sirolimus and Pain

Lingual microcystic lymphatic malformations (LMLMs) are rare congenital vascular malformations presenting as clusters of cysts filled with lymph fluid or blood. Even small well-limited lesions can be responsible for a heavy burden, inducing pain, aesthetic prejudice, or oozing, bleeding, infections. The natural history of LMLMs is progressive worsening punctuated by acute flares. Therapeutic options include surgery, laser excision, and radiofrequency ablation but all are potentially detrimental and expose to local relapse. Therefore, the management frequently relies on a "watchful waiting" approach. In complicated LMLMs, treatment with oral sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, is often used. Topical applications of sirolimus on the buccal mucosae have been reported in other oral diseases with good tolerance and none to slight detectable blood sirolimus concentrations. We aim to evaluate the efficacy and safety of a 1 mg/mL sirolimus solution applied once daily on LMLM of any stage in children and adults after 4, 8, 12, 16, 20, and 24 weeks of treatment compared to usual care (no treatment).. This is a randomized, multicentric study using an individually randomized stepped-wedge design over 24 weeks to evaluate topical application of a 1 mg/mL sirolimus solution once daily, on LMLM, versus usual care (no treatment), the control condition. Participants begin with an observational period and later switch to the intervention at a randomized time (week 0, 4, 8, or 12). Visits occur every 4 weeks, either in the study center or by teleconsulting. The primary outcome will be the evaluation of global severity of the LMLM on monthly standardized photographs by 3 independent blinded experts using the physical global assessment (PGA) 0 to 5 scale. Secondary outcomes will include lesion size measurement and quality of life assessment, investigator, and patient-assessed global disease and specific symptoms (oozing, bleeding, sialorrhea, eating impairment, taste modification, aesthetic impairment, pain, and global discomfort) assessment. A biological monitoring will be performed including residual blood sirolimus concentration and usual laboratory parameters.. Given the disappointing state of current treatment options in LMLMs, topical sirolimus could become firstline therapy in treating LMLMs if its efficacy and safety were to be demonstrated.. ClinicalTrials.gov NCT04128722 . Registered on 24 September 2019. EudraCT: EUCTR2019-001530-33-FR Sponsor (University Hospital Center of Tours - CHRU Tours): DR190041-TOPGUN French regulatory authorities: ID RCB: 2019-001530-33.

Topics: Adult; Child; Cysts; Humans; Immunosuppressive Agents; Lymphatic Abnormalities; Multicenter Studies as Topic; Neoplasm Recurrence, Local; Pain; Quality of Life; Randomized Controlled Trials as Topic; Sirolimus; Treatment Outcome

The multicentre, open-label, two-stage, single-arm, phase 2, PILLAR (PIvotaL Lymphoma triAls of RAD001)-1 study (NCT00702052) assessed the efficacy and safety of everolimus 10 mg/d in adults with confirmed mantle cell lymphoma (MCL) refractory to or intolerant of bortezomib who received ≥1 other antineoplastic agent, either separately or in combination with bortezomib. Primary endpoint was overall response rate (ORR) per investigator review according to the response criteria for malignant lymphoma. Secondary endpoints included progression-free survival (PFS), overall survival (OS) and safety. Fifty-eight patients were enrolled from August 2008-January 2011. Five partial responses were observed (ORR 8·6%; 90% confidence interval [CI] 3·5-17·3%); the study did not meet the prespecified objective of ≥8 objective responses among 57 patients. Median PFS and OS were 4·4 months (95% CI 3·5-6·1) and 16·9 months (95% CI 14·4-29·9), respectively. Grade 3/4 non-haematological toxicities occurred in 70·7% of patients. Based on laboratory values, grade 3/4 thrombocytopenia, neutropenia and anaemia occurred in 13·8%, 13·8% and 8·6% of patients, respectively. Everolimus demonstrated modest activity and acceptable tolerability in heavily pretreated patients with MCL refractory to or intolerant of bortezomib. Future studies evaluating everolimus in a less refractory population or in combination with other targeted therapies in refractory MCL are warranted.

Topics: Adult; Aged; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Boronic Acids; Bortezomib; Combined Modality Therapy; Disease-Free Survival; Drug Resistance, Neoplasm; Everolimus; Female; Gastrointestinal Diseases; Hematologic Diseases; Humans; Kaplan-Meier Estimate; Lymphoma, Mantle-Cell; Male; Middle Aged; Pain; Pneumonia; Pyrazines; Salvage Therapy; Sirolimus; Treatment Outcome

Everolimus is an oral raptor mTOR inhibitor and has shown activity in patients with Waldenstrom's macroglobulinemia (WM). This study examines a large cohort of patients with relapsed/refractory WM with long-term follow up for survival. Patients were eligible if they had measurable disease, a platelet count >75,000 x 10(6)/L, an absolute neutrophil count >1,000 x 10(6)/L. Patients received everolimus 10 mg PO daily and were evaluated monthly. A success was defined as a complete or partial response (PR); minor responses (MR) were recorded and considered to be of clinical benefit. Sixty patients were enrolled and treated. The overall response rate (ORR) was 50% (all PR); the clinical benefit rate including MR or better was 73% (95% CI: 60-84%) with 23% MR. The median time to response for patients who achieved PR was 2 months (range, 1-26). The median duration of response has not been reached and median progression-free survival (PFS) was 21 months. Grade 3 or higher toxicities (at least possibly related to everolimus) were observed in 67% of patients. The most common grade 3 or 4 toxicities were anemia (27%), leukopenia (22%), and thrombocytopenia (20%). Other nonhematological toxicities were diarrhea (5%), fatigue (8%), stomatitis (8%) and pulmonary toxicity (5%). Everolimus has a high single-agent activity of 73% including MR, with a progression free survival of 21 months, indicating that this agent is active in relapsed/refractory WM.

