Persistent cognitive impairment associated with cerebrospinal fluid anti-SARS-CoV-2 antibodies six months after mild COVID-19

Acute and long-term effects of COVID-19 on brain and mental health: A narrative review

BACKGROUND

COVID infection has been associated with long term sequalae (Long COVID) which include neurological and behavioral effects in thousands of patients, but the etiology and scope of symptoms is not well understood. This paper reviews long term sequelae of COVID on brain and mental health in patients with the Long COVID syndrome.

METHODS

This was a literature review which queried databases for Pubmed, Psychinfo, and Medline for the following topics for January 1, 2020-July 15, 2023: Long COVID, PASC, brain, brain imaging, neurological, neurobiology, mental health, anxiety, depression.

RESULTS

Tens of thousands of patients have developed Long COVID, with the most common neurobehavioral symptoms anosmia (loss of smell) and fatigue. Anxiety and mood disorders are elevated and seen in about 25% of Long COVID patients. Neuropsychological testing studies show a correlation between symptom severity and cognitive dysfunction, while brain imaging studies show global decreases in gray matter and alterations in olfactory and other brain areas.

CONCLUSIONS

Studies to date show an increase in neurobehavioral disturbances in patients with Long COVID. Future research is needed to determine mechanisms.

Impact of COVID-19 on Anxiety and Depression - Biopsychosocial Factors

Anxiety and depression are prevalent mental disorders around the world. The etiology of both diseases is multifactorial, involving biological and psychological issues. The COVID-19 pandemic settled in 2020 and culminated in several changes in the routine of individuals around the world, affecting mental health. People infected with COVID-19 are at greater risk of developing anxiety and depression, and individuals previously affected by these disorders have worsened the condition. In addition, individuals diagnosed with anxiety or depression before being affected by COVID-19 developed the severe illness at higher rates than individuals without mental disorders. This harmful cycle involves several mechanisms, including systemic hyper-inflammation and neuroinflammation. Furthermore, the context of the pandemic and some previous psychosocial factors can aggravate or trigger anxiety and depression. Disorders are also risks for a more severe picture of COVID-19. This review discusses research on a scientific basis, which brings evidence on biopsychosocial factors from COVID-19 and the context of the pandemic involved in anxiety and depression disorders.

The kynurenine pathway of tryptophan metabolism: a neglected therapeutic target of COVID-19 pathophysiology and immunotherapy

SARS-CoV-2 (COVID-19) exerts profound changes in the kynurenine (Kyn) pathway (KP) of tryptophan (Trp) metabolism that may underpin its pathophysiology. The KP is the main source of the vital cellular effector NAD+ and intermediate metabolites that modulate immune and neuronal functions. Trp metabolism is the top pathway influenced by COVID-19. Sixteen studies established virus-induced activation of the KP mediated mainly by induction of indoleamine 2,3-dioxygenase (IDO1) in most affected tissues and of IDO2 in lung by the increased release of proinflammatory cytokines but could additionally involve increased flux of plasma free Trp and induction of Trp 2,3-dioxygenase (TDO) by cortisol. The major Kyn metabolite targeted by COVID-19 is kynurenic acid (KA), the Kyn metabolite with the greatest affinity for the aryl hydrocarbon receptor (AhR), which is also activated by COVID-19. AhR activation initiates two important series of events: a vicious circle involving IDO1 induction, KA accumulation and further AhR activation, and activation of poly (ADP-ribose) polymerase (PARP) leading to NAD+ depletion and cell death. The virus further deprives the host of NAD+ by inhibiting its main biosynthetic pathway from quinolinic acid, while simultaneously acquiring NAD+ by promoting its synthesis from nicotinamide in the salvage pathway. Additionally, the protective effects of sirtuin 1 are minimised by the PARP activation. KP dysfunction may also underpin the mood and neurological disorders acutely and during 'long COVID'. More studies of potential effects of vaccination therapy on the KP are required and exploration of therapeutic strategies involving modulation of the KP changes are proposed.

