Debate: CAMHS will be at the forefront of the next generation of psychosis risk models, but further integration with early intervention psychosis services is needed to realise this potential: Re Debate: Prevention of psychosis in adolescents - does CAMHS have a role?

The detection of psychosis and its prodrome have unique considerations in a child and adolescent population. Young people attending CAMHS are already a high-risk group, which confers significant limitations in applying the current clinical high-risk (CHR) model. This has catalysed calls for a transdiagnostic approach to psychosis risk prediction, but without a clear pathway forward. We contribute to the debate opened by Salazar de Pablo and Arango (2023, Child and Adolescent Mental Health) on the role of CAMHS in this initiative. CAMHS have a key role in developing comprehensive longitudinal datasets to inform risk models. Closer integration with early intervention in psychosis (EIP) services will be needed to realise this potential. This integration is also required to reliably detect prodromes and emerging psychosis in young people. Where there is robust evidence to support prevention initiatives, we should proceed with their implementation, even in the absence of enhanced risk models.

Rab43 GTPase directs postsynaptic trafficking and neuron-specific sorting of G protein-coupled receptors.

G protein-coupled receptors (GPCRs) are important modulators of synaptic functions. A fundamental but poorly addressed question in neurobiology is how targeted GPCR trafficking is achieved. Rab GTPases are the master regulators of vesicle-mediated membrane trafficking, but their functions in the synaptic presentation of newly synthesized GPCRs are virtually unknown. Here, we investigate the role of Rab43, via dominant-negative inhibition and CRISPR-Cas9-mediated KO, in the export trafficking of α2-adrenergic receptor (α2-AR) and muscarinic acetylcholine receptor (mAChR) in primary neurons and cells. We demonstrate that Rab43 differentially regulates the overall surface expression of endogenous α2-AR and mAChR, as well as their signaling, in primary neurons. In parallel, Rab43 exerts distinct effects on the dendritic and postsynaptic transport of specific α2B-AR and M3 mAChR subtypes. More interestingly, the selective actions of Rab43 toward α2B-AR and M3 mAChR are neuronal cell specific and dictated by direct interaction. These data reveal novel, neuron-specific functions for Rab43 in the dendritic and postsynaptic targeting and sorting of GPCRs and imply multiple forward delivery routes for different GPCRs in neurons. Overall, this study provides important insights into regulatory mechanisms of GPCR anterograde traffic to the functional destination in neurons.

Marrow changes and reduced proliferative capacity of mesenchymal stromal cells from patients with "no-option" critical limb ischemia; observations on feasibility of the autologous approach from a clinical trial.

BACKGROUND AIMS: Approximately 1 in 3 patients with critical limb ischemia (CLI) are not suitable for surgical or endovascular revascularization. Those "no-option" patients are at high risk of amputation and death. Autologous bone marrow mesenchymal stromal cells (MSCs) may provide a limb salvage option. In this study, bone marrow characteristics and expansion potentials of CLI-derived MSCs produced during a phase 1b clinical trial were compared with young healthy donor MSCs to determine the feasibility of an autologous approach. Cells were produced under Good Manufacturing Practice conditions and underwent appropriate release testing. METHODS: Five bone marrow aspirates derived from patients with CLI were compared with six young healthy donor marrows in terms of number of colony-forming units-fibroblast (CFUF) and mononuclear cells. The mean population doubling times and final cell yields were used to evaluate expansion potential. The effect of increasing the volume of marrow on the CFUF count and final cell yield was evaluated by comparing 5 CLI-derived MSCs batches produced from a targeted 30 mL of marrow aspirate to five batches produced from a targeted 100 mL of marrow. RESULTS: CLI-derived marrow aspirate showed significantly lower numbers of mononuclear cells with no difference in the number of CFUFs when compared with healthy donors' marrow aspirate. CLI-derived MSCs showed a significantly longer population doubling time and reduced final cell yield compared with young healthy donors' MSCs. The poor growth kinetics of CLI MSCs were not mitigated by increasing the bone marrow aspirate from 30 to 100 mL. CONCLUSIONS: In addition to the previously reported karyotype abnormalities in MSCs isolated from patients with CLI, but not in cells from healthy donors, the feasibility of autologous transplantation of bone marrow MSCs for patients with no-option CLI is further limited by the increased expansion time and the reduced cell yield.

