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1.
Diabetes ; 70(9): 2081-2091, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34183373

RESUMO

Work in recent decades has established that metabolic hormones released by endocrine cells and diverse other cell types serve to regulate nutrient intake and energy homeostasis. Tsukushi (TSK) is a leucine-rich repeat-containing protein secreted primarily by the liver that exerts an inhibitory effect on brown fat sympathetic innervation and thermogenesis. Despite this, physiological regulation of TSK and the mechanisms underlying its effects on energy balance remain poorly understood. Here we show that hepatic expression and plasma concentrations of TSK are induced by feeding and regulated by melanocortin-4 receptor (MC4R) signaling. We generated TSK and MC4R-double-knockout mice to elucidate the nature of cross talk between TSK and the central regulatory circuit of energy balance. Remarkably, TSK inactivation restores energy balance, ameliorates hyperphagia, and improves metabolic health in MC4R-deficient mice. TSK ablation enhances thermogenic gene expression in brown fat, dampens obesity-association inflammation in the liver and adipose tissue, and protects MC4R-null mice from diet-induced nonalcoholic steatohepatitis. At the cellular level, TSK deficiency augments feeding-induced c-Fos expression in the paraventricular nucleus of the hypothalamus. These results illustrate physiological cross talk between TSK and the central regulatory circuit in maintaining energy balance and metabolic homeostasis.


Assuntos
Metabolismo Energético/fisiologia , Obesidade/metabolismo , Proteoglicanas/metabolismo , Receptor Tipo 4 de Melanocortina/metabolismo , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Animais , Fármacos Antiobesidade/farmacologia , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Camundongos , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/metabolismo , Obesidade/genética , Proteoglicanas/genética , Receptor Tipo 4 de Melanocortina/genética , Transdução de Sinais/fisiologia , Termogênese/fisiologia , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia
2.
J Exp Med ; 218(7)2021 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-33978701

RESUMO

Atypical antipsychotics such as risperidone cause drug-induced metabolic syndrome. However, the underlying mechanisms remain largely unknown. Here, we report a new mouse model that reliably reproduces risperidone-induced weight gain, adiposity, and glucose intolerance. We found that risperidone treatment acutely altered energy balance in C57BL/6 mice and that hyperphagia accounted for most of the weight gain. Transcriptomic analyses in the hypothalamus of risperidone-fed mice revealed that risperidone treatment reduced the expression of Mc4r. Furthermore, Mc4r in Sim1 neurons was necessary for risperidone-induced hyperphagia and weight gain. Moreover, we found that the same pathway underlies the obesogenic effect of olanzapine-another commonly prescribed antipsychotic drug. Remarkably, whole-cell patch-clamp recording demonstrated that risperidone acutely inhibited the activity of hypothalamic Mc4r neurons via the opening of a postsynaptic potassium conductance. Finally, we showed that treatment with setmelanotide, an MC4R-specific agonist, mitigated hyperphagia and obesity in both risperidone- and olanzapine-fed mice.


Assuntos
Antipsicóticos/farmacologia , Receptor Tipo 4 de Melanocortina/metabolismo , Risperidona/farmacologia , Aumento de Peso/efeitos dos fármacos , Animais , Feminino , Hiperfagia/metabolismo , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Masculino , Síndrome Metabólica/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Modelos Animais , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Obesidade/metabolismo , Olanzapina/farmacologia , Potássio/metabolismo , Potenciais Sinápticos/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia
3.
Clin Exp Dermatol ; 46(7): 1189-1204, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33872410

RESUMO

Systemic photoprotection aims to negate the negative effects of ultraviolet radiation-induced DNA damage. Systemic supplements may be used as a monotherapy or in combination with topical sunscreens. Using the keywords 'carotenoids', 'flavonoids', 'systemic photoprotection', 'polyphenols' and 'polypodium leucotomos extract', we searched the databases MEDLINE and EMBASE to find relevant English-language articles. Few trials have supported the use of any of these supplements as monotherapy, impeding the recommendation of these systemic supplements as an alternative to sunscreen for photoprotection. Nicotinamide has exhibited clinically relevant benefits in reducing nonmelanoma skin cancers in trials and could be recommended as an adjunctive therapy for the most vulnerable indviduals. Further research is required, which needs to be of higher statistical power, using more clinically meaningful outcome measures with comparison to the current gold standard of care (topical photoprotection) to support the use of alternative therapies in clinical practice.