Topics: Adult; Aged; Aged, 80 and over; Alkylating Agents; Angiogenesis Inhibitors; Antibodies, Monoclonal, Murine-Derived; Antimetabolites; Bone Marrow; Diarrhea; Disease-Free Survival; Drug Resistance; Everolimus; Fatigue; Female; Hematologic Diseases; Humans; Immunoglobulin M; Kaplan-Meier Estimate; Male; Middle Aged; Pain; Paraproteins; Recurrence; Rituximab; Sirolimus; Stomatitis; TOR Serine-Threonine Kinases; Treatment Outcome; Waldenstrom Macroglobulinemia

Myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) is curative for children with severe sickle cell disease, but toxicity may be prohibitive for adults. Nonmyeloablative transplantation has been attempted with degrees of preparative regimen intensity, but graft rejection and graft-vs-host disease remain significant.. To determine the efficacy, safety, and outcome on end-organ function with this low-intensity regimen for sickle cell phenotype with or without thalassemia.. From July 16, 2004, to October 25, 2013, 30 patients aged 16-65 years with severe disease enrolled in this nonmyeloablative transplant study, consisting of alemtuzumab (1 mg/kg in divided doses), total-body irradiation (300 cGy), sirolimus, and infusion of unmanipulated filgrastim mobilized peripheral blood stem cells (5.5-31.7 × 10(6) cells/kg) from human leukocyte antigen-matched siblings.. The primary end point was treatment success at 1 year after the transplant, defined as a full donor-type hemoglobin for patients with sickle cell disease and transfusion independence for patients with thalassemia. The secondary end points were the level of donor leukocyte chimerism; incidence of acute and chronic graft-vs-host disease; and sickle cell-thalassemia disease-free survival, immunologic recovery, and changes in organ function, assessed by annual brain imaging, pulmonary function, echocardiographic image, and laboratory testing.. Twenty-nine patients survived a median 3.4 years (range, 1-8.6), with no nonrelapse mortality. One patient died from intracranial bleeding after relapse. As of October 25, 2013, 26 patients (87%) had long-term stable donor engraftment without acute or chronic graft-vs-host disease. The mean donor T-cell level was 48% (95% CI, 34%-62%); the myeloid chimerism levels, 86% (95% CI, 70%-100%). Fifteen engrafted patients discontinued immunosuppression medication with continued stable donor chimerism and no graft-vs-host disease. The normalized hemoglobin and resolution of hemolysis among engrafted patients were accompanied by stabilization in brain imaging, a reduction of echocardiographic estimates of pulmonary pressure, and allowed for phlebotomy to reduce hepatic iron. The mean annual hospitalization rate was 3.23 (95% CI, 1.83-4.63) the year before, 0.63 (95% CI, 0.26-1.01) the first year after, 0.19 (95% CI, 0-0.45) the second year after, and 0.11 (95% CI, 0.04-0.19) the third year after transplant. For patients taking long-term narcotics, the mean use per week was 639 mg (95% CI, 220-1058) of intravenous morphine-equivalent dose the week of their transplants and 140 mg (95% CI, 56-225) 6 months after transplant. There were 38 serious adverse events: pain and related management, infections, abdominal events, and sirolimus related toxic effects.. Among 30 patients with sickle cell phenotype with or without thalassemia who underwent nonmyeloablative allogeneic HSCT, the rate of stable mixed-donor chimerism was high and allowed for complete replacement with circulating donor red blood cells among engrafted participants. Further accrual and follow-up are required to assess longer-term clinical outcomes, adverse events, and transplant tolerance.. clinicaltrials.gov Identifier: NCT00061568.

Topics: Adolescent; Adult; Aged; Alemtuzumab; Anemia, Sickle Cell; Antibodies, Monoclonal, Humanized; beta-Thalassemia; Chimerism; Erythrocytes; Female; Filgrastim; Graft vs Host Disease; Granulocyte Colony-Stimulating Factor; Hematopoietic Stem Cell Mobilization; Hematopoietic Stem Cell Transplantation; HLA Antigens; Humans; Immunosuppressive Agents; Infections; Male; Middle Aged; Pain; Prospective Studies; Recombinant Proteins; Sirolimus; Transplantation Conditioning; Transplantation, Homologous; Treatment Outcome; Whole-Body Irradiation; Young Adult