Psychiatric training in perinatal mental health across Europe.

Perinatal mental illness is associated with considerable maternal and infant morbidity and mortality. However, there are currently no specific guidelines on the standards and structure of postgraduate perinatal psychiatric training in Europe. We describe the characteristics of available and desired specialist perinatal psychiatry training from the perspective of European psychiatrists in training. An online survey was conducted among 34 national psychiatric trainee association representatives of the European Federation of Psychiatric Trainees (EFPT). Participants from the countries in which perinatal psychiatry training was available were invited to participate in in-depth follow-up interviews. Six countries out of 34 (18%) reported that specialist training in perinatal mental health was available (Finland, France, Germany, Ireland, Malta, and the UK). The nature of available training varied in duration, the supervision and assessment model employed, and the training scheme context. Of the 28 countries where specialist perinatal psychiatry training was unavailable, the majority of national representatives (22 countries, 76%) wanted specialist perinatal psychiatry training to be included in their national training curricula. There is a gap between the expected skills and the available training for psychiatrists to meet the mental healthcare needs of women in the perinatal period. Given the prevalence and impact of perinatal mental illness and the expressed desires of trainees themselves for specialist training, this finding should prompt urgent action.

Autologous bone marrow mesenchymal stromal cell therapy for "no-option" critical limb ischemia is limited by karyotype abnormalities.

BACKGROUND: Critical limb ischemia (CLI) is the most severe manifestation of peripheral vascular disease. Revascularization is the preferred therapy, but it is not achievable in 25%-40% of patients due to diffuse anatomic distribution of the disease or medical comorbidities. No-option CLI represents an unmet medical need. Mesenchymal stromal cells (MSCs) may provide salvage therapy through their angiogenic and tissue-trophic properties. This article reports a phase 1b clinical study examining the safety and feasibility of intramuscular transplantation of autologous bone-marrow MSCs for patients with no-option CLI. METHODS: Twelve patients were enrolled in the clinical trial, and nine proceeded to bone marrow aspiration and culture expansion of MSCs. RESULTS: A high rate of karyotype abnormality (>30%) was detected in the produced cell batches, resulting in failure of release for clinical administration. Four patients were treated with the investigational medicinal product (IMP), three with a low dose of 20 × 106 MSCs and one with a mid-dose of 40 × 106 MSCs. There were no serious adverse events related to trial interventions, including bone marrow aspiration, IMP injection or therapy. CONCLUSIONS: The results of this trial conclude that an autologous cell therapy approach with MSCs for critical limb ischemia is limited by the high rate of karyotype abnormalities.

Mass Spectrometric Quantitation of Tubulin Acetylation from Pepsin-Digested Rat Brain Tissue Using a Novel Stable-Isotope Standard and Capture by Anti-Peptide Antibody (SISCAPA) Method.

Acetylation of α-tubulin at Lys-40 is a potential biomarker for cognitive deficits in various neurological disorders. However, this key post-translational modification (PTM) has not been previously studied with mass spectrometry, due to the inadequate distribution of tryptic cleavage sites. Following peptic digestion, a surrogate sequence containing this key PTM site was identified and was found to be stable and quantitatively reproducible. A highly sensitive and specific SISCAPA-LC-MS method for quantitating rat brain tubulin acetylation was developed, validated, and applied, and only required a small amount of tissue (2.2 mg). This workflow includes peptic digestion, stable-isotope dilution, capture with antiacetylated peptide antibody bound on protein G beads, and quantitation using LC-MS. The method allowed a lower limit of quantitation at 2.50 pmol/mg and provided a linear range of 2.50-62.50 pmol/mg. Selectivity, intra and interday precision and accuracy were also validated. This method has been successfully applied in a preclinical study of organophosphate neurotoxicity, and we found that chronic exposure to chlorpyrifos led to a significant and persistent inhibition of brain tubulin acetylation.

Diisopropylfluorophosphate Impairs the Transport of Membrane-Bound Organelles in Rat Cortical Axons.

