Bulimia Nervosa and Depression, from the Brain to the Gut Microbiota and Back.

Bulimia nervosa (BN) is a condition marked by a typical cyclical behavioural activity, characterized by restrictions, binges and vomiting, as well as a disturbance of the emotional value of food. Food stimuli acquire excessive relevance, giving rise to a succession of states of excitement and anxiety. The depressive condition accompanies very often BN. Most people with BN also experience one or more anxiety disorders. The aim of the review is to identify a link at a central and peripheral level that connects an eating disorder with a mood state. Altered nervous mechanisms are involved in BN. Among the cerebral areas, the insula is functionally compromised in BN. The insula is also implicated in depressive states. The insula is the primary gustatory cortex, where gustatory sensory information such as taste discrimination and higher cognitive functions such as food anticipation and reward are processed. The insula is anatomically connected to a wide range of cortical, limbic and paralimbic structures, and functionally implicated in high-order cognition, emotional responses, and empathic processes. The insula plays a crucial role in empathy, or in the ability to share the emotional states of others, and in particular negative emotions. In fact, the insular cortex is also activated in conditions of anxiety and depression. One of the pathophysiological factors that influences bulimia and depression is the composition of gut microbiota, as there is a strong association between the microbial signature and the brain function. Gut dysbiosis condition may contribute to the development of eating disorders, including BN. Dysbiosis may promote intestinal inflammation, alter gut permeability, and trigger immune reactions in the hunger/satiety regulation center contributing to the pathophysiological development of eating disorders. From this emerges the importance of adequate probiotic integration as a preventive and/or therapeutic tool in these pathologies.

Mast Cells in Human Health and Diseases 2.0.

This Special Issue collects some scientific pieces of the multifaceted research on the mast cell (MC), and it intends to highlight the broad spectrum of activity that MCs have, both in physiological conditions and in pathological states, focusing attention on some of them [...].

The Neurotransmission Basis of Post-Traumatic Stress Disorders by the Fear Conditioning Paradigm.

Fear conditioning constitutes the best and most reproducible paradigm to study the neurobiological mechanisms underlying emotions. On the other hand, studies on the synaptic plasticity phenomena underlying fear conditioning present neural circuits enforcing this learning pattern related to post-traumatic stress disorder (PTSD). Notably, in both humans and the rodent model, fear conditioning and context rely on dependent neurocircuitry in the amygdala and prefrontal cortex, cingulate gyrus, and hippocampus. In this review, an overview of the role that classical neurotransmitters play in the contextual conditioning model of fear, and therefore in PTSD, was reported.

Modulation of synapse-related gene expression in the cerebellum and prefrontal cortex of rats subjected to the contextual fear conditioning paradigm.

The contextual fear conditioning (CFC) paradigm is the most productive approach for understanding the neurobiology of learning and memory as it allows to follow the evolution of memory traces of a conditioned stimulus and a specific context. The formation of long-term memory involves alterations in synaptic efficacy and neural transmission. It is known that the prefrontal cortex (PFC) exerts top-down control over subcortical structures to regulate behavioural responses. Moreover, cerebellar structures are involved in storing conditioned responses. The purpose of this research was to determine if the response to conditioning and stressful challenge is associated with alterations in synapse-related genes mRNA levels in the PFC, cerebellar vermis (V), and hemispheres (H) of young adult male rats. Four groups of Wistar rats were examined: naïve, CFC, shock only (SO), and exploration (EXPL). The behavioural response was evaluated by measuring the total freezing duration. Real-Time PCR was employed to quantify mRNA levels of some genes involved in synaptic plasticity. The results obtained from this study showed alterations in gene expression in different synapse-related genes after exposure to stressful stimuli and positioning to new environment. In conclusion, conditioning behavioural stimuli change the expression profile of molecules involved in neural transmission.

Mast Cells in Human Health and Diseases.

This Special Issue includes articles that discuss several important aspects regarding the role of mast cells (MCs) and elucidate some cellular and molecular mechanisms of these multifaceted cells [...].

