Vascularized versus Free Nerve Grafts: An Experimental Study on Rats.

BACKGROUND: Vascularized nerve grafts (VNGs) have been proposed as a superior alternative to free nerve grafts (FNGs) for complex nerve defects. A greater regenerative potential has been suggested by clinical and experimental studies, but conclusive evidence is still lacking. METHODS: In this experimental study, 10 adult male Wistar rats received a non-vascularized orthotopic sciatic nerve graft on their right side, and a vascularized orthotopic sciatic nerve graft nerve on their left side. Functional outcome following nerve regeneration was evaluated through electrodiagnostic studies, target muscles weight and histomorphology, and data of VNGs and FNGs were compared. RESULTS: The results of this study showed a significant difference in the motor unit number of Gastrocnemius Medialis (GM) estimated by MUNE in the VNG side compared to the FNG side. No other significant differences in axonal regeneration and muscle reinnervation were evident at either electrodiagnostic, histomorphology studies or muscle weight. CONCLUSIONS: This experimental model showed slight differences in nerve regeneration between VNGs and FNGs, but cannot support a high clinical advantage for VNGs. The results of this study show that VNGs are not strongly superior to FNGs in the rat model, even in avascular beds. Clinical advantages of VNGs are likely to be limited to extensive and thick nerve defects and can only be assessed on experimental model with bigger animals. Also, we showed that the MUNE technique provided a reliable and reproducible evaluation of functional outcomes in the rat sciatic nerve and defined a reproducible protocol for functional evaluation of muscle reinnervation.

Red and golden tomato administration improves fat diet-induced hepatic steatosis in rats by modulating HNF4α, Lepr, and GK expression.

Introduction: Nonalcoholic fatty liver disease (NAFLD), characterized by lipid accumulation within hepatocytes exceeding 5% of liver weight, is strongly related to metabolic disorders, obesity, and diabetes and represents a health emergency worldwide. There is no standard therapy available for NAFLD. Lifestyle intervention, including phytonutrient intake, is key in preventing NAFLD development and progression. Methods: We used a rat model of NAFLD to evaluate the effect of dietary supplementation with red tomato (RT) and golden tomato (GT)-a patented mix of fruit with varying degrees of ripeness and particularly rich in naringenin and chlorogenic acid-after steatosis development. We assessed the effects on body weight, metabolic profile, and hepatic steatosis. Results and discussion: We found a correlation between the amelioration of all the parameters and the liver gene expression. Our results showed that, together with the reversion of steatosis, the consumption of RT and GT can cause a significant reduction in triglycerides, low-density lipoprotein-cholesterol, fasting glucose, and homeostasis model assessment index. Meanwhile, we observed an increase in high-density lipoprotein-cholesterol according to the amelioration of the general lipidic profile. Regarding hepatic gene expression, we found the upregulation of Gk and Hnf4α involved in metabolic homeostasis, Lepr involved in adipokine signaling, and Il6 and Tnf involved in inflammatory response. Taken together, our results suggest that dietary intake of red and golden tomatoes, as a nutraceutical approach, has potential in preventing and therapeutics of NAFLD.

Reducing Visuospatial Pseudoneglect in Healthy Subjects by Active Video Gaming.

Pseudoneglect phenomenon refers to a condition in which healthy subjects tend to perceive the left side of exactly bisected lines as being slightly longer than the right one. However, behavioural data showed that athletes practising an open-skill sport display less pseudoneglect than the general population. Given the fact that so-called exergames (also known as active video games) are platforms designed to fully mimic sport activity, this work intends to investigate whether and how a one-week training period of exergame open-skill sport can determine a similar decrease in pseudoneglect. Fifteen healthy participants (non-athletes) responded to a visuospatial attention task and a control memory task in basal conditions (t0: Pre-game) and after a short period (one week, one hour/day) of tennis exergaming (t1: Post-game). In the Post-game condition, subjects from this experimental group (ExerGame group: EG) reduced leftward space overestimation and made significantly fewer leftward errors compared to the Pre-game condition. Additionally, two other experimental groups were employed: one evaluated within the same conditions of the main experiment but using a non-exergame (Non-Exergame groups: NEG) and the other one without any video game stimulus (Sedentary group: SE). Our findings suggest that daily training of a tennis exergame seems to be able to improve visuospatial attention isotropy by reducing leftward space overestimation, whereas outcomes from non-exergaming and sedentary activity do not modify subjects' performance.

