ANA TEREZA DI LORENZO ALHO
Projetos de Pesquisa
Unidades Organizacionais
LIM/44 - Laboratório de Ressonância Magnética em Neurorradiologia, Hospital das Clínicas, Faculdade de Medicina
3 resultados
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- Magnetic resonance diffusion tensor imaging for the pedunculopontine nucleus: proof of concept and histological correlation(2017) ALHO, A. T. D. L.; HAMANI, C.; ALHO, E. J. L.; SILVA, R. E. da; SANTOS, G. A. B.; NEVES, R. C.; CARREIRA, L. L.; ARAUJO, C. M. M.; MAGALHAES, G.; COELHO, D. B.; ALEGRO, M. C.; MARTIN, M. G. M.; GRINBERG, L. T.; PASQUALUCCI, C. A.; HEINSEN, H.; FONOFF, E. T.; AMARO JR., E.The pedunculopontine nucleus (PPN) has been proposed as target for deep brain stimulation (DBS) in patients with postural instability and gait disorders due to its involvement in muscle tonus adjustments and control of locomotion. However, it is a deep-seated brainstem nucleus without clear imaging or electrophysiological markers. Some studies suggested that diffusion tensor imaging (DTI) may help guiding electrode placement in the PPN by showing the surrounding fiber bundles, but none have provided a direct histological correlation. We investigated DTI fractional anisotropy (FA) maps from in vivo and in situ postmortem magnetic resonance images (MRI) compared to histological evaluations for improving PPN targeting in humans. A post-mortem brain was scanned in a clinical 3T MR system in situ. Thereafter, the brain was processed with a special method ideally suited for cytoarchitectonic analyses. Also, nine volunteers had in vivo brain scanning using the same MRI protocol. Images from volunteers were compared to those obtained in the post-mortem study. FA values of the volunteers were obtained from PPN, inferior colliculus, cerebellar crossing fibers and medial lemniscus using histological data and atlas information. FA values in the PPN were significantly lower than in the surrounding white matter region and higher than in areas with predominantly gray matter. In Nissl-stained histologic sections, the PPN extended for more than 10 mm in the rostro-caudal axis being closely attached to the lateral parabrachial nucleus. Our DTI analyses and the spatial correlation with histological findings proposed a location for PPN that matched the position assigned to this nucleus in the literature. Coregistration of neuroimaging and cytoarchitectonic features can add value to help establishing functional architectonics of the PPN and facilitate neurosurgical targeting of this extended nucleus.
- Quantifying the accretion of hyperphosphorylated tau in the locus coeruleus and dorsal raphe nucleus: the pathological building blocks of early Alzheimer's disease(2017) EHRENBERG, A. J.; NGUY, A. K.; THEOFILAS, P.; DUNLOP, S.; SUEMOTO, C. K.; ALHO, A. T. Di Lorenzo; LEITE, R. P.; RODRIGUEZ, R. Diehl; MEJIA, M. B.; RUEB, U.; FARFEL, J. M.; FERRETTI-REBUSTINI, R. E. de Lucena; NASCIMENTO, C. F.; NITRINI, R.; PASQUALLUCCI, C. A.; JACOB-FILHO, W.; MILLER, B.; SEELEY, W. W.; HEINSEN, H.; GRINBERG, L. T.AimsHyperphosphorylated tau neuronal cytoplasmic inclusions (ht-NCI) are the best protein correlate of clinical decline in Alzheimer's disease (AD). Qualitative evidence identifies ht-NCI accumulating in the isodendritic core before the entorhinal cortex. Here, we used unbiased stereology to quantify ht-NCI burden in the locus coeruleus (LC) and dorsal raphe nucleus (DRN), aiming to characterize the impact of AD pathology in these nuclei with a focus on early stages.MethodsWe utilized unbiased stereology in a sample of 48 well-characterized subjects enriched for controls and early AD stages. ht-NCI counts were estimated in 60-m-thick sections immunostained for p-tau throughout LC and DRN. Data were integrated with unbiased estimates of LC and DRN neuronal population for a subset of cases.ResultsIn Braak stage 0, 7.9% and 2.6% of neurons in LC and DRN, respectively, harbour ht-NCIs. Although the number of ht-NCI+ neurons significantly increased by about 1.9x between Braak stages 0 to I in LC (P = 0.02), we failed to detect any significant difference between Braak stage I and II. Also, the number of ht-NCI+ neurons remained stable in DRN between all stages 0 and II. Finally, the differential susceptibility to tau inclusions among nuclear subdivisions was more notable in LC than in DRN.ConclusionsLC and DRN neurons exhibited ht-NCI during AD precortical stages. The ht-NCI increases along AD progression on both nuclei, but quantitative changes in LC precede DRN changes.
- Locus coeruleus volume and cell population changes during Alzheimer's disease progression: A stereological study in human postmortem brains with potential implication for early-stage biomarker discovery(2017) THEOFILAS, Panos; EHRENBERG, Alexander J.; DUNLOP, Sara; ALHO, Ana T. Di Lorenzo; NGUY, Austin; LEITE, Renata Elaine Paraizo; RODRIGUEZ, Roberta Diehl; MEJIA, Maria B.; SUEMOTO, Claudia K.; FERRETTI-REBUSTINI, Renata Eloah De Lucena; POLICHISO, Livia; NASCIMENTO, Camila F.; SEELEY, William W.; NITRINI, Ricardo; PASQUALUCCI, Carlos Augusto; JACOB FILHO, Wilson; RUEB, Udo; NEUHAUS, John; HEINSEN, Helmut; GRINBERG, Lea T.Introduction: Alzheimer's disease (AD) progression follows a specific spreading pattern, emphasizing the need to characterize those brain areas that degenerate first. The brainstem's locus coeruleus (LC) is the first area to develop neurofibrillary changes (neurofibrillary tangles [NFTs]). Methods: The methods include unbiased stereologiCal analyses in human brainstems to estimate LC volume and neuronal population in controls and individuals across all AD stages. Results: As the Braak stage increases by 1 unit, the LC volume decreases by 8.4%. Neuronal loss started only midway through AD progression. Age-related changes spare the LC. Discussion: The long gap between NFT accumulation and neuronal loss suggests that a second trigger may be necessary to induce neuronal death in AD. Imaging studies should determine whether LC volumetry can replicate the stage-wise atrophy observed here and how these changes are specific to AD. LC volumetry may develop into a screening biomarker for selecting high-yield candidates to undergo expensive and less accessible positron emission tomography scans and to monitor AD progression from presymptomatic stages.