Neuroinvasion by Human Respiratory Coronaviruses

The study titled “Neuroinvasion by Human Respiratory Coronaviruses” explores the potential connection between human coronaviruses (HCoVs) and neurological diseases, particularly multiple sclerosis (MS).

Here’s a detailed summary:

Study Context and Objective

  • Background: Human coronaviruses, known for causing common colds, have also been identified in neural cell cultures. This study aimed to provide definitive evidence of the neurotropism and neuroinvasion of HCoV and its potential link to MS.
  • Methodology: Extensive search and characterization of HCoV RNA were conducted in a large panel of human brain autopsy samples using reverse transcription-PCR and Southern hybridization​​.

Key Findings

  1. Detection of HCoV in Brain Samples:
    • The study found HCoV RNA in 48% of donors, with a higher prevalence of OC43 strain in MS patients compared to controls.
    • 44% of donors were positive for 229E, and 23% were positive for OC43.
    • A statistically significant higher prevalence of OC43 was found in MS patients (35.9%) compared to controls (13.7%)​​.
  2. Association with Neurological Diseases:
    • Previous studies have linked HCoV with MS, suggesting these viruses might be neurotropic, neuroinvasive, and neurovirulent in humans, similar to their murine counterparts​​.
  3. HCoV Strains and MS:
    • The study did not find a preferential association of HCoV-229E with any specific diagnosis, but the OC43 strain was more prevalent in MS patient brain samples.
    • This indicates a possible connection between OC43 strain and MS, but further studies are needed to establish a clear link​​.
  4. Persistent Infection Hypothesis:
    • The detection of HCoV RNA in normal brain tissue suggests these viruses might establish persistent infections within the CNS.
    • This could be particularly relevant in MS patients where the damaged blood-brain barrier might facilitate viral access to the CNS​​.
  5. Potential Effects and Molecular Adaptation:
    • Some detected mutations in the OC43 strain were never observed in laboratory viruses, suggesting possible molecular adaptation to the human CNS.
    • The study proposes that HCoV-OC43 may adapt to the CNS environment and, in some cases, cause neurological abnormalities either directly or indirectly​​.

Conclusions

  • Implications: The presence of HCoV RNA in a significant proportion of human brain samples suggests a potential role in neurological diseases, including MS.
  • Future Research: Further investigation is needed to understand the potential pathological effects of HCoV persistence in the CNS and its relevance to MS and other neurological diseases.

Significance

This study contributes to the growing understanding of the complex interactions between respiratory viruses like HCoVs and the central nervous system. It opens up new avenues for exploring the role of these viruses in the etiology of neurological diseases and underscores the need for continued research in this area.

Read More: https://journals.asm.org/doi/epub/10.1128/jvi.74.19.8913-8921.2000

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