sirolimus and Weight-Loss

With the advent of targeted agents for the treatment of renal cell carcinoma (RCC), overall survival has improved, and patients are being treated continuously for increasingly long periods of time. This has raised challenges in the management of adverse events (AEs) associated with the six targeted agents approved in RCC-sorafenib, sunitinib, pazopanib, bevacizumab (in combination with interferon alpha), temsirolimus, and everolimus. Suggestions for monitoring and managing AEs have been published, but there are few consensus recommendations. In addition, there is a risk that patients will be subjected to multiple unnecessary investigations. In this review, we aimed to identify the level of supporting evidence for suggested AE management strategies to provide practical guidance on essential monitoring and management that should be undertaken when using targeted agents. Five databases were systematically searched for relevant English language articles (including American Society of Clinical Oncology abstracts) published between January 2007 and March 2011; European Society of Medical Oncology congress abstracts were hand searched. Strategies for AE management were summarized and categorized according to the level of recommendation. A total of 107 articles were identified that describe a large number of different investigations for monitoring AEs and interventions for AE management. We identify and summarize clear recommendations for the management of dermatologic, gastrointestinal, thyroid, cardiovascular, and other AEs, based predominantly on expert opinion. However, because the evidence for the suggested management strategies is largely anecdotal, there is a need for further systematic investigation of management strategies for AEs related to targeted therapies for RCC.

Topics: Anorexia; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Benzenesulfonates; Bevacizumab; Carcinoma, Renal Cell; Cardiovascular System; Drug Eruptions; Europe; Everolimus; Evidence-Based Medicine; Gastrointestinal Tract; Humans; Hypothyroidism; Indazoles; Indoles; Kidney Neoplasms; Molecular Targeted Therapy; Niacinamide; Phenylurea Compounds; Pneumonia; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Pyridines; Pyrimidines; Pyrroles; Sirolimus; Sorafenib; Sulfonamides; Sunitinib; TOR Serine-Threonine Kinases; Vascular Endothelial Growth Factor A; Weight Loss; Wound Healing

The protein leverage hypothesis predicts that low dietary protein should increase energy intake and cause adiposity. We designed 10 diets varying from 1% to 20% protein combined with either 60% or 20% fat. Contrasting the expectation, very low protein did not cause increased food intake. Although these mice had activated hunger signaling, they ate less food, resulting in decreased body weight and improved glucose tolerance but not increased frailty, even under 60% fat. Moreover, they did not show hyperphagia when returned to a 20% protein diet, which could be mimicked by treatment with rapamycin. Intracerebroventricular injection of AAV-S6K1 significantly blunted the decrease in both food intake and body weight in mice fed 1% protein, an effect not observed with inhibition of eIF2a, TRPML1, and Fgf21 signaling. Hence, the 1% protein diet induced decreased food intake and body weight via a mechanism partially dependent on hypothalamic mTOR signaling.

Topics: Activating Transcription Factor 4; Adipose Tissue, White; Animals; Diet, Protein-Restricted; Eating; Energy Metabolism; Fibroblast Growth Factors; Gene Expression; Glucose Tolerance Test; Hyperphagia; Hypothalamus; Leptin; Liver; Male; Mice; Mice, Inbred C57BL; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Weight Loss

Alcohol Use Disorder (AUD) affects a large portion of the population. Unfortunately, efficacious medications to treat the disease are limited. Studies in rodents suggest that mTORC1 plays a crucial role in mechanisms underlying phenotypes such as heavy alcohol intake, habit, and relapse. Thus, mTORC1 inhibitors, which are used in the clinic, are promising therapeutic agents to treat AUD. However, chronic inhibition of mTORC1 in the periphery produces undesirable side effects, which limit their potential use for the treatment of AUD. To overcome these limitations, we designed a binary drug strategy in which male mice were treated with the mTORC1 inhibitor RapaLink-1 together with a small molecule (RapaBlock) to protect mTORC1 activity in the periphery. We show that whereas RapaLink-1 administration blocked mTORC1 activation in the liver, RapaBlock abolished the inhibitory action of Rapalink-1. RapaBlock also prevented the adverse side effects produced by chronic inhibition of mTORC1. Importantly, co-administration of RapaLink-1 and RapaBlock inhibited alcohol-dependent mTORC1 activation in the nucleus accumbens and attenuated alcohol seeking and drinking.

