Pharmacological and nutritional control of dysbiosis related to CNS disorders: gut-brain axis

'Leaky gut' syndrome has attracted much attention in recent years, and represents now a complementary/alternative target for several complex diseases characterized by this pathological condition. It is often described as an increase in the permeability of the intestinal mucosa, allowing bacteria, toxic digestive metabolites, bacterial toxins, and small detrimental molecules to 'leak' into the bloodstream. The microbiota-gut is an integral component of the gut–brain neuroendocrine metabolic axis and any microbiota-gut disruption that can occur, could distressed homeostasis and share an inflammatory response, affecting distal organs including the brain. It has been shown, indeed, that the gut can influence the blood brain barrier (BBB) through gastrointestinal-derived hormones, small molecule and metabolic co-factor production, or through cytokine synthesis and other inflammatory mechanisms. Therefore, the CNS is under constant attack or, conversely, advantage from a wide variety of neuro-psychotropic-modulating microbes, and their metabolites. So, the proper neurodevelopment and functioning of the CNS depends from an integrated, rather than opposing, cross-talk between gut-gut microbiota and brain. Several CNS disturbances were related to gastrointestinal dysfunction and 'leaky brain', underlining the need of identifying new integrative and multi-targeted approaches. These complex diseases, being multifactorial, could result, in fact, less responsive to targeted standard drugs, since poorly fits ‘one-disease one-target’ and ‘one-target one-compound’ paradigms in this context. Here, we focused on autism spectrum disorders (ASDs) and major depressive disorder (MDD), two brain disorders linked to a dysfunction of BBB and impacted by immune and inflammatory peripheral stimuli. Our aim has been to evaluate the possible therapeutic potential of modulating several aspects of these multifactorial disorders, in order to benefit of peripheral and central contributions, converging on an improvement of overall health. To this aim we used BTBR T+tf/J (BTBR) mice model of ASDs and high fat diet-induced MDD in young mice, and the possible pharmacological modulation by palmitoylethanolamide (PEA) was investigated. PEA, is an endogenous N-acyl-ethanolamine, biosynthesized to maintain cellular homeostasis when this is challenged by external stressors provoking inflammation, neuronal damage and pain. The interaction and activation of PPARα has been recognized as the main mechanism of the effects evoked by this acylethanolamide. In particular, the analgesic and anti-inflammatory effects of PEA were demonstrated to be mediated by PPARα activation, since it has no effect in PPARα null mice. Indeed, the discovery of PPARα in distinct areas of the brain, opened a new scenario to explore the possible activity of this acylethanolamide in the CNS. Recently it has been demonstrated that genetic inactivation of PPARα, particularly abundant in the CNS, leads to a behavioral and cognitive phenotype reminiscent of that of preclinical models of ASDs, i.e. mouse model BTBR T+tf/J (BTBR), which displays an improved repetitive behavior when autistic mice are treated with a synthetic PPARα agonist. These results, not only indicated a central role for this receptor in neurological functions associated with the behavior, but more interestingly highlighted PPARα as a potential pharmacological target to lessen ASDs symptoms. On the other side PEA activity at intestinal level has suggested a possible role of this acylethanolamide in modulating not only gut function, such as intestinal transit and permeability, but also gut-brain axis. Before evaluating the effect of PEA on BTBR mice, in the first part of this PhD programme, we performed a study, also evaluating sex influence, on gut microbiota composition, behavioral features, and intestinal integrity, inflammatory status and architecture of adult male and female BTBR mice. These gender characterizations arise from the well-known different clinical features of male and female autistic patients and the need to identify them in a mouse model of ASD. Consistently with gut-brain axis hypothesis, we showed that BTBR mice presented a profound intestinal dysbiosis compared to control strain, more marked in female than in male mice, indicating Bacteroides, Parabacteroides, Sutterella, Dehalobacterium and Oscillospira genera as key drivers of sex-specific gut microbiota profiles associated with altered behavior. Interestingly, we also showed that the dysbiosis was accompanied in BTBR mice by increased gut permeability and colon inflammation. Therefore, we have considered BTBR mice, as an idiopathic model of autism useful to investigate not only the correction of the autistic behavior, but also a starting point to investigate whether the reduction of intestinal inflammation and integrity, and possibly the restoration of gut microbiota balance may ameliorate pathological traits. Based on this background, the aim of this study was to investigate the pharmacological effects of PEA on autistic-like behaviour of BTBR T+tf/J mice and to shed light on the contributing mechanisms. PEA was able to revert the altered behavior of autistic mice. This effect was contingent to PPARα activation, since was blunted by PPARα blocking or deletion. At mechanistic level, PEA restored hippocampal BDNF signaling, improved mitochondrial dysfunction and reduced serum, hippocampal and colonic inflammation. These beneficial effects were related to the reduction of leaky gut in PEA-treated BTBR mice mediated by increased expression of colonic tight junctions. In addition, PEA modulated gut microbiota composition, underlining the strong link between gut and brain. In last years, the connection between modification in gut microbiota induced by obesity and the development of MDD has become more evident. High fat feeding causes the production of several inflammatory mediators that can compromise colonic epithelial barrier function, with the translocation of bacterial metabolites in CNS, evoking deleterious events. The modulation of PPARα, mostly expressed in hippocampus, has demonstrated to improve synaptic dysfunction and HFD-related pathological events in MDD. Here, we have addressed the effects of PEA in a mouse model of HFD-induced depression, focusing on converging mechanisms involved in its activity. In particular, we assessed PEA capability in modulating the gut-brain axis and ameliorating depressive behavior. The treatment with PEA improved the depressive-like behavior and memory deficit, shown by HFD animals, impacting on BDNF signaling pathway and reducing neuroinflammation, both in hypothalamus, hippocampus and prefrontal cortex. These beneficial effects of PEA, as PPARα agonist, were correlated to an increased expression of PPARα, its coactivator PGC1α, and the downstream gene FGF21. As in BTBR model, here PEA also modulated gut microbiota composition, reducing the amount of endotoxin-producer Desulfovibrio and increasing Clostridiales genus relative abundance, and consistently Clostridiales-producing metabolites, including short-chain fatty acids. In conclusion, PEA, a multifunctional compound, can represent a novel therapeutic approach for multifactorial disorders, such as ASDs and MDD, able to counteract the alteration of central and peripheral pathways involved in their onset and progression

