O'Connor Mary-Frances, Motivala Sarosh J, Valladares Edwin M, Olmstead Richard, Irwin Michael R
Cousins Center for Psychoneuroimmunology, UCLA Semel Institute for Neuroscience and Human Behavior, University of California-Los Angeles, 300 Medical Plaza, Los Angeles, CA 90095-7076, USA.
Am J Physiol Regul Integr Comp Physiol. 2007 Jul;293(1):R145-51. doi: 10.1152/ajpregu.00752.2006. Epub 2007 Apr 11.
Sex differences in the prevalence of inflammatory disorders exist, perhaps due to sex differences in cellular mechanisms that contribute to proinflammatory cytokine activity. This study analyzed sex differences of monocyte intracellular expression of IL-6 and its associations with reproductive hormones and autonomic mechanisms in 14 matched pairs of men and women (n = 28). Monocyte intracellular IL-6 production was repeatedly assessed over two circadian periods. Sympathetic balance was estimated by heart rate variability and the ratio of power in the low-frequency (LF) to high-frequency (HF); vagal tone was indexed by the power of HF component. As compared to men, women showed greater monocyte expression of IL-6 across the circadian period. In addition, women showed lower sympathetic balance (LF/HF ratio), and greater levels of vagal tone (HF power). In women, but not men, sympathovagal balance was negatively associated with monocyte IL-6 expression, whereas vagal tone was positively associated with production of this cytokine. Levels of reproductive hormones were not related to monocyte IL-6 expression. The marked increase in monocyte expression of interleukin-6 in women has implications for understanding sex differences in risk of inflammatory disorders. Additionally, these data suggest that sex differences in sympathovagal balance or vagal tone may be a pathway to explain sex differences in IL-6 expression. Interventions that target autonomic mechanisms might constitute new strategies to constrain IL-6 production with impacts on inflammatory disease risk in women.
炎症性疾病的患病率存在性别差异，这可能是由于促成促炎细胞因子活性的细胞机制存在性别差异所致。本研究分析了14对匹配的男性和女性（n = 28）中单核细胞内白细胞介素-6（IL-6）的表达及其与生殖激素和自主神经机制的关联。在两个昼夜周期内反复评估单核细胞内IL-6的产生情况。通过心率变异性以及低频（LF）与高频（HF）功率之比来估计交感神经平衡；迷走神经张力以HF成分的功率为指标。与男性相比，女性在整个昼夜周期中单核细胞IL-6的表达更高。此外，女性的交感神经平衡较低（LF/HF比值），迷走神经张力水平较高（HF功率）。在女性而非男性中，交感迷走神经平衡与单核细胞IL-6表达呈负相关，而迷走神经张力与该细胞因子的产生呈正相关。生殖激素水平与单核细胞IL-6表达无关。女性单核细胞中白细胞介素-6表达的显著增加对于理解炎症性疾病风险中的性别差异具有重要意义。此外，这些数据表明交感迷走神经平衡或迷走神经张力的性别差异可能是解释IL-6表达性别差异的一条途径。针对自主神经机制的干预措施可能构成新的策略，以抑制IL-6的产生，从而影响女性的炎症性疾病风险。