Topics: Alcohol Drinking; Animals; Brain; Glucose Intolerance; Liver; Male; Mechanistic Target of Rapamycin Complex 1; Mice, Inbred C57BL; Nucleus Accumbens; Organ Specificity; Sirolimus; Weight Loss

Autonomic dysreflexia (AD) is a potentially life-threatening syndrome in individuals with spinal cord injury (SCI) above the T6 spinal level that is characterized by episodic hypertension in response to noxious stimuli below the lesion. Maladaptive intraspinal plasticity is thought to contribute to the temporal development of AD, and experimental approaches that reduce such plasticity mitigate the severity of AD. The mammalian target of rapamycin (mTOR) has gained interest as a mediator of plasticity, regeneration, and nociceptor hypersensitivity in the injured spinal cord. Based on our preliminary data that prolonged rapamycin (RAP) treatment markedly reduces mTOR activity in the cord weeks after high-thoracic (T4) spinal transection, we sought to determine whether RAP could modulate AD development by impeding intraspinal plasticity. Naïve and injured rats were administered RAP or vehicle every other day, beginning immediately after injury for four weeks, and hemodynamic monitoring was conducted to analyze the frequency of spontaneously occurring AD, as well as the severity of colorectal distention (CRD) induced AD. Results showed that after SCI, RAP significantly exacerbated sustained body weight loss and caused a marked elevation in resting blood pressure, with average daily blood pressure rising above even normal naïve levels within one week after injury. Moreover, RAP significantly increased the frequency of daily spontaneous AD and increased the absolute blood pressure induced by CRD at three weeks post-injury. These dynamic cardiovascular effects were not, however, correlated with changes in the density of nociceptive c-fibers or c-Fos+ neurons throughout the spinal cord, indicating that intraspinal plasticity associated with AD was not altered by treatment. These findings caution against the use of RAP as a therapeutic intervention for SCI because it evokes toxic weight loss and exacerbates cardiovascular dysfunction perhaps mediated by increased peripheral nociceptor sensitivity and/or vascular resistance.

Topics: Animals; Autonomic Dysreflexia; Blood Pressure; Female; Immunosuppressive Agents; Male; Neuronal Plasticity; Rats; Sirolimus; Spinal Cord Injuries; Thoracic Vertebrae; Weight Loss

Previous studies reported that autophagy is activated in human dilated cardiomyopathy (DCM). It is still unknown whether modulating autophagy can improve cardiac function of the failing heart.. We immunized rats with porcine cardiac myosin to set up a model of DCM. Rapamycin, a kind of mTOR inhibitor upregulating autophagy, was given to rats weeks after the immunization at low (1 mg/kg · day i.p.), intermediate (2 mg/kg · day i.p.) and high dose (4 mg/kg · day i.p.) for 2 weeks.. Compared to the control group (ejection fraction, EF = 81.3 ± 3.8%), the average EF decreased in both the DCM group (EF = 56.1 ± 3.3%) and the high-dose rapamycin group (EF = 55.9 ± 3.6%), but recovered in the low-/intermediate-dose rapamycin groups (EF = 64.9 ± 4.6/69.4 ± 4.4%). Phosphorylation of p70s6k and 4E-BP1 decreased and the expression of LC3BI/II increased in all rapamycin groups. Autophagic vacuoles were easily found in these groups. However, body weight was significantly reduced in the rapamycin groups. Furthermore, mortality was increased in the high-dose rapamycin group.. Rapamycin could improve cardiac function of early-stage DCM, but the effect of rapamycin turned out to be biphasic and the effective range appeared narrow.

Topics: Analysis of Variance; Animals; Autoimmune Diseases; Autophagy; Cardiomyopathy, Dilated; Cardiotonic Agents; Disease Models, Animal; Dose-Response Relationship, Drug; Male; Rats; Rats, Inbred Lew; Sirolimus; Stroke Volume; TOR Serine-Threonine Kinases; Weight Loss

The prevalence of obesity, an established risk and progression factor for postmenopausal breast cancer, remains high in US women. Activation of Akt/mammalian target of rapamycin (mTOR) signaling plays a key role in the obesity-breast cancer link. However, the impact of weight normalization in obese postmenopausal women on breast tumorigenesis and/or Akt/mTOR activation is poorly characterized. To model this, ovariectomized female C57BL/6 mice were fed a control diet (n = 20), a calorie restriction (CR) regimen (n = 20), or a diet-induced obesity (DIO) diet (n = 30). At week 17, DIO mice were switched to control diet, resulting in formerly obese (FOb) mice with weights identical to the controls by week 20. MMTV-Wnt-1 mammary tumor cells were injected at 20 wk into each mouse. Two weeks post-injection, vehicle or the mTOR inhibitor RAD001 at 10 or 15 mg/kg body weight (n = 10/diet group) was administered by gavage twice/week until termination. Relative to controls, CR mice had decreased (and DIO mice had increased) serum insulin-like growth factor-1 (IGF-1) and phosphorylation of Akt/mTOR pathway components. RAD001 decreased tumor growth in the CR, control, and FOb mice. Wnt-1 tumor cells treated in vitro with serum from mice from each group established that diet-dependent circulating factors contribute to tumor growth and invasiveness. These findings suggest weight normalization in obese mice does not immediately reverse tumor progression or Akt/mTOR activation. Treatment with RAD001 blocked mammary tumor development and mTOR activation observed in the FOb mice, suggesting combination of lifestyle and pharmacologic strategies may be effective for breaking the obesity-breast cancer link.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Diet; Everolimus; Female; Hormones; Insulin-Like Growth Factor I; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Mice; Mice, Inbred C57BL; Mice, Obese; Obesity; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Weight Loss; Wnt1 Protein

