Metabolomics Fingerprint Induced by the Intranigral Inoculation of Exogenous Human Alpha-Synuclein Oligomers in a Rat Model of Parkinson's Disease.

Parkinson's disease (PD) is considered a synucleinopathy because of the intraneuronal accumulation of aggregated α-synuclein (αSyn). Recent evidence points to soluble αSyn-oligomers (αSynO) as the main cytotoxic species responsible for cell death. Given the pivotal role of αSyn in PD, αSyn-based models are crucial for the investigation of toxic mechanisms and the identification of new therapeutic targets in PD. By using a metabolomics approach, we evaluated the metabolic profile of brain and serum samples of rats infused unilaterally with preformed human αSynOs (HαSynOs), or vehicle, into the substantia nigra pars compacta (SNpc). Three months postinfusion, the striatum was dissected for striatal dopamine (DA) measurements via High Pressure Liquid Chromatography (HPLC) analysis and mesencephalon and serum samples were collected for the evaluation of metabolite content via gas chromatography mass spectrometry analysis. Multivariate, univariate and correlation statistics were applied. A 40% decrease of DA content was measured in the HαSynO-infused striatum as compared to the contralateral and the vehicle-infused striata. Decreased levels of dehydroascorbic acid, myo-inositol, and glycine, and increased levels of threonine, were found in the mesencephalon, while increased contents of fructose and mannose, and a decrease in glycine and urea, were found in the serum of HαSynO-infused rats. The significant correlation between DA and metabolite content indicated that metabolic variations reflected the nigrostriatal degeneration. Collectively, the metabolomic fingerprint of HαSynO-infused rats points to an increase of oxidative stress markers, in line with PD neuropathology, and provides hints for potential biomarkers of PD

Chronic treatment with hormonal contraceptives alters hippocampal BDNF and histone H3 post-translational modifications but not learning and memory in female rats

Hormonal contraceptives prevent ovulation with subsequent reduction in endogenous levels of estradiol, progesterone and its neuroactive metabolite allopregnanolone. These neurosteroids modulate several brain functions, including neuronal plasticity, cognition and memory. We hypothesized that hormonal contraceptives might affect synaptic plasticity, learning and memory, as a consequence of suppressed endogenous hormones levels. Female rats were orally treated with a combination of ethinyl estradiol (EE, 0.020 mg) and levonorgestrel (LNG, 0.060 mg) once daily for four weeks. Decreased hippocampal brain-derived neurotrophic factor (BDNF) levels and altered histone H3 post-translational modifications (PTMs) were observed 14 days after discontinuation from chronic EE-LNG treatment. These effects were not accompanied by alterations in long-term plasticity at glutamatergic synapses, recognition memory in the novel object and novel place location tests, or spatial learning, memory, and behavioral flexibility in the Morris water maze test. Thus, decreased BDNF content does not affect synaptic plasticity and cognitive performance; rather it might be relevant for the occurrence of certain psychiatric symptoms, reported by some women using hormonal contraceptives. These results provide the first evidence of hippocampal epigenetic changes induced by hormonal contraceptives and complement previous studies on the neurobiological actions of hormonal contraceptives; the finding that effects of chronic EE-LNG treatment on BDNF content and histone PTMs are observed 14 days after drug discontinuation warrants further investigation to better understand the implications of such long-term consequences for women's health

Neuroplastic changes in c-Fos, ΔFosB, BDNF, trkB, and Arc expression in the hippocampus of male Roman rats: differential effects of sexual activity

Sexual activity causes differential changes in the expression of markers of neural activation (c-Fos and Delta FosB) and neural plasticity (Arc and BDNF/trkB), as determined either by Western Blot (BDNF, trkB, Arc, and Delta FosB) or immunohistochemistry (BDNF, trkB, Arc, and c-Fos), in the hippocam pus of male Roman high (RHA) and low avoidance (RLA) rats, two psychogenetically selected rat lines that display marked differences in sexual behavior (RHA rats exhibit higher sexual motivation and better copulatory performance than RLA rats). Both methods showed (with some differences) that sexual activity modifies the expression levels of these markers in the hippocampus of Roman rats depending on: (i) the level of sexual experience, that is, changes were usually more evident in sexually naive than in experienced rats; (ii) the hippocampal partition, that is, BDNF and Arc increased in the dorsal but tended to decrease in the ventral hippocampus; (iii) the marker considered, that is, in sexually experienced animals BDNF, c-Fos, and Arc levels were similar to those of controls, while Delta FosB levels increased; and (iv) the rat line, that is, changes were usually larger in RHA than RLA rats. These findings resemble those of early studies in RHA and RLA rats showing that sexual activity influences the expression of these markers in the nucleus accumbens, medial prefrontal cortex, and ventral tegmental area, and show for the first time that also in the hippocampus sexual activity induces neural activation and plasticity, events that occur mainly during the first phase of the acquisition of sexual experience and depend on the genotypic/phenotypic characteristics of the animals