Assuntos
Suplementos Nutricionais , Extratos Vegetais/uso terapêutico , Neoplasias Cutâneas/prevenção & controle , Protetores Solares , Antioxidantes/uso terapêutico , Carotenoides/uso terapêutico , Fármacos Dermatológicos/uso terapêutico , Flavonoides/uso terapêutico , Humanos , Raios Ultravioleta , alfa-MSH/análogos & derivados , alfa-MSH/uso terapêutico
4.
Clin Exp Dermatol ; 46(2): 248-258, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33350506

RESUMO

Vitiligo is an autoimmune skin condition characterized by depigmented macules and patches, and has a huge psychosocial impact on patients. Treatment of vitiligo aims to prevent the spread of disease and facilitate repigmentation of affected lesions. The mainstay of treatment for unstable vitiligo has been topical agents (corticosteroids, calcineurin inhibitors) and phototherapy. However, systemic treatments are increasingly being shown to have a significant impact on the course of the disease as monotherapy or adjunctive therapy. Of note, oral mini-pulsed corticosteroid therapy, methotrexate, minocycline, ciclosporin, Janus kinase inhibitors and certain supplements have been used in the systemic treatment of vitiligo. We review the underlying evidence supporting the use of each of these systemic treatments.


Assuntos
Corticosteroides/uso terapêutico , Inibidores de Calcineurina/uso terapêutico , Terapia Neoadjuvante/métodos , Fototerapia/métodos , Vitiligo/patologia , Vitiligo/terapia , Administração Oral , Administração Tópica , Corticosteroides/administração & dosagem , Corticosteroides/efeitos adversos , Antibacterianos/administração & dosagem , Antibacterianos/efeitos adversos , Antibacterianos/uso terapêutico , Inibidores de Calcineurina/administração & dosagem , Inibidores de Calcineurina/efeitos adversos , Terapia Combinada , Ciclosporina/administração & dosagem , Ciclosporina/efeitos adversos , Ciclosporina/uso terapêutico , Fármacos Dermatológicos/administração & dosagem , Fármacos Dermatológicos/efeitos adversos , Fármacos Dermatológicos/uso terapêutico , Humanos , Inibidores de Janus Quinases/administração & dosagem , Inibidores de Janus Quinases/efeitos adversos , Inibidores de Janus Quinases/uso terapêutico , Metotrexato/administração & dosagem , Metotrexato/efeitos adversos , Metotrexato/uso terapêutico , Minociclina/administração & dosagem , Minociclina/efeitos adversos , Minociclina/uso terapêutico , Avaliação de Resultados em Cuidados de Saúde , Fototerapia/efeitos adversos , Psicologia , Vitiligo/psicologia , alfa-MSH/administração & dosagem , alfa-MSH/efeitos adversos , alfa-MSH/análogos & derivados , alfa-MSH/uso terapêutico
5.
Neurosci Lett ; 738: 135335, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-32891671

RESUMO

Proopiomelanocortin (POMC) is a neuropeptide precursor produced in the anterior and intermediate pituitary lobes, the hypothalamic arcuate nucleus (ARC), and solitary tract nucleus. Alpha-melanocyte-stimulating hormone (α-MSH) is a cell type specific POMC derivative that is essential for regulating feeding, and energy homeostasis. However, the molecular mechanism underlying POMC/α-MSH secretion remains unclear. Ca2+-dependent activator protein for secretion 2 (CAPS2) is a regulatory protein involved in the exocytosis of dense-core vesicles containing neuropeptides. We previously reported CAPS2 localization in the intermediate pituitary lobe and reduced body weights in Caps2-knockout (Caps2-KO) mice, compared to control mice. Here, we aimed to investigate CAPS2 expression in POMC-expressing neurons and the effects of CAPS2 deficiency on the secretion of POMC-related peptides and feeding behavior phenotype. CAPS2 was localized in the POMC-expressing neurons of the intermediate pituitary lobe, hypothalamic ARC, and the paraventricular nucleus, which is innervated by hypothalamic neurons. POMC protein levels in the intermediate pituitary lobe of Caps2-KO mice were significantly higher than that in the control mice, suggesting a possible accumulation of POMC-derived peptides in the intermediate pituitary lobe of Caps2-KO mice. Moreover, administration of low-dose melanotan-2, an α-MSH receptor (MC4R) agonist, decreased food intake per body weight in Caps2-KO mice; no such effect was observed in the wildtype mice. Collectively, these results suggest that CAPS2 is involved in regulating the secretion of POMC-derived peptides, including α-MSH, is partially associated with feeding, and affects energy metabolism.


Assuntos
Proteínas de Ligação ao Cálcio/genética , Ingestão de Alimentos/genética , Hipotálamo/metabolismo , Proteínas do Tecido Nervoso/genética , Hipófise/metabolismo , Pró-Opiomelanocortina/metabolismo , Animais , Peso Corporal/efeitos dos fármacos , Peso Corporal/genética , Proteínas de Ligação ao Cálcio/metabolismo , Ingestão de Alimentos/efeitos dos fármacos , Hipotálamo/efeitos dos fármacos , Masculino , Camundongos , Camundongos Knockout , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Peptídeos Cíclicos/farmacologia , Hipófise/efeitos dos fármacos , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia
7.
Dermatol Clin ; 37(2): 175-181, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30850040

RESUMO

Pigmentary disorders are common and can be very distressing to patients. There is a need for better, standardized therapies. The authors review the most recent data for topical, systemic, light, and laser treatments for vitiligo, melasma, and postinflammatory hyperpigmentation. There is a paucity of large-scale, well-designed, randomized, controlled trials for these treatments. Treatment options are often drawn from smaller trials and case series. The treatments described in this article are promising candidates for larger follow-up studies.