The Crosstalk between Intestinal Epithelial Cells and Mast Cells Is Modulated by the Probiotic Supplementation in Co-Culture Models.

The intestinal epithelium constitutes a selectively permeable barrier between the internal and external environment that allows the absorption of nutrients, electrolytes, and water, as well as an effective defense against intraluminal bacteria, toxins, and potentially antigenic material. Experimental evidence suggest that intestinal inflammation is critically dependent on an imbalance of homeostasis between the gut microbiota and the mucosal immune system. In this context, mast cells play a crucial role. The intake of specific probiotic strains can prevent the development of gut inflammatory markers and activation of the immune system. Here, the effect of a probiotic formulation containing L. rhamnosus LR 32, B. lactis BL04, and B. longum BB 536 on intestinal epithelial cells and mast cells was investigated. To mimic the natural host compartmentalization, Transwell co-culture models were set up. Co-cultures of intestinal epithelial cells interfaced with the human mast cell line HMC-1.2 in the basolateral chamber were challenged with lipopolysaccharide (LPS), and then treated with probiotics. In the HT29/HMC-1.2 co-culture, the probiotic formulation was able to counteract the LPS-induced release of interleukin 6 from HMC-1.2, and was effective in preserving the epithelial barrier integrity in the HT29/Caco-2/ HMC-1.2 co-culture. The results suggest the potential therapeutic effect of the probiotic formulation.

In vitro toxicological assessment of PhSeZnCl in human liver cells.

Phenylselenenylzinc chloride (PhSeZnCl) is an air-stable selenolate, easily synthesizable through oxidative insertion of elemental zinc into the Se-halogen bond of the commercially available phenylselenyl chloride. PhSeZnCl was shown to possess a marked GPx-like activity both in NMR and in vitro tests, and to effectively react with cellular thiols, and was supposed for a potential use in the chemotherapy of drug-resistant cancers. However, activity of PhSeZnCl in hepatic cells has never been tested before now. In this in vitro approach, we evaluated the cytotoxic, genotoxic, and apoptotic activities, as well as the effects on cell cycle of PhSeZnCl in two preclinical hepatic models, namely HepG2 and HepaRG cells. Results showed that cell viability of HepG2 and HepaRG cells decreased in a dose-dependent manner, with a more marked effect in HepG2 tumour cells. Moreover, treatment with 50 µg/mL PhSeZnCl caused an increase of primary DNA damage (4 h) and a statistically significant increase of HepG2 cells arrested in G2/M phase. In addition, it altered mitochondrial membrane potential and induced chromosomal DNA fragmentation (24 h). In HepaRG cells, PhSeZnCl was able to determine a cell cycle-independent induction of apoptosis. Particularly, 50 µg/mL induced mitochondrial membrane depolarization after 24 h and apoptosis after 4 h treatment. Futhermore, all PhSeZnCl concentrations tested determined a significant increase of apoptotic cells after 24 h. Apoptosis was also highlighted by the detection of active Caspase-3 by Western Blot analysis after 24 h exposure. In conclusion, this first toxicological assessment provides new insights into the biological activity of PhSeZnCl in preclinical hepatic models that will be useful in future safety assessment investigation of this compound as a potential pharmaceutical. Supplementary Information: The online version contains supplementary material available at 10.1007/s43188-022-00148-y.

Neuroinflammation in the Brain and Role of Intestinal Microbiota: An Overview of the Players.

