International Journal of Molecular Sciences

Research

13 pages, 3359 KiB

Open AccessArticle

Lipoteichoic Acid Accelerates Bone Healing by Enhancing Osteoblast Differentiation and Inhibiting Osteoclast Activation in a Mouse Model of Femoral Defects

by Chih-Chien Hu, Chih-Hsiang Chang, Yi-min Hsiao, Yuhan Chang, Ying-Yu Wu, Steve W. N. Ueng and Mei-Feng Chen

Int. J. Mol. Sci. 2020, 21(15), 5550; https://doi.org/10.3390/ijms21155550 - 3 Aug 2020

Cited by 12 | Viewed by 3274

Abstract

Lipoteichoic acid (LTA) is a cell wall component of Gram-positive bacteria. Limited data suggest that LTA is beneficial for bone regeneration in vitro. Thus, we used a mouse model of femoral defects to explore the effects of LTA on bone healing in vivo. [...] Read more.

Lipoteichoic acid (LTA) is a cell wall component of Gram-positive bacteria. Limited data suggest that LTA is beneficial for bone regeneration in vitro. Thus, we used a mouse model of femoral defects to explore the effects of LTA on bone healing in vivo. Micro-computed tomography analysis and double-fluorochrome labeling were utilized to examine whether LTA can accelerate dynamic bone formation in vivo. The effects of LTA on osteoblastogenesis and osteoclastogenesis were also studied in vitro. LTA treatment induced prompt bone bridge formation, rapid endochondral ossification, and accelerated healing of fractures in mice with femoral bone defects. In vitro, LTA directly enhanced indicators of osteogenic factor-induced MC3T3-E1 cell differentiation, including alkaline phosphatase activity, calcium deposition and osteopontin expression. LTA also inhibited osteoclast activation induced by receptor activator of nuclear factor-kappa B ligand. We identified six molecules that may be associated with LTA-accelerated bone healing: monocyte chemoattractant protein 1, chemokine (C-X-C motif) ligand 1, cystatin C, growth/differentiation factor 15, endostatin and neutrophil gelatinase-associated lipocalin. Finally, double-fluorochrome, dynamic-labeling data indicated that LTA significantly enhanced bone-formation rates in vivo. In conclusion, our findings suggest that LTA has promising bone-regeneration properties. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

17 pages, 5057 KiB

Open AccessArticle

Cellular Fragments as Biomaterial for Rapid In Vitro Bone-Like Tissue Synthesis

by Mst Nahid Akhter, Emilio Satoshi Hara, Koichi Kadoya, Masahiro Okada and Takuya Matsumoto

Int. J. Mol. Sci. 2020, 21(15), 5327; https://doi.org/10.3390/ijms21155327 - 27 Jul 2020

Cited by 7 | Viewed by 3503

Abstract

Current stem cell-based techniques for bone-like tissue synthesis require at least two to three weeks. Therefore, novel techniques to promote rapid 3D bone-like tissue synthesis in vitro are still required. In this study, we explored the concept of using cell nanofragments as a [...] Read more.

Current stem cell-based techniques for bone-like tissue synthesis require at least two to three weeks. Therefore, novel techniques to promote rapid 3D bone-like tissue synthesis in vitro are still required. In this study, we explored the concept of using cell nanofragments as a substrate material to promote rapid bone formation in vitro. The methods for cell nanofragment fabrication were ultrasonication (30 s and 3 min), non-ionic detergent (triton 0.1% and 1%), or freeze-dried powder. The results showed that ultrasonication for 3 min allowed the fabrication of homogeneous nanofragments of less than 150 nm in length, which mineralized surprisingly in just one day, faster than the fragments obtained from all other methods. Further optimization of culture conditions indicated that a concentration of 10 mM or 100 mM of β-glycerophosphate enhanced, whereas fetal bovine serum (FBS) inhibited in a concentration-dependent manner, the mineralization of the cell nanofragments. Finally, a 3D collagen-cell nanofragment-mineral complex mimicking a bone-like structure was generated in just two days by combining the cell nanofragments in collagen gel. In conclusion, sonication for three min could be applied as a novel method to fabricate cell nanofragments of less than 150 nm in length, which can be used as a material for in vitro bone tissue engineering. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

16 pages, 2759 KiB

Open AccessArticle

Induced Periosteum-Mimicking Membrane with Cell Barrier and Multipotential Stromal Cell (MSC) Homing Functionalities

by Heather E. Owston, Katrina M. Moisley, Giuseppe Tronci, Stephen J. Russell, Peter V. Giannoudis and Elena Jones

Int. J. Mol. Sci. 2020, 21(15), 5233; https://doi.org/10.3390/ijms21155233 - 23 Jul 2020

Cited by 9 | Viewed by 3937

Abstract

The current management of critical size bone defects (CSBDs) remains challenging and requires multiple surgeries. To reduce the number of surgeries, wrapping a biodegradable fibrous membrane around the defect to contain the graft and carry biological stimulants for repair is highly desirable. Poly(ε-caprolactone) [...] Read more.

The current management of critical size bone defects (CSBDs) remains challenging and requires multiple surgeries. To reduce the number of surgeries, wrapping a biodegradable fibrous membrane around the defect to contain the graft and carry biological stimulants for repair is highly desirable. Poly(ε-caprolactone) (PCL) can be utilised to realise nonwoven fibrous barrier-like structures through free surface electrospinning (FSE). Human periosteum and induced membrane (IM) samples informed the development of an FSE membrane to support platelet lysate (PL) absorption, multipotential stromal cells (MSC) growth, and the prevention of cell migration. Although thinner than IM, periosteum presented a more mature vascular system with a significantly larger blood vessel diameter. The electrospun membrane (PCL3%-E) exhibited randomly configured nanoscale fibres that were successfully customised to introduce pores of increased diameter, without compromising tensile properties. Additional to the PL absorption and release capabilities needed for MSC attraction and growth, PCL3%-E also provided a favourable surface for the proliferation and alignment of periosteum- and bone marrow derived-MSCs, whilst possessing a barrier function to cell migration. These results demonstrate the development of a promising biodegradable barrier membrane enabling PL release and MSC colonisation, two key functionalities needed for the in situ formation of a transitional periosteum-like structure, enabling movement towards single-surgery CSBD reconstruction. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

13 pages, 5676 KiB

Open AccessCommunication

Augmentation of Bone Regeneration by Depletion of Stress-Induced Senescent Cells Using Catechin and Senolytics

by Yoshitomo Honda, Anqi Huang, Tomonari Tanaka, Xiaoyu Han, Beiyuan Gao, Haitao Liu, Xinchen Wang, Jianxin Zhao, Yoshiya Hashimoto, Kazuyo Yamamoto, Naoyuki Matsumoto, Shunsuke Baba and Makoto Umeda

Int. J. Mol. Sci. 2020, 21(12), 4213; https://doi.org/10.3390/ijms21124213 - 13 Jun 2020

Cited by 18 | Viewed by 3942

Abstract

Despite advances in bone regenerative medicine, the relationship between stress-induced premature senescence (SIPS) in cells and bone regeneration remains largely unknown. Herein, we demonstrated that the implantation of a lipopolysaccharide (LPS) sustained-release gelatin sponge (LS-G) increases the number of SIPS cells and that [...] Read more.

