Markers of blood-brain barrier disruption increase early and persistently in COVID-19 patients with neurological manifestations

Involvement of oxidative stress in post-acute sequelae of COVID-19: clinical implications

Oxidative stress (OS) plays a key role in the pathophysiology of COVID-19 and may be associated with sequelae after severe SARS-CoV-2 infection. This study evaluated OS and inflammation biomarkers in blood from individuals with post-acute sequelae of COVID-19 (PASC). 64 male and female participants were distributed into three groups: healthy individuals (n = 20), acute COVID-19 patients (symptoms for <3 weeks, n = 15), and PASC patients (symptoms for >12 weeks, n = 29). Analyses included inflammatory cytokines, myeloperoxidase (MPO) activity, and OS markers, such as superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), gamma-glutamyl transferase (GGT), reduced glutathione (GSH), uric acid (UA), thiobarbituric acid reactive substances (TBARS), and protein carbonyls (PC). Individuals with PASC showed increased IL-6 and IL-8. Both COVID-19 groups exhibited decreased SOD and CAT. GST decreased only in the acute group. Elevated GGT and GSH were found in the PASC group. High UA levels were observed in PASC individuals. There were no changes in TBARS values ⁣⁣in the PASC group. However, PC concentrations were elevated only in this group. Correlations were identified between inflammatory markers and OS parameters. These findings suggest that individuals with PASC pronounced OS, which potentially exacerbates disease complications. Monitoring OS biomarkers could aid in patient prognosis and management.

Exploring human brain development and disease using assembloids

How the human brain develops and what goes awry in neurological disorders represent two long-lasting questions in neuroscience. Owing to the limited access to primary human brain tissue, insights into these questions have been largely gained through animal models. However, there are fundamental differences between developing mouse and human brain, and neural organoids derived from human pluripotent stem cells (hPSCs) have recently emerged as a robust experimental system that mimics self-organizing and multicellular features of early human brain development. Controlled integration of multiple organoids into assembloids has begun to unravel principles of cell-cell interactions. Moreover, patient-derived or genetically engineered hPSCs provide opportunities to investigate phenotypic correlates of neurodevelopmental disorders and to develop therapeutic hypotheses. Here, we outline the advances in technologies that facilitate studies by using assembloids and summarize their applications in brain development and disease modeling. Lastly, we discuss the major roadblocks of the current system and potential solutions.

Impact of mesenchymal stromal/stem cell infusions on circulating inflammatory biomarkers in COVID-19 patients: analysis of a phase I-IIa trial

BACKGROUND AIMS

SARS-CoV-2 infection triggers respiratory inflammation with potentially fatal systemic effects. Mesenchymal stromal/stem cells (MSCs) are promising for treating severe COVID-19 due to their anti-inflammatory and regenerative capacities. This study investigates the effects of allogeneic MSCs in severe COVID-19 pneumonia.

METHODS

In the phase I/IIa RESCAT trial (May 2021-Feb 2022), patients with severe COVID-19 pneumonia received two intravenous MSC infusions and were compared to a control group (CTRL). To assess cytokine and biomarker responses, the MSC group was matched 1:2 with standard care patients (mCTRL) by age, gender, BMI, and PaO2/FiO2 (Nov 2020-Feb 2021). Random-effects linear regression evaluated cytokine and biomarker trends over time between MSC and control groups.

RESULTS

Seventeen patients (MSC = 5, CTRL = 2, mCTRL = 10) were analyzed. Two MSC infusions were feasible and safe, with all patients discharged on average 15 ± 3.7 days postsecond infusion. While IL1RA and IL18 levels significantly increased in CTRL-mCTRL patients (P = 0.044 and P = 0.032), MSC treatment averted these rises, showing a distinct trajectory, particularly for IL1RA. MSC treatment also reduced IL6 levels compared to CTRL-mCTRL, while both groups showed similar reductions in Long pentraxin. Furthermore, MSC infusions prevented the neurofilament light chain surge observed in CTRL patients.

CONCLUSIONS

MSC in COVID-19 patients resulted safe and feasible, effectively modulating inflammatory cytokines, in particular mitigating brain damage related biomarker, suggesting both reduced inflammation and a potential neurological protection.

No substantial neurocognitive impact of COVID-19 across ages and disease severity: a multicenter biomarker study of SARS-CoV-2 positive and negative adult and pediatric patients with acute respiratory tract infections

BACKGROUND

Compared to intensive care unit patients with SARS-CoV-2 negative acute respiratory tract infections, patients with SARS-CoV-2 are supposed to develop more frequently and more severely neurologic sequelae. Delirium and subsequent neurocognitive deficits (NCD) have implications for patients' morbidity and mortality. However, the extent of brain injury during acute COVID-19 and subsequent NCD still remain largely unexplored. Body-fluid biomarkers may offer valuable insights into the quantification of acute delirium, brain injury and may help to predict subsequent NCD following COVID-19.

METHODS

In a multicenter, observational case-control study, conducted across four German University Hospitals, hospitalized adult and pediatric patients with an acute COVID-19 and SARS-CoV-2 negative controls presenting with acute respiratory tract infections were included. Study procedures comprised the assessment of pre-existing neurocognitive function, daily screening for delirium, neurological examination and blood sampling. Fourteen biomarkers indicative of neuroaxonal, glial, neurovascular injury and inflammation were analyzed. Neurocognitive functions were re-evaluated after three months.

RESULTS

We enrolled 118 participants (90 adults, 28 children). The incidence of delirium [85 out of 90 patients (94.4%) were assessable for delirium) was comparable between patients with COVID-19 [16 out of 61 patients (26.2%)] and SARS-CoV-2 negative controls [8 out of 24 patients (33.3%); p > 0.05] across adults and children. No differences in outcomes as measured by the modified Rankin Scale, the Short-Blessed Test, the Informant Questionnaire on Cognitive Decline in the Elderly, and the pediatrics cerebral performance category scale were observed after three months. Levels of body-fluid biomarkers were generally elevated in both adult and pediatric cohorts, without significant differences between SARS-CoV-2 negative controls and COVID-19. In COVID-19 patients experiencing delirium, levels of GFAP and MMP-9 were significantly higher compared to those without delirium.

CONCLUSIONS

Delirium and subsequent NCD are not more frequent in COVID-19 as compared to SARS-CoV-2 negative patients with acute respiratory tract infections. Consistently, biomarker levels of brain injury indicated no differences between COVID-19 cases and SARS-CoV-2 negative controls. Our data suggest that delirium in COVID-19 does not distinctly trigger substantial and persistent subsequent NCD compared to patients with other acute respiratory tract infections.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04359914; date of registration 24-APR 2020.

Biomarkers of blood-brain barrier and neurovascular unit integrity in human cognitive impairment and dementia

Blood-brain barrier (BBB) dysfunction is recognized as an early step in the development of Alzheimer's disease and related dementias (ADRD). Biomarkers are needed to monitor BBB integrity over time, better understand the role of the BBB in neurodegeneration, potentially help define long-term ADRD risk, and monitor effects of therapeutics. In this review, we discuss the current biomarkers used to detect human BBB dysfunction in the context of cognitive decline and dementia. We also discuss promising candidate fluid biomarkers to detect BBB dysfunction in blood. HIGHLIGHTS: BBB permeability occurs during normal aging and is further exacerbated in ADRD. In this review, we discuss in vivo imaging and CSF biomarkers of BBB dysfunction currently used in the setting of aging and ADRD in humans. We also review promising candidate blood-based biomarkers that may represent BBB dysfunction.

Blood neurofilament light chain and S100B as biomarkers of neurological involvement and functional prognosis in COVID-19: a multicenter study

BACKGROUND AND AIM

COVID-19 is associated with neurological complications, termed neuro-COVID, affecting patient outcomes. We aimed to evaluate the association between serum neurofilament light chain (NfL) and S100B biomarkers with the presence of neurological manifestations and functional prognosis in COVID-19 patients.

METHODS

A multicenter prospective cohort study was conducted in three hospitals in the Emilia-Romagna region, Italy, from March 2020 to April 2022. Hospitalized patients with PCR-confirmed COVID-19 were enrolled. Serum S100B and NfL levels were measured in the acute or subacute phase after admission. Diagnostic accuracy was assessed using receiver operating characteristic (ROC) analyses. Statistical analyses were performed to evaluate the association between biomarkers, clinical/laboratory variables, and prognosis, specifically focusing on worsening of the modified Rankin Scale (mRS) from admission to discharge.

RESULTS

A total of 279 patients (153 males, median age 76.7 years) were included. Among them, 69 (24.7%) developed neuro-COVID. Serum NfL levels were significantly higher in the neuro-COVID group (median 110 vs 68.3; p = 0.035) and correlated with severe encephalopathy and extracranial neurologic manifestations. The ROC analysis showed low accuracy in the discrimination between the two groups for both NfL and S100B. Key predictors of worsening mRS included mechanical ventilation (OR = 9.56, 95% CI = 1.67-54.75; p = 0.011), severe encephalopathy (OR = 5.10, 95% CI = 1.58-16.19; p = 0.006), and elevated S100B levels (OR = 2.62, 95% CI = 1.10-6.46; p = 0.037).

CONCLUSIONS

Serum NfL and S100B biomarkers were not accurate in discriminating neuro-COVID patients, however NfL levels were associated with severe and extracranial neuro-COVID, while S100B with functional outcomes, potentially informing clinical management.

