| 1. |
- Ichioka, Yuki, et al.
(author)
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Epigenetic changes of osteoblasts in response to titanium surface characteristics.
- 2021
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In: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 109:2, s. 170-180
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Journal article (peer-reviewed)abstract
- We aimed to investigate the influence of titanium surface characteristics on epigenetic mechanisms and DNA damage/repair pathways. Osteoblast-like cells (MG63) were incubated on glass, smooth titanium, and minimally rough titanium discs, respectively, for 0, 1, 6, and 24hr. The presence of double-stranded DNA damage (γH2AX), DNA repair (Chk2), and epigenetic markers (AcH3 & DNMT1) were investigated using immunofluorescence. There were no Chk2-positive cells on the minimally rough titanium surfaces at all-time points, in comparison to glass and smooth titanium. Total γH2AX-positive cells on minimally rough titanium gradually decreased as incubation time increased, on the contrary to smooth titanium. Minimally rough titanium surfaces induced cytoplasmic staining of DNMT1 up to 99% at 24hr. For epigenetic markers related to the DNA damage/repair pathway, minimally rough titanium surfaces showed the lower percentage of AcH3-positive cells compared to glass and smooth titanium surface. The findings in the current study show that titanium surface characteristics indeed influence DNA damage and the DNA repair pathway, including epigenetic factors.
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| 2. |
- Malekzadeh, Benoosh, et al.
(author)
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Effects of locally administered insulin on bone formation in non-diabetic rats
- 2013
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In: Journal of Biomedical Materials Research. Part A. - : John Wiley & Sons. - 1549-3296 .- 1552-4965. ; 101A:1, s. 132-137
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Journal article (peer-reviewed)abstract
- The possibility to control bone formation would be favorable in many areas of medicine, where bone defects is still a major challenge. Insulin has been suggested to exert both systemic and local anabolic effects in bone tissues. This raised the question whether locally administrated insulin could provide new therapeutic strategies for patients with local bone defects and impaired bone healing. The aim of this study was to evaluate bone formation in non-diabetic rats when local insulin is administered. This study differs from previous reports in two aspects: the use of non-diabetic animals and locally administered insulin. Twenty-four implants were inserted into 12 rats-one insulin-coated and one control-in each tibia for four weeks. Interferometry and histomorphometry were used to evaluate the surface topography and bone formation, respectively. Results demonstrated no significant changes in surface topography after insulin immobilization. Histomorphometry revealed significantly more bone around the insulin-coated implants (BA) (p = 0.005) and a similar amount of bone at the implant surface (BIC) (p = 0.117) compared with the controls. It was concluded that locally administered insulin from a titanium implant surface has the potential to increase bone formation not only in diabetic subjects but also in non-diabetic subjects.
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| 3. |
- Öhrnell Malekzadeh, Behnosh, et al.
(author)
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Effects of implant-delivered insulin on bone formation in osteoporotic rats
- 2018
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In: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 106:9, s. 2472-80
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Journal article (peer-reviewed)abstract
- © 2018 Wiley Periodicals, Inc. Osteoporosis is a major cause of age-related fractures. Healing complications in osteoporotic patients are often associated with increased mortality and morbidity. Stimulation of the implant-adjacent bone could be beneficial in terms of the surgical outcome. Over the past decade, numerous investigations have implicated insulin in normal bone growth, and recent studies have described the advantages of administering insulin locally to increase bone formation. Therefore, we hypothesized that insulin-coated titanium implants would increase bone formation in osteoporotic animals. The aim of this study was to evaluate the effects of insulin delivered from an implant surface on bone-related gene expression and bone formation in osteoporotic rats. Characterizations of the surfaces of insulin-coated and control implants were performed using ellipsometry and interferometry. Forty ovariectomized and four healthy Sprague Dawley rats were used and implants were inserted in the tibias. The systemic effect of insulin was assessed by measuring the blood glucose levels and total body weight. The animals were sacrificed either 1 day or 3 weeks postimplantation. Implant-adherent cells were analyzed by quantitative real-time PCR, and the bone adjacent to the implants was examined by microcomputed tomography and histomorphometry. The insulin-coated implants had no systemic effects. The insulin-coated samples demonstrated significantly lower expression of the gene for interleukin 1β (p=0.019) at 1 day, and significantly exhibited more periosteal callus (p=0.029) at 3 weeks. Locally delivered insulin has potential for promoting bone formation and it exerts potentially anti-inflammatory effects in osteoporotic rats.
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