Chronic periodontitis is an inflammatory disease that affects the supporting tissues of the teeth... more Chronic periodontitis is an inflammatory disease that affects the supporting tissues of the teeth. It is initiated by specific bacteria within the plaque biofilm and progresses due to an abnormal inflammatory-immune response to those bacteria. Periodontitis is the major cause of tooth loss and is also significantly associated with an increased risk of stroke, type-2 diabetes and atheromatous heart disease.
Periodontitis is a ubiquitous and irreversible inflammatory condition and represents a significan... more Periodontitis is a ubiquitous and irreversible inflammatory condition and represents a significant public health burden. Severe periodontitis affects over 11% of adults, is a major case of tooth loss impacting negatively upon speech, nutrition, quality of life and self-esteem and has systemic inflammatory consequences. Periodontitis is treatable and treatment leads to reduced rates of tooth loss and improved quality of life. However, successful treatment necessitates behaviour change in patients to address lifestyle risk factors (e.g. smoking) and, most importantly, to attain and sustain high standards of daily plaque removal, life-long. Whilst mechanical plaque removal remains the bedrock of successful periodontal disease management, in high risk patients it appears that the critical threshold for plaque accumulation to trigger periodontitis is low, and such patients may benefit from adjunctive agents for primary prevention of periodontitis.AimThe aims of this working group were to...
To investigate microbiological biofilm contamination of retrieved bone-anchored hearing aids. Nin... more To investigate microbiological biofilm contamination of retrieved bone-anchored hearing aids. Nine failed, retrieved bone-anchored hearing aids and 16 internal screws were examined by scanning electron microscopy. A fixture from a failing implant, which had been removed and disassembled under aseptic conditions, was cultured. Finally, an internal screw from a new, unimplanted fixture was examined by scanning electron microscopy. Debris was seen on the fixture and abutment of all bone-anchored hearing aids, and on the heads of the 16 internal screws. On eight screws, biofilm extended down the shaft to the threads, where it was several micrometres thick. Culture of a failing fixture yielded staphylococcus. The new, unimplanted fixture internal screw showed evidence of scratching and metallic debris on the threads, which may interfere with close fitting of the screw and subsequently facilitate microleakage. There may be a link between internal microbial contamination and failure of bon...
Objectives: Investigations using high resolution synchrotron x-ray fluorescence mapping have demo... more Objectives: Investigations using high resolution synchrotron x-ray fluorescence mapping have demonstrated free titanium (Ti) distributions within soft tissues adjacent to craniofacial and orthopaedic Ti-implants. Characterization of the soft tissues using XANES revealed multiple Ti species including anatase and rutile. This study aimed to: 1) determine the pro-inflammatory potential of both species by studying neutrophil oxidative reactivity; 2) demonstrate intracellularisation of Ti by neutrophils using synchrotron x-ray techniques. Methods: Human peripheral blood neutrophils from healthy volunteers (n=20) were purified by density centrifugation, challenged with anatase and rutile powders dispersed in PBS at 2000, 200 and 20ppm. Neutrophils were challenged with opsonised S.aureus (MOI: 300:1) and F.nucleatum (MOI: 100-1) as positive controls. Total and extracellular reactive oxygen species (ROS) were measured by luminol/isoluminol chemiluminescence. Data were analysed by Wilcoxon t...
Objectives: Advanced biophysical imaging techniques have demonstrated accumulation and speciation... more Objectives: Advanced biophysical imaging techniques have demonstrated accumulation and speciation of titanium (Ti) ions and particles in soft tissues adjacent to skin/mucosa penetrating implants. Neutrophils are co-localised with Ti-debris and are central in the pathogenesis of peri-implantitis. We aimed to determine the potential of relevant Ti-debris, to modify the peri-implant inflammatory response through interactions with human neutrophils. Methods: Neutrophils isolated from heparinised blood (n=10-20/experiment) were challenged with Ti (as anatase/rutile/metallic or peroxide-complex) in different particle sizes (30nm to 20μm) at concentrations in PBS from 0 to 2000ppm. Opsonised S.aureus (MOI:300-bacteria/neutrophil) and F.nucleatum (MOI:100-1) acted as positive controls. Total/extracellular Reactive Oxygen Species (ROS) release was measured by luminol/isoluminol chemiluminescence. Ti-debris' capacity to perturb neutrophil ROS release to peri-implant pathogens was assessed...
