The gender difference of selective serotonin reuptake inhibitor, fluoxetine in adult rats with stress-induced gastric ulcer

Idiopathic Gastric Antral Ulcers

A Japanese woman presented with gastric antral ulcers accompanied by erosion and edema, demonstrating a chronic pattern of improvement and recurrence for more than six years. The patient had no relevant treatment history, and Helicobacter pylori infection was ruled out. Other potential etiologies contributing to gastric ulcers were eliminated on the basis of endoscopic biopsy and blood laboratory findings. Consequently, the patient was diagnosed with idiopathic gastric antral ulcer. This disease is often overlooked, and the chronological endoscopic images provided in this report can be used as a reference.

DUOX2, a common modulator in preventive effects of monoamine-based antidepressants on water immersion restraint stress- and indomethacin- induced gastric mucosal damage

Multiple kinds of monoamine-based antidepressants have been shown prophylactic effects in experimentally induced gastric ulcer. The loss of redox homeostasis plays a principle role in the development of peptic mucosal damage. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases are one of the most important sources of reactive oxygen species within the gastrointestinal tract. It is unclear whether there are some common NADPH oxidases modulated by monoamine-based antidepressants in different gastric mucosal damage models. We explored the effects of selective serotonin-norepinephrine reuptake inhibitor (SNRI) duloxetine on the reactive oxygen species production and antioxidant capacity in the gastric mucosa of water immersion restraint (WIRS) or indomethacin treated rats, and examined the role of NADPH oxidases in the protective effects. Pretreated duloxetine prevented the increase of gastric mucosal NADPH oxidase activity and NADPH oxidase inhibitor apocynin dose-dependently protected gastric mucosa from damage by the two factors. Furthermore, dual oxidase 2 (DUOX2) and NADPH oxidase4 (NOX4) are involved in the protective effects of duloxetine in both models. We then examined NADPH oxidases expression modulated by the other monoamine-based antidepressants including selective serotonin reuptake inhibitor (SSRIs) fluoxetine, tricyclic agent (TCAs) amitriptyline and monoamine oxidase inhibitor (MAOs) moclobemide in the two models, and all the three antidepressants reduced the DUOX2 expression in the gastric mucosa. So DUOX2 was a common modulator in the preventive effects of all the monoamine-based antidepressants on WIRS- and indomethacin-induced gastric lesion. Our work provided a peripheral joint molecular target for monoamine modulatory antidepressants, which may be helpful to reveal the mechanisms of this kind of drugs more than monoamine regulation.

Redox metabolism modulation as a mechanism in SSRI toxicity and pharmacological effects

Depressive disorders are amongst the greatest mental health challenges, with an increasing number of patients being diagnosed each year. Though it has not yet been fully elucidated, redox metabolism imbalances and oxidative stress seem to play a major role in the pathogenesis of depressive disorders. Selective serotonin reuptake inhibitors (SSRIs) are the most prescribed antidepressants, considered to have a better tolerability. However, several adverse effects have been reported and the mechanisms involved in their pharmacological activity are not entirely understood. SSRIs have been shown to influence the redox metabolism, which could be involved in their toxicity and pharmacological effects. A comparative analysis of published in vivo and in vitro data regarding the activity of SSRIs on the redox metabolism pathways has been performed in this paper, with an emphasis on mechanistical aspects. Furthermore, a comparison between oxidative stress biomarker levels reported by different studies was attempted. The reviewed data point towards both pro- and antioxidant effects of SSRIs, dependent on tissue/cell type and dose/concentration, suggest a redox modulating potential of these compounds. In hepatic and testicular tissue, the majority of reviewed studies reported pro-oxidant effects, with possible implications towards the hepatotoxicity and sexual dysfunction that were reported following SSRI treatment; while in brain, the most common findings were antioxidant effects that could partially explain their antidepressant activity. However, given the heterogeneity of the reviewed data, further research is needed to fully understand the impact of SSRIs on redox metabolism and its implications.

