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Vagus nerve dysfunction in the post–COVID-19 condition: a pilot cross-sectional study

Authors: Gemma Lladós, Marta Massanella, Roser Coll-Fernández, Raúl Rodríguez, Electra Hernández, Giuseppe Lucente, Cristina López, Cora Loste, José Ramón Santos, Sergio España-Cueto, Maria Nevot, Francisco Muñoz-López, Sandra Silva-Arrieta, Christian Brander, Maria José Durà, Patricia Cuadras, Jordi Bechini, Montserrat Tenesa, Alicia Martinez-Piñeiro, Cristina Herrero, Anna Chamorro, Anna Garcia, Eulalia Grau, Bonaventura Clotet, Roger Paredes, Lourdes Mateu, on behalf of theGermans Trias Long-COVID Unit group


Objectives. The post–COVID-19 condition (PCC) is a disabling syndrome affecting at least 5%–10% of subjects who survive COVID-19. SARS-CoV-2 mediated vagus nerve dysfunction could explain some PCC symptoms, such as dysphonia, dysphagia, dyspnea, dizziness, tachycardia, orthostatic hypotension, gastrointestinal disturbances, or neurocognitive complaints.

Methods. We performed a cross-sectional pilot study in subjects with PCC with symptoms suggesting vagus nerve dysfunction (n = 30) and compared them with subjects fully recovered from acute COVID-19 (n = 14) and with individuals never infected (n = 16). We evaluated the structure and function of the vagus nerve and respiratory muscles.

Results. Participants were mostly women (24 of 30, 80%), and the median age was 44 years (interquartile range [IQR] 35–51 years). Their most prevalent symptoms were cognitive dysfunction 25 of 30 (83%), dyspnea 24 of 30 (80%), and tachycardia 24 of 30 (80%). Compared with COVID-19-recovered and uninfected controls, respectively, subjects with PCC were more likely to show thickening and hyperechogenic vagus nerve in neck ultrasounds (cross-sectional area [CSA] [mean ± standard deviation]: 2.4 ± 0.97mm2 vs. 2 ± 0.52mm2 vs. 1.9 ± 0.73 mm2; p 0.08), reduced esophageal-gastric-intestinal peristalsis (34% vs. 0% vs. 21%; p 0.02), gastroesophageal reflux (34% vs. 19% vs. 7%; p 0.13), and hiatal hernia (25% vs. 0% vs. 7%; p 0.05). Subjects with PCC showed flattening hemidiaphragms (47% vs. 6% vs. 14%; p 0.007), and reductions in maximum inspiratory pressure (62% vs. 6% vs. 17%; p ≤ 0.001), indicating respiratory muscle weakness. The latter findings suggest additional involvement of the phrenic nerve.

Discussion. Vagus and phrenic nerve dysfunction contribute to the complex and multifactorial pathophysiology of PCC.

Journal: Clinical Microbiology and Infection

Date: 2023 April 24

Animal models to study the neurological manifestations of the post-COVID-19 condition

Authors: Carla Usai, Lourdes Mateu, Christian Brander, Júlia Vergara-Alert and Joaquim Segalés.


More than 40% of individuals infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have experienced persistent or relapsing multi-systemic symptoms months after the onset of coronavirus disease 2019 (COVID-19). This post-COVID-19 condition (PCC) has debilitating effects on the daily life of patients and encompasses a broad spectrum of neurological and neuropsychiatric symptoms including olfactory and gustative impairment, difficulty with concentration and short-term memory, sleep disorders and depression. Animal models have been instrumental to understand acute COVID-19 and validate prophylactic and therapeutic interventions. Similarly, studies post-viral clearance in hamsters, mice and nonhuman primates inoculated with SARS-CoV-2 have been useful to unveil some of the aspects of PCC. Transcriptomic alterations in the central nervous system, persistent activation of immune cells and impaired hippocampal neurogenesis seem to have a critical role in the neurological manifestations observed in animal models infected with SARS-CoV-2. Interestingly, the proinflammatory transcriptomic profile observed in the central nervous system of SARS-CoV-2-inoculated mice partially overlaps with the pathological changes that affect microglia in humans during Alzheimer’s disease and aging, suggesting shared mechanisms between these conditions. None of the currently available animal models fully replicates PCC in humans; therefore, multiple models, together with the fine-tuning of experimental conditions, will probably be needed to understand the mechanisms of PCC neurological symptoms. Moreover, given that the intrinsic characteristics of the new variants of concern and the immunological status of individuals might influence PCC manifestations, more studies are needed to explore the role of these factors and their combinations in PCC, adding further complexity to the design of experimental models.

