BDNF gene polymorphysm RS2049046 in episodic and chronic migraine

Interaction between job stress, serum BDNF level and the BDNF rs2049046 polymorphism in job burnout

BACKGROUND

Some studies have shown that long-term exposure to job stress could result in burnout, and BDNF polymorphism may play an important role in its psychopathological mechanism. However, the inter-relationships between the job-related stress, serum BDNF level, BDNF genotype and job burnout have not been examined. This study was to explore the job stress × BDNF rs2049046 interaction and the role of serum BDNF level in job burnout in a Chinese Han population.

METHODS

Using a cross-sectional design, 205 healthy subjects were recruited from a public institution in Beijing and assessed for job stress using the House and Rizzo's Work Stress Scale, and job burnout using the Maslach Burnout Inventory (MBI). The BDNF rs2049046 polymorphism was genotyped and serum BDNF (sBDNF) levels were assayed in all of subjects.

RESULTS

The correlations between the job stress score and two burnout subscale scores (emotional exhaustion and cynicism) were significant (both p < 0.001), but not with professional efficacy. There were no significant main effects of the BDNF rs2049046 genotype on burnout, and no significant correlation was observed between sBDNF levels and job burnout. However, the interaction between the job stress and the BDNF rs2049046 genotype (F = 2.709, df = 2, 183, p = 0.032) or between the job stress and sBDNF levels on burnout was significant (t = -2.132, p = 0.035). To be specific, the individuals with the BDNF rs2049046 AT genotype showed a greater susceptibility to the burnout cynicism compared to AA homozygote only in medium-stress group (F = 4.327, df = 1,117, p = 0.015). The individuals who had lower sBDNF showed higher burnout level than those who had higher sBDNF in low-stress group.

CONCLUSIONS

Our findings suggest that the BDNF system may interact with job stress to affect burnout, showing that interaction between BDNF rs2049046 and job stress or the interaction between BDNF levels with work stress on certain burnout dimensions.

Interactions of BDNF Val66Met Polymorphism and Menstrual Pain on Brain Complexity

The irregularity and uncertainty of neurophysiologic signals across different time scales can be regarded as neural complexity, which is related to the adaptability of the nervous system and the information processing between neurons. We recently reported general loss of brain complexity, as measured by multiscale sample entropy (MSE), at pain-related regions in females with primary dysmenorrhea (PDM). However, it is unclear whether this loss of brain complexity is associated with inter-subject genetic variations. Brain-derived neurotrophic factor (BDNF) is a widely expressed neurotrophin in the brain and is crucial to neural plasticity. The BDNF Val66Met single-nucleotide polymorphism (SNP) is associated with mood, stress, and pain conditions. Therefore, we aimed to examine the interactions of BDNF Val66Met polymorphism and long-term menstrual pain experience on brain complexity. We genotyped BDNF Val66Met SNP in 80 PDM females (20 Val/Val, 31 Val/Met, 29 Met/Met) and 76 healthy female controls (25 Val/Val, 36 Val/Met, 15 Met/Met). MSE analysis was applied to neural source activity estimated from resting-state magnetoencephalography (MEG) signals during pain-free state. We found that brain complexity alterations were associated with the interactions of BDNF Val66Met polymorphism and menstrual pain experience. In healthy female controls, Met carriers (Val/Met and Met/Met) demonstrated lower brain complexity than Val/Val homozygotes in extensive brain regions, suggesting a possible protective role of Val/Val homozygosity in brain complexity. However, after experiencing long-term menstrual pain, the complexity differences between different genotypes in healthy controls were greatly diminished in PDM females, especially in the limbic system, including the hippocampus and amygdala. Our results suggest that pain experience preponderantly affects the effect of BDNF Val66Met polymorphism on brain complexity. The results of the present study also highlight the potential utilization of resting-state brain complexity for the development of new therapeutic strategies in patients with chronic pain.