allowed only for those already receiving them at baseline and were rapidly tapered after baseline per protocol.

METHODS

Intravitreal sirolimus assigned 1:1:1 at doses of 44 (active control), 440, or 880 μg, administered on Days 1, 60, and 120.

MAIN OUTCOME MEASURES

The primary efficacy outcome was the percentage of subjects with VH 0 response at Month 5 (study eye) without use of rescue therapy. Secondary outcomes at Month 5 were VH 0 or 0.5+ response rate, corticosteroid tapering success rate (i.e., tapering to a prednisone-equivalent dosage of ≤5 mg/day), and changes in best-corrected visual acuity (BCVA). Adverse events during the double-masked treatment period are presented.

RESULTS

A total of 347 subjects were randomized. Higher proportions of subjects in the intravitreal sirolimus 440 μg (22.8%; P = 0.025) and 880 μg (16.4%; P = 0.182) groups met the primary end point than in the 44 μg group (10.3%). Likewise, higher proportions of subjects in the 440 μg (52.6%; P = 0.008) and 880 μg (43.1%; P = 0.228) groups achieved a VH score of 0 or 0.5+ than in the 44 μg group (35.0%). Mean BCVA was maintained throughout the study in each dose group, and the majority of subjects receiving corticosteroids at baseline successfully tapered off corticosteroids (44 μg [63.6%], 440 μg [76.9%], and 880 μg [66.7%]). Adverse events in the treatment and active control groups were similar in incidence, and all doses were well tolerated.

CONCLUSIONS

Intravitreal sirolimus 440 μg demonstrated a significant improvement in ocular inflammation with preservation of BCVA in subjects with active NIU of the posterior segment.

67-kDa laminin receptor-dependent protein phosphatase 2A (PP2A) activation elicits melanoma-specific antitumor activity overcoming drug resistance

The Ras/Raf/MEK/ERK pathway has been identified as a major, druggable regulator of melanoma. Mutational activation of BRAF is the most prevalent genetic alteration in human melanoma, resulting in constitutive melanoma hyperproliferation. A selective BRAF inhibitor showed remarkable clinical activity in patients with mutated BRAF. Unfortunately, most patients acquire resistance to the BRAF inhibitor, highlighting the urgent need for new melanoma treatment strategies. Green tea polyphenol (-)-epigallocatechin-3-O-gallate (EGCG) inhibits cell proliferation independently of BRAF inhibitor sensitivity, suggesting that increased understanding of the anti-melanoma activity of EGCG may provide a novel therapeutic target. Here, by performing functional genetic screening, we identified protein phosphatase 2A (PP2A) as a critical factor in the suppression of melanoma cell proliferation. We demonstrated that tumor-overexpressed 67-kDa laminin receptor (67LR) activates PP2A through adenylate cyclase/cAMP pathway eliciting inhibitions of oncoproteins and activation of tumor suppressor Merlin. Activating 67LR/PP2A pathway leading to melanoma-specific mTOR inhibition shows strong synergy with the BRAF inhibitor PLX4720 in the drug-resistant melanoma. Moreover, SET, a potent inhibitor of PP2A, is overexpressed on malignant melanoma. Silencing of SET enhances 67LR/PP2A signaling. Collectively, activation of 67LR/PP2A signaling may thus be a novel rational strategy for melanoma-specific treatment.

Rapamycin promotes Schwann cell migration and nerve growth factor secretion

Rapamycin, similar to FK506, can promote neural regeneration in vitro. We assumed that the mechanisms of action of rapamycin and FK506 in promoting peripheral nerve regeneration were similar. This study compared the effects of different concentrations of rapamycin and FK506 on Schwann cells and investigated effects and mechanisms of rapamycin on improving peripheral nerve regeneration. Results demonstrated that the lowest rapamycin concentration (1.53 nmol/L) more significantly promoted Schwann cell migration than the highest FK506 concentration (100μmol/L). Rapamycin promoted the secretion of nerve growth factors and upregulated growth-associated protein 43 expression in Schwann cells, but did not significantly affect Schwann cell proliferation. Therefore, rapamycin has potential application in peripheral nerve regeneration therapy.