Immunochemical detection of BDNF in the brain of a rat model of depression

Several lines of evidence show a relationship between alterations in the mechanisms that control the expression of neurotrophic factors and mood disorders (1). In particular, support for the role of brain-derived neurotrophic factor (BDNF) in the pathogenesis of depression and related deficits in neuronal plasticity comes from evidence that a reduction of BDNF expression has been found in postmortem brains and serum of depressed subjects and that the BDNF gene is required for the response to antidepressant drugs. With the aim to contribute to the characterization of the molecular and neuronal systems involved in the pathogenesis of depression and in the mechanism of action of the antidepressant treatments, here we use the outbread Roman High- (RHA) and Roman Low-Avoidance (RLA) rat lines, psychogenetically selected for rapid versus poor acquisition of active avoidance, respectively, and bearing several behavioral characteristics closely resembling the cardinal symptoms of depression (2), to investigate on the immunochemical occurrence of BDNF in selected areas of the RHA and RLA rat brain by means of western blot (WB) and immunohistochemistry. WB analysis indicates that the relative levels of BDNF patently and markedly differed in the hippocampus, where they were significantly lower by 58% in RLA vs RHA rats (p = 0.0014). In the remaining examined areas, namely the prefrontal cortex, the caudate-putamen complex proper, the core and shell regions of the nucleus accumbens and the ventral tegmental area, the relative BDNF levels did not show statistically significant differences. In tissue sections, BDNF-like immunoreactive (LI) material labelled neuronal cell bodies, proximal processes and varicose nerve fibers, with an uneven distribution in telencephalic cerebral cortex, hippocampus, amygdala, nucleus accumbens, caudate-putamen complex proper, thalamus and ventral tegmentum of the midbrain. Densitometric analysis of immunostained brain sections were used to quantify differences among the two rat lines. The results obtained provide a morphological evidence for a differential expression of BDNF in specific areas of RLA vs RHA rat brains and may form the morphological basis to understand the regulation of the trophic machinery in depression

Effect of acute administration of Pistacia lentiscus L. essential oil on rat cerebral cortex following transient bilateral common carotid artery occlusion

<p>Abstract</p> <p>Background</p> <p>Ischemia/reperfusion leads to inflammation and oxidative stress which damages membrane highly polyunsaturated fatty acids (HPUFAs) and eventually induces neuronal death. This study evaluates the effect of the administration of <it>Pistacia lentiscus </it>L. essential oil (E.O.), a mixture of terpenes and sesquiterpenes, on modifications of fatty acid profile and endocannabinoid (eCB) congener concentrations induced by transient bilateral common carotid artery occlusion (BCCAO) in the rat frontal cortex and plasma.</p> <p>Methods</p> <p>Adult Wistar rats underwent BCCAO for 20 min followed by 30 min reperfusion (BCCAO/R). 6 hours before surgery, rats, randomly assigned to four groups, were gavaged either with E.O. (200 mg/0.45 ml of sunflower oil as vehicle) or with the vehicle alone.</p> <p>Results</p> <p>BCCAO/R triggered in frontal cortex a decrease of docosahexaenoic acid (DHA), the membrane highly polyunsaturated fatty acid most susceptible to oxidation. Pre-treatment with E.O. prevented this change and led further to decreased levels of the enzyme cyclooxygenase-2 (COX-2), as assessed by Western Blot. In plasma, only after BCCAO/R, E.O. administration increased both the ratio of DHA-to-its precursor, eicosapentaenoic acid (EPA), and levels of palmytoylethanolamide (PEA) and oleoylethanolamide (OEA).</p> <p>Conclusions</p> <p>Acute treatment with E.O. before BCCAO/R elicits changes both in the frontal cortex, where the BCCAO/R-induced decrease of DHA is apparently prevented and COX-2 expression decreases, and in plasma, where PEA and OEA levels and DHA biosynthesis increase. It is suggested that the increase of PEA and OEA plasma levels may induce DHA biosynthesis via peroxisome proliferator-activated receptor (PPAR) alpha activation, protecting brain tissue from ischemia/reperfusion injury.</p

