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Nanomedicine holds great potential for revolutionizing medical treatment. Ongoing research and advancements in nanotechnology are continuously expanding the possibilities, promising significant advancements in healthcare. To fully harness the potential of nanotechnology in medical applications, it is crucial to conduct safety evaluations for the nanomedicines that offer effective benefits in the preclinical stage. Our recent efficacy studies indicated that rapamycin perfluorocarbon (PFC) nanoparticles showed promise in mitigating cisplatin-induced acute kidney injury (AKI). As cisplatin is routinely administered to ovarian cancer patients as their first-line chemotherapy, in this study, we focused on evaluating the safety of rapamycin PFC nanoparticles in mice bearing ovarian tumor xenografts. Specifically, this study evaluated the effects of repeat-dose rapamycin PFC nanoparticle treatment on vital organs, the immune system, and tumor growth and assessed pharmacokinetics and biodistribution. Our results indicated that rapamycin PFC nanoparticle treatment did not cause any detectable adverse effects on cardiac, renal, or hepatic functions or on splenocyte populations, but it reduced the splenocyte secretion of IL-10, TNFα, and IL12p70 upon IgM stimulation. The pharmacokinetics and biodistribution results revealed a significant enhancement in the delivery of rapamycin to tumors by rapamycin PFC nanoparticles, which, in turn, led to a significant reduction in ovarian tumor growth. Therefore, rapamycin PFC nanoparticles have the potential to be clinically beneficial in cisplatin-treated ovarian cancer patients. [ABSTRACT FROM AUTHOR]

In our study, we examined the efficacy of mTOR (mammalian target of rapamycin) inhibitors, specifically rapamycin (Rap), compared to calcineurin inhibitors (CNIs) in kidney transplantation. By conducting a comprehensive search across reputable databases (EMBASE, Scopus, PubMed, Cochrane, and Crossref), we gathered data for a six-month post-transplantation period. Our analysis revealed that mTOR inhibitor administration resulted in improved glomerular filtration rate (GFR) and serum creatinine levels. However, it is important to note that the mTOR inhibitor group had a higher incidence of acute rejection after biopsy. Through molecular modeling, we observed that Rap exhibited a superior binding affinity for mTOR compared to CNIs' binding to calcineurin, probably contributing to the transplant rejection. Our meta-analysis supports the cautious use of an optimal mTOR inhibitor in conjunction with careful consideration of clinical features when minimizing CNIs early in the transplantation process. This is because mTOR inhibitors have complementary mechanisms of action, a low nephrotoxicity profile, and favorable outcomes in serum creatinine and GFR, which contribute to improved transplant survival. [ABSTRACT FROM AUTHOR]

Rapamycin is an mTOR inhibitor that has been shown to extend the lifespan of laboratory model organisms. In humans, rapamycin is used at higher doses as an immunosuppressive medication to prevent organ rejection. Numerous adverse effects are seen with rapamycin treatment in humans, with one of the most common being dysregulation of lipid metabolism. In humans, this often manifests as mild to moderate serum lipid elevations, with a small subset developing extreme triglyceride elevations. This case report describes an eight-year-old, castrated male, clinically healthy Labrador retriever who developed severe hypertriglyceridemia associated with low-dose rapamycin administration over a six-month period. During this time, the dog was asymptomatic and displayed no other clinical abnormalities, aside from a progressive lipemia. Within 15  days of discontinuing rapamycin treatment, and with no targeted lipemic intervention, the dog’s lipemia and hypertriglyceridemia completely resolved. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to explore the effect of Rapamycin (Rapa) in Staphylococcus aureus (S. aureus) pneumonia and clarify its possible mechanism.Methods: We investigated the effects of Rapa on S. aureus pneumonia in mouse models and in macrophages cultured in vitro. Two possible mechanisms were investigated: the mTOR-RPS6 pathway phosphorylation and phagocytosis. Furthermore, for the mechanism verification in vivo, mice with specific Mtor knockout in myeloid cells were constructed for pneumonia models.Results: Rapa exacerbated S. aureus pneumonia in mouse models, promoting chemokines secretion and inflammatory cells infiltration in lung. In vitro, Rapa upregulated the secretion of chemokines and cytokines in macrophages induced by S. aureus. Mechanistically, the mTOR-ribosomal protein S6 (RPS6) pathway in macrophages was phosphorylated in response to S. aureus infection, and the inhibition of RPS6 phosphorylation upregulated the inflammation level. However, Rapa did not increase the phagocytic activity. Accordingly, mice with specific Mtor knockout in myeloid cells experienced more severe S. aureus pneumonia.Conclusion: Rapa exacerbates S. aureus pneumonia by increasing the inflammatory levels of macrophages. Inhibition of mTOR-RPS6 pathway upregulates the expression of cytokines and chemokines in macrophages, thus increases inflammatory cells infiltration and exacerbates tissue damage. [ABSTRACT FROM AUTHOR]

Background: Sirolimus is a potent immunosuppressive in renal transplantation. However, its use is limited by some reported side effects. The objective of this study was to determine the side effect profile of sirolimus in renal transplant patients. Materials and Methods: In the present study, we retrospectively reviewed the medical records of 116 renal transplant patients treated with sirolimus alone or in combination with other immunosuppressive agents at private therapeutic centers in Isfahan, Iran, between March 2009 and February 2020. A checklist was used to collect data on demographic and clinical variables. Data were analyzed with independent samples t test and Chi squared test. Results: Our findings indicated that the most prevalent sirolimus related side effects were edema (42.3%), proteinuria (37.5%), cytopenia (26.9%), abnormal level of liver enzymes (11.7%), and pneumonitis (9.7%). Stratification of side effects by sirolimus dose (<2 mg and ≥2 mg) demonstrated their dose independent occurrence (P > 0.05). Pneumonitis was the most frequent reason for sirolimus cessation (58.7%). No significant differences were observed between males and females regarding the frequency of reasons for sirolimus cessation (P > 0.05). Conclusion: Edema, proteinuria, cytopenia, abnormal level of liver enzymes, and pneumonitis were the most prevalent sirolimus related side effects in renal transplant patients. Further prospective cohort studies are warranted to detect underlying mechanisms and determinants of these side effects in renal transplant patients treated with sirolimus. [ABSTRACT FROM AUTHOR]

The advancement in pharmaceutical research has led to the discovery and development of new combinatorial life-saving drugs. Rapamycin is a macrolide compound produced from Streptomyces hygroscopicus. Rapamycin and its derivatives are one of the promising sources of drug with broad spectrum applications in the medical field. In recent times, rapamycin has gained significant attention as of its activity against cytokine storm in COVID-19 patients. Rapamycin and its derivatives have more potency when compared to other prevailing drugs. Initially, it has been used exclusively as an anti-fungal drug. Currently rapamycin has been widely used as an immunosuppressant. Rapamycin is a multifaceted drug; it has anti-cancer, anti-viral and anti-aging potentials. Rapamycin has its specific action on mTOR signaling pathway. mTOR has been identified as a key regulator of different pathways. There will be an increased demand for rapamycin, because it has lesser adverse effects when compared to steroids. Currently researchers are focused on the production of effective rapamycin derivatives to combat the growing demand of this wonder drug. The main focus of the current review is to explore the origin, development, molecular mechanistic action, and the current therapeutic aspects of rapamycin. Also, this review article revealed the potential of rapamycin and the progress of rapamycin research. This helps in understanding the exact potency of the drug and could facilitate further studies that could fill in the existing knowledge gaps. The study also gathers significant data pertaining to the gene clusters and biosynthetic pathways involved in the synthesis and production of this multi-faceted drug. In addition, an insight into the mechanism of action of the drug and important derivatives of rapamycin has been expounded. The fillings of the current review, aids in understanding the underlying molecular mechanism, strain improvement, optimization and production of rapamycin derivatives. [ABSTRACT FROM AUTHOR]

