Sub-chronic celecoxib prevents soluble beta amyloid-induced depressive-like behaviour in rats.

BACKGROUND: Depression and Alzheimer's disease (AD) are co-morbid conditions. Neuropsychiatric symptoms have been reported as prodromal symptoms of AD-like dementia and soluble forms of beta amyloid peptide (Aß), the main constituent of insoluble plaques typical of AD brains, have been implicated in such an effect. We have previously shown that intracerebral injection of Aß can evoke a depressive-like state in rats, accompanied by neurochemical and neuroendocrine alterations reminiscent of depressive symptoms in humans. AD and depression are crucially linked by neuroinflammation and cyclooxygenase II (COX-2) enzyme involvement is an intriguing field of research. Indeed, its pharmacological inhibition has shown both antidepressant and Aß modulating effects. METHODS: Male rats were exposed to sub-chronic celecoxib (15 mg/kg/day sc for 8 days), a selective COX-2 inhibitor or vehicle (saline), starting from the day before central intracerebroventricular injection of Aß peptide (5µL of 4 µM solution or vehicle for sham). Animals were tested for depressive-like behaviour by using the forced swimming test paradigm and prefrontal serotonin (5-HT) content and plasma Aß levels were further evaluated. RESULTS: We found that celecoxib treatment prevented the pro-depressive effects induced by Aß. Moreover, it also prevented the reduction in 5-HT content in prefrontal cortex of Aß-treated rats and decreased their plasma Aß levels. CONCLUSIONS: Taken together, our data indicate that celecoxib could be a suitable pharmaceutical tool for the treatment of depressive state related to increased Aß levels.

N-3 PUFA diet enrichment prevents amyloid beta-induced depressive-like phenotype.

Among neuropsychiatric diseases, depression is one of the most prevalent. Many pathologies have been indicated as comorbid with depression and in particular, neurodegenerative disorders such as Alzheimer's diseases (AD). In this regard, several evidences endorse a strong relationship between depression and AD, so much that this mental illness has been proposed either as a risk factor for AD or as a prodromic AD phase. Furthermore, amyloid beta (Aß) peptide, the main constituent of amyloid plaques commonly considered the principal hallmark of AD brains, has been shown to be increased, in its soluble form, in depressed patients. Accordingly, we have previously found that Aß, intracerebroventricularly (i.c.v.) injected, is able to evoke a depressive-like profile in rats accompanied by low cortical serotonin and reduced neurotrophin content. Taking into account the great increase in AD and depression prevalence, many environmental factors have been under study, particularly dietary factors, and the role of polyunsaturated fatty acids (PUFA) is becoming central in this field of research. Thus, aim of the present study was to evaluate the neurobehavioral effects of lifelong exposure to either n-3 PUFA rich or n-3 PUFA poor diet after Aß central administration. Results showed that n-3 PUFA enriched diet prevented the Aß- induced depressive-like behaviors, as reveled by the reduction in the immobility time in the FST test. Furthermore, n-3 PUFA rich diet exposure reverted also serotonin and neurotrophin level reduction in prefrontal cortex of Aß treated rats. Taken together, our data support the concept that supplementation of diet with n-3 PUFA represents a valid approach to reduce the risk of developing depressive symptoms, as well as reducing the risk of Aß-related pathologies, such as AD.

The NADPH oxidase NOX2 as a novel biomarker for suicidality: evidence from human post mortem brain samples.

