Airway inflammation in a novel mouse model of asthma-COPD overlap induced by co-exposure to papain and tobacco smoke.

Asthma and chronic obstructive pulmonary disease (COPD) are respiratory diseases associated with airway inflammation, which is the main pathogenesis. Although their causes and characteristics differ, in some cases, asthma and COPD may coexist in the same patient in a condition called asthma-COPD overlap (ACO). The prognosis of ACO is more unfavourable than those of asthma or COPD alone, without any treatment strategies demonstrating efficacy. Owing to its intricate spectrum of features, the detailed pathogenesis of how ACO exacerbates respiratory features remains unclear. In this study, we exposed papain-induced asthma model mice to tobacco smoke to establish an ACO mouse model, in which features of airway inflammation observed in both asthma and COPD were incorporated. This model exhibited distinctive mixed and corticosteroid-resistant airway inflammation and emphysematous changes that are characteristic of ACO. The novel mouse model established here is expected to significantly contribute to elucidating the mechanisms of the broad pathologies of ACO and identifying potential therapeutic targets.

MR vessel wall enhancement in a pediatric focal cerebral arteriopathy.

BACKGROUND: Focal cerebral arteriopathy (FCA) is a common cause of childhood arterial ischemic stroke in previously healthy children. Although its mechanisms are poorly understood, recent studies have suggested inflammatory processes. Magnetic resonance vessel wall imaging (VWI) is a potential imaging biomarker of inflammation. CASE DESCRIPTION: We describe the case of a 7-year-old Japanese girl with right hemiplegia and dysarthria for 3 days. Brain MRI showed acute infarct in the left basal ganglia, and MRA and conventional cerebral angiogram detected vascular stenosis in the left distal internal carotid artery, left M1 and A1 segments. VWI revealed marked vessel wall enhancement and thickening in the left carotid artery, M1, and A2 segments. Based on imaging findings, she was diagnosed with acute ischemic stroke caused by FCA. Because VWI findings were thought to suggest vessel wall inflammation, high-dose steroid therapy was administered in addition to neuroprotective care and antithrombotic therapy. Although her clinical symptoms improved immediately, cerebral arteriopathy worsened on MRA a month after the onset. Subsequently, after 3 months of steroid therapy, vessel wall enhancement on VWI decreased, while arterial stenosis partially improved. At the follow-up 9 months after the onset, she had no recurrent stroke, her arteriopathy had stabilized. DISCUSSION: Definitive evidence of inflammatory mechanisms in FCA is limited, and appropriate management and treatment strategies for FCA are undefined. VWI attempts to demonstrate pathologic processes within the vessel wall, and reversible wall enhancement observed in our patient suggested the presence of inflammation. VWI would help in the evaluation of disease activity in FCA. CONCLUSION: VWI may contribute to the appropriate diagnosis and treatment for FCA to reflect active inflammation. Further work is needed to assess the utility of VWI in pediatric FCA.