The concentration of salivary steroid hormones and the prevalence of gingivitis at puberty

(R)evolution of the Standard Addition Procedure for Immunoassays

A new method to transfer the standard addition procedure for concentration determination to immunoassays with non-linear calibration curves was developed. The new method was successfully applied to simulated data and benchmarked against a state-of-the-art algorithm, showing a significantly improved performance with improvement factors between 2 and 192. The logit function was used to transform the immunoassay signal response of test samples spiked with known analyte concentrations. The relationship between logit(signal) and log-transformed estimated total analyte concentration is linear if the estimated total analyte concentration is correct. Finally, the new method was validated experimentally using different assays in varying, relevant complex matrices, such as serum, saliva, and milk. Different concentrations of testosterone and amitriptyline between 0.05 and 3.0 µg L-1 were quantified using a binding inhibition assay in combination with reflectometric interference spectroscopy (RIfS) as the transduction principle. The sample concentration was calculated using a numerical method. Samples could be quantified with recoveries between 70 and 118%. The standard addition method accounts for individual matrix interference on the immunoassay by spiking the test sample itself. Although the experiments were carried out using RIfS, the method can be applied to any immunoassay that meets the analytical requirements.

Microbiomes in supragingival biofilms and saliva of adolescents with gingivitis and gingival health

BACKGROUND

Important alterations exist in the microbiomes of supragingival biofilm and saliva samples from adolescent patients developing induced or spontaneous gingivitis relative to healthy controls. These and the relationships to dental health are not fully understood yet.

SUBJECTS AND METHODS

Supragingival biofilm samples (n = 36) were collected from the teeth of 9 adolescents with gingivitis induced by orthodontic appliances, as well as dental plaques (n = 40) from 10 adolescents with spontaneous gingivitis, in addition to similar samples (n = 36) from 9 healthy controls. The bacterial metagenomes were analyzed by 16S rRNA gene amplicon sequencing. Salivary microbiomes of the same persons were characterized by shotgun metagenome sequencing. The data sets were examined using advanced bioinformatics workflows and two reference databases.

RESULTS

The composition and diversity of bacterial communities did not differ extensively among the three study groups. Nevertheless, the relative abundances of the genera Fusobacterium, Akkermansia, Treponema, and Campylobacter were prominently higher in gingivitis patients versus controls. In contrast, the genera Lautropia, Kingella, Neisseria, Actinomyces, and Rothia were significantly more abundant in controls than in either of the two gingivitis groups.

CONCLUSIONS

The abundance pattern of certain taxa rather than individual strains shows characteristic features of potential diagnostic value. Stringent bioinformatics treatment of the sequencing data is mandatory to avoid unintentional misinterpretations.

"Low Testosterone Levels in Body Fluids Are Associated With Chronic Periodontitis"

There is a debate over the association between low testosterone levels in body fluids and the occurrence of chronic periodontitis (CP). The aim of the present systematic review was to assess whether low testosterone levels in body fluids reflect CP. In order to identify studies relevant to the focus question: “Is there a relationship between low testosterone levels in body fluids and CP?” an electronic search without time or language restrictions was conducted up to June 2016 in indexed databases using different keywords: periodontitis, chronic periodontitis, periodontal diseases, testosterone, and gonadal steroid hormones. A total of eight studies were included in the present systematic review. The number of study participants ranged from 24 to 1,838 male individuals with ages ranging from 15 to 95 years. Seven studies measured testosterone levels in serum, two studies in saliva, and one study in gingiva. Four studies reported a negative association between serum testosterone levels and CP. Two studies reported a positive association between decreased testosterone levels in serum and CP. Increased levels of salivary testosterone among patients with CP were reported in one study; whereas one study reported no significant difference in the concentration of salivary testosterone between patients with and without CP. One study identified significant increase in the metabolism of testosterone in the gingiva of patients with CP. Within the limits of the evidence available, the relationship between low testosterone levels and CP remains debatable and further longitudinal studies and control trials are needed.

The Effect of Fixed Orthodontic Appliances and Fluoride Mouthwash on the Oral Microbiome of Adolescents - A Randomized Controlled Clinical Trial

While the aesthetic effect of orthodontic treatment is clear, the knowledge on how it influences the oral microbiota and the consequential effects on oral health are limited. In this randomized controlled clinical trial we investigated the changes introduced in the oral ecosystem, during and after orthodontic treatment with fixed appliances in combination with or without a fluoride mouthwash, of 10–16.8 year old individuals (N = 91). We followed several clinical parameters in time, in combination with microbiome changes using next-generation sequencing of the bacterial 16S rRNA gene. During the course of our study, the oral microbial community displayed remarkable resilience towards the disturbances it was presented with. The effects of the fluoride mouthwash on the microbial composition were trivial. More pronounced microbial changes were related to gingival health status, orthodontic treatment and time. Periodontal pathogens (e.g. Selenomonas and Porphyromonas) were highest in abundance during the orthodontic treatment, while the health associated Streptococcus, Rothia and Haemophilus gained abundance towards the end and after the orthodontic treatment. Only minor compositional changes remained in the oral microbiome after the end of treatment. We conclude that, provided proper oral hygiene is maintained, changes in the oral microbiome composition resulting from orthodontic treatment are minimal and do not negatively affect oral health.