Objective: To investigate differences in chemotactic accuracy of peripheral blood neutrophils (PB... more Objective: To investigate differences in chemotactic accuracy of peripheral blood neutrophils (PBNs) in periodontitis patients verses unaffected controls and whether periodontal treatment impacts upon PBN chemotactic behaviour. Background: Chronic periodontitis is highly prevalent and associated with neutrophil-mediated host tissue damage due to neutrophil hyper-activity/reactivity in respect of reactive oxygen species and proteolytic enzyme release. Such collateral tissue damage may be exacerbated by reduced neutrophil tissue transit times and/or delayed apoptosis/impaired efferocytosis. To date, studies have focussed upon neutrophil chemokinesis in periodontitis patients rather than true chemotaxis. Here we employed a novel bridge chamber, the “Insall Chamber”, to investigate directional chemotaxis of PBNs in response to different stimuli in periodontitis patients and matched controls, prior to and following non-surgical treatment. Method: Neutrophils were isolated from periodonti...
Gingivitis is a pre-requisite for periodontitis, but does not automatically lead to periodontitis... more Gingivitis is a pre-requisite for periodontitis, but does not automatically lead to periodontitis in all patients. Nevertheless, managing gingival inflammation is a primary preventive strategy for periodontitis. Gingival crevicular fluid (GCF) provides a representative biological fingerprint of both host and microbial events and their interactions, which can be used to inform new learning’s in disease pathogenesis and in the development of diagnostic and prognostic markers. Objective: To quantify changes in the GCF proteome collected from strictly phenotyped healthy volunteers and gingivitis sufferers using a non-presumptive approach. Methods: GCF was collected from two groups: periodontally healthy volunteers and volunteers with gingivitis onto PeriopaperTM strips from six sites per volunteer. Samples were immediately frozen (-80oC). Prior to assay, GCF samples were defrosted, vortexed and the supernatant was retained. All samples in each group were pooled and digested with Lys-C a...
Biomarkers that discriminate gingivitis from periodontitis may facilitate early diagnosis of dest... more Biomarkers that discriminate gingivitis from periodontitis may facilitate early diagnosis of destructive periodontal diseases and serve as objective outcome measures of therapy. Quantitative mass spectrometry (Q-MS) has the potential to identify such biomarkers. Objective: To identify putative periodontal disease biomarkers via quantitative analysis of relative abundances of peptides within gingivial crevicular fluid (GCF) from individual teeth in dogs that progressed from mild gingivitis to periodontitis, using Q-MS and isobaric molecular tags. Methods: As part of an ethically approved trial, GCF was collected from 13 Miniature Schnauzer dogs under general anaesthesia. Samples were collected from 15 teeth at three time points (45 samples in total) as they progressed naturally from mild gingivitis to severe gingivitis and finally to mild periodontitis (based on Wiggs & Lobprise scoring system). GCF was collected on paper points, digested and labelled with iTRAQ 4-plex (ABSciex) tags...
Gingival crevicular fluid (GCF) is a complex biological fluid and has been used for disease bioma... more Gingival crevicular fluid (GCF) is a complex biological fluid and has been used for disease biomarker analysis for several years. This is the first study to compare health with mild and severe periodontitis pre- and post-treatment using quantitative mass spectrometry (Q-MS) to identify differences in abundance of GCF proteins between patient groups. Objective: To quantify differences in the GCF proteome between healthy dentate volunteers, and volunteers with periodontitis using Q-MS, to elucidate relative abundances of proteins in GCF. Methods: GCF was collected from three groups: periodontally healthy volunteers (n=10), and those with mild (n=10) and severe (n=10) periodontitis. GCF was collected on PeriopapersTM from six sites per volunteer and immediately frozen (-80oC). Samples were taken pre- and post-periodontal therapy, providing a total of five groups. Prior to assay, GCF samples were defrosted, vortexed and the supernatant was retained. Samples in each group were pooled and...