Despite advances in bone regenerative medicine, the relationship between stress-induced premature senescence (SIPS) in cells and bone regeneration remains largely unknown. Herein, we demonstrated that the implantation of a lipopolysaccharide (LPS) sustained-release gelatin sponge (LS-G) increases the number of SIPS cells and that the elimination of these cells promotes bone formation in critical-sized bone defects in the rat calvaria. Histological (hematoxylin–eosin and SA-β-gal) and immunohistological (p16 and p21 for analyzing cellular senescence and 4-HNE for oxidation) staining was used to identify SIPS cells and elucidate the underlying mechanism. Bone formation in defects were analyzed using microcomputed tomography, one and four weeks after surgery. Parallel to LS-G implantation, local epigallocatechin gallate (EGCG) administration, and systemic senolytic (dasatinib and quercetin: D+Q) administration were used to eliminate SIPS cells. After LS-G implantation, SA-β-gal-, p16-, and p21-positive cells (SIPS cells) accumulated in the defects. However, treatment with LS-G+EGCG and LS-G+D+Q resulted in lower numbers of SIPS cells than that with LS-G in the defects, resulting in an augmentation of newly formed bone. We demonstrated that SIPS cells induced by sustained stimulation by LPS may play a deleterious role in bone formation. Controlling these cell numbers is a promising strategy to increase bone regeneration. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

17 pages, 3626 KiB

Open AccessArticle

UV-Pre-Treated and Protein-Adsorbed Titanium Implants Exhibit Enhanced Osteoconductivity

by Yoshihiko Sugita, Juri Saruta, Takashi Taniyama, Hiroaki Kitajima, Makoto Hirota, Takayuki Ikeda and Takahiro Ogawa

Int. J. Mol. Sci. 2020, 21(12), 4194; https://doi.org/10.3390/ijms21124194 - 12 Jun 2020

Cited by 27 | Viewed by 2840

Abstract

Titanium materials are essential treatment modalities in the medical field and serve as a tissue engineering scaffold and coating material for medical devices. Thus, there is a significant demand to improve the bioactivity of titanium for therapeutic and experimental purposes. We showed that [...] Read more.

Titanium materials are essential treatment modalities in the medical field and serve as a tissue engineering scaffold and coating material for medical devices. Thus, there is a significant demand to improve the bioactivity of titanium for therapeutic and experimental purposes. We showed that ultraviolet light (UV)-pre-treatment changed the protein-adsorption ability and subsequent osteoconductivity of titanium. Fibronectin (FN) adsorption on UV-treated titanium was 20% and 30% greater after 1-min and 1-h incubation, respectively, than that of control titanium. After 3-h incubation, FN adsorption on UV-treated titanium remained 30% higher than that on the control. Osteoblasts were cultured on titanium disks after 1-h FN adsorption with or without UV-pre-treatment and on titanium disks without FN adsorption. The number of attached osteoblasts during the early stage of culture was 80% greater on UV-treated and FN-adsorbed (UV/FN) titanium than on FN-adsorbed (FN) titanium; osteoblasts attachment on UV/FN titanium was 2.6- and 2.1-fold greater than that on control- and UV-treated titanium, respectively. The alkaline phosphatase activity of osteoblasts on UV/FN titanium was increased 1.8-, 1.8-, and 2.4-fold compared with that on FN-adsorbed, UV-treated, and control titanium, respectively. The UV/FN implants exhibited 25% and 150% greater in vivo biomechanical strength of bone integration than the FN- and control implants, respectively. Bone morphogenetic protein-2 (BMP-2) adsorption on UV-treated titanium was 4.5-fold greater than that on control titanium after 1-min incubation, resulting in a 4-fold increase in osteoblast attachment. Thus, UV-pre-treatment of titanium accelerated its protein adsorptivity and osteoconductivity, providing a novel strategy for enhancing its bioactivity. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

18 pages, 2203 KiB

Open AccessArticle

The Effect of TBB, as an Initiator, on the Biological Compatibility of PMMA/MMA Bone Cement

by Kosuke Hamajima, Ryotaro Ozawa, Juri Saruta, Makiko Saita, Hiroaki Kitajima, Samira Rahim Taleghani, Dan Usami, Donya Goharian, Mitsunori Uno, Ken Miyazawa, Shigemi Goto, Keiichi Tsukinoki and Takahiro Ogawa

Int. J. Mol. Sci. 2020, 21(11), 4016; https://doi.org/10.3390/ijms21114016 - 4 Jun 2020

Cited by 20 | Viewed by 3614

Abstract

Acrylic bone cement is widely used in orthopedic surgery for treating various conditions of the bone and joints. Bone cement consists of methyl methacrylate (MMA), polymethyl methacrylate (PMMA), and benzoyl peroxide (BPO), functioning as a liquid monomer, solid phase, and polymerization initiator, respectively. [...] Read more.

Acrylic bone cement is widely used in orthopedic surgery for treating various conditions of the bone and joints. Bone cement consists of methyl methacrylate (MMA), polymethyl methacrylate (PMMA), and benzoyl peroxide (BPO), functioning as a liquid monomer, solid phase, and polymerization initiator, respectively. However, cell and tissue toxicity caused by bone cement has been a concern. This study aimed to determine the effect of tri-n-butyl borane (TBB) as an initiator on the biocompatibility of bone cement. Rat spine bone marrow-derived osteoblasts were cultured on two commercially available PMMA-BPO bone cements and a PMMA-TBB experimental material. After a 24-h incubation, more cells survived on PMMA-TBB than on PMMA-BPO. Cytomorphometry showed that the area of cell spread was greater on PMMA-TBB than on PMMA-BPO. Analysis of alkaline phosphatase activity, gene expression, and matrix mineralization showed that the osteoblastic differentiation was substantially advanced on the PMMA-TBB. Electron spin resonance (ESR) spectroscopy revealed that polymerization radical production within the PMMA-TBB was 1/15–1/20 of that within the PMMA-BPO. Thus, the use of TBB as an initiator, improved the biocompatibility and physicochemical properties of the PMMA-based material. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

14 pages, 5512 KiB

Open AccessArticle

Bactericidal and Bioresorbable Calcium Phosphate Cements Fabricated by Silver-Containing Tricalcium Phosphate Microspheres

by Michiyo Honda, Yusuke Kawanobe, Kohei Nagata, Ken Ishii, Morio Matsumoto and Mamoru Aizawa

Int. J. Mol. Sci. 2020, 21(11), 3745; https://doi.org/10.3390/ijms21113745 - 26 May 2020

Cited by 15 | Viewed by 3082

Abstract

Bacterial adhesion to the calcium phosphate surface is a serious problem in surgery. To prevent bacterial infection, the development of calcium-phosphate cements (CPCs) with bactericidal properties is indispensable. The aim of this study was to fabricate antibacterial CPCs and evaluate their biological properties. [...] Read more.

Bacterial adhesion to the calcium phosphate surface is a serious problem in surgery. To prevent bacterial infection, the development of calcium-phosphate cements (CPCs) with bactericidal properties is indispensable. The aim of this study was to fabricate antibacterial CPCs and evaluate their biological properties. Silver-containing tricalcium phosphate (Ag-TCP) microspheres consisting of α/β-TCP phases were synthesized by an ultrasonic spray-pyrolysis technique. The powders prepared were mixed with the setting liquid to fabricate the CPCs. The resulting cements consisting of β-TCP and hydroxyapatite had a porous structure and wash-out resistance. Additionally, silver and calcium ions could be released into the culture medium from Ag-TCP cements for a long time accompanied by the dissolution of TCP. These data showed the bioresorbability of the Ag-TCP cement. In vitro antibacterial evaluation demonstrated that both released and immobilized silver suppressed the growth of bacteria and prevented bacterial adhesion to the surface of CPCs. Furthermore, histological evaluation by implantation of Ag-TCP cements into rabbit tibiae exhibited abundant bone apposition on the cement without inflammatory responses. These results showed that Ag-TCP cement has a good antibacterial property and good biocompatibility. The present Ag-TCP cements are promising for bone tissue engineering and may be used as antibacterial biomaterials. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

