Clarification of eosinophilic chemoattractants in chronic subdural hematoma outer membrane

2021 Fiscal Year Final Research Report

• Project/Area Number: 17K10853
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Neurosurgery
• Research Institution: Aichi Medical University
• Principal Investigator: Osuka Koji 愛知医科大学, 看護学部, 教授 (40378013)
• Co-Investigator(Kenkyū-buntansha): 渡辺 泰男 昭和薬科大学, 薬学部, 教授 (10273228) ; 高安 正和 愛知医科大学, 公私立大学の部局等, 名誉教授 (60216794)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Keywords: 慢性硬膜下血腫 / 好酸球 / eotaxin-3

Outline of Final Research Achievements

Eosinophils induce inflammation by releasing cytokines and cytotoxic granule proteins. Infiltration of eosinophilic granulocytes occurs in the outer membrane of chronic subdural hematomas (CSDHs). Eosinophils play an important role in the growth of CSDHs. In the current study, we assessed the expression of eosinophil chemoattractants in CSDH fluids according to the growth stage of the CSDHs. CSDH fluids were obtained from 38 patients during trepanation surgery. The concentrations of ecalectin, eotaxin-3, interleukin-5 (IL-5) and eosinophil-derived neurotoxin (EDN) were high in the CSDH fluids. The levels of eotaxin-3, IL-5, EDN and %eosinophil were significantly higher in the laminar type of CSDH. The correlations between eotaxin-3 and IL-5, IL-5 and EDN, and EDN and %eosinophil were statistically significant (p<0.01). Our data suggest that eotaxin-3 is a chemoattractant of eosinophils. IL-5 induces the activation of eosinophils following the degranulation of EDN into CSDH fluids.

Free Research Field

脳神経外科

Academic Significance and Societal Importance of the Research Achievements

慢性硬膜下血腫は、高齢者において軽微な頭部外傷後に発生し認知症状や脳卒中様症状を伴うなど高齢化社会において避けられない疾患である。慢性硬膜下血腫の被膜は、新生血管ならびに好酸球、肥満細胞などの炎症性細胞などからなりたっており、これら炎症性細胞が血腫被膜の増大に果たす役割は大きいと考えられる。
今回の研究成果から、eotaxin-3は好酸球を誘導し、 interleukin-5が好酸球を成熟させ、好酸球からEDNの放出に関与していることが判明した。これらの因子を対象とした新たな慢性硬膜下血腫に対する治療法が大いに期待するところである。