Systemic Response to Infection Induces Long-Term Cognitive Decline: Neuroinflammation and Oxidative Stress as Therapeutical Targets

The weight of multiple hits: how TBI and infectious encephalitis co-modulate adverse outcomes

BACKGROUND

Chronic neurologic deficits from traumatic brain injury (TBI) and subsequent infectious encephalitis are poorly characterized.

METHODS

Using TriNetX database we queried patients 18 years or older with a confirmed diagnosis of encephalitis between 2016 and 2024. Patient cohorts included those with a diagnosis of TBI at least one month before encephalitis (N = 1,038), those with a diagnosis of a TBI anytime before encephalitis (N = 1,886), and those with encephalitis but no TBI, (N = 45,210; N = 45,215). A murine model of controlled cortical impact (CCI) injury and Venezuelan equine encephalitis virus (VEEV) infection was used to reflect the clinical model, followed by extracting hippocampal tissue for bulk RNA sequencing and analysis.

RESULTS

Patients with a TBI history at least one month before infectious encephalitis have an increased risk of mortality, epilepsy, and dementia or delirium. Bulk RNA sequencing of the hippocampus from mice subjected to CCI injury and VEEV infection demonstrated that key pathways, specifically those involved in granzyme mediated cell death, were enriched compared to VEEV infection alone.

CONCLUSION

Our findings reveal that infectious encephalitis in patients with TBI history portends worse neurologic outcomes, and the hippocampus may be vulnerable to granzyme mediated cell death under these conditions.

Posthospitalization COVID-19 cognitive deficits at 1 year are global and associated with elevated brain injury markers and gray matter volume reduction

The spectrum, pathophysiology and recovery trajectory of persistent post-COVID-19 cognitive deficits are unknown, limiting our ability to develop prevention and treatment strategies. We report the 1-year cognitive, serum biomarker and neuroimaging findings from a prospective, national study of cognition in 351 COVID-19 patients who required hospitalization, compared with 2,927 normative matched controls. Cognitive deficits were global, associated with elevated brain injury markers and reduced anterior cingulate cortex volume 1 year after COVID-19. Severity of the initial infective insult, postacute psychiatric symptoms and a history of encephalopathy were associated with the greatest deficits. There was strong concordance between subjective and objective cognitive deficits. Longitudinal follow-up in 106 patients demonstrated a trend toward recovery. Together, these findings support the hypothesis that brain injury in moderate to severe COVID-19 may be immune-mediated, and should guide the development of therapeutic strategies.

Fasudil attenuates lipopolysaccharide-induced cognitive impairment in C57BL/6 mice through anti-oxidative and anti-inflammatory effects: Possible role of aquaporin-4

Introduction

Processes that generate systemic inflammation are strongly associated with neurodegenerative diseases. This study aimed to explore the potential anti-oxidative and anti-inflammatory effects of fasudil and its role in modulating aquaporin-4 (AQP-4) to improve cognitive impairment in a systemic inflammation model induced by lipopolysaccharide (LPS).

Method

fourty C57BL/6 mice were assigned to four groups, including sham, LPS, sham+fasudil, and LPS+fasudil). Intraperitoneal LPS was given (500 μg/kg/day) at hours 0, 24, 48, and 72, and fasudil (30 mg/kg) administered intraperitoneal injections 2 hours after LPS injection. The open field, Y-maze, and Novel object tasks was used to assess learning and memory. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α) in the hippocampus also measured as markers of oxidative stress and inflammation. Furthermore, the expression of AQP-4 measured in the intact and experimental groups.

Results

The results showed that Fasudil significantly improved memory and anxiety behavior induced by LPS in the open field maze, spatial recognition memory in the Y-maze, and performance in the novel object recognition task. It also mitigates hippocampal MDA and SOD levels. Additionally, fasudil ameliorated LPS-induced hippocampal levels of TNFα and IL-10 and increased hippocampal levels of AQP-4 expression in mice.

Conclusion

Our results suggest that fasudil in the LPS model of systemic inflammation could improve cognition by suppressing oxidative stress and inflammation and increasing AQP-4 protein expression. These findings highlighted the potential of fasudil as a neuroprotective agent. However, further research is required to fully understand its neuroprotective properties in the treatment of neurodegenerative disorders.