The extensive use of organophosphates (OPs) is an ongoing environmental health concern due to multiple reports of OP-related neurologic abnormalities. The mechanism of the acute toxicity of OPs has been attributed to inhibition of acetylcholinesterase (AChE), but there is growing evidence that this may not account for all the long-term neurotoxic effects of OPs. In previous experiments (using ex vivo and in vitro model systems) we observed that the insecticide OP chlorpyrifos impaired the movements of vesicles and mitochondria in axons. Here, using a time-lapse imaging technique, we evaluated the OP-nerve agent diisopropylfluorophosphate (DFP) across a wide range of concentrations (subnanomolar to micromolar) for effects on fast axonal transport of membrane-bound organelles (MBOs) that contain the amyloid precursor protein (APP) tagged with the fluorescent marker Dendra2 (APPDendra2). Both 1 and 24 hours of exposure to DFP and a positive control compound, colchicine, resulted in a decrease in the velocity of anterograde and retrograde movements of MBOs and an increase in the number of stationary MBOs. These effects occurred at picomolar (100 pM) to low nanomolar (0.1 nM) concentrations that were not associated with compromised cell viability or cytoskeletal damage. Moreover, the effects of DFP on axonal transport occurred at concentrations that did not inhibit AChE activity, and they were not blocked by cholinergic receptor antagonists. Given the fundamental importance of axonal transport to neuronal function, these observations may explain some of the long-term neurologic deficits that have been observed in humans who have been exposed to OPs.

An exploratory study of psychosis risk factors in individuals who are referred but do not meet criteria for an early intervention in psychosis service.

BACKGROUND: The 'at-risk mental state' (ARMS) for psychosis has been critiqued for its limited prognostic ability and identification of a limited proportion of those who will develop a first episode of psychosis (FEP). Broadening the search for high-risk groups is key to improving population-level ascertainment of psychosis risk. AIMS: To explore risk enrichment in diagnostic, demographic and socio-functional domains among individuals referred to an early intervention in psychosis (EIP) service not meeting ARMS or FEP criteria. METHOD: A retrospective file review of 16 years of referrals to a tertiary EIP service in Ireland was undertaken. Diagnostic outcomes from standardised assessments (Structured Clinical Interview for DSM), demographic (age, gender, family history, nationality) and socio-occupational (relationship status, living status, working status) variables were compiled for those not meeting criteria. These were compared with individuals diagnosed with an FEP in the same period. RESULTS: From 2005 to 2021 inclusive, of 2025 index assessments, 27.6% (n = 558) did not meet either FEP or ARMS criteria, which is notably higher than the 5.4% (n = 110) meeting ARMS criteria. This group had high psychiatric morbidity, with 65.4% meeting criteria for at least one DSM Axis I disorder. Depressive, anxiety and substance use disorders predominated. Their functional markers were poor, and comparable to the FEP cohort. CONCLUSIONS: This group is enriched for psychosis risk factors. They are a larger group than those meeting ARMS criteria, a finding that may reflect EIP service configuration. They may be an important focus for further study in the search for at-risk populations beyond the current ARMS model.

Diminished trkA receptor signaling reveals cholinergic-attentional vulnerability of aging.

The cellular mechanisms underlying the exceptional vulnerability of the basal forebrain (BF) cholinergic neurons during pathological aging have remained elusive. Here we employed an adeno-associated viral vector-based RNA interference (AAV-RNAi) strategy to suppress the expression of tropomyosin-related kinase A (trkA) receptors by cholinergic neurons in the nucleus basalis of Meynert/substantia innominata (nMB/SI) of adult and aged rats. Suppression of trkA receptor expression impaired attentional performance selectively in aged rats. Performance correlated with trkA levels in the nMB/SI. trkA knockdown neither affected nMB/SI cholinergic cell counts nor the decrease in cholinergic cell size observed in aged rats. However, trkA suppression augmented an age-related decrease in the density of cortical cholinergic processes and attenuated the capacity of cholinergic neurons to release acetylcholine (ACh). The capacity of cortical synapses to release ACh in vivo was also lower in aged/trkA-AAV-infused rats than in aged or young controls, and it correlated with their attentional performance. Furthermore, age-related increases in cortical proNGF and p75 receptor levels interacted with the vector-induced loss of trkA receptors to shift NGF signaling toward p75-mediated suppression of the cholinergic phenotype, thereby attenuating cholinergic function and impairing attentional performance. These effects model the abnormal trophic regulation of cholinergic neurons and cognitive impairments in patients with early Alzheimer's disease. This rat model is useful for identifying the mechanisms rendering aging cholinergic neurons vulnerable as well as for studying the neuropathological mechanisms that are triggered by disrupted trophic signaling.

