Association between the use of serotonin receptor 2A-blocking antidepressants and joint disorders

Mood disorders and 5-HTR2A genetic variants - the moderator effect of inflammation on expression of affective polarity phenotype

BACKGROUND

Although repeatedly confirmed, the molecular nature of gene-environment (GxE) interactions has rarely been investigated in the clinical context of mood disorders. This study assesses the relationship between HTR2A genetic variants and the modulatory effect of inflammation in a collective cohort of patients with major depressive disorder (MDD) and bipolar disorder (BD), as a unified group with two distinct phenotypes.

METHODS

The study included 138 patients with acute mood episodes (BD = 83; MDD = 55). HTR2A rs6313 and rs6314 genotyping was performed while measuring platelet-derived indicators of inflammation (platelet count (PLT), mean platelet volume (MPV), plateletcrit, and platelet distribution width) and the MPV/PLT ratio.

RESULTS

The HTR2A rs6313 variant is a significant predictor of the polarity phenotype in mood disorders, with the MPV/PLT ratio moderating this relationship, but only under low-inflammatory conditions. In more pronounced inflammatory states, genetic influences lose their predictive role.

CONCLUSIONS

To our knowledge, this is the first study to investigate the complex interplay between platelet-derived indicators of inflammation and HTR2A variants in the context of mood disorders. Without pro-inflammatory conditions, mood disorders seem to be more genetically determined. Under pro-inflammatory conditions, phenotypic presentation is less dependent on genetic factors. GxE interactions in mood disorders are multifaceted, context-dependent and relevant for assessing their clinical presentation and course.

Psilocybin, a Naturally Occurring Indoleamine Compound, Could Be Useful to Prevent Suicidal Behaviors

The available interventions for people who are at risk of suicide have limited efficacy. Recently, research on new mental health treatments has started to consider psychedelic compounds, particularly psilocybin, a molecule with a few thousand years of history of use in human societies. The possible effects of psilocybin on suicidal ideation and behaviors have not been specifically studied yet; however, the current knowledge on the suicidal process and the available data on es/ketamine suggest that psylocibin could be used to modulate the thoughts and behavioral patterns in individuals who are at risk of suicidal behaviors. Here, we summarize the available evidence on the possible mechanisms underlying psilocybin positive effects on suicide risk. Major pathways related to suicidal behaviors that might be modulated by psylocibin include serotonin receptors. Specifically, psylocibin directly stimulates the serotonin 2A receptor (5HT_2A), targeting the inflammatory and oxidative stress pathways and leading to a rapid increase in brain plasticity and inflammation suppression and increases in cognitive flexibility, spirituality, and empathy. We also present preliminary epidemiological data and provide a rationale for studying psilocybin in individuals with suicidal ideation or who are at risk of suicidal behaviors. This review presents a framework to understand the basis for psilocybin use in individuals who are at risk of suicidal behaviors and calls for clinical studies.

Serotonin 2A Receptor Inverse Agonist as a Treatment for Parkinson's Disease Psychosis: A Systematic Review and Meta-analysis of Serotonin 2A Receptor Negative Modulators

BACKGROUND

There is uncertainty about the efficacy and tolerability of serotonin 2A (5-HT2A) receptor negative modulators for Parkinson's disease psychosis (PDP).

OBJECTIVE

This is the first meta-analysis of randomized placebo-controlled trials (RCTs) testing negative modulators of the 5-HT2A receptor as a treatment for PDP.

METHODS

The primary outcome was the Scale for Assessment of Positive Symptoms (SAPS)-hallucinations (H) and -delusions (D) scores (SAPS-H+D). Other outcome measures were SAPS-H, SAPS-D, the Unified Parkinson's Disease Rating Scale Part II and III (UPDRS-II+III), discontinuation rates, and individual adverse events.

RESULTS

Four RCTs were identified that met inclusion criteria, all assessing the 5-HT2A inverse agonist pimavanserin (including 417 drug-treated and 263 placebo-treated PDP patients). Pimavanserin significantly decreased SAPS-H+D scores compared to placebo [weighted mean differences (WMD) = -2.26, 95% confidence interval (95% CI) = -3.86 to -0.67, p = 0.005, I2 = 30% , N = 4 studies, n = 502 patients]. Moreover, pimavanserin was superior to placebo for reducing SAPS-H (WMD = -2.15, 95% CI = -3.45 to -0.86, p = 0.001, I2 = 0% , N = 2, n = 237) and SAPS-D scores (WMD = -1.32, 95% CI = -2.32 to -0.32, p = 0.010, I2 = 0% , N = 2, n = 237). Pimavanserin was associated with less orthostatic hypotension than placebo (risk ratio = 0.33, 95% CI = 0.15-0.75, p = 0.008, I2 = 0% , number needed to harm = 17, p = 0.01, N = 3, n = 476). There were no significant differences in rates of all-cause discontinuation, adverse events, and death, UPDRS-II+III scores, and incidences of individual adverse events (other than orthostatic hypotension) between pimavanserin and placebo groups.

