RESUMO
Spinocerebellar ataxia type 2 (SCA2) is a progressive neurodegenerative disorder due to an unstable expansion of a CAG repeat in the ATXN2 gene. Despite clinical and experimental evidence indicating the relevance of the gonadotropic axis to the prognosis and therapeutics for several late-onset neurodegenerative disorders, its functioning and association with disease severity have not been previously explored in SCA2. To assess serum levels of testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH), and their clinical relevance in SCA2 patients. A case-control study involving 94 Cuban SCA2 patients and 101 gender- and age-matched healthy controls was conducted. Testosterone, LH, and FSH serum levels were determined by radioimmunoassay or immunoradiometric assay systems. Clinical outcomes included age at onset, disease duration, Scale for the Assessment and Rating of Ataxia (SARA) score, and progression rate. Univariate general linear models were generated. Testosterone, LH, and FSH serum levels were significantly reduced in male SCA2 patients relative to control individuals. On average, there was a 35% reduction in testosterone levels in male patients versus male control individuals. Testosterone levels were associated with disease duration (r = 0.383; p = 0.025) and age at onset (r = 0.414; p = 0.011) in male SCA2 patients, but no association was observed between testosterone and CAG expansion size, SARA score, or progression rate. Testosterone levels might be a biomarker of disease progression in male SCA2 patients. Further studies are needed to explore the effects of low testosterone levels on non-motor symptoms, and to assess the potential of testosterone replacement therapy in male SCA2 patients.
Assuntos
Ataxias Espinocerebelares/sangue , Testosterona/sangue , Adulto , Idade de Início , Estudos de Casos e Controles , Hormônio Foliculoestimulante/sangue , Humanos , Hormônio Luteinizante/sangue , Masculino , Pessoa de Meia-IdadeRESUMO
RESUMEN Introducción: Varias proteinopatías del sistema nervioso están asociadas a la ocurrencia de alteraciones en componentes del eje hipotálamo-hipófisis-gonadal. Objetivo: Reflejar la relevancia de componentes del eje hipotálamo-hipófisis-gonadal en la fisiopatología de proteinopatías del sistema nervioso. Material y Métodos: Se realizó una revisión bibliográfica durante los meses de enero de 2018 a diciembre de 2018. Fueron consultadas bases de datos de referencia, con el uso de descriptores y operadores booleanos. La estrategia de búsqueda avanzada para la selección de los artículos fue empleada, teniendo en cuenta la calidad metodológica o validez de los estudios. Desarrollo: Fueron identificaron alteraciones del funcionamiento normal del eje hipotálamo-hipófisis-gonadal en varias proteinopatías del sistema nervioso. Las alteraciones más frecuentemente reportadas fueron el incremento en los niveles de gonadotropinas, principalmente de la hormona luteinizante, en la enfermedad de Alzheimer, y la disminución de los niveles de testosterona en las enfermedades de Alzheimer, Parkinson, Huntington y Esclerosis Lateral Amiotrófica, con el consiguiente agravamiento del fenotipo clínico. Se obtuvieron evidencias de naturaleza preliminar, que fundamentan la posible ocurrencia de disfunción hipotalámica en pacientes con ataxias espinocerebelosas. Conclusiones: Aun cuando existen evidencias que demuestran la existencia de un vínculo entre la fisiopatología de proteinopatías del sistema nervioso y alteraciones en componentes del eje hipotálamo-hipófisis-gonadal, se requerirán estudios más extensos e integrales para confirmar estas asociaciones y para caracterizar los mecanismos moleculares implicados.
ABSTRACT Introduction: Several proteinopathies of the nervous system are associated with disturbances in components of the hypothalamic-pituitary-gonadal axis. Objective: To assess the relevance of components of the hypothalamic-pituitary-gonadal axis in the pathophysiology of proteinopathies of the nervous system. Material and Methods: A literature review was carried out from January to December 2018. Several databases were searched by using descriptors and Boolean operators. Advanced search strategy was used for the selection of articles, taking into account the methodological quality and validity of the studies. Results: Disturbances of the normal function of the hypothalamic-pituitary-gonadal axis were identified in proteinopathies of the nervous system. The most frequently reported disturbances were the increase in gonadotropin levels, mainly in luteinizing hormone in Alzheimer´s disease, and the decrease in testosterone levels in Alzheimer´s, Parkinson´s and Huntington´s diseases, and Amyotrophic Lateral Sclerosis, with the resulting worsening of the clinical phenotype. Preliminary evidence was obtained, which was pointing to a possible hypothalamic dysfunction in Spinocerebellar ataxia patients. Conclusions: Even when evidences were gathered supporting a link between the pathophysiology of proteinopathies of the nervous system and disturbances in components of the hypothalamic-pituitary-gonadal axis, deeper and more comprehensive studies will be needed to confirm these associations and to characterize the underlying molecular mechanisms.