第二型糖尿病與阿茲海默氏症的關聯性

流行病學研究證實，第二型糖尿病（Type 2 diabetes mellitus, T2DM）與阿茲海默氏症（Alzheimer’s disease, AD）之間確實存有生理病理性的關聯，此類糖尿病病人具有較高之認知障礙的發生率，也因此具有較高罹患AD的風險，因此，T2DM已成為AD的危險因子之一。T2DM與AD的共同致病因子包含慢性高血糖、高胰島素血症、胰島素阻抗、突發性的急性低血糖（尤其在老人患者）、纖維性的沉積（AD病人的腦部及T2DM病人的胰臟）、胰島素訊息傳導的改變、發炎、肥胖及APOE4基因等。此外，AD病人併發T2DM者（又稱第三型糖尿病）可加重其臨床疾病表現。本文於分子、生化及組織病理層面，整理歸納T2DM和AD可能之關聯性的存在證據。藉由這些資訊盼能進一部描述這兩個疾病之間較具體的致病機轉，期望能在未來對治療第三型糖尿病的藥物研發有所助益。

Epidemiological studies have proved that there are pathophysiological connections between Type 2 diabetes mellitus (T2DM) and Alzheimer’s disease (AD). Diabetic patients have higher incidences of cognitive impairment and hence they are more at the risk of developing AD. Therefore, T2DM is a risk factor for AD, although AD pathological marker studies have not provided sufficient evidence. Common pathogenic factors in both conditions including chronic hyperglycemia episodes, especially in the elderly, fibrillar deposits (in brain in AD and in pancreas in T2DM), altered insulin signaling, inflammation, obesity and APOE4 carrier status. In addition, comorbid T2DM can worsen the clinical presentations of patients with AD. This review summarizes the evidences which establish the possible links between the two pathologies on the account of molecular, biochemical and at histopathological level. The information regarding their interactions will clearly establish the link between the two pathologies and will be helpful in the future for the development of drugs for Type 3 Diabetes.