Chronic Heart Failure Has an Unexpected Effect on Your Muscles

Chronic heart failure presents a tough challenge, not only because of its impact on the heart but also due to the changes it causes in skeletal muscles, which can affect a person’s overall health. A significant study conducted by Dr. Sofia Gitler, Ibrahim Ramirez-Soto, Professor Aura Jiménez-Garduño, and Professor Alicia Ortega from the Universidad Nacional Autónoma de México provides new perspectives on how muscles adapt to this condition. The findings, published in the International Journal of Molecular Sciences, highlight the biological adjustments that help preserve muscle function during prolonged heart stress.

“Difficulty with physical activity and muscle weakness are common symptoms of chronic heart failure,” explained Dr. Gitler. However, the study uncovers surprising resilience in muscle performance, offering potential new paths for treatment.

Dr. Gitler et al. explored the details of muscle cell behavior using a rat model of chronic heart failure created through a surgical procedure. A rat model is an experimental system using rats to mimic human diseases for research. Three months after inducing heart failure with extensive myocardial infarction, the team observed remarkable chemical changes in specific parts of the skeletal muscle cells. “The increased activity of proteins that manage calcium and glucose in muscle cells appears to provide protection against energy loss and fatigue,” noted Dr. Gitler et al. Calcium is essential for muscle contraction, while glucose serves as a primary energy source. These changes were profound—activity of calcium-regulating proteins increased fivefold, while glucose transport proteins rose sevenfold compared to unaffected rats.

One of the most notable findings was that the mechanical properties of the muscles, such as their ability to contract and recover from fatigue, remained unaffected by chronic heart failure. Mechanical properties refer to how muscles perform physical tasks, including generating force and enduring strain. This discovery challenges long-held beliefs about inevitable muscle deterioration and suggests that the body has built-in ways to counteract these effects at a cellular level.

Dr. Gitler and colleagues highlighted the role of nitric oxide, a molecule known for improving blood flow. Blood flow ensures that muscles receive enough oxygen and nutrients to function. Its levels were higher in rats with chronic heart failure, which may help maintain proper circulation and muscle function. “This could explain why muscle strength was preserved despite the widespread effects of heart failure,” said Dr. Gitler.

Moreover, the study drew attention to the glucose transport protein, which responds to insulin to support energy supply in muscles. Insulin is a hormone that helps regulate blood sugar levels. The increased levels of this protein help the muscles access energy during prolonged activity. Similarly, the enhanced activity of calcium-regulating proteins prevents dangerous calcium buildup in the cells, protecting them from damage.

Looking at the broader implications, the researchers believe that understanding these natural adaptations could lead to better treatments. Treatments could involve enhancing the body’s ability to regulate energy and calcium in muscles. Methods that boost glucose transport or calcium-regulating proteins might help people suffering from muscle fatigue or weakness caused by chronic conditions.

Although the findings are promising, Dr. Gitler and colleagues emphasize the need for further studies to see if these mechanisms also apply to humans and how they could be targeted through treatments. This research provides a deeper understanding of how chronic illnesses affect muscles and offers hope for developing effective interventions to improve patient outcomes.