Lin Han, Ph.D. – 2021 Kappa Delta Young Investigator Winner

Lin Han, Ph.D., associate professor in the School of Biomedical Engineering, Science and Health Systems at Drexel University in Philadelphia, has been honored with the 2021 Kappa Delta Young Investigator Award from the American Academy of Orthopaedic Surgeons (AAOS) for his revealing work that advances cartilage regeneration and disease intervention.

While the cartilage breakdown that occurs in osteoarthritis (OA) is devastating, it may be no match for the inquisitive mind of Dr. Lin Han.

“Cartilage is one of the simplest tissues in the human body, yet the more we discover, the more we become aware of the unknowns,” said Dr. Han.

When OTW asked his opinion on why the field still lacks a way to fully restore the function of native cartilage, Dr. Lin explained, “This is because we still do not understand how the cartilage is formed and matured in its native form, i.e., what molecules drive the assembly of cartilage in vivo, and how. This makes our study important: in it we find new roles of decorin in regulating the integrity of cartilage (more specifically, the integrity of aggrecan molecules in cartilage).”

“We found that decorin, a small proteoglycan, increases the integrity and retention of aggrecan, the major constituent of cartilage extracellular matrix responsible for tissue biomechanical functions. In osteoarthritis, increase of decorin content inhibits the loss of aggrecan from the degrading ECM, and thus, delays the breakdown of cartilage.”

Using tools based on atomic force microscopy (AFM), Dr. Lin and his colleagues dug into the nuances of aggrecan under different loading modalities, including compression, shear, adhesion, and dynamic oscillatory loading.

This, said Dr. Han, brought forth the revelation that “aggrecan can undergo self-adhesion under physiological conditions.”

Aggrecan, Dr. Han explained, “Is a major cartilage biomacromolecule that has a ‘bottle-brush’ like structure with large amounts of negative charges. Under physiological conditions, aggrecan is highly compressed, and can adhere to adjacent aggrecan molecules. Such interactions increase the retention and help the maintenance of aggrecan inside cartilage.”

It is most important to know, said Dr. Han, that “decorin is an essential constituent of cartilage and modulating decorin activities can have the potential to improve cartilage regeneration.”