Regenerative medicine is a field of science that aims to heal or replace damaged cells, tissues, and organs for patients who suffer injuries or degenerative disorders. It encompasses tissue engineering, materials science, stem cell biology, and other biomedical disciplines. This field relies on cell-based therapies, biomaterials, and gene therapy to trigger the body’s natural healing process and restore function to organs. However, a groundbreaking discovery by an international group of scientists led by the University of California, Irvine (UCI) promises to improve upon these methods. The team has discovered a skeletal tissue known as lipocartilage, whose properties could change the way we approach tissue regeneration. The results of this study have major healthcare implications for both humans and animals.
Found in mammals’ ears, noses, and throats, lipocartilage differs from normal cartilage by not relying on the extracellular matrix (ECM) for its support and strength. Normal cartilage is made by chondrocytes, which produce the ECM components that give cartilage the mechanical properties necessary to support joints and give structure to noses and ears. Lipocartilage is made of lipochondrocytes (LCs), fat cells that differ from adipose fat. Adipose fat tissue stores the body’s energy, meaning it grows and shrinks in response to caloric intake. LCs are not affected by dietary habits and maintain their size and shape indefinitely. This allows lipocartilage to provide structural support to the earlobes and tip of the nose.
LCs were first discovered in 1854 by German zoologist and comparative anatomist Franz Leydig while he was studying rat ears. His study was the only study on lipocartilage for over a century, as not only was it not studied by other scientists, but those who stumbled upon them in other research “did not study them or the tissue in detail,” writes The Scientist.
The study published in the journal Science details the more than decade-long effort to understand lipocartilage and its methods of metabolism, structure, and function. It started when Dr. Maksim Plikus, professor of Developmental and Cell biology at UCI, was studying the fat cells in rat ear skin. He and his team discovered that some of the fat cells they were observing would not respond to any of the dyes they introduced into the environment. These stubborn fat cells were called LCs. Plikus described LCs as bubbles in bubble wrap. The findings of this study deepen our understanding of skeletal biomechanics and create new opportunities in regenerative medicine. For instance, the researchers have detailed how LCs suppress the activity of enzymes that break down fat for energy use. This maintains their strength and flexibility.
The team of the study included “healthcare professionals and academics from the U.S., Australia, Belarus, Denmark, Germany, Japan, South Korea and Singapore,” writes UCI News. The animals included in this study were courtesy of “Serrano Animal & Bird Hospital in Lake Forest and the Santa Ana Zoo.” Studying mammals gave insight into how LCs can be molded to provide certain advantages. In bats, it was found that LCs in the ear help to modulate sound waves, increasing the acuity of their hearing. Having found other evolutionary advantages of lipocartilage-composed structures, researchers have gained insights into the importance of fat cells to the function of skeletal tissue.
Regenerative medicine is a rapidly evolving field whose innovations aim to heal patients without the use of invasive surgical procedures with long healing times. The findings of this study can help in the evolution of the field. Using stem cells to produce LCs and tissue engineering techniques allows us to develop scaffold structures for regenerating damaged cartilage in arthritic patients and those who suffer from other cartilage-degenerative diseases. Current solutions involve extracting cartilage from patients’ ribs, which is invasive and painful. Dr. Plinkus told UCI News, “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.” Similar techniques can be used to treat other mammals that depend on cartilage structures.
The findings of this study not only provide a new understanding of LCs but also open the door for less invasive treatments, genetically tailored treatments for humans and animals, which improve patient outcomes. By uncovering the unique properties of skeletal tissue, scientists are developing new organs that mimic the body’s environment more closely than before.
