Fluoxetine reduces periodontal disease progression in a conditioned fear stress model in rats

Periodontitis and Depressive Disorders: The Effects of Antidepressant Drugs on the Periodontium in Clinical and Preclinical Models: A Narrative Review

Background/Objectives: Several psychological conditions, including stress and depression, can adversely affect oral health; in fact, antidepressants, commonly used to treat depressive disorders, may have conflicting effects on the periodontal status of individuals. The aim of this review was to determine the effects of antidepressants on the periodontium. Methods: A literature search was conducted using electronic databases, Pubmed/MEDLINE, Cochrane Library, focusing on the use of antidepressants and their effects on periodontal health in animals or humans. Results: Seventeen articles have been included with the use of amitriptyline (two studies), desipramine (one study), imipramine (two studies), desvenlafaxine (one study), fluoxetine (six studies), venlafaxine (three studies) and tianeptine (two studies). One study evaluated several categories of antidepressants, such as selective serotonin reuptake inhibitors (SSRI), serotonin-norepinephrine reuptake inhibitors (SNRI), tricyclic, atypical and monoamine oxidase inhibitors (MAO). Most trials showed improvements in periodontal health, especially with fluoxetine, but also with imipramine, desipramine, desvenlafaxine and tianeptine; on the contrary, worsening of clinical periodontal indices and increased loss of alveolar bone were reported with venlafaxine. Conclusions: This review suggests that in the presence of comorbidity between periodontitis and depression, pharmacological treatment with SNRIs, SSRIs and mixed antidepressants is associated with improvement in periodontal parameters, except for venlafaxine. Healthcare professionals (especially oral and mental health professionals) should investigate proper adherence to medication therapy in patients with a history of periodontitis and depression. Further clinical trials are needed to confirm these results.

The effect of SSRIs on fear learning: a systematic review and meta-analysis

RATIONALE

Selective serotonin reuptake inhibitors (SSRIs) are considered first-line medication for anxiety-like disorders such as panic disorder, generalized anxiety disorder, and post-traumatic stress disorder. Fear learning plays an important role in the development and treatment of these disorders. Yet, the effect of SSRIs on fear learning are not well known.

OBJECTIVE

We aimed to systematically review the effect of six clinically effective SSRIs on acquisition, expression, and extinction of cued and contextual conditioned fear.

METHODS

We searched the Medline and Embase databases, which yielded 128 articles that met the inclusion criteria and reported on 9 human and 275 animal experiments.

RESULTS

Meta-analysis showed that SSRIs significantly reduced contextual fear expression and facilitated extinction learning to cue. Bayesian-regularized meta-regression further suggested that chronic treatment exerts a stronger anxiolytic effect on cued fear expression than acute treatment. Type of SSRI, species, disease-induction model, and type of anxiety test used did not seem to moderate the effect of SSRIs. The number of studies was relatively small, the level of heterogeneity was high, and publication bias has likely occurred which may have resulted in an overestimation of the overall effect sizes.

CONCLUSIONS

This review suggests that the efficacy of SSRIs may be related to their effects on contextual fear expression and extinction to cue, rather than fear acquisition. However, these effects of SSRIs may be due to a more general inhibition of fear-related emotions. Therefore, additional meta-analyses on the effects of SSRIs on unconditioned fear responses may provide further insight into the actions of SSRIs.

