The Interplay Between Neuroinfections, the Immune System and Neurological Disorders: A Focus on Africa

Emerging Trends: Neurofilament Biomarkers in Precision Neurology

Neurofilaments are structural proteins found in the cytoplasm of neurons, particularly in axons, providing structural support and stability to the axon. They consist of multiple subunits, including NF-H, NF-M, and NF-L, which form long filaments along the axon's length. Neurofilaments are crucial for maintaining the shape and integrity of neurons, promoting axonal transport, and regulating neuronal function. They are part of the intermediate filament (IF) family, which has approximately 70 tissue-specific genes. This diversity allows for a customizable cytoplasmic meshwork, adapting to the unique structural demands of different tissues and cell types. Neurofilament proteins show increased levels in both cerebrospinal fluid (CSF) and blood after neuroaxonal damage, indicating injury regardless of the underlying etiology. Precise measurement and long-term monitoring of damage are necessary for determining prognosis, assessing disease activity, tracking therapeutic responses, and creating treatments. These investigations contribute to our understanding of the importance of proper NF composition in fundamental neuronal processes and have implications for neurological disorders associated with NF abnormalities along with its alteration in different animal and human models. Here in this review, we have highlighted various neurological disorders such as Alzheimer's, Parkinson's, Huntington's, Dementia, and paved the way to use neurofilament as a marker in managing neurological disorders.

Navigating Challenges and Embracing Opportunities: The Outlook of Functional Neurosurgery in Africa

This narrative review explores the current landscape of functional neurosurgery in Africa, focusing on the challenges and opportunities facing the field. Drawing upon existing literature and expert insights, the review highlights the scarcity of resources, including trained personnel, infrastructure, and specialized equipment, as major hurdles impeding the widespread adoption of advanced neurosurgical techniques. Despite these challenges, the review identifies a growing recognition of the importance of functional neurosurgery in addressing neurological disorders prevalent across the continent. Efforts to enhance training programs, establish collaborations with international partners, and leverage technology are discussed as promising strategies to overcome logistical barriers. Moreover, the review underscores the significance of addressing cultural beliefs and stigmas surrounding neurological conditions to ensure equitable access to care and promote acceptance of neurosurgical interventions. By navigating these challenges and embracing emerging opportunities, functional neurosurgery in Africa holds the potential to significantly impact neurological health outcomes and enhance overall well-being.

Characteristic Profiling of Soluble Factors in the Cerebrospinal Fluid of Patients With Neurosyphilis

BACKGROUND

Soluble inflammatory factors in the cerebrospinal fluid (CSF) of patients with neurosyphilis have been investigated with low-throughput technology. This study aimed to illustrate the characteristics of soluble factor profiles in CSF of patients with neurosyphilis.

METHODS

We measured the concentrations of 45 cytokines, chemokines, and growth factors in CSF from 112 untreated syphilis cases, including latent syphilis (LS), asymptomatic neurosyphilis (ANS), meningeal neurosyphilis (MNS), meningovascular neurosyphilis (MVNS), paralytic dementia (PD), and ocular syphilis (OS).

RESULTS

Thirty-three differentially expressed soluble factors (DeSFs) were categorized into 3 clusters. DeSF scores of clusters 1 and 2 (DeSFS1 and DeSFS2) were positively correlated with elevated neopterin and neurofilament light subunit (NF-L) concentration, respectively. DeSF scores of cluster 3 were positively correlated with white blood cells, protein, NF-L, and neopterin. Patients with LS, ANS, and OS exhibited an overall lower abundance of DeSFs. Patients with PD exhibited significantly increased levels of clusters 1 and 3, and the highest total DeSF score, whereas patients with MNS and MVNS showed enhanced levels of cluster 2. Receiver operating characteristic analysis revealed that DeSFS1 effectively discriminated PD, and DeSFS2 discriminated MNS/MVNS with high accuracy.

CONCLUSIONS

Patients with neurosyphilis at different stages have distinctive patterns of soluble factors in CSF, which are correlated with immune status and neuronal damage.