Great interest is aimed at understanding the inflammatory responses at the level of the central nervous system (CNS), referred to as neuroinflammatory. The environment and the duration of the inflammatory responses are essential factors for comprehending the biochemical and pathophysiological consequences induced by the inflammatory state. Specific inducers of inflammation associated with neurodegenerative disorders can activate inflammatory processes and produce mediators that potentiate neurodegeneration. Immune responders in the brain include microglial cells, astrocytes, and mast cells. A number of human pathologies are recognized to have an inflammatory component, including disorders related to brain function. Emerging evidence also attributes an important role to intestinal microorganisms in disorders related to brain function. In the gut-brain axis, the intestinal microbiota produce a variety of molecules and neurotransmitters, transform primary bile acids into secondary bile, and synthesize short-chain fatty acids. Communication within the gut-brain axis occurs through several pathways, including the immune system, the enteric nervous system, the vagus nerve, and the production of microbial metabolites. The CNS responds to this input from the gut by modulating the activity of the autonomic nervous system and the hypothalamic-pituitary-adrenal axis, which manages adrenocortical hormones. In this perspective, gut microbiota may influence neural function by influencing microglia, astroglia, and mast cells. Conversely, the relationship between neurons, microglia and synaptic alteration may also involve gut microbiota. The purpose of this review is to provide a concise overview of the mechanisms involved in communication between intestinal microbiota and the brain and how this contributes to the management of neuroinflammation.

The Connection between Gut and Lung Microbiota, Mast Cells, Platelets and SARS-CoV-2 in the Elderly Patient.

The human coronavirus SARS-CoV-2 or COVID-19 that emerged in late 2019 causes a respiratory tract infection and has currently resulted in more than 627 million confirmed cases and over 6.58 million deaths worldwide up to October 2022. The highest death rate caused by COVID-19 is in older people, especially those with comorbidities. This evidence presents a challenge for biomedical research on aging and also identifies some key players in inflammation, including mast cells and platelets, which could represent important markers and, at the same time, unconventional therapeutic targets. Studies have shown a decrease in the diversity of gut microbiota composition in the elderly, particularly a reduced abundance of butyrate-producing species, and COVID-19 patients manifest faecal microbiome alterations, with an increase in opportunistic pathogens and a depletion of commensal beneficial microorganisms. The main purpose of this narrative review is to highlight how an altered condition of the gut microbiota, especially in the elderly, could be an important factor and have a strong impact in the lung homeostasis and COVID-19 phenomenon, jointly to the activation of mast cells and platelets, and also affect the outcomes of the pathology. Therefore, a targeted and careful control of the intestinal microbiota could represent a complementary intervention to be implemented for the management and the challenge against COVID-19.

A Multi-Strain Probiotic Formulation Improves Intestinal Barrier Function by the Modulation of Tight and Adherent Junction Proteins.

In healthy individuals, tight junction proteins (TJPs) maintain the integrity of the intestinal barrier. Dysbiosis and increased intestinal permeability are observed in several diseases, such as inflammatory bowel disease. Many studies highlight the role of probiotics in preventing intestinal barrier dysfunction. The present study aims to investigate the effects of a commercially available probiotic formulation of L. rhamnosus LR 32, B. lactis BL 04, and B. longum BB 536 (Serobioma, Bromatech s.r.l., Milan, Italy) on TJPs and the integrity of the intestinal epithelial barrier, and the ability of this formulation to prevent lipopolysaccharide-induced, inflammation-associated damage. An in vitro model of the intestinal barrier was developed using a Caco-2 cell monolayer. The mRNA expression levels of the TJ genes were analyzed using real-time PCR. Changes in the amounts of proteins were assessed with Western blotting. The effect of Serobioma on the intestinal epithelial barrier function was assessed using transepithelial electrical resistance (TEER) measurements. The probiotic formulation tested in this study modulates the expression of TJPs and prevents inflammatory damage. Our findings provide new insights into the mechanisms by which probiotics are able to prevent damage to the gut epithelial barrier.

Effect of packaging and storage conditions on some quality traits of bovine meat.