Mental health and periodontal and peri-implant diseases

Mental health disorders, particularly depression and anxiety, affect a significant number of the global population. Several pathophysiological pathways for these disorders have been identified, including the hypothalamic-pituitary-adrenal axis, autonomic nervous system, and the immune system. In addition, life events, environmental factors, and lifestyle affect the onset, progression, and recurrence of mental health disorders. These may all overlap with periodontal and/or peri-implant disease. Mental health disorders are associated with more severe periodontal disease and, in some cases, poorer healing outcomes to nonsurgical periodontal therapy. They can result in behavior modification, such as poor oral hygiene practices, tobacco smoking, and alcohol abuse, which are also risk factors for periodontal disease and, therefore, may have a contributory effect. Stress has immunomodulatory effects regulating immune cell numbers and function, as well as proinflammatory cytokine production. Stress markers such as cortisol and catecholamines may modulate periodontal bacterial growth and the expression of virulence factors. Stress and some mental health disorders are accompanied by a low-grade chronic inflammation that may be involved in their relationship with periodontal disease and vice versa. Although the gut microbiome interacting with the central nervous system (gut-brain axis) is thought to play a significant role in mental illness, less is understood about the role of the oral microbiome. The evidence for mental health disorders on implant outcomes is lacking, but may mainly be through behaviourial changes. Through lack of compliance withoral hygiene and maintenance visits, peri-implant health can be affected. Increased smoking and risk of periodontal disease may also affect implant outcomes. Selective serotonin reuptake inhibitors have been linked with higher implant failure. They have an anabolic effect on bone, reducing turnover, which could account for the increased loss.

Aggravating Effects of Psychological Stress on Ligature-Induced Periodontitis via the Involvement of Local Oxidative Damage and NF-κB Activation

Periodontitis is the leading cause of tooth loss in adults, and psychological factors play an important role in the development of periodontitis. To elucidate the adverse effects of psychological stress on the inflammatory process and redox status of periodontitis tissue, fifty male Sprague-Dawley rats were divided into the control, experimental periodontitis, psychological stress, experimental periodontitis plus psychological stress, and experimental periodontitis plus psychological stress plus fluoxetine groups. Chronic unpredictable mild stress (CUMS) was used to establish psychological stress, and silk ligature was used to induce experimental periodontitis. Four weeks later, stressed rats showed altered behaviour, serum hormone levels, and sucrose preference. More obvious alveolar bone loss and attachment loss and higher protein expressions of inflammatory cytokines were observed in the experimental periodontitis plus psychological stress group. The combination of CUMS and periodontitis had synergistic effects on increasing hypoxia-inducible factor-1α (HIF-1α) protein expression and reactive oxygen species (ROS) and malondialdehyde (MDA) contents and decreasing antioxidant enzyme activities compared with those in the stress or periodontitis groups. Moreover, psychological stress further increased p-IκBα and p-NF-κB p65 protein levels and decreased IκBα protein levels in periodontitis rats. Fluoxetine administration alleviated the adverse effects of psychological stress on the progression of periodontitis in rats. These results hint us that psychological stress could aggravate inflammation in periodontitis tissues, which may be partly due to local worsening of oxidative damage and further activation of the nuclear factor kappa-B (NF-κB) signalling pathway.

Association of different antidepressant classes with clinical attachment level and alveolar bone loss in patients with periodontitis: A retrospective study

OBJECTIVE

Our study aimed to determine the relationship of antidepressant medicine use with periodontal diseases, exploring the association of different pharmacological classes of antidepressant with observations of clinical attachment loss (CAL) and alveolar bone level (BL) in patients with periodontitis.

BACKGROUND

Existing evidence on the impact of antidepressant medication on periodontal tissues has focused on some classes only and is still unclear. Therefore, this retrospective study evaluated the association of different antidepressant classes with clinical attachment loss (CAL) and alveolar bone level (BL).

METHODS

This study was carried out in a population of patients aged ≥ 30 years old with periodontitis who sought treatment at the University of Florida from 2014 to 2018. The following variables were obtained from patients' records; usage of antidepressant medications and their pharmacological classes (selective serotonin reuptake inhibitors [SSRI], serotonin-norepinephrine reuptake inhibitors [SNRI], tricyclic, atypical, and monoamine oxidase inhibitors [MAO]), age, gender, smoking habit, mild systemic diseases, CAL, and cement-enamel junction (CEJ) and alveolar bone crest (BC) distance, defined as BL, in the Ramfjord index teeth.

RESULTS

Five hundred and eighty-two periodontitis patients were evaluated, of which 113 (19.4%) were antidepressant users. Antidepressant users exhibited significantly lower BL and fewer sites with severe CAL (≥5 mm), than non-users (p < .05). Among all single-class antidepressant users, the SSRI users showed significantly less CAL and lower BL than non-users (p < .05). Patients taking combinations of the different classes of antidepressants also showed better CAL and BL than non-users. Generalized linear models, including variables such as gender, age, systemic diseases, and smoking, demonstrated that antidepressant users were more likely to have lower mean BL and fewer sites with severe bone loss (i.e. BL > 3 and >5 mm) than non-users (p < .05).

