Relevance of meniscal cell regional phenotype to tissue engineering

ABSTRACT

Purpose: Meniscus contains heterogeneous populations of cells that have not been fully characterized. Cell phenotype is often lost during culture; however, culture expansion is typically required for tissue engineering. We examined and compared cell-surface molecule expression levels on human meniscus cells from the vascular and avascular regions and articular chondrocytes while documenting changes during culture-induced dedifferentiation. Materials and Methods: Expressions of 16 different surface molecules were examined by flow cytometry after monolayer culture for 24 h, 1 week, and 2 weeks. Menisci were also immunostained to document the spatial distributions of selected surface molecules. Results: Meniscus cells and chondrocytes exhibited several similarities in surface molecule profiles with dynamic changes during culture. A greater percentage of meniscal cells were positive for CD14, CD26, CD49c, and CD49f compared to articular chondrocytes. Initially, more meniscal cells from the vascular region were positive for CD90 compared to cells from the avascular region or chondrocytes. Cells from the vascular region also expressed higher levels of CD166 and CD271 compared to cells from the avascular region. CD90, CD166, and CD271-positive cells were predominately perivascular in location. However, CD166-positive cells were also located in the superficial layer and in the adjacent synovial and adipose tissue. Conclusions: These surface marker profiles provide a target phenotype for differentiation of progenitors in tissue engineering. The spatial location of progenitor cells in meniscus is consistent with higher regenerative capacity of the vascular region, while the surface progenitor subpopulations have potential to be utilized in tears created in the avascular region.

KEYWORDS:

• Articular cartilage
• cell phenotype
• dedifferentiation
• flow cytometry
• meniscus

Acknowledgments

We are grateful for the technical support by Sujata Sovani, Yukio Akasaki, Emily Lee, and Tammy Lee (immunostainings), and by Judy Blake (copyediting).

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Funding

The National Institutes of Health (P01 AG007996), the Shaffer Family Foundation, and Donald and Darlene Shiley provided funding for this project.

Supplemental Material

Supplementary files referred to in this article can be accessed on the publisher‘s website.

Additional information

Funding

The National Institutes of Health (P01 AG007996), the Shaffer Family Foundation, and Donald and Darlene Shiley provided funding for this project.