Chondrogenic differentiation of neonatal human dermal fibroblasts encapsulated in alginate beads with hydrostatic compression under hypoxic conditions in the presence of bone morphogenetic protein‐2

Abstract

In the present work, neonatal human dermal fibroblasts (nHDFs) were evaluated as a potential cell source for intervertebral disc repair. Chondrogenic differentiation of nHDFs was studied in the presence or absence of hydrostatic compression under normal and hypoxic conditions. In addition, the potentially synergistic effects of mechanical stimulation and bone morphogenetic protein (BMP)-2 on the chondrogenic differentiation of nHDFs were assessed. Mechanical stimulation was applied to the cells encapsulated in alginate beads using a custom-built bioreactor system for either a 1- or 3-week period at a frequency of 1 Hz for 4 h/day. In general, after 21 days of culture, high cell viability was observed for all the groups, with the exception of the groups exposed to intermittent mechanical stimulation for 3 weeks. Long-term intermittent application of mechanical stimulation under low O(2) conditions resulted in elevated collagen biosynthesis rate from day 0. Inclusion of BMP-2 for this group improved the chondrogenic differentiation of nHDFs, as indicated by elevated aggrecan gene expression and an increased collagen production rate compared to the day 0 group. Thus, the combination of hypoxia, BMP-2 supplementation, and long-term intermittent application of dynamic hydrostatic pressure was found to be a potent promoter of the chondrogenic differentiation of nHDFs.

Chondrogenic potential of human dermal fibroblasts in a contractile, soft, self-assembling, peptide hydrogel

“…Other groups have also provided evidence of the plasticity of dermal fibroblasts towards chondrogenesis in different 3D culture systems, such as high‐density micromass (Nicoll et al ., ; Yin et al ., ) or in combination with biomaterials: demineralized bone powder–collagen composites (Mizuno and Glowacki, ; Yates et al ., ), alginate beads (Singh et al ., ), macroporous gelatin scaffolds (Sommar et al ., ), etc. On the one hand, micromass cultures certainly provide higher cellular interactions – essential in the chondrogenic process – and the production of a homogeneous chondrogenic matrix.…”

“…They can be easily harvested from a small skin biopsy and yields obtained by routine expansion are considerably higher than for MSCs. Furthermore, prior studies have shown the potential of non‐selected human dermal fibroblasts to differentiate into osteoblast‐like (Hee et al ., ; Hee and Nicoll, ; Junker et al ., ; Sommar et al ., ; Blasi et al ., ), adipocyte‐like (Junker et al ., ; Sommar et al ., ; Blasi et al ., ) and chondrocyte‐like (Mizuno and Glowacki, ; Nicoll et al ., ; Yates et al ., ; Junker et al ., ; Sommar et al ., ; Yin et al ., ; Singh et al ., ) phenotypes under induction medium. Even differentiation into the hepatic lineage has been also reported from dermal fibroblasts (Lysy et al ., ).…”

Cellular reprogramming for clinical cartilage repair

“…Therefore, it is hypothesized that low oxygen concentrations (5% O 2 ) improve chondrogenic conversion of fibroblasts and regulates fibroblastic type I collagen production. Indeed, fibroblasts cultured in hypoxic conditions and chondrogenic medium have shown to lower type I collagen abundance compared to normal culture conditions (20% O 2 ) (Kalpakci et al 2014; Singh et al 2011). Although hypoxic differentiation advances the cells further towards a chondrogenic phenotype, the attendance of residual fibroblasts cannot be excluded and therefore represents a risk for human transplantation.…”

Harnessing Cell–Biomaterial Interactions for Osteochondral Tissue Regeneration

“…Treating adult hDFs with IGF-1 before culturing them on aggrecan led to production of type II collagen as observed by immunohistochemical staining [91]. Additionally, exposing entrapped neonatal hDFs in alginate beads to 5% oxygen with 100 ng/mL BMP-2 under 3 weeks of hydrostatic compression (1 Hz for 4 h/day) increased collagen production and aggrecan gene expression compared with static culture conditions [92]. Dermis-isolated, aggrecan-sensitive cells, which are isolated by culturing dermal fibroblasts in a monolayer on aggrecan, can be cultured as a micromass in an agarose gel [93].…”