CONCLUSIONS

Antidepressant medications were associated with higher alveolar bone level and less clinical attachment loss in patients with periodontitis. When the different classes of antidepressants were analyzed individually, only the SSRI class users and the multiple-class users showed significantly less periodontal breakdown than non-users.

The Role of the Oral Microbiota Related to Periodontal Diseases in Anxiety, Mood and Trauma- and Stress-Related Disorders

The prevalence of anxiety, mood and trauma- and stress-related disorders are on the rise; however, efforts to develop new and effective treatment strategies have had limited success. To identify novel therapeutic targets, a comprehensive understanding of the disease etiology is needed, especially in the context of the holobiont, i.e., the superorganism consisting of a human and its microbiotas. Much emphasis has been placed on the role of the gut microbiota in the development, exacerbation, and persistence of psychiatric disorders; however, data for the oral microbiota are limited. The oral cavity houses the second most diverse microbial community in the body, with over 700 bacterial species that colonize the soft and hard tissues. Periodontal diseases encompass a group of infectious and inflammatory diseases that affect the periodontium. Among them, periodontitis is defined as a chronic, multi-bacterial infection that elicits low-grade systemic inflammation via the release of pro-inflammatory cytokines, as well as local invasion and long-distance translocation of periodontal pathogens. Periodontitis can also induce or exacerbate other chronic systemic inflammatory diseases such as atherosclerosis and diabetes and can lead to adverse pregnancy outcomes. Recently, periodontal pathogens have been implicated in the etiology and pathophysiology of neuropsychiatric disorders (such as depression and schizophrenia), especially as dysregulation of the immune system also plays an integral role in the etiology and pathophysiology of these disorders. This review will discuss the role of the oral microbiota associated with periodontal diseases in anxiety, mood and trauma- and stress-related disorders. Epidemiological data of periodontal diseases in individuals with these disorders will be presented, followed by a discussion of the microbiological and immunological links between the oral microbiota and the central nervous system. Pre-clinical and clinical findings on the oral microbiota related to periodontal diseases in anxiety, mood and trauma- and stress-related phenotypes will be reviewed, followed by a discussion on the bi-directionality of the oral-brain axis. Lastly, we will focus on the oral microbiota associated with periodontal diseases as a target for future therapeutic interventions to alleviate symptoms of these debilitating psychiatric disorders.

Might anxiety disorders promote head and neck cancer development?

Cancer patients present a higher risk of experiencing anxiety disorders (AD). However, it is not clear if AD might be associated with cancer development. Thus, our study aimed to evaluate if AD might be related to head and neck squamous cell carcinoma (HNSCC) development. The combination of an applied animal basic study and a retrospective diagnostic case and control study in patients was performed. As a result, we obtained that stress reduced the locomotor activity of the animals in the group stress and stress + 4NqO (p < 0.0001). The stress showed no influence on the progression of neoplasia in mice. In the same way, the case group did not present differences in anxiety scores in comparison to control. Moreover, no association between HNSCC staging and anxiety scores was observed. In conclusion, our in vivo findings in humans and animals have shown that there is no relationship between AD and oral squamous cell carcinoma.

A meta-analysis of emotional disorders as possible risk factors for chronic periodontitis