"Golden" Tomato Consumption Ameliorates Metabolic Syndrome: A Focus on the Redox Balance in the High-Fat-Diet-Fed Rat.

Tomato fruits defined as "golden" refer to a food product harvested at an incomplete ripening stage with respect to red tomatoes at full maturation. The aim of this study is to explore the putative influence of "golden tomato" (GT) on Metabolic Syndrome (MetS), especially focusing on the effects on redox homeostasis. Firstly, the differential chemical properties of the GT food matrix were characterized in terms of phytonutrient composition and antioxidant capacities with respect to red tomato (RT). Later, we assessed the biochemical, nutraceutical and eventually disease-modifying potential of GT in vivo in the high-fat-diet rat model of MetS. Our data revealed that GT oral supplementation is able to counterbalance MetS-induced biometric and metabolic modifications. Noteworthy is that this nutritional supplementation proved to reduce plasma oxidant status and improve the endogenous antioxidant barriers, assessed by strong systemic biomarkers. Furthermore, consistently with the reduction of hepatic reactive oxygen and nitrogen species (RONS) levels, treatment with GT markedly reduced the HFD-induced increase in hepatic lipid peroxidation and hepatic steatosis. This research elucidates the importance of food supplementation with GT in the prevention and management of MetS.

Modulation of Human Motor Cortical Excitability and Plasticity by Opuntia Ficus Indica Fruit Consumption: Evidence from a Preliminary Study through Non-Invasive Brain Stimulation.

Indicaxanthin (IX) from Opuntia Ficus Indica (OFI) has been shown to exert numerous biological effects both in vitro and in vivo, such as antioxidant, anti-inflammatory, neuro-modulatory activity in rodent models. Our goal was to investigate the eventual neuro-active role of orally assumed fruits containing high levels of IX at nutritionally-relevant amounts in healthy subjects, exploring cortical excitability and plasticity in the human motor cortex (M1). To this purpose, we applied paired-pulse transcranial magnetic stimulation and anodal transcranial direct current stimulation (a-tDCS) in basal conditions and followed the consumption of yellow cactus pear fruits containing IX or white cactus pear fruits devoid of IX (placebo). Furthermore, resting state-functional MRI (rs-fMRI) preliminary acquisitions were performed before and after consumption of the same number of yellow fruits. Our data revealed that the consumption of IX-containing fruits could specifically activate intracortical excitatory circuits, differently from the placebo-controlled group. Furthermore, we found that following the ingestion of IX-containing fruits, elevated network activity of glutamatergic intracortical circuits can homeostatically be restored to baseline levels following a-tDCS stimulation. No significant differences were observed through rs-fMRI acquisitions. These outcomes suggest that IX from OFI increases intracortical excitability of M1 and leads to homeostatic cortical plasticity responses.

Guanosine modulates K+ membrane currents in SH-SY5Y cells: involvement of adenosine receptors.

Guanosine (GUO), widely considered a key signaling mediator, is implicated in the regulation of several cellular processes. While its interaction with neural membranes has been described, GUO still is an orphan neuromodulator. It has been postulated that GUO may eventually interact with potassium channels and adenosine (ADO) receptors (ARs), both particularly important for the control of cellular excitability. Accordingly, here, we investigated the effects of GUO on the bioelectric activity of human neuroblastoma SH-SY5Y cells by whole-cell patch-clamp recordings. We first explored the contribution of voltage-dependent K+ channels and, besides this, the role of ARs in the regulation of GUO-dependent cellular electrophysiology. Our data support that GUO is able to specifically modulate K+-dependent outward currents over cell membranes. Importantly, administering ADO along with GUO potentiates its effects. Overall, these results suggested that K+ outward membrane channels may be targeted by GUO with an implication of  ADO receptors in SH-SY5Y cells, but also support the hypothesis of a functional interaction of the two ligands. The present research runs through the leitmotif of the deorphanization of GUO, adding insight on the interplay with adenosinergic signaling and suggesting GUO as a powerful modulator of SH-SY5Y excitability.

TRPV1 channels in nitric oxide-mediated signalling: insight on excitatory transmission in rat CA1 pyramidal neurons.

