Aerobic capacity and mitochondrial function in bipolar disorder: a longitudinal study during acute phases and after clinical remission.

Background: Aerobic capacity has shown to predict physical and mental health-related quality of life in bipolar disorder (BD). However, the correlation between exercise respiratory capacity and mitochondrial function remains understudied. We aimed to assess longitudinally intra-individual differences in these factors during mood episodes and remission in BD. Methods: This study included eight BD patients admitted to an acute psychiatric unit. Incremental cardiopulmonary exercise test (CPET) was conducted during acute episodes (T0), followed by constant work rate cycle ergometry (CWRCE) to evaluate endurance time, oxygen uptake at peak exercise (VO2peak) and at the anaerobic threshold. The second test was repeated during remission (T1). Mitochondrial respiration rates were assessed at T0 and T1 in peripheral blood mononuclear cells. Results: Endurance time, VO2peak, and anaerobic threshold oxygen consumption showed no significant variations between T0 and T1. Basal oxygen consumption at T1 tended to inversely correlate with maximal mitochondrial respiratory capacity (r=-0.690, p=0.058), and VO2peak during exercise at T1 inversely correlated with basal and minimum mitochondrial respiration (r=-0.810, p=0.015; r=-0.786, p=0.021, respectively). Conclusions: Our preliminary data showed that lower basal oxygen consumption may be linked to greater mitochondrial respiratory capacity, and maximum oxygen uptake during the exercise task was associated with lower basal mitochondrial respiration, suggesting that lower oxygen requirements could be associated with greater mitochondrial capacity. These findings should be replicated in larger samples stratified for manic and depressive states.

Reduced mitochondrial respiratory capacity in patients with acute episodes of bipolar disorder: Could bipolar disorder be a state-dependent mitochondrial disease?

BACKGROUND: Bipolar disorder (BD) is a chronic and recurrent disease characterized by acute mood episodes and periods of euthymia. The available literature postulates that a biphasic dysregulation of mitochondrial bioenergetics might underpin the neurobiology of BD. However, most studies focused on inter-subject differences rather than intra-subject variations between different mood states. To test this hypothesis, in this preliminary proof-of-concept study, we measured in vivo mitochondrial respiration in patients with BD during a mood episode and investigated differences compared to healthy controls (HC) and to the same patients upon clinical remission. METHODS: This longitudinal study recruited 20 patients with BD admitted to our acute psychiatric ward with a manic (n = 15) or depressive (n = 5) episode, and 10 matched HC. We assessed manic and depressive symptoms using standardized psychometric scales. Different mitochondrial oxygen consumption rates (OCRs: Routine, Leak, electron transport chain [ETC], Rox) were assessed during the acute episode (T0) and after clinical remission (T1) using high-resolution respirometry at 37°C by polarographic oxygen sensors in a two-chamber Oxygraph-2k system in one million of peripheral blood mononuclear cells (PMBC). Specific OCRs were expressed as mean ± SD in picomoles of oxygen per million cells. Significant results were adjusted for age, sex, and body mass index. RESULTS: The longitudinal analysis showed a significant increase in the maximal oxygen consumption capacity (ETC) in clinical remission (25.7 ± 16.7) compared to the acute episodes (19.1 ± 11.8, p = 0.025), and was observed separately for patients admitted with a manic episode (29.2 ± 18.9 in T1, 22.3 ± 11.9 in T0, p = 0.076), and at a trend-level for patients admitted with a depressive episode (15.4 ± 3.9 in T1 compared to 9.4 ± 3.2 in T0, p = 0.107). Compared to HC, significant differences were observed in ETC in patients with a bipolar mood episode (H = 11.7; p = 0.003). Individuals with bipolar depression showed lower ETC than those with a manic episode (t = -3.7, p = 0.001). Also, significant differences were observed in ETC rates between HC and bipolar depression (Z = 1.000, p = 0.005). CONCLUSIONS: Bioenergetic and mitochondrial dysregulation could be present in both manic and depressive phases in BD and, importantly, they may restore after clinical remission. These preliminary results suggest that mitochondrial respiratory capacity could be a biomarker of illness activity and clinical response in BD. Further studies with larger samples and similar approaches are needed to confirm these results and identify potential biomarkers in different phases of the disease.