Recent evidence points towards a role of oxidative stress in suicidality. However, few studies were carried out on the sources of reactive oxygen species (ROS) in subjects with suicidal behaviour. We have previously demonstrated that the NADPH oxidase NOX2-derived oxidative stress has a major role in the development of neuropathological alterations observed in an animal model of psychosis. Here, we investigated the possible increase in NOX2 in post mortem brain samples of subjects who died by asphyctic suicide (AS) compared with controls (CTRL) and subjects who died by non-suicidal asphyxia (NSA). We found that NOX2 expression was significantly higher in the cortex of AS subjects than in the other two experimental groups. NOX2 immunostaining was mainly detected in GABAergic neurons, with a minor presence of NOX2-positive-stained cells in glutamatergic and dopaminergic neurons, as well as astrocytes and microglia. A sustained increase in the expression of 8-hydroxy-2'-deoxyguanosine, an indirect marker of oxidative stress, was also detected in the cortex of AS subjects, compared with CTRL and NSA subjects. A significant elevation in cortical interleukin-6 immunoreactivity in AS subjects suggested an involvement of cytokine-associated molecular pathways in NOX2 elevations. Our results suggest that the increase in NOX2-derived oxidative stress in the brain might be involved in the neuropathological pathways leading to suicidal behaviour. These results may open innovative insights in the identification of new pathogenetic and necroscopic biomarkers, predictive for suicidality and potentially useful for suicide prevention.

Activation of PPAR gamma receptors reduces levodopa-induced dyskinesias in 6-OHDA-lesioned rats.

Long-term administration of l-3,4-dihydroxyphenylalanine (levodopa), the mainstay treatment for Parkinson's disease (PD), is accompanied by fluctuations in its duration of action and motor complications (dyskinesia) that dramatically affect the quality of life of patients. Levodopa-induced dyskinesias (LID) can be modeled in rats with unilateral 6-OHDA lesions via chronic administration of levodopa, which causes increasingly severe axial, limb, and orofacial abnormal involuntary movements (AIMs) over time. In previous studies, we showed that the direct activation of CB1 cannabinoid receptors alleviated rat AIMs. Interestingly, elevation of the endocannabinoid anandamide by URB597 (URB), an inhibitor of endocannabinoid catabolism, produced an anti-dyskinetic response that was only partially mediated via CB1 receptors and required the concomitant blockade of transient receptor potential vanilloid type-1 (TRPV1) channels by capsazepine (CPZ) (Morgese et al., 2007). In this study, we showed that the stimulation of peroxisome proliferator-activated receptors (PPAR), a family of transcription factors activated by anandamide, contributes to the anti-dyskinetic effects of URB+CPZ, and that the direct activation of the PPARγ subtype by rosiglitazone (RGZ) alleviates levodopa-induced AIMs in 6-OHDA rats. AIM reduction was associated with an attenuation of levodopa-induced increase of dynorphin, zif-268, and of ERK phosphorylation in the denervated striatum. RGZ treatment did not decrease striatal levodopa and dopamine bioavailability, nor did it affect levodopa anti-parkinsonian activity. Collectively, these data indicate that PPARγ may represent a new pharmacological target for the treatment of LID.

Improvement of renal function in epidermolysis bullosa patients after gluten free diet: two cases.

Epidermolysis bullosa (EB) is a rare inherited genetic disease characterized by an abnormal response of the skin and mucosa to mechanical trauma. Dystrophic EB (DEB) is very often associated with many extra cutaneous complications. Those complications involve either epithelial associated tissues or other organs. In particular, several renal complications have been described for DEB in the recessive form, such as amyloidosis, post-infection glomerulonephritis, upper and lower urinary tract obstruction and IgA-Nephropathy (IgAN). In the cases reported below we have two patients diagnosed with DEB that showed compromised renal function and proteinuria. The switch of the normal diet toward a gluten free diet resulted beneficial for both patients, since renal function was rescued and proteinuria cured. Moreover, a general health status improvement was recognised, given that nutritional condition was ameliorated and bone growing enhanced. Furthermore, in both patients the presence of autoantibodies anti-COL7 indicating an autoimmune form of the disease. Therefore, patients received low doses of betametasone useful to reduce inflammatory state and to control immune system function. In conclusion, our results prompt us to hypothesized that in these patients, due to the fragility of the intestinal mucosa, the absence in the diet of gluten may be beneficial.

Extraction, characterization and in vivo neuromodulatory activity of phytosterols from microalga Dunaliella tertiolecta.

