Understanding Functional Neurological Disorder: Recent Insights and Diagnostic Challenges.

Functional neurological disorder (FND), formerly called conversion disorder, is a condition characterized by neurological symptoms that lack an identifiable organic purpose. These signs, which can consist of motor, sensory, or cognitive disturbances, are not deliberately produced and often vary in severity. Its diagnosis is predicated on clinical evaluation and the exclusion of other medical or psychiatric situations. Its treatment typically involves a multidisciplinary technique addressing each of the neurological symptoms and underlying psychological factors via a mixture of medical management, psychotherapy, and supportive interventions. Recent advances in neuroimaging and a deeper exploration of its epidemiology, pathophysiology, and clinical presentation have shed new light on this disorder. This paper synthesizes the current knowledge on FND, focusing on its epidemiology and underlying mechanisms, neuroimaging insights, and the differentiation of FND from feigning or malingering. This review highlights the phenotypic heterogeneity of FND and the diagnostic challenges it presents. It also discusses the significant role of neuroimaging in unraveling the complex neural underpinnings of FND and its potential in predicting treatment response. This paper underscores the importance of a nuanced understanding of FND in informing clinical practice and guiding future research. With advancements in neuroimaging techniques and growing recognition of the disorder's multifaceted nature, the paper suggests a promising trajectory toward more effective, personalized treatment strategies and a better overall understanding of the disorder.

Salt, Not Always a Cardiovascular Enemy? A Mini-Review and Modern Perspective.

Dietary salt intake is a long-debated issue. Increased sodium intake is associated with high blood pressure, leading to salt-sensitive hypertension. Excessive salt intake leads to arterial stiffness in susceptible individuals via impaired nitric oxide action and increased endothelin-1 expression, overactivity of the renal sympathetic nervous system and also via aldosterone-independent activation of the mineralocorticoid receptor. Salt restriction in such individuals reduces blood pressure (BP) values. The optimal level of salt restriction that leads to improved cardiovascular outcomes is still under debate. Current BP and dietary guidelines recommend low sodium intake for the general population. However, a specific category of patients does not develop arterial hypertension in response to sodium loading. In addition, recent research demonstrates the deleterious effects of aggressive sodium restriction, even in heart failure patients. This mini review discusses current literature data regarding the advantages and disadvantages of salt restriction and how it impacts the overall health status.

Oxytocin: Narrative Expert Review of Current Perspectives on the Relationship with Other Neurotransmitters and the Impact on the Main Psychiatric Disorders.

Is a cyclic neuropeptide produced primarily in the hypothalamus and plays an important neuromodulatory role for other neurotransmitter systems, with an impact on behavior, response to danger, stress, and complex social interactions, such as pair bonding and child care. This narrative expert review examines the literature on oxytocin as a brain hormone. We focused on oxytocin structure, distribution, genetics, and the oxytocin receptor system, as well as the relationship of oxytocin with other neurotransmitters and the resulting impacts on the main psychiatric disorders. Oxytocin levels have been correlated over time with mental illness, with numerous studies focusing on oxytocin and the pathophysiology of the main psychiatric disorders, such as autism, schizophrenia, personality disorders, mood, and eating disorders. We highlight the role oxytocin plays in improving symptoms such as anxiety, depression, and social behavior, as the literature suggests. Risk factors and causes for psychiatric disorders range from genetic to environmental and social factors. Oxytocin could impact the latter, being linked with other neurotransmitter systems that are responsible for integrating different situations during the development phases of individuals. Also, these systems have an important role in how the body responds to stressors or bonding with others, helping with the creation of social support groups that could speed up recovery in many situations. Oxytocin has the potential to become a key therapeutic agent for future treatment and prevention strategies concerning the main psychiatric disorders.

Reply to Campbell et al. Comment on "Hogas et al. Salt, Not Always a Cardiovascular Enemy? A Mini-Review and Modern Perspective. Medicina 2022, 58, 1175".

We thank Campbell et al. for their comment [...].

Minireview on the Connections between the Neuropsychiatric and Dental Disorders: Current Perspectives and the Possible Relevance of Oxidative Stress and Other Factors.

Although the connections between neuropsychiatric and dental disorders attracted the attention of some research groups for more than 50 years now, there is a general opinion in the literature that it remains a clearly understudied and underrated topic, with many unknowns and a multitude of challenges for the specialists working in both these areas of research. In this way, considering the previous experience of our groups in these individual matters which are combined here, we are summarizing in this minireport the current status of knowledge on the connections between neuropsychiatric and dental manifestations, as well as some general ideas on how oxidative stress, pain, music therapy or even irritable bowel syndrome-related manifestations could be relevant in this current context and summarize some current approaches in this matter.

