Effects of neuroinflammation on the regenerative capacity of brain stem cells

FDA-approved cannabidiol [Epidiolex®] alleviates Gulf War Illness-linked cognitive and mood dysfunction, hyperalgesia, neuroinflammatory signaling, and declined neurogenesis

BACKGROUND

Chronic Gulf War Illness (GWI) is characterized by cognitive and mood impairments, as well as persistent neuroinflammation and oxidative stress. This study aimed to investigate the efficacy of Epidiolex®, a Food and Drug Administration (FDA)-approved cannabidiol (CBD), in improving brain function in a rat model of chronic GWI.

METHODS

Six months after exposure to low doses of GWI-related chemicals [pyridostigmine bromide, N,N-diethyl-meta-toluamide (DEET), and permethrin (PER)] along with moderate stress, rats with chronic GWI were administered either vehicle (VEH) or CBD (20 mg/kg, oral) for 16 weeks. Neurobehavioral tests were conducted on 11 weeks after treatment initiation to evaluate the performance of rats in tasks related to associative recognition memory, object location memory, pattern separation, and sucrose preference. The effect of CBD on hyperalgesia was also examined. The brain tissues were processed for immunohistochemical and molecular studies following behavioral tests.

RESULTS

GWI rats treated with VEH exhibited impairments in all cognitive tasks and anhedonia, whereas CBD-treated GWI rats showed improvements in all cognitive tasks and no anhedonia. Additionally, CBD treatment alleviated hyperalgesia in GWI rats. Analysis of hippocampal tissues from VEH-treated rats revealed astrocyte hypertrophy and increased percentages of activated microglia presenting NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) complexes as well as elevated levels of proteins involved in NLRP3 inflammasome activation and Janus kinase/signal transducers and activators of the transcription (JAK/STAT) signaling. Furthermore, there were increased concentrations of proinflammatory and oxidative stress markers along with decreased neurogenesis. In contrast, the hippocampus from CBD-treated GWI rats displayed reduced levels of proteins mediating the activation of NLRP3 inflammasomes and JAK/STAT signaling, normalized concentrations of proinflammatory cytokines and oxidative stress markers, and improved neurogenesis. Notably, CBD treatment did not alter the concentration of endogenous cannabinoid anandamide in the hippocampus.

CONCLUSIONS

The use of an FDA-approved CBD (Epidiolex®) has been shown to effectively alleviate cognitive and mood impairments as well as hyperalgesia associated with chronic GWI. Importantly, the improvements observed in rats with chronic GWI in this study were attributed to the ability of CBD to significantly suppress signaling pathways that perpetuate chronic neuroinflammation.

The relation between MIND diet with odds of attention-deficit/hyperactivity disorder in Iranian children: a case-control study

This study aims to investigate the association between the MIND index (Mediterranean- Dietary approaches to Stop Hypertension diet Intervention for Neurodegenerative Delay) and attention-deficit hyperactivity disorder (ADHD) in the Iranian children. It builds upon existing research that highlights the role of dietary antioxidants in alleviating psychological disorders, cognitive impairments, and memory deficits. Additionally, previous studies have separately explored the beneficial effects of the Mediterranean and DASH diets on these issues. A case-control study was undertaken in Iran, involving a sample of 360 children and adolescents aged 7-13 years. Participants were divided into two groups, namely the case group (n = 120) and the control group (n = 240), with age and sex being matched between the groups. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV-TR) was employed for the diagnosis of ADHD. The MIND diet score was computed using the food intake data acquired from the Food Frequency Questionnaire (FFQ) completed by the subjects. The mean ± SD for the age and BMI of the study population was 8.76 ± 1.64 years and 16.90 ± 3.58 kg/m2, respectively. The mean score of MIND in this study was 27.93. After adjustment for potential confounder in the final model, subjects in highest compared to the lowest quartile of MIND diet score had significantly lower odds of ADHD (OR = 0.59, 95% CI 0.37-0.83; P-trend = 0.019). This study provides valuable evidence suggesting that adherence to the MIND diet is associated with decreased odds of ADHD.

Harnessing the Stem Cell Niche in Regenerative Medicine: Innovative Avenue to Combat Neurodegenerative Diseases

Regenerative medicine harnesses the body's innate capacity for self-repair to restore malfunctioning tissues and organs. Stem cell therapies represent a key regenerative strategy, but to effectively harness their potential necessitates a nuanced understanding of the stem cell niche. This specialized microenvironment regulates critical stem cell behaviors including quiescence, activation, differentiation, and homing. Emerging research reveals that dysfunction within endogenous neural stem cell niches contributes to neurodegenerative pathologies and impedes regeneration. Strategies such as modifying signaling pathways, or epigenetic interventions to restore niche homeostasis and signaling, hold promise for revitalizing neurogenesis and neural repair in diseases like Alzheimer's and Parkinson's. Comparative studies of highly regenerative species provide evolutionary clues into niche-mediated renewal mechanisms. Leveraging endogenous bioelectric cues and crosstalk between gut, brain, and vascular niches further illuminates promising therapeutic opportunities. Emerging techniques like single-cell transcriptomics, organoids, microfluidics, artificial intelligence, in silico modeling, and transdifferentiation will continue to unravel niche complexity. By providing a comprehensive synthesis integrating diverse views on niche components, developmental transitions, and dynamics, this review unveils new layers of complexity integral to niche behavior and function, which unveil novel prospects to modulate niche function and provide revolutionary treatments for neurodegenerative diseases.

Probable Neuropsychological and Cognitive Complications Due to Cytokine Storm in Patients With COVID-19

Introduction

COVID-19 (coronavirus disease 2019) was first identified in China in December 2019 and is rapidly spreading worldwide as a pandemic. Since COVID-19 causes mild to severe acute respiratory syndrome, most studies in this context have focused on pathogenesis primarily in the respiratory system. However, evidence shows that the central nervous system (CNS) may also be affected by COVID-19. Since COVID-19 is spreading, it is necessary to study its possible cognitive effects on COVID-19 patients and their recovery.

Methods

The articles used in this study were searched by keywords, such as cytokine storm and COVID-19, COVID-19 and executive dysfunction, cognitive disorder, and COVID-19, central nervous system (CNS) and COVID-19, coronavirus, neuroinvasion in Science Direct, Scopus, PubMed, Embase, and Web of Science databases based on preferred reporting items for systematic reviews and meta-analysis (PRISMA) checklist. The study evaluates all observational studies published between December 2019 and April 2021 in peer-reviewed journals, including cross-sectional, cohort, case-control studies, case reports, and case series. The search result was 106 articles, of which 73 articles related to COVID-19, the stages of infection by this virus, its effect on the nervous system and neurological symptoms, the cytokine storm caused by this infection, and the possible cognitive consequences caused by this virus in patients, has been reviewed. Other articles were not checked due to their limited relevance to the topic under discussion.

Results

Studies showed that neurons may be directly affected by severe acute respiratory syndrome coronavirus (SARS-CoV)-1 and SARS-CoV-2. Furthermore, various studies indicated that systemic inflammation (so-called "cytokine storm") is also responsible for brain damage induced by infection with SARS-CoV-1 and SARS-CoV-2. In such a way that these patients showed elevated levels of interleukin (IL-), 6, 8, and 10 and of tumor necrosis factor-alpha (TNF-α) in their blood.

Conclusion

Various cognitive defects have been observed following an increased level of cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6, 8. Therefore, due to the increased level of these pro-inflammatory factors in the brains of these patients, cognitive deficits can be expected, which need further investigation.