19 pages, 3771 KiB

Open AccessArticle

Effects of Strontium-Doped β-Tricalcium Scaffold on Longitudinal Nuclear Factor-Kappa Beta and Vascular Endothelial Growth Factor Receptor-2 Promoter Activities during Healing in a Murine Critical-Size Bone Defect Model

by Mersedeh Tohidnezhad, Yusuke Kubo, Philipp Lichte, Tobias Heigl, Diana Roch, Nazanin Barahmand Pour, Christian Bergmann, Tolga Taha Sönmez, Jennifer Vanessa Phi Hock, Athanassios Fragoulis, Felix Gremse, Stefanie Rosenhain, Alexander Slowik, Michaela Bienert, Nisreen Kweider, Christoph Jan Wruck, Holger Jahr, Frank Hildebrand, Hans Christoph Pape, Sabine Neuß, Horst Fischer and Thomas Pufe Show full author list Hide full author list

Int. J. Mol. Sci. 2020, 21(9), 3208; https://doi.org/10.3390/ijms21093208 - 1 May 2020

Cited by 11 | Viewed by 4481

Abstract

It was hypothesized that strontium (Sr)-doped β-tricalcium phosphate (TCP)-based scaffolds have a positive effect on the regeneration of large bone defects (LBD). Readouts in our mice models were nuclear factor-kappa beta (NF-κB) activity and vascular endothelial growth factor receptor-2 (VEGFR-2) promoter activity during [...] Read more.

It was hypothesized that strontium (Sr)-doped β-tricalcium phosphate (TCP)-based scaffolds have a positive effect on the regeneration of large bone defects (LBD). Readouts in our mice models were nuclear factor-kappa beta (NF-κB) activity and vascular endothelial growth factor receptor-2 (VEGFR-2) promoter activity during the healing process. A 2-mm critical-size femoral fracture was performed in transgenic NF-κB- and VEGFR-2-luciferase reporter mice. The fracture was filled with a 3D-printed β-TCP scaffold with or without Sr. A bioluminescence in-vivo imaging system was used to sequentially investigate NF-κB and VEGFR-2 expression for two months. After sacrifice, soft and osseous tissue formation in the fracture sites was histologically examined. NF-κB activity increased in the β-TCP + Sr group in the latter stage (day 40–60). VEGFR-2 activity increased in the + Sr group from days 0–15 but decreased and showed significantly less activity than the β-TCP and non-scaffold groups from days 40–60. The new bone formation and soft tissue formation in the + Sr group were significantly higher than in the β-TCP group, whereas the percentage of osseous tissue formation in the β-TCP group was significantly higher than in the β-TCP + Sr group. We analyzed longitudinal VEGFR-2 promoter activity and NF-κB activity profiles, as respective agents of angiogenesis and inflammation, during LBD healing. The extended inflammation phase and eventually more rapid resorption of scaffold caused by the addition of strontium accelerates temporary bridging of the fracture gaps. This finding has the potential to inform an improved treatment strategy for patients who suffer from osteoporosis. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

16 pages, 3485 KiB

Open AccessArticle

Directing Stem Cell Commitment by Amorphous Calcium Phosphate Nanoparticles Incorporated in PLGA: Relevance of the Free Calcium Ion Concentration

by Olivier Gröninger, Samuel Hess, Dirk Mohn, Elia Schneider, Wendelin Stark, Sonja Märsmann, Petra Wolint, Maurizio Calcagni, Paolo Cinelli and Johanna Buschmann

Int. J. Mol. Sci. 2020, 21(7), 2627; https://doi.org/10.3390/ijms21072627 - 9 Apr 2020

Cited by 17 | Viewed by 3687

Abstract

The microenvironment of mesenchymal stem cells (MSCs) is responsible for the modulation in MSC commitment. Nanocomposites with an inorganic and an organic component have been investigated, and osteogenesis of MSCs has been attributed to inorganic phases such as calcium phosphate under several conditions. [...] Read more.

The microenvironment of mesenchymal stem cells (MSCs) is responsible for the modulation in MSC commitment. Nanocomposites with an inorganic and an organic component have been investigated, and osteogenesis of MSCs has been attributed to inorganic phases such as calcium phosphate under several conditions. Here, electrospun meshes and two-dimensional films of poly(lactic-co-glycolic acid) (PLGA) or nanocomposites of PLGA and amorphous calcium phosphate nanoparticles (PLGA/aCaP) seeded with human adipose-derived stem cells (ASCs) were analyzed for the expression of selected marker genes. In a two-week in vitro experiment, osteogenic commitment was not found to be favored on PLGA/aCaP compared to pure PLGA. Analysis of the medium revealed a significant reduction of the Ca²⁺ concentration when incubated with PLGA/aCaP, caused by chemical precipitation of hydroxyapatite (HAp) on aCaP seeds of PLGA/aCaP. Upon offering a constant Ca²⁺ concentration, however, the previously observed anti-osteogenic effect was reversed: alkaline phosphatase, an early osteogenic marker gene, was upregulated on PLGA/aCaP compared to pristine PLGA. Hence, in addition to the cell–material interaction, the material–medium interaction was also important for the stem cell commitment here, affecting the cell–medium interaction. Complex in vitro models should therefore consider all factors, as coupled impacts might emerge. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

24 pages, 6110 KiB

Open AccessArticle

Novel Osteogenic Behaviors around Hydrophilic and Radical-Free 4-META/MMA-TBB: Implications of an Osseointegrating Bone Cement

by Yoshihiko Sugita, Takahisa Okubo, Makiko Saita, Manabu Ishijima, Yasuyoshi Torii, Miyuki Tanaka, Chika Iwasaki, Takeo Sekiya, Masako Tabuchi, Naser Mohammadzadeh Rezaei, Takashi Taniyama, Nobuaki Sato, Juri Saruta, Masakazu Hasegawa, Makoto Hirota, Wonhee Park, Masaichi Chang-Il Lee, Hatsuhiko Maeda and Takahiro Ogawa

Int. J. Mol. Sci. 2020, 21(7), 2405; https://doi.org/10.3390/ijms21072405 - 31 Mar 2020

Cited by 18 | Viewed by 3559

Abstract

Poly(methyl methacrylate) (PMMA)-based bone cement, which is widely used to affix orthopedic metallic implants, is considered bio-tolerant but lacks osteoconductivity and is cytotoxic. Implant loosening and toxic complications are significant and recognized problems. Here we devised two strategies to improve PMMA-based bone cement: [...] Read more.