Selective serotonin reuptake inhibitor fluvoxamine ameliorates stress- and NSAID-induced peptic ulcer possibly by involving Hsp70

Background Selective serotonin reuptake inhibitors (SSRIs) have recently become potential candidates for a new therapeutic approach to ulcer and gastric bleeding. Heat shock protein 70 (Hsp70) plays an important role in cellular resistance to nonsteroidal anti-inflammatory drugs (NSAIDs). However, there is lack of evidence that fluvoxamine recruits Hsp70 to affect stress-induced gastric ulcer. Therefore, we investigated the effect of fluvoxamine on NSAID- and stress-induced gastric ulcer and the possible involvement of Hsp70. Methods ICR mice were used in the study. Stress induction was made by the water-immersion-plus-restraint method. NSAID-induced gastric ulcer was produced by oral administration of indomethacin. Fluvoxamine was given orally 30 min before stress induction and indomethacin treatment. Results Stress and indomethacin treatment significantly increased the ulcer index and intraluminal bleeding score. Stress and indomethacin treatment also significantly increased the expression of Hsp70. Fluvoxamine significantly decreased the ulcer index and intraluminal bleeding in both ulcer models. Moreover, fluvoxamine further increased the expression of Hsp70 in the gastric tissue of stress- and indomethacin-treated mice. Conclusions Our results indicate that fluvoxamine may have a protective effect against stress- as well as NSAID-induced gastric ulcer. In addition, the present study suggests the possible involvement of Hsp70 in the amelioration of gastric ulcer by fluvoxamine.

Convergence of glycogen synthase kinase 3β and GR signaling in response to fluoxetine treatment in chronically stressed female and male rats

Accumulating evidence strongly suggest that impaired glucocorticoid receptor (GR) signaling is involved in stress-related mood disorders, and nominate GR as a potential target for antidepressants (ADs). It is known that different classes of ADs affects the GR action via modifying its phosphorylation, while the mechanism through which ADs alter GR phosphorylation targeted by GSK3β, a kinase modulated via serotonin neurotransmission, are unclear. On this basis, we investigated whether GSK3β-GR signaling could be a convergence point of fluoxetine action on brain function and behavior, by examining its effect on GSK3β targeted-GR phosphorylation on threonine 171 (pGR171), and expression of GR-regulated genes in the hippocampus of female and male rats exposed to chronic isolation stress. Stress induced sex-specific GSK3β-targeted phosphorylation of pGR171 in the nucleus of the hippocampus of stressed animals. Namely, while in females stress triggered coupled action of GSK3β-pGR171 signaling, in males changes in pGR171 levels did not correspond to GSK3β activity. On the other hand, fluoxetine managed to up-regulate this pathway in sex-unbiased manner. Furthermore, fluoxetine reverted stress-induced changes in most of the analyzed genes in males, CRH, 5-HT1a and p11, while in females its effect was limited to CRH. These data further suggest that pGR171 signaling affects cellular localization of GR in response to chronic stress and fluoxetine in both sexes. Collectively, our results describe a novel convergence point between GR signaling and GSK3β pathway in rat hippocampus in response to stress and fluoxetine in both sexes and its involvement in fluoxetine-regulated brain function in males.

Vanillin abrogates ethanol induced gastric injury in rats via modulation of gastric secretion, oxidative stress and inflammation

Vanillin is commonly used as an additive in food, medicine and cosmetics, but its effect has not yet been studied in gastric injury. Therefore the effect of vanillin was studied in experimental gastric ulcer. Gastric secretion and acidity were studied in pylorus ligated rats. Ulcer index, levels of gastric mucus, malondialdehyde (MDA), myeloperoxidase activity (MPO), expression of nuclear factor kappa B (NF-κB) p65, and histopathological changes were determined in ethanol induced gastric ulcer. Pre treatment with vanillin significantly reduced gastric secretion (P < 0.001) and acidity (P < 0.0001) and gastric ulcer index scores (P < 0.001). and augmented the gastric mucosal defense. Vanillin significantly restored the depleted gastric wall mucus levels (P < 0.0001) induced by ethanol and also significantly attenuated ethanol induced inflammation and oxidative stress by the suppression of gastric MPO activity (P < 0.001), reducing the expression of NF-κB p65 and the increased MDA levels (P < 0.001). Vanillin was also effective in alleviating the damage to the histological architecture and the activation of mast cells induced by ethanol.

Together the results of this study highlight the gastroprotective activity of vanillin in gastric ulcers of rats through multiple actions that include inhibition of gastric secretion and acidity, reduction of inflammation and oxidative stress, suppression of expression of NF-κB, and restoration of the histological architecture.

