Cellulaire adaptatie II: Hypertrofie

Hypertrophy refers to an increase in the size of individual cells, leading to the enlargement of tissues or organs to enhance their work capacity.

Physiological hypertrophy is a reversible adaptation that improves tissue function. For example, skeletal muscle hypertrophy develops with consistent resistance training.

Mechanical stress on muscle fibers activates key signaling pathways, including the insulin-like growth factor 1, protein kinase B, also known as Akt, and the mechanistic target of rapamycin pathways.

These signals stimulate protein synthesis, increase the production of contractile proteins, and promote muscle fiber growth. As a result, muscles increase in size and strength.

Pathologic hypertrophy results when cell growth from chronic or abnormal stress impairs organ function.

For example, chronic hypertension may cause cardiac hypertrophy as the heart adapts to pump against increased resistance.

Persistent strain enlarges myocardial cells. Although this initially preserves cardiac function, prolonged hypertrophy can ultimately lead to heart failure.