A pediatric study has established a maximum tolerated dose (MTD) for temsirolimus (Tem) of more than 150 mg/m intravenously/week. A phase I trial was conducted to establish the MTD for Tem in combination with valproic acid (VPA) in children and adolescents with refractory solid tumors. The secondary aims included expression of mammalian target of rapamycin (mTOR) markers on archival tumor tissue; Tem pharmacokinetics; assessment of histone acetylation (HA); and tumor response. Patients were treated with VPA (5 mg/kg orally three times daily) with a target serum level of 75-100 mcg/ml. Tem was started at an initial dose of 60 mg/m/week. Pharmacokinetics and HA measurements were performed during weeks 1 and 5. Two of the first three patients experienced dose-limiting toxicity (grade 3 mucositis). Tem at 35 mg/m/week was found to be tolerable. Peak Tem concentrations were higher in all patients compared with those in previously published reports of single agent Tem. Increases in HA are correlated with VPA levels. All tumor samples expressed mTORC1 and mTORC2. An objective response was observed in one patient (melanoma), whereas transient stable disease was observed in four other patients (spinal cord ependymoma, alveolar soft part sarcoma, medullary thyroid carcinoma, and hepatocellular carcinoma). The MTD of Tem when administered with VPA is considerably lower than when used as a single agent, with mucositis the major dose-limiting toxicity. The combination merits further study and may have activity in melanoma. Attention to drug-drug interactions will be important in future multiagent trials including Tem.

Topics: Adolescent; Antineoplastic Combined Chemotherapy Protocols; Child; Child, Preschool; Diphenhydramine; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Eruptions; Early Termination of Clinical Trials; Fatigue; Female; Hematologic Diseases; Histone Deacetylase Inhibitors; Humans; Infusions, Intravenous; Male; Mucositis; Neoplasms; Pain; Sirolimus; Valproic Acid

The purpose of this study was to present our initial experience in using sirolimus therapy to treat fibro-adipose vascular anomaly (FAVA).. We retrospectively reviewed the medical records of eight patients with FAVA who were treated with sirolimus at our hospital between July 2017 and October 2020.. Six girls (75%) and two boys (25%) were included in the cohort; the average age was 8 years (range, 1-13 years). Vascular tumors developed mainly on the extremities, including the forearm (n = 2; 25.0%), calf (n = 4; 50.0%), and thigh (n = 2; 25.0%). The predominant symptoms included swelling of the lesion (n = 8; 100%), pain (n = 7; 87.5%), contracture (n = 3; 37.5%), and phlebectasia (n = 3; 37.5%). Magnetic resonance imaging was the primary method used for FAVA diagnosis, and all patients underwent enhanced MRI. All lesions were heterogeneous with hyperintense T1 signals. The fat-suppressed T2-weighted images also revealed heterogeneous hyperintense masses, thus indicating fibrofatty infiltration. All eight patients received a sirolimus treatment regimen after FAVA diagnosis. One patient underwent tumor resection but experienced recurrence, whereas the other six patients underwent biopsy. Histological examination revealed that the lesions consisted of fibrofatty tissue with abnormal venous channels and anomalous lymphatic vascular components. Sirolimus softened the masses and caused tumor shrinkage within 5.25 ± 2.6 weeks (range, 2-10 weeks) after treatment initiation. The tumors also involuted rapidly and became stable within 7.75 ± 2.25 months after treatment initiation (range, 6-12 months). All seven patients experiencing pain reported relief within 3.8 ± 1.8 weeks (range, 2-7 weeks) after initiation of sirolimus therapy. Sirolimus alleviated but did not fully resolve the contracture in three patients. Remarkably, five patients exhibited a complete response, and three patients exhibited a partial response. At the time of the last follow-up, three patients had begun to gradually taper off sirolimus after 24 months of treatment and maintained a low blood sirolimus concentration. No serious adverse effects were observed during treatment.. FAVA is a complex vascular malformation that appears to respond well to sirolimus treatment. Thus, sirolimus may be an effective and safe treatment for FAVA.. LEVEL IV.

Topics: Adolescent; Child; Child, Preschool; Contracture; Female; Humans; Infant; Lower Extremity; Male; Pain; Retrospective Studies; Sirolimus; Treatment Outcome; Vascular Malformations

The diagnosis and treatment of fibro-adipose vascular anomaly (FAVA) of the limb remains challenging since this entity is rare and complex. This paper is aimed to describe the clinical and imaging features, staging and management of this underrecognized disease of the limb.. Patients diagnosed with FAVA and managed between September 2019 and May 2022 in department of pediatric surgery & vascular anomalies of Xi'an international medical center hospital were retrospectively reviewed. Data extracted include age at presentation, previous diagnosis, affected muscles, symptoms, previous treatment, our management, and follow-up.. Thirty-two patients with FAVA were diagnosed and managed in our center. There was a female sex predominance, with 23 female (72%) and 9 male (28%) in the cohort. Only one lesion was noticed during infancy; the remaining presented at age 1 to 20 years (median, 7 years). The most commonly involved muscles were gastrocnemius (14/32, 44%) and soleus (13/32, 40%). Swelling (mass), pain and contractures were the most common presentations. MRI featured a heterogeneous and ill-defined intramuscular high signal intensity. Diseases were staged according to clinical features: stage I (pain stage, n = 4), stage II (contracture stage, n = 20) and stage III (deformity stage, n = 8). Patients with stage I disease underwent radical resection and obtained a cure. Patients with stage II disease received radical resection and possible Achilles lengthening, having an outcome of cure. Personalized treatment was required in patients with stage III disease, including radical/partial/staged resection, Achilles lengthening/tenotomy, joint capsulotomy, neurolysis/neurectomy, tendon transfer, stretching exercises, and oral sirolimus/alpelisib. Significant improvement of symptoms was achieved in most.. The most distinct features of FAVA include enlarging mass, severe pain and contracture. Based on distinct clinical and radiologic features, it is not difficult to make the diagnosis of FAVA. Earlier awareness of this disease can reduce misdiagnoses. Surgery-based comprehensive management can typically improve pain and contracture. Oral sirolimus or alpelisib plays an important role in treatment of unresectable lesions and major nerve involvement. Surgery alone can be curative in early stage FAVA.