Symptom Burden and Immune Dynamics 6 to 18 Months Following Mild Severe Acute Respiratory Syndrome Coronavirus 2 Infection (SARS-CoV-2): A Case-control Study

BACKGROUND

The burden and duration of persistent symptoms after nonsevere coronavirus disease 2019 (COVID-19) remains uncertain. This study aimed to assess postinfection symptom trajectories in home-isolated COVID-19 cases compared with age- and time- matched seronegative controls, and investigate immunological correlates of long COVID.

METHODS

A prospective case-control study included home-isolated COVID-19 cases between February 28 and April 4, 2020, and followed for 12 (n = 233) to 18 (n = 149) months, and 189 age-matched severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-naive controls. We collected clinical data at baseline, 6, 12, and 18 months postinfection, and blood samples at 2, 4, 6, and 12 months for analysis of SARS-CoV-2-specific humoral and cellular responses.

RESULTS

Overall, 46% (108/233) had persisting symptoms 12 months after COVID-19. Compared with controls, adult cases had a high risk of fatigue (27% excess risk, sex, and comorbidity adjusted odds ratio [aOR] 5.86; 95% confidence interval [CI], 3.27-10.5), memory problems (21% excess risk; aOR 7.42; CI, 3.51-15.67), concentration problems (20% excess risk; aOR 8.88; 95% CI, 3.88-20.35), and dyspnea (10% excess risk; aOR 2.66; 95% CI, 1.22-5.79). The prevalence of memory problems increased overall from 6 to 18 months (excess risk 11.5%; 95% CI, 1.5-21.5; P = .024) and among women (excess risk 18.7%; 95% CI, 4.4-32.9; P = .010). Longitudinal spike immunoglobulin G was significantly associated with dyspnea at 12 months. The spike-specific clonal CD4+ T-cell receptor β depth was significantly associated with both dyspnea and number of symptoms at 12 months.

CONCLUSIONS

This study documents a high burden of persisting symptoms after mild COVID-19 and suggests that infection induced SARS-CoV-2-specific immune responses may influence long-term symptoms.

Association between serologically confirmed COVID-19 infection and cognitive functioning in community dwelling older adults

Introduction

COVID-19 infection can impact the central nervous system, and is often associated with cognitive decline. However, there are no studies linking serologically confirmed COVID-19 infection with objectively assessed cognitive functioning. We explored whether presence of SARS-CoV-2 antibodies account for variability in participants' scores on a neuropsychological assessment.

Methods

In this cross-sectional study participants were 657 (mean age = 72.97; SD = 6.07 years; women = 47.7%) individuals randomly selected from the general population of the canton of Zurich and included in the Corona Immunitas study. We conducted serological tests between October 2020 and May 2021 to detect and quantify SARS-CoV-2 antibodies in peripheral venous blood samples. We assessed cognitive function, vaccination status (vaccinated; not vaccinated), number of health conditions, and demographic variables between January and August 2021. We studied the association between seropositivity and global cognitive function and five cognitive domains (language expression, language comprehension, temporal orientation, spatial orientation, and memory) with linear regression models. Based on SARS-CoV-2 antibodies and vaccination status, we stratified participants into three groups: No SARS-CoV-2 antibodies (N = 402); SARS-CoV-2 antibodies due to vaccination (N = 218); history of SARS-CoV-2 infection and no vaccination (N = 37).

Results

In the regression model adjusted for age, sex, educational level, and number of health conditions, compared to those without SARS-CoV-2 antibodies, those with SARS-CoV-2 antibodies due to vaccination had better global cognitive functioning (Standardized beta = 0.10; 95% CI = 0.02; 0.17), and those with SARS-CoV-2 antibodies due to infection had poorer cognitive functioning (Standardized beta = -0.10; 95% CI = -0.18; -0.03). Regarding cognitive domains, compared to those without SARS-CoV-2 antibodies, those with SARS-CoV-2 antibodies due to infection scored more poorly on language comprehension and temporal orientation, and those with SARS-CoV-2 antibodies due to vaccination scored better on memory.

