Josh Karam: The Angiogenic Role of Hyauluronic Acid Molecular Weight in Biomaterials for Spinal Cord Repair

SEMINAR (Zoom)

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Speaker

Josh Karam

9:00 am via ZOOM

Title: The Angiogenic Role of Hyaluronic Acid Molecular Weight in Biomaterials for Spinal Cord Repair

Abstract

There are currently no treatments that can fully restore function and regenerate tissue after spinal
cord injury (SCI). This is due to the complex pathophysiology of SCI which presents several
barriers to functional repair such as chronic inflammation and glial scar formation. The injury
also induces enzymatic degradation of the spinal cord extracellular matrix (ECM), which is rich
in high molecular weight hyaluronic acid (>300 kDa, HMW HA). Despite its relatively simple
structure, the MW of HA has profound effects on its bioactivity. HMW HA in the intact spinal
cord acts to maintain quiescence of neural stem cells, astrocytes and immune cells. After injury,
native, HMW HA is degraded into low MW (LMW) fragments (<200 kDa) that initiate the
wound healing response. As healing progresses, the HMW HA ECM re-establishes resolving the
inflammatory response. In SCI, the wound healing process stalls. HA hydrogels have shown
promise in laboratory studies for SCI treatment, however the MW-dependent functions of HA
have yet to be fully explored. One major limitation of any biomaterial strategy is vascularization
of the regenerated tissue, which has been shown to improve SCI outcomes. Endothelial cells
(EC), which form blood vessels, experience an HA MW-dependent bioactivity, where LMW HA
promotes EC proliferation and migration, activities inhibited by HMW HA. This study aims to
thoroughly characterize the HA MW-dependent bioactivity of human brain microvascular
endothelial cells (HBMVECs), and how this bioactivity is affected when incorporating HA into
annealed macroporous, microparticle scaffolds (AMMS) made up of annealed HA
microparticles.

BIO

Josh Karam is a PhD Candidate in the Bioengineering department at the University of California,
Los Angeles in Dr. Stephanie Seidlits’ lab where he focuses on developing injectable hyaluronic
acid-based biomaterials for spinal cord repair. At UCLA, Josh received the Eugene V. Cota-
Robles Fellowship. He received his BS in Bioengineering from the University of California,
Riverside where he was a MARC U STAR and UC LEADS Fellow performing research on the
development of dynamic suspension bioreactors for human embryonic stem cell culture.