Nitric oxide (NO) is a fascinating signalling molecule implicated in a plethora of biological functions, especially at the synaptic level. Exploring neurotransmission in the hippocampus could be instrumental in the individuation of putative targets for nitric-oxide mediated neuromodulation, especially in terms of the potential repercussions on fundamental processes i.e. synaptic plasticity and excitability-related phenomena. Among these targets, endovanilloid signalling constitutes an object of study since Transient Receptors Vanilloid type 1 (TRPV1) channels possess a NO-sensitive gate modulating its activation. Also, NO has been referred to as a mediator for numerous endocannabinoid effects. Notwithstanding, the linkage between TRPV1 and NO systems in neuromodulation still remains elusive. To this end, we aim at investigating the involvement of TRPV1 in nitric oxide-mediated influence on hippocampal processes. Electrophysiological whole-cell recordings in CA1 pyramidal neurons were applied to evaluate excitatory neurotransmission in rat brain slices. Indeed, miniature excitatory postsynaptic currents (mEPSCs) were analysed upon pharmacological manipulation of TRPV1 and NO signalling pathways. In detail, only the administration of the specific TRPV1 exogenous agonist - capsaicin - reduced the frequency and amplitude of mEPSC similarly to the inhibitor of neuronal nitric oxide synthase (nNOS), 7-nitroindazole (7NI). In contrast, capsazepine, TRPV1 antagonist, does not influence excitatory transmission. The combined TRPV1 activation and nNOS blockade confirm the presence of a putative common mechanism. When we administered the endovanilloid-endocannabinoid ligand, i.e. anandamide, we unveiled a potentiation of neurotransmission that was selectively reverted by 7NI. Our data suggest that nitric oxide influences TRPV1 hippocampal signalling since these channels are not constitutively active, but can be "on-demand" activated to modulate excitation in CA1 pyramidal neurons, and that this effect is linked to nitric oxide production.

Ketogenic and Modified Mediterranean Diet as a Tool to Counteract Neuroinflammation in Multiple Sclerosis: Nutritional Suggestions.

Ketogenic Diet is a nutritional pattern often used as dietotherapy in inflammatory diseases, including neurological disorders. Applied on epileptic children since 1920, in recent years it has been taken into account again as a tool to both reduce inflammatory burdens and ameliorate the nutritional status of patients affected by different pathologies. Multiple sclerosis (MS) is considered an immune-mediated neuro-inflammatory disease and diet is a possible factor in its pathogenesis. The aim of this work is to investigate the main potential targets of MS-related impairments, in particular the cognitive deficits, focusing on the alteration of biomarkers such as the Brain Derived-Neurotrophic Factor and the Tryptophan/Kynurenine ratio that could play a role on neuroprotection and thus on MS progression. Furthermore, we here propose nutritional suggestions which are useful in the development of a ketogenic diet protocol that takes advantage of the anti-inflammatory properties of low-carbohydrate foods from the Mediterranean diet to be applied to subjects with MS. In conclusion, this approach will allow one to develop the ketogenic diet combined with a modified Mediterranean diet as a possible tool to improve neuroinflammation in multiple sclerosis.

Microtubule Dynamics and Neuronal Excitability: Advances on Cytoskeletal Components Implicated in Epileptic Phenomena.

Extensive researches have deepened knowledge on the role of synaptic components in epileptogenesis, but limited attention has been devoted to the potential implication of the cytoskeleton. The study of the development of epilepsy and hyperexcitability states involves molecular, synaptic, and structural alterations of neuronal bioelectric activity. In this paper we aim to explore the neurobiological targets involved in microtubule functioning and cytoskeletal transport, i.e. how dynamic scaffolding of microtubules can influence neuronal morphology and excitability, in order to suggest a potential role for microtubule dynamics in the processes turning a normal neuronal network in a hyperexcited one. Pathophysiological alterations of microtubule dynamics inducing neurodegeneration, network remodeling and relative impairment on synaptic transmission were overviewed. Recent researches were reported on the phosphorylation state of microtubule-associated proteins such as tau in neurodegenerative diseases and epileptic states, but also on the effect of microtubule-active agents influencing cytoskeleton destabilization in epilepsy models. The manipulation of microtubule polymerization was found effective in the modulation of hyperexcitability. In addition, it was considered the importance of microtubules and related neurotrophic factors during neural development since they are essential for the formation of a properly functional neuronal network. Otherwise, this can lead to cognitive deficits, hyperexcitability phenomena and neurodevelopmental disorders. Lastly, we evaluated the role of microtubule dynamics on neuronal efficiency considering their importance in the transport of mitochondria, cellular elements fulfilling energy requirements for neuronal activity, and a putative influence on cannabinoid-mediated neuroprotection. This review provides novel perspectives for the implication of microtubule dynamics in the development of epileptic phenomena.

