The effect of age on the gingival crevicular fluid composition during experimental gingivitis. A pilot study

Gingival crevicular fluid during experimental gingivitis: A review of immune and tissue regulation

BACKGROUND

This systematic review summarized the features of human experimental gingivitis (EG) in terms of immune responses and tissue remodeling in the gingival crevicular fluid (GCF).

METHODS

Systematic searches were conducted to screen the literature published from January 1960 to June 2024 from MEDLINE (PubMed), EMBASE, and Web of Science. The selected studies were prospective trials evaluating the immune responses and tissue remodeling mediators in GCF before and after EG via oral hygiene refrain. Evidence quality and risk of bias were assessed.

RESULTS

Thirty studies with 594 volunteers met the inclusion criteria, analyzing 74 clinical parameters and biomarkers in GCF samples. Consistent with EG induction, the EG sites showed an increase in plaque index (PI), gingival index (GI), and myeloperoxidase (MPO) (an indicator of neutrophil migration). In addition, the expression levels of interleukin (IL)-1α and IL-1β were increased, also consistent with the previous literature investigating active lesions of periodontal inflammation during gingivitis. However, the expression of macrophage inflammatory protein (MIP)-1 β, monocyte chemoattractant protein (MCP)-1, CCL2, and fractalkine/CX3CL1 decreased among EG in multiple studies demonstrating an EG effect on recruitment and cellular communication of mononuclear cells. In contrast, the levels of fibroblast growth factors (FGFs), vascular endothelial growth factor (VEGF), and anti-inflammatory cytokines showed insignificant changes during EG induction. Aging, stress level, and the diabetes status of the volunteer populations affected the outcomes.

CONCLUSIONS

The features of acute inflammatory lesions of EG with limited tissue destruction showcase that it is a valuable tool to investigate the initial immune responses on gingival tissue against bacterial challenges.

PLAIN LANGUAGE SUMMARY

This review examined how human experimental gingivitis (EG) affects immune responses and tissue changes in the fluid around the gums. Researchers analyzed studies published from 1960 to 2024, focusing on those that looked at immune responses and tissue changes in gum fluid before and after participants stopped brushing their teeth to induce EG. The review included 30 studies with 594 participants, exploring various health markers in gum fluid. When EG was induced, areas of the gums showed increased plaque and markers of inflammation, indicating an inflammatory response. Specifically, two inflammatory proteins (interleukin [IL]-1α and IL-1β) were found in greater expression, which aligns with what previous research has shown in gum disease. However, levels of certain proteins that help attract monocytes and macrophages decreased, suggesting changes in how these cells communicate during EG. Additionally, the levels of growth factors and anti-inflammatory substances did not change significantly. Factors such as age, stress, and diabetes also influenced the outcomes. These findings help us understand early immune responses in gum disease, which is crucial for developing prevention strategies and improving oral health overall.

Inflammation and tissue remodeling mediator expression during gingivitis: A comparison between experimental, naturally occurring gingivitis, and periodontal health

BACKGROUND

The aim of this study is to evaluate the immune regulation and tissue remodeling responses during experimental gingivitis (EG) and naturally occurring gingivitis (NG) to provide a comprehensive analysis of host responses. Gingival crevicular fluid (GCF) was obtained from 2 human studies conducted in university settings.

METHODS

The EG study enrolling 26 volunteers provided controls for the baseline (Day 0) from healthy disease-free participants, while Day 21 (the end of EG induction of the same group) was used to represent EG. Twenty-six NG participants age-matched with those of the EG group were recruited. GCF samples were analyzed for 39 mediators of inflammatory/immune responses and tissue remodeling using commercially available bead-based multiplex immunoassays. The differences in GI and mediator expression among groups were determined at a 95% confidence level (p ≤ 0.05) by a 2-way analysis of variance (ANOVA) with a post-hoc Tukey's test.

RESULTS

Our findings showed that EG had a greater gingival index than NG and was healthy (p < 0.01 of all comparisons). Furthermore, EG showed significantly higher levels of MPO (p < 0.001), CCL3 (p < 0.05), and IL-1B (p < 0.001) than NG. In contrast, NG had increased levels of MIF (p < 0.05), Fractalkine (p < 0.001), angiogenin (p < 0.05), C3a (p < 0.001), BMP-2 (p < 0.001), OPN (p < 0.05), RANKL (p < 0.001), and MMP-13 (p < 0.001) than EG.

CONCLUSIONS

Consistent with the findings from chronic (NG) versus acute (EG) inflammatory lesions, these data reveal that NG displays greater immune regulation, angiogenesis, and bone remodeling compared to EG.