The aim of the present meta-analysis was to evaluate scientific evidence on the association between emotional disorder (depression and anxiety) and chronic periodontitis. An overall electronic literature search in PubMed, ISI Web of Science, Cochrane Library, and China National Knowledge Infrastructure was undertaken up to November 2017. Newcastle-Ottawa scale was applied to ascertain the validity of each eligible study. Stata statistical software was used to perform meta-analysis. The strength of the association between periodontitis and emotional disorder was measured by odds ratios (ORs) with their 95% confidence intervals (95% CIs). Subgroup analysis and sensitivity analysis were performed. Publication bias was assessed through funnel plots and Begger's test. A total of 14 eligible articles were included in the meta-analysis, 6 of them were focused exclusively on depression, whereas 8 studies investigated both depression and anxiety. There was significant association between emotional disorder and chronic periodontitis (OR = 1.54, 95% CI = 1.27-1.86). Sensitivity analyses confirmed the stability of the present results. No evidence of asymmetry was observed in Begger's test. This meta-analysis demonstrates significant association between emotional disorder (including anxiety and depression) and chronic periodontitis. Nevertheless, the result should be interpreted with caution because of the potential bias and confounding in the included studies.

Use of antidepressive agents as a possibility in the management of periodontal diseases: A systematic review of experimental studies

Antidepressant agents have anti-inflammatory functions that could be interesting as adjuvants in periodontal therapy. The aim of the present study was to analyze the effect of antidepressive drugs in the management of periodontal disease. The MEDLINE, Scopus, Embase, LILACS, and SciELO databases were searched. To be included, the studies had to be experimental studies; randomized, controlled; double-blinded; or blinded studies. A total of 565 articles were initially searched, of which five were selected for the systematic review. All studies used rats, and three different drugs were evaluated: tianeptine, venlafaxine, and fluoxetine. Two of these studies evaluated the effect of antidepressive agents in rats submitted to both ligature-induced periodontitis and depression models, showing that depressive rats had greater alveolar bone loss (ABL). Only the venlafaxine study was not able to find any significant ABL reduction in the group that used this antidepressive drug. The other four studies showed statistically-significant differences, favoring the group with the antidepressant agent. Treatments that are able to modulate the brain-neuroendocrine-immune system could be used as an adjuvant to periodontal disease management. However, studies on humans and animals are scarce, limiting the conclusion of a positive effect in the present systematic review.

Impact of post-traumatic stress disorder on oral health

BACKGROUND

The stress experienced as an intense and traumatic event can increase the odds of orofacial pain, affect the biomechanics of masticatory system and compromise the periodontal health. This study was conducted to investigate the impact of post-traumatic stress disorder (PTSD) on oral health.

METHODS

A case-control study with a convenience sample was designed. Probing pocket depth (PPD), clinical attachment level (CAL), bleeding on probing, and plaque were recorded at 6 sites per tooth. A visual analog scale (VAS) was used to evaluate the pain after probing. The Research Diagnostic Criteria for Temporomandibular Disorders Axis II (RDC/TMD Axis II) and Structured Clinical Interview (DSM-IV) were also applied. The final sample comprised 38 PTSD patients and 38 controls.

RESULTS

Patients with PTSD had a higher degree of chronic pain, more depression and nonspecific physical symptoms (including and excluding pain) compared with the control group (Fisher exact test p < 0.001, and Chi-squared test, p < 0.001, < 0.001, < 0.001, respectively). Patients with PTSD also had more pain after periodontal probing compared with controls (Mann-Whitney, p = 0.037). The prevalence of sites with CAL or PPD ≥ 4, ≥ 5, ≥ 6 were not different between the groups. Age was associated with moderate periodontitis (multivariable logistic regression model, OR = 3.33, 95% CI = 1.03-10.75, p = 0.04).

LIMITATION

The severity of PTSD precluded an ample sample size.

CONCLUSIONS

Patients with PTSD presented a worse RDC/TMD Axis II profile, more pain after periodontal probing, and no difference related to periodontal clinical parameters. More studies are needed to confirm these findings.

