Marylane da Silva Viana1, Allysson Allan Farias1, Felipe Domingos de Sousa2, Annyta Fernandes Frota1, Michelle Verde Ramo Soares1, Fátima de Cássia Evangelista de Oliveira1, Maria Francilene Sousa Silva1,2, Caio Andrade de Oliveira1, Danielle Silveira Macedo1
The COVID-19 pandemic has evolved with high transmissibility and mortality. Since then, many convalescent individuals have reported persistent symptoms with adverse effects on the central nervous system, including headache, anxiety, \"brain fog\" (memory deficits and other cognitive impairments), and various neurological manifestations. This condition is known as post-acute sequelae of SARS-CoV-2 infection (PASC), or \"long COVID.\" Its etiology and underlying mechanisms remain under investigation, given the increasing prevalence and multisystemic nature of the condition, which now encompasses more than 60 described symptoms.
The consequences of long COVID in pregnant women and its impact on child neurodevelopment remain uncertain. In this context, mass spectrometry emerges as a powerful tool for identifying biomarkers with diagnostic and therapeutic potential, positioning itself as a key ally in precision medicine.
This study presents a temporal analysis of plasma samples from pregnant women infected with SARS-CoV-2, approximately 24 months after initial diagnosis. Participants underwent clinical and psychometric evaluation, with emphasis on global cognition at the end of the follow-up period. High-abundance plasma proteins were depleted using a specific affinity column, and samples were analyzed by mass spectrometry (Synapt XS HDMS 8k coupled to an Acquity UPLC M-Class liquid chromatograph). Data were processed in Progenesis QI for Proteomics, with statistical and functional analyses performed using OmicScope.
A total of 223 proteins were identified, of which 141 were differentially expressed. Stratified proteins between the two groups showed consistency across biological replicates, as evidenced by the PCA-biplot. Differentially expressed proteins were subjected to functional enrichment using the KEGG, WikiPathways, and Reactome databases, whose integration provided greater interpretative robustness.
Among the 30 most recurrent proteins in the highlighted functional groups, 17 appeared simultaneously in all three databases, suggesting biological relevance. The identified proteins are components of the complement system and coagulation cascade: C1S, C2, C4BPA, C5, C6, C8A, C8G, C9, CFB, CFH, CFHR2, CFI, CPB2, F2, SERPING1, and VTN.
The complement system plays roles in pathogen recognition, inflammation amplification, opsonization, and formation of the membrane attack complex. In COVID-19, morbidity has been associated with an exacerbated immune response that may intensify microglial activation in the hippocampus. Due to its self-amplifying nature, small amounts of residual complement proteins can sustain inflammatory signaling. Proteins from the coagulation cascade found here have important roles in tissue hypoxia, contributing to the formation of amyloid fibrin microclots, which have been associated with long COVID in several tissues, including the brain.
Twenty-four months after infection, participants were assessed using the Addenbrooke’s Cognitive Examination (ACE). The mean total score was 78.6, indicating potential cognitive impairment according to normative values for the Brazilian population. This study demonstrates that proteomic signatures of immune activation and coagulopathy persist over time and correlate with the cognitive impairment observed in mothers, as well as the negative impact on child development still under observation.
Agradecimentos: We gratefully acknowledge the National Council for Scientific and Technological Development (CNPq) for the doctoral scholarship, and the Federal University of Ceará (UFC) and the University of Fortaleza (UNIFOR) for institutional support and research infrastructure.