LRRK2 Kinase Inhibition Attenuates Neuroinflammation and Cytotoxicity in Animal Models of Alzheimer's and Parkinson's Disease-Related Neuroinflammation

Chronic neuroinflammation plays a crucial role in the progression of several neurodegenerative diseases (NDDs), including Parkinson's disease (PD) and Alzheimer's disease (AD). Intriguingly, in the last decade, leucine-rich repeat kinase-2 (LRRK2), a gene mutated in familial and sporadic PD, was revealed as a key mediator of neuroinflammation. Therefore, the anti-inflammatory properties of LRRK2 inhibitors have started to be considered as a disease-modifying treatment for PD; however, to date, there is little evidence on the beneficial effects of targeting LRRK2-related neuroinflammation in preclinical models. In this study, we further validated LRRK2 kinase modulation as a pharmacological intervention in preclinical models of AD- and PD-related neuroinflammation. Specifically, we reported that LRRK2 kinase inhibition with MLi2 and PF-06447475 (PF) molecules attenuated neuroinflammation, gliosis and cytotoxicity in mice with intracerebral injection of Aβ1-42 fibrils or α-syn preformed fibrils (pffs). Moreover, for the first time in vivo, we showed that LRRK2 kinase activity participates in AD-related neuroinflammation and therefore might contribute to AD pathogenesis. Overall, our findings added evidence on the anti-inflammatory effects of LRRK2 kinase inhibition in preclinical models and indicate that targeting LRRK2 activity could be a disease-modifying treatment for NDDs with an inflammatory component.

Scrophularia buergeriana Extract (Brainon) Attenuates Neuroinflammation in BV-2 Microglia Cells and Promotes Neuroprotection in SH-SY5Y Neuroblastoma Cells

Microglia-induced neuroinflammation is one of the causative factors in cognitive dysfunction and neurodegenerative disorders. Our previous studies have revealed several benefits of Scrophularia buergeriana extract (Brainon^®) in the central nervous system, but the underlying mechanism of action has not been elucidated. This study is purposed to investigate the anti-inflammatory and neuroprotective mechanisms of Brainon in the BV-2 condition SH-SY5Y model. Lipopolysaccharide (LPS)-induced BV-2 conditioned media (CM) were used to treat SH-SY5Y cells to investigate neuroprotective effects of the extract against microglial cytotoxicity. Results demonstrated that pretreated Brainon decreased nitric oxide release, the inducible nitric oxide synthase expression level, and expression of cytokines like interleukin-6, interleukin-1β, and tumor necrosis factor-α by blocking expression of TLR4/MyD88 and NLRP3 and suppressing nuclear factor κB/AP-1 and p38/JNK signaling pathways in LPS-induced BV-2 cells. In addition, when SH-SY5Y cells were treated with CM, pretreatment with Brainon increased neuronal viability by upregulating expression of antioxidant proteins like as SODs and Gpx-1. Increased autophagy and mitophagy-associated proteins also provide important clues for SH-SY5Y to prevent apoptosis by Brainon. Brainon also modulated mTOR/AMPK signaling to clear misfolded proteins or damaged mitochondria via auto/mitophagy to protect SH-SY5Y cells from CM. Taken together, these results indicate that Brainon could reduce inflammatory mediators secreted from BV-2 cells and prevent apoptosis by increasing antioxidant and auto/mitophagy mechanisms by regulating mTOR/AMPK signaling in SH-SY5Y cells. Therefore, Brainon has the potential to be developed as a natural product in a brain health functional food to inhibit cognitive decline and neuronal death.

The case for complement component 5 as a target in neurodegenerative disease

INTRODUCTION

Complement-based drug discovery is undergoing a renaissance, empowered by new advances in structural biology, complement biology and drug development. Certain components of the complement pathway, particularly C1q and C3, have been extensively studied in the context of neurodegenerative disease, and established as key therapeutic targets. C5 also has huge therapeutic potential in this arena, with its druggability clearly demonstrated by the success of C5-inhibitor eculizumab.

AREAS COVERED

We will discuss the evidence supporting C5 as a target in neurodegenerative disease, along with the current progress in developing different classes of C5 inhibitors and the gaps in knowledge that will help progress in the field.

EXPERT OPINION

Validation of C5 as a therapeutic target for neurodegenerative disease would represent a major step forward for complement therapeutics research and has the potential to furnish disease-modifying drugs for millions of patients suffering worldwide. Key hurdles that need to be overcome for this to be achieved are understanding how C5a and C5b should be targeted to bring therapeutic benefit and demonstrating the ability to target C5 without creating vulnerability to infection in patients. This requires greater biological elucidation of its precise role in disease pathogenesis, supported by better chemical/biological tools.

Adult hippocampal neurogenesis in Alzheimer's disease: A roadmap to clinical relevance

Adult hippocampal neurogenesis (AHN) drops sharply during early stages of Alzheimer's disease (AD), via unknown mechanisms, and correlates with cognitive status in AD patients. Understanding AHN regulation in AD could provide a framework for innovative pharmacological interventions. We here combine molecular, behavioral, and clinical data and critically discuss the multicellular complexity of the AHN niche in relation to AD pathophysiology. We further present a roadmap toward a better understanding of the role of AHN in AD by probing the promises and caveats of the latest technological advancements in the field and addressing the conceptual and methodological challenges ahead.

Association between dietary inflammatory index and cognitive impairment: A meta-analysis

Aims

Cognitive impairment is an increasingly urgent global public health challenge. Dietary Inflammatory Index (DII) is a literature-derived score that links diet to inflammation. The relationship between DII and cognitive impairment remains controversial. Therefore, our study aimed to analysis the role of DII on the risk of cognitive impairment by meta-analysis.

Methods

PubMed, Cochrane Library, MEDLINE, Web of Science and EMBASE databases were searched up to July 2022. Newcastle-Ottawa scale (NOS) and Joanna Briggs Institute (JBI) Checklist were performed to estimate the quality of studies.

Results

Nine observational studies with 19,379 subjects were included. Our study found that higher DII could elevate the risk of cognitive impairment (OR = 1.46, 95%CI = 1.26, 1.69). Meanwhile, the OR of cognitive impairment was 1.49 (95%CI = 1.21, 1.83) for cross-sectional studies and 1.42 (95%CI = 1.12, 1.79) for cohort studies, respectively.

Conclusion

Our meta-analysis indicated that higher DII (indicating a more pro-inflammatory diet) is related to increased risk of cognitive impairment.

Alzheimer's Disease: Challenges and a Therapeutic Opportunity to Treat It with a Neurotrophic Compound

Alzheimer’s disease (AD) is a progressive neurodegenerative disease with an insidious onset and multifactorial nature. A deficit in neurogenesis and synaptic plasticity are considered the early pathological features associated with neurofibrillary tau and amyloid β pathologies and neuroinflammation. The imbalance of neurotrophic factors with an increase in FGF-2 level and a decrease in brain derived neurotrophic factor (BDNF) and neurotrophin 4 (NT-4) in the hippocampus, frontal cortex and parietal cortex and disruption of the brain micro-environment are other characteristics of AD. Neurotrophic factors are crucial in neuronal differentiation, maturation, and survival. Several attempts to use neurotrophic factors to treat AD were made, but these trials were halted due to their blood-brain barrier (BBB) impermeability, short-half-life, and severe side effects. In the present review we mainly focus on the major etiopathology features of AD and the use of a small neurotrophic and neurogenic peptide mimetic compound; P021 that was discovered in our laboratory and was found to overcome the difficulties faced in the administration of the whole neurotrophic factor proteins. We describe pre-clinical studies on P021 and its potential as a therapeutic drug for AD and related neurodegenerative disorders. Our study is limited because it focuses only on P021 and the relevant literature; a more thorough investigation is required to review studies on various therapeutic approaches and potential drugs that are emerging in the AD field.

