VCU Study: Steroid may help repair damage to sense of smell following head injury

By Sathya Achia Abraham

An international team of researchers has found that administration of the steroid dexamethasone following olfactory nerve injury minimizes the inflammatory response and allows for improved nerve regeneration and recovery, which may help repair damage to the sense of smell after a head injury.

Following injury, the olfactory system – responsible for sense of smell - has a limited capacity to regenerate and recover function. Inflammatory diseases such as severe sinusitis can cause damage or dysfunction of the olfactory system, but sometimes improves with the administration of antibiotics and topical sprays.

In contrast, recovery of olfactory nerve sensation following a head injury is relatively poor, so researchers are working to gain a better understanding of the mechanisms of injury and recovery in order to develop new treatments for those who suffer smell loss due to head trauma and olfactory nerve injury.

Richard M. Costanzo, Ph.D., professor of physiology and biophysics, otolaryngology, neurology and anatomy in the VCU School of Medicine, together with Masayoshi Kobayashi, M.D., Ph.D, with the Mie University Graduate School of Medicine in Japan, developed mouse models to compare differences in recovery outcomes. They measured the degree of degeneration and regeneration of olfactory nerve fibers and compared the effects of dexamethasone treatment after olfactory nerve injury. They found a significant decrease in the inflammatory response to injury and improved recovery following the administration of dexamethasone.

According to Costanzo, the olfactory injury models used in this study will help researchers to better understand the mechanisms underlying injury and recovery processes in the olfactory system and provide opportunities to explore new therapeutic interventions targeted at improving neuronal regeneration and functional recovery.

The findings were published online on July 3 in the Advance Access issue of the journal Chemical Senses. The work was supported by grants from the National Institutes on Deafness and Other Communication Disorders, and Thomas F. and Kate Miller Jeffress Memorial Trust.