Methylation of the NR3C1 gene in individual with chronic pain: patient profile in a cross-sectional study with users of the public health system / Metilação do gene NR3C1 em indivíduos com dor crônica: perfil de pacientes em estudo transversal com usuários do sistema público de saúde

ABSTRACT BACKGROUND AND OBJECTIVES: Studies suggest that shared molecular factors can simultaneously affect different chronic pain syndromes. Understanding the epigenetic mechanisms of various diseases that are associated with chronic pain is essential to comprehend its appearance and progression. The objective of this study is to evaluate the association between DNA methylation of the NR3C1 gene with the presence and intensity of chronic pain, as well as predictive factors also considering socioeconomic, health and lifestyle factors correlated with this association, in adult individuals using the Brazilian Unified Health System (Sistema Único de Saúde - SUS) in a municipality in Southeast Brazil. METHODS: This is a cross-sectional study, whose data collection was carried out through interviews to investigate socioeconomic status, lifestyle and health conditions, in addition to anthropometric assessments and blood samples. Data were analyzed by quantitative DNA methylation assays and statistical analysis. CONCLUSION: The findings suggest epigenetic involvement in NR3C1 gene methylation in association with chronic pain and suggest the need to seek new evidence in relation to the mechanisms that explain chronic pain, especially from an epigenetic point of view, as they may provide subsidies for the prevention and control of chronic pain targeting individuals with the profile found in this study.

RESUMO JUSTIFICATIVA E OBJETIVOS: Estudos sugerem que fatores moleculares compartilhados podem afetar simultaneamente diferentes síndromes de dor crônica. Compreender os mecanismos epigenéticos de várias doenças que estão associadas à dor crônica é essencial para entender sua aparência e progressão. O objetivo deste estudo foi avaliar a associação entre metilação do DNA do gene NR3C1, receptor de glicocorticoides, com a presença e intensidade de dor crônica, bem como os fatores preditivos considerando também fatores socioeconômicos, de saúde e de estilo de vida correlacionados com tal associação em pacientes adultos usuários do Sistema Único de Saúde (SUS) em um município do sudeste brasileiro. MÉTODOS: Trata-se de um estudo observacional transversal, cuja coleta de dados foi realizada através de entrevistas para investigação do status socioeconômico, condições de estilo de vida e de saúde, além de avaliações antropométricas e coletas de sangue. Os dados foram analisados por meio de ensaios quantitativos de metilação do DNA e análise estatística. RESULTADOS: Foi observado que 123 participantes (44,1%) apresentaram metilação da região estudada do gene NR3C1. Análises estatísticas univariadas e multivariada mostraram que as variáveis idade e nível de cortisol estão significativamente associadas com a metilação do gene e a presença de dor crônica. CONCLUSÃO: Os achados sugerem envolvimento epigenético na metilação do gene NR3C1 em associação com dor crônica e sugerem a necessidade de se buscar novas evidências em relação aos mecanismos que explicam a dor crônica, sobretudo do ponto de vista epigenético, pois as mesmas poderão trazer subsídios para prevenção e controle da dor crônica visando pacientes com o perfil encontrado nesse estudo.

Mycobacterium leprae-helminth co-infections and vitamin D deficiency as potential risk factors for leprosy: A case-control study in south-eastern Brazil.

BACKGROUND: Evidence suggests that biological mechanisms involved in helminth infections and vitamin deficiencies increase susceptibility to other infections. The aim of this study was to investigate the associations of helminth co-infection and select micronutrient deficiencies with leprosy using a case-control design. METHODS: From 2016 to 2018, individuals aged ≥3 years were recruited at clinics in and around Governador Valadares, Minas Gerais, Brazil in three groups: cases of leprosy, household contacts and community-matched (non-contact) controls. Helminths were diagnosed through stool Kato Katz examination and serum reactivity to anti-soluble adult worm antigen preparation IgG4. Serum ferritin, 25-OH vitamin D and retinol concentrations were measured. Multi-variate logistic regression was conducted to identify associations with active leprosy. RESULTS: Seventy-nine cases of leprosy, 96 household contacts and 81 non-contact controls were recruited; 48.1% of participants were male with a median age of 40 years. Helminths were found in 7.1% of participants on Kato Katz test, all but one of which were Schistosoma mansoni, and 32.3% of participants were positive for S. mansoni serology. On multi-variate analysis, cases were more likely to be infected with helminths (diagnosed by stool) than household contacts [adjusted odds ratio (aOR) 8.69, 95% confidence interval (CI) 1.50-50.51]. Vitamin D deficiency was common, and was more likely in cases compared with non-contact controls (aOR 4.66, 95% CI 1.42,-15.33). Iron deficiency was not associated with leprosy, and vitamin A deficiency was not detected. CONCLUSION: These associations suggest that the immune consequences of schistosomiasis and vitamin D deficiency may increase the risk of active leprosy. Comorbid conditions of poverty deserve further study as addressing co-infections and nutritional deficiencies could be incorporated into programmes to improve leprosy control.

Differentiation of patients with leprosy from non-infected individuals by the chemokine eotaxin/CCL11.

Diagnosis of leprosy is usually made clinically and there are no tests available for the routine laboratory diagnosis of the disease. The aim of this study was to investigate the potential role of chemokines as biologic markers of disease activity. We used an enzyme-linked immunosorbent assay to measure chemokines in plasma of patients with leprosy (LE) and non-infected (NI) individuals. There were significantly greater concentrations of the chemokines CCL3 and CCL11 in plasma of LE patients than in NI individuals. When the use of CCL11 to differentiate LE patients versus NI individuals was evaluated, the area under the receiver-operator-characteristic curve was 0.95 +/- 0.03 (P < 0.0001). In a group of selected individuals, CCL11 was useful in diagnosis of leprosy, thereby suggesting that measurement of this chemokine may be useful as an aid in diagnosing leprosis.