Packaging is considered one of the most interesting technological aspects of food production and is a constantly evolving subject in food production. The type of packaging is important for the quality and safety of the product and for the visual appearance of the product to be immediately evaluated by consumers. The purpose of this study was to investigate the effect of four different types of modified atmosphere packaging (ATM) and vacuum packaging (VP) currently used by a company in central Italy, on the main qualitative characteristics of beef. For these two traditional and two new solutions with reduced environmental impact and compostable were evaluated. For each type of packaging, two different products were analyzed: steaks and hamburgers. The samples, immediately after production, were transported to the laboratory in refrigerated containers. Several parameters (color, pH, water holding capacity, drip loss, and microbiological characteristics) were evaluated at time 0 and after 7 (T7), 14 (T14) and 21 days (T21) of storage in the dark and at refrigeration temperature (+4°C ± 2°C). The results showed that the two types of packaging have very similar effects on the water-retaining capacity of the steaks. More noticeable differences were recorded by the colorimetric analysis: for both steaks and hamburgers, the products packaged in the traditional packaging appeared brighter and redder than those packaged in the new alternatives. The microbiological analysis of the steaks showed higher values in the "new" packaging. The formation of abundant ropy slime was observed in one of the samples in the "new" modified atmosphere package at T21. The results of this study showed that the technological characteristics (in particular, the color) and the microbiological characteristics of the steaks and hamburgers were better in "old" packaging, with a better appearance and a longer shelf life. The results obtained show how the research for eco-sustainable products for packaging must be addressed, taking into account the effect of the materials on the qualitative and hygienic- sanitary characteristics of the meat.

Molecular Insights in Psychiatry.

This Special Issue included articles discussing several important psychiatric phenomena whose elucidation can be provided by cellular and subcellular molecular mechanisms [...].

The Inflammatory Conspiracy in Multiple Sclerosis: A Crossroads of Clues and Insights through Mast Cells, Platelets, Inflammation, Gut Microbiota, Mood Disorders and Stem Cells.

Multiple Sclerosis is a chronic neurological disease characterized by demyelination and axonal loss. This pathology, still largely of unknown etiology, carries within it a complex series of etiopathogenetic components of which it is difficult to trace the origin. An inflammatory state is likely to be the basis of the pathology. Crucial elements of the inflammatory process are the interactions between platelets and mast cells as well as the bacterial component of the intestinal microbiota. In addition, the involvement of mast cells in autoimmune demyelinating diseases has been shown. The present work tries to hang up on that Ariadne's thread which, in the molecular complexity of the interactions between mast cells, platelets, microbiota and inflammation, characterizes Multiple Sclerosis and attempts to bring the pathology back to the causal determinism of psychopathological phenomenology. Therefore, we consider the possibility that the original error of Multiple Sclerosis can be investigated in the genetic origin of the depressive pathology.

The role of mast cells in the gut and brain.

Mast cells are the major effectors in allergic reactions through degranulation and release of inflammatory, vasoactive and nociceptive mediators associated with the pathogenesis of a variety of inflammatory disorders. Mast cells are strategically positioned as gatekeepers at host/environment interfaces, like the skin, airways, gastrointestinal and urogenital tracts, and their presence also in the brain allows them to act not only as sentinels of invading microorganisms but also as targets to respond to different allergens, pathogens and other dangerous agents that can be ingested, inhaled or encountered after the breakdown of the epithelial barrier. Mast cells can respond to any change in the environment by communicating with the different cells involved in the immune response and giving rise to an amplification signal network through feedback loops. They secrete both preformed mediators within minutes of stimulation and de novo synthesized molecules acting as effectors in the relationship between nervous, vascular and immune systems. For this peculiarity, mast cells are master regulators and key players of the immune system and important sources of essential and beneficial mediators with crucial roles in regulating various physiological processes.

Learning processes in elementary nervous systems§.