Poly(methyl methacrylate) (PMMA)-based bone cement, which is widely used to affix orthopedic metallic implants, is considered bio-tolerant but lacks osteoconductivity and is cytotoxic. Implant loosening and toxic complications are significant and recognized problems. Here we devised two strategies to improve PMMA-based bone cement: (1) adding 4-methacryloyloxylethyl trimellitate anhydride (4-META) to MMA monomer to render it hydrophilic; and (2) using tri-n-butyl borane (TBB) as a polymerization initiator instead of benzoyl peroxide (BPO) to reduce free radical production. Rat bone marrow-derived osteoblasts were cultured on PMMA-BPO, common bone cement ingredients, and 4-META/MMA-TBB, newly formulated ingredients. After 24 h of incubation, more cells survived on 4-META/MMA-TBB than on PMMA-BPO. The mineralized area was 20-times greater on 4-META/MMA-TBB than PMMA-BPO at the later culture stage and was accompanied by upregulated osteogenic gene expression. The strength of bone-to-cement integration in rat femurs was 4- and 7-times greater for 4-META/MMA-TBB than PMMA-BPO during early- and late-stage healing, respectively. MicroCT and histomorphometric analyses revealed contact osteogenesis exclusively around 4-META/MMA-TBB, with minimal soft tissue interposition. Hydrophilicity of 4-META/MMA-TBB was sustained for 24 h, particularly under wet conditions, whereas PMMA-BPO was hydrophobic immediately after mixing and was unaffected by time or condition. Electron spin resonance (ESR) spectroscopy revealed that the free radical production for 4-META/MMA-TBB was 1/10 to 1/20 that of PMMA-BPO within 24 h, and the substantial difference persisted for at least 10 days. The compromised ability of PMMA-BPO in recruiting cells was substantially alleviated by adding free radical-scavenging amino-acid N-acetyl cysteine (NAC) into the material, whereas adding NAC did not affect the ability of 4-META/MMA-TBB. These results suggest that 4-META/MMA-TBB shows significantly reduced cytotoxicity compared to PMMA-BPO and induces osteoconductivity due to uniquely created hydrophilic and radical-free interface. Further pre-clinical and clinical validations are warranted. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

15 pages, 2133 KiB

Open AccessArticle

UV-Photofunctionalization of Titanium Promotes Mechanical Anchorage in A Rat Osteoporosis Model

by Takashi Taniyama, Juri Saruta, Naser Mohammadzadeh Rezaei, Kourosh Nakhaei, Amirreza Ghassemi, Makoto Hirota, Takahisa Okubo, Takayuki Ikeda, Yoshihiko Sugita, Masakazu Hasegawa and Takahiro Ogawa

Int. J. Mol. Sci. 2020, 21(4), 1235; https://doi.org/10.3390/ijms21041235 - 12 Feb 2020

Cited by 29 | Viewed by 3600

Abstract

Effects of UV-photofunctionalization on bone-to-titanium integration under challenging systemic conditions remain unclear. We examined the behavior and response of osteoblasts from sham-operated and ovariectomized (OVX) rats on titanium surfaces with or without UV light pre-treatment and the strength of bone-implant integration. Osteoblasts from [...] Read more.

Effects of UV-photofunctionalization on bone-to-titanium integration under challenging systemic conditions remain unclear. We examined the behavior and response of osteoblasts from sham-operated and ovariectomized (OVX) rats on titanium surfaces with or without UV light pre-treatment and the strength of bone-implant integration. Osteoblasts from OVX rats showed significantly lower alkaline phosphatase, osteogenic gene expression, and mineralization activities than those from sham rats. Bone density variables in the spine were consistently lower in OVX rats. UV-treated titanium was superhydrophilic and the contact angle of ddH₂O was ≤5°. Titanium without UV treatment was hydrophobic with a contact angle of ≥80°. Initial attachment to titanium, proliferation, alkaline phosphatase activity, and gene expression were significantly increased on UV-treated titanium compared to that on control titanium in osteoblasts from sham and OVX rats. Osteoblastic functions compromised by OVX were elevated to levels equivalent to or higher than those of sham-operated osteoblasts following culture on UV-treated titanium. The strength of in vivo bone-implant integration for UV-treated titanium was 80% higher than that of control titanium in OVX rats and even higher than that of control implants in sham-operated rats. Thus, UV-photofunctionalization effectively enhanced bone-implant integration in OVX rats to overcome post-menopausal osteoporosis-like conditions. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

17 pages, 4386 KiB

Open AccessArticle

A Newly Created Meso-, Micro-, and Nano-Scale Rough Titanium Surface Promotes Bone-Implant Integration

by Masakazu Hasegawa, Juri Saruta, Makoto Hirota, Takashi Taniyama, Yoshihiko Sugita, Katsutoshi Kubo, Manabu Ishijima, Takayuki Ikeda, Hatsuhiko Maeda and Takahiro Ogawa

Int. J. Mol. Sci. 2020, 21(3), 783; https://doi.org/10.3390/ijms21030783 - 25 Jan 2020

Cited by 58 | Viewed by 4590

Abstract

Titanium implants are the standard therapeutic option when restoring missing teeth and reconstructing fractured and/or diseased bone. However, in the 30 years since the advent of micro-rough surfaces, titanium’s ability to integrate with bone has not improved significantly. We developed a method to [...] Read more.

Titanium implants are the standard therapeutic option when restoring missing teeth and reconstructing fractured and/or diseased bone. However, in the 30 years since the advent of micro-rough surfaces, titanium’s ability to integrate with bone has not improved significantly. We developed a method to create a unique titanium surface with distinct roughness features at meso-, micro-, and nano-scales. We sought to determine the biological ability of the surface and optimize it for better osseointegration. Commercially pure titanium was acid-etched with sulfuric acid at different temperatures (120, 130, 140, and 150 °C). Although only the typical micro-scale compartmental structure was formed during acid-etching at 120 and 130 °C, meso-scale spikes (20–50 μm wide) and nano-scale polymorphic structures as well as micro-scale compartmental structures formed exclusively at 140 and 150 °C. The average surface roughness (Ra) of the three-scale rough surface was 6–12 times greater than that with micro-roughness only, and did not compromise the initial attachment and spreading of osteoblasts despite its considerably increased surface roughness. The new surface promoted osteoblast differentiation and in vivo osseointegration significantly; regression analysis between osteoconductivity and surface variables revealed these effects were highly correlated with the size and density of meso-scale spikes. The overall strength of osseointegration was the greatest when the acid-etching was performed at 140 °C. Thus, we demonstrated that our meso-, micro-, and nano-scale rough titanium surface generates substantially increased osteoconductive and osseointegrative ability over the well-established micro-rough titanium surface. This novel surface is expected to be utilized in dental and various types of orthopedic surgical implants, as well as titanium-based bone engineering scaffolds. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

15 pages, 3426 KiB

Open AccessArticle

Tuning of Titanium Microfiber Scaffold with UV-Photofunctionalization for Enhanced Osteoblast Affinity and Function

by Chika Iwasaki, Makoto Hirota, Miyuki Tanaka, Hiroaki Kitajima, Masako Tabuchi, Manabu Ishijima, Wonhee Park, Yoshihiko Sugita, Ken Miyazawa, Shigemi Goto, Takayuki Ikeda and Takahiro Ogawa

Int. J. Mol. Sci. 2020, 21(3), 738; https://doi.org/10.3390/ijms21030738 - 23 Jan 2020

Cited by 18 | Viewed by 2884

Abstract

Titanium (Ti) is an osteoconductive material that is routinely used as a bulk implant to fix and restore bones and teeth. This study explored the effective use of Ti as a bone engineering scaffold. Challenges to overcome were: (1) difficult liquid/cell infiltration into [...] Read more.