Geriatric nutritional risk index has a prognostic value for recovery outcomes in elderly patients with brain abscess

Background

The Geriatric Nutritional Risk Index (GNRI) is a straightforward and objective tool for nutritional screening in older patients and has been demonstrated to possess prognostic predictive value in several diseases. Nonetheless, there is a lack of research on the nutritional risk associated with brain abscess in the older. This study aimed to evaluate the prevalence of nutritional risk among these patients by GNRI and to investigate its potential prognostic value for clinical outcomes.

Materials and methods

From August 2019 to April 2023, 100 older patients diagnosed with brain abscess were enrolled in this single-center prospective cohort study, which evaluated the prognostic value of the Geriatric Nutritional Risk Index (GNRI) in elderly brain abscess patients. Data collected included demographic, and clinical characteristics at admission and calculated the GNRI, and the Glasgow Outcome Scale (GOS) score 6 months post-discharge. A GOS score of 5 was considered indicative of a good recovery, whereas scores ranging from 1 to 4 were classified as poor recovery.

Results

The results revealed that 48% of older brain abscess patients were at risk of malnutrition according to the GNRI. These patients had significantly higher post-admission C-reactive protein (CRP) levels (p = 0.017), more comorbidities (p < 0.001), and higher age-adjusted Charlson Comorbidity Index (aCCI) scores (p < 0.001) compared to those without nutritional risk. Spearman correlation analysis showed that GNRI scores were negatively correlated with CRP levels, comorbidities, and aCCI scores, and positively correlated with Glasgow Outcome Scale (GOS) scores (Spearman's ρ = 0.624, p < 0.001). Multivariate logistic regression revealed that lower GNRI values were linked to reduced GOS levels (OR = 0.826, 95% CI: 0.775-0.880). ROC analysis determined a GNRI threshold of 97.50 for predicting poor recovery, with 90.57% sensitivity and 87.23% specificity.

Conclusion

The older brain abscess patients exhibited a high malnutrition risk. GNRI showed an important predictive value for recovery in older patients, which could be helpful in clinical intervention and rehabilitation.

Neurological manifestations of Flaviviridae, Togaviridae, and Peribunyaviridae as vector-borne viruses

Vector-borne viruses pose a significant health problem worldwide, as they are transmitted to humans through the bite of infected arthropods such as mosquitoes and ticks. In recent years, emerging and re-emerging vector-borne diseases have gained attention as they can cause a wide spectrum of neurological manifestations. The neurological manifestations of vector-borne viruses encompass a board spectrum of clinical manifestations, ranging from mild and self-limiting symptoms to severe and life-threatening conditions. Common neurological complications include viral encephalitis, acute flaccid paralysis, aseptic meningitis, and various neuromuscular disorders. The specific viruses responsible for these neurological sequelae vary by geographic region and include Orthoflavivirus nilense, Zika virus, dengue virus, chikungunya virus, Japanese encephalitis virus, and tick-borne encephalitis virus. This review focuses on the pathogenesis of these neurologic complications and highlights the mechanisms by which vector-borne viruses invade the central nervous system and trigger neuroinflammatory responses. Diagnostic challenges and strategies for early detection of neurological manifestations are discussed, emphasising the importance of clinical suspicion and advanced laboratory testing.

Diet composition and sterilization modifies intestinal microbiome diversity and burden of Theiler's virus infection-induced acute seizures

OBJECTIVE

Brain infection with Theiler's murine encephalomyelitis virus (TMEV) in C57BL/6J mice can induce acquired epileptogenesis. Diet alters acute seizure incidence in TMEV-infected mice; yet it is unclear whether intestinal dysbiosis may also impact acute or chronic behavioral comorbidities. This study thus assessed the impact of diet formulation and sterilization on acute seizure presentation, gut microbiome composition, and epilepsy-related chronic behavioral comorbidities.

METHODS

Baseline fecal samples were collected from male C57BL/6J mice (4- to 5-weeks-old; Jackson Labs) upon facility arrival. Mice were randomized to either autoclaved (AC) or irradiated diet (IR) (Prolab RMH 3000) or IR (Picolab 5053). Three days later, mice underwent intracerebral TMEV or phosphate-buffered saline (PBS) injection. Fecal samples were collected from a subset of mice at infection (Day 0) and Day 7 post-infection. Epilepsy-related working memory deficits and seizure threshold were assessed 6 weeks post-infection. Gut microbiome diversity was determined by 16S rRNA amplicon sequencing of fecal samples.

