How fiber bundle alterations differ in presumed LATE and amnestic Alzheimer's disease.

INTRODUCTION: Typical Alzheimer's disease (AD) and limbic-predominant age-related TAR DNA-binding protein 43 (TDP-43) encephalopathy (LATE) are two neurodegenerative diseases that present with a similar initial amnestic clinical phenotype but are associated with distinct proteinopathies. METHODS: We investigated white matter (WM) fiber bundle alterations, using fixel-based analysis, a state-of-the-art diffusion magnetic resonance imaging model, in early AD, presumed LATE, and controls. We also investigated regional cortical atrophy. RESULTS: Both amnestic AD and presumed LATE patients exhibited WM alterations in tracts of the temporal and limbic lobes and in callosal fibers connecting superior frontal gyri. In addition, presumed LATE patients showed alterations in callosal fibers connecting the middle frontal gyri and in the cerebello-thalamo-cortical tract. Cortical thickness was reduced in regions connected by the most altered tracts. DISCUSSION: These findings, the first to describe WM fiber bundle alterations in presumed LATE, are consistent with results on cortical atrophy and with the staging system of tau or TDP-43 accumulation. HIGHLIGHTS: Fixel-based analysis revealed white matter (WM) fiber bundle alterations in presumed limbic-predominant age-related TAR DNA-binding protein 43 encephalopathy (LATE) patients identified by isolated episodic/limbic amnesia, the absence of positive Alzheimer's disease (AD) biomarkers, and no other neurological diagnosis after 2 years of follow-up. Presumed LATE and amnestic AD shared similar patterns of WM alterations in fiber bundles of the limbic and temporal lobes, in congruence with their similar limbic cognitive phenotype. Presumed LATE differed from AD by the alteration of the callosal fibers connecting the middle frontal gyri and of the cerebello-thalamo-cortical tract. WM fiber bundle alterations were consistent with results on regional cortical atrophy. The different anatomical patterns of WM degeneration could provide information on the propagation pathways of distinct proteinopathies.

What you Need to Know about the New Regulations for Biomedical Research in France.

The EC 2001/20 directive relating to the clinical trials of medicinal products was transposed into French law in 2004 by means of a public health law. But this transposition actually came into effect on 27 August 2006 by the implementation of decree no. 2006-477 of 26 April 2006 which has been followed subsequently by numerous statutory orders. A reading of these regulatory texts shows that the new provisions go far beyond the framework of the directive as they have been notably extended by the French legislator to encompass all the health products within the competence of the French Agency for Sanitary Safety in Health Products (Afssaps) as well as to other studies that do not involve health products. In addition, all research undertaken is from now subject to the prior, and jointly favourable, reasoned opinion of a CPP (Ethic Committee) and authorisation by Afssaps. These new regulations for biomedical research in France substantially modify and reinforce the previous provisions defined by the Huriet law of 1988, for safety, vigilance and traceability.

What you need to know about the new regulations for biomedical research in France.

The EC 2001/20 directive relating to the clinical trials of medicinal products was transposed into French law in 2004 by means of a public health law. But this transposition actually came into effect on 27 August 2006 by the implementation of decree no. 2006-477 of 26 April 2006 which has been followed subsequently by numerous statutory orders. A reading of these regulatory texts shows that the new provisions go far beyond the framework of the directive as they have been notably extended by the French legislator to encompass all the health products within the competence of the French Agency for Sanitary Safety in Health Products (Afssaps) as well as to other studies that do not involve health products. In addition, all research undertaken is from now subject to the prior, and jointly favourable, reasoned opinion of a CPP (Ethic Committee) and authorisation by Afssaps. These new regulations for biomedical research in France substantially modify and reinforce the previous provisions defined by the Huriet law of 1988, for safety, vigilance and traceability.