Polybutylene succinate artificial scaffold for peripheral nerve regeneration.

Regeneration and recovery of nerve tissues are a great challenge for medicine, and positively affect the quality of life of patients. The development of tissue engineering offers a new approach to the problem with the creation of multifunctional artificial scaffolds that act on various levels in the damaged tissue, providing physical and biochemical support for the growth of nerve cells. In this study, the effects of the use of a tubular scaffold made of polybutylene succinate (PBS), surgically positioned at the level of a sciatic nerve injured in rat, between the proximal stump and the distal one, was investigated. Scaffolds characterization was carried out by scanning electron microscopy and X-ray microcomputed tomography and magnetic resonance imaging, in vivo. The demonstration of the nerve regeneration was based on the evaluation of electroneurography, measuring the weight of gastrocnemius and tibialis anterior muscles, histological examination of regenerated nerves and observing the recovery of the locomotor activity of animals. The PBS tubular scaffold minimized iatrogenic trauma on the nerve, acting as a directional guide for the regenerating fibers by conveying them toward the distal stump. In this context, neurotrophic and neurotropic factors may accumulate and perform their functions, while invasion by macrophages and scar tissue is hampered.

Correlation of Metabolic Syndrome with Redox Homeostasis Biomarkers: Evidence from High-Fat Diet Model in Wistar Rats.

Metabolic Syndrome (MetS) is an extremely complex disease. A non-balanced diet such as high-fat diet (HFD) induces metabolic dysfunction that could modify redox homeostasis. We here aimed at exploring redox homeostasis in male Wistar rats, following 8 weeks of HFD, correlating the eventual modification of selected biomarkers that could be associated with the clinical manifestations of MetS. Therefore, we selected parameters relative to both the glucose tolerance and lipid altered metabolism, but also oxidative pattern. We assessed some biomarkers of oxidative stress i.e., thiols balance, lipid peroxidation and antioxidant barriers, via the use of specific biochemical assays, individuating eventual cross correlation with parameters relative to MetS through a Principal Component Analysis (PCA). The present study shows that 8 weeks of HFD induce MetS in rats, altering glucose and lipid homeostasis and increasing visceral adipose tissue, but also impairing the physiological antioxidant responses that could not counteract the oxidative stress condition. Crucially, cross-correlation analysis suggested that the assessment of specific oxidative stress parameters reported here can provide information comparable to the more widely acquired biomarkers of Mets such as glucose tolerance. Lastly, hepatic steatosis in association with the oxidative stress condition was also highlighted by histological analysis. This research will elucidate the fundamental impact of these oxidative stress parameters on MetS induced in the HFD rat model, tracing paths for developing prevention approaches.

Modulating Long Term Memory at Late-Encoding Phase: An rTMS Study.

Despite a huge effort of the scientific community, the functioning of Long-Term Memory (LTM) processes is still debated and far from being elucidated. Functional and neurophysiological data point to an involvement of Dorsolateral Prefrontal Cortex (DLPFC) in both encoding and retrieval phases. However, the recently proposed Explicit/Implicit Memory Encoding and Retrieval (EIMER) model proposes that LTM at the encoding phase consists of anatomically and chronologically different sub-phases. On this basis, we aimed to investigate the role of right DLPFC during a late-encoding phase by means of low-frequency rTMS. Thirty right-handed healthy subjects were divided into three experimental groups. Inhibitory rTMS was applied over right-DLPFC immediately after the encoding phase (Late-Encoding Group) or before recognition phase (Pre-Recognition Group), 24 h after, of an LTM task. Both groups also received sham stimulation during the non-target phase, while the third group (Sham Group) received only sham stimulation in both phases. The Late-Encoding Group collected a lower number of correct responses compared with Sham Group (p = 0.00), while Pre-Retrieval Group increased accuracy as compared to the Sham Group (p = 0.0). rTMS-inhibition of the right DLPFC seems able to interfere with LTM memory performances when delivered at a late stage of the encoding phase, with opposite effects at the pre-retrieval phase.