Titanium (Ti) is an osteoconductive material that is routinely used as a bulk implant to fix and restore bones and teeth. This study explored the effective use of Ti as a bone engineering scaffold. Challenges to overcome were: (1) difficult liquid/cell infiltration into Ti microfiber scaffolds due to the hydrophobic nature of Ti; and (2) difficult cell attachment on thin and curved Ti microfibers. A recent discovery of UV-photofunctionalization of Ti prompted us to examine its effect on Ti microfiber scaffolds. Scaffolds in disk form were made by weaving grade 4 pure Ti microfibers (125 µm diameter) and half of them were acid-etched to roughen the surface. Some of the scaffolds with original or acid-etched surfaces were further treated by UV light before cell culture. Ti microfiber scaffolds, regardless of the surface type, were hydrophobic and did not allow glycerol/water liquid to infiltrate, whereas, after UV treatment, the scaffolds became hydrophilic and immediately absorbed the liquid. Osteogenic cells from two different origins, derived from the femoral and mandibular bone marrow of rats, were cultured on the scaffolds. The number of cells attached to scaffolds during the early stage of culture within 24 h was 3–10 times greater when the scaffolds were treated with UV. The development of cytoplasmic projections and cytoskeletal, as well as the expression of focal adhesion protein, were exclusively observed on UV-treated scaffolds. Osteoblastic functional phenotypes, such as alkaline phosphatase activity and calcium mineralization, were 2–15 times greater on UV-treated scaffolds, with more pronounced enhancement on acid-etched scaffolds compared to that on the original scaffolds. These effects of UV treatment were associated with a significant reduction in atomic carbon on the Ti microfiber surfaces. In conclusion, UV treatment of Ti microfiber scaffolds tunes their physicochemical properties and effectively enhances the attachment and function of osteoblasts, proposing a new strategy for bone engineering. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

13 pages, 3829 KiB

Open AccessArticle

Computational Fluid Simulation of Fibrinogen around Dental Implant Surfaces

by Hiroaki Kitajima, Makoto Hirota, Toshinori Iwai, Kosuke Hamajima, Ryotaro Ozawa, Yuichiro Hayashi, Yasuharu Yajima, Masaki Iida, Toshiyuki Koizumi, Mitomu Kioi, Kenji Mitsudo and Takahiro Ogawa

Int. J. Mol. Sci. 2020, 21(2), 660; https://doi.org/10.3390/ijms21020660 - 19 Jan 2020

Cited by 16 | Viewed by 4849

Abstract

Ultraviolet treatment of titanium implants makes their surfaces hydrophilic and enhances osseointegration. However, the mechanism is not fully understood. This study hypothesizes that the recruitment of fibrinogen, a critical molecule for blood clot formation and wound healing, is influenced by the degrees of [...] Read more.

Ultraviolet treatment of titanium implants makes their surfaces hydrophilic and enhances osseointegration. However, the mechanism is not fully understood. This study hypothesizes that the recruitment of fibrinogen, a critical molecule for blood clot formation and wound healing, is influenced by the degrees of hydrophilicity/hydrophobicity of the implant surfaces. Computational fluid dynamics (CFD) implant models were created for fluid flow simulation. The hydrophilicity level was expressed by the contact angle between the implant surface and blood plasma, ranging from 5° (superhydrophilic), 30° (hydrophilic) to 50° and 70° (hydrophobic), and 100° (hydrorepellent). The mass of fibrinogen flowing into the implant interfacial zone (fibrinogen infiltration) increased in a time dependent manner, with a steeper slope for surfaces with greater hydrophilicity. The mass of blood plasma absorbed into the interfacial zone (blood plasma infiltration) was also promoted by the hydrophilic surfaces but it was rapid and non-time-dependent. There was no linear correlation between the fibrinogen infiltration rate and the blood plasma infiltration rate. These results suggest that hydrophilic implant surfaces promote both fibrinogen and blood plasma infiltration to their interface. However, the infiltration of the two components were not proportional, implying a selectively enhanced recruitment of fibrinogen by hydrophilic implant surfaces. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

13 pages, 2505 KiB

Open AccessArticle

Enhanced Osseointegration Capability of Poly(ether ether ketone) via Combined Phosphate and Calcium Surface-Functionalization

by Sunarso, Akira Tsuchiya, Riki Toita, Kanji Tsuru and Kunio Ishikawa

Int. J. Mol. Sci. 2020, 21(1), 198; https://doi.org/10.3390/ijms21010198 - 27 Dec 2019

Cited by 24 | Viewed by 3563

Abstract

Biomedical applications of poly(ether ether ketone) (PEEK) are hindered by its inherent bioinertness and lack of osseointegration capability. In the present study, to enhance osteogenic activity and, hence, the osseointegration capability of PEEK, we proposed a strategy of combined phosphate and calcium surface-functionalization, [...] Read more.

Biomedical applications of poly(ether ether ketone) (PEEK) are hindered by its inherent bioinertness and lack of osseointegration capability. In the present study, to enhance osteogenic activity and, hence, the osseointegration capability of PEEK, we proposed a strategy of combined phosphate and calcium surface-functionalization, in which ozone-gas treatment and wet chemistry were used for introduction of hydroxyl groups and modification of phosphate and/or calcium, respectively. Surface functionalization significantly elevated the surface hydrophilicity without changing the surface roughness or topography. The cell study demonstrated that immobilization of phosphate or calcium increased the osteogenesis of rat mesenchymal stem cells compared with bare PEEK, including cell proliferation, alkaline phosphatase activity, and bone-like nodule formation. Interestingly, further enhancement was observed for samples co-immobilized with phosphate and calcium. Furthermore, in the animal study, phosphate and calcium co-functionalized PEEK demonstrated significantly enhanced osseointegration, as revealed by a greater direct bone-to-implant contact ratio and bond strength between the bone and implant than unfunctionalized and phosphate-functionalized PEEK, which paves the way for the orthopedic and dental application of PEEK. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

14 pages, 5598 KiB

Open AccessArticle

Integration of Epigallocatechin Gallate in Gelatin Sponges Attenuates Matrix Metalloproteinase-Dependent Degradation and Increases Bone Formation

by Anqi Huang, Yoshitomo Honda, Peiqi Li, Tomonari Tanaka and Shunsuke Baba

Int. J. Mol. Sci. 2019, 20(23), 6042; https://doi.org/10.3390/ijms20236042 - 30 Nov 2019

Cited by 24 | Viewed by 3623

Abstract

Matrix metalloproteinase (MMP)-2 and MMP-9 are well-known gelatinases that disrupt the extracellular matrix, including gelatin. However, the advantages of modulating MMP expression in gelatin-based materials for applications in bone regenerative medicine have not been fully clarified. In this study, we examined the effects [...] Read more.

Matrix metalloproteinase (MMP)-2 and MMP-9 are well-known gelatinases that disrupt the extracellular matrix, including gelatin. However, the advantages of modulating MMP expression in gelatin-based materials for applications in bone regenerative medicine have not been fully clarified. In this study, we examined the effects of epigallocatechin gallate (EGCG), a major polyphenol catechin isolated from green tea, on MMP expression in gelatin sponges and its association with bone formation. Four gelatin sponges with or without EGCG were prepared and implanted into bone defects for up to 4 weeks. Histological and immunohistological staining were performed. Micro-computed tomography was used to estimate the bone-forming capacity of each sponge. Our results showed that EGCG integration attenuated MMP-2 (70.6%) and -9 expression (69.1%) in the 1 week group, increased residual gelatin (118.7%), and augmented bone formation (101.8%) in the 4 weeks group in critical-sized bone defects of rat calvaria compared with vacuum-heated gelatin sponges without EGCG. Moreover, vacuum-heated gelatin sponges with EGCG showed superior bone formation compared with other sponges. The results indicated that integration of EGCG in gelatin-based materials modulated the production and activity of MMP-2 and -9 in vivo, thereby enhancing bone-forming capacity. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

14 pages, 2722 KiB

Open AccessArticle

Diagnostic Cytokines and Comparative Analysis Secreted from Exfoliated Deciduous Teeth, Dental Pulp, and Bone Marrow Derived Mesenchymal Stem Cells for Functional Cell-Based Therapy

by Yoichi Yamada, Sayaka Nakamura-Yamada, Eri Umemura-Kubota and Shunsuke Baba

Int. J. Mol. Sci. 2019, 20(23), 5900; https://doi.org/10.3390/ijms20235900 - 24 Nov 2019

Cited by 30 | Viewed by 3736

Abstract

The aim of the study was to clarify the distinctive features of stem cells for effective cell-based therapy strategies in regenerative medicine. The expression levels of cytokines secreted from stem cells from exfoliated deciduous teeth (SHED), dental pulp stem cells (DPSCs), and bone [...] Read more.

