Osteogenic potential of bone marrow stromal cells on smooth, roughened, and tricalcium phosphate-modified titanium alloy surfaces.
OBJECTIVE
This study investigated the influence of smooth, roughened, and tricalcium phosphate (TCP)-coated roughened titanium-aluminum-vanadium (Ti-6Al-4V) surfaces on the osteogenic potential of rat bone marrow stromal cells (BMSCs).


METHODS
Machined smooth (MS), grit-blasted roughened (MT), and roughened surfaces coated with TCP were prepared from Ti-6Al-4V. Plastic surfaces were used as a control. Surface topography and chemical characteristics were determined. Cell attachment, morphology, proliferation, and temporal expression of mRNA and protein markers associated with bone healing were examined.


RESULTS
Roughness values were 0.09 ± 0.02 Μm, 2.71 ± 0.24 Μm, and 6.08 ± 0.62 Μm for MS, MT, and TCP, respectively. Cell attachment was similar on all surfaces. The cell expansion phase occurred during days 1 to 3 on MS surfaces and days 3 to 5 on MT and TCP surfaces. The earlier onset of differentiation on MS surfaces versus MT and TCP surfaces was evidenced by: high mRNA expression peak for Runx2 at day 5 on MS (day 7 on MT and TCP); higher mRNA expression for osteopontin, osteonectin, bone sialoprotein (BSP), osteocalcin, type 1 collagen, and alkaline phosphatase over days 5 to 12 on MS compared with MT and TCP; higher levels of bone matrix proteins on MS compared with MT, with only BSP detected on TCP; cell morphology consistent with descriptions of differentiating osteoblasts apparent at day 5 on MS and absent on MT. Compared to plastic surfaces, Ti-6Al-4V appeared to suppress mRNA for interleukin 1Β, tumor necrosis factor alpha, and peroxisome proliferator-activated receptor gamma expression and upregulate osteoprotegerin.


CONCLUSIONS
Cell expansion was delayed on roughened Ti-6Al-4V surfaces, impeding osteoblast differentiation and bone matrix synthesis. These results disagree with a number of published studies examining pure titanium. Ti-6Al-4V surfaces appear to assist in the resolution of proinflammatory cytokines and inhibit BMSC differentiation toward adipocytes.
Mineralised Tissue Group, Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff, United Kingdom.
John S
JS
Colombo
Albert
A
Carley
Garry J P
GJ
Fleming
St John
SJ
Crean
Alastair J
AJ
Sloan
Rachel J
RJ
Waddington
D000469:Alkaline Phosphatase / Q000378:metabolism; D000497:Alloys / Q000737:chemistry; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002130:Calcium Phosphates; D002448:Cell Adhesion / Q000502:physiology; D002454:Cell Differentiation; D049109:Cell Proliferation; D015921:Dental Implants; D058574:Integrin-Binding Sialoprotein / Q000378:metabolism; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000502:physiology*; D016348:Osseointegration / Q000502:physiology*; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology; D015675:Osteocalcin / Q000378:metabolism; D010012:Osteogenesis / Q000502:physiology; D053495:Osteopontin / Q000378:metabolism; D047495:PPAR gamma / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D014639:Vanadium / Q000378:metabolism
D000497:Alloys; D015415:Biomarkers; D002130:Calcium Phosphates; D015921:Dental Implants; D058574:Integrin-Binding Sialoprotein; D047495:PPAR gamma; D014639:Vanadium; D015675:Osteocalcin; D053495:Osteopontin; C031462:titanium alloy (TiAl6V4); D014025:Titanium; D000469:Alkaline Phosphatase; C018392:tricalcium phosphate