What is "lipocartilage"?
The majority of cartilage is strengthened by an external extracellular matrix, but "lipocartilage," which is found in mammals' ears, nose, and throat is special because it is packed with fat-filled cells known as "lipochondrocytes" that give the tissue extremely stable internal support, keeping it soft and springy like bubble packaging material.
The research published in the journal Science on January 9, 2025, explains how lipocartilage cells produce and preserve their own lipid reservoirs while maintaining a consistent size. Lipochondrocytes, in contrast to regular adipocyte fat cells, do not contract or enlarge in reaction to the availability of food.
“Lipocartilage’s resilience and stability provide a compliant, elastic quality that’s perfect for flexible body parts such as earlobes or the tip of the nose, opening exciting possibilities in regenerative medicine and tissue engineering, particularly for facial defects or injuries,” said corresponding author Maksim Plikus, UC Irvine professor of developmental and cell biology. “Currently, cartilage reconstruction often requires harvesting tissue from the patient’s rib – a painful and invasive procedure. In the future, patient-specific lipochondrocytes could be derived from stem cells, purified and used to manufacture living cartilage tailored to individual needs. With the help of 3D printing, these engineered tissues could be shaped to fit precisely, offering new solutions for treating birth defects, trauma and various cartilage diseases.”
Lipochondrocytes were first identified by Dr. Franz Leydig in 1854 when he discovered fat droplets in rat ear cartilage, a finding that was largely forgotten until now.
Researchers from UC Irvine thoroughly characterised the molecular biology, metabolism, and structural function of lipocartilage in skeletal tissues utilising advanced imaging techniques and modern biochemical tools.
They also discovered the genetic mechanism that essentially locks down the lipid stores in lipochondrocytes by inhibiting the action of enzymes that break down lipids and lowering the absorption of new fat molecules. The lipocartilage becomes brittle and stiff when its lipids are removed, underscoring the role that its fat-filled cells play in preserving the tissue's ability to be both flexible and durable. Furthermore, the study observed that lipochondrocytes in certain species, like bats, form complex structures, such as parallel ridges in their large ears, which could enhance hearing acuity by modulating sound waves.
Journal: 10.1126/science.ads9960
(Newswise/SD)