The aim of the study was to clarify the distinctive features of stem cells for effective cell-based therapy strategies in regenerative medicine. The expression levels of cytokines secreted from stem cells from exfoliated deciduous teeth (SHED), dental pulp stem cells (DPSCs), and bone marrow derived mesenchymal stem cells (BMMSCs) were examined to identify the details of their characteristics. A total of 174 cytokines were analyzed using cytokine antibody array, and their expression levels were confirmed by an enzyme-linked immunosorbent assay. These results indicated that 11 cytokines that were related to tissue regeneration, including growth factors, chemokines, and inflammatory cytokines, were identical in SHED, DPSCs, and BMMSCs. The comparative analyses between SHED and BMMSCs revealed that hepatocyte growth factor (HGF), matrix metalloproteinase-3, and stromal cell derived factor 1 (SDF-1) were expressed 6.7-, 2.5-, and 2.1-fold higher, respectively, in SHEDs. HGF was also expressed 3.4-fold higher in DPSCs than BMMSCs. Monocyte chemoattractant protein-1, and-3 were expressed more strongly in BMMSCs. SHED contained significantly higher SDF-1 levels than DPSCs. The distinct cytokine secretion indicated that they had different character besides basic MSC features. This knowledge of diagnostic cytokines analysis secreted from SHED, DPSCs, and BMMSCs extends our understanding, and can provide a novel therapeutic paradigm shift for functional cell-based therapy. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

22 pages, 5786 KiB

Open AccessArticle

Cytoprotective Preconditioning of Osteoblast-Like Cells with N-Acetyl-L-Cysteine for Bone Regeneration in Cell Therapy

by Masahiro Yamada, Jun Watanabe, Takeshi Ueno, Takahiro Ogawa and Hiroshi Egusa

Int. J. Mol. Sci. 2019, 20(20), 5199; https://doi.org/10.3390/ijms20205199 - 20 Oct 2019

Cited by 17 | Viewed by 3759

Abstract

Oxidative stress hinders tissue regeneration in cell therapy by inducing apoptosis and dysfunction in transplanted cells. N-acetyl-L-cysteine (NAC) reinforces cellular antioxidant capabilities by increasing a major cellular endogenous antioxidant molecule, glutathione, and promotes osteogenic differentiation. This study investigates the effects [...] Read more.

Oxidative stress hinders tissue regeneration in cell therapy by inducing apoptosis and dysfunction in transplanted cells. N-acetyl-L-cysteine (NAC) reinforces cellular antioxidant capabilities by increasing a major cellular endogenous antioxidant molecule, glutathione, and promotes osteogenic differentiation. This study investigates the effects of pretreatment of osteoblast-like cells with NAC on oxidative stress-induced apoptosis and dysfunction and bone regeneration in local transplants. Rat femur bone marrow-derived osteoblast-like cells preincubated for 3 h with and without 5 mM NAC were cultured in a NAC-free osteogenic differentiation medium with continuous exposure to 50 μM hydrogen peroxide to induce oxidative stress. NAC preincubation prevented disruption of intracellular redox balance and alleviated apoptosis and negative impact on osteogenic differentiation, even under oxidative stress. Autologous osteoblast-like cells with and without NAC pretreatment in a collagen sponge vehicle were implanted in critical-size defects in rat femurs. In the third week, NAC-pretreated cells yielded complete defect closure with significantly matured lamellar bone tissue in contrast with poor bone healing by cells without pretreatment. Cell-tracking analysis demonstrated direct bone deposition by transplanted cells pretreated with NAC. Pretreatment of osteoblast-like cells with NAC enhances bone regeneration in local transplantation by preventing oxidative stress-induced apoptosis and dysfunction at the transplanted site. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

23 pages, 6910 KiB

Open AccessArticle

Off-Stoichiometric Reactions at the Cell–Substrate Biomolecular Interface of Biomaterials: In Situ and Ex Situ Monitoring of Cell Proliferation, Differentiation, and Bone Tissue Formation

by Giuseppe Pezzotti, Tetsuya Adachi, Francesco Boschetto, Wenliang Zhu, Matteo Zanocco, Elia Marin, B. Sonny Bal and Bryan J. McEntire

Int. J. Mol. Sci. 2019, 20(17), 4080; https://doi.org/10.3390/ijms20174080 - 21 Aug 2019

Cited by 9 | Viewed by 3681

Abstract

The availability of osteoinductive biomaterials has encouraged new therapies in bone regeneration and has potentially triggered paradigmatic shifts in the development of new implants in orthopedics and dentistry. Among several available synthetic biomaterials, bioceramics have gained attention for their ability to induce mesenchymal [...] Read more.

The availability of osteoinductive biomaterials has encouraged new therapies in bone regeneration and has potentially triggered paradigmatic shifts in the development of new implants in orthopedics and dentistry. Among several available synthetic biomaterials, bioceramics have gained attention for their ability to induce mesenchymal cell differentiation and successive bone formation when implanted in the human body. However, there is currently a lack of understanding regarding the fundamental biochemical mechanisms by which these materials can induce bone formation. Phenomenological studies of retrievals have clarified the final effect of bone formation, but have left the chemical interactions at the cell–material interface uncharted. Accordingly, the knowledge of the intrinsic material properties relevant for osteoblastogenesis and osteoinduction remains incomplete. Here, we systematically monitored in vitro the chemistry of mesenchymal cell metabolism and the ionic exchanges during osteoblastogenesis on selected substrates through conventional biological assays as well as via in situ and ex situ spectroscopic techniques. Accordingly, the chemical behavior of different bioceramic substrates during their interactions with mesenchymal cells could be unfolded and compared with that of biomedical titanium alloy. Our goal was to clarify the cascade of chemical equations behind the biological processes that govern osteoblastogenic effects on different biomaterial substrates. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

15 pages, 3084 KiB

Open AccessArticle

Disproportionate Effect of Sub-Micron Topography on Osteoconductive Capability of Titanium

by Juri Saruta, Nobuaki Sato, Manabu Ishijima, Takahisa Okubo, Makoto Hirota and Takahiro Ogawa

Int. J. Mol. Sci. 2019, 20(16), 4027; https://doi.org/10.3390/ijms20164027 - 18 Aug 2019

Cited by 41 | Viewed by 3871

Abstract

Titanium micro-scale topography offers excellent osteoconductivity and bone–implant integration. However, the biological effects of sub-micron topography are unknown. We compared osteoblastic phenotypes and in vivo bone and implant integration abilities between titanium surfaces with micro- (1–5 µm) and sub-micro-scale (0.1–0.5 µm) compartmental structures [...] Read more.