Assuntos
Fármacos Dermatológicos/uso terapêutico , Inibidores de Janus Quinases/uso terapêutico , Transtornos da Pigmentação/terapia , Antifibrinolíticos/uso terapêutico , Bimatoprost/uso terapêutico , Humanos , Hidroquinonas/uso terapêutico , Inflamação , Queratinócitos/transplante , Lasers de Estado Sólido/uso terapêutico , Terapia com Luz de Baixa Intensidade , Melanócitos/transplante , Melanose , Preparações Clareadoras de Pele/uso terapêutico , Protetores Solares/uso terapêutico , Ácido Tranexâmico/uso terapêutico , Vitiligo/terapia , alfa-MSH/análogos & derivados , alfa-MSH/uso terapêutico
8.
Hautarzt ; 68(11): 876-884, 2017 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-29030646

RESUMO

Systemic drug treatment of vitiligo is currently limited to predominantly adjuvant measures for increasing the effectiveness of UV light therapy. We here present new approaches for the systemic treatment of vitiligo currently under clinical investigation. These include the α­MSH-analogue afamelatonide and oral immunosuppressants such as the Janus kinase (JAK) inhibitors which target interferon-α-dependent autotoxic inflammatory reactions. In 2015 the first publications on the successful systemic use of Janus kinase (JAK) inhibitors in vitiligo appeared. The effectiveness was experimentally supported by animal models of vitiligo and by the characterization of new biomarkers in the serum of vitiligo patients. This may significantly expand the range of treatment options for vitiligo. Topical antiinflammatory and UV therapies are still the main components of vitiligo treatment, often in combination. The main outcome parameters include the extent and duration of repigmentation, cessation of spreading, avoidance of side effects and improvement in the quality of life of patients.


Assuntos
Imunossupressores/uso terapêutico , Janus Quinases/antagonistas & inibidores , Piperidinas/uso terapêutico , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Pirróis/uso terapêutico , Terapia Ultravioleta , Vitiligo/diagnóstico , Vitiligo/terapia , alfa-MSH/análogos & derivados , Animais , Biomarcadores/sangue , Terapia Combinada , Modelos Animais de Doenças , Humanos , Imunossupressores/efeitos adversos , Interferon-alfa/antagonistas & inibidores , Nitrilas , Piperidinas/efeitos adversos , Pirazóis/efeitos adversos , Pirimidinas/efeitos adversos , Pirróis/efeitos adversos , Terapia Ultravioleta/efeitos adversos , Vitiligo/fisiopatologia , alfa-MSH/efeitos adversos , alfa-MSH/uso terapêutico
9.
Dermatol Clin ; 35(2): 163-170, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28317526

RESUMO

Medical treatments alone, or in combination with phototherapy, are key approaches for treating nonsegmental vitiligo and, to a lesser extent, segmental vitiligo. The treatments are useful for halting disease progression and have been proven effective for inducing repigmentation and decreasing risk of relapses. Although the treatments have side effects and limitations, vitiligo often induces a marked decrease in quality of life and in most cases the risk:benefit ratio is in favor of an active approach. Systemic and topical agents targeting the pathways involved in loss of melanocytes and in differentiation of melanocyte stem cells should provide more effective approaches in the near future.


Assuntos
Corticosteroides/uso terapêutico , Antibacterianos/uso terapêutico , Inibidores de Calcineurina/uso terapêutico , Imunossupressores/uso terapêutico , Fototerapia , Vitiligo/terapia , Administração Cutânea , Dinoprostona/uso terapêutico , Humanos , Terapia com Luz de Baixa Intensidade , Metotrexato/uso terapêutico , Minociclina/uso terapêutico , Ocitócicos/uso terapêutico , Piperidinas/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Pirimidinas/uso terapêutico , Pirróis/uso terapêutico , Terapia Ultravioleta , Vitamina D/análogos & derivados , alfa-MSH/análogos & derivados , alfa-MSH/uso terapêutico
10.
J Comp Physiol B ; 187(4): 603-612, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28197776