Objective: Periodontitis is one of the most common infectious-inflammatory diseases of humans wit... more Objective: Periodontitis is one of the most common infectious-inflammatory diseases of humans with prevalence for severe disease of 10-15% of adults worldwide (WHO). Periodontitis is caused by dysregulated inflammatory-immune responses to bacteria that adhere to and colonise the teeth. If left untreated chronic inflammation results, eventually leading to tooth loss. Neutrophils, the most prevalent innate immune cell present in blood, are the first line of defence during microbial infections. The recruitment of neutrophils to and from the site of infection is an essential step in innate and acquired immunity. Previous studies claim to have demonstrated defective chemotaxis in periodontitis sufferers using bridge chambers; however such chambers measure chemokinesis rather than chemotaxis, where accuracy and velocity of directional movement should be measured. We therefore analysed directional chemotaxis in response of peripheral blood neutrophils to different stimuli in periodontitis ...
Chronic periodontal diseases are characterised by a dysregulated and exaggerated inflammatory/imm... more Chronic periodontal diseases are characterised by a dysregulated and exaggerated inflammatory/immune response to plaque bacteria. We have demonstrated previously that oral keratinocytes up-regulate key molecular markers of inflammation, including NF-κB and cytokine signalling, when exposed to the periodontal bacteria Porphyromonas gingivalis and Fusobacterium nucleatum in vitro. The purpose of the current study was to investigate whether α-lipoic acid was able to abrogate bacterially-induced pro-inflammatory changes in the H400 oral epithelial cell line. Initial studies indicated that α-lipoic acid supplementation (1-4 mM) significantly reduced cell attachment; lower concentrations (<0.5 mM) enabled >85% cell adhesion at 24 h. While a pro-inflammatory response, demonstrable by NF-κB translocation, gene expression and protein production was evident in H400 cells following exposure to P. gingivalis and F. nucleatum, pre-incubation of cells with 0.5 mM α-lipoic acid modulated thi...
Epithelial cell responses to Titanate nano-particles depends on agglomeration Objectives: Detecta... more Epithelial cell responses to Titanate nano-particles depends on agglomeration Objectives: Detectable levels of Titanium (Ti) in sera of patients with implants and the presence of Ti-oxide species in peri-implant tissues confirm Ti-ion release from such devices. Released Ti4+, has been demonstrated to bind to protein components of the immediate environment or rapidly oxidize to form insoluble nano-scale particulates. In-vitro modeling of cell responses to nano-particles (NPs) is often compromised by failures by investigators to adequately avoid NP agglomerations. The objectives were to (i) prevent NP agglomerations in relevant media and (ii) modification of cell responses following exposure to agglomerated and dispersed NPs. Methods: Two TiO2 NP dispersions were prepared; (i) TiO2 was added directly to Dulbecco's Modified Eagle Medium (DMEM)(Gibco, UK), (OM) (ii) The Branson 450 sonicator (Branson Ultrasonics, USA) was used to disperse TiO2 NP's in distilled water. The disper...
Objectives: There is an increasing body of evidence demonstrating that Titanium (Ti) in various f... more Objectives: There is an increasing body of evidence demonstrating that Titanium (Ti) in various forms is present in tissues surrounding implanted biomedical devices. These Ti species may be present as micron sized metallic fragments or as nanoscale oxide particles (NPs). Low levels of Ti-oxide in tissues can be explained through biocorrosion or mechanically assisted crevice corrosion mechanisms. Cellular interactions with nanoscale Ti-oxides have been demonstrated to be potentially pro-inflammatory, however the effects of Ti derivatives on oral epithelial cells in the immediate environment of dental implants, are poorly characterised. The aims were to determine: whether oral keratinocytes show the capacity to internalise nanoscale Ti and agglomerations thereof; to determine any patterns of uptake and effects on cellular viability and to investigate potential differences between immortalised and primary cells. Methods: Intracellularisation of Ti NPs was characterised using transmissi...