RESULTS

TMEV-infected mice displayed acute handling-induced seizures, regardless of diet: 28 of 57 IR Picolab 5053 (49.1%), 30 of 41 IR Prolab RMH 3000 (73.2%), and 47 of 77 AC Prolab RMH 3000 (61%) mice displayed seizures. The number of observed seizures differed significantly by diet: IR Picolab 5053 diet-fed mice had 2.2 ± 2.8 seizures (mean ± standard deviation), IR Prolab RMH 3000 diet-fed mice had 3.5 ± 2.9 seizures, and AC Prolab RMH 3000 diet-fed mice had 4.4 ± 3.8 seizures during the 7-day monitoring period. Gut microbiome composition differed significantly in TMEV-infected mice fed the AC Prolab RMH 3000 diet, with measured differences in gram-positive bacteria. These mice also displayed worsened long-term working memory deficits.

SIGNIFICANCE

Diet-induced differences in intestinal dysbiosis in the TMEV model are associated with marked changes in acute seizure presentation, symptomatic recovery, and onset of chronic behavioral comorbidities of epilepsy. Our study reveals a novel disease-modifying impact of dietary manipulation on intestinal bacterial species after TMEV-induced acute seizures.

The landscape of neuroscience research in Africa: current state, progress, and challenges; a perspective

The field of neuroscience research in Africa has witnessed significant advancements in recent years, contributing to understanding the brain and neurological disorders. This paper provides an overview of the current state of neuroscience research in Africa, highlighting the progress made, ongoing efforts, and the challenges researchers face. Despite limited resources and funding constraints, African scientists have made remarkable strides in various areas of neuroscience. Collaborative networks and international partnerships have been crucial in advancing education, research infrastructure, and capacity building in the field. Institutions in countries such as Egypt, Ghana, South Africa, Nigeria, Tunisia, and Morocco have emerged as key hubs for neuroscience research, fostering a growing community of researchers dedicated to unravelling the complexities of the brain. Efforts in neuroscience research have encompassed diverse domains, including neurogenomics, neuroimaging, neurophysiology, neurorehabilitation, and neuroepidemiology. Studies have focused on investigating genetic factors underlying neurological conditions, exploring the neural mechanisms of cognition and behaviour, and developing innovative therapeutic approaches for neurological disorders. However, challenges persist in the African neuroscience research landscape. Limited funding remains a significant barrier, hindering the establishment of well-equipped laboratories, access to advanced technologies, and support for research projects. Addressing these concerns is crucial to ensure research outcomes' integrity, validity, and relevance. Looking ahead, strategic interventions are required to address these challenges and further advance neuroscience research in Africa.

Secondary headache disorders in Turkey, the Middle East, Asia, and Africa: A cross-sectional, multicenter study

BACKGROUND

This multicenter cross-sectional study aimed to determine the frequency and characteristics of secondary headaches in different geographic regions, including Turkey, the Middle East, Asia, and Africa.

METHODS

Patients were admitted to the study on a particular day each week for five consecutive weeks between 1 April and 16 May 2022. Before the study, all researchers underwent a constructed briefing about the use and code of the ICHD-3 criteria. The study was conducted in two stages. In the first stage, data on secondary headaches were compared between the regions. In the second stage, the sub-diagnoses of secondary headaches were analyzed only in Turkey.

RESULTS

A total of 4144 (30.0%) of the 13,794 patients reported headaches as the main symptoms at admission. A total of 422 patients were excluded from the study. In total, 1249 (33.4%) of 3722 patients were diagnosed as having secondary headaches (Turkey [n = 1039], Middle East [n = 80], Asia [n = 51], Africa [n = 79]). The frequency of secondary headaches (Turkey 33.6%, Africa 30.1%, Middle East 35.5%, Asia 35.4%) did not differ significantly between the regions (p > 0.05). The most common subtype of secondary headaches was headache attributed to substances or their withdrawal in all the studied regions. There was a female predominance in all regions, but it was lower in Africa than in Turkey. The severity and density of headaches differed significantly between the regions, with patients from Africa reporting milder pain than patients from other regions. In Turkey, the most common sub-diagnoses of secondary headaches were medication overuse headache, idiopathic intracranial hypertension, and cervicogenic headache.