Haptic Perception in Extreme Obesity: qEEG Study Focused on Predictive Coding and Body Schema.

Haptic perception (HP) is a perceptual modality requiring manual exploration to elaborate the physical characteristics of external stimuli through multisensory integrative cortical pathways. Cortical areas exploit processes of predictive coding that collect sensorial inputs to build and update internal perceptual models. Modifications to the internal representation of the body have been associated with eating disorders. In the light of this, obese subjects were selected as a valid experimental model to explore predictive coding in haptic perception. To this purpose, we performed electroencephalographic (EEG) continuous recordings during a haptic task in normally weighted versus obese subjects. EEG power spectra were analyzed in different time intervals. The quality of haptic performance in the obese group was poorer than in control subjects, though exploration times were similar. Spectral analysis showed a significant decrease in theta, alpha and beta frequencies in the right temporo-parietal areas of obese group, whereas gamma bands significantly increased in the left frontal areas. These results suggest that severe obesity could be characterized by an impairment in haptic performances and an altered activation of multisensory integrative cortical areas. These are involved in functional coding of external stimuli, which could interfere with the ability to process a predicted condition.

Through Predictive Personalized Medicine.

Neuroblastoma (NBM) is a deadly form of solid tumor mostly observed in the pediatric age. Although survival rates largely differ depending on host factors and tumor-related features, treatment for clinically aggressive forms of NBM remains challenging. Scientific advances are paving the way to improved and safer therapeutic protocols, and immunotherapy is quickly rising as a promising treatment that is potentially safer and complementary to traditionally adopted surgical procedures, chemotherapy and radiotherapy. Improving therapeutic outcomes requires new approaches to be explored and validated. In-silico predictive models based on analysis of a plethora of data have been proposed by Lombardo et al. as an innovative tool for more efficacious immunotherapy against NBM. In particular, knowledge gained on intracellular signaling pathways linked to the development of NBM was used to predict how the different phenotypes could be modulated to respond to anti-programmed cell death-ligand-1 (PD-L1)/programmed cell death-1 (PD-1) immunotherapy. Prediction or forecasting are important targets of artificial intelligence and machine learning. Hopefully, similar systems could provide a reliable opportunity for a more targeted approach in the near future.

Being in the Past and Perform the Future in a Virtual World: VR Applications to Assess and Enhance Episodic and Prospective Memory in Normal and Pathological Aging.

The process of aging commonly features a gradual deterioration in cognitive performance and, in particular, the decline of memory. Despite the increased longevity of the world's population, the prevalence of neurodegenerative conditions, such as dementia, continues to be a major burden on public health, and consequently, the latest research has been focused on memory and aging. Currently, the failure of episodic and Prospective memory (PM) is one of the main complaints in the elderly, considered among the early symptoms of dementia. It is therefore increasingly important to define more clearly the boundaries between normal and pathological aging. Recently, researchers have begun to build and apply Virtual Environments (VE) to the explicit purpose of better understanding the performance of episodic and PM in complex and realistic contexts, with the perspective of further developing effective training procedures that depend on reliable cognitive assessment methods. Virtual technology offers higher levels of realism than "pen and paper" testing and at the same time more experimental control than naturalistic settings. In this mini-review article, we examine the outcomes of recently available studies on virtual reality technology applications developed for the assessment and improvement of episodic and/or PM. To consider the latest technology, we selected 29 articles that have been published in the last 10 years. These documents show that VR-based technologies can provide a valid basis for screening and treatment and, through increased sensory stimulation and enriched environments reproducing the scenarios of everyday life, could represent effective stimulating experiences even in pathological aging.

Correction to: Cannabinoids, TRPV and nitric oxide: the three ring circus of neuronal excitability.

In the original publication of the article, the names of the authors were incorrectly swapped as Gambino Giuditta · Rizzo Valerio · Giglia Giuseppe · Ferraro Giuseppe · Sardo Pierangelo.

Cannabinoids, TRPV and nitric oxide: the three ring circus of neuronal excitability.