Background: While autophagy is essential for stem cells' self-renewal and differentiation, its effect on bone marrow mesenchymal stem cells (BMSCs) remains unclear. This study aimed to investigate the interaction between autophagy and osteogenic differentiation using rapamycin (RAPA), a classical autophagy agonist with osteo-regulatory effects. Methods: Rat BMSC's autophagy was analyzed after osteoinduction (0, 7, 14, and 21 d) by western blotting, immunofluorescence, and real-time quantitative polymerase chain reaction (RT-qPCR). In addition, we evaluated osteogenic differentiation using alizarin red staining, alkaline phosphatase assays, and RT-qPCR/Western blotting quantification of bone sialoprotein, type 1 collagen, alkaline phosphatase, osteopontin, and Runt-related transcription factor 2 mRNA and protein levels. Results: The BMSC's basal autophagy level gradually decreased during osteogenic differentiation with a decrease in BECN1 level and the lipidated (LC3-II) to unlipidated (LC3-I) microtubule-associated protein 1 light chain 3 ratio and an increase in the expression of selective autophagic target p62. In contrast, it increased with increasing RAPA concentration. Furthermore, while 2 nM RAPA promoted BMSC osteogenic differentiation on days 7 and 14, 5 nM RAPA inhibited osteogenesis on days 14 and 21. Inhibition of autophagy by the inhibitor 3-methyladenine could impair RAPA's osteogenesis-enhancing effect on BMSCs. Conclusions: The BMSC's basal autophagy level decreased over time during osteogenic differentiation. However, an appropriate RAPA concentration promoted BMSC osteogenic differentiation via autophagy activation. [ABSTRACT FROM AUTHOR]

Long‐term survival of transplant recipients is significantly impacted by malignancy. We aimed to determine whether calcineurin inhibitor (CNI)‐treated recipients converted to and weaned off molecular target of rapamycin inhibitor (mTOR‐I) therapy have favorable changes in their molecular profiles in regard to malignancy risk. We performed gene expression profiling from liver biopsy and blood (PBMC) specimens followed by network analysis of key dysregulated genes, associated diseases and disorders, molecular and cellular functions using IPA software. Twenty non‐immune, non‐viremic patients were included, and 8 of them achieved tolerance. Two comparisons were performed: (1) tolerance time point vs tacrolimus monotherapy and (2) tolerance time point vs sirolimus monotherapy. Upon achieving tolerance, IPA predicted significant activation of DNA damage response (p = 5.40e‐04) and inhibition of DNA replication (p = 7.56e‐03). Conversion from sirolimus to tolerance showed decrease in HCC (p = 1.30e‐02), hepatic steatosis (p = 5.60e‐02) and liver fibrosis (p = 2.91e‐02) associated genes. In conclusion, this longitudinal study of patients eventually achieving tolerance reveals an evolving molecular profile associated with decreased cancer risk and improved hepatic steatosis and liver fibrosis. This provides a biological rationale for attempting conversion to mTOR‐I therapy and tolerance following liver transplantation particularly in patients at higher risk of cancer incidence and progression post‐transplant. [ABSTRACT FROM AUTHOR]

Background: To determine the safety and efficacy of intravitreal sirolimus and adjunct aflibercept in subjects with persistent, exudative age-related macular degeneration despite previous intravitreal anti-vascular endothelial growth factor (VEGF) treatment. Methods: This institutional review board approved, registered (NCT02732899), prospective, subject-masked, single center, randomized controlled trial in subjects with persistent, exudative age-related macular degeneration compared alternating monthly intravitreal sirolimus and aflibercept (combination) versus aflibercept monotherapy (control) every 2 months over the course of 36 weeks. The primary measure of efficacy in the study was the mean change in central subfield thickness. Results: 20 subjects were enrolled in the study, with 10 subjects assigned to each treatment group. Subjects had an average of 38 previous anti-VEGF injections. Mean central subfield thickness decreased in the combination group by 54.0 μm compared to 0.1 μm in the control group (p = 0.28). Mean visual acuity improved in the combination group by 2.5 ETDRS letters versus 0.8 ETDRS letters in the control group (p = 0.42). There were no serious ocular adverse events in either group; however, there were three serious systemic events in the combination group, including hospitalizations due to pancreatitis, pneumonia, and worsening hypertension. Conclusion: There was no statistically significant difference in the mean central subfield thickness change between the combination and control groups. However, intravitreal sirolimus with adjunct aflibercept did appear to have potential anatomical benefits as a treatment for persistent, exudative age-related macular degeneration and requires further investigation with a larger cohort to better understand the potential risks and benefits. Trial registration: ClinicalTrials.gov, NCT02732899. Registered 11 March 2016, https://clinicaltrials.gov/ct2/show/NCT02732899. This trial was approved by the institutional review board at Advarra. Funding was provided by an investigator-initiated grant from Santen. Santen played no role in the design or implementation of this study. [ABSTRACT FROM AUTHOR]

Sirolimus and everolimus are mammalian target of rapamycin inhibitors (mTORi) that can reduce relapse rates following liver transplantation (LT) for hepatocellular carcinoma (HCC). Herein, we performed a systematic review and meta‐analysis to investigate the efficacy of mTORi and calcineurin inhibitors (CNI) in reducing HCC recurrence and survival adverse effects (AEs) in HCC patients after LT. Systematic literature searches were conducted using MEDLINE, EMBASE, and Cochrane Library databases up to October 2021. The primary outcomes of interest were tumor recurrence rates and overall survival. The secondary outcomes were the characterization and incidence of AEs. A total of 38 trials involving 10,607 participants was included in the analysis. The incidence of recurrence and overall mortality was significantly lower in the mTORi than in the CNI group (relative ratio [RR]:.78, 95% confidence interval [CI]:.68‒.89 and RR:.76, 95% CI:.67‒.86, respectively). The incidence of some AEs and complications such as acne, anemia, abnormal healing, dyslipidemia, depression, diarrhea, edema, headache/migraine, hypercholesterolemia, incisional hernia, infection, leukopenia, mouth ulceration, pyrexia, proteinuria, pruritis, rash, and thrombocytopenia were higher in the mTORi than in the CNI group. mTORi reduced the recurrence incidence and overall 5‐year mortality rate but increased many other incidences of AEs compared with that by CNI. Therefore, clinicians should be aware of the risks and benefits of mTORi use when managing patients undergoing LT for HCC. [ABSTRACT FROM AUTHOR]

Background. Recent genetic studies indicated that variants of autophagy genes were associated with the predisposition of Crohn's disease (CD). The autophagy deficiency may affect the innate and adaptive immunity, which is related to persistent and excessive inflammation of the bowel. However, it remains unclear how autophagy modulates the expression of immune response regulator NF-κB and proinflammatory cytokine TNF-α in CD. Aim. We aimed to investigate the role of rapamycin on the expression of NF-κB p65 and TNF-α in 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced mouse colitis and lipopolysaccharide (LPS)-induced HT-29 cells. Methods. TNBS-induced colitis mice were treated with saline or rapamycin, and the disease activity index (DAI) and histological scores of colonic mucosa were evaluated. The expressions of p65, ATG16L1 and LC3 were detected by western blot and immunohistochemistry staining. The monodansylcadaverine (MDC) staining and transmission electron microscopy were developed to study the autophagy in LPS-induced HT-29 cells. Expression of TNF-α from colon tissue and HT-29 cells were detected by ELISA. The expressions of p65, ATG16L1 and LC3 in active CD patients were also investigated. Results. Significantly more autophagosomes were observed in rapamycin-treated cells than in controls. Rapamycin remarkably upregulated the expression of ATG16L1 and LC3II, inhibited p65 nucleus translocation and secretion of TNF-α both in vivo and in vitro. The expression of both ATG16L1 and LC3II increased in mild to moderate CD specimens, while no significant difference was noted between severe CD and normal controls. The expression of p65 increased notably in severe CD compared to those in mild to moderate patients. Conclusions. In LPS-treated HT-29 cells and TNBS-induced colitis, p65 is overexpressed, which results in exaggerated secretion of TNF-α and induce or worsen the inflammation in the bowel. Rapamycin protects against colitis through induction of autophagy, thus inhibiting the activation of NF-κB pathway and secretion of TNF-α. [ABSTRACT FROM AUTHOR]