Topics: Adolescent; Adult; Child; Child, Preschool; Contracture; Female; Humans; Infant; Male; Obesity; Pain; Retrospective Studies; Sirolimus; Treatment Outcome; Vascular Malformations; Young Adult

Topics: Administration, Topical; Adolescent; Anti-Inflammatory Agents; Biopsy; Crohn Disease; Drug Therapy, Combination; Female; Genitalia; Humans; Immunohistochemistry; Immunosuppressive Agents; Injections, Intralesional; Lymphedema; Pain; Pruritus; Sirolimus; Skin; Treatment Outcome; Triamcinolone; Warts

Animal experiment: a rat model of lumbar disc herniation (LDH) induced painful radiculopathies.. To investigate the role and mechanism of AMP-activated protein kinase (AMPK) in dorsal root ganglia (DRG) neurons in LDH-induced painful radiculopathies.. Overactivation of multiple pain signals in DRG neurons triggered by LDH is crucial to the development of radicular pain. AMPK is recognized as a cellular energy sensor, as well as a pain sensation modulator, but its function in LDH-induced pain hypersensitivity remains largely unknown.. The LDH rat model was established by autologous nucleus pulposus transplantation into the right lumbar 5 (L5) nerve root. At different time points after AMPK agonist metformin (250 mg/kg/d) or mammalian target of rapamycin (mTOR) inhibitor rapamycin (5 mg/kg) intraperitoneal administration, thermal and mechanical sensitivity were evaluated by measuring paw withdrawal latency (PWL) and 50% paw withdrawal thresholds (PWT). The levels of AMPK, mTOR, and p70S6K phosphorylation were determined by Western blot. We also investigated the proportion of p-AMPK positive neurons in the right L5 DRG neurons using immunofluorescence.. LDH evoked persistent thermal hyperalgesia and mechanical allodynia on the ipsilateral paw, as indicated by the decreased PWL and 50% PWT. These pain hypersensitive behaviors were accompanied with significant inhibition of AMPK and activation of mTOR in the associated DRG neurons. Pharmacological activation of AMPK in the DRG neurons not only suppressed mTOR/p70S6K signaling, but also alleviated LDH-induced pain hypersensitive behaviors.. We provide a molecular mechanism for the activation of pain signals based on AMPK-mTOR axis, as well as an intervention strategy by targeting AMPK-mTOR axis in LDH-induced painful radiculopathies.. N/A.

Topics: AMP-Activated Protein Kinases; Animals; Disease Models, Animal; Ganglia, Spinal; Hyperalgesia; Intervertebral Disc Degeneration; Intervertebral Disc Displacement; Male; Metformin; Neurons; Nucleus Pulposus; Pain; Phosphorylation; Radiculopathy; Rats; Rats, Wistar; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus; Spinal Nerve Roots; TOR Serine-Threonine Kinases

Mammalian target of rapamycin complex 1 (mTORC1) inhibitors increase the incidence of pain in patients, and this finding has been replicated in animal models. However, reports on possible analgesics for this condition are scant. Accumulating evidence finds that nicotinic acetylcholine receptors (nAChRs) are involved in mediating pain. However, whether nicotine, a full agonist of nAChRs, alleviates mTORC1 inhibition-induced pain and its underlying mechanisms remain unknown. In this study, pain was induced in naïve male C57BL/6J mice by intraperitoneally injecting rapamycin acutely or repeatedly. Subsequently, pain thresholds, including mechanical and thermal pain, were measured. The involving signaling pathway was tested using western blot analysis and immunofluorescent assay. Changes in neuronal excitability caused by different treatments were also analyzed using whole-cell recording. Microinjection into the anterior cingulate cortex (ACC) was used to test the role of nAChRs containing the α4β2 or α7 subtype in this brain region in pain modulation. Our results showed that nicotine significantly reduced hyperalgesia in mice that received acute or repeated rapamycin injections, and reversed the effects of rapamycin on the phosphorylation of S6K, 4E-BP1, insulin receptor substrate-1 (IRS-1) at Ser636/639, AKT at Ser473, and ERK at Thr202/Tyr204. Whole-cell recording results showed that nicotine reduced the firing rates of pyramidal neurons in the ACC, and a pharmacological blockade of nAChRs containing the α4β2 or α7 subtype in ACC inhibited the antinociceptive effects of nicotine in mice with rapamycin-induced pain. Our findings indicate that analgesics targeting nAChRs can be developed to help patients with rapamycin-induced pain.

