Vetdruppels

Vetdruppels, or lipid droplets, are intracellular organelles that store neutral lipids, principally triglycerides and cholesteryl esters. They are found in nearly all eukaryotic cells, but are especially abundant in adipocytes and liver cells, where they function as a major energy reserve. Vetdruppels consist of a hydrophobic core of lipids surrounded by a phospholipid monolayer and a surface coat of proteins, including members of the PAT family such as perilipins, which regulate access to the stored lipids. Lipid droplets originate from the endoplasmic reticulum, grow by accumulating lipids, and can be mobilized by lipases to release fatty acids that fuel metabolism or biosynthesis.

Biogenesis and dynamics: They are dynamic organelles that respond to nutritional and hormonal cues. Growth occurs by lipid deposition and fusion, while lipolysis releases fatty acids through enzymes such as ATGL and HSL, often coordinated with cellular energy demand.

Functions and significance: Primary energy storage, participation in lipid homeostasis, and provision of lipids for membrane synthesis and signaling. They also help sequester potentially toxic lipid species, reducing lipotoxic stress.

Occurrence: Lipid droplets are widespread across life; in plants, oil bodies in seeds serve a similar storage role, while animal cells contain numerous smaller droplets in many tissues.

Clinical relevance: Dysregulation of lipid droplets is linked to obesity, fatty liver disease, insulin resistance, and lipodystrophy, and it influences metabolic health and disease progression.

Research and terminology: Vetdruppels are studied with imaging of droplet-associated proteins, lipid staining, and genetic manipulation of PAT proteins to understand droplet dynamics and metabolism.