Stem Cells and the Microenvironment: Reciprocity with Asymmetry in Regenerative Medicine

Much of the current research in regenerative medicine concentrates on stem-cell therapy that exploits the regenerative capacities of stem cells when injected into different types of human tissues. Although new therapeutic paths have been opened up by induced pluripotent cells and human mesenchymal cells, the rate of success is still low and mainly due to the difficulties of managing cell proliferation and differentiation, giving rise to non-controlled stem cell differentiation that ultimately leads to cancer. Despite being still far from becoming a reality, these studies highlight the role of physical and biological constraints (e.g., cues and morphogenetic fields) placed by tissue microenvironment on stem cell fate. This asks for a clarification of the coupling of stem cells and microenvironmental factors in regenerative medicine. We argue that extracellular matrix and stem cells have a causal reciprocal and asymmetric relationship in that the 3D organization and composition of the extracellular matrix establish a spatial, temporal, and mechanical control over the fate of stem cells, which enable them to interact and control (as well as be controlled by) the cellular components and soluble factors of microenvironment. Such an account clarifies the notions of stemness and stem cell regeneration consistently with that of microenvironment.

Cross-translational models of late-onset cognitive sequelae and their treatment in pediatric brain tumor survivors

Pediatric brain tumor treatments have a high success rate, but survivors are at risk of cognitive sequelae that impact long-term quality of life. We summarize recent clinical and animal model research addressing pathogenesis or evaluating candidate interventions for treatment-induced cognitive sequelae. Assayed interventions encompass a broad range of approaches, including modifications to radiotherapy, modulation of immune response, prevention of treatment-induced cell loss or promotion of cell renewal, manipulation of neuronal signaling, and lifestyle/environmental adjustments. We further emphasize the potential of neuroimaging as a key component of cross-translation to contextualize laboratory research within broader clinical findings. This cross-translational approach has the potential to accelerate discovery to improve pediatric cancer survivors' long-term quality of life.

Roles of the Cannabinoid System in the Basal Ganglia in Parkinson’s Disease

Parkinson’s disease (PD) is a neurodegenerative disease usually caused by neuroinflammation, oxidative stress and other etiologies. Recent studies have found that the cannabinoid system present in the basal ganglia has a strong influence on the progression of PD. Altering the cannabinoid receptor activation status by modulating endogenous cannabinoid (eCB) levels can exert an anti-movement disorder effect. Therefore, the development of drugs that modulate the endocannabinoid system may be a novel strategy for the treatment of PD. However, eCB regulation is complex, with diverse cannabinoid receptor functions and the presence of dopaminergic, glutamatergic, and γ-aminobutyric signals interacting with cannabinoid signaling in the basal ganglia region. Therefore, the study of eCB is challenging. Here, we have described the function of the cannabinoid system in the basal ganglia and its association with PD in three parts (eCBs, cannabinoid receptors, and factors regulating the cannabinoid metabolism) and summarized the mechanisms of action related to the cannabinoid analogs currently aimed at treating PD. The shortcomings identified from previous studies and the directions that should be explored in the future will provide insights into new approaches and ideas for the future development of cannabinoid-based drugs and the treatment of PD.

Hypobaric Hypoxia Induces Deficits in Adult Neurogenesis and Social Interaction via Cyclooxygenase-1/ EP1 Receptor Pathway Activating NLRP3 Inflammasome

Low oxygen environments, like hypobaric hypoxia (HH), are common nodes in a number of diseases characterized by neuroinflammation, which is detrimental to the structural and functional aspects of hippocampal circuitry. Hypoxic conditions lead to elevation of inflammasome-mediated inflammation that may contribute to cognitive deficits. However, a systematic investigation of the impact of inflammasome-mediated neuroinflammation on the components of neurogenic niche during HH remains to be elusive. Cerebral hypoxia was induced in adult male Sprague Dawley rats via decreasing partial pressure of oxygen. The effect of HH (1, 3, and 7 days at 25,000 ft) on social memory, anxiety, adult neurogenesis, and NLRP3- (NLR family pyrin domain containing 3) mediated neuroinflammation in the dentate gyrus (DG) was explored in detail. Furthermore, we explored the therapeutic efficacy of cyclooxygenase-1 inhibitor (valeryl salicylate, 5 mg/kg/day, i.p.) and EP1 receptor (EP1R) antagonist (SC19220, 1 mg/kg/day, i.p.) on HH-induced deficits. Seven days of HH exposure induced alteration in social and anxiety-like behavior along with perturbation in adult neurogenesis. Elevation in NLRP3, caspase-1, and IL-1β levels was observed during HH from day 1. A notable increase in the COX-1/EP1R pathway in activated glial cells in DG was evident during HH. COX-1 inhibitor and EP1R antagonist mitigated the detrimental effects of HH on social memory, adult neurogenesis via blunting NLRP3-mediated inflammation. Our data showed induction of the COX-1/EP1R pathway in the glial cells, which is detrimental to neurogenesis and social memory, opening up the possibility that the COX-1/EP1R pathway is a plausible target for inflammasome-related neurogenesis impairments.

Transcutaneous electrical acupoint stimulation for postoperative cognitive dysfunction in geriatric patients with gastrointestinal tumor: a randomized controlled trial

Background

This study aimed to evaluate the effect of perioperative transcutaneous electrical acupoint stimulation (TEAS) on postoperative cognitive dysfunction (POCD) in older patients who were diagnosed with gastrointestinal tumor and received radical resection of gastrointestinal tumors under general anesthesia.

Methods

A total of 68 patients who received radical resection of gastrointestinal tumors under general anesthesia were randomly divided into two groups. TEAS group patients received TEAS treatment. The treatment time was 30 min before the induction of anesthesia until the end of the surgery, 1 day before operation and from the first day to the third day after the operation. Except on the day of surgery, we treated the patients for 30 min once a day. In the sham TEAS group, the electronic stimulation was not applied and the treatment was the same as the TEAS group. The primary outcome was perioperative cognition evaluated by the Mini-Mental State Examination (MMSE) and secondary outcomes were the perioperative level of interleukin-6 (IL-6), S100 calcium-binding protein β (S100β), and C-reactive protein (CRP).

Results

The postoperative score of MMSE, orientation, memory, and short-term recall in the sham TEAS group was significantly lower than the preoperative and TEAS group (P < 0.05). The incidence of POCD in the TEAS group (21.88%) was lower than those in the sham TEAS group (40.63%). S100β, IL-6, and CRP in the TEAS group were significantly lower than those in the sham TEAS group on the third day after the operation (P< 0.05). Postoperative S100β, IL-6, and CRP in two groups were significantly higher than those before operation except for S100β on the third day after the operation in the TEAS group (P < 0.05).

Conclusions

Perioperative TEAS treatment reduced the postoperative inflammatory response and increased the postoperative cognitive function score and decrease the incidence of POCD in geriatric patients with gastrointestinal tumor.

Trial registration

ClinicalTrials.gov NCT04606888. Registered on 27 October 2020. https://register.clinicaltrials.gov.