CONCLUSION

In the present study, one in three patients with a headache had a secondary headache. Headache attributed to substances or their withdrawal was the most common subtype of secondary headaches in all the studied regions. The female predominance of secondary headaches was lower in Africa than in Turkey. The severity and density of headaches differed significantly between regions, with patients from Africa reporting milder pain.

Evidence of Immunomodulatory Food-Protein Derived Peptides in Human Nutritional Interventions: Review on the Outcomes and Potential Limitations

The immune system is somehow related to all the metabolic pathways, in a bidirectional way, and the nutritional interventions affecting these pathways might have a relevant impact on the inflammatory status of the individuals. Food-derived peptides have been demonstrated to exert several bioactivities by in vitro or animal studies. Their potential to be used as functional food is promising, considering the simplicity of their production and the high value of the products obtained. However, the number of human studies performed until now to demonstrate effects in vivo is still scarce. Several factors must be taken into consideration to carry out a high-quality human study to demonstrate immunomodulatory-promoting properties of a test item. This review aims to summarize the recent human studies published in which the purpose was to demonstrate bioactivity of protein hydrolysates, highlighting the main results and the limitations that can restrict the relevance of the studies. Results collected are promising, although in some studies, physiological changes could not be observed. When responses were observed, they sometimes did not refer to relevant parameters and the immunomodulatory properties could not be clearly established with the current evidence. Well-designed clinical trials are needed in order to evaluate the role of protein hydrolysates in immunonutrition.

Sleep-Disturbance-Induced Microglial Activation Involves CRH-Mediated Galectin 3 and Autophagy Dysregulation

Chronic sleep disturbances (CSDs) including insomnia, insufficient sleep time, and poor sleep quality are major public health concerns around the world, especially in developed countries. CSDs are major health risk factors linked to multiple neurodegenerative and neuropsychological diseases. It has been suggested that CSDs could activate microglia (Mg) leading to increased neuroinflammation levels, which ultimately lead to neuronal dysfunction. However, the detailed mechanisms underlying CSD-mediated microglial activation remain mostly unexplored. In this study, we used mice with three-weeks of sleep fragmentation (SF) to explore the underlying pathways responsible for Mg activation. Our results revealed that SF activates Mg in the hippocampus (HP) but not in the striatum and prefrontal cortex (PFc). SF increased the levels of corticotropin-releasing hormone (CRH) in the HP. In vitro mechanism studies revealed that CRH activation of Mg involves galectin 3 (Gal3) upregulation and autophagy dysregulation. CRH could disrupt lysosome membrane integrity resulting in lysosomal cathepsins leakage. CRHR2 blockage mitigated CRH-mediated effects on microglia in vitro. SF mice also show increased Gal3 levels and autophagy dysregulation in the HP compared to controls. Taken together, our results show that SF-mediated hippocampal Mg activation involves CRH mediated galectin 3 and autophagy dysregulation. These findings suggest that targeting the hippocampal CRH system might be a novel therapeutic approach to ameliorate CSD-mediated neuroinflammation and neurodegenerative diseases.

Caregiver's perspectives on the Central Nervous System infection illness trajectory among older persons with dementia in Northern Uganda-a qualitative community-based study

BACKGROUND

Few studies have explored the Central Nervous System (CNS) infection illness trajectory among older persons with dementia in sub-Saharan African (SSA) settings. This study explored the Caregiver's perspectives on the Central Nervous System infection illness trajectory among the older persons with dementia in Northern Uganda.

METHODS

This was a qualitative study conducted in Lira District northern Uganda in March 2022 amongst purposively selected 20 caregivers of the older persons aged 50 + years with a positive history of CNS infection and later life dementia. Data were collected using an in-depth interview guide. Audio recordings and field notes of the interviews were undertaken. The interviews generated data on the CNS infection illness trajectory from onset to the current demented state of the older persons. The audio-recorded interviews were transcribed verbatim before manual reflective thematic analysis.

