Nordic Life Science 1
82 “COVID affects our sense of smell when the vir
us enters the nasal cavity and destroys supporting cells of the mucosa. These support cells provide nutrients for olfactory sensory neurons, so without them, disruptions occur.” THOMAS HUMMEL L OSS OF THESE BASIC SENSES IS NOT JUST unpleasant, it disrupts individuals' and families’ lives and takes a toll on overall well-being, often leading to weight loss and depression. While people have always experienced loss of taste and/or smell due to illness or injury, the COVID-19 pandemic exploded the numbers of sufferers. Losing these senses is one of the earliest symptoms of COVID and usually people recover them within a few days or weeks. But for some people, it takes months to smell or taste again, for others, it can take years, and some people never do. Long COVID Prolonged loss of taste and smell is one of the indicators of Long COVID, a condition with a myriad of symptoms that researchers have been trying to isolate and treat. About 400 million people worldwide are struggling with symptoms of Long COVID, which besides loss of taste and smell, include “brain fog,” fatigue, heart and lung damage, insomnia, and depression. A huge part of the puzzle, which has delayed treatments for many of the conditions is figuring out why some people quickly recover quickly while others never do. But there are new insights into what causes the internal communication involving taste and smell to break down, which could lead to treatments and efforts to restore function using innovative technology. The European Union funded a multidisciplinary team of scientists to develop an olfactory prosthesis, and several prototypes have been tested. Referred to as the ROSE (Restoring Odorant detection and recognition in Smell dEficits) Project, the work involves using an implant to reconnect nerves involved with smell to the brain, in a similar way to how cochlear implants restore hearing for some people. A sensor placed in the nasal cavity would connect to the olfactory bulb with a series of wires, causing a pattern of activation. The signal is transferred to the brain, which translates the signal as an odor. Smell training Thomas Hummel, MD, a researcher at the Smell and Taste Clinic at the Technical University of Dresden in Germany, has had some success with smell training. While about 95 percent of patients eventually recover their sense of smell after COVID, Hummel’s clinic is busy; he sees approximately 800-1,000 patients per year. He has developed a treatment whereby patients smell four strong odors, such as essential oils, twice a day for about 30 seconds at a time for at least four months. A study showed that between 30 and 50 percent of participants reported improved smell sensitivity after the regimen. COVID affects our sense of smell when the virus enters the nasal cavity and destroys supporting cells of the mucosa, Hummel explained. These support cells provide nutrients for olfactory sensory neurons, so without them, disruptions occur. Smell and taste are connected Loss of smell and taste are connected, and more is understood about the loss of smell. This is according to Dr. Thomas Finger, a professor of cell and developmental biology at the University of Colorado Anschutz in the US, who was involved with a recent study into taste. “In smell, the virus infects the supporting cells of the sense organ, and this provokes an anti-viral response in those cells as well as in the olfactory receptor neurons,” Finger says. “This anti-viral response turns off the mRNA that encodes the proteins underlying the receptor responses to odor, hence the sense of smell is lost. After a few days the virus is cleared, and the sensory cells turn back on the odor-response proteins leading to recovery.” 4 1w Sli yo Sample p Comp reage • One s • Stre fr n THE NOSE // SMELL AND TASTE