Post-CSCST fellowships: beyond subspecialization.

The transition from higher training to consultanthood is a crucial point in the medical training pathway. Despite comprehensive higher training programs, studies of new consultants have reported a disparity in their sense of preparation for non-clinical and clinical duties. Post- "Certificate of Satisfactory Completion of Specialist Training" (CSCST) fellowships have traditionally been undertaken as a means to access subspecialty clinical training which is otherwise unavailable in higher training programs. However, fellowships have a role beyond this subspecialization model, particularly in meeting the non-clinical training needs of new CSCST graduates.The design and goals of fellowship posts should be considered in this context, to align them with the reported needs of new consultants. Special consideration should be given to defining roles of independence for the fellow and to the nature of the mentorship relationship, distinguishing these posts from higher specialist training. Well-designed post-CSCST fellowships have an important role in facilitating the successful transition to consultanthood.

Recapitulation of pathophysiological features of AD in SARS-CoV-2-infected subjects.

Infection with the etiological agent of COVID-19, SARS-CoV-2, appears capable of impacting cognition in some patients with post-acute sequelae of SARS-CoV-2 (PASC). To evaluate neuropathophysiological consequences of SARS-CoV-2 infection, we examine transcriptional and cellular signatures in the Brodmann area 9 (BA9) of the frontal cortex and the hippocampal formation (HF) in SARS-CoV-2, Alzheimer's disease (AD), and SARS-CoV-2-infected AD individuals compared to age- and gender-matched neurological cases. Here, we show similar alterations of neuroinflammation and blood-brain barrier integrity in SARS-CoV-2, AD, and SARS-CoV-2-infected AD individuals. Distribution of microglial changes reflected by the increase in Iba-1 reveals nodular morphological alterations in SARS-CoV-2-infected AD individuals. Similarly, HIF-1α is significantly upregulated in the context of SARS-CoV-2 infection in the same brain regions regardless of AD status. The finding may help in informing decision-making regarding therapeutic treatments in patients with neuro-PASC, especially those at increased risk of developing AD.

Exposure to World Trade Center Dust Exacerbates Cognitive Impairment and Evokes a Central and Peripheral Pro-Inflammatory Transcriptional Profile in an Animal Model of Alzheimer's Disease.

BACKGROUND: The terrorist attacks on September 11, 2001, on the World Trade Center (WTC) led to intense fires and a massive dense cloud of toxic gases and suspended pulverized debris. In the subsequent years, following the attack and cleanup efforts, a cluster of chronic health conditions emerged among First Responders (FR) who were at Ground Zero for prolonged periods and were repeatedly exposed to high levels of WTC particulate matter (WTCPM). Among those are neurological complications which may increase the risk for the development of Alzheimer's disease (AD) later in life. OBJECTIVE: We hypothesize that WTCPM dust exposure affects the immune cross-talking between the periphery and central nervous systems that may induce brain permeability ultimately promoting AD-type phenotype. METHODS: 5XFAD and wild-type mice were intranasally administered with WTCPM dust collected at Ground Zero within 72 h after the attacks. Y-maze assay and novel object recognition behavioral tests were performed for working memory deficits and learning and recognition memory, respectively. Transcriptomic analysis in the blood and hippocampus was performed and confirmed by RT qPCR. RESULTS: Mice exposed to WTCPM dust exhibited a significant impairment in spatial and recognition short and long-term memory. Furthermore, the transcriptomic analysis in the hippocampal formation and blood revealed significant changes in genes related to immune-inflammatory responses, and blood-brain barrier disruption. CONCLUSION: These studies suggest a putative peripheral-brain immune inflammatory cross-talking that may potentiate cognitive decline, identifying for the first time key steps which may be therapeutically targetable in future studies in WTC FR.

A survey of perceived traumatic birth experiences in an Irish maternity sample - prevalence, risk factors and follow up.

