[Olfactory mucosa and Alzheimer's disease. Technique for biopsy and ultrastructural study]

The discovery of a reliable peripheral marker would be of a great interest for the early diagnosis of the Alzheimer's Disease. The olfactory deficit and the major histologic changes of the olfactory-related areas of the brain occurring during this disease raised the possibility that the olfactory epithelia could be one of the way of entry of a possible process that still has to be identified. We have developed an instrument and a technique of biopsy of the human olfactory mucosa to search for the presence of characteristics lesions on patients suffering of an Alzheimer's Disease. These small specimens have been prepared for electronic microscopy. The ultrastructural study of a sample of olfactory mucosa has been realised in 9 cases (5 Alzheimer's-4 controls) revealing in 4 patients suspected of an Alzheimer's Disease a complete architectural disorganisation with a destruction of the dendrite of the olfactory cells and a severe degeneration of the sustentacular cells. We did not find any characteristic changes such as Paired Helicoidal Filaments or amyloid fibrils. These results do not presuppose of their eventual presence at a precocious stage of the disease. Further ultrastructural and immunochemical studies carried out with patients at various stages of the disease are necessary in order to confirm this hypothesis.