Discussion

By linking serologically confirmed presence of SARS-CoV-2 antibodies to poorer global cognitive functioning in community dwelling older adults we strengthen existing evidence in support of cognitive decline related to COVID-19. Given the large number of infected older adults, and the endurance of the pandemic, our results highlight the need to address COVID-19 related cognitive decline in the clinical and public health areas of prevention, diagnosis, and treatment.

Troubles mnésiques persistants post-COVID-19 : intérêt de la recherche des anti-SARS-CoV-2 dans le LCR couplée à la spectro-IRM cérébrale ?

Introduction

La maladie post-COVID-19 se développe quelle que soit la gravité de l’infection à SARS-CoV-2 initiale et comporte un large éventail de manifestations cliniques parmi lesquelles figurent de nombreux troubles neurologiques tels que les céphalées, l’anosmie, des troubles de la mémoire….

Observation

Nous rapportons le cas d’une patiente âgée de 68 ans adressée en consultation de médecine interne pour asthénie, troubles de la concentration et de la mémoire dans les suites d’une infection à SARS-CoV-2. Ses antécédents sont marqués par une HTA, un asthme, une thrombose veineuse profonde, une cholécystectomie, un œdème de Quincke avec choc anaphylactique aux AINS et une hypogammaglobulinémie modérée. On note une absence d’intoxication alcoolo-tabagique. La patiente a présenté en janvier 2021 une infection à SARS-CoV-2 avec fièvre et céphalées. La recherche de virus par PCR était négative lors de cet épisode avec secondairement une sérologie positive confirmant l’infection. Progressivement sont apparus des troubles de la mémoire et de la concentration. Son MMS était à 27/30.

L’IRM cérébrale en juin 2021 montrait de multiples hypersignaux de la substance blanche.

Un bilan a été réalisé en hôpital de jour avec réalisation d’une ponction lombaire.

Le LCR retrouvait l’absence de leucocytes (< 1 élément/mm³), des hématies à 24 éléments/mm³ et une protéinorachie à 0,45 g/L.

Les anticorps anti-rNMDA, anti-CASPR2, anti-rGABAb, anti-DPPX, anti-LGI1 et anti-AMPAr dans le LCR étaient négatifs.

Absence de bande surnuméraire à l’isofocalisation.

Les anticorps anti-SARS-CoV-2 dans le LCR étaient positifs à 108,7 UA/mL, la recherche de virus par PCR étant négative.

Le rapport de Delpech était normal à 0,52 mais n’excluant pas une synthèse intrathécale d’IgG. Par ailleurs, l’index albumine LCR/albumine sérum était normal.

Une polysomnographie ne retrouvait pas de syndrome d’apnées du sommeil.

Une spectroscopie par IRM cérébrale en mai 2022 a mis en évidence une réaction gliale ainsi qu’une dysfonction neuronale au niveau de l’hippocampe et de la protubérance.

Discussion

Les séquelles neuropsychologiques post-COVID-19 témoignent d’une neuro-inflammation liée à l’activation de la microglie et à une réaction auto-immune [1]. La persistance de troubles cognitifs associée à la présence d’anticorps anti-SARS-CoV-2 dans le LCR 6 mois après COVID-19 a été rapportée chez une patiente de 57 ans [2]. Dans notre observation, la présence de ces anticorps peut témoigner d’une neuro-inflammation constatée sur la spectroscopie par IRM cérébrale. Une exploration biologique plus approfondie du LCR ainsi qu’une exploration par spectroscopie par IRM cérébrale pourraient être suggérées chez les patients présentant des troubles cognitifs plusieurs mois après une infection à SARS-CoV-2.

Conclusion

D’autres études seront nécessaires afin de mieux définir la place de la recherche des anticorps anti-SARS-CoV-2 dans le LCR chez les patients ayant des séquelles neurologiques majeures liées au COVID-19.