Palmitoylethanolamide modulates high-fat diet-shaped gut function and microbiota composition in obese mice

Introduction/Background & aims: Emerging data indicate a pivotal role for gut microbiota in the progression of obesity. Indeed, in the gut, high-fat diet (HFD) intake induces the loss of barrier integrity, causing the transfer of detrimental factors (i.e. lipopolysaccharide, LPS) into the systemic circulation, leading to metabolic dysfunctions and an overall state of low-grade inflammation, called “met- ainflammation” [1]. The metabolic and anti-inflammatory activities of palmitoylethanolamide (PEA), an endogenous lipid mediator, prompt us to evaluate its capability to improve intestinal homeostasis and shape gut microbiota composition altered in HFD-fed obese mice. Method/Summary of work: Male C57Bl/6 J mice received standard diet (STD) or HFD (n = 10 each group). After 12 weeks, a subgroup of HFD mice was treated with PEA (30 μg/kg/die per os) for 7 weeks. Body weight was monitored during the treatment and fat mass was evaluated at the end of experimental time. Systemic parameters and intestinal function were examined using ELISA assay, and Real-Time PCR analysis, respectively. Faecal microbiota was studied by per- forming 16S rDNA amplicon sequencing and linear discriminant analy- sis in order to obtain the operational taxonomic units (OTUs) defining the bacterial communities

nutraceuticals an integrative approach to starve parkinson s disease

Abstract The therapeutic approach of multifactorial complex diseases is always a challenge; Parkinson's disease (PD) is a heterogeneous neurodegenerative disorder triggered by genetic and environmental factors, contributing to its etiology. Indeed, several pathogenic mechanisms lead to selective dopaminergic neuronal injury, including oxidative stress, mitochondrial dysfunction, alteration of endoplasmic reticulum-to-Golgi protein trafficking, excitotoxicity, and neuroinflammation. Current treatment approaches include mainly dopamine replacement therapy or optimizing dopaminergic transmission; however, these strategies that do not counteract the pathogenic mechanisms underlying PD symptoms and often are less effective over time. Recently, there have been growing interest in the therapeutic use of nutraceuticals, that could represent an integrative approach to the pharmacological standard therapy and specifically affect one or more pathogenic pathways. The intake of nutraceuticals or nutritional modifications are generally safe and can be combined with current common drug therapy in most cases to improve the patient's quality of life and/or mitigate PD symptoms. The current review focuses on several key nutritional compounds and dietary modifications that are effective on several pathogenic pathways involved in PD onset and progression, and further highlights the rationale behind their potential use for the prevention and treatment of PD

Social isolation triggers oxidative status and impairs systemic and hepatic insulin sensitivity in normoglycemic rats