Reprogramming Glial Cells into Functional Neurons for Neuro-regeneration: Challenges and Promise

The capacity for neurogenesis in the adult mammalian brain is extremely limited and highly restricted to a few regions, which greatly hampers neuronal regeneration and functional restoration after neuronal loss caused by injury or disease. Meanwhile, transplantation of exogenous neuronal stem cells into the brain encounters several serious issues including immune rejection and the risk of tumorigenesis. Recent discoveries of direct reprogramming of endogenous glial cells into functional neurons have provided new opportunities for adult neuro-regeneration. Here, we extensively review the experimental findings of the direct conversion of glial cells to neurons in vitro and in vivo and discuss the remaining issues and challenges related to the glial subtypes and the specificity and efficiency of direct cell-reprograming, as well as the influence of the microenvironment. Although in situ glial cell reprogramming offers great potential for neuronal repair in the injured or diseased brain, it still needs a large amount of research to pave the way to therapeutic application.

Gene Expression Profile in Different Age Groups and Its Association with Cognitive Function in Healthy Malay Adults in Malaysia

The mechanism of cognitive aging at the molecular level is complex and not well understood. Growing evidence suggests that cognitive differences might also be caused by ethnicity. Thus, this study aims to determine the gene expression changes associated with age-related cognitive decline among Malay adults in Malaysia. A cross-sectional study was conducted on 160 healthy Malay subjects, aged between 28 and 79, and recruited around Selangor and Klang Valley, Malaysia. Gene expression analysis was performed using a HumanHT-12v4.0 Expression BeadChip microarray kit. The top 20 differentially expressed genes at p < 0.05 and fold change (FC) = 1.2 showed that PAFAH1B3, HIST1H1E, KCNA3, TM7SF2, RGS1, and TGFBRAP1 were regulated with increased age. The gene set analysis suggests that the Malay adult's susceptibility to developing age-related cognitive decline might be due to the changes in gene expression patterns associated with inflammation, signal transduction, and metabolic pathway in the genetic network. It may, perhaps, have important implications for finding a biomarker for cognitive decline and offer molecular targets to achieve successful aging, mainly in the Malay population in Malaysia.

New insights into glial scar formation after spinal cord injury

Severe spinal cord injury causes permanent loss of function and sensation throughout the body. The trauma causes a multifaceted torrent of pathophysiological processes which ultimately act to form a complex structure, permanently remodeling the cellular architecture and extracellular matrix. This structure is traditionally termed the glial/fibrotic scar. Similar cellular formations occur following stroke, infection, and neurodegenerative diseases of the central nervous system (CNS) signifying their fundamental importance to preservation of function. It is increasingly recognized that the scar performs multiple roles affecting recovery following traumatic injury. Innovative research into the properties of this structure is imperative to the development of treatment strategies to recover motor function and sensation following CNS trauma. In this review, we summarize how the regeneration potential of the CNS alters across phyla and age through formation of scar-like structures. We describe how new insights from next-generation sequencing technologies have yielded a more complex portrait of the molecular mechanisms governing the astrocyte, microglial, and neuronal responses to injury and development, especially of the glial component of the scar. Finally, we discuss possible combinatorial therapeutic approaches centering on scar modulation to restore function after severe CNS injury.

Adult Hippocampal Neurogenesis in Aging and Alzheimer's Disease

Cognitive deficits associated with Alzheimer's disease (AD) severely impact daily life for the millions of affected individuals. Progressive memory impairment in AD patients is associated with degeneration of the hippocampus. The dentate gyrus of the hippocampus, a region critical for learning and memory functions, is a site of adult neurogenesis in mammals. Recent evidence in humans indicates that hippocampal neurogenesis likely persists throughout life, but declines with age and is strikingly impaired in AD. Our understanding of how neurogenesis supports learning and memory in healthy adults is only beginning to emerge. The extent to which decreased neurogenesis contributes to cognitive decline in aging and AD remains poorly understood. However, studies in rodent models of AD and other neurodegenerative diseases raise the possibility that targeting neurogenesis may ameliorate cognitive dysfunction in AD. Here, we review recent progress in understanding how adult neurogenesis is impacted in the context of aging and AD.

The effect of dietary approaches to stop hypertension (DASH) diet on attention-deficit hyperactivity disorder (ADHD) symptoms: a randomized controlled clinical trial

BACKGROUND

The dietary approaches to stop hypertension (DASH) diet have several components like high amounts of fruits, vegetables, low-fat dairy products, and vitamin C and low amounts of simple sugars that might improve attention-deficit hyperactivity disorder (ADHD) symptoms. We aimed to investigate the effect of a DASH diet on children (aged 6-12 years) with ADHD, for the first time.

METHODS

Participants were randomized to receive a DASH or a control diet for 12 weeks. The severity of ADHD symptoms [determined by abbreviated 10-item Conner's scale (ACS), 18-item Swanson, Nolan and Pelham (SNAP-IV) scale and strengths and difficulties questionnaire (SDQ)] were assessed every four weeks.

RESULTS

Eighty children completed the study. After adjustment for confounders, parent (- 4.71 for the DASH group vs. - 3 for the control group) and teacher-reported (- 5.35 vs. - 1.87) ACS scores, parent-, teacher-, child-reported hyperactivity (- 1.40 vs. - 0.66, - 1.95 vs. -0.63, - 1.60 vs. - 0.43, respectively), emotional symptoms (- 1.50 vs. - 0.45, - 1.42 vs. - 0.63, and - 1.09 vs. - 0.61, respectively), and total SDQ scores (- 3.81 vs. - 1.65, - 4.11 vs. - 1.23, - 4.44 vs. - 1.26, respectively), teacher-reported of conduct problems (- 1.42 vs. - 0.63), peer relationship problems (- 0.87 vs. - 0.07), and prosocial behaviors (1.36 vs. 0.08) assessed by the SDQ were significantly improved in the DASH group compared with the control group (P < 0.05).

CONCLUSION

Adherence to a DASH-style diet might improve ADHD symptoms. Further RCTs which include participants from both sexes and with longer follow-up periods are needed to warrant current findings (The trial registration code: IRCT20130223012571N6; http://irct.ir/trial/12623 ). Trial registration Trial registration number: The trial was registered in the Iranian registry of clinical trials (registration code: IRCT20130223012571N6), URL: http://irct.ir/trial/12623 .

Preclinical Evaluation of TSPO and MAO-B PET Radiotracers in an LPS Model of Neuroinflammation

Discovery of novel PET radiotracers targeting neuroinflammation (microglia and astrocytes) is actively pursued. Employing a lipopolysaccharide (LPS) rat model, this longitudinal study evaluated the translocator protein 18-kDa radiotracer [¹⁸F]FEPPA (primarily microglia) and monoamine oxidase B radiotracers [¹¹C]L-deprenyl and [¹¹C]SL25.1188 (astrocytes preferred). Increased [¹⁸F]FEPPA binding peaked at 1 week in LPS-injected striatum whereas increased lazabemide-sensitive [¹¹C]L-deprenyl binding developed later. No increase in radiotracer uptake was observed for [¹¹C]SL25.1188. The unilateral intrastriatal LPS rat model may serve as a useful tool for benchmarking PET tracers targeted toward distinct phases of neuroinflammatory reactions involving both microglia and astrocytes.

Endoplasmic reticulum stress-related neuroinflammation and neural stem cells decrease in mice exposure to paraquat

Paraquat (PQ), a widely used herbicide, could cause neurodegenerative diseases, yet the mechanism remains incompletely understood. This study aimed to investigate the direct effect of PQ on NSC in vivo and its possible mechanism. Adult C57BL/6 mice were subcutaneously injected with 2 mg/kg PQ, 20 mg/kg PQ or vehicle control once a week for 2 weeks, and sacrificed 1 week after the last PQ injection. Furthermore, extra experiments with Tauroursodeoxycholic Acid (TUDCA) intervention were performed to observe the relationship between ER stress, neuroinflammation and the neural stem cell (NSC) impairment. The results showed that 20 mg/kg PQ caused the NSC number decrease in both subgranular zones (SGZ) and subventricular zone (SVZ). Further analysis indicated that the 20 mg/kg PQ suppressed the proliferation of NSC, without affecting the apoptosis. Moreover, 20 mg/kg PQ also induced ER stress in microglia and caused neuroinflammation in SGZ and SVZ. Interestingly, the ER stress inhibitor could simultaneously ameliorate the neuroinflammation and NSC reduction. These data suggested that increased ER stress in microglia might be a possible pathway for PQ-induced neuroinflammation and NSC impairment. That is a previously unknown mechanism for PQ neurotoxicity.