The Secretome of Brain Endothelial Cells Exposed to the Pyrrolizidine Alkaloid Monocrotaline Induces Astrocyte Reactivity and Is Neurotoxic

Monocrotaline (MCT) has well-characterized hepatotoxic and pneumotoxic effects attributed to its active pyrrole metabolites. Studies have previously shown that astrocytes and neurons are targets of MCT, and that toxicity is attributed to astrocyte P450 metabolism to reactive metabolites. However, little is known about MCT toxicity and metabolism by brain endothelial cells (BECs), cells that, together with astrocytes, are specialized in xenobiotic metabolism and neuroprotection. Therefore, in the present study, we evaluated the toxicity of MCT in BECs, and the effects on astrocyte reactivity and neuronal viability in vitro. MCT was purified from Crotalaria retusa seeds. BECs, obtained from the brain of adult Wistar rats, were treated with MCT (1-500 µM), and cell viability and morphology were analyzed after 24-72 h of treatment. Astrocyte/neuron co-cultures were prepared from the cortex of neonatal and embryonic Wistar rats, and the cultures were exposed to conditioned medium (secretome) derived from BECs previously treated with MCT (100-500 µM, SBECM100/500). MCT was not toxic to BECs at the concentrations used and induced a concentration-dependent increase in cell dehydrogenase after 72 h of treatment, suggesting resistance to damage and drug metabolism. However, exposure of astrocyte/neuron co-cultures to the SBECM for 24 h induced changes in the cell morphology, vacuolization, and overexpression of GFAP in astrocytes, characterizing astrogliosis, and neurotoxicity with a reduction in the length of neurites labeled for β-III-tubulin, effects that were MCT concentration-dependent. These results support the hypothesis that MCT neurotoxicity may be due to products of its metabolism by components of the BBB such as BECs and astrocytes, which may be responsible for the brain lesions and symptoms observed after intoxication.

Cerebromicrovascular mechanisms contributing to long COVID: implications for neurocognitive health

Long COVID (also known as post-acute sequelae of SARS-CoV-2 infection [PASC] or post-COVID syndrome) is characterized by persistent symptoms that extend beyond the acute phase of SARS-CoV-2 infection, affecting approximately 10% to over 30% of those infected. It presents a significant clinical challenge, notably due to pronounced neurocognitive symptoms such as brain fog. The mechanisms underlying these effects are multifactorial, with mounting evidence pointing to a central role of cerebromicrovascular dysfunction. This review investigates key pathophysiological mechanisms contributing to cerebrovascular dysfunction in long COVID and their impacts on brain health. We discuss how endothelial tropism of SARS-CoV-2 and direct vascular infection trigger endothelial dysfunction, impaired neurovascular coupling, and blood-brain barrier disruption, resulting in compromised cerebral perfusion. Furthermore, the infection appears to induce mitochondrial dysfunction, enhancing oxidative stress and inflammation within cerebral endothelial cells. Autoantibody formation following infection also potentially exacerbates neurovascular injury, contributing to chronic vascular inflammation and ongoing blood-brain barrier compromise. These factors collectively contribute to the emergence of white matter hyperintensities, promote amyloid pathology, and may accelerate neurodegenerative processes, including Alzheimer's disease. This review also emphasizes the critical role of advanced imaging techniques in assessing cerebromicrovascular health and the need for targeted interventions to address these cerebrovascular complications. A deeper understanding of the cerebrovascular mechanisms of long COVID is essential to advance targeted treatments and mitigate its long-term neurocognitive consequences.

The relationship among H2S, neuroinflammation and MMP-9 in BBB injury following ischemic stroke

Blood-brain barrier (BBB) is located at the interface between the central nervous system (CNS) and the circulatory system, which maintains the microenvironmental homeostasis of the CNS. BBB damage is a result of CNS diseases, including ischemic stroke, and is a cause of CNS deterioration. Cerebral ischemia unleashes a profound inflammatory response to remove the damaged tissue in the CNS and prepare the brain for repair. However, the excessive neuroinflammation following stroke onset is associated with BBB breakdown, resulting in neuronal injury and worse neurological outcomes. Additionally, matrix metalloproteinases (MMPs) are likewise responsible for the BBB injury and participate in the pathological processes of neuroinflammation following ischemic stroke. Hydrogen sulfide (H2S) is one of gaseous signaling and freely diffusing molecules. Low concentration of H2S yields the neuroprotection against BBB damage following stroke. This review discussed the current knowledge about the detrimental roles of neuroinflammation and MMPs in BBB injury following ischemic stroke. Specifically, we provided an updated overview of H2S in protecting against BBB injury following ischemic stroke via anti-neuroinflammation and inhibiting MMP-9.

Nobiletin and Eriodictyol Suppress Release of IL-1β, CXCL8, IL-6, and MMP-9 from LPS, SARS-CoV-2 Spike Protein, and Ochratoxin A-Stimulated Human Microglia

Neuroinflammation is involved in various neurological and neurodegenerative disorders in which the activation of microglia is one of the key factors. In this study, we examined the anti-inflammatory effects of the flavonoids nobiletin (5,6,7,8,3',4'-hexamethoxyflavone) and eriodictyol (3',4',5,7-tetraxydroxyflavanone) on human microglia cell line activation stimulated by either lipopolysaccharide (LPS), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) full-length Spike protein (FL-Spike), or the mycotoxin ochratoxin A (OTA). Human microglia were preincubated with the flavonoids (10, 50, and 100 µM) for 2 h, following which, they were stimulated for 24 h. The inflammatory mediators interleukin-1 beta (IL-1β), chemokine (C-X-C motif) ligand 8 (CXCL8), IL-6, and matrix metalloproteinase-9 (MMP-9) were quantified in the cell culture supernatant by enzyme-linked immunosorbent assay (ELISA). Both nobiletin and eriodictyol significantly inhibited the LPS, FL-Spike, and OTA-stimulated release of IL-1β, CXCL8, IL-6, and MMP-9 at 50 and 100 µM, while, in most cases, nobiletin was also effective at 10 µM, with the most pronounced reductions at 100 µM. These findings suggest that both nobiletin and eriodictyol are potent inhibitors of the pathogen-stimulated microglial release of inflammatory mediators, highlighting their potential for therapeutic application in neuroinflammatory diseases, such as long COVID.

Long COVID-19 outcomes of patients with pre-existing dementia

BACKGROUND

Although COVID-19 has been linked to worse acute outcomes in patients with some neurodegenerative disorders, its long-term impact on dementia remains unclear.

OBJECTIVE

To investigate the outcomes of COVID-19 survivors with dementia.

METHODS

This retrospective study evaluated 9806 patients with dementia in the Montefiore Health System (January 2016 to July 2023). Comparisons were made between dementia patients with and without a positive SARS-CoV-2 polymerase-chain-reaction test who had a follow-up at least two weeks post-infection. Outcomes included all-cause mortality, major adverse cardiovascular events (MACE), new-onset dysphagia, dyspnea, fatigue, new-onset sleep disturbances, altered mental status, first-time fall, headache, new-onset depression, and new-onset anxiety. Adjusted hazard ratios (aHR) were computed adjusting for age, sex, race, ethnicity, and pre-existing comorbidities.

RESULTS

Dementia patients with COVID-19 were younger, more likely to be male, and had a higher prevalence of major pre-existing comorbidities compared to those without COVID-19. Patients who survived acute COVID-19 were more likely to die than non-COVID controls after adjusting for covariates (aHR = 1.65 [1.43, 1.91]). COVID-19 was significantly associated with higher risk of MACE (aHR = 1.58 [1.41, 1.78]), new-onset dysphagia (aHR = 1.64 [1.42, 1.91]), dyspnea (aHR = 1.27 [1.12, 1.44]), fatigue (aHR = 1.42 [1.22, 1.65]), new-onset sleep disturbances (aHR = 1.36 [1.15, 1.60]), altered mental status (aHR = 1.36 [1.16, 1.59]), and first-time fall (aHR = 1.34 [1.09, 1.65]).

CONCLUSIONS

COVID-19 increases the risk of mortality and other adverse health outcomes in dementia patients. These findings highlight the need for closer follow-up and management strategies for dementia patients post-COVID-19.

Antibodies against SARS-CoV-2 spike protein in the cerebrospinal fluid of COVID-19 patients and vaccinated controls: a multicentre study

INTRODUCTION

SARS-CoV-2 antibodies in the cerebrospinal fluid (CSF) of COVID-19 patients possibly reflect blood-cerebrospinal fluid barrier (BCB) disruption due to systemic inflammation. However, some studies indicate that CSF antibodies signal a neurotropic infection. Currently, larger studies are needed to clarify this, and it is unknown if CSF antibodies appear solely after infection or also after COVID-19 vaccination. Therefore, we aimed to investigate the CSF dynamics of SARS-CoV-2 antibodies in a multicenter study of COVID-19 patients and vaccinated controls.

METHODS

A cohort study of Danish and Norwegian COVID-19 patients and controls investigated with a lumbar puncture (April 2020-December 2022). Serum and CSF were analysed locally for routine investigations, and centrally at Statens Serum Institut (Danish governmental public health institute) for SARS-CoV-2 IgG antibodies against the spike protein using the Euroimmun (quantitative) and Wantai (qualitative) assays. Primary outcome was the quantity of CSF SARS-CoV-2 antibodies post-COVID versus post-vaccination. Secondary outcomes included regression models examining the relationship between CSF antibodies and serum levels, albumin ratio, CSF pleocytosis, COVID-19 severity, and temporal antibody dynamics.

