IIT Study Reveals Covid-19 May Cause Loss of Smell & Taste by Affecting the Central Nervous System

Indian Institute of Technology (IIT), Jodhpur Scientists has explored the neuro-invasive nature of the Covid 19 virus. It highlights that loss of smell and taste of infected patients makes their entire Central Nervous System (CNS) & the underlying structures in the brain more prone to viral infection with devastating effects.

Dr. Surajit Ghosh with his team have pointed out that SARS-CoV-2 is known to interact with a specific human receptor known as hACE2 (human angiotensin-converting enzyme-2). It also happens to be the entry point of the virus and has an almost ubiquitous presence in most human organs ranging from lung parenchyma to nasal mucosa. The brain is also called to express this receptor.

The scientists have attributed the loss of smell or taste to the fact that nose & mouth both are very important entry points of the virus, which is likely that it may slowly be making its way to the olfactory bulb by using the neurons of the olfactory mucosa. The olfactory bulb is located in the forebrain which is the structure that is chiefly responsible for the sense of smell. Thus, it explains the loss of smell associated with many asymptomatic carriers of COVID-19 and also may be exposing the CNS to viral infection.

The paper accepted in ACS Chemical Neuroscience & supported by Science & Engineering Research Board (SERB), a Statutory Body of the Department of Science & Technology (DST), has suggested probable therapeutic strategies that can be adopted to combat it on the basis of understanding the neurological manifestations of the Covid-19.

The paper also recounts a newly conducted study on the brain scans (CT and MRI) of a patient infected by Covid-19 virus that shows a rare encephalopathy called ANE, which leads to brain dysfunction with seizures & mental disorientation. The study indicates that in the presence of human ACE2 receptors in CNS, the brain may be infected by the virus by the olfactory bulbs and also through other peripheral nerve terminals or simply blood circulation and may breach the blood-brain barrier to innervate & attack CNS. According to the scientists, it may also completely destroy the medulla oblongata of the hindbrain, which regulates breathing, heart, and blood vessel function.

The paper also give warnings to the asymptomatic carriers of Covid-19 with anosmia (loss of smell) and ageusia (loss of taste) to self-quarantine themselves as soon as they are feeling these and consult specialized nephrologists before they turn into carriers. It also suggests brain autopsies of Covid-19 infected patients & analysis of their cerebrospinal fluid.

According to Professor Ashutosh Sharma, Secretary, DST, "The pathway of infection of SARS-CoV-2 and its impact on various organs is an important area that will also help with the future rational approaches for therapy. The neuro-invasive nature of the virus & its effects on the senses of smell and taste are hence interesting & useful areas of investigation," said.

The publication also highlights that activities such as smoking could increase the chances of contracting Covid-19 infection. Thus, attributing it to the interactions and co-expression of the hACE2 receptor and the nicotinic receptor, that is stimulated on smoking.

Adding to it, the paper also reflects upon therapeutics agents ranging from the peptide-based therapeutics, which will curb the interaction between the viral protein & the human receptor to the strategic design of small molecule inhibitors designed against the viral spike protein that interacts with the ACE2. It suggests the development of subunit vaccines from the purified virus along with antibody-based drug.

For more details, you can contact Prof Surajit Ghosh

Email- sghosh@iitj.ac.in

Mob- +91-9903099747

Source: PIB