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.

Alterations in the metabolism of Pseudosuccinea columella (Mollusca: Gastropoda) caused by Heterorhabditis bacteriophora HP88 (Rhabditida: Heterorhabditidae)

The gastropod Pseudosuccinea columella participates in the dissemination of Fasciola hepatica in the environment, acting as the main intermediate host of this parasite in Brazil. The present study sought to elucidate the possible pathogenic effects of the entomopathogenic nematode (EPN) Heterorhabditis bacteriophora on P. columella, by evaluating the influence of infection on alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as the concentrations of total protein, uric acid, and urea in the snail's hemolymph. For this, the snails were exposed to EPNs for 24 and 48 h, and for each exposure time, 20 snails were dissected after 7, 14 and 21 days for hemolymph collection. The primary findings suggest a significant proteolysis alongside elevated levels of uric acid and urea in P. columella infected individuals. These findings reveal that H. bacteriophora HP88 infection induced serious changes in the snail's metabolism, triggering important deleterious effects.

Influence of exposure Heterorhabditis bacteriophora HP88, (Rhabditida: Heterorhabditidae) on biological and physiological parameters of Pseudosuccinea columella (Basommatophora: Lymnaeidae)

Many studies about fasciolosis control have been carried out, whether acting on the adult parasite or in Pseudosuccinea columella, compromising the development of the larval stages. The present study aimed to evaluate, under laboratory conditions, the susceptibility of P. columella to Heterorhabditis bacteriophora HP88, during for 24 and 48 hours of exposure. The snails were evaluated for 21 days for accumulated mortality; number of eggs laid; hatchability rate; biochemical changes; and histopathological analysis. We found that exposure induced a reduction in glucose and glycogen levels, characterizing a negative energy balance, due to the depletion of energy reserves as a result of the direct competition established by the nematode/endosymbiont bacteria complex in such substrates. A mortality rate of 48.25% and 65.52% was observed in the group exposed for 24 h and 48 h, respectively, along with significant impairment of reproductive biology in both exposed groups in relation to the respective controls. The results presented here show that P. columella is susceptible to the nematode H. bacteriophora, with the potential to be used as an alternative bioagent in the control of this mollusk, especially in areas considered endemic for fascioliasis, in line with the position expressed by the World Health Organization Health.

Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae), isolate HP88, induces reproductive and physiological alterations in Biomphalaria glabrata (Gastropoda: Planorbidae): an alternative for biological control of schistosomiasis

Heterorhabditis bacteriophora is an entomopathogenic nematode (EPN) that is mutually associated with Photorhabdus luminescens, utilized globally for biological control of numerous organisms. Freshwater snails of the species Biomphalaria glabrata have been incriminated as the main intermediate hosts of Schistosoma mansoni in Brazil, but virtually nothing is known about the susceptibility of these gastropod to EPNs. Information in this respect is relevant for control of these intermediate hosts, and thus of the helminthiases they transmit. This paper for the first time reports the susceptibility of B. glabrata to infective juveniles of H. bacteriophora (isolate HP88) under laboratory conditions. For that purpose, six groups were formed: three Control groups (not exposed) and three Treated groups, in which the snails were exposed to 300 juveniles infecting the nematode over three weeks. The entire experiment was conducted in triplicate, using a total of 270 snails. Significant physiological alterations in B. glabrata were observed in response to the infection by H. bacteriophora HP88, characterized by decreased levels of hemolymphatic glucose as well as reduced contents of glycogen stored in the host's digestive gland. In parallel, the hemolymphatic activity of lactate dehydrogenase increased in the infected snails, indicating that the infection induces breakdown of carbohydrate homeostasis in B. glabrata. Additionally, all the reproductive parameters analyzed were reduced as a consequence of the infection. The results indicate the occurrence of the phenomenon of parasitic castration in the B. glabrata/H. bacteriophora HP88 interface, probably due to the depletion of galactogen in the parasitized organism. Although the infection did not cause lethality in the population of infected snails, H. bacteriophora HP88 compromised the reproductive performance of B. glabrata, suggesting its applicability in programs for biological control of this planorbid.

Biosynthesis and mass spectral fragmentation pathways of (13)C and (15)N labeled cytochalasin D produced by Xylaria arbuscula