Purkinje cells pathology in schizophrenia. A morphometric approach.

OBJECTIVES: Schizophrenia is a brain disorder that affects more than 21 million people worldwide. Ventricle enlargement and reduction in the volume of the temporal lobe overall and in medial temporal structures constitutes the main macroscopic findings, whilst synaptic and spinal changes as well as gliosis in the hippocampal formation, the prefrontal and the entorhinal cortex stand among cardinal microscopic findings in the schizophrenic brains. In recent years, accumulated evidence comes to light about the role of cerebellum in the pathophysiology of schizophrenia. MATERIALS AND METHODS: The present study is based on the morphological analysis and 3D neuronal reconstruction of the Purkinje cells from 10 schizophrenic brains and 10 normal controls. RESULTS: Significant morphological alterations such as loss of distal and terminal dendritic branches and decrease of the density of the dendritic spines constitute the main morphological findings found in the present study. CONCLUSIONS: The present findings may be added to accumulated evidence on macroscopic and microscopic pathology of the cerebellum in schizophrenia. Morphological alterations of Purkinje cells seem to be a central feature of neuropathology of schizophrenia, reflecting to impairment of neuronal connectivity and functionality, and related to motor and cognitive symptoms.

Describing some behavioural animal models of anxiety and their mechanistics with special reference to oxidative stress and oxytocin relevance.

It is now generally accepted that animal studies are playing an important role in the understanding of anxiety disorders, since they contribute to the current knowledge regarding the mechanisms and possible therapeutic approaches in anxiety. In the present review we will detail some essential aspects of behavioral animal models of anxiety related to social defeat paradigm, elevated plus maze, elevated zero or T maze, light/dark box, social interaction test or tests based on predator models, considering the latest theories and methodological approaches in this area of research, as well as our previous studies focusing on anxiety manifestations in a variety of species including rats, zebrafish, dogs and pigs. Moreover, in this context, we will focus on the recent theories concerning oxidative stress, as well as importance of oxytocin administration (especially the intranasal route). This could be important considering that these two factors are currently being investigated as possible mechanisms (oxidative stress status) and related therapeutic target (both intranasal oxytocin and antioxidants) in the pathology of the anxiety disorders.

Age-related dendritic and spinal alterations of pyramidal cells of the human visual cortex.

INTRODUCTION: Normal aging is characterized by deterioration of visual abilities, affecting mainly visual acuity, contrast and wavelength sensitivity. In the present study we attempted to describe the morphological and morphometric alterations of the dendrites and the dendritic spines of the pyramidal cells of the visual cortex during normal aging, in order to approach the visual impairment of aged individuals from a neuropathological point of view. MATERIAL AND METHODS: We studied the visual cortex in 20 brains using the Golgi technique. RESULTS: In pyramidal cells, which represent the majority of cortical neurons, age-related pathology can be observed in cell somata as well as, most importantly, in dendrite number and morphology. The apical dendrites of some pyramidal cells are distorted and tortuous. Horizontal dendritic arborization is also severely decreased. These alterations were more prominent in the corticocortical pyramidal neurons of the 5th layer. CONCLUSIONS: The morphological and morphometric assessment of the dendrites and the dendritic spines in the visual cortex in normal aging revealed substantial alterations of the dendritic arborization and marked loss of the dendritic spines, which may be related to visual impairment even in normal aging.

The oxidative stress hypothesis in Alzheimer's disease.

Oxidative stress may be involved in many somatic and psychiatric pathological states including dementia. The hypothesis of oxidative stress involvement in dementia is supported by much scientific data through biochemical, genetic and molecular studies. Thus, there are many reports of an increased level of the markers for oxidative damage, alterations in the specific activity of the antioxidant system, mutations in specific genes, mitochondrial disturbances and also several connections between oxidative stress and amyloid plaques. Despite these evidence and clinical approaches in using antioxidant therapy in dementia treatment, studies have failed to prove a clear benefit for antioxidant treatment in dementia. Hence, there is a need for further research regarding antioxidant therapy in very early stages of dementia.