Invertebrate animal models show simple behaviors supported by neural circuits easily accessible for experimentation and yet complex enough to provide necessary information on the cellular and molecular mechanisms that govern the vertebrate nervous system's function. The mechanisms underlying simple forms of learning have been extensively studied in the marine gastropod Aplysia californica, in which elementary non-associative learning of the behavioral habituation and sensitization type has been studied using the gill withdrawal reflex. A strong stimulus applied to the neck or tail improves the reflex response through heterosynaptic facilitation. The neurotransmitter serotonin is involved in both behavioral sensitization and dishabituation by acting through the second messenger cyclic adenosine monophosphate, protein kinase A, the phosphorylation of a K+ channel, causing its closure. This broadens the action potential profile, increases the influx of Ca2+ through voltage-gated Ca2+ channels, and enhances the neurotransmitter glutamate's release. Short-term memory is based on covalent modifications of pre-existing proteins, while long-term memory requires gene transcription, protein translation and growth of new synapses. Another simple invertebrate model is the leech Hirudo medicinalis. In nearly-intact preparations, the repetitive application of light electrical stimuli at the level of the caudal portion of the body wall can induce the habituation of swimming induction. At the same time, the stroke on the dorsal skin generates behavioral sensitization or dishabituation. Knowledge of the molecular mechanisms of activity-dependent forms of synaptic plasticity provides a basis for understanding the mechanisms underlying learning, memory, other forms of brain plasticity, and pathological conditions and suggests potential therapeutic interventions.

The Prophylactic Use of Bovine Colostrum in a Murine Model of TNBS-Induced Colitis.

This study investigated the effects of a short-term administration of bovine colostrum (BC) in a TNBS model of induced colitis. Colitis was induced by TNBS treatment after seven days of BC (BC group, n = 12) or saline (control group, n = 12) administration in mice. Clinical signs, histopathological characteristics, expression levels of Toll-like receptor 4 (TLR4), pro- and anti-inflammatory cytokines, and microbial composition were assessed. BC was well tolerated and did not induce any histological damage or clinical symptoms. After TNBS treatment, the BC group showed a reduction in body weight (BW) loss compared to Control (p < 0.05). Moreover, expression levels of TLR4 (p < 0.01), Interleukin-1ß (IL-1ß; p < 0.001), Interleukin-8 (IL-8; p < 0.001), and Interleukin-10 (IL-10; p < 0.001) were lower in mice administered with BC. Finally, Escherichia coli were higher (p < 0.05), while Enterococci (p < 0.001), Lactobacillus spp. (p < 0.001), and Bifidobacterium spp. (p < 0.05) were lower in Control than BC group. This study confirms that pre-treatment with BC modulates the expression of genes and the count of microbes involved in the etiopathogenesis of colitis.

How to Assess in vitro Probiotic Viability and the Correct Use of Neutralizing Agents.

Probiotic viability is generally determined by quantifying its resistance to simulated gastric juice or to simulated intestinal fluid in in vitro tests, which measure microbial survival after given periods of contact. The use of a neutralizing agent is needed to avoid a carry-over of gastric or intestinal juice into the culture media of the subsequent analysis and to avoid any antimicrobial effect extended over the defined period of contact of the test. Neutralization of gastric juice and intestinal juice are of the utmost importance to present data accurately. Failing to do so determines a carry-over of bactericidal activity to the plates used for the enumeration, which further reduces the number of surviving cells. Examples of such incorrect adaptation of the test are available in literature. The purpose of this perspective stems from the discovery that many studies do not adhere to internationally recognized standards, e.g., EN 1040:2005 (European Committee for Standardization [ECS], 2005), to evaluate the basic, bactericidal activity of compounds, especially for the neutralization step.

In Vitro Anti-Inflammatory Effects of Phenolic Compounds from Moraiolo Virgin Olive Oil (MVOO) in Brain Cells via Regulating the TLR4/NLRP3 Axis.

Neuroinflammation is a feature of many classic neurodegenerative diseases. In the healthy brain, microglia cells are distributed throughout the brain and are constantly surveilling the central nervous system (CNS). In response to CNS injury, microglia quickly react by secreting a wide array of apoptotic molecules. Virgin olive oil (VOO) is universally recognized as a symbol of the Mediterranean diet. In the current study, using lipopolysaccharide (LPS)-stimulated BV2 microglia, the anti-inflammatory effects of VOO phenolic extracts from Moraiolo cultivar (MVOO-PE) were investigated. The results showed that low concentration of MVOO-PE prevented microglia cell death and attenuated the LPS-induced activation of toll-like receptor 4 (TLR4)/NOD-like receptor pyrin domain-containing-3 (NLRP3) signaling cascade. The levels of TLR4 and NF-kB were diminished, as well as NLRP3 inflammasome and interleukin-1ß (IL-1ß) production. Cyclooxygenase-2 (COX-2) isoenzyme and ionized calcium binding adaptor molecule 1 (Iba-1) inflammatory mediator were also reduced. By modulating the TLR4/NLRP3 axis, MVOO-PE pretreatment was able to significantly down-regulate the mRNA expression of inflammatory mediators and suppress the cytokine secretion. Finally, we showed protective effect of MVOO-PE in a transwell neuron-microglia co-culture system. In conclusion, these results suggest that MVOO-PE could exerts anti-inflammatory activity on brain cells and become a promising candidate for preventing several neuroinflammatory diseases.