Drug-naïve psychotic patients show metabolic and hepatic dysfunctions. The rat social isolation model of psychosis allows to investigate mechanisms leading to these disturbances to which oxidative stress crucially contributes. Here, we investigated isolation-induced central and peripheral dysfunctions in glucose homeostasis and insulin sensitivity, along with redox dysregulation. Social isolation did not affect basal glycemic levels and the response to glucose and insulin loads in the glucose and insulin tolerance tests. However, HOMA-Index value were increased in isolated (ISO) rats. A hypothalamic reduction of AKT phosphorylation and a trend toward an increase in AMPK phosphorylation were observed following social isolation, accompanied by reduced GLUT-4 levels. Social isolation also induced a reduction of phosphorylation of the insulin receptor, of AKT and GLUT-2, and a decreased phosphorylation of AMPK in the liver. Furthermore, a significant reduction in hepatic CPT1 and PPAR-α levels was detected. ISO rats also showed significant elevations in hepatic ROS amount, lipid peroxidation and NOX4 expression, whereas no differences were detected in NOX2 and NOX1 levels. Expression of SOD2 in the mitochondrial fraction and SOD1 in the cytosolic fraction was not altered following social isolation, whereas SOD activity was increased. Furthermore, a decrease of hepatic CAT and GSH amount was observed in ISO rats compared to GRP animals. Our data suggest that the increased oxidant status and antioxidant capacity modifications may trigger hepatic and systemic insulin resistance, by altering signal hormone pathway and sustaining subsequent alteration of glucose homeostasis and metabolic impairment observed in the social isolation model of psychosis

Extracorporeal shock waves alone or combined with raloxifene promote bone formation and suppress resorption in ovariectomized rats

Osteoporosis is a metabolic skeletal disease characterized by an imbalance between osteoclast-mediated bone resorption and osteoblast-mediated bone formation. We examined the beneficial effect of shock waves (SW) alone or in combination with raloxifene (RAL) on bone loss in ovariectomized rats (OVX). Sixteen weeks after surgery, OVX were treated for five weeks with SW at the antero-lateral side of the right hind leg, one session weekly, at 3 Hz (EFD of 0.33 mJ/mm2), or with RAL (5 mg/kg/die, per os) or with SW+RAL. Sera, femurs, tibiae and vertebrae were sampled for following biochemical and histological analysis. SW, alone or combined with RAL, prevented femur weight reduction and the deterioration of trabecular microarchitecture both in femur and vertebrae. All treatments increased Speed of Sound (SoS) values, improving bone mineral density, altered by OVX. Serum parameters involved in bone remodeling (alkaline phosphatase, receptor activator of nuclear factor kappa-B ligand, osteoprotegerin) and osteoblast proliferation (PTH), altered by ovariectomy, were restored by SW and RAL alone or in combination. In tibiae, SW+RAL significantly reduced cathepsin k and TNF-α levels, indicating the inhibition of osteoclast activity, while all treatments significantly increased runt-related transcription factor 2 and bone morphogenetic-2 expression, suggesting an increase in osteoblastogenic activity. Finally, in bone marrow from tibiae, SW or RAL reduced PPARγ and adiponectin transcription, indicating a shift of mesenchymal cells toward osteoblastogenesis, without showing a synergistic effect. Our data indicate SW therapy, alone and in combination with raloxifene, as an innovative strategy to limit the hypoestrogenic bone loss, restoring the balance between bone formation and resorption

Palmitoylethanolamide counteracts autistic-like behaviours in BTBR T+tf/J mice: Contribution of central and peripheral mechanisms

Abstract Autism spectrum disorders (ASD) are a group of heterogeneous neurodevelopmental conditions characterized by impaired social interaction, and repetitive stereotyped behaviours. Interestingly, functional and inflammatory gastrointestinal diseases are often reported as a comorbidity in ASDs, indicating gut-brain axis as a novel emerging approach. Recently, a central role for peroxisome-proliferator activated receptor (PPAR)-α has been addressed in neurological functions, associated with the behaviour. Among endogenous lipids, palmitoylethanolamide (PEA), a PPAR-α agonist, has been extensively studied for its anti-inflammatory effects both at central and peripheral level. Based on this background, the aim of this study was to investigate the pharmacological effects of PEA on autistic-like behaviour of BTBR T+tf/J mice and to shed light on the contributing mechanisms. Our results showed that PEA reverted the altered behavioural phenotype of BTBR mice, and this effect was contingent to PPAR-α activation. Moreover, PEA was able to restore hippocampal BDNF signalling pathway, and improve mitochondrial dysfunction, both pathological aspects, known to be consistently associated with ASDs. Furthermore, PEA reduced the overall inflammatory state of BTBR mice, reducing the expression of pro-inflammatory cytokines at hippocampal, serum, and colonic level. The analysis of gut permeability and the expression of colonic tight junctions showed a reduction of leaky gut in PEA-treated BTBR mice. This finding together with PEA effect on gut microbiota composition suggests an involvement of microbiota-gut-brain axis. In conclusion, our results demonstrated a therapeutic potential of PEA in limiting ASD symptoms, through its pleiotropic mechanism of action, supporting neuroprotection, anti-inflammatory effects, and the modulation of gut-brain axis