OBJECTIVES: To establish the prevalence and correlates of a subjectively traumatic birth experience in an Irish maternity sample. DESIGN: A questionnaire routinely provided to all women prior to hospital discharge post-birth was amended for data collection for this study. Two additional questions seeking information about women's perceptions of their birth were added and analysed. Women who described their birth as traumatic and agreed to follow-up, received a City Birth Trauma Scale (Ayers et al., 2018) at subsequent follow-up (6 to 12 weeks postpartum). Demographic, obstetric, neonatal variables and factors associated with birth trauma were collected from electronic maternity records retrospectively. SETTING: A postnatal ward in an Irish maternity hospital which provides postnatal care for public maternity patients. PARTICIPANTS: Postpartum women (N=1154) between 1 and 5 days postpartum. MEASUREMENTS & FINDINGS: Participants completed the Edinburgh Postnatal Depression Scale (EPDS) (Cox et al., 1987) with two additional questions about birth trauma. Eighteen percent (n=209) of women reported their birth as traumatic. Factors associated with reporting birth as traumatic included a history of depression, raised EPDS scores (>12), induction of labour, combined ventouse/forceps birth, and postpartum haemorrhage. Of these 209 women, 134 went on to complete the City Birth Trauma Scale (Ayers et al., 2018). The average score was 3.84 and 6 of this sample (4%) reached the threshold for postpartum post-traumatic stress disorder (PTSD). KEY CONCLUSIONS: This study identified a prevalence of 18% of women experiencing birth as traumatic and the potentially important role of a current and past history of depression, postpartum haemorrhage, induction of labour and operative vaginal birth in defining a traumatic birth experience. The majority of women were resilient to birth trauma, few developed PTSD , but a larger cohort had significant functional impairment associated with sub-clinical postpartum PTSD symptoms. IMPLICATIONS FOR PRACTICE: Maternity care providers should be aware of the risk factors for traumatic birth. Introducing a trauma-informed approach amongst midwives and maternity care providers in the postnatal period may help to detect emerging or established persisting trauma-related symptoms. For women with sub-clinical postpartum PTSD symptoms a detailed enquiry may be more effective in identifying postpartum PTSD at a later postnatal stage e.g., at six weeks postpartum. Maternity services should provide ongoing supports for women who have experienced birth trauma.

Molecular and cellular similarities in the brain of SARS-CoV-2 and Alzheimer's disease individuals.

Infection with the etiological agent of COVID-19, SARS-CoV-2, appears capable of impacting cognition, which some patients with Post-acute Sequelae of SARS-CoV-2 (PASC). To evaluate neuro-pathophysiological consequences of SARS-CoV-2 infection, we examine transcriptional and cellular signatures in the Broadman area 9 (BA9) of the frontal cortex and the hippocampal formation (HF) in SARS-CoV-2, Alzheimer's disease (AD) and SARS-CoV-2 infected AD individuals, compared to age- and gender-matched neurological cases. Here we show similar alterations of neuroinflammation and blood-brain barrier integrity in SARS-CoV-2, AD, and SARS-CoV-2 infected AD individuals. Distribution of microglial changes reflected by the increase of Iba-1 reveal nodular morphological alterations in SARS-CoV-2 infected AD individuals. Similarly, HIF-1α is significantly upregulated in the context of SARS-CoV-2 infection in the same brain regions regardless of AD status. The finding may help to inform decision-making regarding therapeutic treatments in patients with neuro-PASC, especially those at increased risk of developing AD. Teaser: SARS-CoV-2 and Alzheimer's disease share similar neuroinflammatory processes, which may help explain neuro-PASC.

The Carbamate, Physostigmine does not Impair Axonal Transport in Rat Cortical Neurons.