Childhood Hypertension and Effects on Cognitive Functions: Mechanisms and Future Perspectives

Pediatric hypertension is currently one of the most common health concerns in children, given its effects not only on cardiovascular but also cognitive functions. There is accumulating evidence suggesting neurocognitive dysfunction in hypertensive children that could persist even into adulthood. Identifying the precise mechanism(s) underlying the association between childhood hypertension and cognitive dysfunction is crucial as it could potentially lead to the discovery of "druggable" biological targets facilitating the development of treatments. Here, we discuss some of the proposed pathophysiological mechanisms underlying childhood hypertension and cognitive deficits and suggest strategies to address some of the current challenges in the field. The various research studies involving hypertensive adults indicate that long-term hypertension may produce abnormal cerebrovascular reactivity, chronic inflammation, autonomic dysfunction, or hyperinsulinemia and hypercholesterolemia, which could lead to alterations in the brain's structure and functions, resulting in cognitive dysfunction. In light of the current literature, we propose that dysregulation of the hypothalamus-pituitaryadrenal axis, modifications in endothelial brain-derived neurotrophic factor and the gut microbiome may also modulate cognitive functions in hypertensive individuals. Moreover, the above-mentioned pathological states may further intensify the detrimental effects of hypertension on cognitive functions. Thus, treatments that target not only hypertension but also its downstream effects may prove useful in ameliorating hypertension-induced cognitive deficits. Much remains to be clarified about the mechanisms and treatments of hypertension-induced cognitive outcomes in pediatric populations. Addressing the knowledge gaps in this field entails conducting not only clinical research but also rigorous basic and translational studies.

Neurodegenerative Diseases and Cell Reprogramming

Neurodegenerative diseases have different types according to the onset of the disease, the time course, and the underlying pathology. Although the dogma that brain cells cannot regenerate has changed, the normal regenerative process of the brain is usually not sufficient to restore brain tissue defects after different pathological insults. Stem cell therapy and more recently cell reprogramming could achieve success in the process of brain renewal. This review article presents recent advances of stem cell therapies in neurodegenerative diseases and the role of cell reprogramming in the scope of optimizing a confined condition that could direct signaling pathways of the cell toward a specific neural lineage. Further, we will discuss different types of transcriptional factors and their role in neural cell fate direction.

Multimodal treatment for spinal cord injury: a sword of neuroregeneration upon neuromodulation

Spinal cord injury is linked to the interruption of neural pathways, which results in irreversible neural dysfunction. Neural repair and neuroregeneration are critical goals and issues for rehabilitation in spinal cord injury, which require neural stem cell repair and multimodal neuromodulation techniques involving personalized rehabilitation strategies. Besides the involvement of endogenous stem cells in neurogenesis and neural repair, exogenous neural stem cell transplantation is an emerging effective method for repairing and replacing damaged tissues in central nervous system diseases. However, to ensure that endogenous or exogenous neural stem cells truly participate in neural repair following spinal cord injury, appropriate interventional measures (e.g., neuromodulation) should be adopted. Neuromodulation techniques, such as noninvasive magnetic stimulation and electrical stimulation, have been safely applied in many neuropsychiatric diseases. There is increasing evidence to suggest that neuromagnetic/electrical modulation promotes neuroregeneration and neural repair by affecting signaling in the nervous system; namely, by exciting, inhibiting, or regulating neuronal and neural network activities to improve motor function and motor learning following spinal cord injury. Several studies have indicated that fine motor skill rehabilitation training makes use of residual nerve fibers for collateral growth, encourages the formation of new synaptic connections to promote neural plasticity, and improves motor function recovery in patients with spinal cord injury. With the development of biomaterial technology and biomechanical engineering, several emerging treatments have been developed, such as robots, brain-computer interfaces, and nanomaterials. These treatments have the potential to help millions of patients suffering from motor dysfunction caused by spinal cord injury. However, large-scale clinical trials need to be conducted to validate their efficacy. This review evaluated the efficacy of neural stem cells and magnetic or electrical stimulation combined with rehabilitation training and intelligent therapies for spinal cord injury according to existing evidence, to build up a multimodal treatment strategy of spinal cord injury to enhance nerve repair and regeneration.

Fast-tracking regenerative medicine for traumatic brain injury

Traumatic brain injury remains a global health crisis that spans all demographics, yet there exist limited treatment options that may effectively curtail its lingering symptoms. Traumatic brain injury pathology entails a progression from primary injury to inflammation-mediated secondary cell death. Sequestering this inflammation as a means of ameliorating the greater symptomology of traumatic brain injury has emerged as an attractive treatment prospect. In this review, we recapitulate and evaluate the important developments relating to regulating traumatic brain injury-induced neuroinflammation, edema, and blood-brain barrier disintegration through pharmacotherapy and stem cell transplants. Although these studies of stand-alone treatments have yielded some positive results, more therapeutic outcomes have been documented from the promising area of combined drug and stem cell therapy. Harnessing the facilitatory properties of certain pharmaceuticals with the anti-inflammatory and regenerative effects of stem cell transplants creates a synergistic effect greater than the sum of its parts. The burgeoning evidence in favor of combined drug and stem cell therapies warrants more elaborate preclinical studies on this topic in order to pave the way for later clinical trials.

Acute Nicotine Treatment Alleviates LPS-Induced Impairment of Fear Memory Reconsolidation Through AMPK Activation and CRTC1 Upregulation in Hippocampus

BACKGROUND

Fear memory is a fundamental capability for animals and humans to survive. Its impairment results in the disability to avoid danger. When memory is reactivated, a reconsolidation process, which can be disrupted by various stimuli, including inflammation, is required to become permanent. Nicotine has been shown to improve cognitive deficits induced by inflammation and other stimuli. Therefore, in the present study, we investigated the effect of nicotine on lipopolysaccharide (LPS)-induced impairment of fear memory reconsolidation and the underlying mechanism.

METHODS

Step-through inhibitory avoidance task was recruited to study fear memory of rat, i.p. LPS (0.5 mg/kg) treatment was used to induce inflammation, and western blot and immunostaining were applied to detect protein expression and distribution in medial prefrontal cortex and hippocampus.

RESULTS

Our data showed that LPS induced fear memory reconsolidation impairment without affecting retrieval. In addition, LPS significantly increased inflammation factors tumor necrosis factor-α and interleukin-1 beta and decreased CREB-regulated transcription coactivator 1 (CRTC1) expression and adenosine monophosphate-activated protein kinase (AMPK) activation in hippocampus. More importantly, LPS significantly decreased CRTC1 expression and AMPK activation in neurons by activating microglia cells. Of note, either nicotine treatment or activation of AMPK by intracerebroventricular infusion of metformin reduced LPS-induced impairment of fear memory reconsolidation and ameliorated inflammation factor tumor necrosis factor-α and interleukin-1 beta as well as the expression of CRTC1.

CONCLUSIONS

In conclusion, our results showed that acute nicotine treatment alleviates LPS-induced impairment of fear memory reconsolidation through activation of AMPK and upregulation of CRTC1 in hippocampus.