Immunochemical detection of trkB receptor in the brain of a rat model of depression

The outbread Roman High- (RHA) and Roman Low-Avoidance (RLA) rat lines were psychogenetically selected for rapid versus poor acquisition of active avoidance, respectively, and differ in many behavioural traits that closely resemble the cardinal symptoms of depression (1). Beyond the monoamine hypothesis of depression, compelling evidence suggests that mood disorders are characterized by reduced neuronal plasticity. Consistently, it has been shown that exposure to stress and antidepressant treatment modulate the expression of neurotrophic molecules and their relevant receptors, and that these changes show an anatomical specificity (2). With the aim to characterize the molecular and neuronal systems involved in the pathogenesis of depression and in the mechanism of action of the antidepressant treatments, here we investigate on the immunochemical occurrence of trkB, the high affinity tyrosinekinase receptor for brain-derived neurotrophic factor (BDNF), in selected areas of the RHA and RLA rat brain by means of western blot (WB) and immunohistochemistry. WB analysis indicates that the relative levels of trkB patently and markedly differed in the prefrontal cortex and the hippocampus, where they were lower in RLA vs RHA rats, and in the caudate-putamen complex proper where, by contrast, they were higher in RLA vs RHA rats. No statistically significant differences were seen in nucleus accumbens and ventral tegmental area. In tissue sections, trkB-like immunoreactive (LI) labelling was mainly localized to neuronal cell bodies and proximal processes, unevenly distributed in the telencephalic cerebral cortex, the hippocampus, and the ventral tegmentum of the midbrain. Densitometric analysis of immunostained brain sections revealed that differences among the two groups are consistent to a good extent with WB data. As a whole, the finding of a different expression of trkB receptor in the RLA vs RHA rat brains implies the occurrence of an altered neuronal responsiveness to BDNF in specific brain regions and may contribute to outline the molecular and morphological basis for the distinct vulnerability to depression in the two rat lines

BDNF, trkB and PSA-NCAM in the hippocampus of Roman rats after forced swimming

The selective breeding of Roman High- (RHA) and Low-Avoidance (RLA) rats are considered as a genetic model of resilience to stress-induced depression and of vulnerability to that trait, respectively1. There is evidence that alterations in neuronal plasticity in the hippocampus and other brain areas are critically involved in the pathophysiology of mood disorders. Here, we investigated on immunochemical occurrence of Brain-derived neurotrophic factor (BDNF), tyrosine-kinase receptor trkB and polysialilated form of the neural cell adhesion molecule (PSANCAM) in the hippocampus of the Roman rat lines under baseline conditions and after acute forced swimming (FS). Western blot (WB) analyses showed that, in basal conditions, the relative levels of BDNF, trkB and PSA-NCAM markedly differed, appearing lower by 48%, 25% and 65%, respectively, in RLA vs RHA rats. WB analyses carried out after FST showed no differences between baseline and FST rats. In tissue sections, BDNF-, trkB- and PSA-NCAM-like immunoreactivity (LI) showed a distinctive labelling, mainly localized to proximal neuronal processes and nerve fibers distributed in the Ammon’s horn and dentate gyrus (DG). A number of PSA-NCAM-positive neurons in the subgranular layer of dentate gyrus also occurred. Densitometric analysis further showed differences in the hippocampal subregions. Thus, upon FST, BDNF-LI was less abundant in the CA3 sector of the Ammon’s horn of FST vs control RLA rats (-24%), whereas PSA-NCAM-LI was more abundant in the DG of RHA than RLA rats (+26%). Our findings suggest that an altered neuronal availability of and/or responsiveness to BDNF and inadequate dynamic events related to neuroplasticity may contribute to outline the molecular and morphological basis for the distinct vulnerability to stress-induced depression in the two rat lines

