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Similar healthy osteoclast and osteoblast activity on nanocrystalline hydroxyapatite and nanoparticles of tri-calcium phosphate compared to natural bone.

MacMillan AK, Lamberti FV, Moulton JN, Geilich BM, Webster TJ - Int J Nanomedicine (2014)

Bottom Line: Moreover, while it is now well documented that bone formation is enhanced on nanoceramics compared to micron ceramics, some have pondered whether osteoblast functions (such as osteoprotegerin and RANK ligand [RANKL]) are normal (ie, non-diseased) on such materials compared to natural bone.For these reasons, the objective of the present in vitro study was to determine various functions of osteoclasts and osteoblasts on nanocrystalline and micron crystalline hydroxyapatite as well as tri-calcium phosphate materials and compare such results to cortical and cancellous bone.It also provides the first data of healthy osteoclast and osteoblast functions on nanocrystalline calcium phosphates compared to natural bone.

View Article: PubMed Central - PubMed

Affiliation: RTI Surgical, Alachua, FL, USA.

ABSTRACT
While there have been numerous studies to determine osteoblast (bone forming cell) functions on nanocrystalline compared to micron crystalline ceramics, there have been few studies which have examined osteoclast activity (including tartrate-resistant acid phosphatase, formation of resorption pits, size of resorption pits, and receptor activator of nuclear factor κB [RANK]). This is despite the fact that osteoclasts are an important part of maintaining healthy bone since they resorb bone during the bone remodeling process. Moreover, while it is now well documented that bone formation is enhanced on nanoceramics compared to micron ceramics, some have pondered whether osteoblast functions (such as osteoprotegerin and RANK ligand [RANKL]) are normal (ie, non-diseased) on such materials compared to natural bone. For these reasons, the objective of the present in vitro study was to determine various functions of osteoclasts and osteoblasts on nanocrystalline and micron crystalline hydroxyapatite as well as tri-calcium phosphate materials and compare such results to cortical and cancellous bone. Results showed for the first time similar osteoclast activity (including tartrate-resistant acid phosphatase, formation of resorption pits, size of resorption pits, and RANK) and osteoblast activity (osteoprotegerin and RANKL) on nanocrystalline hydroxyapatite compared to natural bone, whereas osteoclast and osteoblast functions on micron crystalline versions of these ceramics were much different than natural bone. In this manner, this study provides additional evidence that nanocrystalline calcium phosphates can serve as suitable synthetic analogs to natural bone to improve numerous orthopedic applications. It also provides the first data of healthy osteoclast and osteoblast functions on nanocrystalline calcium phosphates compared to natural bone.

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Size of resorption pits on the selected calcium phosphate materials.Notes: The size of resorption pits decreased with increased crystal grain size. Data = mean ± standard error of the mean; N=3; *P<0.01 compared to cancellous bone at the same time period; **P<0.01 compared to all micron materials (HA, TCP, and TCP/HA) at the same time period. All values are significantly different from one time period to the next for the same sample (except for Si-substituted micron-HA and micro HA/TCP).Abbreviations: HA, hydroxyapatite; Si-sub, Si-substituted; TCP, tri-calcium phosphates.
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f8-ijn-9-5627: Size of resorption pits on the selected calcium phosphate materials.Notes: The size of resorption pits decreased with increased crystal grain size. Data = mean ± standard error of the mean; N=3; *P<0.01 compared to cancellous bone at the same time period; **P<0.01 compared to all micron materials (HA, TCP, and TCP/HA) at the same time period. All values are significantly different from one time period to the next for the same sample (except for Si-substituted micron-HA and micro HA/TCP).Abbreviations: HA, hydroxyapatite; Si-sub, Si-substituted; TCP, tri-calcium phosphates.

Mentions: More importantly, results of the present in vitro study demonstrated for the first time similar TRAP activity (Figure 6) and number of resorption pits (Figure 7) formed by osteoclasts on porous nano-HA, porous nano biphasic TCP/HA, porous nano-TCP compared to cancellous and cortical bone after each time period. In contrast, TRAP activity and number of resorption pits on the micron equivalents were not similar to either cancellous or cortical bone, with the exception of the number of resorption pits on micron-TCP at 21 days culture. The size of the resorption pits formed by osteoclasts was similar on porous nano-HA compared to cortical bone, and porous nano-TCP, nano biphasic TCP/HA, and sintered nano-HA compared to cancellous bone after each time period (Figures 8 and 9). In contrast, the size of the resorption pits formed by osteoclasts was not similar on all other micron materials compared to bone. Importantly, these results suggest that regardless of surface area (porous versus dense), increased responses of osteoclasts were measured on nanocrystalline compared to micron crystalline calcium phosphate based materials. Moreover, similar results to cellular behavior on bone were obtained regardless of crystalline phase as long as nano compared to micron materials were compared.