RESUMO

Melanocortin-4 receptor (Mc4r) function related to reproduction in fish has not been extensively investigated. Here, we report on gene expression changes by real-time PCR following treatment with Mc4r agonists and antagonists in the spotted scat (Scatophagus argus). Using in vitro incubated hypothalamus, the Mc4r nonselective agonist NDP-MSH ([Nle4, D-Phe7]-α-melanocyte stimulating hormone; 10-6 M) and selective agonist THIQ (N-[(3R)-1, 2, 3, 4-Tetrahydroisoquinolinium-3-ylcarbonyl]- (1R)-1-(4-chlorobenzyl)-2-[4-cyclohexyl-4-(1H-1,2,4-triazol-1-ylmethyl) piperidin-1-yl]-2-oxoethylamine; 10-7 M) significantly increased the expression of gnrh (Gonadotropin releasing hormone), while the Mc4r nonselective antagonist SHU9119 (Ac-Nle-[Asp-His-DPhe/DNal(2')-Arg-Trp-Lys]-NH2; 10-6 M) and selective antagonist Ipsen 5i (compound 5i synthesized in Ipsen Research Laboratories; 10-6 M) significantly inhibited gnrh expression after 3 h of incubation. In incubated pituitary tissue, NDP-MSH and THIQ significantly increased the expression of fshb (Follicle-stimulating hormone beta subunit) and lhb (Luteinizing hormone beta subunit), while SHU9119 and Ipsen 5i significantly decreased fshb and lhb expression after 3 h of incubation. During the in vivo experiment, THIQ (1 mg/kg bw) significantly increased gnrh expression in hypothalamic tissue, as well as the fshb and lhb expression in pituitary tissue 12 h after abdominal injection. Furthermore, Ipsen 5i (1 mg/kg bw) significantly inhibited gnrh expression in hypothalamic tissue, as well as fshb and lhb gene expression in pituitary tissue 12 h after abdominal injection. In summary, Mc4r singling appears to stimulate gnrh expression in the hypothalamus, thereby modulating the synthesis of Fsh and Lh in the pituitary. In addition, Mc4r also appears to directly regulate fshb and lhb levels in the pituitary in spotted scat. Our study suggests that Mc4r, through the hypothalamus and pituitary, participates in reproductive regulation in fish.


Assuntos
Proteínas de Peixes/genética , Perciformes/fisiologia , Receptor Tipo 4 de Melanocortina/agonistas , Receptor Tipo 4 de Melanocortina/antagonistas & inibidores , Animais , Feminino , Subunidade beta do Hormônio Folículoestimulante/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Hormônio Liberador de Gonadotropina/genética , Hipotálamo/efeitos dos fármacos , Hormônio Luteinizante Subunidade beta/genética , Hormônios Estimuladores de Melanócitos/farmacologia , Técnicas de Cultura de Órgãos/métodos , Receptor Tipo 4 de Melanocortina/genética , Reprodução/efeitos dos fármacos , Reprodução/genética , Tetra-Hidroisoquinolinas/farmacologia , Triazóis/farmacologia , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia
11.
J Physiol ; 594(18): 5285-301, 2016 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-27126579

RESUMO

KEY POINTS: The ventromedial hypothalamus (VMH) and the central melanocortin system both play vital roles in regulating energy balance by modulating energy intake and utilization. Recent evidence suggests that activation of the VMH alters skeletal muscle metabolism. We show that intra-VMH melanocortin receptor activation increases energy expenditure and physical activity, switches fuel utilization to fats, and lowers work efficiency such that excess calories are dissipated by skeletal muscle as heat. We also show that intra-VMH melanocortin receptor activation increases sympathetic nervous system outflow to skeletal muscle. Intra-VMH melanocortin receptor activation also induced significant changes in the expression of mediators of energy expenditure in muscle. These results support the role of melanocortin receptors in the VMH in the modulation of skeletal muscle metabolism. ABSTRACT: The ventromedial hypothalamus (VMH) and the brain melanocortin system both play vital roles in increasing energy expenditure (EE) and physical activity, decreasing appetite and modulating sympathetic nervous system (SNS) outflow. Because of recent evidence showing that VMH activation modulates skeletal muscle metabolism, we propose the existence of an axis between the VMH and skeletal muscle, modulated by brain melanocortins, modelled on the brain control of brown adipose tissue. Activation of melanocortin receptors in the VMH of rats using a non-specific agonist melanotan II (MTII), compared to vehicle, increased oxygen consumption and EE and decreased the respiratory exchange ratio. Intra-VMH MTII enhanced activity-related EE even when activity levels were held constant. MTII treatment increased gastrocnemius muscle heat dissipation during controlled activity, as well as in the home cage. Compared to vehicle-treated rats, rats with intra-VMH melanocortin receptor activation had higher skeletal muscle norepinephrine turnover, indicating an increased SNS drive to muscle. Lastly, intra-VMH MTII induced mRNA expression of muscle energetic mediators, whereas short-term changes at the protein level were primarily limited to phosphorylation events. These results support the hypothesis that melanocortin peptides act in the VMH to increase EE by lowering the economy of activity via the enhanced expression of mediators of EE in the periphery including skeletal muscle. The data are consistent with the role of melanocortins in the VMH in the modulation of skeletal muscle metabolism.