mTOR inhibitors are currently used as immunosuppressants in transplanted patients and as promising anti-cancer agents. However, new-onset diabetes is a frequent complication occurring in patients treated with mTOR inhibitors such as rapamycin (Sirolimus). Here, we investigated the mechanisms associated with the diabetogenic effects of chronic Sirolimus administration in rats and in in vitro cell cultures.. Sirolimus was administered to rats fed either a standard or high-fat diet for 21 days. Metabolic parameters were measured in vivo and in ex vivo tissues. Insulin sensitivity was assessed by glucose tolerance tests and euglycaemic hyperinsulinaemic clamps. Rapamycin effects on glucose metabolism and insulin signalling were further evaluated in cultured myotubes.. Sirolimus induced a decrease in food intake and concomitant weight loss. It also induced specific fat mass loss that was independent of changes in food intake. Despite these beneficial effects, Sirolimus-treated rats were glucose intolerant, hyperinsulinaemic and hyperglycaemic, but not hyperlipidaemic. The euglycaemic hyperinsulinaemic clamp measurements showed skeletal muscle is a major site of Sirolimus-induced insulin resistance. At the molecular level, long-term Sirolimus administration attenuated glucose uptake and metabolism in skeletal muscle by preventing full insulin-induced Akt activation and altering the expression and translocation of glucose transporters to the plasma membrane. In rats fed a high-fat diet, these metabolic defects were exacerbated, although Sirolimus-treated animals were protected from diet-induced obesity.. Taken together, our data demonstrate that the diabetogenic effect of chronic rapamycin administration is due to an impaired insulin action on glucose metabolism in skeletal muscles.

Topics: Adipose Tissue; Animals; Cells, Cultured; Diet, High-Fat; Fatty Liver; Glucose; Glucose Clamp Technique; Glucose Intolerance; Glucose Transporter Type 4; Immunosuppressive Agents; Insulin; Insulin Resistance; Male; Muscle Fibers, Skeletal; Muscle, Skeletal; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Weight Loss

Hyperthyroidism is characterized in rats by increased energy expenditure and marked hyperphagia. Alterations of thermogenesis linked to hyperthyroidism are associated with dysregulation of hypothalamic AMPK and fatty acid metabolism; however, the central mechanisms mediating hyperthyroidism-induced hyperphagia remain largely unclear. Here, we demonstrate that hyperthyroid rats exhibit marked up-regulation of the hypothalamic mammalian target of rapamycin (mTOR) signalling pathway associated with increased mRNA levels of agouti-related protein (AgRP) and neuropeptide Y (NPY), and decreased mRNA levels of pro-opiomelanocortin (POMC) in the arcuate nucleus of the hypothalamus (ARC), an area where mTOR co-localizes with thyroid hormone receptor-α (TRα). Central administration of thyroid hormone (T3) or genetic activation of thyroid hormone signalling in the ARC recapitulated hyperthyroidism effects on feeding and the mTOR pathway. In turn, central inhibition of mTOR signalling with rapamycin in hyperthyroid rats reversed hyperphagia and normalized the expression of ARC-derived neuropeptides, resulting in substantial body weight loss. The data indicate that in the hyperthyroid state, increased feeding is associated with thyroid hormone-induced up-regulation of mTOR signalling. Furthermore, our findings that different neuronal modulations influence food intake and energy expenditure in hyperthyroidism pave the way for a more rational design of specific and selective therapeutic compounds aimed at reversing the metabolic consequences of this disease.