RESULTS

We included 124 individuals (Mean [SD] age 47.2 [16.6]; 59.7% males surviving COVID-19 and controls. Of these, 86 had paired CSF-serum testing. Antibody-index calculations did not support a SARS-CoV-2 brain infection. Multi-variate regression revealed that CSF SARS-CoV-2 antibodies were most strongly influenced by serum antibody levels and BCB permeability, as measured by increasing albumin ratio. CSF antibody levels displayed a dose-response relationship (p < 0.0001) influenced by preceding vaccinations or infections. CSF antibody levels (median [IQR]) were highest among those both previously infected and vaccinated, 100.0 [25.0-174.0], and those vaccinated without prior infection, 85.0 [12.0-142.0], and lowest among previously infected individuals without preceding vaccination, 5.9 [2.7-55.1], (p = 0.003). SARS-CoV-2 antibodies in CSF were also detected via qualitative assays in the COVID-19 (46.8%) and vaccinated (78.6%) groups, p = 0.03.

CONCLUSION

SARS-CoV-2 antibodies detected in CSF can be derived following both infection and vaccination for COVID-19. CSF antibody levels increase in a dose-response relationship with the number of prior infections and vaccinations and are most strongly influenced by serum antibody levels and BCB permeability. These findings stress the importance of carefully interpreting CSF antibody results when assessing neurological complications following infections not categorized as neurotropic.

Persistence of spike protein at the skull-meninges-brain axis may contribute to the neurological sequelae of COVID-19

SARS-CoV-2 infection is associated with long-lasting neurological symptoms, although the underlying mechanisms remain unclear. Using optical clearing and imaging, we observed the accumulation of SARS-CoV-2 spike protein in the skull-meninges-brain axis of human COVID-19 patients, persisting long after viral clearance. Further, biomarkers of neurodegeneration were elevated in the cerebrospinal fluid from long COVID patients, and proteomic analysis of human skull, meninges, and brain samples revealed dysregulated inflammatory pathways and neurodegeneration-associated changes. Similar distribution patterns of the spike protein were observed in SARS-CoV-2-infected mice. Injection of spike protein alone was sufficient to induce neuroinflammation, proteome changes in the skull-meninges-brain axis, anxiety-like behavior, and exacerbated outcomes in mouse models of stroke and traumatic brain injury. Vaccination reduced but did not eliminate spike protein accumulation after infection in mice. Our findings suggest persistent spike protein at the brain borders may contribute to lasting neurological sequelae of COVID-19.

Long COVID and pituitary dysfunctions: a bidirectional relationship?

Long COVID is a novel emerging syndrome known to affect multiple health areas in patients previously infected by SARS-CoV-2 markedly impairing their quality of life. The pathophysiology of Long COVID is still largely poorly understood and multiple mechanisms were proposed to underlie its occurrence, including alterations in the hormonal hypothalamic-pituitary axes. Aim of this review is to present and discuss the potential negative implications of these hormonal dysfunctions in promoting and influencing the Long COVID syndrome. To date, the hypothalamic-pituitary-adrenal axis is the mostly investigated and several studies have reported a prolonged impairment leading to mild and subclinical forms of central adrenal insufficiency. Few data are also available regarding central hypogonadism, central hypothyroidism and growth hormone (GH) deficiency. A high prevalence of central hypogonadism in COVID-19 survivors several months after recovery was consistently reported in different cohorts. Conversely, very few data are available on the hypothalamic-pituitary-thyroid axis function that was mainly shown to be preserved in COVID-19 survivors. Finally, a potential impairment of the hypothalamic-GH axis in Long COVID has also been reported. These data altogether may suggest a novel possible pituitary-centred pathophysiological view of Long COVID syndrome which if confirmed by large clinical studies may have relevant implication for the diagnostic and therapeutic approach at least in a subset of patients with the syndrome.

COVID-19: a multi-organ perspective

In this mini review, we explore the complex network of inflammatory reactions incited by SARS-CoV-2 infection, which extends its reach well beyond the respiratory domain to influence various organ systems. Synthesizing existing literature, it elucidates how the hyperinflammation observed in COVID-19 patients affects multiple organ systems leading to physiological impairments that can persist over long after the resolution of infection. By exploring the systemic manifestations of this inflammatory cascade, from acute respiratory distress syndrome (ARDS) to renal impairment and neurological sequelae, the review highlights the profound interplay between inflammation and organ dysfunction. By synthesizing recent research and clinical observations, this mini review aims to provide an overview of the systemic interactions and complications associated with COVID-19, underscoring the need for an integrated approach to treatment and management. Understanding these systemic effects is crucial for improving patient outcomes and preparing for future public health challenges.

Anti-Inflammatory and Neuroprotective Polyphenols Derived from the European Olive Tree, Olea europaea L., in Long COVID and Other Conditions Involving Cognitive Impairment

The European olive tree, Olea europaea L., and its polyphenols hold great therapeutic potential to treat neuroinflammation and cognitive impairment. This review examines the evidence for the anti-inflammatory and neuroprotective actions of olive polyphenols and their potential in the treatment of long COVID and neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS). Key findings suggest that olive polyphenols exhibit antioxidant, anti-inflammatory, neuroprotective, and antiviral properties, making them promising candidates for therapeutic intervention, especially when formulated in unique combinations. Recommendations for future research directions include elucidating molecular pathways through mechanistic studies, exploring the therapeutic implications of olive polyphenol supplementation, and conducting clinical trials to assess efficacy and safety. Investigating potential synergistic effects with other agents addressing different targets is suggested for further exploration. The evidence reviewed strengthens the translational value of olive polyphenols in conditions involving cognitive dysfunction and emphasizes the novelty of new formulations.

Oneyear longitudinal study on biomarkers of blood-brain barrier permeability in COVID-19 patients

The pathophysiology behind neurological and cognitive sequelae of COVID-19 may be related to dysfunction of the blood-brain barrier (BBB) and previous research indicate transient neuronal injury and glial activation. The aim of this study was to investigate if COVID-19 is related to increased BBB permeability by analyzing leakage of biomarkers such as astrocyte-derived extracellular vesicles (EVs) and S100B. We also investigated whether levels of these biomarkers correlated with self-reported symptoms that persisted > 2 months. The samples in this 1-year follow-up study came from an ongoing longitudinal study of unvaccinated patients hospitalized for COVID-19 at Danderyd University Hospital, Stockholm, Sweden, between April and June 2020. Blood samples were collected at baseline and 4, 8, and 12 months after hospitalization. Information on self-reported clinical symptoms was collected at follow-up visits. A total of 102 patients were enrolled, and 47 completed all follow-up measurements. Peak levels of both biomarkers were observed at 4 months in the subset of 55 patients who were measured at this timepoint. At 12 months, the biomarkers had returned to baseline levels. The biomarkers were not correlated with any of the long-term self-reported symptoms. COVID-19 is associated with transient increased BBB permeability, shown by elevated levels of astrocyte biomarkers in plasma. However, these levels return to baseline 12 months post-infection and do not correlate with long-term symptoms. Further research is needed to unravel the underlying mechanisms causing long-term symptoms in COVID-19 patients.

Reactive Astrocytosis-A Potential Contributor to Increased Suicide in Long COVID-19 Patients?

BACKGROUND

Long COVID-19 is an emerging chronic illness of significant public health concern due to a myriad of neuropsychiatric sequelae, including increased suicidal ideation (SI) and behavior (SB).

METHODS

This review provides a concise synthesis of clinical evidence that points toward the dysfunction of astrocytes, the most abundant glial cell type in the central nervous system, as a potential shared pathology between SI/SB and COVID-19.

RESULTS

Depression, a suicide risk factor, and SI/SB were both associated with reduced frequencies of various astrocyte subsets and complex proteomic/transcriptional changes of astrocyte-related markers in a brain-region-specific manner. Astrocyte-related circulating markers were increased in depressed subjects and, to a less consistent extent, in COVID-19 patients. Furthermore, reactive astrocytosis was observed in subjects with SI/SB and those with COVID-19.

CONCLUSIONS

Astrocyte dysfunctions occurred in depression, SI/SB, and COVID-19. Reactive-astrocyte-mediated loss of the blood-brain barrier (BBB) integrity and subsequent neuroinflammation-a factor previously linked to SI/SB development-might contribute to increased suicide in individuals with long COVID-19. As such, the formulation of new therapeutic strategies to restore astrocyte homeostasis, enhance BBB integrity, and mitigate neuroinflammation may reduce SI/SB-associated neuropsychiatric manifestations among long COVID-19 patients.

Exploring the role of galectin-9 and artemin as biomarkers in long COVID with chronic fatigue syndrome: links to inflammation and cognitive function

This study aimed to assess plasma galectin-9 (Gal-9) and artemin (ARTN) concentrations as potential biomarkers to differentiate individuals with Long COVID (LC) patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) from SARS-CoV-2 recovered (R) and healthy controls (HCs). Receiver operating characteristic (ROC) curve analysis determined a cut-off value of plasma Gal-9 and ARTN to differentiate LC patients from the R group and HCs in two independent cohorts. Positive correlations were observed between elevated plasma Gal-9 levels and inflammatory markers (e.g. SAA and IP-10), as well as sCD14 and I-FABP in LC patients. Gal-9 also exhibited a positive correlation with cognitive failure scores, suggesting its potential role in cognitive impairment in LC patients with ME/CFS. This study highlights plasma Gal-9 and/or ARTN as sensitive screening biomarkers for discriminating LC patients from controls. Notably, the elevation of LPS-binding protein in LC patients, as has been observed in HIV infected individuals, suggests microbial translocation. However, despite elevated Gal-9, we found a significant decline in ARTN levels in the plasma of people living with HIV (PLWH). Our study provides a novel and important role for Gal-9/ARTN in LC pathogenesis.