Among the various chemicals that are commonly used as pesticides, organophosphates (OPs), and to a lesser extent, carbamates, are most frequently associated with adverse long-term neurological consequences. OPs and the carbamate, pyridostigmine, used as a prophylactic drug against potential nerve agent attacks, have also been implicated in Gulf War Illness (GWI), which is often characterized by chronic neurological symptoms. While most OP- and carbamate-based pesticides, and pyridostigmine are relatively potent acetylcholinesterase inhibitors (AChEIs), this toxicological mechanism is inadequate to explain their long-term health effects, especially when no signs of acute cholinergic toxicity are exhibited. Our previous work suggests that a potential mechanism of the long-term neurological deficits associated with OPs is impairment of axonal transport (AXT); however, we had not previously evaluated carbamates for this effect. Here we thus evaluated the carbamate, physostigmine (PHY), a highly potent AChEI, on AXT using an in vitro neuronal live imaging assay that we have previously found to be very sensitive to OP-related deficits in AXT. We first evaluated the OP, diisopropylfluorophosphate (DFP) (concentration range 0.001-10.0 µM) as a reference compound that we found previously to impair AXT and subsequently evaluated PHY (concentration range 0.01-100 nM). As expected, DFP impaired AXT in a concentration-dependent manner, replicating our previously published results. In contrast, none of the concentrations of PHY (including concentrations well above the threshold for impairing AChE) impaired AXT. These data suggest that the long-term neurological deficits associated with some carbamates are not likely due to acute impairments of AXT.

Research by Psychiatric Trainees and Early Career Psychiatrists-Results of a Survey From 34 Countries in Europe.

Clinical psychiatric practice should be intricately linked with research work. Although psychiatric trainees and early career psychiatrists (ECPs) are in the frontline of clinical services, little is known about how much access they have to research opportunities. A semi-structured questionnaire of 35 questions-exploring research goals achieved, facilitators and barriers as well as personal context-was sent to psychiatric trainees and ECPs across Europe. The survey was disseminated through the local committees of the main professional psychiatric societies in Europe. A total of 258 individuals working in 34 European countries participated. The majority (69.8%) were psychiatric trainees within training in adult psychiatry. Most participants (69.0%) were highly interested in research, but faced major obstacles toward their research activities, such as lack of time and funding. They were highly satisfied with mentoring and publishing papers. Only half of the participants, however, had already published a scientific article, and only a few have been able to contribute to randomized clinical trials (20.9%). A large proportion of participants (87.2%) reported to conduct research after or during a mixture of working hours and after working hours. Only one tenth ever received a grant for their work. These findings highlight that the key barriers for the performance of research are lack of time and funding. Psychiatric trainees and ECPs are motivated to perform research but need support and regular opportunities.

SARS-CoV-2 Antibody Testing in Health Care Workers: A Comparison of the Clinical Performance of Three Commercially Available Antibody Assays.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies are an excellent indicator of past COVID-19 infection. As the COVID-19 pandemic progresses, retained sensitivity over time is an important quality in an antibody assay that is to be used for the purpose of population seroprevalence studies. We compared 5,788 health care worker (HCW) serum samples by using two serological assays (Abbott SARS-CoV-2 anti-nucleocapsid immunoglobulin G (IgG) and Roche anti-SARS-CoV-2 anti-nucleocapsid total antibody) and a subset of samples (all Abbott assay positive or grayzone, n = 485) on Wantai SARS-CoV-2 anti-spike antibody enzyme-linked immunosorbent assay (ELISA). For 367 samples from HCW with a previous PCR-confirmed SARS-CoV-2 infection, we correlated the timing of infection with assay results. Overall, seroprevalence was 4.2% on Abbott and 9.5% on Roche. Of those with previously confirmed infection, 41% (150/367) and 95% (348/367) tested positive on Abbott and Roche, respectively. At 21 weeks (150 days) after confirmed infection, positivity on Abbott started to decline. Roche positivity was retained for the entire study period (33 weeks). Factors associated (P ≤ 0.050) with Abbott seronegativity in those with previous PCR-confirmed infection included sex (odds ratio [OR], 0.30 male ; 95% confidence interval [CI], 0.15 to 0.60), symptom severity (OR 0.19 severe symptoms; 95% CI, 0.05 to 0.61), ethnicity (OR, 0.28 Asian ethnicity; 95% CI, 0.12 to 0.60), and time since PCR diagnosis (OR, 2.06 for infection 6 months previously; 95% CI, 1.01 to 4.30). Wantai detected all previously confirmed infections. In our population, Roche detected antibodies up to at least 7 months after natural infection with SARS-CoV-2. This finding indicates that the Roche total antibody assay is better suited than Abbott IgG assay to population-based studies. Wantai demonstrated high sensitivity, but sample selection was biased. The relationship between serological response and functional immunity to SARS-CoV-2 infection needs to be delineated. IMPORTANCE As the COVID-19 pandemic progresses, retained sensitivity over time is an important quality in an antibody assay that is to be used for the purpose of population seroprevalence studies. There is a relative paucity of published literature in this field to help guide public health specialists when planning seroprevalence studies. In this study, we compared results of 5,788 health care worker blood samples tested by using two assays (Roche and Elecsys, anti-nucleocapsid antibody) and by testing a subset on a third assay (Wantai enzyme-linked immunosorbent assay [ELISA] anti-spike antibody). We found significant differences in the performance of these assays, especially with distance in time from PCR-confirmed COVID-19 infection, and we feel these results may significantly impact the choice of assay for others conducting similar studies.