Titanium micro-scale topography offers excellent osteoconductivity and bone–implant integration. However, the biological effects of sub-micron topography are unknown. We compared osteoblastic phenotypes and in vivo bone and implant integration abilities between titanium surfaces with micro- (1–5 µm) and sub-micro-scale (0.1–0.5 µm) compartmental structures and machined titanium. The calculated average roughness was 12.5 ± 0.65, 123 ± 6.15, and 24 ± 1.2 nm for machined, micro-rough, and sub-micro-rough surfaces, respectively. In culture studies using bone marrow-derived osteoblasts, the micro-rough surface showed the lowest proliferation and fewest cells attaching during the initial stage. Calcium deposition and expression of osteoblastic genes were highest on the sub-micro-rough surface. The bone–implant integration in the Sprague–Dawley male rat femur model was the strongest on the micro-rough surface. Thus, the biological effects of titanium surfaces are not necessarily proportional to the degree of roughness in osteoblastic cultures or in vivo. Sub-micro-rough titanium ameliorates the disadvantage of micro-rough titanium by restoring cell attachment and proliferation. However, bone integration and the ability to retain cells are compromised due to its lower interfacial mechanical locking. This is the first report on sub-micron topography on a titanium surface promoting osteoblast function with minimal osseointegration. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

11 pages, 6082 KiB

Open AccessArticle

Extracellular Matrix Induces Periodontal Ligament Reconstruction In Vivo

by Naoko Nakamura, Ai Ito, Tsuyoshi Kimura and Akio Kishida

Int. J. Mol. Sci. 2019, 20(13), 3277; https://doi.org/10.3390/ijms20133277 - 3 Jul 2019

Cited by 26 | Viewed by 6853

Abstract

One of the problems in dental implant treatment is the lack of periodontal ligament (PDL), which supports teeth, prevents infection, and transduces sensations such as chewiness. The objective of the present study was to develop a decellularized PDL for supporting an artificial tooth. [...] Read more.

One of the problems in dental implant treatment is the lack of periodontal ligament (PDL), which supports teeth, prevents infection, and transduces sensations such as chewiness. The objective of the present study was to develop a decellularized PDL for supporting an artificial tooth. To this end, we prepared mouse decellularized mandible bone with a PDL matrix by high hydrostatic pressure and DNase and detergent treatments and evaluated its reconstruction in vivo. After tooth extraction, the decellularized mandible bone with PDL matrix was implanted under the subrenal capsule in rat and observed that host cells migrated into the matrix and oriented along the PDL collagen fibers. The extracted decellularized tooth and de- and re-calcified teeth, which was used as an artificial tooth model, were re-inserted into the decellularized mandible bone and implanted under the subrenal capsule in rat. The reconstructed PDL matrix for the extracted decellularized tooth resembled the decellularized mandible bone without tooth extraction. This demonstrates that decellularized PDL matrix can reconstruct PDL tissue by controlling host cell migration, which could serve as a novel periodontal treatment approach. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

21 pages, 8810 KiB

Open AccessArticle

Effect of Strontium Substitution on the Physicochemical Properties and Bone Regeneration Potential of 3D Printed Calcium Silicate Scaffolds

by Yung-Cheng Chiu, Ming-You Shie, Yen-Hong Lin, Alvin Kai-Xing Lee and Yi-Wen Chen

Int. J. Mol. Sci. 2019, 20(11), 2729; https://doi.org/10.3390/ijms20112729 - 3 Jun 2019

Cited by 43 | Viewed by 4778

Abstract

In this study, we synthesized strontium-contained calcium silicate (SrCS) powder and fabricated SrCS scaffolds with controlled precise structures using 3D printing techniques. SrCS scaffolds were shown to possess increased mechanical properties as compared to calcium silicate (CS) scaffolds. Our results showed that SrCS [...] Read more.

In this study, we synthesized strontium-contained calcium silicate (SrCS) powder and fabricated SrCS scaffolds with controlled precise structures using 3D printing techniques. SrCS scaffolds were shown to possess increased mechanical properties as compared to calcium silicate (CS) scaffolds. Our results showed that SrCS scaffolds had uniform interconnected macropores (~500 µm) with a compressive strength 2-times higher than that of CS scaffolds. The biological behaviors of SrCS scaffolds were assessed using the following characteristics: apatite-precipitating ability, cytocompatibility, proliferation, and osteogenic differentiation of human mesenchymal stem cells (MSCs). With CS scaffolds as controls, our results indicated that SrCS scaffolds demonstrated good apatite-forming bioactivity with sustained release of Si and Sr ions. The in vitro tests demonstrated that SrCS scaffolds possessed excellent biocompatibility which in turn stimulated adhesion, proliferation, and differentiation of MSCs. In addition, the SrCS scaffolds were able to enhance MSCs synthesis of osteoprotegerin (OPG) and suppress macrophage colony-stimulating factor (M-CSF) thus disrupting normal bone homeostasis which led to enhanced bone formation over bone resorption. Implanted SrCS scaffolds were able to promote new blood vessel growth and new bone regeneration within 4 weeks after implantation in critical-sized rabbit femur defects. Therefore, it was shown that 3D printed SrCS scaffolds with specific controllable structures can be fabricated and SrCS scaffolds had enhanced mechanical property and osteogenesis behavior which makes it a suitable potential candidate for bone regeneration. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

15 pages, 9792 KiB

Open AccessArticle

Optimized Surface Characteristics and Enhanced in Vivo Osseointegration of Alkali-Treated Titanium with Nanonetwork Structures

by Yuhao Zeng, Yuanyuan Yang, Luyuan Chen, Derong Yin, Honghao Zhang, Yuichiro Tashiro, Shihoko Inui, Tetsuji Kusumoto, Hiroshi Nishizaki, Tohru Sekino, Joji Okazaki and Satoshi Komasa

Int. J. Mol. Sci. 2019, 20(5), 1127; https://doi.org/10.3390/ijms20051127 - 5 Mar 2019

Cited by 19 | Viewed by 3756

Abstract

Alkali-treated titanium (Ti) with a porous, homogeneous, and uniform nanonetwork structure (TNS) that enables establishment of a more rapid and firmer osteointegration than titanium has recently been reported. However, the mechanisms underlying the enhanced osteogenic activity on TNS remains to be elucidated. This [...] Read more.

Alkali-treated titanium (Ti) with a porous, homogeneous, and uniform nanonetwork structure (TNS) that enables establishment of a more rapid and firmer osteointegration than titanium has recently been reported. However, the mechanisms underlying the enhanced osteogenic activity on TNS remains to be elucidated. This study aimed to evaluate the surface physicochemical properties of Ti and TNS, and investigate osteoinduction and osteointegration in vivo. Surface characteristics were evaluated using scanning electron microscopy (SEM), scanning probe microscopy (SPM), and X-ray photoelectron spectrometry (XPS), and the surface electrostatic force of TNS was determined using solid zeta potential. This study also evaluated the adsorption of bovine serum albumin (BSA) and human plasma fibronectin (HFN) on Ti and TNS surfaces using quartz crystal microbalance (QCM) sensors, and apatite formation on Ti and TNS surfaces was examined using a simulated body fluid (SBF) test. Compared with Ti, the newly developed TNS enhanced BSA and HFN absorbance capacity and promoted apatite formation. Furthermore, TNS held less negative charge than Ti. Notably, sequential fluorescence labeling and microcomputed tomography assessment indicated that TNS screws implanted into rat femurs exhibited remarkably enhanced osteointegration compared with Ti screws. These results indicate that alkali-treated titanium implant with a nanonetwork structure has considerable potential for future clinical applications in dentistry and orthopedics. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

10 pages, 2703 KiB

Open AccessCommunication

Acidic Pre-Conditioning Enhances the Stem Cell Phenotype of Human Bone Marrow Stem/Progenitor Cells

by Yuri Hazehara-Kunitomo, Emilio Satoshi Hara, Mitsuaki Ono, Kyaw Thu Aung, Keiko Komi, Hai Thanh Pham, Kentaro Akiyama, Masahiro Okada, Toshitaka Oohashi, Takuya Matsumoto and Takuo Kuboki

Int. J. Mol. Sci. 2019, 20(5), 1097; https://doi.org/10.3390/ijms20051097 - 4 Mar 2019

Cited by 31 | Viewed by 4198

Abstract

A deeper understanding of the detailed mechanism of in vivo tissue healing is necessary for the development of novel regenerative therapies. Among several external factors, environmental pH is one of the crucial parameters that greatly affects enzyme activity and cellular biochemical reactions involving [...] Read more.