Impact of a tailored exercise regimen on physical capacity and plasma proteome profile in post-COVID-19 condition

Background

Individuals affected by the post-covid condition (PCC) show an increased fatigue and the so-called post-exertion malaise (PEM) that led health professionals to advise against exercise although accumulating evidence indicates the contrary. The goal of this study is to determine the impact of a closely monitored 8-week mixed exercise program on physical capacity, symptoms, fatigue, systemic oxidative stress and plasma proteomic profiles of PCC cases.

Methods

Twenty-five women and men with PCC were assigned sequentially to exercise (n = 15) and non-exercise (n = 10) groups. Individuals with no PCC served as a control group. The exercise program included cardiovascular and resistance exercises. Physical capacity, physical activity level and the presence of common PCC symptoms were measured before and after the intervention. Fatigue was measured the day following each exercise session. Plasma and PBMC samples were collected at the beginning and end of the training program. Glutathione and deoxyguanosine levels in PBMC and plasma proteomic profiles were evaluated.

Results

Bicep Curl (+15% vs 4%; p = 0.040) and Sit-to-Stand test (STS-30 (+31% vs +11%; p = 0.043)) showed improvement in the exercise group when compared to the non-exercise group. An interaction effect was also observed for the level of physical activity (p =0.007) with a positive effect of the program on their daily functioning and without any adverse effects on general or post-effort fatigue. After exercise, glutathione levels in PBMCs increased in women but remained unchanged in men. Discernable changes were observed in the plasma proteomics profile with certain proteins involved in inflammatory response decreasing in the exercise group.

Conclusions

Supervised exercise adapted to the level of fatigue and ability is safe and effective in PCC patients in improving their general physical capacity and wellbeing. Systemic molecular markers that accompany physical improvement can be monitored by analyzing plasma proteomics and markers of oxidative stress. Large-scale studies will help identify promising molecular markers to objectively monitor patient improvement.

A pilot study to assess blood-brain barrier permeability in long COVID

The etiology of brain fog associated with long COVID is not clear. Based on some preliminary work, disruption of the blood-brain barrier has been hypothesized, but has not been tested in patients with long COVID. In this case-control pilot study, we evaluated blood-brain barrier permeability in patients with long COVID and subjective memory loss or brain fog. We used 99 m Technetium diethylenetriaminepentaacetic acid single-photon emission computed tomography (SPECT) to measure blood-brain barrier permeability and a telephone assessment (T-cog) to measure cognitive function. The blood-brain barrier permeability was quantified via SPECT standard uptake value (SUV). We assessed the blood-brain barrier permeability in 14 long COVID patients and 10 control participants without subjective cognitive impairment or brain fog. Participants in the two groups were similar in age. The long COVID group had more comorbidities compared to the control group. There was no difference in the SUVs in the long COVID (0.22 ± 0.12) vs the control (0.17 ± 0.04) group. There was no difference in the T-cog results in the two groups either. We found no evidence of a difference in blood-brain permeability in patients with long COVID when compared to controls without a known history of COVID-19 infection. Larger studies are needed to confirm these findings.

Cerebellitis following COVID-19 infection: A case-based systematic review and pooled analysis

Background

The COVID-19 pandemic has been linked to neurological complications, including Cerebellitis. This study aims to investigate the clinical features, and consequences of Cerebellitis following COVID-19 infection, informing medical management strategies.

Methods

A systematic search was conducted through PubMed, Web of Science, Embase, ProQuest, and Cochrane databases from January 2018 to September 12, 2023, on cases post-COVID-19. Demographics, clinical characteristics, and diagnostic techniques were analyzed using descriptive statistics. Chi-Square tests assessed associations between diagnoses and treatments, with visualizations including heatmaps and scatter plots.

Results

After the final Screening, the analysis of 18 cases revealed Cerebellitis post-COVID-19 spanned 9 countries, predominantly from the USA (27.8 %), with a mean patient age of 40.1 years (±24.6). Males comprised 94.4 % of cases. Common underlying conditions included hypertension (22.2 %) and diabetes (11.1 %). Neurological symptoms presented on average 15.15 ± 12.7 days post-COVID-19 infection. A moderate negative correlation (r = -0.358) was observed between age and symptom onset. Blood and CSF biomarkers showed weak correlations with symptom onset intervals. Treatment efficacy varied, with most cases achieving symptom-free outcomes. The Chi-Square test for diagnosis-treatment associations yielded a p-value of 0.089, and for follow-up outcomes, a p-value of 0.283, indicating no significant statistical associations.

Conclusion

This systematic review highlights increased reports of Cerebellitis in males in their fourth decade of life, with the highest comorbidities being vascular diseases. Marker assessments show a decrease in CSF protein in half of patients, along with complete recovery following combination treatment with antivirals and steroids in acute Cerebellitis.

Inhibition of mannan-binding lectin associated serine protease (MASP)-2 reduces the cognitive deficits in a mouse model of severe traumatic brain injury

The lectin pathway (LP) of complement mediates inflammatory processes linked to tissue damage and loss of function following traumatic brain injury (TBI). LP activation triggers a cascade of proteolytic events initiated by LP specific enzymes called MASPs (for Mannan-binding lectin Associated Serine Proteases). Elevated serum and brain levels of MASP-2, the effector enzyme of the LP, were previously reported to be associated with the severity of tissue injury and poor outcomes in patients with TBI. To evaluate the therapeutic potential of LP inhibition in TBI, we first conducted a pilot study testing the effect of an inhibitory MASP-2 antibody (α-MASP-2), administered systemically at 4 and 24 h post-TBI in a mouse model of controlled cortical impact (CCI). Treatment with α-MASP-2 reduced sensorimotor and cognitive deficits for up to 5 weeks post-TBI. As previous studies by others postulated a critical role of MASP-1 in LP activation, we conducted an additional study that also assessed treatment with an inhibitory MASP-1 antibody (α-MASP-1). A total of 78 mice were treated intraperitoneally with either α-MASP-2, or α-MASP-1, or an isotype control antibody 4 h and 24 h after TBI or sham injury. An amelioration of the cognitive deficits assessed by Barnes Maze, prespecified as the primary study endpoint, was exclusively observed in the α-MASP-2-treated group. The behavioral data were paralleled by a reduction of the lesion size when evaluated histologically and by reduced systemic LP activity. Our data suggest that inhibition of the LP effector enzyme MASP-2 is a promising treatment strategy to limit neurological deficits and tissue loss following TBI. Our work has translational value because a MASP-2 antibody has already completed multiple late-stage clinical trials in other indications and we used a clinically relevant treatment protocol testing the therapeutic mechanism of MASP-2 inhibition in TBI.

COVID-19: Unveiling the Neuropsychiatric Maze-From Acute to Long-Term Manifestations

The SARS-CoV-2 virus has spread rapidly despite implementing strategies to reduce its transmission. The disease caused by this virus has been associated with a diverse range of symptoms, including common neurological manifestations such as dysgeusia, anosmia, and myalgias. Additionally, numerous cases of severe neurological complications associated with this disease have been reported, including encephalitis, stroke, seizures, and Guillain-Barré syndrome, among others. Given the high prevalence of neurological manifestations in this disease, the objective of this review is to analyze the mechanisms by which this virus can affect the nervous system, from its direct invasion to aberrant activation of the immune system and other mechanisms involved in the symptoms, including neuropsychiatric manifestations, to gain a better understanding of the disease and thus facilitate the search for effective therapeutic strategies.

Engineered Wnt7a ligands rescue blood-brain barrier and cognitive deficits in a COVID-19 mouse model

Respiratory infection with SARS-CoV-2 causes systemic vascular inflammation and cognitive impairment. We sought to identify the underlying mechanisms mediating cerebrovascular dysfunction and inflammation following mild respiratory SARS-CoV-2 infection. To this end, we performed unbiased transcriptional analysis to identify brain endothelial cell signalling pathways dysregulated by mouse adapted SARS-CoV-2 MA10 in aged immunocompetent C57Bl/6 mice in vivo. This analysis revealed significant suppression of Wnt/β-catenin signalling, a critical regulator of blood-brain barrier (BBB) integrity. We therefore hypothesized that enhancing cerebrovascular Wnt/β-catenin activity would offer protection against BBB permeability, neuroinflammation, and neurological signs in acute infection. Indeed, we found that delivery of cerebrovascular-targeted, engineered Wnt7a ligands protected BBB integrity, reduced T-cell infiltration of the brain, and reduced microglial activation in SARS-CoV-2 infection. Importantly, this strategy also mitigated SARS-CoV-2 induced deficits in the novel object recognition assay for learning and memory and the pole descent task for bradykinesia. These observations suggest that enhancement of Wnt/β-catenin signalling or its downstream effectors could be potential interventional strategies for restoring cognitive health following viral infections.

Serum detection of blood brain barrier injury in subjects with a history of stroke and transient ischemic attack

Objective

Stroke and transient ischemic attack may have long-term negative effects on the blood-brain barrier (BBB) and promote endothelial inflammation, both of which could increase neurodegeneration and dementia risk beyond the cell death associated with the index event.