Effects of Exercise on Cognitive Performance in Older Adults: A Narrative Review of the Evidence, Possible Biological Mechanisms, and Recommendations for Exercise Prescription

Physical activity and exercise have emerged as potential methods to improve brain health among older adults. However, there are currently no physical activity guidelines aimed at improving cognitive function, and the mechanisms underlying these cognitive benefits are poorly understood. The purpose of this narrative review is to present the current evidence regarding the effects of physical activity and exercise on cognition in older adults without cognitive impairment, identify potential mechanisms underlying these effects, and make recommendations for exercise prescription to enhance cognitive performance. The review begins with a summary of evidence of the effect of chronic physical activity and exercise on cognition. Attention then turns to four main biological mechanisms that appear to underlie exercise-induced cognitive improvement, including the upregulation of growth factors and neuroplasticity, inhibition of inflammatory biomarker production, improved vascular function, and hypothalamic-pituitary-adrenal axis regulation. The last section provides an overview of exercise parameters known to optimize cognition in older adults, such as exercise type, frequency, intensity, session duration, and exercise program duration.

Seizure-induced neuroinflammation contributes to ectopic neurogenesis and aggressive behavior in pilocarpine-induced status epilepticus mice

Epilepsy is a chronic neurological disorder often associated with recurrent seizures. A growing body of evidence suggests that seizures cause structural and functional alterations of the brain. It is reported that behavioral abnormalities frequently occur in patients with epilepsy and experimental epilepsy models. However, the precise pathological mechanisms associated with these epilepsy comorbidities remain largely unknown. Neurogenesis persists throughout life in the hippocampal dentate gyrus (DG) to maintain proper brain function. However, aberrant neurogenesis usually generates abnormal neural circuits and consequently causes neuronal dysfunction. Neuroinflammatory responses are well known to affect neurogenesis and lead to aberrant reorganization of neural networks in the hippocampal DG. Here, in this study, we observed a significant increase in neuroinflammation and in the proliferation and survival of newborn granular cells in the hippocampus of pilocarpine-induced status epilepticus (SE) mice. More importantly, these proliferating and surviving newborn granular cells are largely ectopically located in the hippocampal DG hilus region. Our behavior test demonstrated that SE mice displayed severe aggressive behavior. Pharmacological inhibition of neuroinflammation, however, suppressed the ectopic neurogenesis and countered the enhanced aggressive behavior in SE mice, indicating that seizure-induced neuroinflammation may contribute to ectopic neurogenesis and aggressive behavior in SE mice. These findings establish a key role for neuroinflammation in seizure-induced aberrant neurogenesis and aggressive behavior. Suppressing neuroinflammation in the epileptic brain may reduce ectopic neurogenesis and effectively block the pathophysiological process that leads to aggressive behavior in TLE mice.

Neuroinflammation and Neurogenesis in Alzheimer's Disease and Potential Therapeutic Approaches

In adult brain, new neurons are generated throughout adulthood in the subventricular zone and the dentate gyrus; this process is commonly known as adult neurogenesis. The regulation or modulation of adult neurogenesis includes various intrinsic pathways (signal transduction pathway and epigenetic or genetic modulation pathways) or extrinsic pathways (metabolic growth factor modulation, vascular, and immune system pathways). Altered neurogenesis has been identified in Alzheimer's disease (AD), in both human AD brains and AD rodent models. The exact mechanism of the dysregulation of adult neurogenesis in AD has not been completely elucidated. However, neuroinflammation has been demonstrated to alter adult neurogenesis. The presence of various inflammatory components, such as immune cells, cytokines, or chemokines, plays a role in regulating the survival, proliferation, and maturation of neural stem cells. Neuroinflammation has also been considered as a hallmark neuropathological feature of AD. In this review, we summarize current, state-of-the art perspectives on adult neurogenesis, neuroinflammation, and the relationship between these two phenomena in AD. Furthermore, we discuss the potential therapeutic approaches, focusing on the anti-inflammatory and proneurogenic interventions that have been reported in this field.

Neurocognitive Decline Following Radiotherapy: Mechanisms and Therapeutic Implications

The brain undergoes ionizing radiation (IR) exposure in many clinical situations, particularly during radiotherapy for malignant brain tumors. Cranial radiation therapy is related with the hazard of long-term neurocognitive decline. The detrimental ionizing radiation effects on the brain closely correlate with age at treatment, and younger age associates with harsher deficiencies. Radiation has been shown to induce damage in several cell populations of the mouse brain. Indeed, brain exposure causes a dysfunction of the neurogenic niche due to alterations in the neuronal and supporting cell progenitor signaling environment, particularly in the hippocampus—a region of the brain critical to memory and cognition. Consequent deficiencies in rates of generation of new neurons, neural differentiation and apoptotic cell death, lead to neuronal deterioration and lasting repercussions on neurocognitive functions. Besides neural stem cells, mature neural cells and glial cells are recognized IR targets. We will review the current knowledge about radiation-induced damage in stem cells of the brain and discuss potential treatment interventions and therapy methods to prevent and mitigate radiation related cognitive decline.

Complement activation sustains neuroinflammation and deteriorates adult neurogenesis and spatial memory impairment in rat hippocampus following sleep deprivation

BACKGROUND

An association between neuroinflammation, reduced adult neurogenesis, and cognitive impairment has been established in sleep deprivation (SD). Complement receptors are expressed on neuronal and glial cells, thus, regulate the neuroinflammation, neurogenesis and learning/memory. However, understanding of the effect of SD on the brain-immune system interaction associated with cognitive dysfunction and its mechanisms is obscure. We hypothesized that complement activation induced changes in inflammatory and neurogenesis related proteins might be involved in the cognitive impairment during SD.

METHODOLOGY

Adult male Sprague Dawley rats were used. Rats were sleep deprived for 48 h using a novel automated SD apparatus. Dosage of BrdU (50 mg/kg/day, i.p. in 0.07 N NaOH), complement C3a receptor antagonist (C3aRA; SB290157; 1 mg/kg/day, i.p.) in 1.16% v/v PBS and complement C5a receptor antagonist (C5aRA; W-54011; 1 mg/kg/day, i.p.) in normal saline were used. Rats were subjected to spatial memory evaluation following SD. Hippocampal tissue was collected for biochemical, molecular, and immunohistochemical studies. T-test and ANOVA were used for the statistical analysis.

RESULTS

An up-regulation in the levels of complement components (C3, C5, C3a, C5a) and receptors (C3aR and C5aR) in hippocampus, displayed the complement activation during SD. Selective antagonism of C3aR/C5aR improved the spatial memory performance of sleep-deprived rats. C3aR antagonist (C3aRA) or C5aR antagonist (C5aRA) treatment inhibited the gliosis, maintained inflammatory cytokines balance in hippocampus during SD. Complement C3aR/C5aR antagonism improved hippocampal adult neurogenesis via up-regulating the BDNF level following SD. Administration of C3aRA and C5aRA significantly maintained synaptic homeostasis in hippocampus after SD. Gene expression analysis showed down-regulation in the mRNA levels of signal transduction pathways (Notch and Wnt), differentiation and axogenous proteins, which were found to be improved after C3aRA/C5aRA treatment. These findings were validated at protein and cellular level. Changes in the corticosterone level and ATP-adenosine-NO pathway were established as the key mechanisms underlying complement activation mediated consequences of SD.

CONCLUSION

Our study suggests complement (C3a-C3aR and C5a-C5aR) activation as the novel mechanism underlying spatial memory impairment via promoting neuroinflammation and adult neurogenesis decline in hippocampus during SD, thereby, complement (C3aR/C5aR) antagonist may serve as the novel therapeutics to improve the SD mediated consequences.