Assuntos
Metabolismo Energético , Hipotálamo/fisiologia , Músculo Esquelético/fisiologia , Receptores de Melanocortina/fisiologia , Termogênese , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/fisiologia , Tecido Adiposo Branco/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Tecido Adiposo Branco/fisiologia , Animais , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/fisiologia , Masculino , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Norepinefrina/metabolismo , Peptídeos Cíclicos/farmacologia , Condicionamento Físico Animal , Ratos Sprague-Dawley , Receptores de Melanocortina/agonistas , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia
12.
Diabetes ; 65(3): 660-72, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26467632

RESUMO

Hypothalamic proopiomelanocortin (POMC) is essential for the physiological regulation of energy balance; however, its role in glucose homeostasis remains less clear. We show that hypothalamic arcuate nucleus (Arc)POMC-deficient mice, which develop severe obesity and insulin resistance, unexpectedly exhibit improved glucose tolerance and remain protected from hyperglycemia. To explain these paradoxical phenotypes, we hypothesized that an insulin-independent pathway is responsible for the enhanced glucose tolerance. Indeed, the mutant mice demonstrated increased glucose effectiveness and exaggerated glycosuria relative to wild-type littermate controls at comparable blood glucose concentrations. Central administration of the melanocortin receptor agonist melanotan II in mutant mice reversed alterations in glucose tolerance and glycosuria, whereas, conversely, administration of the antagonist Agouti-related peptide (Agrp) to wild-type mice enhanced glucose tolerance. The glycosuria of ArcPOMC-deficient mice was due to decreased levels of renal GLUT 2 (rGLUT2) but not sodium-glucose cotransporter 2 and was associated with reduced renal catecholamine content. Epinephrine treatment abolished the genotype differences in glucose tolerance and rGLUT2 levels, suggesting that reduced renal sympathetic nervous system (SNS) activity is the underlying mechanism for the observed glycosuria and improved glucose tolerance in ArcPOMC-deficient mice. Therefore, the ArcPOMC-SNS-rGLUT2 axis is potentially an insulin-independent therapeutic target to control diabetes.


Assuntos
Núcleo Arqueado do Hipotálamo/metabolismo , Glicemia/metabolismo , Transportador de Glucose Tipo 2/genética , Glicosúria Renal/genética , Resistência à Insulina/genética , Rim/metabolismo , Obesidade/genética , Pró-Opiomelanocortina/genética , Sistema Nervoso Simpático/metabolismo , Proteína Relacionada com Agouti/farmacologia , Animais , Glicemia/efeitos dos fármacos , Western Blotting , Epinefrina/metabolismo , Teste de Tolerância a Glucose , Transportador de Glucose Tipo 2/metabolismo , Glicosúria Renal/metabolismo , Hipotálamo/metabolismo , Injeções Intraventriculares , Camundongos , Camundongos Knockout , Norepinefrina/metabolismo , Obesidade/metabolismo , Peptídeos Cíclicos/farmacologia , Pró-Opiomelanocortina/deficiência , Pró-Opiomelanocortina/metabolismo , Receptores de Melanocortina/agonistas , Receptores de Melanocortina/antagonistas & inibidores , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia
13.
Mol Cell Endocrinol ; 411: 28-37, 2015 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-25892444

RESUMO

Melanocortins are neuropeptides with well recognized anti-inflammatory and anti-apoptotic effects in the brain. Of the five melanocortin receptors (MCR), MC4R is abundantly expressed in the brain and is the only MCR present in astrocytes. We have previously shown that MC4R activation by the α-melanocyte stimulating hormone (α-MSH) analog, NDP-MSH, increased brain-derived neurotrophic factor (BDNF) expression through the classic cAMP-Protein kinase A-cAMP responsive element binding protein pathway in rat astrocytes. Now, we examined the participation of the mitogen activated protein kinases pathway in MC4R signaling. Rat cultured astrocytes treated with NDP-MSH 1 µM for 1 h showed increased BDNF expression. Inhibition of extracellular signal-regulated kinase (ERK) and ribosomal p90 S6 kinase (RSK), an ERK substrate, but not of p38 or JNK, prevented the increase in BDNF expression induced by NDP-MSH. Activation of MC4R increased cFos expression, a target of both ERK and RSK. ERK activation by MC4R involves cAMP, phosphoinositide-3 kinase (PI3K) and the non receptor tyrosine kinase, Src. Both PI3K and Src inhibition abolished NDP-MSH-induced BDNF expression. Moreover, we found that intraperitoneal injection of α-MSH induces BDNF and MC4R expression and activates ERK and cFos in male rat hypothalamus. Our results show for the first time that MC4R-induced BDNF expression in astrocytes involves ERK-RSK-cFos pathway which is dependent on PI3K and Src, and that melanocortins induce BDNF expression and ERK-cFos activation in rat hypothalamus.