Psychosocial Risks and Mental Disorders among Mexican Oil Workers / Riesgos psicosociales y trastornos mentales en trabajadores petroleros mexicanos / Riscos psicossociais e transtornos mentais em trabalhadores petrolíferos mexicanos

The psychosocial risks faced by workers can influence their health as well as job performance and satisfaction. However, this phenomenon among Mexican workers in the oil industry has not been well studied. The purpose of this study was to analyze the association of stress and job-related burnout with mental disorders among oil workers in the southeastern region of Mexico. Materials and methods: This cross-sectional and analytical study included 501 workers from the onshore oil industry in the southeastern region of Mexico. The Work Burnout Inventory, the Symptoms of Stress Inventory, and the Goldberg General Health Questionnaire (ghq 28) were applied between October and November, 2016. Chi-square test was used to analyze the relationship between variables and the odds ratio was determined to establish the level of risk for mental disorders. Results: Moderate levels of stress (21.4l %), efficacy (41.5 %), cynicism (30.6 %), and exhaustion (39.7 %) were observed. Mental disorders were noted in 11.8 % of workers. Stress and burnout were associated with mental disorders (p < 0.05). Finally, workers who experienced stress and job burnout were more likely to have mental disorders (or = 12.96; 95 % ci [7.03­23.94]; p = 0.00). Conclusions:Stress and job burnout are risk factors for mental disorders among Mexican oil workers.

los riesgos psicosociales en los trabajadores tienen influencia en la salud, rendimiento del trabajo y satisfacción laboral; sin embargo, poco se ha estudiado este fenómeno en los trabajadores mexicanos de la industria petrolera. El objetivo fue analizar la asociación entre estrés y desgaste laboral y trastornos en los trabajadores de la industria petrolera terrestre de la región sureste de México. Materiales y métodos: diseño transversal y analítico. La muestra estuvo integrada por 501 trabajadores. Los instrumentos utilizados fueron el Inventario de Desgaste Laboral, el Inventario de Síntomas de Estrés y el Cuestionario de Salud General de Goldberg (ghq 28). Se aplicaron los instrumentos entre octu-bre y noviembre de 2016. Se utilizó la prueba de chi cuadrado para analizar la relación entre las variables, y se determinaron odds ratio para establecer el nivel de riesgo a trastornos mentales. Resultados: se encontraron niveles moderados de estrés (21.4l %), eficacia (41.5 %), cinismo (30.6 %) y agotamiento (39.7 %). Se encontró presencia de trastornos mentales en el 11.8 % de los trabajadores. El estrés y las dimensiones del desgaste laboral se asociaron con los trastornos mentales (p < 0.05). Finalmente, los tra-bajadores que presentaron estrés y desgaste laboral tuvieron mayor probabilidad de sufrir trastornos mentales (or= 12.96; ic 95 % [7.03-23.94]; p = 0.00). Conclusiones: el estrés y el desgaste laboral representan factores de riesgo para presentar trastornos mentales en los trabajadores petroleros mexicanos.

os riscos psicossociais nos trabalhadores influenciam a saúde, o desempenho no trabalho e a satisfação no trabalho, no entanto, esse fenômeno tem sido pouco estudado em trabalhadores mexi-canos da indústria petrolífera. O objetivo do estudo foi analisar a associação do estresse e desgaste no trabalho com transtornos em trabalhadores da indústria petrolífera terrestre da região sudeste do México. Materiais e métodos: desenho transversal e analítico. A amostra foi composta por 501 trabalha-dores. Os instrumentos utilizados foram o Inventário de Desgaste Laboral, o Inventário de Sintomas de Estresse e o Questionário de Saúde Geral de Goldberg (ghq 28). Os instrumentos foram aplicados entre outubro e novembro de 2016. O teste qui-quadrado foi utilizado para analisar a relação entre as variáveis e o odds ratio foi determinado para estabelecer o nível de risco para transtornos mentais. Resultados: foram encontrados níveis moderados de estresse (21,4l %), eficácia (41,5 %), cinismo (30,6 %) e exaustão (39,7 %). A presença de transtornos mentais foi encontrada em 11,8 % dos trabalhadores. O estresse e as dimensões de desgaste laboral foram associadas aos transtornos mentais (p < 0,05). Por fim, os trabalhadores que apresentavam estresse e desgaste laboral apresentaram maior probabilidade de apresentar transtornos mentais (or = 12,96; ic 95 % [7,03-23,94]; p = 0,00). Conclusões: o estresse e desgaste laboral representam fatores de risco para o desenvolvimento de transtornos mentais em trabalhadores petrolíferos mexicanos.