RESULTS

Older persons with a positive history of CNS infection illness and later life dementia in rural northern Uganda presented with symptoms of early life CNS infection illness ranging from neck pain, back pain, chronic headache, and fatigue. There were also manifestations of comorbidities particularly road traffic accidents involving traumatic injury to the head, neck, and spine, high blood pressure, chronic headache, and or their medications in the older person's trajectory to later life dementia. A plurality of healthcare which included both formal and informal healthcare medicines was sought and utilized for the treatment and care of the CNS infection illness and dementia by the older persons amidst improper diagnosis and mismanagement.

CONCLUSIONS AND RECOMMENDATIONS

Older persons with early-life CNS infections illness and later-life dementia were reported to present with symptoms including neck pain, back pain, chronic headache, high blood pressure, and fatigue. The reported symptoms of CNS infection illness may be intertwined with co-morbidities particularly traumatic injury involving the head, neck, and spine, high blood pressure, and chronic headache. Healthcare professionals should integrate routine screening of older persons for the history of CNS infections, chronic headache, high blood pressure, trauma to the head, neck, and spine, and dementia and early treatment.

Serum Cytokines Predict Neurological Damage in Genetically Diverse Mouse Models

Viral infections contribute to neurological and immunological dysfunction driven by complex genetic networks. Theiler's murine encephalomyelitis virus (TMEV) causes neurological dysfunction in mice and can model human outcomes to viral infections. Here, we used genetically distinct mice from five Collaborative Cross mouse strains and C57BL/6J to demonstrate how TMEV-induced immune responses in serum may predict neurological outcomes in acute infection. To test the hypothesis that serum cytokine levels can provide biomarkers for phenotypic outcomes of acute disease, we compared cytokine levels at pre-injection, 4 days post-injection (d.p.i.), and 14 d.p.i. Each strain produced unique baseline cytokine levels and had distinct immune responses to the injection procedure itself. Thus, we eliminated the baseline responses to the injection procedure itself and identified cytokines and chemokines induced specifically by TMEV infection. Then, we identified strain-specific longitudinal cytokine profiles in serum during acute disease. Using stepwise regression analysis, we identified serum immune markers predictive for TMEV-induced neurological phenotypes of the acute phase, e.g., IL-9 for limb paralysis; and TNF-α, IL-1β, and MIP-1β for limb weakness. These findings indicate how temporal differences in immune responses are influenced by host genetic background and demonstrate the potential of serum biomarkers to track the neurological effects of viral infection.

Sleep Disturbance Alters Cocaine-Induced Locomotor Activity: Involvement of Striatal Neuroimmune and Dopamine Signaling

Sleep disorders have high comorbidity with drug addiction and function as major risk factors for developing drug addiction. Recent studies have indicated that both sleep disturbance (SD) and abused drugs could activate microglia, and that increased neuroinflammation plays a critical role in the pathogenesis of both diseases. Whether microglia are involved in the contribution of chronic SDs to drug addiction has never been explored. In this study, we employed a mouse model of sleep fragmentation (SF) with cocaine treatment and examined their locomotor activities, as well as neuroinflammation levels and dopamine signaling in the striatum, to assess their interaction. We also included mice with, or without, SF that underwent cocaine withdrawal and challenge. Our results showed that SF significantly blunted cocaine-induced locomotor stimulation while having marginal effects on locomotor activity of mice with saline injections. Meanwhile, SF modulated the effects of cocaine on neuroimmune signaling in the striatum and in ex vivo isolated microglia. We did not observe differences in dopamine signaling in the striatum among treatment groups. In mice exposed to cocaine and later withdrawal, SF reduced locomotor sensitivity and also modulated neuroimmune and dopamine signaling in the striatum. Taken together, our results suggested that SF was capable of blunting cocaine-induced psychoactive effects through modulating neuroimmune and dopamine signaling. We hypothesize that SF could affect neuroimmune and dopamine signaling in the brain reward circuitry, which might mediate the linkage between sleep disorders and drug addiction.