Sirolimus: a switch option for mycophenolate mofetil-induced leukopenia in renal transplant recipients

Mycophenolate mofetil (MMF) is a potent immunosuppressive agent used to prevent acute and chronic rejection in kidney transplantation or for rescue therapy. One side effect of MMF is bone marrow toxicity, including leukopenia, which may necessitate drug withdrawal. We report 2 patients who underwent kidney transplantation and developed leukopenia while receiving MMF and safely switched to sirolimus. A 35-year-old woman underwent deceased donor kidney transplantation. She received basiliximab, tacrolimus, MMF, and a corticosteroid. On postoperative day (POD) 75, her white blood cell (WBC) count was 1800/μL. A 44-year-old women underwent deceased donor kidney transplantation and received basiliximab, tacrolimus, MMF, valganciclovir, and a corticosteroid. On POD 88, her WBC count was 1320/μL. MMF was switched to sirolimus, resulting in recovery of WBC count without rejection. Switch from MMF to sirolimus is safe and favorable in MMF-induced leukopenia in renal transplant recipient.

Serum and renal tissue markers of nephropathy in rats under immunosuppressive therapy: cyclosporine versus sirolimus

Cyclosporin (CsA) has been progressively replaced by other drugs with putatively fever side effects, including nephrotoxicity and hypertension. Sirolimus (SRL) is one of the main options for management of kidney transplant patients in the post-CsA era. It shows identical efficacy with apparently less cardiorenal side effects than CsA. However, doubts remain concerning the mechanisms of putative renoprotection by SRL as well as the best serum and/or tissue markers for nephropathy, as assessed in this study employing CsA- and SRL-treated rats. Three groups (n = 6) were treated orally during a 6-week protocol: control (vehicle); CsA (5 mg/kg body weight per day Sandimmun Neoral); SRL (1 mg/kg body weight per day Rapamune). Blood pressure and heart rate were assessed with a "tail cuff". Renal dysfunction and morphology were characterized using serum creatinine and blood urea nitrogen (BUN) levels as well as hematoxylin and eosin and periodic acid Schiff staining, respectively. We examined serum concentrations of interleukin (IL)-2, IL-1β, high-sensitivity C-reactive protein, tumor necrosis factor TNF-α, and vascular endothelial growth factor and kidney mRNA expression of interleukin-1β (IL-1β), tumor protein 53 (TP53), mammalian target of rapamycin (mTOR) and proliferating cell nuclear antigen (PCNA), as well as markers of lipid peroxidation in the kidney and serum. Both CsA and SRL induced significant increases in systolic and diastolic blood pressure, but only CsA caused tachycardia. CsA-treated rats also displayed increased serum creatinine and BUN levels, accompanied by mild renal lesions, which were almost absent among SRL-treated rats, which presented hyperlipidemic and hyperglycemic profiles. CsA-induced nephrotoxicity was accompanied by kidney overexpression of inflammatory and proliferative mRNA markers (IL-1β, mTOR and PCNA), which were absent among SRL group. In conclusion, the antiproliferative and antifibrotic character of SRL may explain its less nephrotoxic profile. Renal over expression of mTOR in the CsA-treated group, associated with renal dysfunction and structural damage, reinforces the potential beneft of SRL as a strategy to reduce CsA-evoked nephrotoxicity.

p70S6 kinase phosphorylation for pharmacodynamic monitoring

Inhibitors of the mammalian target of rapamycin (mTOR) are administered as immunosuppressant as well as antineoplastic agents. Because of the narrow therapeutic index of mTOR inhibitors, drug monitoring is required, and this is usually done by measuring blood drug levels. Increasing knowledge of the signaling pathways of the mTOR protein kinase provides an opportunity for pharmacodynamic drug monitoring. With the different laboratory methods it is becoming possible to measure new biomarkers to control the influence of mTOR activity. One of these biomarkers is phospho-S6 kinase, with its isoform p70S6K.