Objectives: Recent investigations using synchrotron x-rays have demonstrated free Titanium (Ti) i... more Objectives: Recent investigations using synchrotron x-rays have demonstrated free Titanium (Ti) in various forms in tissues adjacent to dental, craniofacial and orthopaedic implants. Elevated serum-Ti levels in patients with implants not subjected to wear processes have also been demonstrated suggesting a slow degradation of Ti surfaces. Epithelial responses to implant placement is key to success, however minimal research has investigated the effects of free-Ti on epithelial cells. We aim to (i) identify the variables influencing the release of metal ions/particles from Ti surfaces and (ii) investigate the interaction of free-Ti in sizes and species characterised in tissue, with oral epithelial cells Methods: Ion release from Grade-IV-Ti was performed in immersion studies with Ti4+ release determined using ICP-MS (sensitive to ppb). Peri-implant fluids can contain F-, endotoxin and peroxide species, which have been demonstrated to modify the passivity of Ti surface oxide films and w...
Periodontitis is a chronic inflammatory disease that is characterized by loss of the periodontal ... more Periodontitis is a chronic inflammatory disease that is characterized by loss of the periodontal ligament and alveolar bone, and is a major cause of tooth loss. Results from clinical and epidemiologic studies have suggested that periodontitis and tooth loss are more prevalent in individuals with rheumatoid arthritis (RA). However, the strength and temporality of the association are uncertain. Several biologically plausible causal and noncausal mechanisms might account for this association between periodontitis and RA. There is evidence to suggest that periodontitis could indeed be a causal factor in the initiation and maintenance of the autoimmune inflammatory response that occurs in RA. If proven, chronic periodontitis might represent an important modifiable risk factor for RA. In addition, patients with RA might show an increased risk of developing periodontitis and tooth loss through various mechanisms. Moreover, exposure to common genetic, environmental or behavioral factors mig...
Studies suggest that periodontitis may be a risk factor for rheumatoid arthritis (RA). The purpos... more Studies suggest that periodontitis may be a risk factor for rheumatoid arthritis (RA). The purpose of this study was to determine whether periodontitis is associated with autoantibodies characteristic of RA. Serum samples were tested for anti-cyclic citrullinated peptide (CCP), anti-mutated citrullinated vimentin (MCV), anti-citrullinated α-enolase peptide-1 (CEP-1), anti-citrullinated vimentin (cit-vim), anti-citrullinated fibrinogen (cit-fib) and their uncitrullinated forms anti-CParg (negative control for anti-CCP), anti-arginine-containing α-enolase peptide-1 (REP-1), anti-vimentin and anti-fibrinogen antibodies in patients with and without periodontitis, none of whom had RA. Periodontitis, compared with non-periodontitis, was associated with a normal frequency of anti-CCP and anti-MCV (∼1%) but a higher frequency of positive anti-CEP-1 (12% vs 3%; p=0.02) and its uncitrullinated form anti-REP-1 (16% vs 2%; p<0.001). Positive antibodies against uncitrullinated fibrinogen and ...
Neutrophil extracellular traps (NETs) are a recently discovered addition to the defensive armamen... more Neutrophil extracellular traps (NETs) are a recently discovered addition to the defensive armamentarium of neutrophils, assisting in the immune response against rapidly dividing bacteria. Although older adults are more susceptible to such infections, no study has examined whether aging in humans influences NET formation. We report that TNF-a-primed neutrophils generate significantly more NETs than unprimed neutrophils and that lipopolysaccharide (LPS)and interleukin-8 (IL-8)-induced NET formation exhibits a significant age-related decline. NET formation requires generation of reactive oxygen species (ROS), and this was also reduced in neutrophils from older donors identifying a mechanism for reduced NET formation. Expression of IL-8 receptors (CXCR1 and CXCR2) and the LPS receptor TLR4 was similar on neutrophils from young and old subjects, and neutrophils challenged with phorbol-12-myristate-13-acetate (PMA) showed no age-associated differences in ROS or NET production. Taken together, these data suggest a defect in proximal signalling underlies the age-related decline in NET and ROS generation. TNF-a priming involves signalling through p38 MAP kinase, but activation kinetics were comparable in neutrophils from young and old donors. In a clinical setting, we assessed the capacity of neutrophils from young and older patients with chronic periodontitis to generate NETs in response to PMA and hypochlorous acid (HOCL). Neutrophil extracellular trap generation to HOCL, but not PMA, was lower in older periodontitis patients but not in comparison with age-matched controls. Impaired NET formation is thus a novel defect of innate immunity in older adults but does not appear to contribute to the increased incidence of periodontitis in older adults.
