title: Diabetes mellitus aggravates hemorrhagic transformation after ischemic stroke via mitochondrial defects leading to endothelial apoptosis.
abstract: Diabetes is a crucial risk factor for stroke and is associated with increased frequency and poor prognosis. Although endothelial dysfunction is a known contributor of stroke, the underlying mechanisms have not been elucidated. The aim of this study was to elucidate the mechanism by which chronic hyperglycemia may contribute to the worsened prognosis following stroke, especially focusing on mitochondrial alterations. We examined the effect of hyperglycemia on hemorrhagic transformation at 24 hours after middle cerebral artery occlusion (MCAO) in streptozotocin (STZ) -induced diabetic mice. We also examined the effects of high-glucose exposure for 6 days on cell death, mitochondrial functions and morphology in human brain microvascular endothelial cells (HBMVECs) or human endothelial cells derived from induced pluripotent stem cells (iCell endothelial cells). Hyperglycemia aggravated hemorrhagic transformation, but not infarction following stroke. High-glucose exposure increased apoptosis, capase-3 activity, and release of apoptosis inducing factor (AIF) and cytochrome c in HBMVECs as well as affected mitochondrial functions (decreased cell proliferation, ATP contents, mitochondrial membrane potential, and increased matrix metalloproteinase (MMP)-9 activity, but not reactive oxygen species production). Furthermore, morphological aberration of mitochondria was observed in diabetic cells (a great deal of fragmentation, vacuolation, and cristae disruption). A similar phenomena were seen also in iCell endothelial cells. In conclusion, chronic hyperglycemia aggravated hemorrhagic transformation after stroke through mitochondrial dysfunction and morphological alteration, partially via MMP-9 activation, leading to caspase-dependent apoptosis of endothelial cells of diabetic mice. Mitochondria-targeting therapy may be a clinically innovative therapeutic strategy for diabetic complications in the future.
authors.affiliation: Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Mishiro
authors.affiliation: Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Imai
authors.affiliation: Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan.
authors.forename: Sou
authors.initials: S
authors.lastname: Sugitani
authors.affiliation: Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kitashoji
authors.affiliation: Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan.
authors.forename: Yukiya
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan; Departments of Neurosurgery, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Takagi
authors.affiliation: Department of Anatomy, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Huayue
authors.initials: H
authors.lastname: Chen
authors.affiliation: Division of Instrument Analysis, Life Science Research Center, Gifu University, Gifu, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Oumi
authors.affiliation: Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tsuruma
authors.affiliation: Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Shimazawa
authors.affiliation: Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Hara
mesh_terms: D000818:Animals; D017209:Apoptosis; D002545:Brain Ischemia / Q000473:pathology*; D002478:Cells, Cultured; D002543:Cerebral Hemorrhage / Q000473:pathology*; D003921:Diabetes Mellitus, Experimental / Q000150:complications*; D042783:Endothelial Cells / Q000502:physiology*; D004730:Endothelium, Vascular / Q000473:pathology; D005947:Glucose / Q000502:physiology; D006801:Humans; D006943:Hyperglycemia / Q000150:complications; D008297:Male; D053078:Membrane Potential, Mitochondrial; D051379:Mice; D008928:Mitochondria / Q000378:metabolism / Q000473:pathology; D053140:Organelle Shape; D011379:Prognosis
chemical_list: D005947:Glucose