Sirolimus in pediatric renal transplantation

SRL, an mTOR inhibitor that inhibits cell cycle progression, represents an important alternative to CNIs, which are still the cornerstones of pediatric solid organ tx. Because there are still limited data on SRL use among pediatric solid organ recipients, further studies are needed to verify the efficacy and safety of SRL. It has unique pharmacokinetic characteristics concerning dosing intervals and reduction of the dose in combination with other immunosuppressants. SRL also has antineoplastic, antiviral, and antiatherogenic advantages over other immunosuppressive agents. The adverse effects of SRL including thrombocytopenia, hyperlipidemia, proteinuria, impaired wound healing, mouth ulcers, edema, male hypogonadism, TMA, and interstitial pneumonitis must be considered carefully in pediatric population. This article reviews the most recent data on SRL application in the field of pediatric renal tx.

Steroid or tacrolimus withdrawal in renal transplant recipients using sirolimus

BACKGROUND

Calcineurin inhibitor (CNI) and steroid (ST) withdrawal are strategies under investigation to reduce long-term toxicities associated with current immunosuppressive regimens. We conducted a single center, prospective trial comparing the efficacy and safety of CNI or ST withdrawal in kidney transplant recipients receiving sirolimus-based immunosuppressive regimen.

METHODS

Forty-seven recipients of first renal transplant with non-HLA-identical living donors received sirolimus (SRL), tacrolimus (TAC), and ST without induction therapy and were randomized to undergo ST (TAC/SRL group, n = 24) or TAC (SRL/ST group, n = 21) withdrawal 3 months after transplantation. Primary efficacy and safety endpoints were the incidence of biopsy-confirmed acute rejection (BCAR) and renal function at 12 months.

RESULTS

No differences were observed in the incidence of BCAR (4.2% vs. 9.5%), graft (95.8% vs. 95.6%), and patient (95.8% vs. 95.6%) survivals or in renal function (60 ± 11.5 vs. 63.4 ± 10.5 ml/min, P = 0.361). Higher mean cholesterol concentration was observed in the SRL/ST group (191.9 ± 63.3 vs. 241.6 ± 61.5 mg/dl, P = 0.019). Treatment discontinuation due to adverse events occurred in 12.5% of patients in TAC/SRL group and 21.7% in SRL/ST group.

CONCLUSION

Within this short period of observation, our study was unable to detect any significant difference in major transplant outcomes comparing CNI and ST elimination strategies.

Identification and elimination of ion suppression in the quantitative analysis of sirolimus in human blood by LC/ESI-MS/MS

Ion suppression can negatively affect the performance characteristics of LC/ESI-MS/MS based methods, and we wished to identify sources of ion suppression in an assay for quantitating sirolimus in human whole blood. We first compared the peak areas of sirolimus and ascomycin added to human blood samples treated with and without extraction using octadecyl silyl (ODS)-silica gel after protein precipitation, and we found that water-soluble compounds cause the ion suppression for both drugs. Post-column infusion studies indicated that compounds retained in the sample after ODS extraction and protein precipitation caused ion suppression. MS analysis of these compounds suggested they were hydroxyl group-possessing phosphocholines, and this was confirmed using purified lysophosphatidylcholine variants. Therefore, we included a HybridSPE treatment step after the ODS extraction into the preanalytical workflow to remove phosphocholines, and this successfully eliminated the observed ion suppression for determining sirolimus concentration in human whole blood by LC/ESI-MS/MS. Sirolimus is a highly lipophilic molecule, and this study demonstrates the impact that preanalytical extraction and purification steps can have on a laboratory's ability to accurately detect and quantitate this and other lipophilic drugs.