Methods

Serum from 88 postmortem subjects in the Arizona Study of Aging and Neurodegenerative Disorders were analyzed by sandwich ELISA for specific biomarkers to investigate the effects of cerebrovascular accidents (CVAs) on BBB integrity and endothelial activation. Statistical analyses were performed using the Mann-Whitney U Test, Spearman rank correlation, and linear/logistic regressions adjusted for potential confounders; a P-value < .05 was considered significant for all analyses.

Results

Serum PDGFRẞ, a putative biomarker of BBB injury, was significantly increased in subjects with vs without a history of CVA who had similar cardiovascular risk factors (P < .01). This difference was stable after adjusting for age, hypertension, and other potential confounders in regression analysis (odds ratio, 27.02; 95% confidence interval, 2.61-411.7; P < .01). In addition, PDGFRẞ was positively associated with VCAM-1, a biomarker of endothelial inflammation (ρ = 0.42; P < .01).

Conclusions

Our data suggest that patients with stroke or transient ischemic attack have lasting changes in the BBB. Still more, this demonstrates the utility of PDGFRẞ as a serum-based biomarker of BBB physiology, a potentially powerful tool in studying the role of the BBB in various neurodegenerative diseases and COVID infection sequelae.

Clinical Relevance

Our data demonstrate the utility of serum PDGFRẞ, a putative biomarker of BBB integrity in the setting of stroke and TIA (CVA). A serum biomarker of BBB integrity could be a useful tool to detect early BBB damage and allow prospective work to study how such damage affects long-term neurodegenerative risk. Since BBB disruption occurs early in ADRD development, it could be monitored to help better understand disease progression and involvement of vascular pathways in ADRD.

Blood-brain barrier biomarkers

The blood-brain barrier (BBB) is a dynamic interface that regulates the exchange of molecules and cells between the brain parenchyma and the peripheral blood. The BBB is mainly composed of endothelial cells, astrocytes and pericytes. The integrity of this structure is essential for maintaining brain and spinal cord homeostasis and protection from injury or disease. However, in various neurological disorders, such as traumatic brain injury, Alzheimer's disease, and multiple sclerosis, the BBB can become compromised thus allowing passage of molecules and cells in and out of the central nervous system parenchyma. These agents, however, can serve as biomarkers of BBB permeability and neuronal damage, and provide valuable information for diagnosis, prognosis and treatment. Herein, we provide an overview of the BBB and changes due to aging, and summarize current knowledge on biomarkers of BBB disruption and neurodegeneration, including permeability, cellular, molecular and imaging biomarkers. We also discuss the challenges and opportunities for developing a biomarker toolkit that can reliably assess the BBB in physiologic and pathophysiologic states.

Mast cells in the autonomic nervous system and potential role in disorders with dysautonomia and neuroinflammation

Mast cells (MC) are ubiquitous in the body, and they are critical for not only in allergic diseases but also in immunity and inflammation, including having potential involvement in the pathophysiology of dysautonomias and neuroinflammatory disorders. MC are located perivascularly close to nerve endings and sites such as the carotid bodies, heart, hypothalamus, the pineal gland, and the adrenal gland that would allow them not only to regulate but also to be affected by the autonomic nervous system (ANS). MC are stimulated not only by allergens but also many other triggers including some from the ANS that can affect MC release of neurosensitizing, proinflammatory, and vasoactive mediators. Hence, MC may be able to regulate homeostatic functions that seem to be dysfunctional in many conditions, such as postural orthostatic tachycardia syndrome, autism spectrum disorder, myalgic encephalomyelitis/chronic fatigue syndrome, and Long-COVID syndrome. The evidence indicates that there is a possible association between these conditions and diseases associated with MC activation. There is no effective treatment for any form of these conditions other than minimizing symptoms. Given the many ways MC could be activated and the numerous mediators released, it would be important to develop ways to inhibit stimulation of MC and the release of ANS-relevant mediators.

Caveolin-1 mediates blood-brain barrier permeability, neuroinflammation, and cognitive impairment in SARS-CoV-2 infection

Blood-brain barrier (BBB) permeability can cause neuroinflammation and cognitive impairment. Caveolin-1 (Cav-1) critically regulates BBB permeability, but its influence on the BBB and consequent neurological outcomes in respiratory viral infections is unknown. We used Cav-1-deficient mice with genetically encoded fluorescent endothelial tight junctions to determine how Cav-1 influences BBB permeability, neuroinflammation, and cognitive impairment following respiratory infection with mouse adapted (MA10) SARS-CoV-2 as a model for COVID-19. We found that SARS-CoV-2 infection increased brain endothelial Cav-1 and increased transcellular BBB permeability to albumin, decreased paracellular BBB Claudin-5 tight junctions, and caused T lymphocyte infiltration in the hippocampus, a region important for learning and memory. Concordantly, we observed learning and memory deficits in SARS-CoV-2 infected mice. Importantly, genetic deficiency in Cav-1 attenuated transcellular BBB permeability and paracellular BBB tight junction losses, T lymphocyte infiltration, and gliosis induced by SARS-CoV-2 infection. Moreover, Cav-1 KO mice were protected from the learning and memory deficits caused by SARS-CoV-2 infection. These results establish the contribution of Cav-1 to BBB permeability and behavioral dysfunction induced by SARS-CoV-2 neuroinflammation.

Systemic inflammation relates to neuroaxonal damage associated with long-term cognitive dysfunction in COVID-19 patients

BACKGROUND AND OBJECTIVES

Cognitive deficits are increasingly recognized as a long-term sequela of severe COVID-19. The underlying processes and molecular signatures associated with these long-term neurological sequalae of COVID-19 remain largely unclear, but may be related to systemic inflammation-induced effects on the brain. We studied the systemic inflammation-brain interplay and its relation to development of long-term cognitive impairment in patients who survived severe COVID-19. Trajectories of systemic inflammation and neuroaxonal damage blood biomarkers during ICU admission were analyzed and related to long-term cognitive outcomes.

METHODS

Prospective longitudinal cohort study of patients with severe COVID-19 surviving ICU admission. During admission, blood was sampled consecutively to assess levels of inflammatory cytokines and neurofilament light chain (NfL) using an ultrasensitive multiplex Luminex assay and single molecule array technique (Simoa). Cognitive functioning was evaluated using a comprehensive neuropsychological assessment six months after ICU-discharge.

RESULTS

Ninety-six patients (median [IQR] age 61 [55-69] years) were enrolled from March 2020 to June 2021 and divided into two cohorts: those who received no COVID-19-related immunotherapy (n = 28) and those treated with either dexamethasone or dexamethasone and tocilizumab (n = 68). Plasma NfL concentrations increased in 95 % of patients during their ICU stay, from median [IQR] 23 [18-38] pg/mL at admission to 250 [160-271] pg/mL after 28 days, p < 0.001. Besides age, glomerular filtration rate, immunomodulatory treatment, and C-reactive protein, more specific markers of systemic inflammation at day 14 (i.e., interleukin (IL)-8, tumour necrosis factor, and IL-1 receptor antagonist) were significant predictors of blood NfL levels at day 14 of ICU admission (R2 = 44 %, p < 0.001), illustrating the association between sustained systemic inflammation and neuroaxonal damage. Twenty-six patients (27 %) exhibited cognitive impairment six months after discharge from the ICU. NfL concentrations showed a more pronounced increase in patients that developed cognitive impairment (p = 0.03). Higher NfL predicted poorer outcome in information processing speed (Trail Making Test A, r = -0.26, p = 0.01; Letter Digit Substitution Test, r = -0.24, p = 0.02).

DISCUSSION

Prolonged systemic inflammation in critically ill COVID-19 patients is related to neuroaxonal damage and subsequent long-term cognitive impairment. Moreover, our findings suggest that plasma NfL concentrations during ICU stay may possess prognostic value in predicting future long-term cognitive impairment in patients that survived severe COVID-19.

COVID-19-associated serum and cerebrospinal fluid cytokines in post- versus para-infectious SARS-CoV-2-related Guillain-Barré syndrome

INTRODUCTION

Guillain-Barré syndrome associated with Coronavirus-2-related severe acute respiratory syndrome (COV-GBS) occurs as para- or post-infectious forms, depending on the timing of disease onset. In these two forms, we aimed to compare the cerebrospinal fluid (CSF) and serum proinflammatory cytokine profiles to evaluate differences that could possibly have co-pathogenic relevance.

MATERIALS AND METHODS

We studied a retrospective cohort of 26 patients with either post-COV-GBS (n = 15), with disease onset occurring > 7 days after SARS-CoV-2 infection, or para-COV-GBS (n = 11), with disease onset 7 days or less. TNF-α, IL-6, and IL-8 were measured in the serum with SimplePlex™ Ella™ immunoassay. In addition to the para-/post-COV-GBS patients, serum levels of these cytokines were determined in those with non-COVID-associated-GBS (NC-GBS; n = 43), paucisymptomatic SARS-CoV-2 infection without GBS (COVID, n = 20), and in healthy volunteers (HV; n = 12). CSF cytokine levels were measured in patients with para-/post-COV-GBS, in those with NC-GBS (n = 29), or with Alzheimer's disease (AD; n = 24).

RESULTS

Serum/CSF cytokine levels did not differ in para- vs post-COV-GBS. We found that SARS-CoV-2 infection raises the serum levels of TNF-α, IL-6, and IL-8, as well as an increase of IL-6 (in serum and CSF) and IL-8 (in CSF) in either NC-GBS or COV-GBS than controls. CSF and serum cytokine levels resulted independent one with another.

CONCLUSIONS

The change of cytokines linked to SARS-CoV-2 in COV-GBS appears to be driven by viral infection, although it has unique characteristics in GBS as such and does not account for cases with para- or post-infectious onset.

