Lipofusiini

Lipofuscin is a granular intracellular aggregate material that accumulates in various tissues, particularly in postmitotic cells like neurons and cardiomyocytes, as well as in organs such as the liver and eyes. It is often referred to as a "wear-and-tear" pigment because its accumulation generally increases with age. The exact composition of lipofuscin is complex and varies depending on the cell type and age of the individual, but it primarily consists of oxidized lipids and proteins. It is also associated with lysosomal degradation products that have not been fully broken down.

The formation of lipofuscin is thought to arise from oxidative stress and inefficient cellular repair mechanisms. When cellular components, such as proteins and lipids, undergo damage from reactive oxygen species, they can become modified and resistant to further degradation. These modified molecules are then sequestered within lysosomes, and over time, their accumulation forms visible lipofuscin granules. While once considered inert waste material, current research suggests that lipofuscin may play a more active role in cellular function and dysfunction.

In some contexts, high levels of lipofuscin have been linked to age-related diseases and cellular senescence. For instance, lipofuscin accumulation in retinal pigment epithelial cells is a hallmark of age-related macular degeneration. In the brain, increased lipofuscin in neurons has been observed in neurodegenerative conditions such as Alzheimer's and Parkinson's diseases, although its direct causal role is still debated. Research continues to investigate the precise mechanisms of lipofuscin formation, its impact on cellular health, and potential strategies to mitigate its accumulation.