Assuntos
Astrócitos/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Hipotálamo/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Receptor Tipo 4 de Melanocortina/metabolismo , Transdução de Sinais/fisiologia , Animais , Astrócitos/efeitos dos fármacos , Células Cultivadas , Hipotálamo/efeitos dos fármacos , Masculino , Fosforilação/efeitos dos fármacos , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia
14.
JAMA Dermatol ; 151(1): 42-50, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25230094

RESUMO

IMPORTANCE: Narrowband UV-B (NB-UV-B) phototherapy is used extensively to treat vitiligo. Afamelanotide, an analogue of α-melanocyte-stimulating hormone, is known to induce tanning of the skin. OBJECTIVE: To evaluate the efficacy and safety of combination therapy for generalized vitiligo consisting of afamelanotide implant and NB-UV-B phototherapy. DESIGN, SETTING, AND PARTICIPANTS: This study was performed in 2 academic outpatient dermatology centers and 1 private dermatology practice. We enrolled men and women 18 years or older with Fitzpatrick skin phototypes (SPTs) III to VI and a confirmed diagnosis of nonsegmental vitiligo that involved 15% to 50% of total body surface area. Vitiligo was stable or slowly progressive for 3 months. Patients were randomized to combination therapy (n = 28) vs NB-UV-B monotherapy (n = 27). After 1 month of NB-UV-B phototherapy, 16 mg of afamelanotide was administered subcutaneously to the combination therapy group monthly for 4 months while NB-UV-B phototherapy continued; the other group continued to receive NB-UV-B monotherapy. INTERVENTIONS: Narrowband UV-B monotherapy vs combined NB-UV-B phototherapy and afamelanotide. MAIN OUTCOMES AND MEASURES: Response on the Vitiligo Area Scoring Index and Vitiligo European Task Force scoring system. RESULTS: Response in the combination therapy group was superior to that in the NB-UV-B monotherapy group (P < .05) at day 56. For the face and upper extremities, a significantly higher percentage of patients in the combination therapy group achieved repigmentation, and at earlier times (face, 41.0 vs 61.0 days [P = .001]; upper extremities, 46.0 vs 69.0 days [P = .003]). In the combination therapy group, repigmentation was 48.64% (95% CI, 39.49%-57.80%) at day 168 vs 33.26% (95% CI, 24.18%-42.33%) in the NB-UV-B monotherapy group. Notable adverse events included erythema in both groups and minor infections and nausea in the combination therapy group. Comparison between Fitzpatrick SPTs showed patients with SPTs IV to VI in the combination therapy group had improvement in the Vitiligo Area Scoring Index at days 56 and 84 (P < .05); no significant difference was noted in patients with SPT III. CONCLUSIONS AND RELEVANCE: A combination of afamelanotide implant and NB-UV-B phototherapy resulted in clinically apparent, statistically significant superior and faster repigmentation compared with NB-UV-B monotherapy. The response was more noticeable in patients with SPTs IV to VI. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01430195.


Assuntos
Terapia Ultravioleta/métodos , Vitiligo/terapia , alfa-MSH/análogos & derivados , Adolescente , Adulto , Idoso , Terapia Combinada , Progressão da Doença , Implantes de Medicamento , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Terapia Ultravioleta/efeitos adversos , Vitiligo/patologia , Adulto Jovem , alfa-MSH/efeitos adversos , alfa-MSH/uso terapêutico
16.
Neuropharmacology ; 85: 357-66, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24923239

RESUMO

The melanocortin receptor (MCR) system has been studied extensively for its role in feeding and sexual behavior, but effects on social behavior have received little attention. α-MSH interacts with neural systems involved in sociality, including oxytocin, dopamine, and opioid systems. Acute melanotan-II (MTII), an MC3/4R agonist, potentiates brain oxytocin (OT) release and facilitates OT-dependent partner preference formation in socially monogamous prairie voles. Here we examined the long-term impact of early-life MCR stimulation on hypothalamic neuronal activity and social development in prairie voles. Male and female voles were given daily subcutaneous injections of 10 mg/kg MTII or saline between postnatal days (PND) 1-7. Neonatally-treated males displayed a reduction in initiated play fighting bouts as juveniles compared to control males. Neonatal exposure to MTII facilitated partner preference formation in adult females, but not males, after a brief cohabitation with an opposite-sex partner. Acute MTII injection elicited a significant burst of the immediate early gene EGR-1 immunoreactivity in hypothalamic OT, vasopressin, and corticotrophin releasing factor neurons, when tested in PND 6-7 animals. Daily neonatal treatment with 1 mg/kg of a more selective, brain penetrant MC4R agonist, PF44687, promoted adult partner preferences in both females and males compared with vehicle controls. Thus, developmental exposure to MCR agonists lead to a persistent change in social behavior, suggestive of structural or functional changes in the neural circuits involved in the formation of social relationships.