Proteomic and transcriptomic profiling of brainstem, cerebellum and olfactory tissues in early- and late-phase COVID-19

Neurological symptoms, including cognitive impairment and fatigue, can occur in both the acute infection phase of coronavirus disease 2019 (COVID-19) and at later stages, yet the mechanisms that contribute to this remain unclear. Here we profiled single-nucleus transcriptomes and proteomes of brainstem tissue from deceased individuals at various stages of COVID-19. We detected an inflammatory type I interferon response in acute COVID-19 cases, which resolves in the late disease phase. Integrating single-nucleus RNA sequencing and spatial transcriptomics, we could localize two patterns of reaction to severe systemic inflammation, one neuronal with a direct focus on cranial nerve nuclei and a separate diffuse pattern affecting the whole brainstem. The latter reflects a bystander effect of the respiratory infection that spreads throughout the vascular unit and alters the transcriptional state of mainly oligodendrocytes, microglia and astrocytes, while alterations of the brainstem nuclei could reflect the connection of the immune system and the central nervous system via, for example, the vagus nerve. Our results indicate that even without persistence of severe acute respiratory syndrome coronavirus 2 in the central nervous system, local immune reactions are prevailing, potentially causing functional disturbances that contribute to neurological complications of COVID-19.

The S1 subunits of SARS-CoV-2 variants differentially trigger the IL-6 signaling pathway in human brain endothelial cells and downstream impact on microglia activation

Objectives

Cerebrovascular complications are prevalent in COVID-19 infection and post-COVID conditions; therefore, interactions of SARS-CoV-2 with cerebral microvascular cells became an emerging concern.

Methods

We examined the inflammatory responses of human brain microvascular endothelial cells (HBMEC), the main structural element of the blood-brain barrier (BBB), following exposure to the S1 subunit of the spike protein of different SARS-CoV-2 variants. Specifically, we used the S1 subunit derived from the D614 variant of SARS-CoV-2, which started widely circulating in March of 2020, and from the Delta variant, which started widely circulating in early 2021. We then further examined the impact of the HBMEC secretome, produced in response to the S1 exposure, on microglial proinflammatory responses.

Results

Treatment with S1 derived from the D614 variant and from the Delta variant resulted in differential alterations of the IL-6 signaling pathway. Moreover, the HBMEC secretome obtained after exposure to the S1 subunit of the D614 variant activated STAT3 in microglial cells, indicating that proinflammatory signals from endothelial cells can propagate to other cells of the neurovascular unit. Overall, these results indicate the potential for different SARS-CoV-2 variants to induce unique cellular signatures and warrant individualized treatment strategies. The findings from this study also bring further awareness to proinflammatory responses involving brain microvasculature in COVID-19 and demonstrate how the surrounding microglia react to each unique variant derived response.

Amyotrophic Lateral Sclerosis in Long-COVID Scenario and the Therapeutic Potential of the Purinergic System in Neuromodulation

Amyotrophic lateral sclerosis (ALS) involves the degeneration of motor neurons and debilitating and possibly fatal symptoms. The COVID-19 pandemic directly affected the quality of life of this group, and the SARS-CoV-2 infection accelerated the present neuroinflammatory process. Furthermore, studies indicate that the infection may have led to the development of the pathology. Thus, the scenario after this pandemic presents "long-lasting COVID" as a disease that affects people who have been infected. From this perspective, studying the pathophysiology behind ALS associated with SARS-CoV-2 infection and possible supporting therapies becomes necessary when we understand the impact on the quality of life of these patients. Thus, the purinergic system was trained to demonstrate how its modulation can add to the treatment, reduce disease progression, and result in better prognoses. From our studies, we highlight the P2X7, P2X4, and A2AR receptors and how their activity can directly influence the ALS pathway.

A Prospective Multicenter Longitudinal Analysis of Suicidal Ideation among Long-COVID-19 Patients

Long coronavirus disease 19 (COVID-19) is an emerging multifaceted illness with the pathological hallmarks of chronic inflammation and neuropsychiatric symptoms. These pathologies have also been implicated in developing suicidal behaviors and suicidal ideation (SI). However, research addressing suicide risk in long COVID-19 is limited. In this prospective study, we aim to characterize SI development among long-COVID-19 patients and to determine the predictive power of inflammatory markers and long-COVID-19 symptoms-including those of psychiatric origin-for SI. During this prospective, longitudinal, multicenter study, healthy subjects and long-COVID-19 patients will be recruited from the University Hospital of Geneva, Switzerland, the University of Genova, the University of Rome "La Sapienza", and the University of San Francisco. Study participants will undergo a series of clinic visits over a follow-up period of 1 year for SI assessment. Baseline and SI-onset levels of inflammatory mediators in plasma samples, along with 12 long-COVID-19 features (post-exertional malaise, fatigue, brain fog, dizziness, gastrointestinal disturbance, palpitations, changes in sexual desire/capacity, loss/change of smell/taste, thirst, chronic cough, chest pain, and abnormal movements) will be collected for SI risk analysis. The proposed enrollment period is from 15 January 2024 to 15 January 2026 with targeted recruitment of 100 participants for each study group. The anticipated findings of this study are expected to provide important insights into suicide risk among long-COVID-19 patients and determine whether inflammation and psychiatric comorbidities are involved in the development of SI in these subjects. This could pave the way to more effective evidence-based suicide prevention approaches to address this emerging public health concern.

Systematic review and evidence gap mapping of biomarkers associated with neurological manifestations in patients with COVID-19

OBJECTIVE

This study aimed to synthesize the existing evidence on biomarkers related to coronavirus disease 2019 (COVID-19) patients who presented neurological events.

METHODS

A systematic review of observational studies (any design) following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and the Cochrane Collaboration recommendations was performed (PROSPERO: CRD42021266995). Searches were conducted in PubMed and Scopus (updated April 2023). The methodological quality of nonrandomized studies was assessed using the Newcastle‒Ottawa Scale (NOS). An evidence gap map was built considering the reported biomarkers and NOS results.

RESULTS

Nine specific markers of glial activation and neuronal injury were mapped from 35 studies published between 2020 and 2023. A total of 2,237 adult patients were evaluated in the included studies, especially during the acute phase of COVID-19. Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) biomarkers were the most frequently assessed (n = 27 studies, 77%, and n = 14 studies, 40%, respectively). Although these biomarkers were found to be correlated with disease severity and worse outcomes in the acute phase in several studies (p < 0.05), they were not necessarily associated with neurological events. Overall, 12 studies (34%) were judged as having low methodological quality, 9 (26%) had moderate quality, and 9 (26%) had high quality.

CONCLUSIONS

Different neurological biomarkers in neurosymptomatic COVID-19 patients were identified in observational studies. Although the evidence is still scarce and conflicting for some biomarkers, well-designed longitudinal studies should further explore the pathophysiological role of NfL, GFAP, and tau protein and their potential use for COVID-19 diagnosis and management.

The neurobiology of SARS-CoV-2 infection

Worldwide, over 694 million people have been infected with SARS-CoV-2, with an estimated 55-60% of those infected developing COVID-19. Since the beginning of the pandemic in December 2019, different variants of concern have appeared and continue to occur. With the emergence of different variants, an increasing rate of vaccination and previous infections, the acute neurological symptomatology of COVID-19 changed. Moreover, 10-45% of individuals with a history of SARS-CoV-2 infection experience symptoms even 3 months after disease onset, a condition that has been defined as 'post-COVID-19' by the World Health Organization and that occurs independently of the virus variant. The pathomechanisms of COVID-19-related neurological complaints have become clearer during the past 3 years. To date, there is no overt - that is, truly convincing - evidence for SARS-CoV-2 particles in the brain. In this Review, we put special emphasis on discussing the  methodological difficulties of viral detection in CNS tissue and discuss immune-based (systemic and central) effects contributing to COVID-19-related CNS affection. We sequentially review the reported changes to CNS cells in COVID-19, starting with the blood-brain barrier and blood-cerebrospinal fluid barrier - as systemic factors from the periphery appear to primarily influence barriers and conduits - before we describe changes in brain parenchymal cells, including microglia, astrocytes, neurons and oligodendrocytes as well as cerebral lymphocytes. These findings are critical to understanding CNS affection in acute COVID-19 and post-COVID-19 in order to translate these findings into treatment options, which are still very limited.

Elevated matrix metalloproteinase‑9 expression is associated with COVID‑19 severity: A meta‑analysis

The present meta-analysis investigated the clinical value of serum matrix metalloproteinase (MMP)-9 levels in Coronavirus Disease 2019 (COVID-19) patients. Studies assessing the outcomes of patients with COVID-19 in correlation with the MMP-9 levels were retrieved from PubMed, Web of Science, EMBASE, Cochrane, WANFANG, and CNKI. A meta-analysis was performed to compare the serum MMP-9 levels between different patient groups: Severe vs. non-severe; acute respiratory distress syndrome (ARDS) vs. non-ARDS; non-survivors vs. survivors; neurologic syndrome vs. non-neurologic syndrome; and obese diabetic vs. non-obese diabetic. A total of 2,062 COVID-19-confirmed patients from 12 studies were included in this meta-analysis. The serum MMP-9 levels were significantly higher in patients with severe COVID-19 than in those with non-severe COVID-19 [weighted mean difference (WMD) 246.61 (95% confidence interval (CI), 115.86-377.36), P<0.001]. Patients with ARDS exhibited significantly higher MMP-9 levels than those without ARDS [WMD 248.55 (95% CI, 63.84-433.25), P<0.001]. The MMP-9 levels in the non-survivors did not significantly differ from those in the survivors [WMD 37.79 (95% CI, -18.08-93.65), P=0.185]. Patients with comorbidities, including neurological syndromes, and obese diabetic patients had significantly higher MMP-9 levels than those without comorbidities [WMD 170.73 (95% CI, 95.61-245.85), P<0.001]. Serum MMP-9 levels were associated with COVID-19 severity and may serve as a therapeutic target for improving the prognosis of patients with COVID-19.