The involvement of cannabinoids and mTOR in the reconsolidation of an emotional memory in the hippocampal-amygdala-insular circuit

Memory reconsolidation is the process in which reactivated long-term memory becomes transiently sensitive to amnesic agents. We evaluated the ability of post reactivation administration of the mTOR inhibitor rapamycin, separately and in combination with the cannabinoid CB1/2 receptor agonist WIN55,212-2 (WIN), given systemically or specifically into the hippocampal CA1 area, basolateral amygdala (BLA) or insular cortex (IC), to reduce inhibitory avoidance fear in rats. Systemic administration of rapamycin after reactivation of fear memory impaired reconsolidation and facilitated extinction. A combined treatment with WIN and rapamycin resulted in similar effects. WIN injected systemically facilitated extinction, with no effect on reconsolidation. WIN alone and with rapamycin also decreased anxiety-like behavior. Further, when spontaneous recovery was tested, the WIN+rapamycin group did not demonstrate recovery of fear which can occur spontaneously after the passage of time. Rapamycin and WIN had differential effects on reconsolidation and extinction when microinjected into the CA1, BLA and IC. Furthermore, exposure to shock increased p70s6K activation in the BLA, indicating activation by mTOR. Treatment with rapamycin, WIN or WIN+rapamycin decreased activation and there was a strong positive correlation between fear retrieval and p70s6K activation in the BLA, suggesting that enhanced fear retrieval is associated with enhanced p70s6K activation. Taken together, the results suggest that rapamycin or a combined treatment that involves blocking mTOR and activating cannabinoids may be a promising pharmacological approach for the attenuation of reactivated emotional memories, and thus, it could represent a potential treatment strategy for disorders associated with traumatic memories.

The effect of an inhibitor of gut serotonin (LP533401) during the induction of periodontal disease

BACKGROUND AND OBJECTIVE

LP533401 is an inhibitor of tryptophan hydroxylase 1, which regulates serotonin production in the gut. Previous work indicates that LP533401 has an anabolic effect in bone. Thus, we hypothesized that inhibition of gut serotonin production may modulate the host response in periodontal disease. In this study, we aimed to analyze the effects of LP533401 in a rat periodontitis model to evaluate the role of gut serotonin in periodontitis pathophysiology.

MATERIAL AND METHODS

Twenty-four rats were divided into three groups: treated group (T: ligature-induced periodontal disease and LP533401, 25 mg/kg/d) by gavage; ligature group (L: ligature-induced periodontal disease only); and control group (C: without ligature-induced periodontal disease). After 28 d, radiographic alveolar bone support was measured on digital radiographs, and alveolar bone volume fraction, tissue mineral density and trabeculae characteristics were quantified by microcomputed tomography in the right hemi-mandible. Left hemi-mandibles were decalcified and alveolar bone loss, attachment loss and area of collagen in the gingiva were histologically analyzed.

RESULTS

Significant difference between the L and C groups was found, confirming that periodontal disease was induced. We observed no difference between the T and L groups regarding alveolar bone destruction and area of collagen.

CONCLUSION

LP533401 (25 mg/kg/d) for 28 d does not prevent bone loss and does not modulate host response in a rat model of induced periodontal disease.

Effect of Fluoxetine on Periodontal Status in Patients With Depression: A Cross-Sectional Observational Study

BACKGROUND

Fluoxetine, a selective serotonin reuptake inhibitor, has been reported to reduce periodontal disease severity in a rat ligature-induced periodontitis model. The objective of the present study is to investigate the influence of fluoxetine intake on periodontal parameters in patients with periodontitis with clinical depression.

METHODS

A sample of 236 patients with chronic periodontitis and clinical depression were assessed for clinical parameters of periodontal disease. Of these, 115 patients were taking fluoxetine (20 mg/day) for ≥2 months, and 121 patients were not. Participants taking fluoxetine were further analyzed for correlation between duration of drug intake and periodontal parameters.

RESULTS

All periodontal parameters, except plaque index, were significantly lower in participants taking fluoxetine (P <0.01). Partial correlation analysis, adjusted for confounders, revealed a significant and negative correlation between duration of fluoxetine intake and attachment loss (AL) (R(2) = -0.321, P <0.05). Logistic regression analysis revealed that fluoxetine intake was associated with a lower risk of having AL ≥3 (odds ratio [OR] = 0.55, 95% confidence interval [CI] = 0.31 to 0.96) and lower odds of increased bleeding on probing (BOP) percentage values (OR = 0.62, 95% CI = 0.34 to 0.97).

CONCLUSION

In this observational study, use of fluoxetine was associated with lower BOP percentages and reduced AL.