An orally administered butyrate-releasing derivative reduces neutrophil recruitment and inflammation in dextran sulphate sodium-induced murine colitis

BACKGROUND AND PURPOSE: Butyrate has shown benefits in inflammatory bowel diseases. However, it is not often administered orally because of its rancid smell and unpleasant taste. The efficacy of a more palatable butyrate-releasing derivative, N-(1-carbamoyl-2-phenylethyl) butyramide (FBA), was evaluated in a mouse model of colitis induced by dextran sodium sulphate (DSS). EXPERIMENTAL APPROACH: Male 10 week-old BALB/c mice received DSS (2.5%) in drinking water (for 5 days) followed by DSS-free water for 7 days (DSS group). Oral FBA administration (42.5 mg·kg-1 ) was started 7 days before DSS as preventive (P-FBA), or 2 days after DSS as therapeutic (T-FBA); both treatments lasted 19 days. One DSS-untreated group received only tap water (CON). KEY RESULTS: FBA treatments reduced colitis symptoms and colon damage. P-FBA and T-FBA significantly decreased polymorphonuclear cell infiltration score compared with the DSS group. FBA reversed the imbalance between pro- and anti-inflammatory cytokines (reducing inducible NOS protein expression, CCL2 and IL-6 transcripts in colon and increasing TGFβ and IL-10). Morever, P-FBA and T-FBA limited neutrophil recruitment (by expression and localization of the neutrophil granule protease Ly-6G), restored deficiency of the butyrate transporter and improved intestinal epithelial integrity, preventing tight-junction impairment (zonulin-1 and occludin). FBA, similar to its parental compound sodium butyrate, inhibited histone deacetylase-9 and restored H3 histone acetylation, exerting an anti-inflammatory effect through NF-κB inhibition and the up-regulation of PPARγ. CONCLUSIONS AND IMPLICATIONS: FBA reduces inflammatory intestinal damage in mice indicating its potential as a postbiotic derivative without the problems associated with the oral administration of sodium butyrate

The Hepatic Mitochondrial Alterations Exacerbate Meta-Inflammation in Autism Spectrum Disorders

The role of the liver in autism spectrum disorders (ASD), developmental disabilities characterized by impairments in social interactions and repetitive behavioral patterns, has been poorly investigated. In ASD, it has been shown a dysregulation of gut-brain crosstalk, a communication system able to influence metabolic homeostasis, as well as brain development, mood and cognitive functions. The liver, with its key role in inflammatory and metabolic states, represents the crucial metabolic organ in this crosstalk. Indeed, through the portal vein, the liver receives not only nutrients but also numerous factors derived from the gut and visceral adipose tissue, which modulate metabolism and hepatic mitochondrial functions. Here, we investigated, in an animal model of ASD (BTBR mice), the involvement of hepatic mitochondria in the regulation of inflammatory state and liver damage. We observed increased inflammation and oxidative stress linked to hepatic mitochondrial dysfunction, steatotic hepatocytes, and marked mitochondrial fission in BTBR mice. Our preliminary study provides a better understanding of the pathophysiology of ASD and could open the way to identifying hepatic mitochondria as targets for innovative therapeutic strategies for the disease

Moving Dirac nodes by chemical substitution

Dirac fermions play a central role in the study of topological phases, for they can generate a variety of exotic states, such as Weyl semimetals and topological insulators. The control and manipulation of Dirac fermions constitute a fundamental step toward the realization of novel concepts of electronic devices and quantum computation. By means of Angle-Resolved PhotoEmission Spectroscopy (ARPES) experiments and ab initio simulations, here, we show that Dirac states can be effectively tuned by doping a transition metal sulfide, BaNiS2, through Co/Ni substitution. The symmetry and chemical characteristics of this material, combined with the modification of the charge-transfer gap of BaCo1-xNixS2 across its phase diagram, lead to the formation of Dirac lines, whose position in k-space can be displaced along the Gamma - M symmetry direction and their form reshaped. Not only does the doping x tailor the location and shape of the Dirac bands, but it also controls the metal-insulator transition in the same compound, making BaCo1-xNixS2 a model system to functionalize Dirac materials by varying the strength of electron correlations