Effect of resveratrol on plasmatic molecular indicators of brain tissue response to the hypoperfusion/ reperfusion challenge

It is well-documented that endocannabinoids (eCBs) and congeners show a neuroprotective role in several experimental models of brain injury and that changes in eCB levels in peripheral blood cells may reflect the severity of neurological insult. We have previously shown that the preventive administration of dietary natural compounds may increase the plasmatic levels of palmytoylethanolamide (PEA) and oleoylethanolamide (OEA) following the transient bilateral common carotid artery occlusion (BCCAO)-induced brain tissue challenge (1). Resveratrol (RVT), (3,4’, 5-trihidroxystilbene) is a strong natural antioxidant of polyphenolic structure found in grapes and red wine, with many physiological effects, including the prevention of lipid peroxidation in human LDL, inhibition of arachidonic acid metabolism, and platelet activity. RVT has been further shown to protect cerebral tissue and cardiac muscle from tissue damage caused by oxidative stress triggered by reperfusion (2) and has been proposed as a potential neuroprotective agent in treating acute states in focal cerebral ischemia injury (3). In this line, we intend to evaluate whether exogenous administration of RVT prior to induction of BCCAO followed by reperfusion influences the molecular changes occurring in cerebral cortex and plasma, with particular focus on the eCB system. With this aim, cerebral hypoperfusion was produced by a 30 min BCCAO followed by 60 min reperfusion (BCCAO/R). Animals were starved for 12 hours before surgery and 6 hours prior to ischemia RVT (40 mg/kg/0.45 ml of sunflower oil as vehicle) was administered via gavage. Biological samples of plasma, cerebrospinal fluid (CSF), and brain tissue were examined by HPLC, gel zymography, western blot and immunohistochemistry. Data obtained indicate that RVT appears to influence the outcome of BCCAO/R cerebral injury by modulating changes in levels of lipid hydroperoxides, markers of oxidative stress, eCBs and eCB congeners, expression of CB1 and CB2 receptors, peroxisome proliferator-activated receptor- (PPAR) alpha, ciclooxygenase-2 (COX-2) protein levels and enzymatic activity of matrix-metalloproteinase- 9 (MMP-9). Interestingly, changes in brain of some of these parameters, like lipid hydroperoxides, were also found in plasma. Results obtained suggest that exogenous administration of RVT may modulate the brain tissue compensatory or repair mechanisms triggered by the hypoperfusion/reperfusion and support the possible use of this molecule as treatment to prevent the BCCAO/R-induced brain insult. In addition, the finding that changes in plasma mirrored those found in cerebral tissue, opens to the possibility to test whether RSV exerts its positive activities in humans

Relationship between coronary plaque morphology of the left anterior descending artery and 12 months clinical outcome: the CLIMA study

Abstract Aims The CLIMA study, on the relationship between coronary plaque morphology of the left anterior descending artery and twelve months clinical outcome, was designed to explore the predictive value of multiple high-risk plaque features in the same coronary lesion [minimum lumen area (MLA), fibrous cap thickness (FCT), lipid arc circumferential extension, and presence of optical coherence tomography (OCT)-defined macrophages] as detected by OCT. Composite of cardiac death and target segment myocardial infarction was the primary clinical endpoint. Methods and results From January 2013 to December 2016, 1003 patients undergoing OCT evaluation of the untreated proximal left anterior descending coronary artery in the context of clinically indicated coronary angiogram were prospectively enrolled at 11 independent centres (clinicaltrial.gov identifier NCT02883088). At 1-year, the primary clinical endpoint was observed in 37 patients (3.7%). In a total of 1776 lipid plaques, presence of MLA 180° (HR 2.4, 95% CI 1.2–4.8), and OCT-defined macrophages (HR 2.7, 95% CI 1.2–6.1) were all associated with increased risk of the primary endpoint. The pre-specified combination of plaque features (simultaneous presence of the four OCT criteria in the same plaque) was observed in 18.9% of patients experiencing the primary endpoint and was an independent predictor of events (HR 7.54, 95% CI 3.1–18.6). Conclusion The simultaneous presence of four high-risk OCT plaque features was found to be associated with a higher risk of major coronary events