Shim Raymond, Wilson Jenny L, Phillips Sarah E, Lambert Gavin W, Wen Shu Wen, Wong Connie H Y
Centre for Inflammatory Diseases, Department of Medicine, School of Clinical Sciences at Monash Health, Monash Medical Centre, Monash University, Clayton, Victoria, Australia.
Inversion Health Innovation Research Institute and School of Health Sciences, Swinburne University of Technology, Victoria, Australia.
Brain Behav Immun Health. 2021 Nov 23;18:100393. doi: 10.1016/j.bbih.2021.100393. eCollection 2021 Dec.
Mechanisms underlying post-stroke immune impairments and subsequent development of fatal lung infection have been suggested to involve multiple pathways, including hyperactivation of the sympathetic nervous system (SNS), which results in the excessive release of catecholamines and activation of β-adrenergic receptors (βARs). Indeed, previous reports from experimental studies demonstrated that post-stroke infection can be inhibited with treatment of β-blockers. However, the effectiveness of β-blockers in reducing post-stroke infection has yielded mixed results in retrospective clinical trials and its use remain controversial. In this study, we performed mid-cerebral artery occlusion in mice either genetically deficient in β-adrenergic receptor (βAR) or treated with non-selective and selective βAR antagonists to explore the contributions of the SNS in the development of post-stroke lung infection. Stroke induced a systemic activation of the SNS as indicated by elevated levels of plasma catecholamines and UCP-1 activity. However, βAR deficient mice showed similar degrees of post-stroke immune impairment and infection rate compared to wildtype counterparts, potentially due to compensatory mechanisms common in transgenic animals. To overcome this, we treated post-stroke wildtype mice with pharmacological inhibitors of the βARs, including the non-selective antagonist propranolol (PPL) and selective βAR antagonist ICI-118551. Both pharmacological strategies to block the action of SNS signalling were unable to reduce infection in mice that underwent ischaemic stroke. Overall, our data suggests that other mechanisms independent or in combination with βAR activation contribute to the development of post-stroke infection.
中风后免疫功能受损及随后发生致命肺部感染的潜在机制已被认为涉及多种途径,包括交感神经系统(SNS)的过度激活,这会导致儿茶酚胺的过度释放和β-肾上腺素能受体(βARs)的激活。事实上,先前实验研究的报告表明,β受体阻滞剂治疗可抑制中风后的感染。然而,β受体阻滞剂在减少中风后感染方面的有效性在回顾性临床试验中结果不一,其使用仍存在争议。在本研究中,我们对β-肾上腺素能受体(βAR)基因缺陷的小鼠或用非选择性和选择性βAR拮抗剂治疗的小鼠进行大脑中动脉闭塞,以探讨SNS在中风后肺部感染发展中的作用。中风导致SNS的全身激活,血浆儿茶酚胺水平升高和UCP-1活性升高表明了这一点。然而,与野生型小鼠相比,βAR缺陷小鼠表现出相似程度的中风后免疫功能受损和感染率,这可能是由于转基因动物中常见的补偿机制。为了克服这一点,我们用βARs的药理学抑制剂治疗中风后的野生型小鼠,包括非选择性拮抗剂普萘洛尔(PPL)和选择性βAR拮抗剂ICI-118551。这两种阻断SNS信号传导作用的药理学策略均无法降低缺血性中风小鼠的感染率。总体而言,我们的数据表明,其他独立或与βAR激活相结合的机制促成了中风后感染的发展。