Effects of sex hormones on production of interleukin-1 by human peripheral monocytes

BACKGROUND

Interleukin-1 (IL-1) is a potent mediator of inflammation and is known to induce bone resorption. We studied the effects of sex hormones on the function of human monocytes and demonstrated that prostaglandin E2 (PGE2) production was enhanced by progesterone and estradiol. As PGE2 has been shown to suppress the production of IL-1 by monocytes, it was speculated that sex hormones also modify the production of IL-1 by regulating PGE2 production. Thus, the effects of sex hormones on the production of IL-1 from human peripheral monocytes and the influence of PGE2 were investigated.

METHODS

Mononuclear leukocytes were obtained from 22 healthy adults. Progesterone, 17-beta estradiol (estradiol), and testosterone were used as representative sex hormones. Monocytes were incubated at 37 degrees C in air with 5% CO2 for 24 hours in RPMI 1640 medium with sex hormones at the designated concentrations. LPS (Salmonella typhimurium) was used to stimulate the monocytes at a concentration of 10 microg/ml. The concentrations of IL-1alpha and IL-1beta in the medium were determined by enzyme-linked immunosorbent assay kits. The concentration of PGE2 was determined using a direct radio-immunoassay kit. Indomethacin was used to inhibit the synthesis of PGE2 and eliminate its effect on the production of IL-1.

RESULTS

Estradiol at concentrations of 0.04 ng/ml or more significantly reduced both IL-1alpha and IL- 1beta production. Progesterone also reduced IL-1alpha and IL-1beta production significantly at concentrations of 0.1 ng/ml or more and 0.02 ng/ml or more, respectively. The reductions in IL- 1alpha and IL-1beta production by sex hormones were not affected by addition of indomethacin.

CONCLUSIONS

Estradiol and progesterone inhibited the production of IL-1 from human peripheral monocytes. The inhibition was not the result of enhanced production of PGE2. Under conditions in which sex hormone levels are low, monocytes produce IL- more readily in response to stimulation by LPS than high levels of such hormones. Low concentrations of sex hormones may be considered as one of the risk factors for periodontitis.

Physiological concentration of estradiol inhibits polymorphonuclear leukocyte chemotaxis via a receptor mediated system

Estrogen exhibits a variety of actions, including immuno-modulatory effects, in vivo and in vitro. The mechanism by which estrogen exerts its anti-inflammatory effect is not yet understood. We investigated the possible mechanisms of estradiol acting via the polymorphonuclear leukocytes (PMNs), which are important in the immune response. The agent, 17 beta-estradiol, but not 17 alpha-estradiol, significantly reduced PMNs chemotaxis to FMLP in a dose-dependent manner (control vs estrogen 10(-10)-(-6) M, P < 0.05). Physiological concentrations of estradiol significantly reduced the chemotaxis of PMNs (10(-10) mol). Pre-incubation with clomiphene or tamoxifen which are estrogen receptor antagonists, eliminated the inhibitory effect of 17 beta-estradiol on the chemotaxis of PMNs, restoring it to the control level. These observations suggest that 17 beta-estradiol suppressed the chemotaxis of PMNs by a receptor-dependent mechanism. In addition, the level of estradiol in human plasma, which PMNs were drawn, showed a close, inverse correlation with the PMNs chemotaxis to FMLP (r = -0.821 p < 0.001). Estrogen may modify the activity of neutrophils during the normal menstrual cycle, not only during pregnancy, and influence inflammation.

Effects of sex hormones on production of prostaglandin E2 by human peripheral monocytes

The effects of sex hormones on the vitro production of prostaglandin (PG) E2 by monocytes were investigated. Monocytes were obtained from heparinized peripheral blood of healthy adults and incubated for 24 hours with lipopolysaccharide (LPS) and sex hormones. After incubation, the medium was assayed for PGE2 by means of radioimmunoassay. PGE2 production by monocytes was enhanced by progesterone. Estradiol reduced PGE2 production at 0.4 ng/ml, but enhanced it at 20 ng/ml. Testosterone reduced PGE2 production. The reduced PGE2 production by monocytes treated with 0.4 ng/ml of estradiol was restored to the control level by addition of progesterone at 20 ng/ml. These results suggest that sex hormones may modulate gingival inflammation mediated by PGE2.

Effects of sex hormones on chemotaxis of human peripheral polymorphonuclear leukocytes and monocytes

The effects of sex hormones on the in vitro chemotaxis of polymorphonuclear leukocytes (PMNs) and monocytes were investigated using fMLP as the chemoattractant. PMNs, monocytes, and plasma were obtained from heparinized peripheral blood of healthy adults. Chemotaxis of PMNs or monocytes treated with sex hormones were tested using 48-well chemotaxis microchambers. The correlation between sex hormone levels in plasma and the chemotactic ability of PMNs from the same donor was also investigated. The chemotaxis of PMNs was enhanced by progesterone, while it was reduced by estradiol. Random migration of PMNs was also enhanced by progesterone and reduced by estradiol. The effect of estradiol on PMN chemotaxis was inhibited by addition of antiestrogens or progesterone. Testosterone did not have a measurable effect on PMN chemotaxis. A significant positive correlation was found between the concentration of progesterone in plasma of females and PMN chemotactic ability in vitro. For males, there was no significant relationship between plasma levels of sex hormones and PMN chemotactic ability. Estradiol and testosterone levels in plasma did not correlate with PMN chemotactic ability. Sex hormones had no effect on the chemotaxis of monocytes. These results suggest that the altered PMN chemotaxis associated with gingival inflammation may be due to the effects of sex hormones.