Journal: labanimal, Nature

Date: 2023 August 24

Plasma proteomic profiling identifies CD33 as a marker of HIV control in natural infection and after therapeutic vaccination

Authors: Clara Duran-Castells, Anna Prats, Bruna Oriol-Tordera, Anuska Llano, Cristina Galvez, Javier Martinez-Picado, Ester Ballana, Edurne Garcia-Vidal, Bonaventura Clotet, Jose A Muñoz-Moreno, Thomas Hanke, José Moltó, Beatriz Mothe, Christian Brander, Marta Ruiz-Riol.


Background: Biomarkers predicting the outcome of HIV-1 virus control in natural infection and after therapeutic interventions in HIV-1 cure trials remain poorly defined. The BCN02 trial (NCT02616874), combined a T-cell vaccine with romidepsin (RMD), a cancer-drug that was used to promote HIV-1 latency reversal and which has also been shown to have beneficial effects on neurofunction. We conducted longitudinal plasma proteomics analyses in trial participants to define biomarkers associated with virus control during monitored antiretroviral pause (MAP) and to identify novel therapeutic targets that can improve future cure strategies.

Methods: BCN02 was a phase I, open-label, single-arm clinical trial in early-treated, HIV infected individuals. Longitudinal plasma proteomes were analyzed in 11 BCN02 participants, including 8 participants that showed a rapid HIV-1 plasma rebound during a monitored antiretroviral pause (MAP-NC, ‘non-controllers’) and 3 that remained off ART with sustained plasma viremia <2000 copies/ml (MAP-C, ‘controllers’). Inflammatory and neurological proteomes in plasma were evaluated and integration data analysis (viral and neurocognitive parameters) was performed. Validation studies were conducted in a cohort of untreated HIV-1+ individuals (n = 96) and in vitro viral replication assays using an anti-CD33 antibody were used for functional validation.

Findings: Inflammatory plasma proteomes in BCN02 participants showed marked longitudinal alterations. Strong proteome differences were also observed between MAP-C and MAP-NC, including in baseline timepoints. CD33/Siglec-3 was the unique plasma marker with the ability to discriminate between MAPC-C and MAP-NC at all study timepoints and showed positive correlations with viral parameters. Analyses in an untreated cohort of PLWH confirmed the positive correlation between viral parameters and CD33 plasma levels, as well as PBMC gene expression. Finally, adding an anti-CD33 antibody to in vitro virus cultures significantly reduced HIV-1 replication and proviral levels in T cells and macrophages.

Journal: eBioMedicine

Date: 2023 July 26

Sirtuin-2, NAD-Dependent Deacetylase, Is a New Potential Therapeutic Target for HIV-1 Infection and HIV-Related Neurological Dysfunction

Authors: Clara Duran-Castells, Anuska Llano, Ai Kawana-Tachikawa, Anna Prats, Ignacio Martinez-Zalacain,  Mie Kobayashi-Ishihara, Bruna Oriol-Tordera, Ruth Peña, Cristina Gálvez, Sandra Silva-Arrieta, Bonaventura Clotet, Eva Riveira-Muñoz, Esther Ballana, Julia G. Prado, Javier Martinez-Picado, Jorge Sanchez, Beatriz Mothe, Dennis Hartigan-O’Connor, Tony Wyss-Coray, Andreas Meyerhans, Magnus Gisslén, Richard W. Price, Carles Soriano-Mas, José Antonio Muñoz-Moreno, Christian Brander, and Marta Ruiz-Riol.


The implementation and access to combined antiretroviral treatment (cART) have dramatically improved the quality of life of people living with HIV (PLWH). However, some comorbidities, such as neurological disorders associated with HIV infection still represent a serious clinical challenge. Soluble factors in plasma that are associated with control of HIV replication and neurological dysfunction could serve as early biomarkers and as new therapeutic targets for this comorbidity. We used a customized antibody array for determination of blood plasma factors in 40 untreated PLWH with different levels of viremia and found sirtuin-2 (SIRT2), an NAD-dependent deacetylase, to be strongly associated with elevated viral loads and HIV provirus levels, as well as with markers of neurological damage (a-synuclein [SNCA], brain-derived neurotrophic factor [BDNF], microtubule-associated protein tau [MAPT], and neurofilament light protein [NFL]). Also, longitudinal analysis in HIV-infected individuals with immediate (n = 9) or delayed initiation (n = 10) of cART revealed that after 1 year on cART, SIRT2 plasma levels differed between both groups and correlated inversely with brain orbitofrontal cortex involution. Furthermore, targeting SIRT2 with specific small-molecule inhibitors in in vitro systems using J-LAT A2 and primary glial cells led to diminished HIV replication and virus reactivation from latency. Our data thus identify SIRT2 as a novel biomarker of uncontrolled HIV infection, with potential impact on neurological dysfunction and offers a new therapeutic target for HIV treatment and cure.

Journal: Journal of Virology

Date: 2023 January 31