5-hydroxytryptamine actions in adipocytes: involvement of monoamine oxidase-dependent oxidation and subsequent PPARγ activation

Antidepressant- and Anxiolytic-like Effects of Pomegranate: Is It Acting by Common or Well-Known Mechanisms of Action?

The pharmacological effects of pomegranates have been described considering metabolic aspects such as hypoglycemic and hypolipidemic activities. The pomegranate extract has activity on the central nervous system (CNS) as a natural antidepressant and anxiolytic. The chemical composition of pomegranates is complex since the bioactive compounds are multiple secondary metabolites that have been identified in the extracts derived from the peel, seed, flowers, leaves, or in their combination; so, it has not been easy to identify an individual compound as responsible for its observed pharmacological properties. From this point of view, the present review analyzes the effects of crude extracts or fractions of pomegranates and their possible mechanisms of action concerning antidepressant- and anxiolytic-like effects in animal models. Serotonin receptors, estrogen receptors, the peroxisome proliferator-activated receptor gamma (PPARγ), or monoamine oxidase enzymes, as well as potent antioxidant and neuroplasticity properties, have been described as possible mediators involved in the antidepressant- and anxiolytic-like behaviors after pomegranate treatment. The pharmacological effects observed on the CNS in experimental models associated with a specific stress level suggest that pomegranates could simultaneously modulate the stress response by activating several targets. For the present review, scientific evidence was gathered to integrate it and suggest a possible pathway for mediators to be involved in the mechanisms of action of the pomegranate's antidepressant- and anxiolytic-like effects. Furthermore, the potential benefits are discussed on comorbid conditions with anxiety and depression, such as perimenopause transition and pain.

Upregulation of MAOA in the hippocampus results in delayed depressive-like behaviors in burn mice

OBJECTIVE

To observe depressive-like behavior and hippocampus monoamine oxidase A (MAOA) changes in burned mice.

METHODS

We tested depression and anxiety like behaviors of burn C57 mice with the sucrose preference test, forced swimming test (FST), open field test and elevated plus maze test and then detected the MAOA content and MAOA gene transcriptional levels in the hippocampus with western blot analysis and real-time quantitative PCR analysis. We then sought to reverse depressive-like behavior of burned mice with an MAOA inhibitor.

RESULTS

(1) Mice showed depressive and anxiety like behaviors one week after they were burned; (2) The content of MAOA in the hippocampus of burned mice was significantly higher than that in control mice (P<0.05); (3) MAOA gene transcription in the hippocampus of burned mice was significantly increased (MAOA mRNA was increased, P<0.05); (4) treatment with a MAOA inhibitor (phenelzine) significantly increased the sucrose preference rate and decreased FST immobility time in burned mice, and also decreased elevated expression of MAOA in the hippocampus of burned mice.

CONCLUSION

Burned mice showed "delayed" depressive-like behavior combined with a degree of anxiety; this phenomenon is likely associated with the increase in MAOA expression in the hippocampus.

Characterizing the dynamics of the rumen microbiota, its metabolites, and blood metabolites across reproductive stages in Small-tailed Han sheep

IMPORTANCE

Our study illustrates the succession of the rumen microbiota and its metabolites in Small-tailed Han sheep at different reproductive stages. Among them, Firmicutes and Prevotella, which are related to energy metabolism, increased in abundance during pregnancy, while Fibrobacter, a fiber-degrading bacterium, increased in abundance during lactation. At the same time, the microbial metabolic profile and serum metabolic profile characteristics of different reproductive stages were revealed, and some functional pathways and metabolites related to energy and immunity were found. This study provides a reference for the health management of ruminants during non-pregnancy, pregnancy, and lactation.

Chronic fluoxetine treatment induces lipid accumulation but does not alter the expression of Pref-1 in rat adipose tissue

This study aims to investigate the effects of chronic fluoxetine (FLX) treatment on preadipocyte factor-1 (Pref-1) expression in subcutaneous, visceral and brown adipose tissues, and on the size of vacuoles in a dipocytes obtained from the perirenal regions in rats. Twenty-eight Wistar rats were treated with FLX at two different doses and fourteen animals received vehicle. After 40 days of treatment, the subcutaneous, perirenal and interscapular adipose tissues were collected. Pref-1 expression was examined using an immunohistochemical method and the vacuolar area was measured in stained sections. In the low dose FLX group, the size of vacuoles increased both in male and female animals. The high dose of FLX also induced a significant increase of vacuole size, but only in male animals. Neither of the two doses of FLX has significantly affected the Pref-1 expression in any type of adipose tissue.