The fungus Xylaria arbuscula was isolated as an endophyte from Cupressus lusitanica and has shown to be a prominent producer of cytochalasins, mainly cytochalasins C, D and Q. Cytochalasins comprise an important class of fungal secondary metabolites that have aroused attention due to their uncommon molecular structures and pronounced biological activities. Due to the few published studies on the ESI-MS/MS fragmentation of this important class of secondary metabolites, in the first part of our work, we studied the cytochalasin D fragmentation pathways by using an ESI-Q-ToF mass spectrometer coupled with liquid chromatography. We verified that the main fragmentation routes were generated by hydrogen and McLafferty rearrangements which provided more ions than just the ones related to the losses of H₂ O and CO as reported in previous studies. We also confirmed the diagnostic ions at m/z 146 and 120 as direct precursor derived from phenylalanine. The present work also aimed the production of structurally diverse cytochalasins by varying the culture conditions used to grow the fungus X. arbuscula and further insights into the biosynthesis of cytochalasins. HPLC-MS analysis revealed no significant changes in the metabolic profile of the microorganism with the supplementation of different nitrogen sources but indicated the ability of X. arbuscula to have access to inorganic and organic nitrogen, such as nitrate, ammonium and amino acids as a primary source of nitrogen. The administration of 2-¹³ C-glycine showed the direct correlation of this amino acid catabolism and the biosynthesis of cytochalasin D by X. arbuscula, due to the incorporation of three labeled carbons in cytochalasin chemical structure. Copyright © 2017 John Wiley & Sons, Ltd.

Method validation of nanoparticle tracking analysis to measure pulmonary nanoparticle content: the size distribution in exhaled breath condensate depends on occupational exposure

A particle exposure assessment based on the dose deposited in the lungs would be the gold standard for the evaluation of any resulting health effects. Measuring particles in exhaled breath condensate (EBC)-a matrix containing water and airway lining fluid-could help to evaluate particle retention in the lungs. This study aimed to (1) validate a nanoparticle tracking analysis (NTA) method for determining the particle number concentration and their hydrodynamic size distribution in EBC, and (2) apply this method to EBC collected from workers exposed to soapstone (n = 55) or quartz dust (n = 12) and controls (n = 11). A standard latex bead solution was used to determine the linear range, limit of detection (LOD), repeatability (coefficient of variation, CV), and bias in spiked EBC. An LM10 NanoSight instrument with NTA version 3.1 software was used for measurement. RTubes^® were used for field collection of EBC. The repeatability obtained for a D₅₀ size distribution in EBC showed less than 8% variability, with a bias <7%. The particle concentration was linear in the range ≤2.5 × 10⁸ particles ml^-1 with a LOD of 4 × 10⁶ particles ml^-1. A recovery of 117 ± 20% at 6.2 × 10⁷ particles ml^-1 was obtained with a CV <10% and a bias <20%. EBC from workers exposed to quartz, who experienced the largest exposure to silica particles, consistently exhibited a statistically significant (p < 0.01) higher concentration of particles in their EBC, with a size distribution shift towards larger values than the other groups. Results showed that the NTA technique performed well for characterizing the size distribution and concentrations of particles in EBC. The technique needs to be corroborated with a larger population of workers.

Biochemical profile of Achatina fulica (Mollusca: Gastropoda) after infection by different parasitic loads of Angiostrongylus cantonensis (Nematoda, Metastrongylidae)

The effect of experimental infection by different parasitic loads of Angiostrongylus cantonensis (Nematode, Metastrongylidae) on the activities of the aminotransferases and concentration of total proteins, uric acid and urea in the hemolymph of Achatina fulica (Mollusca, Gastropoda) were investigated. There was a significant decrease in the concentration of total proteins in the exposed snails to 5000 or more larvae. This change was accompanied by an increase in the concentrations of urea and uric acid in the hemolymph, suggesting a higher rate of deamination of the amino acids. Besides this, variations in the activities of the aminotransferases were also observed, with the highest values recorded in the groups exposed to greater parasite load. These results suggest an increase in the use of total proteins, since there was increased formation of nitrogenous catabolites, in conformity with an increase in the aminotransferase activities. Infection was verified by the fact that L3 larvae recovered from the snails was proportion to the exposure dose of L1 larvae. Histopathological results also indicated presence of an inflammatory cell infiltrate, favoring an increase of both transaminases.

Metformin inhibits inflammatory angiogenesis in a murine sponge model

To investigate the effects of metformin on angiogenesis, on inflammatory cell accumulation and on production of endogenous cytokines in sponge implant in mice. Polyester-polyurethane sponges were implanted in Swiss mice and metformin (40 or 400mg/kg/day) was given orally for six days. The implants collected at day 7 postimplantation were processed for the assessment of hemoglobin (Hb), myeloperoxidase (MPO), N-acetylglucosaminidase (NAG) e collagen used as indexes for angiogenesis, neutrophil and macrophage accumulation and extracellular matrix deposition, respectively. Relevant inflammatory, angiogenic and fibrogenic cytokines were also determined. Metformin treatment attenuated the main components of the fibrovascular tissue, wet weight, vascularization (Hb content), macrophage recruitment (NAG activity), collagen deposition and the levels of transforming growth factor (TGF-beta1) intraimplant. A regulatory function of metformin on multiple parameters of main components of inflammatory angiogenesis has been revealed giving insight into the potential therapeutic underlying the actions of metformin.