The interdependence of the reactive species of oxygen, nitrogen, and carbon

This mini-review tries to summarize the main interdependences between the free radicals of oxygen, nitrogen, and carbon. Also, the main metabolic pathways for these radical species are described, as well as how these affect their interaction and functional implications. Emphasis is made on the metabolic disturbances induced by stressing aggressions that produce radical species. In this way, cellular oxidative imbalances created by the superiority of reactive oxygen species over the antioxidant systems produce both activation of nitroxide synthases and the oxidation of terminal nitrogen from L-arginine, as well as the metabolization of heme until carbon monoxide by nitric oxide-activated hemoxygenase. Also, multiple cellular protein and nucleoprotein alterations determined by these three kinds of radical species are completed by the involvement of hydrogen sulfide, which results from the degradation of L-cysteine by cistationine-ã-lyase. In this way, sufficient experimental data tend to demonstrate the involvement of hydrogen sulfide and other thiol derivatives in the interrelations between oxygen, nitrogen, and carbon, which results in a true radical cascade. Thus, oxidative stress, together with nitrosative and carbonilic stress, may constitute a central point where other factors of vulnerability meet, and their interactions could have an important impact in many modern diseases. Considering that the actions of reactive species can be most of the time corrected, future studies need to establish the therapeutical importance of various agents which modulate oxidative, nitrosative, or carbonilic stress (AU)

The interdependence of the reactive species of oxygen, nitrogen, and carbon.

This mini-review tries to summarize the main interdependences between the free radicals of oxygen, nitrogen, and carbon. Also, the main metabolic pathways for these radical species are described, as well as how these affect their interaction and functional implications. Emphasis is made on the metabolic disturbances induced by stressing aggressions that produce radical species. In this way, cellular oxidative imbalances created by the superiority of reactive oxygen species over the antioxidant systems produce both activation of nitroxide synthases and the oxidation of terminal nitrogen from L-arginine, as well as the metabolization of heme until carbon monoxide by nitric oxide-activated hemoxygenase. Also, multiple cellular protein and nucleoprotein alterations determined by these three kinds of radical species are completed by the involvement of hydrogen sulfide, which results from the degradation of L-cysteine by cistationine-γ-lyase. In this way, sufficient experimental data tend to demonstrate the involvement of hydrogen sulfide and other thiol derivatives in the interrelations between oxygen, nitrogen, and carbon, which results in a true radical cascade. Thus, oxidative stress, together with nitrosative and carbonilic stress, may constitute a central point where other factors of vulnerability meet, and their interactions could have an important impact in many modern diseases. Considering that the actions of reactive species can be most of the time corrected, future studies need to establish the therapeutical importance of various agents which modulate oxidative, nitrosative, or carbonilic stress.

Hippocampal neuronal loss in the CA1 and CA3 areas of Alzheimer's disease patients.

BACKGROUND: It is believed that in Alzheimer's disease (AD) some areas of the brain are particularly vulnerable to specific degenerative processes and that they could exhibit neuronal dysfunction in the earliest stage of the disease. The implications of the hippocampus in memory processes are very well known and it is likely that the hippocampus would be among the first areas of the brain affected by the pathogenic mechanisms occurring in AD. However, the distinction between the neurodegenerative changes that accompany normal ageing and those that characterize AD is not clear. Also, the distribution of the hippocampal cell loss in both normal aging and AD is not very well understood. SUBJECTS AND METHODS: In this context, we focused on the quantification of the neuronal density in the four specific areas of the hippocampus (CA1-CA4) of AD brains, as compared to an age-matched control group, by using the Nissl staining technique. RESULTS: We found a significant reduction of neuronal density especially in the CA1 and CA3 hippocampal areas. The most prominent decrease was found at the CA1 area level, as compared to all other 3 areas which were analyzed. CONCLUSIONS: In the present study we managed to demonstrate and confirm a significant neuronal loss of hippocampus in AD, as compared to an age-matched control group. Moreover, it seems that this decrease of hippocampal neuronal density is more prominent especially at the CA1 and also in the CA3 hippocampal areas. This could have important implications in the design of therapeutic and investigative strategies of AD. However, larger samples are necessary in order to provide the basis for firmer conclusions in this area of research.

The effects of short-term nicotine administration on behavioral and oxidative stress deficiencies induced in a rat model of Parkinson's disease.

BACKGROUND: We previously demonstrated that a 6-hydroxydopamine (6-OHDA) induced lesion of substantia nigra (SN), which is a very well known animal model of Parkinson's disease, resulted in memory deficits and increased brain oxidative stress. Also, recent reports had suggested that nicotine from smoke may contribute, at least in some parts, to the apparent neuroprotective effect of tobacco use in Parkinson's disease. SUBJECTS AND METHODS: In this way, in the present study we were interested to examine the effects of low-dose nicotine administration (5 days, 0.3 mg/kg/day) in a rat model of Parkinson's disease, on behavioral parameters from Y-maze or shuttle-box task and also on the oxidative stress markers from the temporal lobe, which is one of the most vulnerable cortical area to oxidative stress effects. RESULTS: The administration of nicotine resulted in significant improvements of short-term memory, as seen in the Y-maze task, as well an increase of conditioned avoidance responses and decreased number of escape failures in the shuttle-box task. Additionally, an increase in the specific activity of glutathione peroxidase and a decrease of the lipid peroxidation processes is reported. Moreover, we found a significant correlation between the behavioral results from the Y-maze and shuttle-box tasks and the levels of oxidative stress markers. CONCLUSIONS: Taken together our data suggest that short-term administration of low-dose nicotine facilitates memory processes and improves the oxidative stress status of the brain, after a 6-OHDA induced lesion of the SN.