Changes in Interleukin-1β, Tumor Necrosis Factor-α, and Interleukin-10 Cytokines in Older People with Periodontitis

Aging can change the ability to respond to various stimuli and physical conditions. A decreased immune response is a form of deterioration of function in older people, who then become more vulnerable when exposed to pathogens. Periodontitis is an inflammatory disease of the periodontal tissues that often occurs in older people. This study aimed to clinically analyze the periodontal status and cytokine levels of IL-1β, TNF-α, and IL-10 in older people and adults with periodontitis. This clinical study examined 20 persons in a group of older people and 20 persons in a group of adults. The clinical measurements of periodontal status included the Simplified Oral Hygiene Index (OHI-S), Plaque Index (PlI), and Papilla Bleeding Index (PBI). The cytokine levels in gingival crevicular fluid (GCF) were quantified by using ELISA kits. The OHI-S, PlI, and PBI were found to be higher in the older group. The mean values of cytokines were higher in the older group than in adults, although no statistically significant differences were found. A strong correlation was found between the clinical measurements and the cytokine levels in the GCF. There was an increasing tendency of pro-inflammatory and anti-inflammatory cytokines in the older group compared to the adult group.

Analysis of senescence in gingival tissues and gingival fibroblast cultures

Objective

To determine senescence‐associated changes in the gingival tissues of aged mice and gingival fibroblast cultures.

Materials and Methods

The production of senescence‐associated β‐galactosidase (SA‐β‐gal) and mRNA expression of p16, p21, interleukin (IL)‐1β, and tumor necrosis factor α (TNF‐α) were evaluated in gingival tissues, gingival fibroblasts of 10‐ and 20‐month‐old C57BL/6NCrl mice, and multiple‐passaged and hydrogen peroxide‐stimulated human gingival fibroblasts (HGFs). Changes in molecular expression in HGF cultures due to senescent cell elimination by the senolytic drug ABT‐263 (Navitoclax) were analyzed.

Results

Compared to 10‐week‐old mice, the 20‐month‐old mice had higher numbers of M1 macrophages. The proportion of cells expressing SA‐β‐gal were also higher in 20‐ month‐old mice than in 10‐week‐old‐mice. Gingival fibroblasts in 20‐month‐old mice expressed less collagen 1a1, collagen 4a1, and collagen 4a2 mRNA than those in 10‐week‐old mice. Compared to control cells, H2O2 treated HGF cells expressed higher levels of SA‐β‐gal and p16, p21, IL‐1β, and TNF‐α. Furthermore, ABT‐263 suppressed HGF cell expression of cytokines after senescence induction.

Conclusions

Senescence‐associated changes were observed in the gingival tissues of aged mice and HGF cultures. In addition, the potential of senolytic drugs to modify aging‐related changes in the gingiva was shown.

High Glucose Exacerbates TNF-α-Induced Proliferative Inhibition in Human Periodontal Ligament Stem Cells through Upregulation and Activation of TNF Receptor 1

Objective

This research is aimed at investigating how high glucose affects the proliferation and apoptosis in periodontal ligament stem cells (PDLSCs) in the presence of TNF-α.

Methods

PDLSCs obtained from periodontal healthy permanent teeth were treated under either high-glucose condition (30 mmol/L, G30 group) or normal glucose condition (5.6 mmol/L, G5.6 group) in the presence or absence of TNF-α (10 ng/ml) for 2 to 6 days. Cell proliferation and cell cycle were evaluated by CCK-8, EdU incorporation assay, and flow cytometry. Cell apoptosis was assessed by annexin V/PI staining. Protein expression was detected by western blotting. Cellular ROS expression was evaluated by CellROX labeling and flow cytometry. Specific antibodies targeting TNFR1 and TNFR2 were used to block TNF-α signaling. Vitamin C was also used to verify if the blockage of ROS can rescue PDLSCs in the presence of high glucose and TNF-α.

Results

CCK-8 assay showed that high glucose exacerbated TNF-α-induced cell viability inhibition (57.0%, 85.2%, and 100% for the G30+TNF-α group, G5.6+TNF-α group, and control group, respectively) on day 6. High glucose increased protein expression of TNFR1 compared with the control group on day 2 (1.24-fold) and day 6 (1.26-fold). Blocking TNFR1 totally reversed the proliferative inhibition in G30+TNF-α group. The addition of vitamin C or TNFR1 antibody totally reversed the elevation of intracellular ROS expression caused by high glucose and TNF-α. Vitamin C partially restored cell proliferation in the presence of high glucose and TNF-α.

Conclusion

High glucose exacerbates TNF-α-induced proliferative inhibition in human periodontal ligament stem cells through the upregulation and activation of TNF receptor 1. Inhibition of intracellular ROS expression by vitamin C partially rescues PDLSCs in terms of cell proliferation.

Resistance and resilience to experimental gingivitis: a systematic scoping review

BACKGROUND

This systematic scoping review aimed to identify changes in biomarkers of microbiological, immunological and biochemical origin during experimental gingivitis (EG) studies that might indicate resistance and resilience.

METHODS

The term 'experimental gingivitis' was run in PubMed from inception to April 11th, 2018. From the 411 studies retrieved, 22 studies were included for this review.

RESULTS

Studies reporting data on biomarker changes during and after full mouth EG trial were included. Two studies reported findings on changes in biomarkers of microbiological, 12 on immunological and eight on biochemical origin. Changes were reported in the induction phase, and occasionally in the resolution phase. The microbiological composition of both supragingival and subgingival dental plaque changed over the course of EG to a more pathogenic direction, but showed a shift back to a more normal composition. This indicates resilience of the oral microbiome. For immunological biomarkers, it was challenging to retrieve a robust pattern of changes across multiple studies. IL-1β and IL-6 in saliva and in gingival crevicular fluid increased during induction phase and returned in the resolution phase below baseline values. The biochemical parameters cystatin-SN, cystatin-S and lactoferrin in saliva were increased at the end of induction phase, however also here no clear pattern emerged based on all available studies.

CONCLUSIONS

More research is needed to investigate which microbiological, immunological, and biochemical biomarkers can be useful for future investigations into the resistance and resilience of the oral cavity to experimental gingivitis.

Experimental mucositis and experimental gingivitis in persons aged 70 or over. Clinical and biological responses

Objectives

To compare in persons aged 70 years or older the clinical and inflammatory changes occurring around implants and natural teeth during and after a phase of undisturbed plaque accumulation.

Material and methods

Twenty partially edentulous participants with titanium implants refrained from oral hygiene practices while being clinically monitored in weekly intervals for 21 days. Teeth and implants were then cleaned, oral hygiene resumed, and the participants were further monitored for 3 weeks. Twelve biomarkers were assessed in gingival and peri‐implant crevicular fluid (GCF, PCF).

Results

During 3 weeks of oral hygiene abstention, the gingival index (GI) continuously increased. On day 21, there were significantly more sites with GI >1 at implants than at teeth. After restarting oral hygiene, the GI decreased markedly in both groups. Throughout the experiment, the plaque index was significantly higher on teeth than on implants.

The different biomarkers reacted variably. IL‐1β increased significantly with plaque accumulation. IL‐1β, GM‐CSF, TNF‐α, and IFN‐γ were significantly higher in GCF compared to PCF at day 21. IL‐8 decreased significantly in GCF up to day 14. MIP‐1β decreased significantly in GCF, but not in PCF. At the 3‐week follow‐up, the levels of all biomarkers assessed in GCF and PCF had returned to baseline values.

Conclusions

In an elderly cohort, plaque accumulation induced an inflammatory reaction around both teeth and implants. Although there was less plaque accumulation on implants, the peri‐implant mucosa showed a stronger clinical response than gingiva.

Effects of curcumin on crevicular levels of IL-1β and CCL28 in experimental gingivitis

BACKGROUND

Curcumin has anti-inflammatory properties. The aim of this study was to compare interleukin-1β (IL-1β) and chemokine (C-C motif) ligand 28 (CCL28) levels following a topical application of curcumin (CRM), chlorhexidine (CHX) and chlorhexidine-metronidazole (CHX-MTZ) in an experimental gingivitis human model.

METHODS

Sixty systemically healthy selected subjects were randomly assigned to one of three topical antigingivitis gels. Each gel was applied twice daily for 10 minutes as the sole method of oral hygiene for 29 days on the test quadrant only. Modified gingival index (MGI), plaque index (PI), bleeding on probing (BOP) and probing depth (PD) were assessed at baseline, 29 days and 60 days. Estimation of IL-1β and CCL28 levels in gingival crevicular fluid was done at baseline and at 29 days.

RESULTS

The increase of IL-1β in the CRM (14.52 ± 16.6 pg/ml) and CHX-MTZ (31.63 ± 15.96) groups was significantly less than that of the CHX group (70.55 ± 38.81). Similar results were also observed for CCL28 (CRM: 8.12 ± 8.78 pg/ml; CHX-MTZ: 12.81 ± 18.68; CHX: 41.15 ± 22.82). All groups had a significant increase in MGI, PI and BOP at 29 days.

CONCLUSIONS

The anti-inflammatory potential of topical curcumin was similar to CHX-MTZ but superior to CHX in affecting IL-1β and CCL28 levels.

Comparison of the properties of human CD146+ and CD146- periodontal ligament cells in response to stimulation with tumour necrosis factor α

OBJECTIVES

Periodontal ligament stem cells (PDLSCs) can be used in periodontal regeneration. Tumour necrosis factor-alpha (TNF-α) participates in the regulation of cell proliferation, apoptosis, differentiation, and migration. However, whether TNF-α can affect the biological features of PDLSCs is still unclear. The objective of this study was to illustrate the biological effects (proliferation, apoptosis, osteogenesis and migration) of TNF-α on human CD146 positive periodontal ligament cells (CD146+PLDCs) and CD146 negative periodontal ligament cells (CD146-PDLCs).

METHODS

CD146±PDLCs were isolated from human PDLCs and analyzed using a fluorescence-activated cell sorter. The biological effects of TNF-α on CD146±PDLCs were evaluated by CCK-8 assay (proliferation), DAPI staining (apoptosis), alizarin red staining and alkaline phosphatase activities assay (osteogenesis), and wounding assay and transwell assay (migration).

RESULTS

CD146+PDLCs, which expressed MSC surface markers CD105, CD90, CD73, CD44, and Stro-1, showed higher proliferative and osteogenic potential than CD146-PDLCs. TNF-α at a dose of 2.5ng/ml was found to enhance both proliferation and osteogenesis in CD146+PDLCs. At 5ng/ml, TNF-α promoted proliferation, osteogenesis, and apoptosis in CD146+PDLCs and enhanced osteogenesis in CD146-PDLCs. At 10ng/ml, TNF-α only aggravated apoptosis in CD146+PDLCs. The migratory ability of both CD146+PDLCs and CD146-PDLCs was not altered by TNF-α.

CONCLUSIONS

CD146+PDLCs were subpopulation of MSC. It showed greater proliferative and osteogenic potential than CD146-PDLCs. At low concentration, TNF-α was beneficial to CD146+PDLCs on proliferation and osteogenesis, and at high concentration it was detrimental. CD146-PDLCs were found to be less sensitive to TNF-α.

The concentrations of IL-8 and IL-6 in gingival crevicular fluid during nickel-chromium alloy porcelain crown restoration

We explored gum irritation and cytotoxicity caused by nickel-chromium (Ni-Cr) alloy porcelain by interleukin-8 (IL-8), interleukin-6 (IL-6) and gingival crevicular fluid (GCF) volumes at different time points peri-crown restoration. This prospective study was conducted in 60 young adults. The total amount and concentrations of IL-8 and IL-6 per site, GCF volumes, and blood neutrophil counts were performed prior to and at 1 week, 3 months, and 6 months after Ni-Cr alloy-porcelain crown restoration. Thirty male and 30 female subjects, aged 20-35 years old were enrolled. The total amount and concentrations of IL-8 and IL-6 per site, GCF volumes increased after nickel-chromium (Ni-Cr) alloy-porcelain crown restoration, and reached its peak at the third month as the GCF volume increased by 52.20 %, the total amount and concentrations of IL-8 increased by 112.11 and 22.75 %; the total amount and concentrations of IL-6 increased by 77.66 and 17.17 % when compared to baseline. In particular, the increase of IL-8 concentration was found in female patients at 3 months after restoration; while the neutrophil count of the peripheral blood did not change significantly. The increase in the total amount and the concentrations of IL-8 and IL-6 and GCF volume may be related to the cytotoxicity induced by Ni-Cr alloy. The significant increase of IL-8 concentration in females indicates that more attention should be given to women during Ni-Cr alloy porcelain crown restoration.

The Dynamics of Oxidized LDL during Atherogenesis

Accumulating evidence indicates that oxidized low-density lipoprotein (OxLDL) is a useful marker for cardiovascular disease. The uptake of OxLDL by scavenger receptors leads to the accumulation of cholesterol within the foam cells of atherosclerotic lesions. OxLDL has many stimulatory effects on vascular cells, and the presence of OxLDL in circulating blood has been established. According to the classical hypothesis, OxLDL accumulates in the atherosclerotic lesions over a long duration, leading to advanced lesions. However, recent studies on time-course changes of OxLDL in vivo raised a possibility that OxLDL can be transferred between the lesions and the circulation. In this paper, the in vivo dynamics of OxLDL are discussed.