New and emerging treatment approaches to lupus

The main goal in systemic lupus erythematosus (SLE) is to achieve remission, as this has a major impact on patient and renal survival. Furthermore, early treatment success has been shown to improve long-term prognosis. Treatment in severe SLE, especially in lupus nephritis, has traditionally been a standardized schematic therapy with cyclophosphamide and prednisolone followed by azathioprine. However, animal and human studies have increased our pathogenetic knowledge of this autoimmune disease with emerging new treatment targets. New and future therapeutic approaches are focused on B-cell depletion, T-cell downregulation and co-stimulatory blockade, cytokine inhibition, or the modulation of complement. Many different biological agents have been used in recent and ongoing studies, but up to now breakthroughs emerging from randomized Phase III trials have been rare. However, the future remains exciting with progress towards safe treatments with which to control the disease in the long run.

Conversion to sirolimus for chronic allograft nephropathy and calcineurin inhibitor toxicity and the adverse effects of sirolimus after conversion

BACKGROUND

Chronic allograft nephropathy and calcineurin inhibitor toxicity may cause graft loss. After kidney transplantation, especially among those patients with chronic allograft nephropathy, sirolimus may be a good alternative to calcineurin inhibitors. Unlike calcineurin inhibitors, sirolimus is devoid of significant nephrotoxicity, but approximately 30% to 50% of patients on sirolimus therapy display mild or severe adverse effects. We sought to report our experience with sirolimus conversion among patients with chronic allograft nephropathy as well as the mild versus severe adverse effects that limit the drug's use.

MATERIALS AND METHODS

We analyzed the outcomes of 88 patients (64 men and 24 women) of overall mean age of 35.9 +/- 9.9 years (range, 21-59 years) who had undergone kidney transplantation. Immunosuppressive therapy had been converted from a calcineurin inhibitor to sirolimus because of biopsy-proven chronic allograft nephropathy, calcineurin inhibitor toxicity, or presence of malignancy. We excluded patients with prior acute rejection episodes. Subjects were divided into two groups with respect to their creatinine levels: Group A < 2 mg/dL and Group B >or= 2 mg/dL. After conversion to sirolimus, possible adverse effects of sirolimus were evaluated at the follow-up inset. Each patient underwent a physical examination, and estimation of serum lipid and electrolyte levels as well as hemoglobin concentration.

RESULTS

At the time of conversion of the 88 renal transplant patients, their mean duration after grafting was 48 +/- 15 months (range, 4-296). The prior treatment consisted of a calcineurin inhibitor, prednisolone, and mycophenolate mofetil. After conversion, the calcineurin inhibitor was stopped and sirolimus was begun. The 48 Group 2 patients (34 men, 14 women) of overall mean posttransplant time of 22.7 +/- 14.6 months who underwent conversion displayed a mean serum creatinine increase to 3.2 +/- 1.4 mg/dL, including 17 subjects who underwent rejection. The 40 Group 1 patients (30 men, 10 women) with a mean overall posttransplant period of 67.6 +/- 49.9 months showed an fall in serum creatinine level to 1.4 +/- 0.5 mg/dL among only 3 patients. While 5/88 patients showed no increase in proteinuria (5.6%); 83 (94.4%) did experience it. Proteinuria increased from a mean of 192 +/- 316 to 449 +/- 422 mg/d. Only three patients displayed heavy proteinuria (>3 g/d); sirolimus was discontinued for this reason. Proteinuria was well controlled in the other patients with angiotensin-converting enzyme and/or angiotensin II receptor inhibitor agents. After sirolimus conversion, serum cholesterol levels increased from 187 +/- 42 to 214 +/- 52 mg/dL, and serum triglyceride levels increased from 161 +/- 61 to 194 +/- 102 mg/dL. All but four patients responded to statin therapy, with serum lipid levels falling to acceptable levels. Another four patients developed unilateral lower extremity edema with sirolimus discontinued for this reason. One patient displayed generalized arthralgia.