Antidepressants and Gastric Cancer: A Nationwide Population-Based Nested Case-Control Study

BACKGROUND

To our knowledge, no epidemiological study has reported on whether an association between antidepressant exposure and gastric cancer exists. Herein, we aim to investigate the possible association between antidepressant exposure and gastric cancer incidence.

METHODS

Using a nested case-control design, we identified 26289 cases with gastric cancer and 127984 controls from Taiwan's National Health Insurance Research Database (NHIRD). The data were analyzed using a conditional logistic regression model adjusting for possible confounding variables.

RESULTS

We found antidepressant use did not increase the risk of gastric cancer. The lack of an association between antidepressant prescription and elevated gastric cancer incidence was apparent for across selective serotonin-reuptake inhibitors (SSRIs), tricyclic agents (TCAs), serotonin-norepinephrine reuptake inhibitors (SNRIs), reversible inhibitors of monoamine oxidase A (RIMA), trazodone, mirtazapine and bupropion. There were slightly decreased gastric cancer risks of SSRIs use (≧28 DDD group, adjusted OR = 0.87; 95% CI = 0.78-0.96). Sensitive analysis showed SSRIs, TCAs, and SNRIs did not increase gastric cancer risks significantly even in the group with peptic ulcer history.

CONCLUSIONS

An association between antidepressant exposure and gastric cancer was not apparent in this analysis.

Serotonin: a novel bone mass controller may have implications for alveolar bone

As recent studies highlight the importance of alternative mechanisms in the control of bone turnover, new therapeutic approaches can be envisaged for bone diseases and periodontitis-induced bone loss. Recently, it has been shown that Fluoxetine and Venlafaxine, serotonin re-uptake inhibitors commonly used as antidepressants, can positively or negatively affect bone loss in rat models of induced periodontitis. Serotonin is a neurotransmitter that can be found within specific nuclei of the central nervous system, but can also be produced in the gut and be sequestered inside platelet granules. Although it is known to be mainly involved in the control of mood, sleep, and intestinal physiology, recent evidence has pointed at far reaching effects on bone metabolism, as a mediator of the effects of Lrp5, a membrane receptor commonly associated with Wnt canonical signaling and osteoblast differentiation. Deletion of Lrp5 in mice lead to increased expression of Tryptophan Hydroxylase 1, the gut isoform of the enzyme required for serotonin synthesis, thus increasing serum levels of serotonin. Serotonin, in turn, could bind to HTR1B receptors on osteoblasts and stop their proliferation by activating PKA and CREB.

Although different groups have reported controversial results on the existence of an Lrp5-serotonin axis and the action of serotonin in bone remodeling, there is convincing evidence that serotonin modulators such as SSRIs can affect bone turnover. Consequently, the effects of this drug family on periodontal physiology should be thoroughly explored.

Bidirectional crosstalk between stress-induced gastric ulcer and depression under chronic stress

Stress contributes to a variety of diseases and disorders such as depression and peptic ulcer. The present study aimed to investigate the correlation between stress ulcer and depression in pathogenesis and treatment by using chronic stress depression (CSD), chronic psychological stress ulcer (CPSU) and water immersion restrain stress models in rats. Our data showed that the ulcer index of the animals after CSD exposure was significantly higher than that of controls. Depression-like behaviors were observed in rat after CPSU exposure. Fluoxetine hydrochloride significantly reduced the ulcer index of rats exposed to CPSU stress, while ranitidine inhibited depression-like behavior of the animals in CSD group. The ulcer index of rats administered with mifepristone after CPSU stress was markedly reduced compared to CPSU group, although there was no significant difference in the depression-like behavior between mifepristone-treated CSD group and naive controls. We also found that the rats exposed to CPSU or CSD stress displayed a lower level of corticosterone than naive controls, however, the acute stress (AS) group showed an opposite result. Additionally, in order to study the relevance of H(2) receptors and depression, we treated the CSD group with cimetidine and famotidine respectively. The data showed that cimetidine inhibited depression-like behavior in CSD rats, and famotidine had no impact on depression. Overall our data suggested that the hypothalamic-pituitary-adrenal (HPA) axis dysfunction may be the key role in triggering depression and stress ulcer. Acid-suppressing drugs and antidepressants could be used for treatment of depression and stress ulcer respectively. The occurrence of depression might be inhibited by blocking the central H(2) receptors.