In a significant scientific breakthrough, an international research team led by the University of California, Irvine (UCI) has uncovered a new type of skeletal tissue that promises to advance the fields of regenerative medicine and tissue engineering.
The newly identified tissue, named "lipocartilage," is composed of fat-filled cells called "lipochondrocytes" that provide internal stability and remain constant in size, regardless of food availability.
"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," corresponding author Maksim Plikus, a UC Irvine professor of developmental and cell biology, said in a news release.
Unlike traditional cartilage, which relies on an external extracellular matrix for strength, lipocartilage stays soft and springy thanks to its unique cellular makeup, akin to bubbled packaging material.
This innovative tissue could potentially eliminate the need for painful and invasive procedures, such as harvesting cartilage from a patient's rib for reconstructive purposes.
"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," Plikus added.
The discovery also sheds light on the sophisticated mechanisms behind lipocartilage's formation and maintenance.
The research, published in the journal Science. revealed that lipocartilage cells create and manage their own lipid reservoirs, maintaining their size and providing essential support to the tissue. When these lipids are removed, the tissue becomes brittle, underscoring the crucial role of lipochondrocytes.
Lead author Raul Ramos, a postdoctoral researcher in Plikus's lab, highlighted the groundbreaking nature of the findings.
"The discovery of the unique lipid biology of lipocartilage challenges long-standing assumptions in biomechanics and opens doors to countless research opportunities," he said in the news release.
Franz Leydig first identified the presence of fat droplets in the cartilage of rat ears in 1854, an observation that was largely forgotten until now. With current advanced biochemical tools and imaging methods, the researchers were able to explore lipocartilage's molecular biology, metabolism and structural role in-depth.
The presence of lipochondrocytes in various mammals, with some like bats forming intricate shapes in their oversized ears to enhance hearing, opens pathways for further research in understanding the stability and genetic processes governing these cells.
"Future directions include gaining an understanding of how lipochondrocytes maintain their stability over time and the molecular programs that govern their form and function, as well as insights into the mechanisms of cellular aging," added Ramos. "Our findings underscore the versatility of lipids beyond metabolism and suggest new ways to harness their properties in tissue engineering and medicine."