Biomedical Engineering Reference
In-Depth Information
CHAPTER 12
ENGINEERING PEPTIDES IN HYDROGELS FOR CARTILAGE
TISSUE REGENERATION
Zhaoyang Ye and Jennifer Elisseeff
*
Department of Biomedical Engineering, Johns Hopkins University, Baltimore,
MD 21218, USA
*
E-mail: jhe@bme.jhu.edu
1. Introduction
It is estimated that severe cartilage degeneration due to osteoarthritis (OA)
afflicts 26.9 million of Americans with joint pain and life-long debilitation in
some cases [1]. Articular cartilage covers the subchondral bone and serves to
reduce joint stress and surface friction in normal diarthrodial joint. Trauma and
diseases of the synovial joint can result in structural damages to the articular
cartilage layer. Articular cartilage in adults is a comparatively avascular,
alymphatic, and aneural tissue with cellular volume averaging only
approximately 2% of the total cartilage volume. Chondrocytes are the principle
resident cells, which are responsible for the secretion of extracellular matrix
(ECM), even though mesenchymal progenitor cells (MPCs) might exist as well
[2]. Chondrocytes receive oxygen and nutrients only through diffusion through
tissue fluid or synovium in cartilage. When damaged, there is only limited
spontaneous repair [3]. Clinically, to induce cartilage tissue repair, mechanical
penetration of the subchondral bone to stimulate marrow infusion (e.g.,
microfracture), cartilage/osteochondral, periosteum and perichondrium grafts or
autologous chondrocyte implantation (ACI) have been exploited with some
success. However, these procedures are effective only for chondral defects of
limited sizes and generally, the long-term biomechanical and biochemical
properties of the resulting tissue fail to match that of native cartilage [4].
Functional
restoration
of
degenerated
articular
cartilage
still
remains
unobtainable.
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