TY - JOUR
T1 - Increased calcium vulnerability of senescent cardiac mitochondria
T2 - Protective role for a mitochondrial potassium channel opener
AU - Jahangir, Arshad
AU - Ozcan, Cevher
AU - Holmuhamedov, Ekhson L.
AU - Terzic, Andre
N1 - Funding Information:
This work was supported by National Institutes of Health (HL-64822, HL-07111), American Heart Association, Miami Heart Research Institute, the Bruce and Ruth Rappaport Program in Vascular Biology and Gene Delivery, and the Marriott Foundation. AJ is a recipient of a CR20 Award from the Mayo Foundation. AT is an Established Investigator of the American Heart Association.
PY - 2001/7/31
Y1 - 2001/7/31
N2 - In senescence, endogenous mechanisms of cardioprotection are apparently attenuated resulting in increased vulnerability to ischemia-reperfusion. In particular, mitochondria, which are essential in maintaining cardiac energetic and ionic homeostasis, are susceptible to Ca2+ overload, a component of metabolic injury. However, effective means of protecting senescent mitochondria are lacking. Here, mitochondrial function and structure were assessed using ion-selective mini-electrodes, high-performance liquid chromatography and electron microscopy. Aging decreased ADP-induced oxygen consumption and prolonged the time associated with ADP to ATP conversion, which manifested as a reduced rate of oxidative phosphorylation. Aging also reduced mitochondrial Ca2+ handling, and increased Ca2+-induced mitochondrial damage. Diazoxide, a potassium channel opener, reduced Ca2+ loading and protected the functional and structural integrity of senescent mitochondria from Ca2+-induced injury. In this way, the present study identifies the potential usefulness for pharmacotherapy in protecting vulnerable senescent mitochondria from conditions of Ca2+ overload, such as ischemia-reperfusion.
AB - In senescence, endogenous mechanisms of cardioprotection are apparently attenuated resulting in increased vulnerability to ischemia-reperfusion. In particular, mitochondria, which are essential in maintaining cardiac energetic and ionic homeostasis, are susceptible to Ca2+ overload, a component of metabolic injury. However, effective means of protecting senescent mitochondria are lacking. Here, mitochondrial function and structure were assessed using ion-selective mini-electrodes, high-performance liquid chromatography and electron microscopy. Aging decreased ADP-induced oxygen consumption and prolonged the time associated with ADP to ATP conversion, which manifested as a reduced rate of oxidative phosphorylation. Aging also reduced mitochondrial Ca2+ handling, and increased Ca2+-induced mitochondrial damage. Diazoxide, a potassium channel opener, reduced Ca2+ loading and protected the functional and structural integrity of senescent mitochondria from Ca2+-induced injury. In this way, the present study identifies the potential usefulness for pharmacotherapy in protecting vulnerable senescent mitochondria from conditions of Ca2+ overload, such as ischemia-reperfusion.
KW - Aging
KW - Calcium
KW - Cardioprotection
KW - Diazoxide
KW - K-ATP channel
KW - Senescence
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U2 - 10.1016/S0047-6374(01)00242-1
DO - 10.1016/S0047-6374(01)00242-1
M3 - Article
C2 - 11389925
AN - SCOPUS:0035979490
SN - 0047-6374
VL - 122
SP - 1073
EP - 1086
JO - Mechanisms of Ageing and Development
JF - Mechanisms of Ageing and Development
IS - 10
ER -