Topics: Analgesics; Animals; Insulin Receptor Substrate Proteins; Male; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Inbred C57BL; Nicotine; Pain; Pain Threshold; Phosphorylation; Proto-Oncogene Proteins c-akt; Receptors, Nicotinic; Ribosomal Protein S6 Kinases, 90-kDa; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Topics: Administration, Cutaneous; Antibiotics, Antineoplastic; Female; Humans; Keratoderma, Palmoplantar; Middle Aged; Pachyonychia Congenita; Pain; Sirolimus

Fibroadipose vascular anomaly (FAVA) is a rare, complex mesenchymal malformation combining fibrofatty replacement of the affected muscles and slow-flow vascular malformation. The condition is characterized by localized swelling, severe pain, phlebectasia, and contracture of the affected limb. Treatment paradigms are not well established for this rare, recently recognized condition. We report two cases of FAVA in which treatment with sirolimus produced rapid, dramatic improvement in pain and quality of life.

Topics: Adolescent; Child; Female; Foot; Forearm; Humans; Immunosuppressive Agents; Magnetic Resonance Imaging; Muscle, Skeletal; Pain; Pain Management; Quality of Life; Sirolimus; Treatment Outcome; Vascular Malformations

The current study was to examine the underlying mechanisms responsible for the role of mammalian target of rapamycin (mTOR) in regulating bone cancer-evoked pain and the tolerance of systemic morphine. Breast sarcocarcinoma Walker 256 cells were implanted into the tibia bone cavity of rats and this evoked significant mechanical and thermal hyperalgesia. Our results showed that the protein expression of p-mTOR, mTOR-mediated phosphorylation of 4E-binding protein 4 (4E-BP1), p70 ribosomal S6 protein kinase 1 (S6K1) as well as phosphatidylinositide 3-kinase (p-PI3K) pathways were amplified in the superficial dorsal horn of the spinal cord of bone cancer rats compared with control rats. Blocking spinal mTOR by using rapamycin significantly attenuated activities of PI3K signaling pathways as well as mechanical and thermal hyperalgesia. Additionally, rapamycin enhanced attenuations of protein kinase Cɛ (PKCɛ)/protein kinase A (PKA) induced by morphine and further extended analgesia of morphine via µ-opioid receptor (MOR). Our data for the first time revealed specific signaling pathways leading to bone cancer pain, including the activation of mTOR and PI3K and downstream PKCɛ/PKA, and resultant sensitization of MOR. Targeting one or more of these signaling molecules may present new opportunities for treatment and management of bone cancer pain often observed in clinics.

Topics: Analgesics, Opioid; Animals; Blotting, Western; Bone Neoplasms; Disease Models, Animal; Drug Tolerance; Morphine; Pain; Rats; Rats, Wistar; Receptors, Opioid, mu; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Topics: Cancer Pain; Humans; Pain; Sirolimus

Bladder disorders associated with interstitial cystitis are frequently characterized by increased contractility and pain. The purposes of this study were to examine (1) the effects of blocking mammalian target of rapamycin (mTOR) on the exaggerated bladder activity and pain evoked by cystitis and (2) the underlying mechanisms responsible for the role of mTOR in regulating cystic sensory activity.. The expression of p-mTOR, mTOR-mediated phosphorylation of p70 ribosomal S6 protein kinase 1 (p-S6K1), 4 E-binding protein 4 (p-4 E-BP1), as well as phosphatidylinositide 3-kinase (p-PI3K) pathway were amplified in cyclophosphamide rats as compared with control rats. Blocking mTOR by intrathecal infusion of rapamycin attenuated bladder hyperactivity and pain. In addition, blocking PI3K signal pathway attenuated activities of mTOR, which was accompanied with decreasing bladder hyperactivity and pain. Inhibition of either mTOR or PI3K blunted the enhanced spinal substance P and calcitonin gene-related peptide in cyclophosphamide rats.. The data for the first time revealed specific signaling pathways leading to cyclophosphamide-induced bladder hyperactivity and pain, including the activation of mTOR and PI3K. Inhibition of these pathways alleviates cystic pain. Targeting one or more of these signaling molecules may present new opportunities for treatment and management of overactive bladder and pain often observed in cystitis.

Topics: Animals; Calcitonin Gene-Related Peptide; Chromones; Cyclophosphamide; Cystitis; Disease Models, Animal; Enzyme Inhibitors; Female; Hypersensitivity; Immunosuppressive Agents; Morpholines; Pain; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus; Urinary Bladder

Mammalian target of rapamycin (mTOR) is a serine-threonine protein kinase that controls protein synthesis in the nervous system. Here, we characterized the role of protein synthesis regulation due to mTOR signaling in rat dorsal root ganglion (DRG) following plantar incision. The number of phosphorylated mTOR (p-mTOR)-positive neurons was increased 2-4days after the incision. Rapamycin inhibited p-mTOR expression in the DRG and thermal hypersensitivity 3days but not 1day after the incision. Vesicular glutamate transporter 2 (VGLUT2) expression was increased after the plantar incision, which was inhibited by rapamycin. These results demonstrated that tissue injury induces phosphorylation of mTOR and increased protein level of VGLUT2 in the DRG neurons. mTOR phosphorylation involves in maintenance of injury-induced thermal hypersensitivity.