(1) Background: Following renal transplantation, infection with cytomegalovirus (CMV) is a common and feared complication. mTOR-inhibitor (mTOR-I) treatment, either alone or in combination with calcineurininhibitors (CNIs), significantly reduces the CMV incidence after organ transplantation. As of now, there is no information on which mTOR-I, sirolimus (SIR) or everolimus (ERL), has a stronger anti-CMV effect. (2) Methods: The current literature was searched for prospective randomized controlled trials in renal transplantation. There were 1164 trials screened, of which 27 could be included (11,655 pts.). We performed a network meta-analysis to analyze the relative risk of different types of mTOR-I treatment on CMV infection 12 months after transplantation compared to CNI treatment. (3) Results: Four different types of mTOR-I treatment were analyzed in network meta-analyses—SIR mono, ERL mono, SIR with CNI, ERL with CNI. The mTOR-I treatment with the strongest anti-CMV effect compared to a regular CNI treatment was ERL in combination with a CNI (relative risk (RR) 0.27, confidence interval (CI) 0.22–0.32, p < 0.0001). The other mTOR-I therapy groups showed a slightly decreased anti-CMV efficacy (SIR monotherapy (mono): RR 0.35, CI 0.22–0.57, p < 0.001; SIR with CNI: RR 0.43, CI 0.29–0.64, p < 0.0001; ERL mono: RR 0.46, CI 0.22–0.93, p = 0.031). (4) Conclusions: The anti-CMV effect of both mTOR-Is (SRL and ERL) is highly effective, irrespective of the combination with other immunosuppressive drugs. Certain differences with respect to the potency against the CMV could be found between SRL and ERL. Data gained from this analysis seem to support that a combination of ERL and CNI has the most potent anti-CMV efficacy. [ABSTRACT FROM AUTHOR]

Rapamycin is an immunosuppressant used for treating many types of diseases such as kidney carcinomas. In yeast, rapamycin inhibits the TORC1 kinase signaling pathway causing rapid alteration in gene expression and ultimately cell cycle arrest in G1 through mechanisms that are not fully understood. Herein, we screened a histone mutant collection and report that one of the mutants, H2B R95A, is strikingly resistant to rapamycin due to a defective cell cycle arrest. We show that the H2B R95A causes defects in the expression of a subset of genes of the pheromone pathway required for α factor-induced G1 arrest. The expression of the STE5 gene and its encoded scaffold protein Ste5, required for the sequential activation of the MAPKs of the pheromone pathway, is greatly reduced in the H2B R95A mutant. Similar to the H2B R95A mutant, cells devoid of Ste5 are also resistant to rapamycin. Rapamycin-induced G1 arrest does not involve detectable phosphorylation of the MAPKs, Kss1, and Fus3, as reported for α factor-induced G1 arrest. However, we observed a sharp induction of the G1 cyclin Cln2 (~ 3- to 4-fold) in the ste5Δ mutant within 30 min of exposure to rapamycin. Our data provide a new insight whereby rapamycin signaling via the Torc1 kinase may exploit the pheromone pathway to arrest cells in the G1 phase. [ABSTRACT FROM AUTHOR]

Mammalian target of rapamycin inhibitors (mTOR-I) lacks nephrotoxicity, has antineoplastic effects, and reduces viral infections in kidney transplant recipients. Earlier studies reported a significant incidence of wound healing complications and lymphocele. This resulted in the uncomfortable willingness of transplant clinicians to use these agents in the immediate posttransplant period. As evidence and experience evolved over time, much useful information became available about the optimal use of these agents. Understandably, mTOR-I effects wound healing through their antiproliferative properties. However, there are a lot of other immunological and nonimmunological factors which can also contribute to wound healing complications. These risk factors include obesity, uremia, increasing age, diabetes, smoking, alcoholism, and protein-energy malnutrition. Except for age, the rest of all these risk factors are modifiable. At the same time, mycophenolic acid derivatives, steroids, and antithymocyte globulin (ATG) have also been implicated in wound healing complications. A lot has been learnt about the optimal dose of mTOR-I and their trough levels, its combinations with other immunosuppressive medications, and patients' profile, enabling clinicians to use these agents appropriately for maximum benefits. Recent randomized control trials have further increased the confidence of clinicians to use these agents in immediate posttransplant periods. [ABSTRACT FROM AUTHOR]

Summary: Background: Vascular malformations are a complex pathology with few treatment options. In previously published studies, oral sirolimus (rapamycin) has shown promising results in the treatment of low‐flow vascular malformations, but its usefulness in high‐flow vascular malformations is controversial. Aim: To evaluate the efficacy and safety of sirolimus for the treatment of high‐flow vascular malformations in real‐life practice. Methods: In a unit specializing in vascular anomalies, patients treated with oral sirolimus for high‐flow vascular malformations were located by consulting the drug dispensations. Reviewing the electronic medical records, data on patient demographics, vascular malformation characteristics, treatments, toxicity and clinical course were collected and statistically analysed. Results: Nine patients with vascular malformations were included: eight had arteriovenous malformation and one had arteriovenous fistula. Six of these malformations were isolated while three were part of a syndrome. Sirolimus was initiated at a dosage of 1–4 mg/day to be taken as a single dose. Partial response was observed in eight of the nine patients (88.9%) with high‐flow vascular malformation, while worsening was observed in the remaining patient. The treatment was well tolerated and at the most recent follow‐up, five patients remained on treatment with oral sirolimus. Conclusion: Our results show that oral sirolimus is a well‐tolerated therapeutic option, with an excellent safety profile, which can be useful in the long‐term stabilization of patients with high‐flow vascular malformations. Single‐daily dosage may improve long‐term adherence to treatment without worsening its effectiveness. [ABSTRACT FROM AUTHOR]

Background: One of the important causes of mortality and morbidity in kidney transplanted patients is Post Transplant Lymphoproliferative Disease (PTLD), which is due to immunosuppression therapy and viral activity. It seems that Rapamycin, with dual antineoplastic and immunosuppressive effects, may have a pivotal role in the treatment of PTLD patients and preserving transplanted kidneys. Methods and Materials: Twenty patients with PTLD were enrolled. Immunosuppressive therapy was reduced or ceased, and Rapamycin was initiated at the time of PTLD diagnosis. We evaluated the effects of switching immunosuppressive drugs to Rapamycin on graft status, the response of tumor, and 6, 12 months, and 5-year survival in patients. Results: PTLD remission was achieved in 14 patients, while six patients died; no relapse was detected in recovered patients. The median of PTLD free time was 25 months, and the mean overall survival in patients with PTLD treated by Rapamycin was 84.8 (95% CI=61.3-108.23).The five-year survival rate was 67%, 12 months survival was 73.8%, and six months' survival was 80%. The response rate to Rapamycin and immunosuppression reduction alone was 46.6%. Four out of 13 Diffuse Large B-Cell Lymphoma patients achieved a complete response just only after the reduction of immunosuppressive drugs and the consumption of Rapamycin. Conclusion: The present study demonstrated the effectiveness of conversion from immunosuppressive medication, particularly of Calcineurin inhibitors to Rapamycin in PTLD patients. However, more research is needed to confirm the Rapamycin effect on patients with PTLD. [ABSTRACT FROM AUTHOR]

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Summary: To review our experience using sirolimus in a single centre paediatric intestinal transplantation cohort. Intestinal transplant patients with more than 3 months follow‐up were divided into two groups according to their immunosuppression regimen: tacrolimus, (TAC group, n = 45 grafts) or sirolimus (SRL group, n = 38 grafts), which included those partially or completely converted from tacrolimus to sirolimus. The indications to switch were tacrolimus side effects and immunological complications. Survival and complications were retrospectively analysed comparing both groups. SRL was introduced 9 months (0 months–16.9 years) after transplant. The main cause for conversion was worsening renal function (45%), followed by haemolytic anaemia (21%) and graft‐versus‐host‐disease (16%). Both groups showed a similar overall patient/graft survival (P = 0.76/0.08) and occurrence of rejection (24%/17%, P = 0.36). Immunological complications did not recur after conversion. Renal function significantly improved in most SRL patients. After a median follow‐up of 65.17 months, 28/46 survivors were on SRL, 26 with monotherapy, with good graft function. Over one‐third of our patients eventually required SRL conversion that allowed to improve their kidney function and immunological events, without entailing additional complications or survival impairment. Further trials are warranted to clarify the potential improvement of the standard tacrolimus maintenance by sirolimus conversion or addition. [ABSTRACT FROM AUTHOR]