CONCLUSION

Chronic allograft nephropathy or calcineurin inhibitor toxicity can lead to loss of graft kidney function. Calcineurin inhibitor toxicity can lead to chronic allograft nephropathy. Patients with a low baseline serum creatinine level who undergo sirolimus conversion showed stabilized kidney function. Late conversion of patients with a serum creatinine above 2 mg/dL face a risk of graft failure. Sirolimus displayed a limited incidence of serious adverse effects; mild or moderate adverse effects, such as hyperlipidemia and proteinuria, were easily controlled with countermeasure therapy.

VEGF inhibitors for the treatment of neovascular age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness in the Western world for those patients aged 50 years or older. Neovascular AMD, a subtype characterized by the growth of new, pathologic blood vessels, results in most of the cases of severe and rapid vision loss associated with AMD. A critical activator of angiogenesis in neovascular AMD is VEGF. Several therapies have been and are now being developed for neovascular AMD, with the goal of inhibiting VEGF. These VEGF inhibitors include the RNA aptamer pegaptanib, partial and full-length antibodies ranibizumab and bevacizumab, VEGF receptor decoy VEGF Trap, small interfering RNA-based therapies bevasiranib and AGN211745, sirolimus, and tyrosine kinase inhibitors including vatalanib, pazopanib, TG100801, TG101095, AG013958 and AL39324. At present, established therapies have met with great success in reducing the vision loss associated with neovascular AMD, whereas those still investigational in nature offer the potential for further advances.

Limited sampling strategies for sirolimus after pediatric renal transplantation

SRL has been increasingly used in renal transplantation, but limited sampling approaches for estimation of AUC remain elusive. A post-hoc analysis of 94 PK profiles in 75 patients from four previous studies was performed to generate limited sampling approaches for approximation of AUC based on two to four time points for both BID and OD SRL dosing. AUC was calculated using the trapezoid rule. Stepwise linear regression was performed to generate an abbreviated AUC from the limited sampling approaches. For BID dosing, complete AUC had a strong correlation with the trough levels (r(2) = 0.882, p < 0.0001) and with C2 level (r(2) = 0.9025, p < 0.0001). A three-point and a four-point limited sampling approach showed improved agreement with complete AUC compared with single-point sampling. A convenient and accurate (r(2) = 0.992) four-point limited sampling approach reads: AUC = 10;(1.085 + 0.117 x log C0 + 0.164 x log C1-0.131 x log C2 + 0.823 x log C4). Similarly, complete AUC had a statistically significant correlation with the trough levels (r(2) = 0.549, p < 0.0001) and with C2 level (r(2) = 0.716, p < 0.0001) for OD dosing. The estimation of AUC for OD dosing was improved over single-point sampling (r(2) = 0.951) using the formula: AUC = 10;(1.100 + 0.115 x log C0 + 0.803 x log C4). This study represented the first limited sampling approach for SRL. Further studies are required to determine the optimal SRL target AUC.

Gingival status of Brazilian renal transplant recipients under sirolimus-based regimens

BACKGROUND

Although the prevalence of gingival overgrowth (GO) in calcineurin-inhibitor (CNI) immunosuppressive regimens has been well documented, to the best of our knowledge data from sirolimus (SIR) regimens have not been described. We sought to investigate the gingival status of renal transplant recipients under SIR-based regimens with regard to the prevalence and potential risk variables associated with GO.

METHODS

A cross-sectional study was conducted at a public hospital in Belo Horizonte, MG, Brazil. Of 886 transplant recipients, an eligible sample of 144 subjects was selected. Medical, pharmacologic, and periodontal variables were recorded for each subject. GO was assessed through visual inspection and was evaluated in relation to variables of interest by univariate and multivariate analyses.

RESULTS

Although not clinically significant, 20.8% of the samples had GO, with a mean GO score of 5.0% +/- 3.98% (range, 0% to 19%) and mean GO score per papilla of 0.378 +/- 0.361 (range, 0.1 to 1.9); the percentage of papilla affected by GO was 14.35% +/- 9.86% (range, 5% to 45%). The multivariate final model, excluding periodontal variables, showed that the concomitant use of calcium channel blockers (P = 0.033) and the interaction between time since transplant and previous CNI use (P <0.001) were associated with GO. Adding periodontal variables to the model improved its accuracy and retained papillary bleeding index as being strongly associated with GO (P <0.001).

