Myosteatosis is the excessive accumulation of fat within skeletal muscle tissue. It's distinct from sarcopenia, which is the age-related loss of muscle mass and strength. Advances in medical imaging have allowed for better detection and study of this condition.
Understanding Myosteatosis
Myosteatosis is characterized by the infiltration of fat into skeletal muscle, impacting its function and overall health. This fat accumulation is considered an ectopic fat depot, meaning it's stored in an unusual location. This infiltration negatively correlates with muscle function.
Several studies highlight the association between myosteatosis and various health issues:
- Aging: Myosteatosis is commonly associated with aging.
- Insulin Resistance and Type 2 Diabetes (T2D): It's linked to insulin resistance and is a significant factor in T2D.
- Non-alcoholic steatohepatitis (NASH) / Metabolic Associated Fatty Liver Disease (MASLD): Myosteatosis is prevalent even in early stages of MASLD and correlates with disease severity.
- Hypertension: Myosteatosis contributes to increased risk of hypertension through mechanisms such as increased insulin resistance and endothelial dysfunction.
- Major Adverse Cardiovascular Events and Death: Higher levels of myosteatosis are associated with increased risk of major adverse cardiac events and mortality.
- Sarcopenia: While distinct, myosteatosis is closely linked to sarcopenia and worsens outcomes in patients, particularly those with cirrhosis.
Increased myosteatosis leads to changes in muscle fiber orientation, negatively affecting muscle strength. It essentially reduces the muscle's efficiency. A simplified explanation compares it to fatty liver disease, where excess calories are stored in an inappropriate location.
Diagnostic Considerations
The precise diagnosis of myosteatosis relies on advanced imaging techniques, allowing for the quantification of muscle fat infiltration. This makes it a measurable biomarker for various health conditions and aging processes.