Background: A systematic review and meta-analysis were performed to investigate the efficacy and safety of conversion from calcineurin inhibitors (CNIs) to mammalian target of rapamycin inhibitors (mTORi) in kidney transplant recipients (KTRs). Methods: MEDLINE, EMBASE, PubMed, and Cochrane Library were searched to identify randomized controlled trials (RCTs) that compared the continuation of CNI with conversion to mTORi therapy. Results: Twenty-nine RCTs (5,747 KTRs) were included in our analysis. Meta-analysis of the glomerular filtration rate (SMD 0.20; 95%CI 0.10–0.31; P<0.01) and malignancy (RR 0.74; 95%CI 0.55–0.99; P=0.04) demonstrated a significant advantage of mTORi conversion over CNI continuation. However, the risk of acute rejection (RR 1.58; 95%CI 1.22–2.04; P<0.01), infection (RR 1.55; 95%CI 1.01–1.31; P=0.04), proteinuria (RR 1.87; 95%CI 1.34–2.59; P<0.01), leukopenia (RR 1.56; 95%CI 1.27–1.91; P<0.01), acne (RR 6.43; 95%CI 3.43–12.04; P<0.01), and mouth ulcer (RR 11.70; 95%CI 6.18–22.17; P<0.01) were higher in the mTORi group. More patients in the conversion group had to discontinue study medication (RR 2.52; 95%CI 1.75–3.63; P<0.01). There was no significant difference between the two groups with regard to death, graft loss, diabetes, chronic allograft nephropathy, and interstitial fibrosis/tubular atrophy. Conclusions: Posttransplant patients have a better graft function and lower incidence of malignancy after conversion from CNI to mTORi therapy. However, this conversion strategy may be prevented by the higher drug discontinuation rate due to mTORi-associated adverse events, such as more acute rejection, infection, proteinuria, leukopenia, acne, and mouth ulcer, indicating that conversion therapy may only be a treatment option in selected patients. [ABSTRACT FROM AUTHOR]

Background Renal transplant recipients have an increased cancer risk. The mammalian target of rapamycin inhibitor sirolimus (SRL) has immunosuppressive and antitumour activities but knowledge about its use in recipients with cancer is limited. Methods We retrospectively analysed 726 renal allograft recipients converted to SRL from 10 German transplant centres. Patient and graft survival were analysed depending on malignancy status prior to conversion and tumour entity. Results Malignancy before conversion to SRL was reported in 230 patients, with 137 patients having skin cancers and 101 having solid cancers. Cancer occurred 4.6 ± 9.4 (median 3.0) years after transplantation. Basal cell carcinoma, squamous cell carcinoma and Bowen's disease were the most prevalent skin cancers, while carcinomas of the kidney, colon and breast were the most prevalent solid cancers before conversion. Patients with prior malignancy were older and had better renal function at conversion compared with patients without a history of cancer. After conversion to SRL, cancer incidence rates (IRs) of all tumours were lower compared with rates before conversion. Cancer IRs after conversion were higher in patients with malignancy before conversion compared with those without. Patient survival was worse in patients with solid cancers compared with patients with skin cancers or without malignancies. Biopsy-proven acute rejections in the first year after conversion were less frequent in patients with malignancy compared with those without. Graft survival and renal function in all cancer types were better than in patients converted to SRL without cancers. Conclusions Conversion to SRL in patients with a history of cancer is safe regarding renal function and graft survival, while patient survival is largely dependent on tumour entity. [ABSTRACT FROM AUTHOR]

Background: Port Wine Stain (PWS) is a congenital capillary malformation. Although multiple treatments are required, the gold standard treatment for PWS is Pulsed Dye Laser (PDL). Given its anti‐angiogenic effects, sirolimus can be considered as an adjuvant to PDL in PWS. Aim: To evaluate the efficacy and safety of topical sirolimus (Rapamycin) 0.2% cream as adjuvant therapy for PDL for PWS. Methods: In this randomized double‐blind placebo‐controlled trial, 15 patients with PWS were enrolled. Each lesion was divided into upper and lower parts, and each part was assigned randomly to receive PDL (4 sessions, 2 months apart) plus sirolimus vs PDL and placebo. The response was evaluated using colorimetry, investigator global assessment (IGA), and patient global assessment (PGA) every two months for eight continuous months. Results: According to the colorimetric analysis, medial and lateral sides of the treatment and placebo parts did not differ significantly (both P‐value >.05). However, according to PGA and IGA, there was a significant difference in favor of sirolimus (P‐values =.041 and.039, respectively). Itching and dryness (86.7%), contact dermatitis (20%) were the most common adverse effects in the sirolimus group, while none of them were observed in placebo. Conclusion: Although the improvement was significant subjectively, topical sirolimus 0.2% as an adjuvant to PDL does not appear to improve PWS erythema using calorimetric assessment. [ABSTRACT FROM AUTHOR]

Rapamycin is an immunosuppressant that has been shown to prevent tumor growth following organ transplantation. However, its exact mode of antitumor action remains unknown. The present study used the B16-F10 (B16) murine melanoma model to explore the antitumor mechanism of rapamycin, and it was revealed that rapamycin reduced B16 cell viability in vitro and in vivo. In addition, in vitro and in vivo, the results of western blotting showed that rapamycin reduced Bcl2 expression, and enhanced the protein expression levels of cleaved caspase 3 and Bax, indicating that it can induce the apoptosis of B16 melanoma cells. Furthermore, the results of cell cycle analysis and western blotting showed that rapamycin induced B16 cell cycle arrest in the G1 phase, based on the reduction in the protein expression levels of CDK1, cyclin D1 and CDK4, as well as the increase in the percentage of cells in G1 phase. Rapamycin also significantly increased the number of autophagosomes in B16 melanoma cells, as determined by transmission electron microscopy. Furthermore, the results of RT-qPCR and western blotting showed that rapamycin upregulated the protein expression levels of microtubule-associated protein light chain 3 (LC3) and Beclin-1, while downregulating the expression of p62 in vitro and in vivo, thus indicating that rapamycin could trigger cellular autophagy. The present study revealed that rapamycin in combination with chloroquine (CQ) further increased LC3 expression compared with that in the CQ group, suggesting that rapamycin induced an increase in autophagy in B16 cells. Furthermore, the results of western blotting showed that rapamycin blocked the phosphorylation of p70 ribosomal S6 kinase (p70-S6k) and mammalian target of rapamycin (mTOR) proteins in vitro and in vivo, thus suggesting that rapamycin may exert its antitumor effect by inhibiting the phosphorylation of the mTOR/p70-S6k pathway. In conclusion, rapamycin may inhibit tumor growth by inducing cellular G1 phase arrest and apoptosis. In addition, rapamycin may exert its antitumor effects by inducing the autophagy of B16 melanoma cells in vitro and in vivo, and the mTOR/p70-S6k signaling pathway may be involved in this process. [ABSTRACT FROM AUTHOR]

After kidney transplantation, withdrawal of calcineurin inhibitors (CNI) and conversion to sirolimus (SRL) may reduce the occurrence of new non‐melanoma skin cancer (NMSC). Conversely, a reduced CNI exposure with everolimus (EVR) is an alternative strategy that has not been thoroughly evaluated. We retrospectively compared the occurrence of newly diagnosed NMSCs in two cohorts of kidney transplant recipients (KTR) with at least one NMSC: 35 patients were converted to EVR with reduced CNI exposure (CNI/EVR group), whereas 46 patients were converted to SRL in association with mycophenolic acid (MPA) (SRL/MPA group). Two years after conversion, survival free of new NMSC was similar between the two cohorts (p =.37), with 19 KTR (54.3%) in the CNI/EVR group and 22 (47.8%) in the SRL/MPA group being diagnosed of at least one new NMSC. Half of the KTR from both groups showed adverse events, leading to mTORi discontinuation for 37.1% of KTR in the CNI/EVR group and 21.7% in the SRL/MPA group (p =.09). The incidence of rejections was similar between the two groups. In a retrospective cohort of KTR with at least one post‐transplant NMSC, the outcome of the patients converted to a CNI/EVR regimen was not different from those converted to a SRL/MPA regimen. [ABSTRACT FROM AUTHOR]

