Increased propensity for cell death in diabetic human heart is mediated by mitochondrial-dependent pathways

Ethan J. Anderson, Evelio Rodriguez, Curtis A. Anderson, Kathleen Thayne, W. Randolph Chitwood, Alan P. Kypson

    Research output: Contribution to journalArticle

    58 Citations (Scopus)

    Abstract

    Progressive energy deficiency and loss of cardiomyocyte numbers are two prominent factors that lead to heart failure in experimental models. Signals that mediate cardiomyocyte cell death have been suggested to come from both extrinsic (e.g., cytokines) and intrinsic (e.g., mitochondria) sources, but the evidence supporting these mechanisms remains unclear, and virtually nonexistent in humans. In this study, we investigated the sensitivity of the mitochondrial permeability transition pore (mPTP) to calcium (Ca2+) using permeabilized myofibers of right atrium obtained from diabetic (n = 9) and nondiabetic (n = 12) patients with coronary artery disease undergoing nonemergent coronary revascularization surgery. Under conditions that mimic the energetic state of the heart in vivo (pyruvate, glutamate, malate, and 100 μM ADP), cardiac mitochondria from diabetic patients show an increased sensitivity to Ca2+-induced mPTP opening compared with nondiabetic patients. This increased mPTP Ca2+ sensitivity in diabetic heart mitochondria is accompanied by a substantially greater rate of mitochondrial H 2O2 emission under identical conditions, despite no differences in respiratory capacity under these conditions or mitochondrial enzyme content. Activity of the intrinsic apoptosis pathway mediator caspase-9 was greater in diabetic atrial tissue, whereas activity of the extrinsic pathway mediator caspase-8 was unchanged between groups. Furthermore, caspase-3 activity was not significantly increased in diabetic atrial tissue. These data collectively suggest that the myocardium in diabetic patients has a greater overall propensity for mitochondrial-dependent cell death, possibly as a result of metabolic stress-imposed changes that have occurred within the mitochondria, rendering them more susceptible to insults such as Ca2+ overload. In addition, they lend further support to the notion that mitochondria represent a viable target for future therapies directed at ameliorating heart failure and other comorbidities that come with diabetes.

    Original languageEnglish (US)
    JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
    Volume300
    Issue number1
    DOIs
    StatePublished - Jan 1 2011

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    Mitochondria
    Cell Death
    Cardiac Myocytes
    Heart Failure
    Heart Mitochondria
    Physiological Stress
    Caspase 9
    Caspase 8
    Heart Atria
    Pyruvic Acid
    Caspase 3
    Adenosine Diphosphate
    Comorbidity
    Coronary Artery Disease
    Glutamic Acid
    Myocardium
    Theoretical Models
    Apoptosis
    Cytokines
    Calcium

    All Science Journal Classification (ASJC) codes

    • Physiology
    • Cardiology and Cardiovascular Medicine
    • Physiology (medical)

    Cite this

    Increased propensity for cell death in diabetic human heart is mediated by mitochondrial-dependent pathways. / Anderson, Ethan J.; Rodriguez, Evelio; Anderson, Curtis A.; Thayne, Kathleen; Chitwood, W. Randolph; Kypson, Alan P.

    In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 300, No. 1, 01.01.2011.

    Research output: Contribution to journalArticle

    Anderson, Ethan J. ; Rodriguez, Evelio ; Anderson, Curtis A. ; Thayne, Kathleen ; Chitwood, W. Randolph ; Kypson, Alan P. / Increased propensity for cell death in diabetic human heart is mediated by mitochondrial-dependent pathways. In: American Journal of Physiology - Heart and Circulatory Physiology. 2011 ; Vol. 300, No. 1.
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