Topics: Analgesics; Animals; Disease Models, Animal; Foot Injuries; Ganglia, Spinal; Hindlimb; Hot Temperature; Hyperalgesia; Male; Neurons; Pain; Pain Threshold; Phosphorylation; Posterior Horn Cells; Rats, Sprague-Dawley; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; TRPV Cation Channels; Vesicular Glutamate Transport Protein 2

The mammalian target of rapamycin (mTOR) pathway is essential for maintenance of the sensitivity of certain adult sensory neurons. Here, we investigated whether the mTOR cascade is involved in scorpion envenomation-induced pain hypersensitivity in rats. The results showed that intraplantar injection of a neurotoxin from Buthus martensii Karsch, BmK I (10 μg), induced the activation of mTOR, as well as its downstream molecules p70 ribosomal S6 protein kinase (p70 S6K) and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), in lumbar 5-6 dorsal root ganglia neurons on both sides in rats. The activation peaked at 2 h and recovered 1 day after injection. Compared with the control group, the ratios of p-mTOR/p-p70 S6K/p-4EBP1 in three types of neurons changed significantly. The cell typology of p-mTOR/p-p70 S6K/p-4E-BP1 immuno-reactive neurons also changed. Intrathecal administration of deforolimus, a specific inhibitor of mTOR, attenuated BmK I-induced pain responses (spontaneous flinching, paroxysmal pain-like behavior, and mechanical hypersensitivity). Together, these results imply that the mTOR signaling pathway is mobilized by and contributes to experimental scorpion sting-induced pain.

Topics: Animals; Ganglia, Spinal; Male; Nociception; Pain; Phosphorylation; Rats; Rats, Sprague-Dawley; Scorpion Venoms; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

In advanced breast cancer, bone metastases occur in 70 % of patients. Managing the devastating pain associated with the disease is difficult. Rapamycin is an immunomodulatory drug that targets the mammalian target of rapamycin pathway. Rapamycin has been shown to decrease osteolysis associated with metastatic breast cancer in pre-clinical models and to reduce pain in inflammatory and neuropathic models. The aim of this study was to evaluate the effectiveness of rapamycin in reducing pain associated with experimental osteolytic metastases. Bone cancer was induced by intra-tibial injections of murine mammary carcinoma cells (4T1) in immunocompetent BALB/c mice and treated intraperitoneally for up to 5 weeks with vehicle, rapamycin or pamidronate (a bisphosphonate currently used to reduce bone loss in bone cancer patients). The control group received intra-tibial injection with saline (sham) and was treated with vehicle intraperitoneally. Cancer-induced osteolysis was observed histologically and radiographically 2-3 weeks following cancer inoculation and gradually increased with time. Measures of evoked nociceptive behaviors including sensitivity to mechanical, thermal, and cold stimuli and spontaneous nociceptive behaviors (limping, guarding) were evaluated. Significant hypersensitivity to sensory stimuli developed in cancer-bearing mice compared to sham 3 weeks following inoculation. Rapamycin decreased or delayed the development of cancer-induced mechanical, heat, and cold hypersensitivity, while pamidronate reduced heat and cold hypersensitivity. Both rapamycin and pamidronate had a partial protective effect on the spontaneous nociceptive behaviors, limping and guarding. Our data suggest that rapamycin may have efficacy in the management of pain associated with metastatic breast cancer.

Topics: Animals; Antibiotics, Antineoplastic; Bone Density Conservation Agents; Bone Neoplasms; Cell Line, Tumor; Diphosphonates; Disease Models, Animal; Female; Mammary Neoplasms, Experimental; Mice; Mice, Inbred BALB C; Osteolysis; Pain; Pain Measurement; Pamidronate; Sirolimus; TOR Serine-Threonine Kinases

The development of opioid-induced analgesic tolerance and hyperalgesia is a clinical challenge for managing chronic pain. Adaptive changes in protein translation in the nervous system are thought to promote opioid tolerance and hyperalgesia; however, how opioids drive such changes remains elusive. Here, we report that mammalian target of rapamycin (mTOR), which governs most protein translation, was activated in rat spinal dorsal horn neurons after repeated intrathecal morphine injections. Activation was triggered through μ opioid receptor and mediated by intracellular PI3K/Akt. Spinal mTOR inhibition blocked both induction and maintenance of morphine tolerance and hyperalgesia, without affecting basal pain perception or locomotor functions. These effects were attributed to the attenuation of morphine-induced increases in translation initiation activity, nascent protein synthesis, and expression of some known key tolerance-associated proteins, including neuronal NOS (nNOS), in dorsal horn. Moreover, elevating spinal mTOR activity by knocking down the mTOR-negative regulator TSC2 reduced morphine analgesia, produced pain hypersensitivity, and increased spinal nNOS expression. Our findings implicate the μ opioid receptor-triggered PI3K/Akt/mTOR pathway in promoting morphine-induced spinal protein translation changes and associated morphine tolerance and hyperalgesia. These data suggest that mTOR inhibitors could be explored for prevention and/or reduction of opioid tolerance in chronic pain management.