Endocannabinoid system is considered a relevant player in the regulation of neuronal excitability, since it contributes to maintaining the balance of the synaptic ionic milieu. Perturbations to bioelectric conductances have been implicated in the pathophysiological processes leading to hyperexcitability and epileptic seizures. Cannabinoid influence on neurosignalling is exerted on classic receptor-mediated mechanisms or on further molecular targets. Among these, transient receptor potential vanilloid (TRPV) are ionic channels modulated by cannabinoids that are involved in the transduction of a plethora of stimuli and trigger fundamental downstream pathways in the post-synaptic site. In this review, we aim at providing a brief summary of the most recent data about the cross-talk between cannabinoid system and TRPV channels, drawing attention on their role on neuronal hyperexcitability. Then, we aim to unveil a plausible point of interaction between these neural signalling systems taking into consideration nitric oxide, a gaseous molecule inducing profound modifications to neural performances. From this novel perspective, we struggle to propose innovative cellular mechanisms in the regulation of hyperexcitability phenomena, with the goal of exploring plausible CB-related mechanisms underpinning epileptic seizures.

3D Printing Neuron Equivalent Circuits: An Undergraduate Laboratory Exercise.

The electrical equivalent circuit for a neuron is composed of common electrical components in a configuration that replicates the passive electrical properties and behaviors of the neural membrane. It is a powerful tool used to derive such fundamental neurophysiological equations as the Hodgkin-Huxley equations, and it is also the basis for well-known exercises that help students to model the passive (Ohmic) properties of the neuronal membrane. Unfortunately, as these exercises require basic knowledge of electronics, they are generally not physically conducted in biomedical courses, but remain merely conceptual exercises in a book or simulations on a computer. In such manifestations, they lack the "hands-on" appeal for students and teachers afforded by laboratory experimentations. Here, we propose a new approach to these experiments in which a desktop 3D printer and conductive paint are used to build the circuit and the popular programmable microcontroller, the Arduino UNO, is used as a graphical oscilloscope when connected to a standard computer. This set-up has the advantage of being very easy to build and less clumsy than a circuit in a prototyping board or connected with alligator clips, with the added benefit of being conveniently portable for classroom demonstrations. Most importantly, this method allows the monitoring of real-time changes in the current flowing through the circuit by means of a graphical display (by way of the Arduino) at a fraction of the cost of commercially available oscilloscopes.

Brain Distribution and Modulation of Neuronal Excitability by Indicaxanthin From Opuntia Ficus Indica Administered at Nutritionally-Relevant Amounts.

Several studies have recently investigated the role of nutraceuticals in complex pathophysiological processes such as oxidative damages, inflammatory conditions and excitotoxicity. In this regard, the effects of nutraceuticals on basic functions of neuronal cells, such as excitability, are still poorly investigated. For this reason, the possible modulation of neuronal excitability by phytochemicals (PhC) could represent an interesting field of research given that excitotoxicity phenomena are involved in neurodegenerative alterations leading, for example, to Alzheimer's disease. The present study was focused on indicaxanthin from Opuntia ficus indica, a bioactive betalain pigment, with a proven antioxidant and anti-inflammatory potential, previously found to cross blood-brain barrier (BBB) and to modulate the bioelectric activity of hippocampal neurons. On this basis, we aimed at detecting the specific brain areas where indicaxanthin localizes after oral administration at dietary-achievable amounts and highlighting eventual local effects on the excitability of single neuronal units. HPLC analysis of brain tissue 1 h after ingestion of 2 µmol/kg indicaxanthin indicated that the phytochemical accumulates in cortex, hippocampus, diencephalon, brainstem and cerebellum, but not in the striato-pallidal complex. Then, electrophysiological recordings, applying the microiontophoretic technique, were carried out with different amounts of indicaxanthin (0.34, 0.17, 0.085 ng/neuron) to assess whether indicaxanthin influenced the neuronal firing rate. The data showed that the bioelectric activity of neurons belonging to different brain areas was modulated after local injection of indicaxanthin, mainly with dose-related responses. A predominating inhibitory effect was observed, suggesting a possible novel beneficial effect of indicaxanthin in reducing cell excitability. These findings can constitute a new rationale for exploring biological mechanisms through which PhC could modulate neuronal function with a relapse on complex cognitive brain process and related neurodegenerative conditions.