Chronic periodontitis is an inflammatory disease that affects the supporting tissues of the teeth... more Chronic periodontitis is an inflammatory disease that affects the supporting tissues of the teeth. It is initiated by specific bacteria within the plaque biofilm and progresses due to an abnormal inflammatory-immune response to those bacteria. Periodontitis is the major cause of tooth loss and is also significantly associated with an increased risk of stroke, type-2 diabetes and atheromatous heart disease.
Periodontitis is a ubiquitous and irreversible inflammatory condition and represents a significan... more Periodontitis is a ubiquitous and irreversible inflammatory condition and represents a significant public health burden. Severe periodontitis affects over 11% of adults, is a major case of tooth loss impacting negatively upon speech, nutrition, quality of life and self-esteem and has systemic inflammatory consequences. Periodontitis is treatable and treatment leads to reduced rates of tooth loss and improved quality of life. However, successful treatment necessitates behaviour change in patients to address lifestyle risk factors (e.g. smoking) and, most importantly, to attain and sustain high standards of daily plaque removal, life-long. Whilst mechanical plaque removal remains the bedrock of successful periodontal disease management, in high risk patients it appears that the critical threshold for plaque accumulation to trigger periodontitis is low, and such patients may benefit from adjunctive agents for primary prevention of periodontitis.AimThe aims of this working group were to...
To investigate microbiological biofilm contamination of retrieved bone-anchored hearing aids. Nin... more To investigate microbiological biofilm contamination of retrieved bone-anchored hearing aids. Nine failed, retrieved bone-anchored hearing aids and 16 internal screws were examined by scanning electron microscopy. A fixture from a failing implant, which had been removed and disassembled under aseptic conditions, was cultured. Finally, an internal screw from a new, unimplanted fixture was examined by scanning electron microscopy. Debris was seen on the fixture and abutment of all bone-anchored hearing aids, and on the heads of the 16 internal screws. On eight screws, biofilm extended down the shaft to the threads, where it was several micrometres thick. Culture of a failing fixture yielded staphylococcus. The new, unimplanted fixture internal screw showed evidence of scratching and metallic debris on the threads, which may interfere with close fitting of the screw and subsequently facilitate microleakage. There may be a link between internal microbial contamination and failure of bon...
Objectives: Investigations using high resolution synchrotron x-ray fluorescence mapping have demo... more Objectives: Investigations using high resolution synchrotron x-ray fluorescence mapping have demonstrated free titanium (Ti) distributions within soft tissues adjacent to craniofacial and orthopaedic Ti-implants. Characterization of the soft tissues using XANES revealed multiple Ti species including anatase and rutile. This study aimed to: 1) determine the pro-inflammatory potential of both species by studying neutrophil oxidative reactivity; 2) demonstrate intracellularisation of Ti by neutrophils using synchrotron x-ray techniques. Methods: Human peripheral blood neutrophils from healthy volunteers (n=20) were purified by density centrifugation, challenged with anatase and rutile powders dispersed in PBS at 2000, 200 and 20ppm. Neutrophils were challenged with opsonised S.aureus (MOI: 300:1) and F.nucleatum (MOI: 100-1) as positive controls. Total and extracellular reactive oxygen species (ROS) were measured by luminol/isoluminol chemiluminescence. Data were analysed by Wilcoxon t...
Objectives: Advanced biophysical imaging techniques have demonstrated accumulation and speciation... more Objectives: Advanced biophysical imaging techniques have demonstrated accumulation and speciation of titanium (Ti) ions and particles in soft tissues adjacent to skin/mucosa penetrating implants. Neutrophils are co-localised with Ti-debris and are central in the pathogenesis of peri-implantitis. We aimed to determine the potential of relevant Ti-debris, to modify the peri-implant inflammatory response through interactions with human neutrophils. Methods: Neutrophils isolated from heparinised blood (n=10-20/experiment) were challenged with Ti (as anatase/rutile/metallic or peroxide-complex) in different particle sizes (30nm to 20μm) at concentrations in PBS from 0 to 2000ppm. Opsonised S.aureus (MOI:300-bacteria/neutrophil) and F.nucleatum (MOI:100-1) acted as positive controls. Total/extracellular Reactive Oxygen Species (ROS) release was measured by luminol/isoluminol chemiluminescence. Ti-debris' capacity to perturb neutrophil ROS release to peri-implant pathogens was assessed...