In recent years, a great deal of research has been devoted to identify new natural sources of phytosterols and to improve methods for their recovery and purification. In this regard, unexplored natural sources of bioactive ingredients are gaining much attention since they can lead to the isolation of new compounds or bioactivities. The field of available natural sources has been further increased by including algae and, even more interestingly, microalgae. In the present study, a multidisciplinary approach has been used considering, in an integrated view, extraction, chemical composition and bioactivity of phytosterols from the microalga Dunaliella tertiolecta. A novel methodology to extract, separate and characterize microalgal-derived phytosterols has been developed. In addition, recoverable and reusable eluents have been selected in order to reduce the quantities of employed organic solvents. Finally, we addressed the question whether orally administered phytosterols reach the brain and if those interfere with the major neurotransmitter systems, such as the dopaminergic, serotoninergic and noradrenergic ones, in several brain areas of rats. Flash Liquid Chromatography has been used to separate the Total Sterol (TS) fraction, composed of twelve sterols, with a purity of 97.87% and a recovery percentage of 98%, while the "flash version" of Silver Ion Liquid Chromatography has been used to purify the most abundant phytosterols in TS, (22E,24R)- methylcholesta-5,7,22-trien-3ß-ol (ergosterol) and (22E,24R)-ethylcholesta-5,7,22-trien-3ß-ol (7-dehydroporiferasterol), with a purity of 97.4%. These two combined methods did not need sophisticated technologies but only cheap laboratory supplies. Moreover, the possibility of recovering and recycling the solvents used as eluents made it a cleaner process. Finally, for the first time, a neuromodulatory action of Dunaliella tertiolecta-derived phytosterols has been found in selective brain areas of rats.

Estrous cycle affects the neurochemical and neurobehavioral profile of carvacrol-treated female rats.

Carvacrol is the major constituent of essential oils from aromatic plants. It showed antimicrobial, anticancer and antioxidant properties. Although it was approved for food use and included in the chemical flavorings list, no indication on its safety has been estimated. Since the use of plant extracts is relatively high among women, aim of this study was to evaluate carvacrol effects on female physiology and endocrine profiles by using female rats in proestrus and diestrus phases. Serotonin and metabolite tissue content in prefrontal cortex and nucleus accumbens, after carvacrol administration (0.15 and 0.45g/kg p.o.), was measured. Drug effects in behavioral tests for alterations in motor activity, depression, anxiety-related behaviors and endocrine alterations were also investigated. While in proestrus carvacrol reduced serotonin and metabolite levels in both brain areas, no effects were observed in diestrus phase. Only in proestrus phase, carvacrol induced a depressive-like behavior in forced swimming test, without accompanying changes in ambulation. The improvement of performance in FST after subchronic treatment with fluoxetine (20mg/kg) suggested a specific involvement of serotonergic system. No differences were found across the groups with regard to self-grooming behavior. Moreover, in proestrus phase, carvacrol reduced only estradiol levels without binding hypothalamic estradiol receptors. Our study showed an estrous-stage specific effect of carvacrol on depressive behaviors and endocrine parameters, involving serotonergic system. Given the wide carvacrol use not only as feed additive, but also as cosmetic essence and herbal remedy, our results suggest that an accurate investigation on the effects of its chronic exposure is warranted.

Soluble beta amyloid(1-42): a critical player in producing behavioural and biochemical changes evoking depressive-related state?

BACKGROUND AND PURPOSE: Depression is common in early phases of Alzheimer's disease (AD) and may represent prodromal symptoms of dementia. Recent reports suggest that early memory deficits and neuropsychiatric symptoms are caused by soluble rather than aggregated betaamyloid (Abeta). Thus, we investigated the effects of soluble Abeta(1-42) on working memory and depressive/anxiety-related behaviour in rats and on 5-hydroxytryptaminergic neurotransmission and neurotrophin content in various brain regions. EXPERIMENTAL APPROACH: Behavioural reactivity to novel object recognition, open field, elevated plus maze and forced swimming test were assessed 7 days after i.c.v. injection of Abeta(1-42) or its vehicle. BDNF (brain-derived neurotrophic factor) and NGF (nerve growth factor) mRNA and protein levels and 5-hydroxytriptamine (5-HT) content were measured in the prefrontal cortex (PFC), striatum (STR) and nucleus accumbens (NAc). KEY RESULTS: Abeta(1-42) did not affect the ability to distinguish between familiar and novel objects, but Abeta-treated rats exhibited an increase in forced swimming immobility. No differences were revealed between experimental groups in the elevated plus maze test or in self-grooming (evaluated in the open field). In the PFC, but not STR or NAc, Abeta-injected rats exhibited a selective reduction in 5-HT content, BDNF and NGF expression. CONCLUSIONS AND IMPLICATIONS: Our data suggest that soluble Abeta-treated rats have a depressive, but not anxiogenic-like, profile, accompanied by brain region-dependent alterations in the expression of neurotrophins and 5-hydroxytryptaminergic neurotransmission. Hence, these alterations induced by soluble Abeta might be sensitive indicators of early phases of AD and possible risk factors for the expression of neuropsychiatric symptoms in AD.

