What question did this study set out to answer?

To biochemically quantify alterations and enzymatic degradation within the myocardial collagen matrix following repeated episodes of brief ischemia and reperfusion.

April 1, 1992CirculationOpen Access

Collagen loss in the stunned myocardium.

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Why the study?

Does ischemia-reperfusion injury causing stunned myocardium alter the collagen matrix in mongrel dogs?

Population

13 mongrel dogs

Comparison

Stunned myocardium produced by a series of 12… vs Normal zone tissue (control)

Design

Preclinical

Follow-up

90 minutes (final reperfusion)

Authors

RCRichard CharneyNew York Medical College STShizuko TakahashiBunkyo University MZMan ZhaoTongji University

Discussion

Member takes

Implication

May link stunning to matrix degradation in dogs; leaves open role in human postischemic remodeling.

Key Points

To biochemically quantify alterations and enzymatic degradation within the myocardial collagen matrix following repeated episodes of brief ischemia and reperfusion.
Induced myocardial stunning in mongrel dogs (N=13) through 12 cycles of 5-minute coronary artery occlusions and 10-minute reperfusions, ending with a 90-minute reperfusion period.
Evaluated regional systolic function, end-diastolic length, transmural hydroxyproline content, collagenase activity, lysosomal proteases, and dansyl chloride fiber labeling.
Transmural collagen content decreased by 12.5% in the midwall (p < 0.05) and 14.6% in the epicardium (p < 0.005), alongside an 8% increase in end-diastolic length and a drop in systolic function to 17% of control.
Endogenous collagenase activity prior to procollagenase activation rose by an average of 73.6% (p < 0.025) across all layers, with stunned fibers showing 9% greater dansyl labeling indicating increased cleavage.
Fully activated collagenase levels, elastase, and cathepsin G showed no significant differences between stunned and normal myocardium, ruling out exogenous leukocyte proteases.

Structured PICO

Does ischemia-reperfusion injury causing stunned myocardium alter the collagen matrix in mongrel dogs?

Population

13 mongrel dogs

Intervention

Stunned myocardium produced by a series of 12 coronary artery occlusions of 5 minutes followed by 10-minute reperfusion periods, with a final reperfusion period of 90 minutes

Comparator

Normal zone tissue (control)

Outcome

Biochemical assessment and quantification of ultrastructural alterations in the collagen matrix (hydroxyproline, collagenase activity, lysosomal enzymes, tissue water content)surrogate

Ischemia-induced activation of endogenous procollagenase leads to extracellular matrix degradation in stunned myocardium, which may contribute to ischemic enlargement of the heart.

Cite This Study

Charney et al. (1992) studied this question.

synapsesocial.com/papers/6a1f87da8b2921da63cf33a7 https://doi.org/10.1161/01.cir.85.4.1483

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Collagen loss in the stunned myocardium.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Collagen loss in the stunned myocardium.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider