Saliva in perimenopausal and early postmenopausal women. A 2-year follow-up study

Characterising salivary peptidome across diurnal dynamics and variations induced by sampling procedures

OBJECTIVES

This study aimed to characterise diurnal dynamics of salivary peptidome and variations induced by sampling procedures.

MATERIALS AND METHODS

A supervised short-term longitudinal study was conducted amongst ten healthy participants. Saliva samples were collected by different procedures (stimulated/unstimulated conditions, forepart/midstream segments) on three consecutive days. The peptidome compositions of saliva samples were analysed using matrix-assisted laser desorption/ionisation-time of flight-mass spectrometry (MALDI-TOF MS).

RESULTS

The salivary peptidome exhibited a stable trend generally, even though some diurnal dynamics happened in aspects of both overall structure and certain single peptides. The results indicated saliva samples collected under unstimulated and stimulated conditions have significantly different structures of peptidome, whilst the peptidome profile of stimulated saliva was more abundant than that of unstimulated saliva. It was also indicated that the midstream segment effect might exist in the segmented process of saliva sampling.

CONCLUSIONS

In summary, salivary peptidome was able to maintain stability though some dynamic changes might happen within a short-term period. Stimulated and unstimulated saliva samples had significantly different peptidome profiles, whilst the stimulated whole saliva was a larger pool of low molecular weight peptides.

CLINICAL RELEVANCE

The stability of the salivary peptidome highlights the reliability of salivary peptidome as a source of diagnostic biomarker. We recommend keeping one collection condition (stimulated/unstimulated) consistently within one study on salivary peptidome. Stimulated whole saliva would be preferred if more abundant peptidome profile is needed.

Comparative analysis of the effects of collection methods on salivary steroids

BACKGROUND

Steroid hormone test for saliva was a promising area of research, however the impact of different collection methods on salivary steroids was underexplored so far. This study was designed to compare the effects of different collection methods (unstimulated or stimulated by chewing paraffin, forepart or midstream) on salivary flow rate, concentrations and secretion rates of steroids in saliva.

METHODS

Whole-saliva samples were collected from 10 systemically and orally healthy participants, whose forepart and midstream segments of saliva were collected under unstimulated and stimulated conditions, with the salivary flow rate of each sample recorded. The concentrations and secretion rates of salivary steroids including testosterone, dehydroepiandrosterone (DHEA) and progesterone were measured by ELISA, with the multiple of change calculated.

RESULTS

The results indicated mechanical stimulation used in collection of saliva samples could affect concentrations and secretion rates of steroids, whereas forepart and midstream segments had little differences in levels of salivary steroids, which effects could be partly influenced by individual specificity. The asynchronism in change of secretion rate of steroids with that of salivary flow rate might play an important role during this course.

CONCLUSION

Based on these findings, we suggested to use the same collection method throughout one analytical study on salivary steroids or in longitudinal observations to ensure the comparability of the saliva samples collected.

Female sex as an independent prognostic factor in the development of oral mucositis during autologous peripheral stem cell transplantation

Oral mucositis (OM) is a frequent complication of stem cell transplantation-associated toxicity in haematological malignancies, contributing to mortality. Therapy still remains mainly supportive. We assessed risk factors in retrospective analysis of 192 autologous peripheral stem cell transplantation patients with lymphoma and multiple myeloma (MM), respectively. Futhermore, we examined the hormone levels both in serum and saliva during transplantation in 7 postmenopausal female patients with lymphoma compared to healthy controls using electrochemiluminescence immunoassay (ECLIA). Multivariable analysis revealed neutrophil engraftment (p < 0.001; p = 0.021) and female sex (p = 0.023; p = 0.038) as independent predictive factors in the combined patient group and in the lymphoma group, and neutrophil engraftment (p = 0.008) in the MM group. Of the 85 female participants 19 were pre- and 66 postmenopausal. Fifteen of the pre-, and 49 of the postmenopausal women developed ulcerative mucositis (p = 0.769), more often with lymphoma than MM (p = 0.009). Serum estrogen decreased significantly both in postmenopausal controls and transplantated patients compared to premenopausals, with no difference in saliva. Serum progesterone level was significantly (p = 0.026) elevated at day + 7 of transplantation, while salivary progesterone increased at day + 7 and + 14. Our results indicate a predominantly negative effect of female sex hormones on oral immunity with role in the aetiopathogenesis of OM.

Intraindividual Variation and Personal Specificity of Salivary Microbiota

Salivary microbiota is a typical habitat of the human microbiome. This study intended to use salivary microbiota as a model aiming to systematically address the influence of collection methods and temporal dynamics on the human microbiota compared to personal specificity. We carried out a supervised short-term longitudinal study to evaluate the influence of the change of collection methods and sampling time point on salivary microbiota in 10 systemically and orally healthy individuals with certain confounding factors (sex, oral and general health state, medication history, physical exercise, diet, and oral hygiene behavior) controlled before and during the sampling period. The microbial profiles were analyzed by 16S rDNA V3 to V4 hypervariable region amplicon sequencing. The taxonomic structure represented by the dominant species and the weighted UniFrac distance algorithm were used to demonstrate the individual specificity and the intraindividual variation introduced by the change of collection method and sampling time point. The findings suggested individual specificity existed in salivary microbiota from individuals with similar oral and general health status. The intraindividual variation brought by the change of collection method or sampling time point might introduce remarkable perturbation with the personal specificity. Insights into the intraindividual variation and personal specificity of salivary microbiota will enhance our understanding in salivary microbiota-related research. We recommend keeping collection conditions consistent within a study to avoid interference brought by the sampling. The strategy of repeated sampling at multiple time points as representative samples, as well as thorough interpretation of the complex relationships and causality between microbiome composition and disease without the interference of temporal dynamics, is optimal for research exploring the relationship between the salivary microbiome and disease.

Regulatory effect of 17β-estradiol on the expression of β-defensin-2 and proinflammatory cytokines in human oral epithelial cells

BACKGROUND

Although estrogen deficiency has been proposed as a risk factor for oral mucosal inflammatory diseases in post-menopausal women, the mechanisms involved remain unclear. This study aimed to investigate the effect of 17β-estradiol (E2) on the inflammatory response stimulated by interleukin-1 beta (IL-1β) in human oral mucosal epithelial cells (hOMECs) and its possible mechanism.

METHODS

Primary hOMECs were obtained from female infants and cultured in keratinocyte growth medium. The hOMECs at second passage were collected and stimulated by 10^-7  mol/L ICI182,780 or 10^-7  mol/L G1 for 1 hour, E2 (10^-7  mol/L, 10^-8  mol/L, 10^-9  mol/L) for 36 hour, 100 ng/mL IL-1β for 12 hours, respectively. Human beta-2 defensin (hBD-2), tumor necrosis factor-alpha (TNF)-α, IL-6, IL-8, estrogen receptor-alpha (ERα), estrogen receptor-beta (ERβ), and G protein-coupled receptor 30 (GPR30) mRNA levels and protein levels were measured by real-time quantitative polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), and Western Blot (WB), respectively.

RESULTS

Expression of hBD-2 and inflammatory cytokines increased after IL-1β stimulation, which was down-regulated by E2 pre-treatment. With ICI182,780, the suppression of E2 on hBD-2 mRNA was attenuated. With G1, the mRNA expression and protein expression of hBD-2 were reduced.

CONCLUSION

Pre-treatment of hOMECs with E2 at physiological concentrations inhibited the IL-1β-induced expression of hBD-2 and inflammatory cytokines. The protective effects of E2 suggest its potential use treating oral inflammatory diseases in clinical practice.

The influence of hormone replacement therapy on the salivary flow of post-menopausal women

The aim of this study is to investigate the influence of hormone therapy on salivary flow in menopausal women. It is a case-control study involving 86 post-menopausal women. The case group consisted of 47 women undergoing estroprogestative or estrogen hormone replacement therapy (HRT), and the control group consisted of 39 women who did not receive any HRT. All patients were submitted to a standard questionnaire, followed by total stimulated sialometry and determination of body mass index (BMI). The salivary flow was classified as follows: normal (1.0-3.0 mL/min), low (0.7-1.0 mL/min), and hyposalivation (<0.7 mL/min). The results were analyzed statistically by the chi-square test, logistic regression model, and linear regression (p < 0.05). The HRT group presented an association of protection, even after adjusting the analysis, for low salivary flow (Adjusted OR = 0.22; 95% CI = 0.05-0.88; p = 0.034), and hyposalivation (Adjusted OR = 0.30; 95% CI = 0.10-0.92; p = 0.036). The results suggest that estroprogestative therapy (β = + 0.53; p = 0.022) has greater influence on the increase of salivary flow than estrogen therapy (β = +0.35; p = 0.137). The study concludes stating salivary flow was influenced by HRT on the post-menopausal women studied.