The Influence of Physical Activity and Positive Affect on the Relationship between Pain Severity and Cognitive Performance in Women with Fibromyalgia

Fibromyalgia, characterized by chronic pain and cognitive impairments, significantly impacts patients' quality of life. Physical exercise has been shown to improve cognitive functions and reduce pain severity. Additionally, positive affect enhances cognitive flexibility and facilitates better adaptation to chronic pain, suggesting that combining physical activity and positive affect could mitigate cognitive deficits in fibromyalgia patients. Objectives: The objective of this work is to explore the relationship between pain severity and cognitive performance through time spent doing moderate physical activity while taking into account the role of positive affect in fibromyalgia. Methods: This prospective study was structured into two phases of evaluation. First, pain severity, positive affect, and time spent performing moderate physical activity were evaluated, and one week later cognitive performance (assessed through the Stroop test) was also evaluated. The final sample consisted of 231 women with fibromyalgia. Moderated mediation analyses were performed using PROCESS. Results: The moderated mediation model showed that the effect of moderate physical activity on the relationship between pain severity and cognitive performance was significant for low levels of positive affect but not for moderate or high levels. That is, the indirect effect of pain intensity on cognitive performance through time spent doing moderate physical activity only has an effect when patients with fibromyalgia present low levels of positive affect. However, there was no significant indirect effect in the simple mediation model. Conclusions: The findings of this study underscore the importance of considering the level of positive affect when examining the impact of moderate physical activity on cognitive performance in women with fibromyalgia.

CACNA1B protects naked mole-rat hippocampal neuron from apoptosis via altering the subcellular localization of Nrf2 after 60Co irradiation

Although radiotherapy is the most effective treatment modality for brain tumors, it always injures the central nervous system, leading to potential sequelae such as cognitive dysfunction. Radiation induces molecular, cellular, and functional changes in neuronal and glial cells. The hippocampus plays a critical role in learning and memory; therefore, concerns about radiation-induced injury are widespread. Multiple studies have focused on this complex problem, but the results have not been fully elucidated. Naked mole rat brains were irradiated with 60Co at a dose of 10 Gy. On 7 days, 14 days, and 28 days after irradiation, hippocampi in the control groups were obtained for next-generation sequencing. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were subsequently performed. Venn diagrams revealed 580 differentially expressed genes (DEGs) that were common at different times after irradiation. GO and KEGG analyses revealed that the 580 common DEGs were enriched in molecular transducer activity. In particular, CACNA1B mediated regulatory effects after irradiation. CACNA1B expression increased significantly after irradiation. Downregulation of CACNA1B led to a reduction in apoptosis and reactive oxygen species levels in hippocampal neurons. This was due to the interaction between CACNA1B and Nrf2, which disturbed the normal nuclear localization of Nrf2. In addition, CACNA1B downregulation led to a decrease in the cognitive functions of naked mole rats. These findings reveal the pivotal role of CACNA1B in regulating radiation-induced brain injury and will lead to the development of a novel strategy to prevent brain injury after irradiation.

The effect of crocin-selenium nanoparticles on the cognition and oxidative stress markers of multiple sclerosis patients: a randomized triple-blinded placebo-controlled clinical trial

The prevalence of cognitive impairment in multiple sclerosis (MS) patients is estimated to be approximately 40-60%. There is an increasing body of evidence regarding the impact of both selenium and crocin as antioxidant agents on cognitive function. In the present study, for the first time, we investigated the effect of crocin-selenium nanoparticles (Cor@SeNs) on cognitive function and oxidative stress markers in MS patients. A triple-blind randomized clinical trial was conducted among 60 MS patients. The participants were randomly divided in a 1:1 ratio to either the Cor@SeNs or placebo group, employing block randomization. During the course of 12 weeks, the participants received Cor@SeNs capsules, containing 5.74 mg crocin and 55 mcg Selenium, or placebo capsules. Cognition assessed using the Persian version of the Brief International Cognitive Assessment for MS (BICAMS) battery. Serum levels of total antioxidant capacity (TAC), glutathione reductase (GR) activity and malondialdehyde (MDA) determined by colorimetric kits. Data analysis was performed in SPSS, version 26. P < 0.05 was considered as the significant range. The mean ± SD of TAC change was 0.03 ± 0.07 mM vs. - 0.03 ± 0.09 mM in intervention and placebo groups, respectively (Time × group effect P: 0.01; effect size: 0.10). The time effect of intervention on the California Verbal Learning Test second edition (CVLT-II) (P < 0.01; effect size: 0.29), CVLT-II-delay (P < 0.01; effect size: 0.29), and the Symbol Digit Modalities Test (SDMT) (P < 0.01; effect size: 0.18) was increasing and significant. In addition, the time effect of intervention on GR activity was significant and decreasing in both groups (P < 0.01; effect size: 0.20). Our results suggested a significant effect of the Cor@SeNs intervention in improving TAC. We also observed a significant improvement in cognitive function in both groups during our study. However, although not statistically significant, a higher amount of change in cognitive function and serum antioxidant markers was noted in the Cor@SeNs group compared to the placebo group. This is the first study on this nano product with low dose of selenium and crocin. More investigations with longer duration and varied doses are suggested.