Pioglitazone could induce remission in major depression: a meta-analysis

BACKGROUND

Pioglitazone, a selective agonist of the nuclear transcription factor peroxisome proliferator-activated receptor-gamma (PPAR-γ), prescribed for the treatment of type 2 diabetes, could have antidepressant properties. However, its potential to induce remission of major depressive episodes, the optimal clinical target for an antidepressant drug, is a matter of concern. Indeed, only one out of four double-blind randomized controlled trials show higher remission rates with pioglitazone than with control treatments. Hence, the main aim of this study was to perform a meta-analysis of the efficacy of pioglitazone for the treatment of MDE, focusing on remission rates.

METHODS

Four double-blind randomized controlled trials, comprising 161 patients with an MDE, were included in this meta-analysis. Pioglitazone was studied either alone (one study) or as add-on therapy to conventional treatments (antidepressant drugs or lithium salts). It was compared either to placebo (three studies) or to metformin (one study). Remission was defined by a Hamilton Depression Rating Scale score <8 after treatment.

RESULTS

Pioglitazone could induce higher remission rates than control treatments (27% versus 10%, I²=17.3%, fixed-effect model: odds ratio [OR] =3.3, 95% confidence interval [95% CI; 1.4; 7.8], P=0.008). The OR was even higher in the subgroup of patients with major depressive disorder (n=80; 23% versus 8%, I²=0.0%; fixed-effect model: OR =5.9, 95% CI [1.6; 22.4], P=0.009) and in the subgroup of patients without metabolic comorbidities (n=84; 33% versus 10%, I²=0.0%; fixed-effect model: OR =5.1, 95% CI [1.5; 17.9], P=0.01). As compared to control treatments, results suggest six patients would need to be treated with pioglitazone in order to achieve the possibility of one more remission.

CONCLUSION

Pioglitazone, either alone or as add-on therapy to conventional treatments, could induce remission of MDE, suggesting that drugs with PPAR-γ agonist properties may be true and clinically relevant antidepressants, even in patients without metabolic comorbidities.

PPARγ upregulation induced by vagus nerve stimulation exerts anti-inflammatory effect in cerebral ischemia/reperfusion rats

Background

It is well known that peroxisome proliferator-activated receptor gamma (PPARγ), a ligand-activated transcription factor, plays a protective role in anti-inflammatory responses in both acute and chronic central nerve system (CNS) insults. Emerging evidence in rats suggests that vagus nerve stimulation (VNS), while restraining inflammatory cytokine production in the peripheral nervous system, also exerts a significant CNS neuroprotective function against ischemic stroke injury. The aim of this study was to explore the role of PPARγ in VNS-mediated anti-inflammatory protection against ischemic stroke damage.

Material/Methods

Adult male Sprague-Dawley rats (total n=160) preconditioned through transfection with either PPARγ small interfering RNA (siRNA) or lentiviral vector without siRNA and surgically subjected to middle cerebral artery occlusion and reperfusion subsequently received VNS treatment at 30 min post-occlusion. The expression of PPARγ after VNS treatment was measured by real-time PCR and Western blotting, also supported by immunofluorescence staining. Subsequently, the neurological deficits scores, the infarct volume, and the brain histopathology were all evaluated. Additionally, the influence on the pro-inflammatory cytokines expression and neuro-immune cells activation was determined by ELISA and immunofluorescence staining.

Results

We found that VNS upregulated expression of PPARγ in ischemia penumbra, diminished the extent of ischemic infarct, alleviated neuronal injury, and suppressed pro-inflammatory cytokine expression and immune cell activation (P<0.05). However, rats with PPARγ silencing failed to manifest significant neuroprotection and anti-inflammatory effect induced by VNS treatment (p>0.05).

Conclusions

PPARγ may participate in the process by which VNS modulates the neuro-inflammatory response following ischemia/reperfusion in rats.