RESUMO
Schizophrenia is a mental disorder characterized by delusions, hallucinations, disorganization in speech and thinking as well as alterations in social behavior, and affective flattening. Schizophrenic patients also have an olfactory deficit since prodromal stages of this disorder. The olfactory deficit could be present in schizophrenic patients due to anatomic and structural alteration of the Central Nervous System, or peripheral abnormalities in the olfactory epithelium. The major alterations of the Central Nervous System are diminished volumes of olfactory bulb and structures of primary olfactory cortex, hippocampus and amygdala. While, olfactory epithelium has functional abnormalities in cellular differentiation and electric response of sensory olfactory neurons, which suggest an impairment of the odor transduction. The cellular culture of olfactory epithelium has allowed isolating multipotential progenitor cells that have the ability to proliferate and differentiate in mature neurons and glia. This model could provide evidences on the causes that could explain the olfactory deficits in schizophrenia. Moreover, it will allow testing hypothesis on pathophysiological causes of this mental disorder in different of stages of the neurodevelopment. In addition, olfactory epithelial neuronal precursors constitute a novel model to detect genetic, proteomic and functional biomarkers that allow a biological diagnosis.
La esquizofrenia (EZ) es un trastorno psiquiátrico que se caracteriza por la presencia de delirios, alucinaciones, pensamiento desorganizado, lenguaje desestructurado, alteraciones del comportamiento social y aplanamiento afectivo, entre otros síntomas. Los pacientes con EZ también presentan un déficit en la capacidad olfatoria desde la fase prodrómica del trastorno. El déficit olfatorio en la EZ puede presentarse por alteraciones anatómico-estructurales del SNC o por anomalías a nivel periférico en el epitelio olfatorio. Las alteraciones principales del SNC son la disminución del volumen de los bulbos olfatorios, de estructuras de la corteza olfatoria primaria, del hipocampo y de la amígdala coronal. El epitelio olfatorio en los estadios tempranos de la EZ presenta anomalías funcionales en la diferenciación y en la respuesta biofísica de las neuronas sensoriales olfatorias, lo que sugiere que existe un desacoplamiento de la transducción olfatoria. El cultivo celular del epitelio olfatorio ha permitido aislar células progenitoras multipotenciales que poseen la capacidad de proliferar y diferenciarse en neuronas y glía. El estudio de este modelo podría aportar evidencia sobre las causas que explicarían el déficit olfatorio en la esquizofrenia y permitiría estudiar hipótesis que intenten explicar las causas de la fisiopatología de este trastorno en el neurodesarrollo así como detectar biomarcadores genéticos, proteómicos o funcionales que permitan un diagnóstico biológico.
RESUMO
BACKGROUND: Dementia has emerged as a major healthy challenge, not only for clinicians but for society as a whole. So, there is a growing need for study of dementia. Evaulating the patients with dementia, examination of the sense of smell is not routinely performed. However, one of several neurologic changes include alterations in olfaction. OBJECTIVES: The aim of this study was to evaluate the value of olfactory function test in demented patients as diagnostic tool. MATERIALS AND METHOD: We studied the olfactory functions in 35 patients with dementia of the Alzheimer's type(DAT) and 20 patients with vascular dementia(VD) and compared with normal controls(n=30). These subjects were divided according to the Mini-Mental State Examination(MMSE). We used the T & T olfactometer for the olfactory function test. RESULTS: In the group of questionable DAT, the detection and recognition threshold were 0.25+/-0.95, 2.38+/-1.87, in the group of definitive DAT, 1.51+/-1.52, 3.91+/-1.55 and in the group of definitive vascular dementia, 2.03+/-1.48, 4.53+/-1.45. But, in the normal controls, the detection and recognition threshold was 0.66+/-0.90, 1.55+/-0.81 respectively. CONCLUSION: These findings suggest that olfactory function test are valuable in demented patients as diagnostic tool, but not specific in DAT group and that early detection of DAT is possible by olfactory function test.