Topics: Agouti-Related Protein; AMP-Activated Protein Kinases; Animals; Disease Models, Animal; Eating; Feeding Behavior; Hyperphagia; Hyperthyroidism; Hypothalamus; Male; Neural Pathways; Neuropeptide Y; Phosphorylation; Pro-Opiomelanocortin; Protein Kinase Inhibitors; Rats; Rats, Sprague-Dawley; RNA, Messenger; Signal Transduction; Sirolimus; Thyroid Hormone Receptors alpha; Time Factors; TOR Serine-Threonine Kinases; Triiodothyronine; Weight Loss

Pain induced by calcineurin inhibitors is a rare complication of unknown pathogenesis. We have reported herein a 7-year-old child who presented with abdominal pain, vomiting, and weight loss showing no significant findings after an extensive laboratory and imaging workup. After conversion from tacrolimus to sirolimus, there was complete resolution of the gastrointestinal symptoms and pain; the patient displays excellent renal function. Calcineurin inhibitor-induced pain syndrome is diagnosis of exclusion but must be considered because the withdrawal of this immunosuppressive agent is associated with improvement in symptoms and quality of life.

Topics: Abdominal Pain; Calcineurin Inhibitors; Child; Drug Substitution; Female; Humans; Immunosuppressive Agents; Kidney Transplantation; Sirolimus; Tacrolimus; Treatment Outcome; Vomiting; Weight Loss

The adenomatous polyposis coli (APC) gene is mutated in familial adenomatous polyposis. Mice with a heterozygous APC(Min) mutation develop multiple intestinal neoplasia (Min) leading to premature death. Early in colorectal carcinogenesis, APC(Min/+) mice show enhanced Akt-mammalian target of rapamycin (mTOR) signaling, which is paralleled by upregulation of oncogenic K(+) channels. In this study, we tested the effect of mTOR inhibition with rapamycin on tumor formation in APC(Min/+) mice and evaluated ion channel regulation. We found that continuous long-term rapamycin treatment of APC(Min/+) mice dramatically inhibits intestinal neoplasia. Moreover, although untreated APC(Min/+) mice lose weight, experience intestinal bleeding and succumb to multiple neoplasia by 22.3+/-1.4 weeks of age, mice treated with rapamycin maintain stable weight and survive long term (39.6+/-3.4 weeks), with more than 30% surviving >1 year. Impressively, abnormalities in colonic electrolyte transport typical for APC(Min/+) mice are abolished, along with the suppression of epithelial Na(+) channel (ENaC) and oncogenic K(+) ion channels BK, Elk1 and Erg1, both functionally and at mRNA levels. These results show that continuous prophylaxis by rapamycin markedly inhibits the development of APC mutation-related polyposis, and suggest a novel contributing mechanism of action through the blockade of intestinal oncogenic ion channels.

Topics: Adenomatous Polyposis Coli Protein; Animals; Codon, Nonsense; Immunosuppressive Agents; Intestinal Mucosa; Intestinal Neoplasms; Intestinal Polyps; Intestines; Intracellular Signaling Peptides and Proteins; Ion Channels; Mice; Protein Serine-Threonine Kinases; Sirolimus; TOR Serine-Threonine Kinases; Weight Loss

The mammalian Target of Rapamycin (mTOR) protein is a serine-threonine kinase that regulates cell-cycle progression and growth by sensing changes in energy status. We demonstrated that mTOR signaling plays a role in the brain mechanisms that respond to nutrient availability, regulating energy balance. In the rat, mTOR signaling is controlled by energy status in specific regions of the hypothalamus and colocalizes with neuropeptide Y and proopiomelanocortin neurons in the arcuate nucleus. Central administration of leucine increases hypothalamic mTOR signaling and decreases food intake and body weight. The hormone leptin increases hypothalamic mTOR activity, and the inhibition of mTOR signaling blunts leptin's anorectic effect. Thus, mTOR is a cellular fuel sensor whose hypothalamic activity is directly tied to the regulation of energy intake.

Topics: Animals; Arcuate Nucleus of Hypothalamus; Eating; Energy Intake; Energy Metabolism; Fasting; Hypothalamus; Injections, Intraventricular; Leptin; Leucine; Neurons; Neuropeptide Y; Phosphorylation; Protein Kinases; Rats; Rats, Long-Evans; Ribosomal Protein S6; Ribosomal Protein S6 Kinases; Signal Transduction; Sirolimus; STAT3 Transcription Factor; TOR Serine-Threonine Kinases; Valine; Weight Loss

Topics: Animals; Autoimmune Diseases; Cyclosporine; Drug Evaluation, Preclinical; Female; Glomerulonephritis; Immunosuppressive Agents; Mercuric Chloride; Polyenes; Proteinuria; Rats; Rats, Inbred BN; Sirolimus; Splenomegaly; Weight Loss