Objective: To investigate differences in chemotactic accuracy of peripheral blood neutrophils (PB... more Objective: To investigate differences in chemotactic accuracy of peripheral blood neutrophils (PBNs) in periodontitis patients verses unaffected controls and whether periodontal treatment impacts upon PBN chemotactic behaviour. Background: Chronic periodontitis is highly prevalent and associated with neutrophil-mediated host tissue damage due to neutrophil hyper-activity/reactivity in respect of reactive oxygen species and proteolytic enzyme release. Such collateral tissue damage may be exacerbated by reduced neutrophil tissue transit times and/or delayed apoptosis/impaired efferocytosis. To date, studies have focussed upon neutrophil chemokinesis in periodontitis patients rather than true chemotaxis. Here we employed a novel bridge chamber, the “Insall Chamber”, to investigate directional chemotaxis of PBNs in response to different stimuli in periodontitis patients and matched controls, prior to and following non-surgical treatment. Method: Neutrophils were isolated from periodonti...
Gingivitis is a pre-requisite for periodontitis, but does not automatically lead to periodontitis... more Gingivitis is a pre-requisite for periodontitis, but does not automatically lead to periodontitis in all patients. Nevertheless, managing gingival inflammation is a primary preventive strategy for periodontitis. Gingival crevicular fluid (GCF) provides a representative biological fingerprint of both host and microbial events and their interactions, which can be used to inform new learning’s in disease pathogenesis and in the development of diagnostic and prognostic markers. Objective: To quantify changes in the GCF proteome collected from strictly phenotyped healthy volunteers and gingivitis sufferers using a non-presumptive approach. Methods: GCF was collected from two groups: periodontally healthy volunteers and volunteers with gingivitis onto PeriopaperTM strips from six sites per volunteer. Samples were immediately frozen (-80oC). Prior to assay, GCF samples were defrosted, vortexed and the supernatant was retained. All samples in each group were pooled and digested with Lys-C a...
Biomarkers that discriminate gingivitis from periodontitis may facilitate early diagnosis of dest... more Biomarkers that discriminate gingivitis from periodontitis may facilitate early diagnosis of destructive periodontal diseases and serve as objective outcome measures of therapy. Quantitative mass spectrometry (Q-MS) has the potential to identify such biomarkers. Objective: To identify putative periodontal disease biomarkers via quantitative analysis of relative abundances of peptides within gingivial crevicular fluid (GCF) from individual teeth in dogs that progressed from mild gingivitis to periodontitis, using Q-MS and isobaric molecular tags. Methods: As part of an ethically approved trial, GCF was collected from 13 Miniature Schnauzer dogs under general anaesthesia. Samples were collected from 15 teeth at three time points (45 samples in total) as they progressed naturally from mild gingivitis to severe gingivitis and finally to mild periodontitis (based on Wiggs & Lobprise scoring system). GCF was collected on paper points, digested and labelled with iTRAQ 4-plex (ABSciex) tags...
Gingival crevicular fluid (GCF) is a complex biological fluid and has been used for disease bioma... more Gingival crevicular fluid (GCF) is a complex biological fluid and has been used for disease biomarker analysis for several years. This is the first study to compare health with mild and severe periodontitis pre- and post-treatment using quantitative mass spectrometry (Q-MS) to identify differences in abundance of GCF proteins between patient groups. Objective: To quantify differences in the GCF proteome between healthy dentate volunteers, and volunteers with periodontitis using Q-MS, to elucidate relative abundances of proteins in GCF. Methods: GCF was collected from three groups: periodontally healthy volunteers (n=10), and those with mild (n=10) and severe (n=10) periodontitis. GCF was collected on PeriopapersTM from six sites per volunteer and immediately frozen (-80oC). Samples were taken pre- and post-periodontal therapy, providing a total of five groups. Prior to assay, GCF samples were defrosted, vortexed and the supernatant was retained. Samples in each group were pooled and...