Similar healthy osteoclast and osteoblast activity on nanocrystalline hydroxyapatite and nanoparticles of tri-calcium phosphate compared to natural bone.

MacMillan AK, Lamberti FV, Moulton JN, Geilich BM, Webster TJ - Int J Nanomedicine (2014)

Size of resorption pits on the selected calcium phosphate materials.Notes: The size of resorption pits decreased with increased crystal grain size. Data = mean ± standard error of the mean; N=3; *P<0.01 compared to cancellous bone at the same time period; **P<0.01 compared to all micron materials (HA, TCP, and TCP/HA) at the same time period. All values are significantly different from one time period to the next for the same sample (except for Si-substituted micron-HA and micro HA/TCP).Abbreviations: HA, hydroxyapatite; Si-sub, Si-substituted; TCP, tri-calcium phosphates.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4260657&req=5

f8-ijn-9-5627: Size of resorption pits on the selected calcium phosphate materials.Notes: The size of resorption pits decreased with increased crystal grain size. Data = mean ± standard error of the mean; N=3; *P<0.01 compared to cancellous bone at the same time period; **P<0.01 compared to all micron materials (HA, TCP, and TCP/HA) at the same time period. All values are significantly different from one time period to the next for the same sample (except for Si-substituted micron-HA and micro HA/TCP).Abbreviations: HA, hydroxyapatite; Si-sub, Si-substituted; TCP, tri-calcium phosphates.
Mentions: More importantly, results of the present in vitro study demonstrated for the first time similar TRAP activity (Figure 6) and number of resorption pits (Figure 7) formed by osteoclasts on porous nano-HA, porous nano biphasic TCP/HA, porous nano-TCP compared to cancellous and cortical bone after each time period. In contrast, TRAP activity and number of resorption pits on the micron equivalents were not similar to either cancellous or cortical bone, with the exception of the number of resorption pits on micron-TCP at 21 days culture. The size of the resorption pits formed by osteoclasts was similar on porous nano-HA compared to cortical bone, and porous nano-TCP, nano biphasic TCP/HA, and sintered nano-HA compared to cancellous bone after each time period (Figures 8 and 9). In contrast, the size of the resorption pits formed by osteoclasts was not similar on all other micron materials compared to bone. Importantly, these results suggest that regardless of surface area (porous versus dense), increased responses of osteoclasts were measured on nanocrystalline compared to micron crystalline calcium phosphate based materials. Moreover, similar results to cellular behavior on bone were obtained regardless of crystalline phase as long as nano compared to micron materials were compared.

Bottom Line: Moreover, while it is now well documented that bone formation is enhanced on nanoceramics compared to micron ceramics, some have pondered whether osteoblast functions (such as osteoprotegerin and RANK ligand [RANKL]) are normal (ie, non-diseased) on such materials compared to natural bone.For these reasons, the objective of the present in vitro study was to determine various functions of osteoclasts and osteoblasts on nanocrystalline and micron crystalline hydroxyapatite as well as tri-calcium phosphate materials and compare such results to cortical and cancellous bone.It also provides the first data of healthy osteoclast and osteoblast functions on nanocrystalline calcium phosphates compared to natural bone.

View Article: PubMed Central - PubMed

Affiliation: RTI Surgical, Alachua, FL, USA.

ABSTRACT
While there have been numerous studies to determine osteoblast (bone forming cell) functions on nanocrystalline compared to micron crystalline ceramics, there have been few studies which have examined osteoclast activity (including tartrate-resistant acid phosphatase, formation of resorption pits, size of resorption pits, and receptor activator of nuclear factor κB [RANK]). This is despite the fact that osteoclasts are an important part of maintaining healthy bone since they resorb bone during the bone remodeling process. Moreover, while it is now well documented that bone formation is enhanced on nanoceramics compared to micron ceramics, some have pondered whether osteoblast functions (such as osteoprotegerin and RANK ligand [RANKL]) are normal (ie, non-diseased) on such materials compared to natural bone. For these reasons, the objective of the present in vitro study was to determine various functions of osteoclasts and osteoblasts on nanocrystalline and micron crystalline hydroxyapatite as well as tri-calcium phosphate materials and compare such results to cortical and cancellous bone. Results showed for the first time similar osteoclast activity (including tartrate-resistant acid phosphatase, formation of resorption pits, size of resorption pits, and RANK) and osteoblast activity (osteoprotegerin and RANKL) on nanocrystalline hydroxyapatite compared to natural bone, whereas osteoclast and osteoblast functions on micron crystalline versions of these ceramics were much different than natural bone. In this manner, this study provides additional evidence that nanocrystalline calcium phosphates can serve as suitable synthetic analogs to natural bone to improve numerous orthopedic applications. It also provides the first data of healthy osteoclast and osteoblast functions on nanocrystalline calcium phosphates compared to natural bone.

Show MeSH
Related in: MedlinePlus