Background and objective: To evaluate the safety and efficacy of intravitreal sirolimus for persistent, exudative age-related macular degeneration (AMD). Methods: This institutional review board approved, registered (NCT02357342), prospective, subject-masked, single center, randomized controlled trial in subjects with persistent, exudative Age-related macular degeneration compared intravitreal sirolimus monotherapy (every 2 months) versus monthly anti-vascular endothelial growth factor (VEGF) over six months. Results: 20 subjects were randomized to each arm of the trial. Upon completion of the trial 20 patients were analyzed in the control (anti-vascular endothelial growth factor) group and 17 patients were analyzed in the treatment (sirolimus) group. On average, subjects had 33 previous anti-VEGF injections prior to entry. The primary end-point, mean central subfield thickness (CST), increased by 20 µm in the anti-vascular endothelial growth factor group and decreased by 40 µm in the sirolimus group (p = 0.03). Visual acuity outcomes were similar between groups. Serious ocular adverse events in the sirolimus group included one subject each with anterior uveitis, central retinal artery occlusion and subretinal hemorrhage. Conclusion: Monotherapy with intravitreal sirolimus for subjects with persistent, exudative age-related macular degeneration appears to have a limited positive anatomic benefit. The presence of adverse events in the experimental group merits further evaluation, potentially as an adjuvant therapy. Trial registration This trial was registered with the clinicaltrials.gov, NCT02357342, and was approved by the institutional review board at Advarra. Funding was provided by an investigator-initiated grant from Santen. Santen played no role in the design or implementation of this study. [ABSTRACT FROM AUTHOR]

Introduction: The immunosuppressive efficiency obtained in the last decades in kidney transplantation significantly improved graft survival. However, there is still a high risk and incidence of cancer in transplant patients strongly and directly related to the type of immunosuppression. An increasing body of evidence suggests that the PI3K/Akt/mTOR pathway may play a pivotal role in the development and progression of several neoplastic diseases. Case Presentation: We describe a 47-year-old male patient who received a cadaveric primary renal transplant in November 2008 developing a poorly differentiated infiltrating and ulcerated squamous cell carcinoma (SCC) at the eye level. In this patient, the modification of an immunosuppressive regimen with introduction of rapamycin (mTOR) inhibitors and withdrawal of calcineurin inhibitors (CNIs) led to the resolution of this severe condition. Conclusion: The introduction of mTOR inhibitors and withdrawal of CNIs in kidney-transplanted patients with de novo eye SCC should be considered in this clinical setting. [ABSTRACT FROM AUTHOR]

Background: Rapamycin (RAPA) is a potent angiogenic inhibitor and the aim of this study is to identify the inhibitory effect of RAPA on retinal neovascularization (RNV) in experimental oxygen-induced retinopathy (OIR).Methods: Forty-two 7-day-old C57BL/6 J mice were randomly divided into normoxia control group (14 mice), OIR group (14 mice), and rapamycin (RAPA) group. OIR model was induced in OIR and RAPA group. Vehicle and RAPA (2 mg/kg/d) was injected intraperitoneally daily from postnatal day 12 (P12) in OIR and RAPA groups, respectively. RNV was evaluated using fluorescence angiography and histopathology on P17. Non-perfused areas of retina were analyzed by Image-Pro plus 6.0 software. Retinal expression of cyclin D1 was detected both at mRNA and protein levels.Results: RAPA treatment significantly decreased RNV, non-perfused areas and number of endothelial cell nuclei breaking through the internal limiting membrane (ILM) in OIR mice. Moreover, RAPA decreased activation of cyclin D1 in retina caused by OIR.Conclusion: RAPA can inhibit RNV by downregulating the expression of cyclin D1, which indicates its therapeutic potential in treating RNV-related diseases. [ABSTRACT FROM AUTHOR]

Previous studies have indicated that sirolimus (SRL) may be effective for HCC patients undergoing liver transplantation (LT). However, the following results are still contradictory and do not have a clear conclusion. Therefore, we conducted an updated meta-analysis by retrieving published data in EMBASE, PubMed, and the Cochrane Library up to October 2017. Both efficiency and safety of SRL were analyzed using pooled odds ratio (ORs) with 95% confidence interval (CIs). A total of 11 studies involving 7,695 HCC patients were included. Compared with control group, SRL prolonged 1-year (OR = 2.44; CI = 1.66–3.59), 3 year (OR = 1.67; CI = 1.08–2.58) and 5-year (OR = 1.68; CI = 1.21–2.33) overall survival, as well as 1-year (OR = 2.13; CI = 1.19–3.81) disease-free survival. Pooled results found that SRL-treated patients had lower recurrence (OR = 0.60; CI = 0.37–0.98), lower recurrence-related mortality (OR = 0.58; CI = 0.42–0.81) and lower overall mortality (OR = 0.62; CI = 0.44–0.89). Moreover, fewer SRL-treated patients suffered from portal vein thrombosis (OR = 0.29; CI, 0.09–0.91) and diabetes (OR = 0.23; CI = 0.12–0.47), while SRL-treated patients were more vulnerable to acne compared with the control group (OR = 4.44; CI = 1.56–12.60). No significant differences in other adverse effects were found between two groups. Taken together, SRL-based immunosuppression is safe and effective in improving survival, as well as reducing recurrence and mortality for HCC patients following LT. [ABSTRACT FROM AUTHOR]

Purpose: Although there is controversy, some evidences proposed increased risk of post-transplant Pneumocystis carinii pneumonia (PCP) in patients receiving mammalian target of rapamycin (mTOR) inhibitors. This study aimed to examine the association between m-TOR inhibitors and the risk of developing PCP in solid organ transplant (SOT) recipients. Methods: A comprehensive search was performed to find the eligible studies that investigated the incidence of PCP in patients treated with mTOR inhibitors after SOT. Random effect model was applied for meta-analysis. Results: Combination of 15 effect sizes showed a significant positive association between mTOR inhibitor administration and the risk of PCP (OR = 1.90, 95%CIs = 1.44, 2.75). There was no heterogeneity between studies (I2 = 3.5%). Subgroup analysis revealed increased risk of PCP after the first year of transplantation (P < 0.001). Conclusion: In conclusion, administration of mTOR inhibitors is a potential risk factor for late-onset PCP after SOT. Targeted PCP prophylaxis based on recipients' risk factors rather universal prophylaxis may lessen the risk. [ABSTRACT FROM AUTHOR]

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Click here for the corresponding questions to this CME article. [ABSTRACT FROM AUTHOR]

Rapamycin has been reported to be immunosuppressive and anti-proliferative towards vascular endothelial and smooth muscle cells. The purpose of the present study was to investigate the effects of rapamycin on the biological behaviors of endothelial cells that have been separated from the deformed vein in human venous malformation (VM). Cellular morphology was observed using inverted microscopy. An MTT assay was performed to measure the cell viability at different concentrations of rapamycin and different time points. Cell apoptosis and migration were detected using a terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling assay and a wound-healing assay, respectively. At 48 and 72 h, rapamycin inhibited proliferation of human VM endothelial cells, with the effects becoming more pronounced with increasing concentration. Only rapamycin at a concentration of 1,000 ng/ml had a significant effect at 24 h in repressing proliferation. At 48 h, compared with the blank group, the majority of cells maintained a clear nuclear boundary and a regular shape following treatment with 1 ng/ml rapamycin; 10 and 100 ng/ml rapamycin caused desquamation and rounded shape; and 1,000 ng/ml rapamycin caused even more marked desquamation, rounded shape and necrosis. Rapamycin at concentrations of 1, 10, 100 and 1,000 ng/ml reduced cell viability, increased the number of apoptotic cells and suppressed the migration capacity of human VM endothelial cells, and the effects became more pronounced with increasing concentration, when compared with the blank group. These findings provide evidence that rapamycin induces apoptosis and inhibits proliferation and migration of human VM endothelial cells in a concentration-dependent manner. [ABSTRACT FROM AUTHOR]