The Viral Hypothesis in Alzheimer's Disease: Novel Insights and Pathogen-Based Biomarkers.

Early diagnosis of Alzheimer's disease (AD) and the identification of significant risk factors are necessary to better understand disease progression, and to develop intervention-based therapies prior to significant neurodegeneration. There is thus a critical need to establish biomarkers which can predict the risk of developing AD before the onset of cognitive decline. A number of studies have indicated that exposure to various microbial pathogens can accelerate AD pathology. Additionally, several studies have indicated that amyloid-ß possess antimicrobial properties and may act in response to infection as a part of the innate immune system. These findings have led some to speculate that certain types of infections may play a significant role in AD pathogenesis. In this review, we will provide an overview of studies which suggest pathogen involvement in AD. Additionally, we will discuss a number of pathogen-associated biomarkers which may be effective in establishing AD risk. Infections that increase the risk of AD represent a modifiable risk factor which can be treated with therapeutic intervention. Pathogen-based biomarkers may thus be a valuable tool for evaluating and decreasing AD risk across the population.

Potential Novel Role of COVID-19 in Alzheimer's Disease and Preventative Mitigation Strategies.

There are a number of potential implications for the field of Alzheimer's disease (AD) stemming from the global spread of SARS-CoV-2. Neuroinflammation is known to be a prominent feature of neurodegeneration and plays a major role in AD pathology. Immune response and excessive inflammation in COVID-19 may also accelerate the progression of brain inflammatory neurodegeneration, and elderly individuals are more susceptible to severe outcomes after SARS-CoV-2 infection. Individuals with type 2 diabetes (T2D) are at an increased risk for AD as well as severe outcomes after SARS-CoV-2 infection. Genetic and socioeconomic factors influencing the rates of T2D, AD, and COVID-19 severity may create an exceptionally high-risk profile for certain demographics such as African Americans and Hispanic Americans. Type I interferon response plays an important role in both host response to viral infection, as well as AD pathology and may be a sensible therapeutic target in both AD and COVID-19.

The Innate Immune System and Inflammatory Priming: Potential Mechanistic Factors in Mood Disorders and Gulf War Illness.

Gulf War Illness is a chronic multisystem disorder affecting approximately a third of the Veterans of the Gulf War, manifesting with physical and mental health symptoms such as cognitive impairment, neurological abnormalities, and dysregulation of mood. Among the leading theories into the etiology of this multisystem disorder is environmental exposure to the various neurotoxins encountered in the Gulf Theatre, including organophosphates, nerve agents, pyridostigmine bromide, smoke from oil well fires, and depleted uranium. The relationship of toxin exposure and the pathogenesis of Gulf War Illness converges on the innate immune system: a nonspecific form of immunity ubiquitous in nature that acts to respond to both exogenous and endogenous insults. Activation of the innate immune system results in inflammation mediated by the release of cytokines. Cytokine mediated neuroinflammation has been demonstrated in a number of psychiatric conditions and may help explain the larger than expected population of Gulf War Veterans afflicted with a mood disorder. Several of the environmental toxins encountered by soldiers during the first Gulf War have been shown to cause upregulation of inflammatory mediators after chronic exposure, even at low levels. This act of inflammatory priming, by which repeated exposure to chronic subthreshold insults elicits robust responses, even after an extended period of latency, is integral in the connection of Gulf War Illness and comorbid mood disorders. Further developing the understanding of the relationship between environmental toxin exposure, innate immune activation, and pathogenesis of disease in the Gulf War Veterans population, may yield novel therapeutic targets, and a greater understanding of disease pathology and subsequently prevention.