Topics: Animals; Cell Proliferation; Dose-Response Relationship, Drug; Drug Tolerance; Hyperalgesia; Injections, Spinal; Male; Mechanistic Target of Rapamycin Complex 1; Morphine; Multiprotein Complexes; Neurons; Pain; Pain Management; Phosphatidylinositol 3-Kinases; Rats; Rats, Sprague-Dawley; Receptors, Opioid, mu; Sirolimus; Spinal Cord; Spleen; Time Factors; TOR Serine-Threonine Kinases

Mammalian target of rapamycin complex 1 (mTORC1) inhibitors are extensively used as immunosuppressants to prevent transplant rejection and in treatment of certain cancers. In patients, chronic treatment with rapamycin or its analogues (rapalogues) has been reported to lead to sensory hypersensitivity and pain conditions via an unknown mechanism. Here, we show that pharmacological or genetic inhibition of mTORC1 activates the extracellular signal-regulated kinase (ERK) pathway in sensory neurons via suppression of S6K1 to insulin receptor substrate 1 negative feedback loop. As a result, increased ERK activity induces sensory neuron sensitization, mechanical hypersensitivity, and spontaneous pain. The clinically available adenosine monophosphate-activated protein kinase activator, metformin, which is an antidiabetic drug, prevents rapamycin-induced ERK activation and the development of mechanical hypersensitivity and spontaneous pain. Taken together, our findings demonstrate that activation of the ERK pathway in sensory neurons as a consequence of mTORC1 inhibition leads to the development of pain. Importantly, this effect is abolished by co-treatment with metformin, thus providing a potential treatment option for rapalogue-evoked pain. Our findings highlight the physiological relevance of feedback signaling through mTORC1 inhibition and have important implications for development of pain therapeutics that target the mTOR pathway.

Topics: Animals; Down-Regulation; Enzyme Activation; Feedback, Physiological; Insulin Receptor Substrate Proteins; Male; MAP Kinase Signaling System; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Inbred C57BL; Mice, Inbred ICR; Multiprotein Complexes; Pain; Rats; Rats, Sprague-Dawley; Sensory Receptor Cells; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) is a key regulator of mRNA translation whose action can be inhibited by the drug rapamycin. Forms of long-term plasticity require protein synthesis and evidence indicates that mRNA in dendrites, axon terminals and cell bodies is essential for long-term synaptic plasticity. Specific to pain, shifts in pain thresholds and responsiveness are an expression of neuronal plasticity and this likely contributes to persistent pain. We investigated this by inhibiting the activity of mTOR with rapamycin at the spinal level, of rats that were subjected to the formalin test, using both behavioural and electrophysiological techniques.. For in vivo electrophysiology, Sprague Dawley rats were fully anaesthetised and single-unit extracellular recordings were obtained from lamina V wide dynamic range (WDR) dorsal horn spinal neurones at the region where input is received from the hind paw. Neuronal responses from naive rats showed that rapamycin-sensitive pathways were important in nociceptive-specific C-fibre mediated transmission onto WDR neurones as well mechanically-evoked responses since rapamycin was effective in attenuating these measures. Formalin solution was injected into the hind paw prior to which, rapamycin or vehicle was applied directly onto the exposed spinal cord. When rapamycin was applied to the spinal cord prior to hind paw formalin injection, there was a significant attenuation of the prolonged second phase of the formalin test, which comprises continuing afferent input to the spinal cord, neuronal hyperexcitability and an activated descending facilitatory drive from the brainstem acting on spinal neurones. In accordance with electrophysiological data, behavioural studies showed that rapamycin attenuated behavioural hypersensitivity elicited by formalin injection into the hind paw.. We conclude that mTOR has a role in maintaining persistent pain states via mRNA translation and thus protein synthesis. We hypothesise that mTOR may be activated by excitatory neurotransmitter release acting on sensory afferent terminals as well as dorsal horn spinal neurones, which may be further amplified by descending facilitatory systems originating from higher centres in the brain.

Topics: Animals; Behavior, Animal; Electrophysiology; Formaldehyde; Male; Neuronal Plasticity; Pain; Protein Biosynthesis; Protein Kinases; Rats; Rats, Sprague-Dawley; RNA, Messenger; Sirolimus; Spinal Cord; Synaptic Transmission; TOR Serine-Threonine Kinases