Reliability and Validity of the Spanish Adaptation of the Stanford Proxy Test for Delirium in Two Clinical Spanish-Speaking Communities

BACKGROUND

Delirium is the most prevalent neuropsychiatric syndrome experienced by patients admitted to inpatient clinical units, occurring in at least 20% of medically hospitalized patients and up to 85% of those admitted to critical care units. Although current guidelines recommend the implementation of universal prevention strategies, the use of management strategies largely depends on constant surveillance and screening. This allows for the timely diagnosis and correction of its underlying causes and implementation of management strategies.

OBJECTIVE

It was to adapt and analyze the Spanish adaptation of the Stanford Proxy Test for Delirium (S-PTDsv) instrument for its use among Spanish-speaking populations. The S-PTD is an instrument consisting of 13 observational items to be completed by a clinician observer, usually the patient's nurse. The completion of the questionnaire takes about 1 minute and does not require the active participation of the person evaluated, which has important clinical advantages compared to other available instruments (e.g., the Confusion Assessment Method).

METHODS

The psychometric properties of the S-PTDsv were evaluated in a population of 123 patients using a quantitative, cross-sectional design. All subjects were over 18 years of age and hospitalized in various inpatient medico-surgical and intensive care unit services, either at the Barcelona Clinical Hospital (Barcelona, Spain) or the UC-Christus Health Network Clinical Hospital (Santiago, Chile, S.A.). The ultimate diagnosis of delirium was made by a member of the Psychiatry Consult Service by means of an independent neuropsychiatric evaluation based on the Fifth Edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria, published in 2013, which is the latest version of the diagnostic manual. All study tests were performed by study personnel who were blinded to each other's test results within an hour of each other.

RESULTS

In the receiver operator characteristic (ROC) curve analysis, the S-PTDsv demonstrated excellent classification qualities when compared with the DSM-5 as the classification reference standard. Using a cutoff point of ≥3, the S-PTDsv had a sensitivity of 94% and a specificity of 97%. The area under the curve indicator was equal to 0.95, suggesting the S-PTDsv has an excellent overall performance in accurately identifying cases of delirium. Accordingly, the S-PTDsv's positive predictive value = 0.93, and the negative predictive value = 0.97. The internal reliability measured with Cronbach's alpha was 0.96. Confirmatory factor analysis revealed a 1-dimensional structure with high loadings (>0.72), demonstrating that all items similarly contribute to the total diagnostic dimension, suggesting adequate construct validity. This provided evidence of convergent validity.

CONCLUSIONS

The performance of the S-PTDsv, as compared to a blinded neuropsychiatric assessment based on DSM-5, indicates that it is an effective instrument for the detection of delirium, in the Spanish-speaking populations. These results are comparable and consistent with previously published studies in the English language version.

Elevated Plasma Protein Carbonyl Concentration Is Associated with More Abnormal White Matter in People with HIV

Structural brain abnormalities, including those in white matter (WM), remain common in people with HIV (PWH). Their pathogenesis is uncertain and may reflect multiple etiologies. Oxidative stress is associated with inflammation, HIV, and its comorbidities. The post-translational carbonylation of proteins results from oxidative stress, and circulating protein carbonyls may reflect this. In this cross-sectional analysis, we evaluated the associations between protein carbonyls and a panel of soluble biomarkers of neuronal injury and inflammation in plasma (N = 45) and cerebrospinal fluid (CSF, n = 32) with structural brain MRI. The volume of abnormal WM was normalized for the total WM volume (nAWM). In this multisite project, all regression models were adjusted for the scanner. The candidate covariates included demographics, HIV disease characteristics, and comorbidities. Participants were PWH on virally suppressive antiretroviral therapy (ART) and were mostly white (64.4%) men (88.9%), with a mean age of 56.8 years. In unadjusted analyses, more nAWM was associated with higher plasma protein carbonyls (p = 0.002) and higher CCL2 (p = 0.045). In the adjusted regression models for nAWM, the association with plasma protein carbonyls remained significant (FDR p = 0.018). Protein carbonyls in plasma may be a valuable biomarker of oxidative stress and its associated adverse health effects, including within the central nervous system. If confirmed, these findings would support the hypothesis that reducing oxidative stress could treat or prevent WM injury in PWH.

Low levels of peripheral blood activated and senescent T cells characterize people with HIV-1-associated neurocognitive disorders

Background

HIV infection induces a 75% increase in the risk of developing neurocognitive impairment (NCI), which has been linked to immune activation. We therefore looked for immune activation markers correlating with NCI.

Method

Sixty-five people aged 55-70 years living with controlled HIV-1 infection were enrolled in the study and their neurocognitive ability was assessed according to the Frascati criteria. Fifty-nine markers of T4 cell, T8 cell, NK cell, and monocyte activation, inflammation and endothelial activation were measured in their peripheral blood. White matter hyperintensities (WMH) were identified by magnetic resonance imaging. Double hierarchical clustering was performed for the activation markers and 240 patients including the 65 whose neurocognitive performance had been evaluated.

