Hypertrophe

Hypertrophe, or hypertrophy in English, refers to the enlargement of an organ or tissue caused by an increase in the size of its cells rather than a rise in the number of cells. It is a descriptive term used across medical disciplines to describe adaptive or maladaptive growth in a variety of tissues.

Hypertrophy can be classified as physiologic or pathologic. Physiologic hypertrophy occurs as a normal response to stimuli, such as resistance training leading to larger skeletal muscle fibers, or endurance adaptations in the heart that are generally considered benign. Pathologic hypertrophy arises from disease processes, most commonly chronic pressure or volume overload (for example, systemic hypertension or aortic stenosis in the heart) and can progress to impaired function if the process becomes maladaptive.

Cellular and molecular mechanisms involve signaling pathways that promote protein synthesis and growth of the cell. Mechanical stress activates pathways such as IGF-1/Akt/mTOR and others that increase cellular size and sometimes alter gene expression. In the heart, hypertrophy can be accompanied by changes in myocyte structure and, over time, fibrosis or impaired contractility, reflecting a shift from adaptive to maladaptive remodeling.

Diagnosis typically relies on imaging techniques, including echocardiography or MRI, to measure tissue thickness and organ size. Histological examination, when available, shows enlarged cells and can reveal architectural changes. Management focuses on addressing the underlying cause, limiting maladaptive remodeling, and monitoring organ function; treatment differs by context and may range from lifestyle modification to medical or surgical interventions.

Hypertrophy differs from hyperplasia, which is an increase in tissue size due to more cells rather than larger cells.