Professor Kelvin Yeung is a renowned expert in orthopaedic biomaterial research, with a primary focus on the design of orthopaedic biomaterials, antibacterial nano-materials, 3D bio-printing, and musculoskeletal tissue engineering. He obtained his bachelor's degree in materials science and further pursued a master's degree and PhD in orthopaedic science at the University of Hong Kong's Medical Faculty. Over the years, he has concentrated on bone-to-implant osseointegration, bone regeneration, and antibacterial treatments.

Currently, Professor Yeung serves as a tenured full professor, chief of the research division, and departmental research and postgraduate advisor in the Department of Orthopaedics and Traumatology, School of Clinical Medicine, LKS Faculty of Medicine (HKUMed), at The University of Hong Kong. His impressive h-index (Scopus) is 78, with over 20,000 citations and 85 (Google Scholar) with 24,000+ citations and an i10-index of 255. He has been recognized as one of the Highly Cited Researchers 2023 (cross-field), ranking among the Top 1% Scholars Worldwide in the field of biomaterials by Clarivate Analytics' Essential Science Indicators (ESI) and among the World's Top 2% Scientists in standardized citation indicators (Biomedical Engineering) since 2014. In 2023, he ranked #1926 globally and #486 in China under the category of materials science (Research.com). Beyond his extensive publication record, which includes over 290 peer-reviewed SCI journal papers and 41 filed full patents in various countries, Professor Yeung co-founded OrthoSmart Limited with two senior colleagues to translate their research findings into clinical applications. He also serves as a consultant for several Hong Kong-listed medical and biomaterials corporations.

Active in local and international academic bodies, Professor Yeung has held several executive positions. He is the Associate Editor of Bioactive Materials Journal (Impact factor (2022): 18.9, Ranking: 1/45 in materials science (Biomaterials)), Secretary and founding member of the Chinese Association for Biomaterials (CAB), Chair of Orthopaedic Biomaterials for the Society for Biomaterials (SFB) USA, past Treasurer of CAB, and past Vice-Chair of SFB Orthopaedic Biomaterials. Moreover, he has been appointed as the Associate Dean of Student Affairs for the Centre of Development and Resources for Students (CEDARS) by the University, where he oversees the student matters.

Topic title: Multiple cations enriched in bone tissue microenvironment can induce superior bone regeneration mediated by the CNS-skeletal circuit

Abstract:

3D-printed titanium (Ti) scaffolds are the most widely used implantable material for the management of segmental bone defects. However, rapid bone-to-implant osteointegration is rarely occurred after surgery. In this study, we investigated the possibility of enhancing bone regeneration by utilizing a relatively new pathway, namely central nervous system (CNS)-skeletal axis or skeletal interoception. We accomplished this by delivering three bivalent metallic ions (i.e., magnesium, zinc, and copper) into the bone tissue microenvironment under a controlled manner. The combination of these ions was specifically designed to promote in situ intramembranous bone formation, and we also investigated the underlying mechanism.

To evaluate the effectiveness of this approach, we injected alginate hydrogels loaded with these cations into the femoral defect of knock-out mouse models, including iDTRLysM+/− and TrkAfl/fl mice. We assessed new bone formation through micro-CT, mechanical testing, as well as various histological and immunochemical analyses.

Our findings indicate that these cations stimulate skeleton interoception by promoting prostaglandin E2 secretion from macrophages, which triggers an immune response. This response is accompanied by the growth and branching of calcitonin gene-related polypeptide-α+ nerve fibers that detect the inflammatory cue with PGE2 receptor 4 and transmit the interoceptive signals to the central nervous system. Activating skeleton interoception downregulates sympathetic tone, promoting new bone formation. Additionally, either macrophage depletion or knockout of cyclooxygenase-2 in macrophages eliminates divalent cation-induced skeleton interoception. Furthermore, sensory denervation or knockout of EP4 in sensory nerves eliminates the osteogenic effects of divalent cations.

The findings of this study could pave the way for the development of novel biomaterials that harness the therapeutic power of these divalent cations to promote bone regeneration effectively. The study also highlights the importance of the CNS-skeletal axis in bone regeneration and the potential for developing new therapies that target this pathway.