Neurochemical changes in the striatum of dyskinetic rats after administration of the cannabinoid agonist WIN55,212-2.

Chronic use of levodopa, the most effective treatment for Parkinson's disease, causes abnormal involuntary movements named dyskinesias, which are linked to maladaptive changes in plasticity and disturbances of dopamine and glutamate neurotransmission in the basal ganglia. Dyskinesias can be modeled in rats with unilateral 6-hydroxydopamine lesions by repeated administration of low doses of levodopa (6 mg/kg, s.c.). Previous studies from our lab showed that sub-chronic treatment with the cannabinoid agonist WIN55,212-2 attenuates levodopa-induced dyskinesias at doses that do not interfere with physiological motor function. To investigate the neurochemical changes underlying WIN55,212-2 anti-dyskinetic effects, we used in vivo microdialysis to monitor extracellular dopamine and glutamate in the dorsal striatum of both the hemispheres of freely moving 6-hydroxydopamine-treated, SHAM-operated and intact rats receiving levodopa acutely or chronically (11 days), and studied how sub-chronic WIN55,212-2 (1 injection x 3 days, 20 min before levodopa) affected these neurochemical outputs. Our data indicate that: (1) the 6-hydroxydopamine lesion decreases dopamine turnover in the denervated striatum; (2) levodopa injection reduces extracellular glutamate in the side ipsilateral to the lesion of dyskinetic rats; (3) sub-chronic WIN55,212-2 prevents levodopa-induced glutamate volume transmission unbalances across the two hemispheres; and (4) levodopa-induced dyskinesias are inversely correlated with glutamate levels in the denervated striatum. These data indicate that the anti-dyskinetic properties of WIN55,212-2 are accompanied by changes of dopamine and glutamate outputs in the two brain hemispheres of 6-hydroxydopamine-treated rats.

Antidepressant-like activity and modulation of brain monoaminergic transmission by blockade of anandamide hydrolysis.

Although anecdotal reports suggest that cannabis may be used to alleviate symptoms of depression, the psychotropic effects and abuse liability of this drug prevent its therapeutic application. The active constituent of cannabis, delta9-tetrahydrocannabinol, acts by binding to brain CB1 cannabinoid receptors, but an alternative approach might be to develop agents that amplify the actions of endogenous cannabinoids by blocking their deactivation. Here, we show that URB597, a selective inhibitor of the enzyme fatty-acid amide hydrolase, which catalyzes the intracellular hydrolysis of the endocannabinoid anandamide, exerts potent antidepressant-like effects in the mouse tail-suspension test and the rat forced-swim test. Moreover, URB597 increases firing activity of serotonergic neurons in the dorsal raphe nucleus and noradrenergic neurons in the nucleus locus ceruleus. These actions are prevented by the CB1 antagonist rimonabant, are accompanied by increased brain anandamide levels, and are maintained upon repeated URB597 administration. Unlike direct CB1 agonists, URB597 does not exert rewarding effects in the conditioned place preference test or produce generalization to the discriminative effects of delta9-tetrahydrocannabinol in rats. The findings support a role for anandamide in mood regulation and point to fatty-acid amide hydrolase as a previously uncharacterized target for antidepressant drugs.