Biomedical subjects

Benoît Février

Publications and source records attributed to Benoît Février.

3 recordsLinked to original sources

PubMed2005

Common carotid artery intima-media thickness, carotid plaques, and walking speed.

BACKGROUND AND PURPOSE: Gait dysfunction is an important cause of disability among the elderly and may be, in part, of vascular origin. We studied the association between carotid ultrasound parameters and measures of gait and balance in subjects 65 to 85 years of age who participated in the baseline phase of the Three-City Study in the Dijon center. METHODS: The study population comprised 2572 noninstitutionalized individuals. Carotid plaques and common carotid artery intima-media thickness (CCA-IMT) were measured using ultrasonography. Gait and balance measures included walking speed and a modified version of the Tinetti scale. RESULTS: Mean maximum walking speed (MWS) decreased with increasing CCA-IMT and number of plaques (P<10(-4)). Compared with subjects in the lowest CCA-IMT quintile, the odds ratio (95% CI) for being in the lowest MWS quartile was 1.1 (0.8 to 1.6) in the second, 1.3 (0.9 to 1.8) in the third, 1.7 (1.2 to 2.4) in the fourth, and 2.2 (1.6 to 3.1) in the higher CCA-IMT quintile (P<10(-4)). Mean (SD) CCA-IMT was 0.716 (0.118) mm in subjects with a modified Tinetti score <16 (25th percentile) and 0.685 (0.109) mm in subjects with a score of > or =16 (P=0.006). The proportion of subjects in the lowest MWS quartile (P=0.006) or with a modified Tinetti score <16 (P=0.05) increased with the number of plaques. These relations were attenuated after adjustment for vascular risk factors. CONCLUSIONS: Carotid plaques and higher CCA-IMT values are associated with worse performances on gait and balance tests. Our results suggest that vascular factors may play an important and under-recognized role in motor function.

Aged↗

PubMed2005

Exosomes: a bubble ride for prions?

In certain cell types, endosomal multivesicular bodies may fuse with the cell surface in an exocytic manner. During this process, the small 50-90-nm-diameter vesicles contained in their lumen are released into the extracellular environment. The released vesicles are called exosomes. Exosome secretion can be used by cells to eject molecules targeted to intraluminal vesicles of multivesicular bodies, but particular cell types exploit exosomes as intercellular communication devices for transfer of proteins and lipids between cells. The molecular composition of exosomes is determined by sorting events within endosomes that occur concomitantly with the generation of intraluminal vesicles. As other raft-associated components, the glycosylphosphatidylinositol-linked prion protein transits through multivesicular bodies. Recent findings in non-neuronal cell models indicate prion protein association with secreted exosomes. Thus, exosomes could constitute vehicles for transmission of the infectious prion protein, bypassing cell-cell contact in the dissemination of prions.

Animals↗

PubMedDate not supplied

Prions and exosomes: from PrPc trafficking to PrPsc propagation.

Exosomes are membrane vesicles released into the extracellular environment upon exocytic fusion of multivesicular endosomes with the cell surface. Exosome secretion can be used by cells to eject molecules targeted to intraluminal vesicles of multivesicular bodies, but particular cell types may exploit exosomes as intercellular communication devices for transfer of proteins and lipids among cells. The glycosylphosphatyidylinositol-linked prion protein (PrP) in both its normal (PrPc) and scrappie (PrPsc) conformation is associated with exosomes. Targeting of exosomes containing the normal cellular PrP could confer susceptibility of cells that do not express PrP to prion multiplication. Furthermore, exosomes bearing proteinase-K resistant PrPsc are infectious, suggesting a model in which exosomes secreted by infected cells could serve as vehicles for propagation of prions. Thus, cells may exploit the nature of endosome-derived exosomes to communicate with each other in normal and pathological situations, providing for a novel route of cell-to-cell communication and therefore of pathogen transmission. These findings open the possibility that methods to interfere with trafficking of such unconventional pathogens could be envisioned from insights on the mechanisms involved in exosome formation, secretion and targeting.

Cell Communication↗