The macrolide sirolimus (rapamycin) selectively blocks translation of mRNAs containing a terminal 5' oligopyrimidine (TOP) tract by altering the activity of mammalian target of rapamycin (mTOR) and inhibiting downstream mTOR pathway components involved in TOP mRNA translation. The skin disorder pachyonychia congenita (PC) is caused by mutations in the inducible keratins (K) including K6a, K6b, K16 and K17. Published sequence data suggest the 5' untranslated regions of K6a and K6b mRNAs contain 5' TOP motifs and therefore may be sensitive to rapamycin treatment.. Determine if mTOR inhibitors (rapamycin, temsirolimus or everolimus) are viable drug candidates for treatment of PC and other disorders caused by inappropriate expression of K6a and K6b.. 5' RACE analysis was used to map the transcriptional start sites for K5, K6a, K6b, K14, K16 and K17. The sensitivity of these keratins to mTOR inhibitors was determined by Western and qPCR analysis following treatment of a human HaCaT keratinocyte cell line with rapamycin, temsirolimus or everolimus. A small off-label study was undertaken using orally administered rapamycin in three PC patients and the effects were monitored by clinical examination, photography, a validated Dermatology Life Quality Index (DLQI) and a pain and activity diary.. Sequence comparison and 5' RACE analysis of the 5' untranslated regions of K6a and K6b revealed putative TOP regulatory elements. Treatment of a human HaCaT keratinocyte cell line with mTOR inhibitors (rapamycin, temsirolimus or everolimus) resulted in selective K6a repression. Furthermore, treatment of this HaCaT cell line with siRNAs targeting components of the mTOR pathway altered the levels of K6a expression. To test the ability of rapamycin to ameliorate PC symptoms, an off-label study was conducted. PC patient clinical responses to oral rapamycin showed a therapeutic response in callus character as well as subjective improvement. Of particular note, rapamycin greatly reduced the presence of painful cutaneous thromboses after reaching therapeutic serum levels. The well-known rapamycin side effects led to the early withdrawal of all of the patients from the study.. Rapamycin selectively blocks K6a expression in human keratinocytes. The improvement of symptoms in PC patients following rapamycin treatment suggests rapamycin (or rapamycin analogs) may be a therapeutic option, particularly if topical formulations can be developed that avoid the side effects associated with systemic administration.

Topics: 5' Untranslated Regions; Administration, Oral; Base Sequence; Cell Line; Dose-Response Relationship, Drug; Everolimus; Female; Gene Expression Regulation; Humans; Keratin-6; Keratinocytes; Molecular Sequence Data; Pachyonychia Congenita; Pain; Pain Measurement; Protein Kinases; Quality of Life; RNA 5' Terminal Oligopyrimidine Sequence; RNA Interference; RNA, Messenger; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Transcription Initiation Site; Transcription, Genetic; Treatment Outcome

Translational control through the mammalian target of rapamycin (mTOR) is critical for synaptic plasticity, cell growth, and axon guidance. Recently, it was also shown that mTOR signaling was essential for the maintenance of the sensitivity of subsets of adult sensory neurons. Here, we show that persistent pain states, but not acute pain behavior, are substantially alleviated by centrally administered rapamycin, an inhibitor of the mTOR pathway. We demonstrate that rapamycin modulates nociception by acting on subsets of primary afferents and superficial dorsal horn neurons to reduce both primary afferent sensitivity and central plasticity. We found that the active form of mTOR is present in a subpopulation of myelinated dorsal root axons, but rarely in unmyelinated C-fibers, and heavily expressed in the dorsal horn by lamina I/III projection neurons that are known to mediate the induction and maintenance of pain states. Intrathecal injections of rapamycin inhibited the activation of downstream targets of mTOR in dorsal horn and dorsal roots and reduced the thermal sensitivity of A-fibers. Moreover, in vitro studies showed that rapamycin increased the electrical activation threshold of Adelta-fibers in dorsal roots. Together, our results imply that central rapamycin reduces neuropathic pain by acting both on an mTOR-positive subset of A-nociceptors and lamina I projection neurons and suggest a new pharmacological route for therapeutic intervention in persistent pain states.

Topics: Afferent Pathways; Animals; Hyperalgesia; Immunosuppressive Agents; Male; Nerve Fibers, Myelinated; Nociceptors; Pain; Pain Measurement; Pain Threshold; Peripheral Nervous System Diseases; Posterior Horn Cells; Protein Kinases; Rats; Rats, Sprague-Dawley; Rats, Wistar; Sciatic Neuropathy; Sirolimus; Spinal Nerve Roots; Spinothalamic Tracts; TOR Serine-Threonine Kinases

The reflex sympathetic dystrophy syndrome (RSDS) in organ transplant recipients has only previously been reported in patients treated with calcineurin inhibitors. We retrospectively analyzed 393 renal transplant patients treated with sirolimus, 9 of whom developed RSDS. All the patients reported varying degrees of pain in the legs, affecting the knees, ankles, and/or feet, plus cutaneous erythema. The onset of pain ranged from 1-6 months after transplantation. At the time of diagnosis of RSDS, the mean serum creatinine was 1.4 mg/dL (range 1.0-1.7) and bone scintigraphy with 99mTc pyrophosphate showed increased uptake in all cases. The symptoms remitted 3-10 months after treatment (mean, 4 months) with calcitriol, with or without nifedipine or calcitonin, and in one case with suppression of sirolimus. We conclude that sirolimus therapy may induce RSDS in renal transplant recipients.

Topics: Adult; Female; Humans; Immunosuppressive Agents; Kidney Transplantation; Male; Middle Aged; Pain; Pain Measurement; Reflex Sympathetic Dystrophy; Retrospective Studies; Sirolimus

Topics: Adult; Bone and Bones; Calcineurin Inhibitors; Cyclosporins; Everolimus; Follow-Up Studies; Humans; Immunosuppressive Agents; Kidney Transplantation; Magnetic Resonance Imaging; Male; Middle Aged; Osteoporosis; Pain; Postoperative Period; Radiography; Radionuclide Imaging; Sirolimus; Syndrome; Tacrolimus; Time Factors