Blood-brain barrier breakdown in COVID-19 ICU survivors: an MRI pilot study

Objectives

Coronavirus disease 2019 (COVID-19) results in severe inflammation at the acute stage. Chronic neuroinflammation and abnormal immunological response have been suggested to be the contributors to neuro-long-COVID, but direct evidence has been scarce. This study aims to determine the integrity of the blood-brain barrier (BBB) in COVID-19 intensive care unit (ICU) survivors using a novel MRI technique.

Methods

COVID-19 ICU survivors (n=7) and age and sex-matched control participants (n=17) were recruited from June 2021 to March 2023. None of the control participants were hospitalized due to COVID-19 infection. The COVID-19 ICU survivors were studied at 98.6 ± 14.9 days after their discharge from ICU. A non-invasive MRI technique was used to assess the BBB permeability to water molecules, in terms of permeability surface area-product (PS) in the units of mL/100 g/min.

Results

PS was significantly higher in COVID-19 ICU survivors (p=0.038) when compared to the controls, with values of 153.1 ± 20.9 mL/100 g/min and 132.5 ± 20.7 mL/100 g/min, respectively. In contrast, there were no significant differences in whole-brain cerebral blood flow (p=0.649) or brain volume (p=0.471) between the groups.

Conclusions

There is preliminary evidence of a chronic BBB breakdown in COVID-19 survivors who had a severe acute infection, suggesting a plausible contributor to neurological long-COVID symptoms.

Blood Biomarkers as Prognostic Indicators for Neurological Injury in COVID-19 Patients: A Systematic Review and Meta-Analysis

Coronavirus disease 2019 (COVID-19) has been linked to various neurological complications. This meta-analysis assessed the relationship between glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) levels in the blood and neurological injury in COVID-19 patients. A comprehensive search of various databases was conducted until 18 August 2023, to find studies reporting GFAP and NfL blood levels in COVID-19 patients with neurological complications. GFAP and NfL levels were estimated between COVID-19 patients and healthy controls, and meta-analyses were performed using RevMan 5.4 software for analysis. In the 21 collected studies, it was found that COVID-19 patients had significantly higher levels of pooled GFAP (SMD = 0.52; 95% CI: 0.31, 0.73; p ≤ 0.001) and NfL (SMD = 0.60; 95% CI: 0.37, 0.82; p ≤ 0.001) when compared to the healthy controls. The pooled GFAP (SMD = 0.86; 95% CI: 0.26, 1.45; p ≤ 0.01) and NfL (SMD = 0.87; 95% CI: 0.48, 1.26; p ≤ 0.001) were significantly higher in non-survivors. These findings indicate a significant association between COVID-19 severity and elevated levels of GFAP and NfL, suggesting that GFAP and NfL could serve as potential diagnostic and prognostic markers for the early detection and monitoring of COVID-19-related neurological injuries.

Proteomic Analysis Reveals Novel Plasma Biomarkers for Neurological Complications in Patients With Congenital Cytomegalovirus Infection

BACKGROUND

Congenital cytomegalovirus (cCMV) infection is a leading cause of nonhereditary neurological complications. When considering antiviral treatment, it is important to differentiate between symptomatic and asymptomatic patients. This study aimed to identify candidate plasma biomarkers for neurological complications of cCMV infection using proteomic analysis.

METHODS

This study retrospectively enrolled five patients with symptomatic cCMV infection, four with asymptomatic cCMV infection with isolated sensorineural hearing loss (SNHL), and five with asymptomatic cCMV infection. The plasma samples were collected during neonatal period. The peptides were analyzed using liquid chromatography-mass spectrometry. The concentrations of differentially expressed proteins were validated using an enzyme-linked immunosorbent assay.

RESULTS

A total of 456 proteins were identified and quantified. The levels of 80 proteins were significantly different between patients with and without cCMV-related symptoms including isolated SNHL. The levels of 31 proteins were significantly different between patients with and without neuroimaging abnormalities. The plasma concentrations of Fms-related receptor tyrosine kinase 4 in patients with cCMV-related symptoms were significantly higher than those in patients with asymptomatic cCMV infection. Moreover, plasma peptidylprolyl isomerase A levels were significantly higher in patients with neuroimaging abnormalities than in those without.

CONCLUSIONS

Proteomic analysis of patients with cCMV infection showed that Fms-related receptor tyrosine kinase 4 and peptidylprolyl isomerase A could be novel diagnostic biomarkers for neurological complications of cCMV infection.

Caveolin-1 mediates neuroinflammation and cognitive impairment in SARS-CoV-2 infection

Leukocyte infiltration of the CNS can contribute to neuroinflammation and cognitive impairment. Brain endothelial cells regulate adhesion, activation, and diapedesis of T cells across the blood-brain barrier (BBB) in inflammatory diseases. The integral membrane protein Caveolin-1 (Cav-1) critically regulates BBB permeability, but its influence on T cell CNS infiltration in respiratory viral infections is unknown. In this study, we sought to determine the role of Cav-1 at the BBB in neuroinflammation in a COVID-19 mouse model. We used mice genetically deficient in Cav-1 to test the role of this protein in T cell infiltration and cognitive impairment. We found that SARS-CoV-2 infection upregulated brain endothelial Cav-1. Moreover, SARS-CoV-2 infection increased brain endothelial cell vascular cell adhesion molecule-1 (VCAM-1) and CD3+ T cell infiltration of the hippocampus, a region important for short term learning and memory. Concordantly, we observed learning and memory deficits. Importantly, genetic deficiency in Cav-1 attenuated brain endothelial VCAM-1 expression and T cell infiltration in the hippocampus of mice with SARS-CoV-2 infection. Moreover, Cav-1 KO mice were protected from the learning and memory deficits caused by SARS-CoV-2 infection. These results indicate the importance of BBB permeability in COVID-19 neuroinflammation and suggest potential therapeutic value of targeting Cav-1 to improve disease outcomes.

Neurofilament light chain on intensive care admission is an independent predictor of mortality in COVID-19: a prospective multicenter study

BACKGROUND

Neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), and total-tau protein (tau) are novel blood biomarkers of neurological injury, and may be used to predict outcomes in critical COVID-19.

METHODS

A prospective multicentre cohort study of 117 consecutive and critically ill COVID-19 patients in six intensive care units (ICUs) in southern Sweden between May and November 2020. Serial NfL, GFAP and tau were analysed in relation to mortality, the Glasgow Outcome Scale Extended (GOSE) and the physical (PCS) and mental (MCS) components of health-related quality of life at one year.

RESULTS

NfL, GFAP and tau on ICU admission predicted one-year mortality with an area under the curve (AUC) of 0.82 (95% confidence interval [CI] 0.74[Formula: see text]0.90), 0.72 (95% CI 0.62[Formula: see text]0.82) and 0.66 (95% CI 0.54[Formula: see text]0.77). NfL on admission was an independent predictor of one-year mortality (p = 0.039). Low NfL and GFAP values were associated with good PCS ([Formula: see text]45) at one year but not with good MCS ([Formula: see text]45) or GOSE ([Formula: see text]5).

CONCLUSIONS

NfL on ICU admission was an independent predictor of mortality. High levels of NfL, GFAP and tau were associated with mortality but not with poor GOSE in survivors at one year. Low levels of NfL and GFAP were associated with improved physical health-related quality of life.

Hippocampal subfield abnormalities and biomarkers of pathologic brain changes: from SARS-CoV-2 acute infection to post-COVID syndrome

BACKGROUND

Cognitive deficits are among the main disabling symptoms in COVID-19 patients and post-COVID syndrome (PCS). Within brain regions, the hippocampus, a key region for cognition, has shown vulnerability to SARS-CoV-2 infection. Therefore, in vivo detailed evaluation of hippocampal changes in PCS patients, validated on post-mortem samples of COVID-19 patients at the acute phase, would shed light into the relationship between COVID-19 and cognition.

METHODS

Hippocampal subfields volume, microstructure, and perfusion were evaluated in 84 PCS patients and compared to 33 controls. Associations with blood biomarkers, including glial fibrillary acidic protein (GFAP), myelin oligodendrocyte glycoprotein (MOG), eotaxin-1 (CCL11) and neurofilament light chain (NfL) were evaluated. Besides, biomarker immunodetection in seven hippocampal necropsies of patients at the acute phase were contrasted against eight controls.

FINDINGS

In vivo analyses revealed that hippocampal grey matter atrophy is accompanied by altered microstructural integrity, hypoperfusion, and functional connectivity changes in PCS patients. Hippocampal structural and functional alterations were related to cognitive dysfunction, particularly attention and memory. GFAP, MOG, CCL11 and NfL biomarkers revealed alterations in PCS, and showed associations with hippocampal volume changes, in selective hippocampal subfields. Moreover, post mortem histology showed the presence of increased GFAP and CCL11 and reduced MOG concentrations in the hippocampus in post-mortem samples at the acute phase.