Objective: Periodontitis is one of the most common infectious-inflammatory diseases of humans wit... more Objective: Periodontitis is one of the most common infectious-inflammatory diseases of humans with prevalence for severe disease of 10-15% of adults worldwide (WHO). Periodontitis is caused by dysregulated inflammatory-immune responses to bacteria that adhere to and colonise the teeth. If left untreated chronic inflammation results, eventually leading to tooth loss. Neutrophils, the most prevalent innate immune cell present in blood, are the first line of defence during microbial infections. The recruitment of neutrophils to and from the site of infection is an essential step in innate and acquired immunity. Previous studies claim to have demonstrated defective chemotaxis in periodontitis sufferers using bridge chambers; however such chambers measure chemokinesis rather than chemotaxis, where accuracy and velocity of directional movement should be measured. We therefore analysed directional chemotaxis in response of peripheral blood neutrophils to different stimuli in periodontitis ...
Chronic periodontal diseases are characterised by a dysregulated and exaggerated inflammatory/imm... more Chronic periodontal diseases are characterised by a dysregulated and exaggerated inflammatory/immune response to plaque bacteria. We have demonstrated previously that oral keratinocytes up-regulate key molecular markers of inflammation, including NF-κB and cytokine signalling, when exposed to the periodontal bacteria Porphyromonas gingivalis and Fusobacterium nucleatum in vitro. The purpose of the current study was to investigate whether α-lipoic acid was able to abrogate bacterially-induced pro-inflammatory changes in the H400 oral epithelial cell line. Initial studies indicated that α-lipoic acid supplementation (1-4 mM) significantly reduced cell attachment; lower concentrations (<0.5 mM) enabled >85% cell adhesion at 24 h. While a pro-inflammatory response, demonstrable by NF-κB translocation, gene expression and protein production was evident in H400 cells following exposure to P. gingivalis and F. nucleatum, pre-incubation of cells with 0.5 mM α-lipoic acid modulated thi...
Epithelial cell responses to Titanate nano-particles depends on agglomeration Objectives: Detecta... more Epithelial cell responses to Titanate nano-particles depends on agglomeration Objectives: Detectable levels of Titanium (Ti) in sera of patients with implants and the presence of Ti-oxide species in peri-implant tissues confirm Ti-ion release from such devices. Released Ti4+, has been demonstrated to bind to protein components of the immediate environment or rapidly oxidize to form insoluble nano-scale particulates. In-vitro modeling of cell responses to nano-particles (NPs) is often compromised by failures by investigators to adequately avoid NP agglomerations. The objectives were to (i) prevent NP agglomerations in relevant media and (ii) modification of cell responses following exposure to agglomerated and dispersed NPs. Methods: Two TiO2 NP dispersions were prepared; (i) TiO2 was added directly to Dulbecco's Modified Eagle Medium (DMEM)(Gibco, UK), (OM) (ii) The Branson 450 sonicator (Branson Ultrasonics, USA) was used to disperse TiO2 NP's in distilled water. The disper...
Objectives: There is an increasing body of evidence demonstrating that Titanium (Ti) in various f... more Objectives: There is an increasing body of evidence demonstrating that Titanium (Ti) in various forms is present in tissues surrounding implanted biomedical devices. These Ti species may be present as micron sized metallic fragments or as nanoscale oxide particles (NPs). Low levels of Ti-oxide in tissues can be explained through biocorrosion or mechanically assisted crevice corrosion mechanisms. Cellular interactions with nanoscale Ti-oxides have been demonstrated to be potentially pro-inflammatory, however the effects of Ti derivatives on oral epithelial cells in the immediate environment of dental implants, are poorly characterised. The aims were to determine: whether oral keratinocytes show the capacity to internalise nanoscale Ti and agglomerations thereof; to determine any patterns of uptake and effects on cellular viability and to investigate potential differences between immortalised and primary cells. Methods: Intracellularisation of Ti NPs was characterised using transmissi...