Assuntos
Agressão/efeitos dos fármacos , Hipotálamo/efeitos dos fármacos , Ligação do Par , Psicotrópicos/farmacologia , Receptor Tipo 3 de Melanocortina/agonistas , Receptor Tipo 4 de Melanocortina/agonistas , Caracteres Sexuais , Agressão/fisiologia , Animais , Animais Recém-Nascidos , Arvicolinae , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Feminino , Hipotálamo/crescimento & desenvolvimento , Hipotálamo/fisiologia , Masculino , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Peptídeos Cíclicos/farmacologia , Jogos e Brinquedos , Distribuição Aleatória , Receptor Tipo 3 de Melanocortina/metabolismo , Receptor Tipo 4 de Melanocortina/metabolismo , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia
17.
Obesity (Silver Spring) ; 22(6): 1477-84, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24639082

RESUMO

OBJECTIVE: Androgen excess in women is associated with visceral adiposity. However, little is known on the mechanism through which androgen promotes visceral fat accumulation. METHODS: To address this issue, female mice to chronic androgen excess using 5α-dihydrotestosterone (DHT) and studied the regulation of energy homeostasis was exposed. RESULTS: DHT induced a leptin failure to decrease body weight associated with visceral adiposity but without alterations in leptin anorectic action. This paralleled leptin's failure to upregulate brown adipose tissue expression of uncoupling protein-1, associated with decreased energy expenditure (EE). DHT decreased hypothalamic proopiomelanocortin (pomc) mRNA expression and increased POMC intensity in neuronal bodies of the arcuate nucleus while simultaneously decreasing the intensity of POMC projections to the dorsomedial hypothalamus (DMH). This was associated with a failure of the melanocortin 4 receptor agonist melanotan-II to suppress body weight. CONCLUSION: Taken together, these data indicate that androgen excess promotes visceral adiposity with reduced POMC neuronal innervation in the DMH, reduced EE but without hyperphagia.


Assuntos
Adiposidade/fisiologia , Androgênios/administração & dosagem , Androgênios/sangue , Di-Hidrotestosterona/administração & dosagem , Di-Hidrotestosterona/sangue , Gordura Intra-Abdominal/efeitos dos fármacos , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/metabolismo , Androgênios/efeitos adversos , Animais , Núcleo Arqueado do Hipotálamo/efeitos dos fármacos , Núcleo Arqueado do Hipotálamo/metabolismo , Composição Corporal , Peso Corporal , Metabolismo Energético , Feminino , Hiperfagia/patologia , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Gordura Intra-Abdominal/metabolismo , Canais Iônicos/genética , Canais Iônicos/metabolismo , Leptina/sangue , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Obesidade/metabolismo , Peptídeos Cíclicos/metabolismo , Pró-Opiomelanocortina/genética , Pró-Opiomelanocortina/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptor Tipo 4 de Melanocortina/genética , Receptor Tipo 4 de Melanocortina/metabolismo , Proteína Desacopladora 1 , Regulação para Cima , alfa-MSH/análogos & derivados , alfa-MSH/metabolismo
18.
J Endocrinol ; 220(2): 97-107, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24204009

RESUMO

Obesity is a major burden to people and to health care systems around the world. The aim of the study was to characterize the effect of a novel selective α-MSH analog on obesity and insulin sensitivity. The subchronic effects of the selective MC4-R peptide agonist MC4-NN1-0182 were investigated in diet-induced obese (DIO) rats and DIO minipigs by assessing the effects on food intake, energy consumption, and body weight. The acute effect of MC4-NN1-0182 on insulin sensitivity was assessed by a euglycemic-hyperinsulinemic clamp study in normal rats. Three weeks of treatment of DIO rats with MC4-NN1-0182 caused a decrease in food intake and a significant decrease in body weight 7±1%, P<0.05 compared with 3±1% increase with the vehicle control. In DIO minipigs, 8 weeks of treatment with MC4-NN1-0182 resulted in a body weight loss of 13.3±2.5 kg (13±3%), whereas the vehicle control group had gained 3.7±1.4 kg (4±1%). Finally, clamp studies in normal rats showed that acute treatment with MC4-NN1-0182 caused a significant increase in glucose disposal (Rd) compared with vehicle control (Rd, mg/kg per min, 17.0±0.7 vs 13.9±0.6, P<0.01). We demonstrate that treatment of DIO rats or minipigs with a selective MC4-R peptide agonist causes weight loss. Moreover, we have demonstrated weight-independent effects on insulin sensitivity. Our observations identify MC4 agonism as a viable target for the treatment of obesity and insulin resistance.


Assuntos
Fármacos Antiobesidade/farmacologia , Resistência à Insulina , Obesidade/metabolismo , Redução de Peso/efeitos dos fármacos , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia , Animais , Dieta , Avaliação Pré-Clínica de Medicamentos , Feminino , Resistência à Insulina/fisiologia , Masculino , Obesidade/tratamento farmacológico , Obesidade/etiologia , Ratos , Ratos Sprague-Dawley , Suínos , Porco Miniatura , alfa-MSH/uso terapêutico
19.
Int J Drug Policy ; 25(3): 444-50, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24280586