Allograft rejection is the major cause of corneal allograft failure. Rapamycin (RAPA) has been reported as an effective and novel immunosuppressive agent for patients undergoing corneal transplantation. However, its high water insolubility and low bioavailability have strongly constrained its clinical application. In this study, we successfully developed a RAPA nano-micelle ophthalmic solution and found that corneal allograft survival in recipients treated with RAPA nano-micelle ophthalmic solution was significantly prolonged for more than 2 months, with less inflammatory infiltration, decreased production of pro-inflammatory factors, and elevated recruitment of myeloid-derived suppressor cells (MDSCs). MDSCs from mice treated with RAPA nano-micelle ophthalmic solution could significantly inhibit the proliferation of CD4+T cells through increased expressions of inducible nitric oxidase (iNOS) and arginase-1 (Arg-1). The activity blockade of Arg-1 and iNOS pharmacologically reversed their immunosuppressive ability. Moreover, the effects of RAPA were antagonized by the administration of anti-Gr-1 antibody or by inhibiting the activity of iNOS pharmacologically. In addition, RAPA nano-micelle also effectively alleviated allograft rejection in high-risk rabbit penetrating keratoplasty (PKP) models with corneal vascularization. Collectively, our results demonstrate that RAPA nano-micelle ophthalmic solution could improve the immunosuppressive activity of MDSCs through elevated expression of Arg-1 and iNOS, which highlights the possible therapeutic applications of RAPA against corneal allograft rejection. [ABSTRACT FROM AUTHOR]

Although liver transplantation (LT) lengthens the survival time of patients with hepatocellular carcinoma (HCC), LT patients exhibit a high recurrence rate; particularly those that had advanced HCC associated with the tumor biological characteristics and long‑term application of immunosuppressants. A consensus on optimal prophylaxis and treatment for recurrent HCC following LT does not currently exist. The present study retrospectively analyzed data from 36 non‑University of California at San Francisco criteria‑eligible patients with advanced HCC who underwent LT, and then treated them with sirolimus (SRL)‑based therapy with thymalfasin and huaier granules (SRL+, n=18), or with tacrolimus‑based therapy (controls; n=18). The SRL+ group had significantly longer recurrence times (P=0.008) and survival times (P<0.0001) (OS, 1‑year: 100%, 3‑year: 94.4%, 5‑year: 77.8%; DFS, 1‑year: 88.9%, 3‑year: 55.6%, 5‑year: 50.0%). Furthermore, compared with pre‑LT values and the control group, the SRL+ group had significantly lower serum α‑fetoprotein (AFP) levels (both P<0.0001) and percentage of Forkhead box P3 (FoxP3)+ Treg lymphocytes (P<0.001) during the first year. In the SRL+ group, FoxP3+/cluster of differentiation (CD)8+ Treg lymphocyte percentages decreased significantly following LT (P<0.001); however, CD8+/CD3+ T‑cells significantly increased (P<0.001). Levels of serum AFP and FoxP3+ Treg cells increased when tumors relapsed, and decreased to near‑normal when relapse foci were cured or stabilized. SRL+ therapy may decrease AFP and Treg levels, while increasing CD8+ T cells, indicating an associated mechanism among them. In conclusion, SRL+ therapy appears to be safe and effective in preventing HCC recurrence following LT with no significant adverse events, and warrants further investigation. [ABSTRACT FROM AUTHOR]

Abstract: The mTOR inhibitor rapamycin is used systemically for the treatment of vascular lesions. We report the first use of topical rapamycin for the successful treatment of two cases of tufted angioma. The evidence for the use of topical rapamycin in other dermatologic conditions is summarized to aid in clinical decision making on preparations and anticipated side effects. [ABSTRACT FROM AUTHOR]

Abstract: Mammalian target of rapamycin complex 1 (mTORC1) kinase is a master regulator of the cellular response to nutrition‐related signals such as insulin and amino acids. mTORC1 is activated on the lysosomal membrane and induces phosphorylation of a variety of downstream molecules. We previously showed that activated mTORC1 induces protein phosphatase 2A (PP2A)‐mediated dephosphorylation of the transcription factor forkhead box K1 (FOXK1). The mechanism underlying the signal transduction from the cytoplasmic mTORC1 to the nuclear FOXK1 has remained unclear, however, we now show that a nuclear–cytoplasmic transport system is necessary for the mTORC1‐FOXK1 signal transduction. This reaction is mediated by a shuttling protein B56, which is a regulatory subunit of PP2A and plays an essential role in the mTORC1‐dependent dephosphorylation of FOXK1. These results suggest that PP2AB56 phosphatase contributes to the signaling for mTORC1‐dependent transcriptional regulation. [ABSTRACT FROM AUTHOR]

Introduction and aim. To investigate the effect of mTOR inhibitor Rapamycin combined with transcatheter arterial embolization (TAE) on the growth, metastasis, and prognosis of hepatocellular carcinoma (HCC) in rat model. Material and method. McARH7777 cells were used to construct rat models of HCC, which were randomly divided into Model, Rapamycin, TAE, and Rapamycin + TAE groups. Quantitative reverse transcription-PCR (qRT-PCR) and Western Blot were used to detect the expression of Epithelial-Mesenchymal Transition (EMT)-related molecules, and immunohistochemical staining to determine the expression of EMTrelated proteins, angiogenic factors as well as microvessel density (MVD)-CD34. Results. The hepatic tumor volume of rats in the other three groups were all significantly smaller than the Model group on the 7th, 14th, and 21st day after treatment and the combination treatment was apparently more effective than either treatment alone. Besides, both the number and the size of metastatic nodules of HCC rats after combination treatment were remarkably reduced. In addition, compared with rats in the Rapamycin + TAE group, N-cadherin, Vimentin, HIF-1a, VEGF, and MVD-CD34 were obviously enhanced, while E-cadherin was lowered in those TAE group, which were the complete opposite to the Rapamycin group. Besides, the median survival time of rats in the Rapamycin + TAE group was evidently longer than the resting groups. Conclusion. Rapamycin combined with TAE may effectively suppress the EMT formation and angiogenesis, thereby inhibiting the growth and lung metastasis of HCC rats, which provides a new idea for countering the recurrence and metastasis of HCC. [ABSTRACT FROM AUTHOR]

DEP domain-containing mechanistic target of rapamycin (mTOR)-interacting protein (DEPTOR) is an important modulator of mTOR, a kinase at the center of two important protein complexes named mTORC1 and mTORC2. These highly studied complexes play essential roles in regulating growth, metabolism, and immunity in response to mitogens, nutrients, and cytokines. Defects in mTOR signaling have been associated with the development of many diseases, including cancer and diabetes, and approaches aiming at modulating mTOR activity are envisioned as an attractive strategy to improve human health. DEPTOR interaction with mTOR represses its kinase activity and rewires the mTOR signaling pathway. Over the last years, several studies have revealed key roles for DEPTOR in numerous biological and pathological processes. Here, we provide the current state of the knowledge regarding the cellular and physiological functions of DEPTOR by focusing on its impact on the mTOR pathway and its role in promoting health and disease. [ABSTRACT FROM AUTHOR]

Background/Aims: Radiation therapy is an important and effective modality for the treatment of non-small cell lung cancer (NSCLC). MicroRNAs (miRNAs) are crucial post-transcriptional regulators that are involved in numerous important biologic processes. However, their potential involvement in radiation sensitivity remains unknown. Materials: We performed integrated analysis of miRNA expression in NSCLC using The Cancer Genome Atlas datasets. miR-99a was found to be significantly upregulated in cancer tissue and regulated cell survival. Cell culture was used to assess the role of miR-99a in radiation sensitivity. We then used flow cytometry to examine the effects of miR-99a on the cell cycle and apoptosis in cells exposed to radiation. To identify gene targets of miR-99a, a bioinformatics approach was adopted, and the findings of this analysis were verified using luciferase reporter assays. Finally, an in vivo study was conducted to examine the effect of miR-99a on tumor volume in an NSCLC mouse model undergoing radiation therapy. Results: miR-99a was significantly upregulated in radiation-sensitive A549 cells compared with radiation-resistant A549 cells. miR-99a overexpression was shown to enhance radiosensitivity, while inhibition of miR-99a resulted in radioresistance of NSCLC cell lines in vitro and in vivo. In addition, by bioinformatics software analysis and luciferase assays, mammalian target of rapamycin (mTOR) was identified as a direct target of miR-99a. Furthermore, AZD2014, an inhibitor of mTOR, enhanced radiosensitivity and apoptosis in NSCLC cell lines, while mTOR overexpression resulted in radioresistance and cell survival from miR-99a-induced cell apoptosis. Moreover, miR-99a overexpression further increased the efficacy of radiation therapy in an NSCLC xenograft mouse model, and miR-99a and mTOR expression was significantly inversely correlated. Conclusions: Altogether, these data suggested miR-99a functions as a tumor suppressor that has a critical role in regulating radiosensitivity of NSCLC by targeting the mTOR signaling pathway. [ABSTRACT FROM AUTHOR]

