Olfactory neuroepithelium in the superior and middle turbinates: which is the optimal biopsy site?

INTRODUCTION: Olfactory neuroepithelium (ON) biopsy has several therapeutic applications for both disorders of olfaction and neurodegenerative diseases. Successful collection of ON is still anything but routine due to a dearth of studies on the distribution of ON in the superior and middle turbinates. AIM: To determine the location in which ON is most likely to be present in endoscopically removed cadaver superior and middle turbinates as well as the influences of gender, age, and naris side on the presence of ON and the extent to which it is present. METHODS: We conducted a prospective anatomical study. The superior and middle turbinates on both sides endoscopically removed from 25 fresh cadavers (less than 12 h post-mortem). The turbinates were halved into anterior and posterior segments for a total of 200 specimens, which were analyzed after hematoxylin and eosin and immunohistochemical staining. Hematoxylin and eosin-stained slides were subjected to blind examination by 3 independent pathologists, and the presence of ON was graded on a 5-point scale from 0 to 4. Kappa measurement was used to determine the agreement between pairs of observers. RESULTS: ON was present in 82.9% of superior turbinate samples and in 17.1% of middle turbinate samples. Immunohistochemistry detected ON in superior turbinates only by S-100 staining and only in 15 fragments. Gender, age, and naris side had no statistically significant effects on the presence of ON. CONCLUSION: When biopsying ON, the posterior portion of the superior turbinate should be targeted whenever possible because it has the highest concentration of ON among the nasal structures.

Effect of diabetes mellitus on the olfactory mucosa: an experimental study

To investigate the effect of diabetes mellitus [DM] on the olfactory mucosa, an experimental study was performed with 60 albino rats from the same colony and age. The animals were divided into two groups, consisting of 10 animals as a control group [CG] and 50 animals as a diabetic group [DG], DM was induced by intraperitoneal injection of alloxan in a dose of 210 mg/kg of body weight. Widened intercellular spaces, thining of epithelial and mucous layers desquamation, ciliary loss and neural bundles atrophy [15%] were observed in DG. These changes increased by severity of diabetes and its duration. The reported atrophy may be due to genetic factors in some animals predisposing to pathogenesis of diabetic neuropathy. More or less the changes were reported in CG except neural bundles atrophy. The changes in CG were much less severe than in DG and increased by aging. The role of DM in these changes was suggested to be acceleration and exaggeration of degenerative process of aging, disharmony of regular rhythm of replication and degeneration cycles and/or renewal of basal cells and consequently failure of renewal process of sensory cells and their axonal projections. The results of this study suggested, that olfactory dysfunction with DM is a complicated process and the integrity of olfactory mucosa represents a part of its dilemma. It was advised to do meticulous control of DM as it may improve the central and peripheral process of olfaction. Also, it was concluded that the olfactory dysfunction in diabetics is still a fertile area for further studies