Brief Report: Reconstruction of Joint Hyaline Cartilage by Autologous Progenitor Cells Derived from Ear Elastic Cartilage

Abstract

In healthy joints, hyaline cartilage covering the joint surfaces of bones provides cushioning due to its unique mechanical properties. However, because of its limited regenerative capacity, age-and sports-related injuries to this tissue may lead to degenerative arthropathies, prompting researchers to investigate a variety of cell sources. We recently succeeded in isolating human cartilage progenitor cells from ear elastic cartilage. Human cartilage progenitor cells have high chondrogenic and proliferative potential to form elastic cartilage with long-term tissue maintenance. However, it is unknown whether ear-derived cartilage progenitor cells can be used to reconstruct hyaline cartilage, which has different mechanical and histological properties from elastic cartilage. In our efforts to develop foundational technologies for joint hyaline cartilage repair and reconstruction, we conducted this study to obtain an answer to this question. We created an experimental canine model of knee joint cartilage damage, transplanted ear-derived autologous cartilage progenitor cells. The reconstructed cartilage was rich in proteoglycans and showed unique histological characteristics similar to joint hyaline cartilage. In addition, mechanical properties of the reconstructed tissues were higher than those of ear cartilage and equal to those of joint hyaline cartilage. This study suggested that joint hyaline cartilage was reconstructed from ear-derived cartilage progenitor cells. It also demonstrated that ear-derived cartilage progenitor cells, which can be harvested by a minimally invasive method, would be useful for reconstructing joint hyaline cartilage in patients with degenerative arthropathies. STEM CELLS 2014;32:816-821

Xiphoid Process-Derived Chondrocytes: A Novel Cell Source for Elastic Cartilage Regeneration

“…Moreover, subcutaneously transplanted eCPCs expanded in vitro were shown to regenerate elastic cartilage. However, when these cells were differentiated in vitro and transplanted onto a full-thickness cartilage defect of the joint, they regenerated hyaline cartilage tissue positive for type II and type X collagen and negative for type I collagen and elastin [31]. In contrast to these reports, our results showed that transplanting XCs onto a full-thickness defect of joint cartilage resulted in elastic cartilage tissue in approximately 34% of cases ( Fig.…”

Role of regeneration in tissue repairing and therapies

“…Hence, articular chondrocytes are restricted and controlled not to differentiate into a hypertrophic stage by using autocrine and paracrine factors and extracellular matrix microenvironment. But these retain potential to undergo hypertrophy [115]. Moreover, for increased knee cartilage volume in degenerative joint disease cutaneously implanted autologous mesenchymal stem cells are used [116].…”

“…But there is a possibility for development of strategies to treat age-onset diseases and facilitate stemcell-based therapies in older individuals [170]. Hence, there was felt a strong need of new reagents that could activate recruiting of intrinsic and extrinsic factors to induce implant progenitor cells into the damaged sites for repairing of tissues in old age people [115]. Similarly, it is also an important area of research to identify and use totipotency factors in the ooplasm and epigenic reprogramming of the transplanted genes.…”

Cartilage repair techniques in the knee: stem cell therapies

“…With the intent of evaluation with models that is more relevant to clinical condition in humans, large animals such as pig and sheep have been used as experimental subjects [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52]. Among those, a (mini)pig model has been most frequently employed in previous studies [37][38][39][40][41][42][43][44].…”

“…Muscle-derived MSC has been investigated as a cell source [74], and potentials of other sources such as placenta [75], amnion [76], umbilical cord blood [77], and ear elastic cartilage [78] have been tested in previous in vitro and animal studies.…”