The use of sirolimus and its analogs has been evaluated for the treatment of different cancer types. The stability studies of sirolimus enabled to determine the kinetics of its chemical reactions in solid state and in the liquid medium. During intrinsic stability tests in a liquid medium, sirolimus showed a lack of stability when exposed to heat, neutral and basic hydrolysis. Analysis by high-performance liquid chromatography detected: two degradation products after exposure to heat; one degradation product for both basic and neutral hydrolyses; and all degradation products exhibited UV spectra similar to the drug's spectrum. Kinetics studies in a liquid medium revealed low drug stability in methanolic solution; this instability may be exacerbated in the presence of water or high pH. The application of solid-state kinetic models showed that the drug degrades in accordance with the diffusion dimensional model, with greater stability and an expiration date equal to 6 years, demonstrating that sirolimus has satisfactory stability in the solid state. Through this understanding, it is possible to develop more stable pharmaceutical formulations using sirolimus. [ABSTRACT FROM AUTHOR]

Mild traumatic brain injury (mTBI), common in juveniles, has been reported to be caused by sports-related concussion. Many young children may suffer from post-concussion syndrome. mTBI, in early stages of life, could play a part in neuron apoptosis and degeneration, cognitive and motor coordination impairment, as well as dementia. Our study was aimed at further investigating the post-therapeutic efficacy of rapamycin in the recuperation of mTBI while at the same time investigating the metamorphosis in both autophagy and mitophagy in mTBI. We created a weight-drop rat mTBI model with the administration of rapamycin at 4 h after every mTBI. Behavioral tests of beam walking and open field task indicated the expected improvement of cognitive and motor coordination functions. Both Western blot and immunofluorescence examinations revealed increased Beclin-1 and PINK1 in the treated rats as well as reduction of caspase-3 and cytochrome C (Cyt C). More so, the TUNEL staining evidenced curtailment of apoptotic cells following treatment with rapamycin. The upregulation of Beclin-1 and PINK1 and the downregulation of caspase-3 and Cyt C extrapolate that rapamycin plays neuroprotective as well as anti-apoptotic role via interposition of both autophagy and mitophagy. [ABSTRACT FROM AUTHOR]

Objective(s):Rapamycin is an immunosuppressant compound with a broad spectrum of pharmacological activities. In recent years, it has been used successfully to decrease ischemia-reperfusion injury in several organ systems. The purpose of the present study was to examine the effect of rapamycin on testicular ischemia-reperfusion injury. Materials and Methods: Seventy-two adult male Wistar rats were divided into six groups: control (group1), sham-operated (Group2), T/D + DMSO as vehicle group (group3), and groups 4-6; respectively received 0.5, 1, and 1.5 mgkg-1 of rapamycin, IP 30 min before detorsion. Ischemia was achieved by twisting the right testis 720° clockwise for 1 hr. The right testis of 6 animals from each group were excised 4 hr after detorsion for the measurement of lipid peroxidation, caspase-3, and antioxidant enzyme activities. Histopathological changes and germ cell apoptosis were determined by measuring mean of seminiferous tubules diameters (MSTD) and TUNEL test in right testis of 6 animals per group, 24 hr after detorsion. Results: Testicular T/D caused increases in the apoptosis, malondialdehyde (MDA), and caspase-3 levels and decreases in the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities in ipsilateral testis (P<0.001). The rats treated with rapamycin had significant decreases in the MDA and caspase-3 levels and significant increases in the SOD, CAT and GPx activities in ipsilateral testis compared with the T/D group (P<0.001); germ cell apoptosis was decreased, and MSTD was improved. Conclusion: Rapamycin administration during testicular torsion decreased ischemia/reperfusion (I/R) cellular damage. [ABSTRACT FROM AUTHOR]

In patients with refractory cancer, the effect of additional chemotherapy is very limited. Targeted agents for molecular pathways associated with cancer cell progression and survival have emerged as attractive options in several cancer types. The current pilot study assessed the efficacy and safety of sirolimus in patients with refractory cancer with PIK3CA mutation/amplification. Refractory cancer patients with PIK3CA mutation/amplification were enrolled, irrespective of tumor-types. Enrolled patients received a daily dose of 1 mg sirolimus and one cycle defined as 28 days. An assessment of the efficacy and safety of sirolimus was performed. Overall, 4 patients were enrolled between October 2014 and April 2015. The median of 2.5 cycles of sirolimus was administered. Three patients had advanced gastric cancer and one had advanced cholangiocarcinoma. The overall response rate was 0%, three patients (75%) had stable disease following one cycle and one patient (25%) received sirolimus for 4 cycles without disease progression. The median progression free survival was 1.9 months [95% confidence interval (CI), 0.3-3.5 months], and the median overall survival was 3.6 months (95% CI, 0.4-6.8 months). Grade 3 or greater hematologic/non-hematologic toxicity was not observed. Grade 1 nausea was reported in one patient each. There were no treatment-associated mortalities. Sirolimus had modest efficacy and a tolerable toxicity-profile in patients with refractory cancer with PIK3CA mutation/amplification. [ABSTRACT FROM AUTHOR]

Background: The ability to image vascular endothelial growth factor (VEGF) could enable prospective, non-invasive monitoring of patients receiving anti-angiogenic therapy. This study investigates the specificity and pharmacokinetics of In-bevacizumab binding to VEGF and its use for assessing response to anti-angiogenic therapy with rapamycin. Specificity of In-bevacizumab binding to VEGF was tested in vitro with unmodified radiolabelled bevacizumab in competitive inhibition assays. Uptake of In-bevacizumab in BALB/c nude mice bearing tumours with different amounts of VEGF expression was compared to that of isotype-matched control antibody (In-IgG1κ) with an excess of unlabelled bevacizumab. Intratumoural VEGF was evaluated using ELISA and Western blot analysis. The effect of anti-angiogenesis therapy was tested by measuring tumour uptake of In-bevacizumab in comparison to In-IgG1κ following administration of rapamycin to mice bearing FaDu xenografts. Uptake was measured using gamma counting of ex vivo tumours and effect on vasculature by using anti-CD31 microscopy. Results: Specific uptake of In-bevacizumab in VEGF-expressing tumours was observed. Rapamycin led to tumour growth delay associated with increased relative vessel size (8.5 to 10.3, P = 0.045) and decreased mean relative vessel density (0.27 to 0.22, P = 0.0015). Rapamycin treatment increased tumour uptake of In-bevacizumab (68%) but not In-IgGκ and corresponded with increased intratumoural VEGF. Conclusions: In-bevacizumab accumulates specifically in VEGF-expressing tumours, and changes after rapamycin therapy reflect changes in VEGF expression. Antagonism of mTOR may increase VEGF in vivo, and this new finding provides the basis to consider combination studies blocking both pathways and a way to monitor effects. [ABSTRACT FROM AUTHOR]

Objective: Unusual or unexpected effect of treatment Background: Benign multicystic peritoneal mesothelioma (BMPM) is a rare intra-abdominal tumor. Although considered by many to be benign, this tumor has a high local recurrence rate. Because of its rarity, preoperative diagnosis is difficult and its origin and pathogenesis are uncertain. There are no evidence-based treatment strategies for BMPM. It is agreed that the best treatment strategy for BMPM is the combination of surgical cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC). An increasing body of evidence supports a pivotal role of the cytoplasmic serine/threonine kinase mTOR in the development and progression of several neoplastic diseases and specific mTOR inhibitors, including rapamycin, have been suggested as potential therapeutic options for different cancers. Case Report: A 65-year-old male with end-stage renal disease on hemodialysis for seven years presented with BMPM. He underwent surgery to remove multiple peritoneal cysts, but four months later he experienced a recurrence of the disease. Immunohistochemistry of the cysts demonstrated a high level of phosphorylation of p70S6 kinase, a downstream mTOR target, and since a target therapy that blocks PI3K/Akt/mTOR pathway has been shown to have a scientific and logical rationale to treat this rare intra-abdominal neoplasia, we started the patient on low dose rapamycin therapy, an mTOR inhibitor. Long-term mTOR inhibition resulted in a complete and stable remission of BMPM. Conclusions: The current case is the first report of BMPM successfully treated with rapamycin, which resulted in a long-lasting response to mTOR inhibition. [ABSTRACT FROM AUTHOR]

