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Updated: May 13, 2026
In Vitro Assessment of Cardiac Function Using Skinned Cardiomyocytes
Published on: June 22, 2020
Isolated hearts treated with skeletal muscle homogenates exhibit altered function
Alex P Di Battista1, Marius Locke
1Faculty of Kinesiology and Physical Education, University of Toronto, 55 Harbord Street, Toronto, Ontario, M5S 2W6, Canada.
Abstract:
Skeletal muscle fiber damage and necrosis can result in the release of intracellular molecules into the extracellular environment. These molecules, termed damage-associated molecular patterns (DAMPs), can act as signals capable of initiating immune and/or inflammatory responses through interactions with pattern recognition receptors. To investigate whether skeletal muscle DAMPs interact with the heart and alter cardiac function, isolated rat hearts were perfused for 75 min with buffer containing 1 μg/ml of either soleus (slow), white gastrocnemius (WG, fast), or heat-stressed white gastrocnemius (HSWG) skeletal muscle homogenates. Left ventricular developed pressure (LVDP) and rates of pressure increase/decrease (± dP/dt) were measured using the Langendorff technique. Compared to controls, no changes in LVDP or +dP/dt were observed over the 75-min perfusion when homogenates from the WG muscles were added. In contrast, at 30 min and thereafter, a decreased LVDP and +dP/dt was observed in the hearts treated with soleus muscle homogenates. The hearts treated with HSWG homogenates also showed a decrease in LVDP from 45 min until the end of perfusion. These results suggest that molecules present in slow muscle and heat-stressed muscle are capable of altering cardiac function. Thus, muscle fiber type and/or heat shock protein content of skeletal muscles may be factors that influence cardiac function following skeletal muscle damage.
Insights
Skeletal muscle damage releases molecules that can affect heart function. Slow-twitch and heat-stressed muscle homogenates impaired cardiac pressure, suggesting fiber type influences heart health after injury.
Area of Science:
- Physiology
- Immunology
- Cardiology
Background:
- Skeletal muscle damage releases intracellular molecules, known as damage-associated molecular patterns (DAMPs).
- DAMPs can initiate immune and inflammatory responses by interacting with pattern recognition receptors.
- The impact of skeletal muscle DAMPs on cardiac function remains largely unexplored.
Purpose of the Study:
- To investigate whether DAMPs from different skeletal muscle types and conditions alter cardiac function.
- To determine if slow-twitch vs. fast-twitch muscle homogenates differentially affect heart performance.
- To assess the role of heat stress in skeletal muscle DAMPs' effect on the heart.
Main Methods:
- Isolated rat hearts were perfused using the Langendorff technique for 75 minutes.
- Perfusion buffers contained homogenates from soleus (slow), white gastrocnemius (WG, fast), or heat-stressed white gastrocnemius (HSWG) skeletal muscles.
- Cardiac function was assessed by measuring left ventricular developed pressure (LVDP) and ±dP/dt.
Main Results:
- Homogenates from white gastrocnemius (fast-twitch) muscles did not alter cardiac function.
- Soleus (slow-twitch) muscle homogenates significantly decreased LVDP and +dP/dt from 30 minutes onwards.
- Heat-stressed white gastrocnemius (HSWG) homogenates reduced LVDP from 45 minutes to the end of perfusion.
Conclusions:
- Molecules released from slow-twitch and heat-stressed skeletal muscles can negatively impact cardiac function.
- Skeletal muscle fiber type and heat shock protein content may influence cardiac responses to muscle damage.
- These findings highlight a potential link between skeletal muscle injury and cardiac dysfunction.