The effects of pergolide on memory and oxidative stress in a rat model of Parkinson’s disease

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One of the most widely used animal models of Parkinson’s disease (PD) involves injecting 6-hydroxydopamine (6-OHDA) directly into the substantia nigra (SN). Some recent reports speculated that dopaminergic drugs may exert brain antioxidant activity, which could explain some of their protective actions. In this way, the aim of the present study was to examine the effects of low-dose pergolide on memory deficits and brain oxidative stress in a 6-OHDA-induced rat model of PD. Right-unilateral lesions of the SN were produced with 6-OHDA. Two weeks after neurosurgery, pergolide (0.3 mg/kg/day) was injected intraperitoneally in the 6-OHDA + pergolide and sham-operated + pergolide groups, while sham-operated and 6-OHDA alone groups received saline. Radial-8-arm maze and Y-maze were used for memory assessment. We also determined some enzymatic antioxidant defenses like superoxide dismutase or glutathione peroxidase and a lipid peroxidation marker [malondialdehyde (MDA)], from the temporal lobe. A reduced number of working/reference memory errors was observed in 6-OHDA + pergolide group, compared to sham-operated rats. Additionally, post hoc analysis showed significant differences between 6-OHDA and 6-OHDA + pergolide groups in both Y-maze and radial-arm-maze tasks. We also noted a significant decrease of MDA level in the 6-OHDA + pergolide group, compared to sham-operated rats. Significant correlations were also found between behavioral parameters and MDA levels. Our data suggest that pergolide facilitates spatial memory and improves brain oxidative balance, after a 6-OHDA-induced model of PD. This could be useful for further investigations and clinical applications of pergolide (AU)

The effects of pergolide on memory and oxidative stress in a rat model of Parkinson's disease.

One of the most widely used animal models of Parkinson's disease (PD) involves injecting 6-hydroxydopamine (6-OHDA) directly into the substantia nigra (SN). Some recent reports speculated that dopaminergic drugs may exert brain antioxidant activity, which could explain some of their protective actions. In this way, the aim of the present study was to examine the effects of low-dose pergolide on memory deficits and brain oxidative stress in a 6-OHDA-induced rat model of PD. Right-unilateral lesions of the SN were produced with 6-OHDA. Two weeks after neurosurgery, pergolide (0.3 mg/kg/day) was injected intraperitoneally in the 6-OHDA + pergolide and sham-operated + pergolide groups, while sham-operated and 6-OHDA alone groups received saline. Radial-8-arm maze and Y-maze were used for memory assessment. We also determined some enzymatic antioxidant defenses like superoxide dismutase or glutathione peroxidase and a lipid peroxidation marker [malondialdehyde (MDA)], from the temporal lobe. A reduced number of working/reference memory errors was observed in 6-OHDA + pergolide group, compared to sham-operated rats. Additionally, post hoc analysis showed significant differences between 6-OHDA and 6-OHDA + pergolide groups in both Y-maze and radial-arm-maze tasks. We also noted a significant decrease of MDA level in the 6-OHDA + pergolide group, compared to sham-operated rats. Significant correlations were also found between behavioral parameters and MDA levels. Our data suggest that pergolide facilitates spatial memory and improves brain oxidative balance, after a 6-OHDA-induced model of PD. This could be useful for further investigations and clinical applications of pergolide.

Cardiovascular risk factors as potential markers for mild cognitive impairment and Alzheimer's disease.

