Osteoblast maturation and new bone formation in response to titanium implant surface features are reduced with age

Abstract

The surface properties of materials contribute to host cellular response and play a significant role in determining the overall success or failure of an implanted biomaterial. Rough titanium (Ti) surface microtopography and high surface free energy have been shown to enhance osteoblast maturation in vitro and increase bone formation in vivo. While the surface properties of Ti are known to affect osteoblast response, host bone quality also plays a significant role in determining successful osseointegration. One factor affecting host bone quality is patient age. We examined both in vitro and in vivo whether response to Ti surface features was affected by animal age. Calvarial osteoblasts isolated from 1-, 3-, and 11-month-old rats all displayed a reduction in cell number and increases in alkaline phosphatase specific activity and osteocalcin in response to increasing Ti surface microtopography and surface energy. Further, osteoblasts from the three ages examined displayed increased production of osteocalcin and local factors osteoprotegerin, VEGF-A, and active TGF-β1 in response to increasing Ti surface roughness and surface energy. Latent TGF-β1 only increased in cultures of osteoblasts from 1- and 3-month-old rats. Treatment with the systemic osteotropic hormone 1α,25(OH)2D3 further enhanced the response of osteoblasts to Ti surface features for all three age groups. However, osteoblasts derived from 11-month-old animals had a reduced response to 1α,25(OH)2D3 as compared to osteoblasts derived from 1-or 3-month-old animals. These results were confirmed in vivo. Ti implants placed in the femoral intramedullary canal of old (9-month) mice yielded lower bone-to-implant contract and neovascularization in response to Ti surface roughness and energy compared to younger (2-month) mice. These results show that rodent osteoblast maturation in vitro as well as new bone formation in vivo is reduced with age. Whether comparable age differences exist in humans needs to be determined.

Derivation of Stromal (Skeletal and Mesenchymal) Stem-Like Cells from Human Embryonic Stem Cells

“…We have employed the hEB model for hESC differentiation to obtain hMSC population. Several different techniques have been reported that induce differentiation of hESC toward osteogenic lineages including EB formation [27][28][29], monolayer differentiation [30][31][32][33], through coculture with OP9 cells [3,6,31,32,34] or fibroblasts [35]. Although monolayer and coculture methods may increase homogeneity of cells during differentiation, they fail to recapitulate the morphological changes occurring in a more ''natural'' context that is provided during EB differentiation [33,36].…”

A review on the wettability of dental implant surfaces II: Biological and clinical aspects

“…The influence of implant surface wettability transcends its role at the protein and cellular level, and has been confirmed in vivo and in the clinic [11, 28, 42, 61, 85, 121–123]. Hydrophilic surfaces of experimental, relatively smooth (R a < 0.8 μm) disk-shaped Ti implants were shown to promote early bone formation compared to hydrophobic surfaces [28].…”

“…Finally, Olivares-Navarrete et al studied if the effects of surface characteristics such as surface roughness and wettability could be affected by age in a novel murine femoral intramedullary bone formation model using machined, BAE and modBAE implants [123]. The results revealed that after 4 weeks the old mice (9-month old) developed significantly higher bone-to-implant contact on modBAE surfaces compared to machined surfaces, in contrast to younger mice (2-month old), which presented similarly high levels on all three surfaces.…”

The Effects of Hyperlipidemia on Implant Osseointegration in the Mouse Femur

“…The effects of hyperlipidemia on bone health may also interfere with dental implant therapy since the host’s bone quantity, quality and healing potential play an important role in osseointegration(Fedele, Sabbah et al 2011; Gaetti-Jardim, Santiago-Junior et al 2011; Olivares-Navarrete, Raines et al 2012). Currently, the role of hyperlipidemia in implant osseointegration is unknown.…”