腎と骨代謝 Vol.32 No.4(3)


特集名 軟部組織の石灰化 ─ 血管と心臓弁
題名 血管石灰化促進の病態─内膜石灰化と中膜石灰化の違い
発刊年月 2019年 10月
著者 塩井 淳 大阪市立大学大学院医学研究科血管病態制御学
著者 絵本 正憲 大阪市立大学大学院医学研究科代謝内分泌病態内科学
【 要旨 】 血管石灰化は血管壁にリン酸カルシウムが沈着する異所性石灰化であり,心血管イベントの発症と関連する重要な病態であると理解されている.血管石灰化はその沈着部位により内膜石灰化と中膜石灰化の二つに大別される.内膜石灰化は動脈硬化性プラークに認められる石灰化で,内腔狭窄やプラークの破綻などにより動脈硬化性疾患(心筋梗塞,脳梗塞,閉塞性動脈硬化症)の発症に関与する.一方,中膜石灰化は中膜内に全周性に進展する石灰化で動脈壁硬化を引き起こし,心不全,左室肥大,拡張機能障害などをもたらす.これらの石灰化の発症には,骨芽細胞への形質転換,基質小胞による石灰化など共通の機序が関与している.内膜石灰化が炎症主体の病態で促進されるのに対して中膜石灰化は代謝異常主体の病態で促進される.両方の石灰化を促進する病態である加齢,糖尿病,慢性腎臓病では,両方の因子が関与しているものと推察される.
Theme Ectopic calcification on soft tissue: Vascular calcification and cardiac valvular calcification
Title Pathophysiological conditions accelerating vascular calcification: the differences between intimal and medial calcification
Author Atsushi Shioi Department of Vascular Medicine, Osaka City University Graduate School of Medicine
Author Masanori Emoto Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine
[ Summary ] Vascular calcification (VC) is the ectopic accumulation of calcium phosphate salts in the arterial wall and is associated with adverse cardiovascular events. Two types of VC have been described: intimal and medial calcification. Intimal calcification develops as a consequence of atherosclerosis and may contribute to plaque rupture, leading to coronary ischemic events. On the other hand, medial calcification is nonatherosclerotic and preferentially occurs along elastic fibers. Consequently, medial calcification increases arterial stiffness, systolic blood pressure, and pulse pressure, resulting in left ventricular hypertrophy, diastolic dysfunction, and cardiac failure. In the development of both types of VC, similar mechanisms may work, such as differentiation of vascular smooth muscle cells into osteoblast-like cells and matrix vesicles-mediated mineralization. However, the promoting factors for intimal and medial calcification may differ; inflammatory factors accelerate intimal calcification, while metabolic factors facilitate medial calcification. In aging, diabetes, and chronic kidney disease, both factors may promote progression of intimal as well as medial calcification.
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