INTERPRETATION

The current results evidenced that PCS patients with cognitive sequalae present brain alterations related to cognitive dysfunction, accompanied by a cascade of pathological alterations in blood biomarkers, indicating axonal damage, astrocyte alterations, neuronal injury, and myelin changes that are already present from the acute phase.

FUNDING

Nominative Grant FIBHCSC 2020 COVID-19. Department of Health, Community of Madrid. Instituto de Salud Carlos III through the project INT20/00079, co-funded by European Regional Development Fund "A way to make Europe" (JAMG). Instituto de Salud Carlos III (ISCIII) through Sara Borrell postdoctoral fellowship Grant No. CD22/00043) and co-funded by the European Union (MDC). Instituto de Salud Carlos III through a predoctoral contract (FI20/000145) (co-funded by European Regional Development Fund "A way to make Europe") (MVS). Fundación para el Conocimiento Madri+d through the project G63-HEALTHSTARPLUS-HSP4 (JAMG, SOM).

Neurological manifestations of post-acute sequelae of COVID-19: which liquid biomarker should we use?

Long COVID syndrome, also known as post-acute sequelae of COVID-19 (PASC), is characterized by persistent symptoms lasting 3-12 weeks post SARS-CoV-2 infection. Patients suffering from PASC can display a myriad of symptoms that greatly diminish quality of life, the most frequent being neuropsychiatric. Thus, there is an eminent need to diagnose and treat PASC related neuropsychiatric manifestation (neuro-PASC). Evidence suggests that liquid biomarkers could potentially be used in the diagnosis and monitoring of patients. Undoubtedly, such biomarkers would greatly benefit clinicians in the management of patients; however, it remains unclear if these can be reliably used in this context. In this mini review, we highlight promising liquid (blood and cerebrospinal fluid) biomarkers, namely, neuronal injury biomarkers NfL, GFAP, and tau proteins as well as neuroinflammatory biomarkers IL-6, IL-10, TNF-α, and CPR associated with neuro-PASC and discuss their limitations in clinical applicability.

Neurofilament Expression as a Biomarker of Post-COVID-19 Sudden Sensorineural Hearing Loss

Sudden sensorineural hearing loss (SSHL) affects a patient's quality of life and requires rapid treatment. The etiology is viral, vascular, and autoimmune, even though, in most cases, it remains idiopathic SSHL. Since 2019, several different complications have been identified following COVID-19 infection. The post-COVID-19 ENT manifestations reported in the literature are sore throat, headache, pharyngeal erythema, nasal obstruction, rhinorrhea, upper respiratory tract infection, and tonsil enlargement. Cases of SSHL, vestibular neuronitis, and audio-vestibular disorders (such as tinnitus, dizziness, and vertigo) have also been reported, albeit in a smaller percentage of patients. We reported our experience of a case of post-COVID-19 SSHL in the absence of any other type of post-COVID symptoms or brain and internal auditory canal magnetic resonance imaging and magnetic resonance angiography modifications. We aimed to identify a serological biomarker of sudden sensorineural hearing loss, and we also dosed and monitored the value of the serum neurofilament light (NfL). the best of our knowledge, this is the first report that associates SSHL and the serological increase in NfL as a potential biomarker of neuronal-disease-related damage.

The role of peripheral inflammatory insults in Alzheimer's disease: a review and research roadmap

Peripheral inflammation, defined as inflammation that occurs outside the central nervous system, is an age-related phenomenon that has been identified as a risk factor for Alzheimer's disease. While the role of chronic peripheral inflammation has been well characterized in the context of dementia and other age-related conditions, less is known about the neurologic contribution of acute inflammatory insults that take place outside the central nervous system. Herein, we define acute inflammatory insults as an immune challenge in the form of pathogen exposure (e.g., viral infection) or tissue damage (e.g., surgery) that causes a large, yet time-limited, inflammatory response. We provide an overview of the clinical and translational research that has examined the connection between acute inflammatory insults and Alzheimer's disease, focusing on three categories of peripheral inflammatory insults that have received considerable attention in recent years: acute infection, critical illness, and surgery. Additionally, we review immune and neurobiological mechanisms which facilitate the neural response to acute inflammation and discuss the potential role of the blood-brain barrier and other components of the neuro-immune axis in Alzheimer's disease. After highlighting the knowledge gaps in this area of research, we propose a roadmap to address methodological challenges, suboptimal study design, and paucity of transdisciplinary research efforts that have thus far limited our understanding of how pathogen- and damage-mediated inflammatory insults may contribute to Alzheimer's disease. Finally, we discuss how therapeutic approaches designed to promote the resolution of inflammation may be used following acute inflammatory insults to preserve brain health and limit progression of neurodegenerative pathology.

Towards Novel Biomimetic In Vitro Models of the Blood-Brain Barrier for Drug Permeability Evaluation

Current available animal and in vitro cell-based models for studying brain-related pathologies and drug evaluation face several limitations since they are unable to reproduce the unique architecture and physiology of the human blood-brain barrier. Because of that, promising preclinical drug candidates often fail in clinical trials due to their inability to penetrate the blood-brain barrier (BBB). Therefore, novel models that allow us to successfully predict drug permeability through the BBB would accelerate the implementation of much-needed therapies for glioblastoma, Alzheimer's disease, and further disorders. In line with this, organ-on-chip models of the BBB are an interesting alternative to traditional models. These microfluidic models provide the necessary support to recreate the architecture of the BBB and mimic the fluidic conditions of the cerebral microvasculature. Herein, the most recent advances in organ-on-chip models for the BBB are reviewed, focusing on their potential to provide robust and reliable data regarding drug candidate ability to reach the brain parenchyma. We point out recent achievements and challenges to overcome in order to advance in more biomimetic in vitro experimental models based on OOO technology. The minimum requirements that should be met to be considered biomimetic (cellular types, fluid flow, and tissular architecture), and consequently, a solid alternative to in vitro traditional models or animals.

COVID-19, post-acute COVID-19 syndrome (PACS, "long COVID") and post-COVID-19 vaccination syndrome (PCVS, "post-COVIDvac-syndrome"): Similarities and differences

Worldwide there have been over 760 million confirmed coronavirus disease 2019 (COVID-19) cases, and over 13 billion COVID-19 vaccine doses have been administered as of April 2023, according to the World Health Organization. An infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to an acute disease, i.e. COVID-19, but also to a post-acute COVID-19 syndrome (PACS, "long COVID"). Currently, the side effects of COVID-19 vaccines are increasingly being noted and studied. Here, we summarise the currently available indications and discuss our conclusions that (i) these side effects have specific similarities and differences to acute COVID-19 and PACS, that (ii) a new term should be used to refer to these side effects (post-COVID-19 vaccination syndrome, PCVS, colloquially "post-COVIDvac-syndrome"), and that (iii) there is a need to distinguish between acute COVID-19 vaccination syndrome (ACVS) and post-acute COVID-19 vaccination syndrome (PACVS) - in analogy to acute COVID-19 and PACS ("long COVID"). Moreover, we address mixed forms of disease caused by natural SARS-CoV-2 infection and COVID-19 vaccination. We explain why it is important for medical diagnosis, care and research to use the new terms (PCVS, ACVS and PACVS) in order to avoid confusion and misinterpretation of the underlying causes of disease and to enable optimal medical therapy. We do not recommend to use the term "Post-Vac-Syndrome" as it is imprecise. The article also serves to address the current problem of "medical gaslighting" in relation to PACS and PCVS by raising awareness among the medical professionals and supplying appropriate terminology for disease.

Hypertonic sodium lactate infusion reduces vasopressor requirements and biomarkers of brain and cardiac injury after experimental cardiac arrest

INTRODUCTION

Prognosis after resuscitation from cardiac arrest (CA) remains poor, with high morbidity and mortality as a result of extensive cardiac and brain injury and lack of effective treatments. Hypertonic sodium lactate (HSL) may be beneficial after CA by buffering severe metabolic acidosis, increasing brain perfusion and cardiac performance, reducing cerebral swelling, and serving as an alternative energetic cellular substrate. The aim of this study was to test the effects of HSL infusion on brain and cardiac injury in an experimental model of CA.

METHODS

After a 10-min electrically induced CA followed by 5 min of cardiopulmonary resuscitation maneuvers, adult swine (n = 35) were randomly assigned to receive either balanced crystalloid (controls, n = 11) or HSL infusion started during cardiopulmonary resuscitation (CPR, Intra-arrest, n = 12) or after return of spontaneous circulation (Post-ROSC, n = 11) for the subsequent 12 h. In all animals, extensive multimodal neurological and cardiovascular monitoring was implemented. All animals were treated with targeted temperature management at 34 °C.

RESULTS

Thirty-four of the 35 (97.1%) animals achieved ROSC; one animal in the Intra-arrest group died before completing the observation period. Arterial pH, lactate and sodium concentrations, and plasma osmolarity were higher in HSL-treated animals than in controls (p < 0.001), whereas potassium concentrations were lower (p = 0.004). Intra-arrest and Post-ROSC HSL infusion improved hemodynamic status compared to controls, as shown by reduced vasopressor requirements to maintain a mean arterial pressure target > 65 mmHg (p = 0.005 for interaction; p = 0.01 for groups). Moreover, plasma troponin I and glial fibrillary acid protein (GFAP) concentrations were lower in HSL-treated groups at several time-points than in controls.

CONCLUSIONS

In this experimental CA model, HSL infusion was associated with reduced vasopressor requirements and decreased plasma concentrations of measured biomarkers of cardiac and cerebral injury.