RESUMO

BACKGROUND: Cultural values placed on tanned skin equating with perceived health and attractiveness in the Western world have stimulated the development, sale and use of synthetic tanning agents. These agents are synthetic analogues of the naturally occurring melanocyte-stimulating hormones (α-MSHs) which stimulate melanogenesis or pigmentation of the skin. There is a lack of research on prevalence of use, user experiences and outcomes, despite evident 'health marketability' and diffusion of use via the Internet. METHODS: We present a unique, intensive, holistic and exploratory single case study analysis of an active user's experiences of synthetic tanning product's labelled as melanotan, with rich description of the case's meanings and identities attached to being tanned, motives for use, injecting experiences and practices, sourcing routes, outcomes and future intentions to use. RESULTS: The case, an exotic dancer, had no prior drug injecting experience and did not identify as 'injecting drug user'. Introduction to injecting of synthetic tanning products occurred with peer assistance. She was conscious of safe injecting practices, which were described as not using needles twice, keeping the product refrigerated, disinfecting and rotating injecting sites, and using sterilised water to dissolve the product. She was aware of synthetic tanning products being unlicensed, unregulated and possibly contaminated. She appeared assured in the self-administration of double dosage and self-management of nausea with benzodiazepines and by injecting before sleep. Experiences of synthetic tanning were positive, with reported feelings of enhanced self-confidence and perceived attractiveness grounded in her confidence in the product's effectiveness to achieve a desired darkened skin tone. No long term or chronic negative outcomes were reported. Development of tolerance and awareness of dependence on synthetic tanning agents was described. CONCLUSION: We discuss her expert account as it relates to the synthetic tanning product outcomes, risk heuristics, sourcing routes and make recommendations for policy.


Assuntos
Dança/psicologia , Peptídeos Cíclicos/administração & dosagem , Pigmentação da Pele/efeitos dos fármacos , alfa-MSH/análogos & derivados , Feminino , Humanos , Injeções , Motivação , Peptídeos Cíclicos/efeitos adversos , Peptídeos Cíclicos/farmacologia , Autoadministração , Autoimagem , Adulto Jovem , alfa-MSH/administração & dosagem , alfa-MSH/efeitos adversos , alfa-MSH/farmacologia
20.
Domest Anim Endocrinol ; 45(2): 89-97, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23820242

RESUMO

Nesfatin-1, a product of the nucleobindin 2 (NUCB2) gene, purportedly plays important roles in whole-body energy homeostasis. Experiments were conducted to determine how NUCB2 expression in fat depots may be controlled in the pig and to test the hypothesis that nesfatin-1 regulates appetite and LH secretion in the gilt. Prepubertal gilts were used to study expression of NUCB2 in fat and the effects of intracerebroventricular (i.c.v.) injection of nesfatin-1 on food intake and pituitary hormone secretion. Growing pigs (gilts and barrows at 22 wk of age, n = 1,145) or sexually mature gilts (n = 439) were used to test association of SNP in the NUCB2 gene with growth traits. The expression of NUCB2 was similar for subcutaneous fat compared with perirenal fat. An i.c.v. injection of the melanocortin-4 receptor agonist [Nle4, d-Phe7]-α-melanocyte-stimulating hormone did not alter expression of NUCB2 mRNA in the hypothalamus but reduced (P = 0.056) NUCB2 mRNA expression in subcutaneous fat. Short-term (7 d) submaintenance feeding reduced (P < 0.05) BW and did not alter expression of mRNA for NUCB2, visfatin, or leptin but increased (P < 0.05) expression of adiponectin mRNA in fat. Central injection of nesfatin-1 suppressed (P < 0.001) feed intake. Secretion of LH was greater (P < 0.01) after i.c.v. injection of nesfatin-1 than after saline. Single nucleotide polymorphisms in the porcine NUCB2 gene were not associated with adiposity of growing pigs or age at puberty in gilts but were associated (P < 0.05) with BW at puberty. These data indicate that NUCB2 is expressed in fat depots of the pig and that the level of expression is sensitive to stimulation of appetite-regulating pathways in the hypothalamus. It is confirmed herein that nesfatin-1 can regulate appetite in the pig and affect the gonadotropic axis of the prepubertal pig. Association of SNP in the porcine NUCB2 gene with BW at puberty suggests that regulation of appetite by nesfatin-1 in the pig affects growth, which may have important consequences for adult phenotypes.


Assuntos
Proteínas de Ligação ao Cálcio/fisiologia , Proteínas de Ligação a DNA/fisiologia , Ingestão de Alimentos/fisiologia , Hormônio Luteinizante/metabolismo , Proteínas do Tecido Nervoso/fisiologia , Maturidade Sexual/fisiologia , Sus scrofa/fisiologia , Tecido Adiposo/química , Tecido Adiposo/metabolismo , Adiposidade/genética , Sequência de Aminoácidos , Animais , Regulação do Apetite/fisiologia , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/farmacologia , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/farmacologia , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Expressão Gênica/efeitos dos fármacos , Humanos , Hipotálamo/química , Injeções Intraventriculares , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/farmacologia , Nucleobindinas , Polimorfismo de Nucleotídeo Único/genética , RNA Mensageiro/análise , Receptor Tipo 4 de Melanocortina/agonistas , Alinhamento de Sequência , Sus scrofa/crescimento & desenvolvimento , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia
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