Neutral Sphingomyelinase Modulation in the Protective/Preventive Role of rMnSOD from Radiation-Induced Damage in the Brain.

Studies on the relationship between reactive oxygen species (ROS)/manganese superoxide dismutase (MnSOD) and sphingomyelinase (SMase) are controversial. It has been demonstrated that SMase increases the intracellular ROS level and induces gene expression for MnSOD protein. On the other hand, some authors showed that ROS modulate the activation of SMase. The human recombinant manganese superoxide dismutase (rMnSOD) exerting a radioprotective effect on normal cells, qualifies as a possible pharmaceutical tool to prevent and/or cure damages derived from accidental exposure to ionizing radiation. This study aimed to identify neutral SMase (nSMase) as novel molecule connecting rMnSOD to its radiation protective effects. We used a new, and to this date, unique, experimental model to assess the effect of both radiation and rMnSOD in the brain of mice, within a collaborative project among Italian research groups and the Joint Institute for Nuclear Research, Dubna (Russia). Mice were exposed to a set of minor γ radiation and neutrons and a spectrum of neutrons, simulating the radiation levels to which cosmonauts will be exposed during deep-space, long-term missions. Groups of mice were treated or not-treated (controls) with daily subcutaneous injections of rMnSOD during a period of 10 days. An additional group of mice was also pretreated with rMnSOD for three days before irradiation, as a model for preventive measures. We demonstrate that rMnSOD significantly protects the midbrain cells from radiation-induced damage, inducing a strong upregulation of nSMase gene and protein expression. Pretreatment with rMnSOD before irradiation protects the brain with a value of very high nSMase activity, indicating that high levels of activity might be sufficient to exert the rMnSOD preventive role. In conclusion, the protective effect of rMnSOD from radiation-induced brain damage may require nSMase enzyme.

Mast Cells in Gut and Brain and Their Potential Role as an Emerging Therapeutic Target for Neural Diseases.

The mast cells (MCs) are the leader cells of inflammation. They are well known for their involvement on allergic reactions through degranulation and release of vasoactive, inflammatory, and nociceptive mediators. Upon encountering potential danger signal, MCs are true sensors of the environment, the first to respond in rapid and selective manner. The MC activates the algic response and modulates the evolution of nociceptive pain, typical of acute inflammation, to neuropathic pain, typical not only of chronic inflammation but also of the dysregulation of the pain system. Yet, MC may contribute to modulate intensity of the associated depressive and anxiogenic component on the neuronal and microglial biological front. Chronic inflammation is a common mediator of these co-morbidities. In parallel to the removal of the etiological factors of tissue damage, the modulation of MC hyperactivity and the reduction of the release of inflammatory factors may constitute a new frontier of pharmacological intervention aimed at preventing the chronicity of inflammation, the evolution of pain, and also the worsening of the depression and anxiogenic state associated with it. So, identifying specific molecules able to modify MC activity may be an important therapeutic tool. Various preclinical evidences suggest that the intestinal microbiota contributes substantially to mood and behavioral disorders. In humans, conditions of the microbiota have been linked to stress, anxiety, depression, and pain. MC is likely the crucial neuroimmune connecting between these components. In this review, the involvement of MCs in pain, stress, and depression is reviewed. We focus on the MC as target that may be mediating stress and mood disorders via microbiota-gut-brain axis.