Denise Seabold

Implant Surface Roughness Affects Osteoblast Gene Expression

The transcription factor Cbfa1 regulates osteoblast differentiation and expression of genes necessary for the development of a mineralized phenotype. The purpose of this study was to determine if Cbfa1 and BSPII gene expression are influenced by implant surface microtopography. Osteoblasts were cultured on 600-grit (grooved) or sandblasted (roughened) cpTi implant discs. Mineralization was evaluated by Alizarin-Red-S staining. Real Time PCR was used for quantitative analysis of Cbfa1 and BSPII gene expression. Enhanced mineralization was seen in osteoblasts grown on roughened implant surfaces relative to tissue culture plastic. Real Time PCR showed significant (P < 0.05) increases in Cbfa1 gene expression in cells grown on roughened, as compared with grooved, implant surfaces. BSPII gene expression was also increased on rough surfaces in the UMR cells, but was reduced in the rat calvarial osteoblast cultures. These results suggest that osteoblast gene expression and mineralization are affected by roughened implant surface microtopographies during osseointegration of dental implants.

Apatite/Amelogenin Coating on Titanium Promotes Osteogenic Gene Expression

Osteoblast differentiation and extracellular matrix production are pivotal processes for implant osseointegration or bone tissue engineering. We hypothesized that a biomimetic coating on titanium surfaces, consisting of apatite and amelogenin, would promote such processes. Human Embryonic Palatal Mesenchymal pre-osteoblasts were used as a model for the evaluation of cell adhesion and spreading patterns, as well as mRNA expression of certain osteoblastic gene products. Real-time PCR showed significant (p < 0.05) increase in expression of type I collagen, alkaline phosphatase, and osteocalcin from cells grown on titanium with an apatite/amelogenin composite, as compared with that from cells grown on a pure titanium or apatite coating only. Osteocalcin expression was specifically stimulated by amelogenin added to the culture media. Enhanced attachment and cell spreading were also observed. The biomimetic coating promoting cell adhesion and osteoblast differentiation may have great potential for future dental and biomedical applications.

Integrin-associated tyrosine kinase FAK affects Cbfa1 expression

Following cell adhesion, focal adhesion kinase (FAK) autophosphorylates on tyrosine and regulates intracellular signaling cascades that regulate cell growth and differentiation. The hypothesis of this study was FAK mediates osteoblast differentiation dependent Cbfa1 expression. Slowly mineralizing UI and rapidly mineralizing UMR‐106‐01 BSP osteoblasts formed focal adhesions; however, the level of FAK in UI focal adhesions was less than that seen in BSP cells. UI cultures had less FAK expression (p < 0.05) along with elevated levels of FAK phosphotyrosine in comparison to rapidly mineralizing BSP cultures. Mineralization decreased in a dose‐dependent manner in response to Herbimycin A, a tyrosine kinase inhibitor. Overexpression of FAK in UI cells led to a fourfold increase in Cbfa1 gene expression (p < 0.02), and an increase in Cbfa1 protein expression. These results suggest that the integrin‐associated tyrosine kinase FAK contributes to the regulation of the osteoblast differentiation in part through the regulation of Cbfa1 expression.

Gene-Activated Titanium Surfaces Promote In Vitro Osteogenesis.

PURPOSE Commercially pure titanium (CpTi) and its alloys possess favorable mechanical and biologic properties for use as implants in orthopedics and dentistry. However, failures in osseointegration still exist and are common in select individuals with risk factors such as smoking. Therefore, in this study, a proposal was made to enhance the potential for osseointegration of CpTi discs by coating their surfaces with nanoplexes comprising polyethylenimine (PEI) and plasmid DNA (pDNA) encoding bone morphogenetic protein-2 (pBMP-2). MATERIALS AND METHODS The nanoplexes were characterized for size and surface charge with a range of N/P ratios (the molar ratio of amine groups of PEI to phosphate groups in pDNA backbone). CpTi discs were surface characterized for morphology and composition before and after nanoplex coating using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD). The cytotoxicity and transfection ability of CpTi discs coated with nanoplexes of varying N/P ratios in human bone marrow-derived mesenchymal stem cells (BMSCs) was measured via MTS assays and flow cytometry, respectively. RESULTS The CpTi discs coated with nanoplexes prepared at an N/P ratio of 10 (N/P-10) were considered optimal, resulting in 75% cell viability and 14% transfection efficiency. Enzyme-linked immunosorbent assay results demonstrated a significant enhancement in BMP-2 protein secretion by BMSCs 7 days posttreatment with PEI/pBMP-2 nanoplexes (N/P-10) compared to the controls, and real-time PCR data demonstrated that the BMSCs treated with PEI/pBMP-2 nanoplex-coated CpTi discs resulted in an enhancement of Runx-2, alkaline phosphatase, and osteocalcin gene expressions on day 7 posttreatment. In addition, these BMSCs demonstrated enhanced calcium deposition on day 30 posttreatment as determined by qualitative (alizarin red staining) and quantitative (atomic absorption spectroscopy) assays. CONCLUSION It can be concluded that PEI/pBMP-2 nanoplex (N/P-10)-coated CpTi discs have the potential to induce osteogenesis and enhance osseointegration.

A randomized trial using telehealth technology to link caregivers with dementia care experts for in‐home caregiving support: FamTechCare protocol

The number of persons with dementia (PWD) in the United States is expected to reach 16 million by 2050. Due to the behavioral and psychological symptoms of dementia, caregivers face challenging in-home care situations that lead to a range of negative health outcomes such as anxiety and depression for the caregivers and nursing home placement for PWD. Supporting Family Caregivers with Technology for Dementia Home Care (FamTechCare) is a multisite randomized controlled trial evaluating the effects of a telehealth intervention on caregiver well-being and PWD behavioral symptoms. The FamTechCare intervention provides individualized dementia-care strategies to in-home caregivers based on video recordings that the caregiver creates of challenging care situations. A team of dementia care experts review videos submitted by caregivers and provide interventions to improve care weekly for the experimental group. Caregivers in the control group receive feedback for improving care based on a weekly phone call with the interventionist and receive feedback on their videos at the end of the 3-month study. Using linear mixed modeling, we will compare experimental and control group outcomes (PWD behavioral symptoms and caregiver burden) after 1 and 3 months. An exploratory descriptive design will identify a typology of interventions for telehealth support for in-home dementia caregivers. Finally, the cost for FamTechCare will be determined and examined in relation to hypothesized effects on PWD behavioral symptoms, placement rates, and caregiver burden. This research will provide the foundation for future research for telehealth interventions with this population, especially for families in rural or remote locations.