ABSTRACT Rapamycin is an inhibitor of the mammalian target of rapamycin (mTOR) signaling pathway, plays an important role in multiple cellular functions. Our previous study showed rapamycin treatment in acute phase reduced the neural tissue damage and locomotor impairment after spinal cord injury (SCI). However, there has been no study to investigate the therapeutic effect of rapamycin on neuropathic pain after SCI. In this study, we examined whether rapamycin reduces neuropathic pain following SCI in mice. We used a mouse model of thoracic spinal cord contusion injury, and divided the mice into the rapamycin-treated and the vehicle-treated groups. The rapamycin-treated mice were intraperitoneally injected with rapamycin (1 mg/kg) 4 h after SCI. The rapamycin treatment suppressed phosphorylated-p70S6K in the injured spinal cord that indicated inhibition of mTOR. The rapamycin treatment significantly improved not only locomotor function, but also mechanical and thermal hypersensitivity in the hindpaws after SCI. In an immunohistochemical analysis, Iba-1-stained microglia in the lumbar spinal cord was significantly decreased in the rapamycin-treated mice. In addition, the activity of p38 MAPK in the lumbar spinal cord was significantly attenuated by rapamycin treatment. Furthermore, phosphorylated-p38 MAPK-positive microglia was relatively decreased in the rapamycin-treated mice. These results indicated rapamycin administration in acute phase to reduce secondary neural tissue damage can contribute to the suppression of the microglial activation in the lumbar spinal cord and attenuate the development of neuropathic pain after SCI. The present study first demonstrated that rapamycin has significant therapeutic potential to reduce the development of neuropathic pain following SCI. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:93-103, 2017. [ABSTRACT FROM AUTHOR]

Background/Aims: Prior studies demonstrate that hypoxia inducible factor subtype 1α (HIF-1α) in retinal tissues is involved in development of diabetic retinopathy (DR). In this report, we particularly examined the role played by mammalian target of rapamycin (mTOR) in regulating expression of HIF-1α and its downstream pathway, namely vascular endothelial growth factor (VEGF). Methods: Streptozotocin (STZ) was systemically injected to induce hyperglycemia in rats. ELISA and Western Blot analysis were employed to determine the levels of HIF-1α and VEGF as well as expression of mTOR pathways in retinal tissues of control rats and STZ rats. Results: Our results show that HIF-1α and VEGF as well as VEGF receptor subtype 2 (VEGFR-2) were increased in STZ rats. Also, the protein expression of p-mTOR, mTORmediated phosphorylation of 4E-binding protein 4 (4E-BP1), p70 ribosomal S6 protein kinase 1 (S6K1) pathways were amplified in diabetic retina compared with controls. Blocking mTOR by using rapamycin significantly attenuated activities of HIF-1α and VEGF signaling pathways. Conclusion: Our data for the first time revealed specific signaling pathways engaged in the development of DR, including the activation of mTOR and HIF-1α-VEGF mechanism. Targeting one or more of these signaling molecules may present new opportunities for treatment and management of DR often observed in clinics. [ABSTRACT FROM AUTHOR]

Background/Aims: Prior studies demonstrate that hypoxia inducible factor subtype 1α (HIF-1α) in retinal tissues is involved in development of diabetic retinopathy (DR). In this report, we particularly examined the role played by mammalian target of rapamycin (mTOR) in regulating expression of HIF-1α and its downstream pathway, namely vascular endothelial growth factor (VEGF). Methods: Streptozotocin (STZ) was systemically injected to induce hyperglycemia in rats. ELISA and Western Blot analysis were employed to determine the levels of HIF-1α and VEGF as well as expression of mTOR pathways in retinal tissues of control rats and STZ rats. Results: Our results show that HIF-1α and VEGF as well as VEGF receptor subtype 2 (VEGFR-2) were increased in STZ rats. Also, the protein expression of p-mTOR, mTOR-mediated phosphorylation of 4E-binding protein 4 (4E-BP1), p70 ribosomal S6 protein kinase 1 (S6K1) pathways were amplified in diabetic retina compared with controls. Blocking mTOR by using rapamycin significantly attenuated activities of HIF-1α and VEGF signaling pathways. Conclusion: Our data for the first time revealed specific signaling pathways engaged in the development of DR, including the activation of mTOR and HIF-1α -VEGF mechanism. Targeting one or more of these signaling molecules may present new opportunities for treatment and management of DR often observed in clinics. [ABSTRACT FROM AUTHOR]

Neuroendocrine tumors (NETs) are a rare diverse group of malignancies occurring most commonly in the gastroenteropancreatic system and the lungs. The incidence of NETs is increasing worldwide; median survival for patients with metastatic NETs is 5-65 months. A growing body of evidence shows survival benefit in patients with advanced NETs (gastroenteropancreatic and lung) treated with mTOR inhibitor everolimus, with improvement in survival being demonstrated in the clinical trial and real-world setting. Everolimus has been shown to have a manageable safety profile, with the most common adverse events being stomatitis, rash, diarrhea, fatigue and infections. Due to the rarity of the condition, there are challenges in conducting clinical trials in these patients. Further research is required to clarify the role of adjuvant therapy, treatment sequencing and the use of multimodality treatments. [ABSTRACT FROM AUTHOR]

The macrolide rapamycin and its analogues (rapalogs) constitute the first generation of mammalian target of rapamycin (mTOR) inhibitors. Since the introduction of rapamycin as an immunosuppressant, there has been extensive progress in understanding its complex mechanisms of action. New insights into the function of mTOR in different immune cell types, vascular endothelial cells and neoplastic cells have opened new opportunities and challenges regarding mTOR as a pharmacological target. Currently, the two known mTOR complexes, mTOR complex (mTORC) 1 and mTORC2, are the subject of intense investigation, and the introduction of second-generation dual mTORC kinase inhibitors (TORKinibs) and gene knockout mice is helping to uncover the distinct roles of these complexes in different cell types. While the pharmacological profiling of rapalogs is advanced, much less is known about the properties of TORKinibs. A potential benefit of mTOR inhibition in transplantation is improved protection against transplant-associated viral infections compared with standard calcineurin inhibitor-based immunosuppression. Preclinical and clinical data also underscore the potentially favourable antitumour effects of mTOR inhibitors in regard to transplant-associated malignancies and as a novel treatment option for various other cancers. Many aspects of the mechanisms of action of mTOR inhibitors and their clinical implications remain unknown. In this brief review we discuss new findings and perspectives of mTOR inhibitors in transplantation. [ABSTRACT FROM AUTHOR]

The mechanistic target of rapamycin (mTOR), via its two distinct multiprotein complexes, mTORC1, and mTORC2, plays a central role in the regulation of cellular growth, metabolism, and migration. A dysregulation of the mTOR pathway has in turn been implicated in several pathological conditions including insulin resistance and cancer. Overactivation of mTORC1 and disruption of mTORC2 function have been reported to induce insulin resistance. On the other hand, aberrant mTORC1 and mTORC2 signaling via either genetic alterations or increased expression of proteins regulating mTOR and its downstream targets have contributed to cancer development. These underlined the attractiveness of mTOR as a therapeutic target to overcome both insulin resistance and cancer. This review summarizes the evidence supporting the notion of intermittent, low dose rapamycin for treating insulin resistance. It further highlights recent data on the continuous use of high dose rapamycin analogs and related second generation mTOR inhibitors for cancer eradication, for overcoming chemoresistance and for tumor stem cell suppression. Within these contexts, the potential challenges associated with the use of mTOR inhibitors are also discussed. [ABSTRACT FROM AUTHOR]