BACKGROUND: Mild cognitive impairment (MCI) is an early stage of cognitive decline that has a significant risk of converting to dementia. Cardiovascular pathology appears to have a major impact in cognitive decline, and it is clear that early identification and correction of cardiovascular morbidity could have a major impact on cognitive functioning. SUBJECTS AND METHODS: Our study was conducted in order to identify some cardiovascular risk factors among patients with cognitive decline (MCI or Alzheimer disease-AD) and to find if there is any correlation with the degree of cognitive decline. We evaluated the body mass index, total cholesterol, hypertension, history of smoking, alcohol consumption and diabetes mellitus in patients with MCI and AD, compared with an age-matched control group. RESULTS: Regarding the body mass index, we observed a progressive decrease in patients with MCI and AD, in comparison with the control group. Similar aspects were also observed in the case of cholesterol levels, only that post hoc analysis revealed no significantly statistical differences between MCI and AD groups. The systolic blood pressure was increased in the patients with MCI and AD. Also, as in the case of cholesterol levels, post hoc analysis revealed no significantly statistical differences between MCI and AD groups. Pearson's correlation showed significant connections between the cardiovascular risk factors and the results of the cognitive evaluation. CONCLUSIONS: Our results constitute additional evidence that cardiovascular risk factors are involved in cognitive regression. This finding could have an important impact on the management of dementia.

Oxidative stress in schizophrenia - focusing on the main markers.

Oxidative stress is the condition arising from imbalance between toxic reactive oxygen species and antioxidant systems. It is believed that increased oxidative stress may be relevant to the pathophysiology of schizophrenia. In this way, the main markers of the lipid peroxidation processes include 4-hydroxynonenal and malondialdehyde. On the other side, the potential toxicity of free radicals is counteracted by a number of cytoprotective antioxidant enzymes that limit the damage, such as superoxide dismutase and glutathione peroxidase. However, the reports regarding the status of oxidative stress markers schizophrenia are very inconsistent, with various authors stating both increased and decreased activities of the main antioxidant enzymes, while others did not observe any significant modifications, as compared to control groups. Similar aspects were also reported in the case of the lipid peroxidation markers, although in here the contradictions are much more reduced than in the case of the antioxidant defences. It is generally believed that the equivocal results mentioned above may be due to different tissues studies, different species or the administrated treatment and the duration of the disease/treatment. In this context, in the present paper we were interested to review some studies regarding the oxidative stress status in patients and animal models of schizophrenia, by referring mainly to antioxidant enzymes and lipid peroxidation markers.

Evaluation of antioxidant enzymes activities and lipid peroxidation in schizophrenic patients treated with typical and atypical antipsychotics.

Studies performed in schizophrenia patients have generally suggested the presence of a compromised antioxidant system, but this is not always consistent with specific observed parameters, which on the whole, show evidences of dysregulation. There are also controversies regarding the oxidative stress status in patients treated with typical vs. atypical antipsychotics. In this context, the aim of the present work was to evaluate the specific activity of some peripheral antioxidant defences like superoxide dismutase (SOD) and glutathione peroxidase (GPX) and the level of a lipid peroxidation maker (malondialdehyde-MDA), in schizophrenic patients treated with typical (haloperidol) or atypical (olanzapine, quetiapine and risperidone) antipsychotics, compared with age-matched healthy subjects. We found a significant decrease in GPX specific activity and also a significant increase of MDA levels in schizophrenic patients, compared to age-matched control group, regardless of their type of treatment. Additionally, an increase in SOD specific activity was observed, mainly in the patients treated with haloperidol and quetiapine. Further research is necessary in order to elucidate the effects of different antipsychotic agents on antioxidant enzymes and lipid peroxidation or possible interventions at the oxidative stress level in schizophrenic patients.

Changes of some oxidative stress markers in the serum of patients with mild cognitive impairment and Alzheimer's disease.

Mild cognitive impairment (MCI) is a nosological entity proposed as an intermediate state between normal aging and dementia. MCI seems to represent an early stage of Alzheimer's disease (AD) and there is a great interest in the relationship between MCI and the progression to AD. Some studies have demonstrated an accumulation of products of free radical damage in the central nervous system and in the peripheral tissues of subjects with AD or mild cognitive impairment. The aim of the present work was to evaluate the serum levels of some enzymatic antioxidant defences like superoxide dismutase (SOD) and glutathione peroxidase (GPX), as well as lipid peroxidation markers like MDA (malondialdehyde), in MCI and AD patients, compared with age-matched healthy controls. The subjects of this study (45 patients) consisted of 15 individuals with mild cognitive impairment (MCI), 15 with Alzheimer's disease (AD) and 15 healthy age-matched controls. Biochemical analyses showed a similar decrease of the main enzymatic antioxidant defences (SOD and GPX) and increased production of lipid peroxidation marker (MDA) in the serum of the MCI and AD patients, compared to age-matched control group. This study clearly demonstrates that oxidative stress damage occurs in patients with MCI and AD. Moreover, some enzymatic markers of oxidative stress are similar in MCI and AD patients, suggesting that oxidative damage could be one important aspect for the onset of AD.