A deeper understanding of the detailed mechanism of in vivo tissue healing is necessary for the development of novel regenerative therapies. Among several external factors, environmental pH is one of the crucial parameters that greatly affects enzyme activity and cellular biochemical reactions involving tissue repair and homeostasis. In this study, in order to analyze the microenvironmental conditions during bone healing, we first measured the pH in vivo at the bone healing site using a high-resolution fiber optic pH microsensor directly in femur defects and tooth extraction sockets. The pH was shown to decrease from physiological 7.4 to 6.8 during the initial two days of healing (inflammatory phase). In the same initial stages of the inflammatory phase of the bone healing process, mesenchymal stem cells (MSCs) are known to migrate to the healing site to contribute to tissue repair. Therefore, we investigated the effect of a short-term acidic (pH 6.8) pre-treatment on the stemness of bone marrow-derived MSCs (BMSCs). Interestingly, the results showed that pre-treatment of BMSCs with acidic pH enhances the expression of stem cell markers (OCT-4, NANOG, SSEA-4), as well as cell viability and proliferation. On the other hand, acidic pH decreased BMSC migration ability. These results indicate that acidic pH during the initial stages of bone healing is important to enhance the stem cell properties of BMSCs. These findings may enable the development of novel methods for optimization of stem cell function towards tissue engineering or regenerative medicine. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

11 pages, 5184 KiB

Open AccessCommunication

Vascularized Bone-Mimetic Hydrogel Constructs by 3D Bioprinting to Promote Osteogenesis and Angiogenesis

by Takahisa Anada, Chi-Chun Pan, Alexander M. Stahl, Satomi Mori, Junji Fukuda, Osamu Suzuki and Yunzhi Yang

Int. J. Mol. Sci. 2019, 20(5), 1096; https://doi.org/10.3390/ijms20051096 - 4 Mar 2019

Cited by 126 | Viewed by 8875

Abstract

Bone is a highly vascularized tissue with a unique and complex structure. Long bone consists of a peripheral cortical shell containing a network of channels for vascular penetration and an inner highly vascularized bone marrow space. Bioprinting is a powerful tool to enable [...] Read more.

Bone is a highly vascularized tissue with a unique and complex structure. Long bone consists of a peripheral cortical shell containing a network of channels for vascular penetration and an inner highly vascularized bone marrow space. Bioprinting is a powerful tool to enable rapid and precise spatial patterning of cells and biomaterials. Here we developed a two-step digital light processing technique to fabricate a bone-mimetic 3D hydrogel construct based on octacalcium phosphate (OCP), spheroids of human umbilical vein endothelial cells (HUVEC), and gelatin methacrylate (GelMA) hydrogels. The bone-mimetic 3D hydrogel construct was designed to consist of a peripheral OCP-containing GelMA ring to mimic the cortical shell, and a central GelMA ring containing HUVEC spheroids to mimic the bone marrow space. We further demonstrate that OCP, which is evenly embedded in the GelMA, stimulates the osteoblastic differentiation of mesenchymal stem cells. We refined the design of a spheroid culture device to facilitate the rapid formation of a large number of HUVEC spheroids, which were embedded into different concentrations of GelMA hydrogels. It is shown that the concentration of GelMA modulates the extent of formation of the capillary-like structures originating from the HUVEC spheroids. This cell-loaded hydrogel-based bone construct with a biomimetic dual ring structure can be potentially used for bone tissue engineering. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

12 pages, 10325 KiB

Open AccessArticle

Osseointegration of Alkali-Modified NANOZR Implants: An In Vivo Study

by Satoshi Komasa, Mariko Nishizaki, Honghao Zhang, Seiji Takao, Derong Yin, Chisato Terada, Yasuyuki Kobayashi, Tetsuji Kusumoto, Shigeki Yoshimine, Hiroshi Nishizaki, Joji Okazaki and Luyuan Chen

Int. J. Mol. Sci. 2019, 20(4), 842; https://doi.org/10.3390/ijms20040842 - 15 Feb 2019

Cited by 15 | Viewed by 3084

Abstract

Ingredients and surface modification methods are being continually developed to improve osseointegration of dental implants and reduce healing times. In this study, we demonstrate in vitro that, by applying concentrated alkali treatment to NANOZR with strong bending strength and fracture toughness, a significant [...] Read more.

Ingredients and surface modification methods are being continually developed to improve osseointegration of dental implants and reduce healing times. In this study, we demonstrate in vitro that, by applying concentrated alkali treatment to NANOZR with strong bending strength and fracture toughness, a significant improvement in the bone differentiation of rat bone marrow cells can be achieved. We investigated the influence of materials modified with this treatment in vivo, on implanted surrounding tissues using polychrome sequential fluorescent labeling and micro-computer tomography scanning. NANOZR implant screws in the alkali-treated group and the untreated group were evaluated after implantation in the femur of Sprague–Dawley male rats, indicating that the amount of new bone in the alkali-modified NANOZR was higher than that of unmodified NANOZR. Alkali-modified NANOZR implants proved to be useful for the creation of new implant materials. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Figure 1

16 pages, 4190 KiB

Open AccessArticle

Osteogenesis of Multipotent Progenitor Cells using the Epigallocatechin Gallate-Modified Gelatin Sponge Scaffold in the Rat Congenital Cleft-Jaw Model

by Satoshi Sasayama, Tomoya Hara, Tomonari Tanaka, Yoshitomo Honda and Shunsuke Baba

Int. J. Mol. Sci. 2018, 19(12), 3803; https://doi.org/10.3390/ijms19123803 - 29 Nov 2018

Cited by 28 | Viewed by 4580

Abstract

Cost-effective and functionalized scaffolds are in high demand for stem-cell-based regenerative medicine to treat refractory bone defects in craniofacial abnormalities and injuries. One potential strategy is to utilize pharmacological and cost-effective plant polyphenols and biocompatible proteins, such as gelatin. Nevertheless, the use of [...] Read more.

Cost-effective and functionalized scaffolds are in high demand for stem-cell-based regenerative medicine to treat refractory bone defects in craniofacial abnormalities and injuries. One potential strategy is to utilize pharmacological and cost-effective plant polyphenols and biocompatible proteins, such as gelatin. Nevertheless, the use of chemically modified proteins with plant polyphenols in this strategy has not been standardized. Here, we demonstrated that gelatin chemically modified with epigallocatechin gallate (EGCG), the major catechin isolated from green tea, can be a useful material to induce bone regeneration in a rat congenial cleft-jaw model in vivo when used with/without adipose-derived stem cells or dedifferentiated fat cells. Vacuum-heated gelatin sponges modified with EGCG (vhEGCG-GS) induced superior osteogenesis from these two cell types compared with vacuum-heated gelatin sponges (vhGS). The EGCG-modification converted the water wettability of vhGS to a hydrophilic property (contact angle: 110° to 3.8°) and the zeta potential to a negative surface charge; the modification enhanced the cell adhesion property and promoted calcium phosphate precipitation. These results suggest that the EGCG-modification with chemical synthesis can be a useful platform to modify the physicochemical property of gelatin. This alteration is likely to provide a preferable microenvironment for multipotent progenitor cells, inducing superior bone formation in vivo. Full article

(This article belongs to the Special Issue Functional Materials for Bone Regeneration: Biomaterials and Cells)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Functional Materials for Bone Regeneration: Biomaterials and Cells

Share This Special Issue

Special Issue Editors

Special Issue Information

Benefits of Publishing in a Special Issue

Published Papers (27 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI