Tailoring bisphosphonate-doped titanium films to optimally couple cellular responses and antibacterial activity for biomedical applications.

Titanium (Ti) is widely utilized as an implant material; nonetheless, its integration with bone tissue faces limitations due to a patient's comorbidities. To address this challenge, we employed a strategic approach involving the growth of thin films by spin-coating and surface functionalization with etidronate (ETI), alendronate (ALE), and risedronate (RIS). Our methodology involved coating of Ti cp IV disks with thin films of TiO2, hydroxyapatite (HA), and their combinations (1:1 and 1:2 v/v), followed by surface functionalization with ETI, ALE, and RIS. Bisphosphonate-doped films were evaluated in terms of surface morphology and physical-chemical properties by techniques such as electron microscopy, confocal microscopy, and x-ray photoelectron spectroscopy. The antibacterial potential of bisphosphonates alone or functionalized onto the Ti surface was tested against Staphylococcus aureus biofilms. Primary human bone mesenchymal stem cells were used to determine in vitro cell metabolism and mineralization. Although RIS alone did not demonstrate any antibacterial effect as verified by minimum inhibitory concentration assay, when Ti surfaces were functionalized with RIS, partial inhibition of Staphylococcus aureus growth was noted, probably because of the physical-chemical surface properties. Furthermore, samples comprising TiO2/HA (1:1 and 1:2 v/v) showcased an enhancement in the metabolism of nondifferentiated cells and can potentially enhance the differentiation of osteoblastic precursors. All samples demonstrated cell viability higher than 80%. Addition of hydroxyapatite and presence of bisphosphonates increase the metabolic activity and the mineralization of human bone mesenchymal cells. While these findings hold promise, it is necessary to conduct further studies to evaluate the system's performance in vivo and ensure its long-term safety. This research marks a significant stride toward optimizing the efficacy of titanium implants through tailored surface modifications.

Immune response characterization of primary gingival fibroblasts from Grade C periodontitis patients.

BACKGROUND: Grade C, Stage 3-4 Periodontitis (Perio4C) is a rapidly destructive disease caused by an unequilibrated immune response that starts after the primary contact of the periodontopathogens with the gingival tissue. However, it is still unclear how this imbalanced response initiates and what is the role of the connective tissue cells in the progression of this disease. Thus, this study aims to assess the local immune response of Perio4C patients through the exposure of primary gingival fibroblast cells (GFs) with Aggregatibacter actinomycetemcomitans protein extract (AaPE) and the quantification of the inflammatory cytokines interleukin (IL)-4, IL-17, tumor necrosis factor (TNF)-α, IL-1ß, interferon (IFN)-γ, and IL-10 super-family members (IL-10, IL-19, and IL-24) secreted by them. METHODS: Gingival biopsies from nine periodontally health (PH) and eight Perio4C patients were harvested, and the primary culture of GFs was obtained. The cells were exposed to AaPE (5 and 20 µg/ml) and 12-myristate 13-phorbol acetate and ionomycin - calcium salt (PMA). The supernatant was collected after 1.5 and 3 h, and a cytokine panel was evaluated. RESULTS: Clustering analysis indicated dissimilar and stimuli-dependent cytokine production between Perio4C and PH subjects. Perio4C GFs presented lower production of IL-4, TNF-α, IFN-γ, IL-17, IL-10, IL-24, and IL-19, while IL-1ß levels were similar to the PH group, leading to a disruption in the pro-/anti-inflammatory cytokine ratio (p < 0.05). IL-1ß and IL-10 super-family were the most discriminative representants for PH and Perio4C, respectively. CONCLUSION: GFs from individuals with Perio4C tended to hypo-respond to stimulation with AaPE, producing lower concentrations of some pro- and anti-inflammatory molecules, trending to develop a pro-inflammatory extracellular environment.

IL10 promoter rs6667202 polymorphism is functional in health but not in grade c periodontitis patients: A pilot study.

BACKGROUND AND OBJECTIVE: Previous studies have demonstrated an association between the IL10 promoter rs6667202 (C > A) single-nucleotide polymorphism (SNP) and grade C, stage 3 or 4 periodontitis (Perio4C) in the Brazilian population, where the altered A allele was detected more frequently in these patients. However, no functional analysis of this variation has yet been performed. Thus, the objective of this preliminary study was to evaluate the functionality of rs6667202 in gingival fibroblasts (GFs) of individuals with Perio4C and with periodontal health (PH) stimulated with Aggregatibacter actinomycetencomitans protein extract (AaPE). METHODS: Patients with PH and Perio4C were segregated according to their genotype (AA, AC, or CC), and a biopsy was performed to establish the culture of the GFs. After GFs exposure to AaPE at 5 µg/ml for 1.5 h, RNA was extracted to analyze IL10 expression by qPCR. Aliquots of the cell's supernatant were subjected to immunoenzymatic analysis (MAGpix) to detect interleukin-10 (IL-10). RESULTS: In PH, the genotypes AA and AC are related to less expression of IL10 (p = 0.027 and p < 0.0001) and less production of IL-10 (p = 0.002 and p = 0.001), when compared to CC. In Perio4C, there was no statistical difference between the genotypes (p > 0.05), although a lower IL-10 expression and release compared with PH CC was seen (p = 0.033 and p < 0.001). CONCLUSION: The rs6667202 SNP is functional in PH, as it decreases the expression and production of IL-10. In Perio4C, other factors may be masking its action by altering the IL-10's response.

Periosteum-derived cells as an alternative to bone marrow cells for bone tissue engineering around dental implants. A histomorphometric study in beagle dogs.

BACKGROUND: The aim of this study is to investigate the potential use of periosteum-derived cells (PCs) for tissue engineering in peri-implant defects. METHODS: Bone marrow cells (BMCs) and PCs were harvested from seven adult beagle dogs, cultured in vitro, and phenotypically characterized with regard to their osteogenic properties. The animals were then subjected to teeth extraction, and 3 months later, two implant sites were drilled, bone dehiscences created, and dental implants placed. Dehiscences were randomly assigned to one of two groups: PCs (PCs + carrier) and BMCs (BMCs + carrier). After 3 months, the animals were sacrificed and the implants with adjacent hard tissues were processed for undecalcified sections. Bone-to-implant contact, bone fill within the limits of implant threads, and new bone area in a zone lateral to the implant were histometrically obtained. RESULTS: In vitro, phenotypic characterization demonstrated that both cell populations presented osteogenic potential, as identified by the mineral nodule formation and the expression of bone markers. Histometrically, an intergroup analysis showed that both cell-treated defects had similar bone fill within the limits of implant threads and bone-to-implant contact (P >0.05), and although a trend toward higher new bone area values was found for the PC group, there was no significant difference between the experimental groups (P >0.05). CONCLUSIONS: Periosteal and bone marrow cells presented a similar potential for bone reconstruction. As such, periosteum may be considered as an alternative source of osteogenic cells in implant dentistry.