Background <p>Skeletal muscle atrophy is a common complication of heart failure, with myocardial infarction (MI) being the primary cause. Yet, the mechanisms linking post-MI cardiac insufficiency to muscle atrophy have remained unclear. The molecular basis for the beneficial effects of exercise on exercise intolerance in MI patients also remains absent.</p> Methods <p>Serum IL-27 levels were measured in 48 MI patients and correlated with cardiac injury markers. Along with this, a rat model of post-MI cardiac insufficiency was used to assess skeletal muscle mass, cross-sectional area (CSA) of muscle fibers, and the expression of atrophy-related (MAFbx, MuRF-1) and differentiation-related markers (MyoD, Myogenin). The impact of exercise on muscle atrophy, cardiac inflammation, and IL-27 expression was then evaluated, with a focus on macrophage polarization. <i>In vitro</i>, the effects of macrophage-derived IL-27 on L6 myotube metabolism were assessed, and the role of HIF-1α in macrophage-derived IL-27 secretion was examined using co-culture systems.</p> Results <p>Serum IL-27 level was significantly elevated in MI patients and that it was positively correlated with myocardial injury and cardiac insufficiency. In post-MI rats, skeletal muscle mass and CSA of muscle fibers were reduced. Meanwhile, the expression level of myogenic markers was downregulated, while that atrophy markers was upregulated. IL-27 treatment promoted catabolism in L6 myotubes, and of note, HIF-1α overexpression in macrophages enhanced IL-27 secretion, and increased MAFbx and MuRF-1 expression. IL-27 level was also elevated in the heart, serum, and gastrocnemius muscle of MI rats. Exercise counteracted these effects by promoting M2-like macrophage polarization and suppressing HIF-1α, thereby reducing IL-27 expression. Furthermore, exercise ameliorated IL-27-induced muscle atrophy via the WSX-1/gp130/pSTAT3 signaling axis.</p> Conclusion <p>IL-27 contributes to muscle atrophy in post-MI cardiac insufficiency. Exercise attenuates IL-27-driven muscle wasting by modulating inflammation and promoting M2-like macrophage polarization. These findings provide insights into the mechanisms of MI-induced muscle atrophy and highlight the therapeutic potential of exercise in cardiac rehabilitation.</p> Graphical Abstract <p></p>

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Exercise mitigates IL-27-induced muscle atrophy following myocardial infarction through anti-inflammatory mechanisms

  • Yuancong Li,
  • Gaosheng Yin,
  • Shuangxiu Li,
  • Qi Zheng,
  • Yongliang Jiang,
  • Changyan Li,
  • Lin Yang,
  • Hao Li,
  • Xingyu Chen,
  • Ping Yang,
  • Lin Sun

摘要

Background

Skeletal muscle atrophy is a common complication of heart failure, with myocardial infarction (MI) being the primary cause. Yet, the mechanisms linking post-MI cardiac insufficiency to muscle atrophy have remained unclear. The molecular basis for the beneficial effects of exercise on exercise intolerance in MI patients also remains absent.

Methods

Serum IL-27 levels were measured in 48 MI patients and correlated with cardiac injury markers. Along with this, a rat model of post-MI cardiac insufficiency was used to assess skeletal muscle mass, cross-sectional area (CSA) of muscle fibers, and the expression of atrophy-related (MAFbx, MuRF-1) and differentiation-related markers (MyoD, Myogenin). The impact of exercise on muscle atrophy, cardiac inflammation, and IL-27 expression was then evaluated, with a focus on macrophage polarization. In vitro, the effects of macrophage-derived IL-27 on L6 myotube metabolism were assessed, and the role of HIF-1α in macrophage-derived IL-27 secretion was examined using co-culture systems.

Results

Serum IL-27 level was significantly elevated in MI patients and that it was positively correlated with myocardial injury and cardiac insufficiency. In post-MI rats, skeletal muscle mass and CSA of muscle fibers were reduced. Meanwhile, the expression level of myogenic markers was downregulated, while that atrophy markers was upregulated. IL-27 treatment promoted catabolism in L6 myotubes, and of note, HIF-1α overexpression in macrophages enhanced IL-27 secretion, and increased MAFbx and MuRF-1 expression. IL-27 level was also elevated in the heart, serum, and gastrocnemius muscle of MI rats. Exercise counteracted these effects by promoting M2-like macrophage polarization and suppressing HIF-1α, thereby reducing IL-27 expression. Furthermore, exercise ameliorated IL-27-induced muscle atrophy via the WSX-1/gp130/pSTAT3 signaling axis.

Conclusion

IL-27 contributes to muscle atrophy in post-MI cardiac insufficiency. Exercise attenuates IL-27-driven muscle wasting by modulating inflammation and promoting M2-like macrophage polarization. These findings provide insights into the mechanisms of MI-induced muscle atrophy and highlight the therapeutic potential of exercise in cardiac rehabilitation.

Graphical Abstract