Improvements in diagnosis and treatment of olfactory disease will require first, a more comprehensive analysis of the anatomical status of the olfactory periphery (the 1 cm2 areas on the nasal septum and the lateral nasal wall immediately inferior to the cribriform plate) with respect to the preservation of the olfactory epithelium (OE) and, second, a means of determining whether the OE's inherent capacity to reconstitute itself remains intact. We propose three specific aims designed to address our shortcomings with respect to the pathological bases of peripheral olfactory dysfunction.
Aim 1 : We observe a better than expected preservation of OE in the olfactory area of autopsy specimens, but immature neurons are abnormally prominent. We will test the hypothesis that areas in which immature neurons predominate are disconnected from the OB by using immunohistochemical analysis and DiI/DiO tracing of axons.
Aim 2 : The intermingling of OE and RE in the olfactory area and the occurrence of quiescent, aneuronal OE indicate that dysfunction of olfactory stem cells and progenitor cells contributes to peripheral olfactory pathology. Guided by our studies of the molecular profile of stem and progenitor cells in mouse and rat OE, we will identify markers for identifying neurocompetent stem and progenitor cells in human OE. We will screen for and analyze the expression of the human homologues of genes that are relevant in mouse using RT-PCR, IHC and in situ hybridization on human olfactory tissue collected by biopsy. We also plan open-ended gene profiling studies. The resulting panel can be used to assay for the stems and progenitors in human olfactory tissue.
Aim 3 : To test the usefulness of the stem/progenitor marker panel and the analysis of axon trajectory for the diagnosis of dysosmic patients. Guided by our studies of the olfactory area in Aim 1 we will harvest biopsies of the olfactory area from patients rendered dysosmic as a consequence of aging, chronic rhinosinusitis, or prior viral URI, and use our panel to analyze the status of stem and progenitor cells as well as the pattern of axonal growth within the tissue.

Public Health Relevance

By the end of the grant we will have an in-depth analysis of the distribution and connectivity of the OE at autopsy as a function of age and neurological disease and established a diagnostic panel that can elucidate more clearly the pathophysiological mechanisms underlying olfactory dysfunction. In combination, the knowledge gained can guide the eventual development of therapies for treatment of these disorders.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC010242-04
Application #
8300966
Study Section
Somatosensory and Chemosensory Systems Study Section (SCS)
Program Officer
Sullivan, Susan L
Project Start
2009-08-01
Project End
2014-07-31
Budget Start
2012-08-01
Budget End
2013-07-31
Support Year
4
Fiscal Year
2012
Total Cost
$469,007
Indirect Cost
$135,480
Name
Tufts University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
039318308
City
Boston
State
MA
Country
United States
Zip Code
02111
Holbrook, Eric H; Wu, Enming; Curry, William T et al. (2011) Immunohistochemical characterization of human olfactory tissue. Laryngoscope 121:1687-701