CONCLUSIONS

Pooled RCT results suggest that pimavanserin is beneficial for the treatment of PDP and is well tolerated. We did not identify other negative modulators of the 5-HT2A receptor for the treatment of PDP.

Investigation of the role of endosomal Toll-like receptors in murine collagen-induced arthritis reveals a potential role for TLR7 in disease maintenance

Introduction

Endosomal toll-like receptors (TLRs) have recently emerged as potential contributors to the inflammation observed in human and rodent models of rheumatoid arthritis (RA). This study aims to evaluate the role of endosomal TLRs and in particular TLR7 in the murine collagen induced arthritis (CIA) model.

Methods

CIA was induced by injection of collagen in complete Freund's adjuvant. To investigate the effect of endosomal TLRs in the CIA model, mianserin was administered daily from the day of disease onset. The specific role of TLR7 was examined by inducing CIA in TLR7-deficient mice. Disease progression was assessed by measuring clinical score, paw swelling, serum anti-collagen antibodies histological parameters, cytokine production and the percentage of T regulatory (T_reg) cells.

Results

Therapeutic administration of mianserin to arthritic animals demonstrated a highly protective effect on paw swelling and joint destruction. TLR7^-/- mice developed a mild arthritis, where the clinical score and paw swelling were significantly compromised in comparison to the control group. The amelioration of arthritis by mianserin and TLR7 deficiency both corresponded with a reduction in IL-17 responses, histological and clinical scores, and paw swelling.

Conclusions

These data highlight the potential role for endosomal TLRs in the maintenance of inflammation in RA and support the concept of a role for TLR7 in experimental arthritis models. This study also illustrates the potential benefit that may be afforded by therapeutically inhibiting the endosomal TLRs in RA.

Immunomodulatory effect of sertraline in a rat model of rheumatoid arthritis

OBJECTIVE

Previous studies suggest that selective serotonin reuptake inhibitors (SSRIs) modulate immune system functionality. SSRIs are the preferred treatment for major depressive disorder (MDD). A high rate of MDD is observed in rheumatoid arthritis (RA) patients. The aim of this study was to evaluate immunological effects of SSRIs in a rat model of RA.

METHODS

Adjuvant arthritis was induced in 8-week-old Lewis rats; in the first set of experiments following the induction, 15.3 or 30.6 mg/kg of sertraline was daily injected into the ankle joint of the left rear leg. Clinical disease activity was evaluated and the findings compared with the 3 untreated legs and with control groups given methotrexate (MTX) or vehicle only at the same site. In a second set of experiments, the effect of 5, 25 and 50 mg/kg daily oral sertraline was evaluated in the same rat model. Splenocyte viability and inflammatory mediators were evaluated.

RESULTS

The sertraline-treated rats showed a significant reduction in clinical arthritis compared to controls, at all doses given, accompanied by a significant increase in interleukin 10 and a decrease in tumor necrosis factor-α levels and cycloxygenase-2 production, without lymphotoxicity. There was no significant difference from MTX, the first-line treatment for RA patients. Oral sertraline had a significant anti-inflammatory effect at all doses. There was no treatment × time effect.

CONCLUSION

The beneficial effects of sertraline in this rat model of arthritis have clinical implications for its use in humans. Large-scale clinical efficacy trials are needed.

Sustained remission of rheumatoid arthritis with a specific serotonin reuptake inhibitor antidepressant: a case report and review of the literature

Introduction

The mainstay of pharmacologic therapy for rheumatoid arthritis includes the use of disease-modifying agents like sulfasalazine and methothrexate, and more recently, anti-tumor necrosis factor-α agents. Depression remains a major co-morbidity in patients with rheumatoid arthritis and is thought to contribute to disability and mortality in these patients. Evidence now suggests that a biologic link exists between substrates responsible for inflammatory conditions and mood disorders. Most of this evidence comes from preclinical studies. Nevertheless, more research into this area is helping us to understand the possible mechanisms through which these conditions interact with each other.

Case presentation

We describe a 60-year-old Indian man with rheumatoid arthritis diagnosed 15 years ago who had minimal response to multiple therapies with disease-modifying agents and whose arthritis symptoms surprisingly remitted when he was started on a specific serotonin reuptake inhibitor antidepressant, three years ago, for co-morbid major depression. This remission has been maintained with this medication, and the patient is currently not taking any antirheumatoid medications.

Conclusion

Possible mechanisms linking substrates of mood disorders and inflammation are reviewed in this case report, particularly the serotonergic system. Evidence seems to suggest a significant interaction between the serotonergic systems and inflammation. This interaction seems to be bidirectional. An understanding of this relation is most important to gain insight not only into pathophysiological mechanisms underlying this condition, but also into how treatments for these conditions may complement each other and possibly provide greater therapeutic options in both of these disabling conditions.