CONCLUSIONS

GO was observed in a considerable number of subjects under SIR-based immunosuppressive regimens, although the relationship was not clinically significant. Findings point to the importance of cooperation between medical and dental health care personnel in the maintenance of renal transplant recipients under SIR-based immunosuppressive regimens.

Chronic allograft nephropathy

PURPOSE OF REVIEW

Despite dramatic declines in acute rejection and early graft failure, long-term outcomes after kidney transplantation have improved little during the past 25 years. Most late allograft failure is attributed to chronic allograft nephropathy, but this is a clinicopathological description and not a diagnosis, and its pathogenesis and treatment are largely unknown.

RECENT FINDINGS

Recent studies suggest that acute rejection during the first few months, and calcineurin inhibitor toxicity thereafter, may both contribute to chronic allograft nephropathy. There is also accumulating evidence that injury from antibody-mediated rejection may play an important pathogenic role in at least some patients with chronic allograft nephropathy, particularly those with transplant glomerulopathy. Therapeutic measures, including protocols to reduce calcineurin inhibitor exposure, remain largely unproven.

SUMMARY

Understanding why so many kidney allografts fail, despite effective preventive measures for early acute rejection, is one of the most important areas of research in kidney transplantation today.

Renal cortex neuronal nitric oxide synthase in response to rapamycin in kidney transplantation

Decreased renal neuronal nitric oxide synthase (nNOS) is present in various chronic kidney diseases although there is relative little known in chronic allograft nephropathy (CAN). Female sex increases the risk of acute rejection and calcineurin-inhibitor toxicity but decreases the risk of CAN. Rapamycin (RAPA) is an alternative immunosuppress although there is no information whether it is effective in females. We therefore investigated the efficacy of RAPA in both sexes and the impact of RAPA on renal cortex structure and nNOS expression. Male (M) and female (F) F344 kidneys were transplanted into same sex Lewis (ALLO) or F344 (ISO) recipients and treated with 1.6 mg/kg/day of RAPA for 10 days. Grafts were removed for renal histology and endothelial (e)NOS and neuronal (n)NOS protein measurements at 22 weeks. All ALLO rats survived without acute rejection. ALLO F survived with mild proteinuria and CAN at 22 weeks similar to ALLO M, while ISO F had better outcome than ISO M. Cortical nNOSalpha was undetectable in all RAPA groups; however, nNOSbeta transcript and protein were compensatory increased. Both ALLO and ISO F showed higher medullary nNOSalpha but lower cortical eNOS abundance than M groups. In male ALLO RAPA decreased renal cortical nNOSalpha but increased nNOSbeta expression. This may represent compensatory upregulation of nNOSbeta when nNOSalpha-derived NO is deficient.

Sirolimus is not always responsible for new-onset proteinuria after conversion for chronic allograft nephropathy

An eight-yr-old combined liver and kidney transplant recipient for hyperoxaluria type I developed significant proteinuria and hypertension after conversion of a Tacrolimus, MMF, and corticosteroids-based immunosuppression to Sirolimus, low-dose Tacrolimus, and corticosteroids six and a half yr after the transplant for chronic allograft nephropathy. There was only one class I HLA match and the recipient had multiple blood exposures prior to transplantation. The patient was treated with combined hemodialysis and peritoneal dialysis while awaiting transplantation to reduce the oxalate load. A renal biopsy revealed a de novo transplant glomerulopathy that was associated with specific HLA antibodies unrelated to the donor (HLA DR 17 and 18). After reintroduction of MMF, these antibodies became undetectable and the proteinuria completely resolved. We hypothesize that HLA antibodies may cause transplant glomerulopathy even if they are not donor-specific. Their production appears more susceptible to MMF therapy. A thorough work-up of new-onset proteinuria after conversion to Sirolimus should be performed, including an immunological work-up and a renal biopsy.