Results

Thirty-eight percent of volunteers presented NCI. Twenty-four percent of them were asymptomatic and fourteen percent had a mild disorder. Strikingly, activated (HLA-DR+) as well as senescent (CD57+CD28-CD27±) T4 cells and T8 cells were less prevalent in the peripheral blood of participants with NCI than in participants without the disorder. Accordingly, the percentage of HLA-DR+ T4 cells was lower in volunteers with periventricular and deep WMH. The double hierarchical clustering unveiled six different immune activation profiles. The neurocognitive performances of participants with two of these six profiles were poor. Here again, these two profiles were characterized by a low level of T4 and T8 cell activation and senescence.

Conclusion

Our observation of low circulating levels of activated and senescent T cells in HIV-1 patients with NCI raises the interesting hypothesis that these lymphocytes may be recruited into the central nervous system.

Lipid mediators of cerebrospinal fluid in response to TBE and bacterial co-infections

Tick-borne diseases are caused by monoinfection or co-infection with different pathogens, including viruses, bacteria and protozoa. Tick-borne diseases are usually accompanied by oxidative stress which promotes the modifications of the host's lipid metabolism. The aim of the study was to compare total antioxidant status and the level of lipid mediators in the cerebrospinal fluid in response to tick-borne encephalitis (TBE) and bacterial co-infections that cause diseases such as that is Lyme borreliosis (LB) and human granulocytic anaplasmosis (HGA). In our study cerebrospinal fluid samples were obtained from 15 patients with TBE and 6 patients with TBE co-infection with LB and/or HGA at admission and after treatment. Control group consisted of 14 patients in whom meningitis was excluded. Total antioxidant status, levels of lipid peroxidation products, endocannabinoids and eicosanoids (determined by liquid and gas chromatography-mass spectrometry) were compared between the groups. It was found that in TBE patients, total antioxidant status was decreased and accompanied by increased levels of lipid peroxidation products (4-HNE, MDA, isoprostanes and neuroprostanes), major endocannabinoids (AEA and 2AG), and eicosanoids (both anti-inflammatory and pro-inflammatory), which generally declined after treatment. On the other hand, in co-infections, significant changes in the levels of some lipid mediators were observed even after the treatment. TBE alone or along with bacterial co-infections promote redox balance disturbances in the cerebrospinal fluid leading to oxidative stress and increased metabolism of phospholipids in the brain tissue reflected in the level of lipid peroxidation products and lipid mediators. Changes in the level of lipid mediators in patients with co-infections after treatment suggest further intensification of metabolic disturbances rather than their resolution.

Long Non-Coding RNAs, Extracellular Vesicles and Inflammation in Alzheimer's Disease

Alzheimer's Disease (AD) has currently no effective treatment; however, preventive measures have the potential to reduce AD risk. Thus, accurate and early prediction of risk is an important strategy to alleviate the AD burden. Neuroinflammation is a major factor prompting the onset of the disease. Inflammation exerts its toxic effect via multiple mechanisms. Amongst others, it is affecting gene expression via modulation of non-coding RNAs (ncRNAs), such as miRNAs. Recent evidence supports that inflammation can also affect long non-coding RNA (lncRNA) expression. While the association between miRNAs and inflammation in AD has been studied, the role of lncRNAs in neurodegenerative diseases has been less explored. In this review, we focus on lncRNAs and inflammation in the context of AD. Furthermore, since plasma-isolated extracellular vesicles (EVs) are increasingly recognized as an effective monitoring strategy for brain pathologies, we have focused on the studies reporting dysregulated lncRNAs in EVs isolated from AD patients and controls. The revised literature shows a positive association between pro-inflammatory lncRNAs and AD. However, the reports evaluating lncRNA alterations in EVs isolated from the plasma of patients and controls, although still limited, confirm the value of specific lncRNAs associated with AD as reliable biomarkers. This is an emerging field that will open new avenues to improve risk prediction and patient stratification, and may lead to the discovery of potential novel therapeutic targets for AD.

Postoperative Delirium in Neurosurgical Patients: Recent Insights into the Pathogenesis

Postoperative delirium (POD) is a complication characterized by disturbances in attention, awareness, and cognitive function that occur shortly after surgery or emergence from anesthesia. Since it occurs prevalently in neurosurgical patients and poses great threats to the well-being of patients, much emphasis is placed on POD in neurosurgical units. However, there are intricate theories about its pathogenesis and limited pharmacological interventions for POD. In this study, we review the recent insights into its pathogenesis, mainly based on studies within five years, and the five dominant pathological theories that account for the development of POD, with the intention of furthering our understanding and boosting its clinical management.