The relationship of CRP and cognition in cognitively normal older Mexican Americans: A cross-sectional study of the HABLE cohort

C-reactive protein (CRP) is a biomarker for cardiovascular events and also has been studied as a biomarker for cognitive decline. By the year 2050 the Hispanic population in the United States will reach 106 million, and 65% of those will be of Mexican heritage. The purpose of this study was to evaluate the association between CRP levels and cognitive functioning in a sample of Mexican American older adults. A cross-sectional analysis of data from 328 cognitive normal, Mexican American participants from the community-based Health and Aging Brain Among Latino Elders (HABLE) study were performed. Statistical methods included t-test, chi square, multiple linear regression, and logistic regression modeling. Cognitive performance was measured by the Mini Mental State Examination (MMSE), Logical Memory I and II, Digit Span, FAS, and Animal Naming tests. Age, years of education, gender, diagnostic of hypertension, diabetes, and dyslipidemia were entered in the model as covariates. High CRP levels significantly predicted FAS scores (B = -0.135, P = .01), even after adjusting for covariates. Education (B = 0.30, P < .05), and diagnosis of hypertension (B = -0.12, P = .02) were also independent predictors of FAS scores. Participants with higher CRP levels had greater adjusted odds of poorer performance in the FAS test (OR = 1.75, 95% CI = 1.13-2.72, P = .01) when compared to participants with lower CRP levels. This was also true for participants with hypertension (OR = 2.20, 95% CI = 1.34-3.60, P < .05). Higher CRP levels were not associated with MMSE, logical memory, digit span, and animal naming scores. In conclusion, our study showed a clear association between CRP levels and verbal fluency and executive function in a cognitively normal community-dwelling population of Mexican-Americans.

Peptide-modified, hyaluronic acid-based hydrogels as a 3D culture platform for neural stem/progenitor cell engineering

Neural stem/progenitor cell (NS/PC)-based therapies have shown exciting potential for regeneration of the central nervous system (CNS) and NS/PC cultures represent an important resource for disease modeling and drug screening. However, significant challenges limiting clinical translation remain, such as generating large numbers of cells required for model cultures or transplantation, maintaining physiologically representative phenotypes ex vivo and directing NS/PC differentiation into specific fates. Here, we report that culture of human NS/PCs in 3D, hyaluronic acid (HA)-rich biomaterial microenvironments increased differentiation toward oligodendrocytes and neurons over 2D cultures on laminin-coated glass. Moreover, NS/PCs in 3D culture exhibited a significant reduction in differentiation into reactive astrocytes. Many NS/PC-derived neurons in 3D, HA-based hydrogels expressed synaptophysin, indicating synapse formation, and displayed electrophysiological characteristics of immature neurons. While inclusion of integrin-binding, RGD peptides into hydrogels resulted in a modest increase in numbers of viable NS/PCs, no combination of laminin-derived, adhesive peptides affected differentiation outcomes. Notably, 3D cultures of differentiating NS/PCs were maintained for at least 70 days in medium with minimal growth factor supplementation. In sum, results demonstrate the use of 3D, HA-based biomaterials for long-term expansion and differentiation of NS/PCs toward oligodendroglial and neuronal fates, while inhibiting astroglial fates. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 704-718, 2019.

Traditional Chinese medicine-based neurorestorative therapy for Alzheimer’s and Parkinson’s disease

The prevalence of multiple neurodegenerative diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD), has been dramatically increasing, particularly in the aging population. However, the currently available therapies merely alleviate the symptoms of these diseases and are unable to retard disease progression significantly. Traditional Chinese medicine (TCM) has been used in clinical practice for thousands of years for ameliorating symptoms or interfering with the pathogenesis of aging- associated diseases. Modern pharmacological studies have proved that TCM imparts disease-modifying therapeutic effects against these diseases, such as protection of neurons, clearance of protein aggregates, and regulation of neuroinflammation. This review summarizes the evidence from recent studies on AD and PD therapies regarding the neuroprotective activities and molecular mechanisms of a series of TCM formulations comprising herbs and their active ingredients. The findings of this review support the use of TCM as an alternative source of therapy for the treatment of neurodegenerative diseases.

[Antioxidant and anti-inflammatory modulation of exercise during aging]

Aging is characterised by a gradual loss of the functional reserve. This, along with the fostering of sedentary habits and the increase in risk factors, causes a deterioration of antioxidant defences and an increase of the circulatory levels of inflammatory and oxidative markers, boosting a low-rate chronic inflammation, defined as inflamm-aging. This phenomenon is present in the aetiopathology of chronic diseases, as well as in cognitive deterioration cases associated with aging. The objective of this review is to describe the modulation of antioxidant and anti-inflammatory effects of physical exercise of moderate intensity and volume in the elderly. Evidence of its effectiveness as a non-pharmacological resource is presented, which decreases some deleterious effects of aging. This is mainly due to its neuroprotective action, the increase in circulating anti-inflammatory markers, and the improvement of antioxidant defence derived from its practice.

Proliferative hippocampal activity in a group of patients with Rasmussen's encephalitis: Neuronal, glial, and BDNF tissue expression correlations

Rasmussen's encephalitis (RE) is a rare and devastating unilateral inflammatory brain disease that causes severe and intractable partial epilepsy. It has been shown that epilepsy and subsequent inflammation have deleterious influence on hippocampal cell survival and neurogenesis, but this still has not been systematically explored in human tissue. In this study, we investigated the correlation between inflammation and epilepsy as well as the rates of hippocampal gliogenesis and neurogenesis in a pediatric group of six patients with RE and six control cases. The dentate gyrus (DG) samples were obtained from patients who underwent surgery for intractable RE. Sections were processed for immunohistochemistry using antibodies against sex determining region Y-box 2 (Sox2), nestin, human protein encoded by MKI67 gen (Ki67), and brain-derived neurotrophic factor (BDNF). There was an increase in the number of Ki67-positive granule cells in the DG of patients with RE in comparison with the autopsy control group, but no statistical difference for Sox2-positive cells was observed between these groups. Nestin immunolabeling was less intense in the RE group while BDNF expression was increased. Neurons that were BDNF-positive were found in DG from patients with RE but not in the control group. In patients with RE, few nestin-positive cells in DG were also positive for BDNF, unlike in controls which showed no colocalization for these two markers. These results suggest a proliferation activity in the DG subfield of patients with RE, and also future studies are necessary to address the role of new cells in the hippocampus of patients with RE.

Sex Steroids, Adult Neurogenesis, and Inflammation in CNS Homeostasis, Degeneration, and Repair

Sex steroidal hormones coordinate the development and maintenance of tissue architecture in many organs, including the central nervous systems (CNS). Within the CNS, sex steroids regulate the morphology, physiology, and behavior of a wide variety of neural cells including, but not limited to, neurons, glia, endothelial cells, and immune cells. Sex steroids spatially and temporally control distinct molecular networks, that, in turn modulate neural activity, synaptic plasticity, growth factor expression and function, nutrient exchange, cellular proliferation, and apoptosis. Over the last several decades, it has become increasingly evident that sex steroids, often in conjunction with neuroinflammation, have profound impact on the occurrence and severity of neuropsychiatric and neurodegenerative disorders. Here, I review the foundational discoveries that established the regulatory role of sex steroids in the CNS and highlight recent advances toward elucidating the complex interaction between sex steroids, neuroinflammation, and CNS regeneration through adult neurogenesis. The majority of recent work has focused on neuroinflammatory responses following acute physical damage, chronic degeneration, or pharmacological insult. Few studies directly assess the role of immune cells in regulating adult neurogenesis under healthy, homeostatic conditions. As such, I also introduce tractable, non-traditional models for examining the role of neuroimmune cells in natural neuronal turnover, seasonal plasticity of neural circuits, and extreme CNS regeneration.

