PBC Complex

SERB-supported study shows that collapse of the respiratory center in the brain may cause the breakdown of COVID-19 patients

• The team of researchers at CSIR-Indian Institute of Chemical Biology (IICB), Kolkata has explored the neuro-invasive potential of SARS-CoV-2 and suggested that the virus may infect respiratory centre of the brain and attention should be focused on the respiratory centre of the central nervous system to search for mortality due to COVID 19.
• The paper published in ACS Chemical Neuroscience and supported by the Science & Engineering Research Board (SERB), a Statutory Body of the Department of Science & Technology (DST), implies that the SARS-CoV-2 virus might enter the human brain through the nose and reaches the olfactory bulb of the brain.
• From there, the SARS-CoV-2 virus might infect the PreBötzinger complex (PBC), the primary centre of the brain that controls respiratory rhythm generation.
• This explains that the collapse of the respiratory centre in the brain may be responsible for the breakdown of COVID-19 patients.
• Although, the lung is one of the most infected organs, several other organs, including the brain, are also affected.
• This is the first report that highlights that SARS-CoV-2 may target the PBC of the brainstem that controls respiration and causes respiratory collapse of COVID-19 patients.
• The scientists have suggested that cerebrospinal fluid of COVID-19 patients and postmortem brain of deceased patients should be assessed to better understand the route of SARS-CoV-2 entry and its spread to respiratory center of brain.

PreBötzinger complex

• PreBötzinger complex functions as the primary respiratory oscillator and it has been proposed as a centre of respiration.
• It has been earlier shown that disruption of PBC causes lethality due to respiratory failure, suggesting its central role in respiratory rhythm generation.
• It is possible that SARS-CoV-2 may shut down the respiratory centre, and in turn, breathe by infecting and destroying the PBC of the brainstem.
• Although this underline hypothesis needs to be validated for SARS-CoV-2, another recent study from a group of scientists at King’s College London, UK highlighted the loss of smell was one of the main symptoms of COVID-19 patients, hinting at the involvement of the same route through which SARS-CoV-2 may enter the brain.
• SARS-CoV-2 and SARS-CoV not only share high levels of DNA sequence similarity, but both of them also exploit the same angiotensin-converting enzyme 2 (ACE2) receptor, through which the virus enters in target cells.
• Due to this, it was anticipated that the mechanism through which SARS-CoV infected the host cell could also be the same for SARS-CoV-2.

Way ahead

• The study highlights that it is important to not only screen the COVID-19 patients for neurological symptoms but also further segregate when the symptom appears.
• The researchers have pointed out that while at present, the brain is not considered the site of the primary or secondary reason for the death of COVID-19, attention needs to be focused on the respiratory centre of the CNS.
• Postmortem the brain of COVID-19 patients could be assessed to know the route of entry and affected areas including a detailed assessment of the respiratory centre of the brain.