Mesenchymal Stem Cell Morphology in a Fibrous Microenvironment With Length Scales Matching the Native Meniscus

The meniscus is a crescent shaped fibrocartilage in the knee comprised of a circumferentially aligned collagenous extracellular matrix (ECM) that functions to transmit load and enhance joint stability. The meniscus ECM varies as a function of region, where the inner meniscus is comprised of 70% collagen (60% type II vs. 40% type I), while the outer meniscus contains 80% collagen (99% type I) [1]. Similarly, cells within the inner meniscus are rounder and more ‘chondrocyte-like’, while those in the outer meniscus are elongated and ‘fibroblast-like’ [2]. Injury of the meniscus alters joint loading and hastens the onset of osteoarthritis. As meniscus healing is limited, there exists a need for functional meniscus replacements.