Friction in Myocardial Anoxia Leads to Negative Excess Entropy Production, Self-Organization, and Dissipative Structures

Figures

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  Figure 1. Schematic representations of myofilaments in sarcomeric heart muscle and tribological cardiac system. Cardiomyocytes exhibit a periodic striation characterized by alternating dark A-bands (anisotropic) and light I-bands (isotropic) (A,B). The central part of the I-band is marked by the Z line. A sarcomere is the smallest functional unit of a striated muscle. It is the repeating unit between two Z-lines (B). The I-band is the zone of thin filaments that is not superimposed with thick filaments (myosin). Thin myofilaments are mainly composed of F actin, resulting from the polymerization of many globular actin molecules (G actin). The actin myofilaments are attached by their caudal end to the Z lines. Actin filaments are the major component of the I-band and extend into the A-band. Thick myosin filaments are made up of 200 to 300 molecules of native myosin. Myosin has a long, fibrous tail and a globular head that binds to actin. Myosin filaments are bipolar and extend throughout the A-band. The myosin head also binds to ATP. Muscle contraction results in the sliding of actin filaments along myosin filaments, which is visible only at the level of the I-bands, while the dark A-bands…

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  Figure 2. Mechanical parameters of LVPMs and CBs. (A): Maximum unloaded shortening velocity (Vmax); (B): CB single force (po); (C): total muscle tension; (D): myosin content. *: p < 0.05; ***: p < 0.001.

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  Figure 3. Molecular parameters of CBs. (A): CB detachment rate constant (g2); (B): normal load (W); (C): friction coefficient (μ); (D): frictional force (F). ***: p < 0.001.

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  Figure 4. Non-linear thermodynamic force versus thermodynamic flow relationship. The myofilament sliding velocity (vo), or thermodynamic flow, is represented in (A); (B): Mean thermodynamic force versus mean thermodynamic flow; (C): Mean values of thermodynamic force versus thermodynamic flow (vo). ***: p < 0.001; (D): Linear relationship between EEP and the G curvature of the Hill hyperbola: EEP (10−4) = −22 + 2.4 G (10−1); r = 0.99.

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  Figure 5. Mean thermodynamic parameters. (A): Mean thermodynamic flow versus time; (B): mean thermodynamic force versus time; (C): mean thermodynamic flow versus partial time derivative; (D): mean thermodynamic versus partial time derivative.

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  Figure 6. Entropy production rate (EPR) and excess entropy production (EEP). Entropy production rate (EPR) (in mN · μm · s−1 · T−1) versus time is represented in (A). (B) presented excess entropy production (EEP) (in mN · μm · s−2 · T−1 versus time. Note that EEP became negative from 150 to 180 min of anoxia. (C) showed the linear relationship between mean EEP and mean max. Efficiency (EEP = 1.9 max. Efficiency-3 7) (r = 0.90). EEP became negative when max. Efficiency was <19%.