Objectives: Recent investigations using synchrotron x-rays have demonstrated free Titanium (Ti) i... more Objectives: Recent investigations using synchrotron x-rays have demonstrated free Titanium (Ti) in various forms in tissues adjacent to dental, craniofacial and orthopaedic implants. Elevated serum-Ti levels in patients with implants not subjected to wear processes have also been demonstrated suggesting a slow degradation of Ti surfaces. Epithelial responses to implant placement is key to success, however minimal research has investigated the effects of free-Ti on epithelial cells. We aim to (i) identify the variables influencing the release of metal ions/particles from Ti surfaces and (ii) investigate the interaction of free-Ti in sizes and species characterised in tissue, with oral epithelial cells Methods: Ion release from Grade-IV-Ti was performed in immersion studies with Ti4+ release determined using ICP-MS (sensitive to ppb). Peri-implant fluids can contain F-, endotoxin and peroxide species, which have been demonstrated to modify the passivity of Ti surface oxide films and w...
Periodontitis is a chronic inflammatory disease that is characterized by loss of the periodontal ... more Periodontitis is a chronic inflammatory disease that is characterized by loss of the periodontal ligament and alveolar bone, and is a major cause of tooth loss. Results from clinical and epidemiologic studies have suggested that periodontitis and tooth loss are more prevalent in individuals with rheumatoid arthritis (RA). However, the strength and temporality of the association are uncertain. Several biologically plausible causal and noncausal mechanisms might account for this association between periodontitis and RA. There is evidence to suggest that periodontitis could indeed be a causal factor in the initiation and maintenance of the autoimmune inflammatory response that occurs in RA. If proven, chronic periodontitis might represent an important modifiable risk factor for RA. In addition, patients with RA might show an increased risk of developing periodontitis and tooth loss through various mechanisms. Moreover, exposure to common genetic, environmental or behavioral factors mig...
Studies suggest that periodontitis may be a risk factor for rheumatoid arthritis (RA). The purpos... more Studies suggest that periodontitis may be a risk factor for rheumatoid arthritis (RA). The purpose of this study was to determine whether periodontitis is associated with autoantibodies characteristic of RA. Serum samples were tested for anti-cyclic citrullinated peptide (CCP), anti-mutated citrullinated vimentin (MCV), anti-citrullinated α-enolase peptide-1 (CEP-1), anti-citrullinated vimentin (cit-vim), anti-citrullinated fibrinogen (cit-fib) and their uncitrullinated forms anti-CParg (negative control for anti-CCP), anti-arginine-containing α-enolase peptide-1 (REP-1), anti-vimentin and anti-fibrinogen antibodies in patients with and without periodontitis, none of whom had RA. Periodontitis, compared with non-periodontitis, was associated with a normal frequency of anti-CCP and anti-MCV (∼1%) but a higher frequency of positive anti-CEP-1 (12% vs 3%; p=0.02) and its uncitrullinated form anti-REP-1 (16% vs 2%; p<0.001). Positive antibodies against uncitrullinated fibrinogen and ...
Neutrophil extracellular traps (NETs) are a recently discovered addition to the defensive armamen... more Neutrophil extracellular traps (NETs) are a recently discovered addition to the defensive armamentarium of neutrophils, assisting in the immune response against rapidly dividing bacteria. Although older adults are more susceptible to such infections, no study has examined whether aging in humans influences NET formation. We report that TNF-a-primed neutrophils generate significantly more NETs than unprimed neutrophils and that lipopolysaccharide (LPS)and interleukin-8 (IL-8)-induced NET formation exhibits a significant age-related decline. NET formation requires generation of reactive oxygen species (ROS), and this was also reduced in neutrophils from older donors identifying a mechanism for reduced NET formation. Expression of IL-8 receptors (CXCR1 and CXCR2) and the LPS receptor TLR4 was similar on neutrophils from young and old subjects, and neutrophils challenged with phorbol-12-myristate-13-acetate (PMA) showed no age-associated differences in ROS or NET production. Taken together, these data suggest a defect in proximal signalling underlies the age-related decline in NET and ROS generation. TNF-a priming involves signalling through p38 MAP kinase, but activation kinetics were comparable in neutrophils from young and old donors. In a clinical setting, we assessed the capacity of neutrophils from young and older patients with chronic periodontitis to generate NETs in response to PMA and hypochlorous acid (HOCL). Neutrophil extracellular trap generation to HOCL, but not PMA, was lower in older periodontitis patients but not in comparison with age-matched controls. Impaired NET formation is thus a novel defect of innate immunity in older adults but does not appear to contribute to the increased incidence of periodontitis in older adults.
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