Neuropathological Consequences of Gestational Exposure to Concentrated Ambient Fine and Ultrafine Particles in the Mouse

Increasing evidence indicates that the central nervous system (CNS) is a target of air pollution. We previously reported that postnatal exposure of mice to concentrated ambient ultrafine particles (UFP; ≤100 nm) via the University of Rochester HUCAPS system during a critical developmental window of CNS development, equivalent to human 3rd trimester, produced male-predominant neuropathological and behavioral characteristics common to multiple neurodevelopmental disorders, including autism spectrum disorder (ASD), in humans. The current study sought to determine whether vulnerability to fine (≤2.5 μm) and UFP air pollution exposure extends to embryonic periods of brain development in mice, equivalent to human 1st and 2nd trimesters. Pregnant mice were exposed 6 h/day from gestational days (GDs) 0.5-16.5 using the New York University VACES system to concentrated ambient fine/ultrafine particles at an average concentration of 92.69 μg/m3 over the course of the exposure period. At postnatal days (PNDs) 11-15, neuropathological consequences were characterized. Gestational air pollution exposures produced ventriculomegaly, increased corpus callosum (CC) area and reduced hippocampal area in both sexes. Both sexes demonstrated CC hypermyelination and increased microglial activation and reduced total CC microglia number. Analyses of iron deposition as a critical component of myelination revealed increased iron deposition in the CC of exposed female offspring, but not in males. These findings demonstrate that vulnerability of the brain to air pollution extends to gestation and produces features of several neurodevelopmental disorders in both sexes. Further, they highlight the importance of the commonalities of components of particulate matter exposures as a source of neurotoxicity and common CNS alterations.

Neuroinflammation and physical exercise as modulators of adult hippocampal neural precursor cell behavior

The dentate gyrus of the hippocampus is a plastic structure where adult neurogenesis constitutively occurs. Cell components of the neurogenic niche are source of paracrine as well as membrane-bound factors such as Notch, Bone Morphogenetic Proteins, Wnts, Sonic Hedgehog, cytokines, and growth factors that regulate adult hippocampal neurogenesis and cell fate decision. The integration and coordinated action of multiple extrinsic and intrinsic cues drive a continuous decision process: if adult neural stem cells remain quiescent or proliferate, if they take a neuronal or a glial lineage, and if new cells proliferate, undergo apoptotic death, or survive. The proper balance in the molecular milieu of this neurogenic niche leads to the production of neurons in a higher rate as that of astrocytes. But this rate changes in face of microenvironment modifications as those driven by physical exercise or with neuroinflammation. In this work, we first review the cellular and molecular components of the subgranular zone, focusing on the molecules, active signaling pathways and genetic programs that maintain quiescence, induce proliferation, or promote differentiation. We then summarize the evidence regarding the role of neuroinflammation and physical exercise in the modulation of adult hippocampal neurogenesis with emphasis on the activation of progression from adult neural stem cells to lineage-committed progenitors to their progeny mainly in murine models.

Revisiting nicotine’s role in the ageing brain and cognitive impairment

Brain ageing is a complex process which in its pathologic form is associated with learning and memory dysfunction or cognitive impairment. During ageing, changes in cholinergic innervations and reduced acetylcholinergic tonus may trigger a series of molecular pathways participating in oxidative stress, excitotoxicity, amyloid-β toxicity, apoptosis, neuroinflammation, and perturb neurotrophic factors in the brain. Nicotine is an exogenous agonist of nicotinic acetylcholine receptors (nAChRs) and acts as a pharmacological chaperone in the regulation of nAChR expression, potentially intervening in age-related changes in diverse molecular pathways leading to pathology. Although nicotine has therapeutic potential, paradoxical effects have been reported, possibly due to its inverted U-shape dose-response effects or pharmacokinetic factors. Additionally, nicotine administration should result in optimum therapeutic effects without imparting abuse potential or toxicity. Overall, this review aims to compile the previous and most recent data on nicotine and its effects on cognition-related mechanisms and age-related cognitive impairment.

Neuroinflammation in traumatic brain injury: A chronic response to an acute injury

Every year, approximately 1.4 million US citizens visit emergency rooms for traumatic brain injuries. Formerly known as an acute injury, chronic neurodegenerative symptoms such as compromised motor skills, decreased cognitive abilities, and emotional and behavioral changes have caused the scientific community to consider chronic aspects of the disorder. The injury causing impact prompts multiple cell death processes, starting with neuronal necrosis, and progressing to various secondary cell death mechanisms. Secondary cell death mechanisms, including excitotoxicity, oxidative stress, mitochondrial dysfunction, blood-brain barrier disruption, and inflammation accompany chronic traumatic brain injury (TBI) and often contribute to long-term disabilities. One hallmark of both acute and chronic TBI is neuroinflammation. In acute stages, neuroinflammation is beneficial and stimulates an anti-inflammatory response to the damage. Conversely, in chronic TBI, excessive inflammation stimulates the aforementioned secondary cell death. Converting inflammatory cells from pro-inflammatory to anti-inflammatory may expand the therapeutic window for treating TBI, as inflammation plays a role in all stages of the injury. By expanding current research on the role of inflammation in TBI, treatment options and clinical outcomes for afflicted individuals may improve. This paper is a review article. Referred literature in this paper has been listed in the references section. The data sets supporting the conclusions of this article are available online by searching various databases, including PubMed. Some original points in this article come from the laboratory practice in our research center and the authors' experiences.

Photoprotection against UV-induced damage by skin-derived precursors in hairless mice

BACKGROUND

Skin photodamage is associated with UV-induced overproduction of reactive oxygen species (ROS) and the inactivation of NF-E2-related factor 2 (Nrf2). Skin-derived precursor cells (SKPs), a population of dermal stem cells, are considered to be involved in wound repair and skin regeneration through the activation of Nrf2. However, no reports concentrate on the treatment of skin photodamage with SKPs.

OBJECTIVE

To investigate the photoprotective role of SKPs against UV-induced damage in mice.

METHODS

Fifty Balb/c hairless mice were divided into five groups (n=10), namely, normal (no intervention), model, prevention, treatment, and control groups. The latter four groups were dorsally exposed to UVA+UVB irradiation over a 2-week period. Mice in the prevention group received weekly SKP injections for 2weeks the day before irradiation. Mice in the treatment and Hanks groups received a two-time injection of SKPs and Hanks, respectively, after irradiation. One week after final intervention, skin appearance, pathological alterations, and oxidative indicators were evaluated by enzyme-linked immunosorbent assay, immunohistochemical analysis, and western blotting.

RESULTS

After irradiation, lesions were observed on the dorsal skin of mice, including erythema, edema, scales, and wrinkles; however, these were significantly ameliorated by subcutaneous SKP injection. Hyperkeratosis, acanthosis, and spongiosis in the epidermis, as well as dermal papillae edema and inflammatory cell infiltration, were observed in both model and control groups; however, these conditions resolved with either pretreatment or posttreatment with SKPs. In addition, SKPs increased Nrf2, heme oxygenase-1, glutathione peroxidase, superoxide dismutase, catalase, and gluthathione expression, while decreasing levels of ROS, MDA, and H₂O₂.

CONCLUSIONS

These findings suggest that SKPs have a photoprotective role against UV-induced damage in mice, which may be associated with their ability to scavenge photo-oxidative insults and activate Nrf2.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials.