Olfactory dysfunction and its related molecular mechanisms in Parkinson’s disease

Changes in olfactory function are considered to be early biomarkers of Parkinson’s disease.Olfactory dysfunction is one of the earliest non-motor features of Parkinson’s disease,appearing in about 90%of patients with early-stage Parkinson’s disease,and can often predate the diagnosis by years.Therefore,olfactory dysfunction should be considered a reliable marker of the disease.However,the mechanisms responsible for olfactory dysfunction are currently unknown.In this article,we clearly explain the pathology and medical definition of olfactory function as a biomarker for early-stage Parkinson’s disease.On the basis of the findings of clinical olfactory function tests and animal model experiments as well as neurotransmitter expression levels,we further characterize the relationship between olfactory dysfunction and neurodegenerative diseases as well as the molecular mechanisms underlying olfactory dysfunction in the pathology of early-stage Parkinson’s disease.The findings highlighted in this review suggest that olfactory dysfunction is an important biomarker for preclinical-stage Parkinson’s disease.Therefore,therapeutic drugs targeting non-motor symptoms such as olfactory dysfunction in the early stage of Parkinson’s disease may prevent or delay dopaminergic neurodegeneration and reduce motor symptoms,highlighting the potential of identifying effective targets for treating Parkinson’s disease by inhibiting the deterioration of olfactory dysfunction.

A review of the neurotransmitter system associated with cognitive function of the cerebellum in Parkinson's disease

The dichotomized brain system is a concept that was generalized from the‘dual syndrome hypothesis’to explain the heterogeneity of cognitive impairment,in which anterior and posterior brain systems are independent but partially overlap.The dopaminergic system acts on the anterior brain and is responsible for executive function,working memory,and planning.In contrast,the cholinergic system acts on the posterior brain and is responsible for semantic fluency and visuospatial function.Evidence from dopaminergic/cholinergic imaging or functional neuroimaging has shed significant insight relating to the involvement of the cerebellum in the cognitive process of patients with Parkinson’s disease.Previous research has reported evidence that the cerebellum receives both dopaminergic and cholinergic projections.However,whether these two neurotransmitter systems are associated with cognitive function has yet to be fully elucidated.Furthermore,the precise role of the cerebellum in patients with Parkinson’s disease and cognitive impairment remains unclear.Therefore,in this review,we summarize the cerebellar dopaminergic and cholinergic projections and their relationships with cognition,as reported by previous studies,and investigated the role of the cerebellum in patients with Parkinson’s disease and cognitive impairment,as determined by functional neuroimaging.Our findings will help us to understand the role of the cerebellum in the mechanisms underlying cognitive impairment in Parkinson’s disease.

Effects of a Cocktail Supplement of Ginkgo Biloba and Acai Extract on Cognitive Symptoms of Parkinson’s Disease

Parkinson’s Disease (PD) is a neurodegenerative disorder characterized by motor and non-motor symptoms, including cognitive impairment. Current treatments often involve synthetic drugs with significant side effects and potential for dependency. This study investigates the effects of a natural supplement combination of Ginkgo Biloba and Acai Extract on cognitive symptoms in a 77-year-old male with PD. The participant underwent a three-month supplementation regimen, with cognitive function assessed using the Montreal Cognitive Assessment (MoCA) test before and after the intervention. The results indicated an improvement in cognitive scores, suggesting that the combination of Ginkgo Biloba and Acai Extract may offer a promising alternative or adjunct to conventional PD treatments. This study highlights the potential of natural supplements in managing PD symptoms and calls for further research with larger sample sizes to confirm these findings. Human data was performed in accordance with the Declaration of Helsinki by the Roxbury District IRB Board (IRB Number: IRB00011767).

Gut microbiota-astrocyte axis: new insights into age-related cognitive decline

With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent worldwide.Aging is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota,microbial metabolites,and the functions of astrocytes.The microbiota–gut–brain axis has been the focus of multiple studies and is closely associated with cognitive function.This article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative diseases.This article also summarizes the gut microbiota components that affect astrocyte function,mainly through the vagus nerve,immune responses,circadian rhythms,and microbial metabolites.Finally,this article summarizes the mechanism by which the gut microbiota–astrocyte axis plays a role in Alzheimer’s and Parkinson’s diseases.Our findings have revealed the critical role of the microbiota–astrocyte axis in age-related cognitive decline,aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition.

Possible role of glial cell line-derived neurotrophic factor for predicting cognitive impairment in Parkinson’s disease:a case-control study

Glial cell line-derived neurotrophic factor(GDNF)plays an important role in the protection of dopaminergic neurons,but there are few reports of the relationship between GDNF and its precursors(α-pro-GDNF andβ-pro-GDNF)and cognitive impairment in Parkinson’s disease.This study aimed to investigate the relationship between the serum levels of GDNF and its precursors and cognitive impairment in Parkinson’s disease,and to assess their potential as a diagnostic marker.Fifty-three primary outpatients and hospitalized patients with Parkinson’s disease(23 men and 30 women)with an average age of 66.58 years were enrolled from the Affiliated Hospital of Xuzhou Medical University of China in this case-control study.The patients were divided into the Parkinson’s disease with cognitive impairment group(n=27)and the Parkinson’s disease with normal cognitive function group(n=26)based on their Mini-Mental State Examination,Montreal Cognitive Assessment,and Clinical Dementia Rating scores.In addition,26 age-and sex-matched healthy subjects were included as the healthy control group.Results demonstrated that serum GDNF levels were significantly higher in the Parkinson’s disease with normal cognitive function group than in the other two groups.There were no significant differences in GDNF precursor levels among the three groups.Correlation analysis revealed that serum GDNF levels,GDNF/α-pro-GDNF ratios,and GDNF/β-pro-GDNF ratios were moderately or highly correlated with the Mini-Mental State Examination,Montreal Cognitive Assessment,and Clinical Dementia Rating scores.To explore the risk factors for cognitive impairment in patients with Parkinson’s disease,logistic regression analysis and stepwise linear regression analysis were performed.Both GDNF levels and Hoehn-Yahr stage were risk factors for cognitive impairment in Parkinson’s disease,and were the common influencing factors for cognitive scale scores.Neitherα-pro-GDNF norβ-pro-GDNF was risk factors for cognitive impairment in Parkinson’s disease.A receiver operating characteristic curve of GDNF was generated to predict cognitive function in Parkinson’s disease(area under the curve=0.859).This result indicates that the possibility that serum GDNF can correctly distinguish whether patients with Parkinson’s disease have cognitive impairment is 0.859.Together,these results suggest that serum GDNF may be an effective diagnostic marker for cognitive impairment in Parkinson’s disease.However,α-pro-GDNF andβ-pro-GDNF are not useful for predicting cognitive impairment in this disease.This study was approved by Ethics Committee of the Affiliated Hospital of Xuzhou Medical University,China(approval No.XYFY2017-KL047-01)on November 30,2017.

Blunt dopamine transmission due to decreased GDNF in the PFC evokes cognitive impairment in Parkinson’s disease

Studies have found that the absence of glial cell line-derived neurotrophic factor may be the primary risk factor for Parkinson’s disease. However, there have not been any studies conducted on the potential relationship between glial cell line-derived neurotrophic factor and cognitive performance in Parkinson’s disease. We first performed a retrospective case-control study at the Affiliated Hospital of Xuzhou Medical University between September 2018 and January 2020 and found that a decreased serum level of glial cell line-derived neurotrophic factor was a risk factor for cognitive disorders in patients with Parkinson’s disease. We then established a mouse model of Parkinson’s disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and analyzed the potential relationships among glial cell line-derived neurotrophic factor in the prefrontal cortex, dopamine transmission, and cognitive function. Our results showed that decreased glial cell line-derived neurotrophic factor in the prefrontal cortex weakened dopamine release and transmission by upregulating the presynaptic membrane expression of the dopamine transporter, which led to the loss and primitivization of dendritic spines of pyramidal neurons and cognitive impairment. In addition, magnetic resonance imaging data showed that the long-term lack of glial cell line-derived neurotrophic factor reduced the connectivity between the prefrontal cortex and other brain regions, and exogenous glial cell line-derived neurotrophic factor significantly improved this connectivity. These findings suggested that decreased glial cell line-derived neurotrophic factor in the prefrontal cortex leads to neuroplastic degeneration at the level of synaptic connections and circuits, which results in cognitive impairment in patients with Parkinson’s disease.

Efficacy of cognitive rehabilitation in Parkinson's disease

Cognitive rehabilitation is a potential and promising treatment for cognitive impairment in Parkinson＇s disease （PD） that has shown efficacy in diverse studies. In addition, some few studies have found brain changes after cognitive rehabilitation in PD, which supports the existence of brain plasticity associated to cognitive training in a degen- erative disease.

Virtual Cognitive Screenings and Interviews of Patients with Neurodegenerative Conditions Associated with Alzheimer’s Disease and Parkinson’s Disease

The current pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), commonly referred to as COVID-19, brings myriad challenges to research conducted among those more susceptible to the virus. According to the United States (US) Centers for Disease Control (CDC), eight out of ten re-ported COVID-19 deaths are among people > 65 years of age and older. Nonetheless, researchers must continue the crucial work of investigating and understanding diseases that affect the elderly. The focus of this white paper is to assess the challenges associated with research within the elderly population with neurocognitive conditions. Specifically, this paper addresses the need for the standardized administration of performance measures (e.g., neurocognitive assessments) among a dementia population while ensuring the physical safety of participants. Consideration is given to the administration of performance measures and the availability and feasibility of administering these measures remotely to a population that may have difficulty using novel technologies. In implementing remote research assessments, it is suggested that researchers fol-low a GAMMA approach by: 1) establishing clear Guidance on remote visit expectations and processes;2) establishing Appropriate exclusionary criteria in the development of the study design;3) providing subjects Appropriate study Materials for visual processing;4) incorporating Multiple data sources in the overall study design (e.g., caregiver input);and 5) Acknowledging that there will be study limitations as researchers use emerging technology with this patient population, and using mitigation strategies for these limitations where possible.

Levodopa/Carbidopa Intestinal Gel for Treatment of Advanced Parkinson’s Disease: An Update on the Effects of Cognitive Functions

Cognitive impairment is a frequent non-motorsymptom of Parkinson’s disease (PD). In early disease stage, this takes the features of dysexecutive syndrome, and is mostly dependent on derangement of frontostriatal circuitries. In advanced stages, worsening of dysexecutive symptoms is accompanied by disorientation and memory deficit leading to dementia in 30% of cases, due to multiple neurotransmitter derangement. Dysexecutive symptoms in the early stages of PD may benefit from dopamine replacement therapy (DRT). Conversely, severe cognitive symptoms in more advanced stages are frequently aggravated by DRT. In particular, pulsatile stimulation of dopaminergic receptors by orally administered levodopa (LD) plays a significant negative role on cognitive and neuropsychiatric symptoms in advanced PD. The introduction of a gel of LD-carbidopa for continuous intestinal administration (LCIG) allows marked stabilization of plasma LD concentrations and provides benefit on motor fluctuations and dyskinesia of significantly greater magnitude than conventional oral administration in advanced PD patients. The results from several preliminary studies suggest that efficacy of LCGI on motor symptoms may be accompanied by good tolerability and potential benefit on several non-motor symptoms, including cognitive impairment. Future studies with longer observation period and larger cohorts are advised to confirm these preliminary observations.

Low Frequency of Leisure-Time Activities Correlates with Cognitive Decline and Apathy in Patients with Parkinson’s Disease

Objective: The purpose of this study is to investigate habitual leisure-time activities (physical and non-physical leisure activities) in patients with Parkinson’s disease (PD), and to determine any potential benefits of these activities on cognitive functions and emotional symptoms. Methods: Thirty-two patients with PD and 25 demographically-matched healthy controls participated in the present study. Neuropsychological tests (Wisconsin Card Sorting Test, Trail Making Test, Digit Span Test, Verbal Fluency Test, and Japanese Verbal Learning Test), assessment of emotional sym- ptoms, and interviews for confirmation of habitual leisure-time activities were conducted for all participants. Results: Patients with PD significantly showed the lower frequency of both physical and non-physical leisure activities than healthy controls. Compared to patients who engaged in physical leisure activities, patients who did not engage in such activities performed worse on the Trail Making Test (TMT-B, and TMT-B minus A). Moreover, patients who engaged in non-physical leisure activities were less apathetic than patients who did not engage in such activities. Conclusions: Our preliminary study shows that habitual leisure-time activities correlate with cognitive function and emotions in patients with PD. Reducing sedentary lifestyles and promoting habitual leisure-time activities may be helpful for preventing cognitive decline and apathy.

The pathogenesis of Parkinson’s disease and crosstalk with other diseases

In China,Parkinson’s disease(PD)is the second most prevalent central nervous system(CNS)degenerative illness affecting middle-aged and older persons.Movement disorders including resting tremor,bradykinesia,myotonia,postural instability,and gait instability are the predominant clinical symptoms.The two main types of PD are sporadic and familial,with sporadic PD being the more prevalent of the two.The environment,genetics,mitochondrial dysfunction,oxidative stress,inflammation,protein aggregation and misfolding,loss of trophic factors,cell death,and gut microbiota may all have a role in the etiology of PD.PD is inversely connected with other cancers and positively correlated with COVID-19,diabetes mellitus(DM),melanoma,and ischemic heart disease(IHD)risk.Delaying disease progression,managing motor and non-motor symptoms,and avoiding and controlling dysfunction in the middle and later phases of the disease are the key areas of research and development for its therapy.Presently,the development and progression of PD can be slowed down by using conventional pharmacology,natural items,and innovative technology.This article reviews the pathogenesis of PD,its correlations with other non-genetic diseases,and the research progress of drugs and technologies for alleviating PD.

Transcranial Direct Current Stimulation: Effects on Motor and Non-Motor Symptoms of Parkinson’s Disease

Introduction: In the last thirty years, brain neuromodulation techniques have been used as an alternative to pharmacological treatment of neurological disorders. Parkinson’s disease (PD) is a neurodegenerative disorder leading to bradykinesia, rest tremor, postural changes, and non-motor symptoms such as depression, anxiety, sleep disorders, pain, and cognitive decline that compromises executive functions (EFs), responsible for the orderly execution of behaviors and tasks of daily life and intentional and directed actions. To this date, a few studies with transcranial direct current stimulation (tDCS) have shown beneficial effects in PD patients concerning specific motor and non-motor symptoms, targeting the motor cortex and/or prefrontal regions. Objective: The main objective of this study was to evaluate the effects of left prefrontal tDCS across a broad spectrum of motor and non-motor symptoms of PD using established validated scales. Method: Single-blind randomized clinical trial with 18 volunteers with PD, aged between 45 and 80 years (66.1 ± 9.65), who met inclusion and exclusion criteria. Participants were submitted to assessments of motor and non-motor functions employing psychometric scales and tests to evaluate EFs and were randomly divided into two groups: control (sham stimulation) and experimental (active stimulation). All participants were involved in three separate tDCS sessions. The anode was positioned over the left dorsolateral prefrontal cortex and the cathode over the right supraorbital region, with a direct current intensity of 2 mA, lasting 20 minutes. At the end of the three sessions, all participants were reassessed. Results: Significant effects of tDCS on non-motor functions were observed for cognition (verbal fluency of actions, clock copy test, appointment by visual confrontation, and verbal memory with immediate free recall) and subjective assessment of sleep quality (overall restlessness and discomfort in the arms and legs at night, leg and arm cramps at night and distressing dreams). There was also an improvement in the rate of errors and successes for congruent and incongruent stimuli of the Stroop Test. The beneficial effects on motor function were decreased rigidity, improved gait, and greater agility in the finger-tapping test. Conclusion: Three tDCS sessions showed positive results for participants with PD, producing significant improvements in various motor and non-motor functions, including sleep quality, cognition, and EFs. Additionally, the present results indicate that tDCS neuromodulation of the left dorsolateral prefrontal cortex region is feasible, safe, and provides significant objective benefits for PD patients.

Protective mechanism of testosterone on cognitive impairment in a rat model of Alzheimer's disease

Cognitive dysfunction in Alzheimer's disease is strongly associated with a reduction in synaptic plasticity, which may be induced by oxidative stress. Testosterone is beneficial in learning and memory, although the underlying protective mechanism of testosterone on cognitive performance remains unclear. This study explored the protective mechanism of a subcutaneous injection of 0.75 mg testosterone on cognitive dysfunction induced by bilateral injections of amyloid beta 1–42 oligomers into the lateral ventricles of male rats. Morris water maze test results demonstrated that testosterone treatment remarkably reduced escape latency and path length in Alzheimer's disease rat models. During probe trials, testosterone administration significantly elevated the percentage of time spent in the target quadrant and the number of platform crossings. However, flutamide, an androgen receptor antagonist, inhibited the protective effect of testosterone on cognitive performance in Alzheimer's disease rat models. Nissl staining, immunohistochemistry, western blot assay, and enzyme-linked immunosorbent assay results showed that the number of intact hippocampal pyramidal cells, the dendritic spine density in the hippocampal CA1 region, the immune response and expression level of postsynaptic density protein 95 in the hippocampus, and the activities of superoxide dismutase and glutathione peroxidase were increased with testosterone treatment. In contrast, testosterone treatment reduced malondialdehyde levels. Flutamide inhibited the effects of testosterone on all of these indicators. Our data showed that the protective effect of testosterone on cognitive dysfunction in Alzheimer's disease is mediated via androgen receptors to scavenge free radicals, thereby enhancing synaptic plasticity.

The Cardiovascular and Cerebrovascular Effects on Cognition in Persons with Parkinson’s Disease: A Systematic Review of the Literature

Purpose: The purpose of this systematic review of the literature is to examine the cerebrovascular and cardiovascular effects on cognition in persons with Parkinson’s disease. Relevance: Physical therapy treatment of persons with Parkinson’s disease (PD) has traditionally focused on lessening the impact of disease severity by improving quality of life and functional capacity. Research has shown that quality of life in persons with PD is not only significantly affected by motor symptoms, but also by the presence of defined non-motor symptoms such as cerebrovascular perfusion, cardiovascular dysfunction, and cognitive impairment. This study seeks to determine a causative effect among these non-motor symptoms with the intention to better manage cognitive impairment in persons with PD. Methods: A literature search was conducted utilizing the following databases: Scopus, PubMed, and CINAHL. After evaluating and grading studies using the Downs and Black Checklist, a total of seven studies remained for the final review. Results: Five common domains of cognition emerged throughout the seven studies: executive function, attention, verbal memory and fluency, visual memory, and working memory. Considering the articles reviewed, a relationship between cerebrovascular and cardiovascular deficiency and cognitive impairment in persons with PD was established. Conclusions: Persons with PD and certain cerebrovascular and cardiovascular risk factors, including orthostatic hypotension and systemic hypertension, should be referred to appropriate professionals for comprehensive neuropsychological testing secondary to an increased risk for more severe cognitive deficit.

Cognitive training for elderly patients with early Alzheimer’s disease in the Qinghai-Tibet Plateau: A pilot study

BACKGROUND Alzheimer’s disease(AD)influences the social and economic quality of life of older adult patients and their families.AIM To explore the efficacy of cognitive training in clinical nursing for patients with early AD residing in the plateau area.METHODS This pilot study was conducted in patients with early AD treated in the Geriatric Department of the Qinghai Provincial People’s Hospital between August 2019 and March 2021.The patients were divided into a cognitive training group and a conventional nursing group using the random number table method.Patients in the conventional nursing group received conventional nursing,whereas the patients in the cognitive training group received the new nursing intervention.The mini-mental state examination(MMSE)and activities of daily living(ADL)scales were used to compare the cognitive ability and daily activities,respectively,between the two groups before and after the intervention.RESULTS Sixty patients were enrolled in this study,with 30 patients in the cognitive training group and conventional nursing group,respectively.The MMSE and ADL scores were significantly higher in the cognitive training group than in the conventional nursing group after the intervention(MMSE:25.11±2.02 vs 22.26±1.23,P=0.032;ADL:68.72±4.86 vs 60.16±2.27,P=0.018).CONCLUSION The application of cognitive training in clinical nursing for patients with early AD could improve both their cognitive ability and ADL.This method could be applied in clinical practice to manage cognitive dysfunction in patients with early AD.

Impact of cognition-related single nucleotide polymorphisms on brain imaging phenotype in Parkinson’s disease

Multiple single nucleotide polymorphisms may contribute to cognitive decline in Parkinson’s disease. However, the mechanism by which these single nucleotide polymorphisms modify brain imaging phenotype remains unclear. The aim of this study was to investigate the potential effects of multiple single nucleotide polymorphisms on brain imaging phenotype in Parkinson’s disease. Forty-eight Parkinson’s disease patients and 39 matched healthy controls underwent genotyping and 7 T magnetic resonance imaging. A cognitive-weighted polygenic risk score model was designed, in which the effect sizes were determined individually for 36 single nucleotide polymorphisms. The correlations between polygenic risk score, neuroimaging features, and clinical data were analyzed. Furthermore, individual single nucleotide polymorphism analysis was performed to explore the main effects of genotypes and their interactive effects with Parkinson’s disease diagnosis. We found that, in Parkinson’s disease, the polygenic risk score was correlated with the neural activity of the hippocampus, parahippocampus, and fusiform gyrus, and with hippocampal-prefrontal and fusiform-temporal connectivity, as well as with gray matter alterations in the orbitofrontal cortex. In addition, we found that single nucleotide polymorphisms in α-synuclein(SNCA) were associated with white matter microstructural changes in the superior corona radiata, corpus callosum, and external capsule. A single nucleotide polymorphism in catechol-O-methyltransferase was associated with the neural activities of the lingual, fusiform, and occipital gyri, which are involved in visual cognitive dysfunction. Furthermore, DRD3 was associated with frontal and temporal lobe function and structure. In conclusion, imaging genetics is useful for providing a better understanding of the genetic pathways involved in the pathophysiologic processes underlying Parkinson’s disease. This study provides evidence of an association between genetic factors, cognitive functions, and multi-modality neuroimaging biomarkers in Parkinson’s disease.

Effects of Cholinesterase Inhibitors in Cognition on Parkinson’s Disease Dementia: A Systematic Review and Meta-Analysis

Introduction: Dementia is frequently associated with Parkinson’s disease, especially in later stages. Efficacy of cholinesterase inhibitors (ChI) in Alzheimer’s dementia is well established. However, treatment with ChI in Parkinson’s disease dementia (PDD) remains controversial. The objective of this systematic review and meta-analysis was to assess the effects of ChI in PDD. Methods: A comprehensive literature search was performed in MEDLINE, EMBASE and Cochrane library up to March 2014 using the descriptors “Parkinson’s disease”, “dementia in Parkinson’s disease”, “cognition”, “acetylcholinesterase inhibitors”, “cholinesterase inhibitors”, “anticholinesterase agents”, “rivastigmine”, “donepezil” and “galantamine” (Pubmed search strategy). All randomized, doubleblinded, placebo-controlled trials that met the eligibility criteria and assessed the effects of ChI in PDD were considered for analysis. There were no restrictions regarding paper language. Summary effect-sizes were presented as standardized mean differences (SMD) and the pooled analysis was performed with a fixed-effects model. Outcomes considered for analysis were the Mini Mental Status Exam (MMSE) score and the cognition scale for evaluation of dementia ADAS-Cog. The degree of heterogeneity between included studies was assessed through the I2 test. Results: After a comprehensive search, 175 references were retrieved. From these, five randomized trials involving 946PDD subjects were included in the review. Four studies used donepezil and only one study used rivastigmine. The pooled analysis of five studies that assessed the effects of ChI in MMSE total score showed a SMD of 0.24 (CI 95% 0.11 - 0.38). Three studies considered the effects of ChI on Adas-Cog and the pooled results showed a SMD of 0.21 (CI 95% 0.07 - 0.35). There was no significant heterogeneity between the studies. Conclusions: The results of this systematic review and meta- analysis suggest that ChI improves cognitive impairment in PDD subjects. Despite statistically significant, the translation of these results into relevant clinical improvement should be taken with caution, as the studies did not address what would be considered a clinically significant result.

NADPH oxidase 4(NOX4)as a biomarker and therapeutic target in neurodegenerative diseases

Diseases like Alzheimer’s and Parkinson’s diseases are defined by inflammation and the damage neurons undergo due to oxidative stress. A primary reactive oxygen species contributor in the central nervous system, NADPH oxidase 4, is viewed as a potential therapeutic touchstone and indicative marker for these ailments. This in-depth review brings to light distinct features of NADPH oxidase 4, responsible for generating superoxide and hydrogen peroxide, emphasizing its pivotal role in activating glial cells, inciting inflammation, and disturbing neuronal functions. Significantly, malfunctioning astrocytes, forming the majority in the central nervous system, play a part in advancing neurodegenerative diseases, due to their reactive oxygen species and inflammatory factor secretion. Our study reveals that aiming at NADPH oxidase 4 within astrocytes could be a viable treatment pathway to reduce oxidative damage and halt neurodegenerative processes. Adjusting NADPH oxidase 4 activity might influence the neuroinflammatory cytokine levels, including myeloperoxidase and osteopontin, offering better prospects for conditions like Alzheimer’s disease and Parkinson’s disease. This review sheds light on the role of NADPH oxidase 4 in neural degeneration, emphasizing its drug target potential, and paving the path for novel treatment approaches to combat these severe conditions.

Exploring the Association between Oral Microbiome and Mild Cognitive Impairment: A Narrative Review

Objective: Some studies have investigated the association between oral microbiome and mild cognitive impairment (MCI). However, there needs to be more narrative reviews synthesizing this evidence. This study aimed to bridge this gap in the current knowledge. Methods: A comprehensive search was conducted on PubMed (MEDLINE) to identify studies examining the association between the oral microbiome and MCI. Search parameters and inclusion criteria were clearly defined, encompassing terms related to the oral microbiome, MCI, and their association. Two authors independently selected relevant studies and performed data extraction. Result: Four studies were included. Two cohort studies and two case-control reported an association between the oral microbiome and MCI. Conclusion: Based on the evidence synthesized from the included studies, the review suggests an association between MCI and the oral microbiome. Specifically, all included studies identified significant differences in the abundance of specific microbial species between individuals with MCI and those with normal cognitive function, underscoring the potential role of these species in neuroinflammatory diseases.

A novel method for evaluating brain function and microstructural changes in Parkinson's disease

In this study,microstructural brain damage in Parkinson＇s disease patients was examined using diffusion tensor imaging and tract-based spatial statistics.The analyses revealed the presence of neuronal damage in the substantia nigra and putamen in the Parkinson＇s disease patients.Moreover,disease symptoms worsened with increasing damage to the substantia nigra,confirming that the substantia nigra and basal ganglia are the main structures affected in Parkinson＇s disease.We also found that microstructural damage to the putamen,caudate nucleus and frontal lobe positively correlated with depression.Based on the tract-based spatial statistics,various white matter tracts appeared to have microstructural damage,and this correlated with cognitive disorder and depression.Taken together,our results suggest that diffusion tensor imaging and tract-based spatial statistics can be used to effectively study brain function and microstructural changes in patients with Parkinson＇s disease.Our novel findings should contribute to our understanding of the histopathological basis of cognitive dysfunction and depression in Parkinson＇s disease.