Cathepsin B-associated Activation of Amyloidogenic Pathway in Murine Mucopolysaccharidosis Type I Brain Cortex

Mucopolysaccharidosis type I (MPS I) is caused by genetic deficiency of alpha-l-iduronidase and impairment of lysosomal catabolism of heparan sulfate and dermatan sulfate. In the brain, these substrates accumulate in the lysosomes of neurons and glial cells, leading to neuroinflammation and neurodegeneration. Their storage also affects lysosomal homeostasis-inducing activity of several lysosomal proteases including cathepsin B (CATB). In the central nervous system, increased CATB activity has been associated with the deposition of amyloid plaques due to an alternative pro-amyloidogenic processing of the amyloid precursor protein (APP), suggesting a potential role of this enzyme in the neuropathology of MPS I. In this study, we report elevated levels of protein expression and activity of CATB in cortex tissues of 6-month-old MPS I (Idua -/- mice. Besides, increased CATB leakage from lysosomes to the cytoplasm of Idua -/- cortical pyramidal neurons was indicative of damaged lysosomal membranes. The increased CATB activity coincided with an elevated level of the 16-kDa C-terminal APP fragment, which together with unchanged levels of beta-secretase 1 was suggestive for the role of this enzyme in the amyloidogenic APP processing. Neuronal accumulation of Thioflavin-S-positive misfolded protein aggregates and drastically increased levels of neuroinflammatory glial fibrillary acidic protein (GFAP)-positive astrocytes and CD11b-positive activated microglia were observed in Idua -/- cortex by confocal fluorescent microscopy. Together, our results point to the existence of a novel CATB-associated alternative amyloidogenic pathway in MPS I brain induced by lysosomal storage and potentially leading to neurodegeneration

Care interruptions and mortality among adults in Europe and North America: a collaborative analysis of cohort studies.

OBJECTIVE: Interruptions in care of people with HIV (PWH) on antiretroviral therapy (ART) are associated with adverse outcomes, but most studies have relied on composite outcomes. We investigated whether mortality risk following care interruptions differed from mortality risk after first starting ART. DESIGN: Collaboration of 18 European and North American HIV observational cohort studies of adults with HIV starting ART between 2004-2019. METHODS: Care interruptions were defined as gaps in contact of ≥365 days, with a subsequent return to care (distinct from loss to follow-up), or ≥270 days and ≥545 days in sensitivity analyses. Follow-up time was allocated to no/pre-interruption or post-interruption follow-up groups. We used Cox regression to compare hazards of mortality between care interruption groups, adjusting for time-updated demographic and clinical characteristics and biomarkers upon ART initiation or re-initiation of care. RESULTS: Of 89197 PWH, 83.4% were male and median age at ART start was 39 years (interquartile range [IQR]: 31-48). 8654 PWH (9.7%) had ≥1 care interruption; 10913 episodes of follow-up following a care interruption were included. There were 6104 deaths in 536,334 person-years, a crude mortality rate of 11.4 (95%CI: 11.1-11.7) per 1000 person-years. The adjusted mortality hazard ratio (HR) for the post-interruption group was 1.72 (95%CI: 1.57-1.88) compared with the no/pre-interruption group. Results were robust to sensitivity analyses assuming ≥270-day (HR 1.49, 95%CI: 1.40-1.60) and ≥545-day (HR 1.67, 95%CI: 1.48-1.88) interruptions. CONCLUSIONS: Mortality was higher among PWH reinitiating care following an interruption, compared with when PWH initially start ART, indicating the importance of uninterrupted care

Influence of Feedstock Powder Modification by Heat Treatments on the Properties of APS-Sprayed Al2O3-40% TiO2 Coatings27

The formation and decomposition of aluminum titanate (Al2TiO5, tialite) in feedstock powders and coatings of the binary Al2O3-TiO2 system are so far poorly understood. A commercial fused and crushed Al2O3-40%TiO2 powder was selected as the feedstock for the experimental series presented in this paper, as the composition is close to that of Al2TiO5. Part of that powder was heat-treated in air at 1150 and 1500 °C in order to modify the phase composition, while not influencing the particle size distribution and processability. The powders were analyzed by thermal analysis, XRD and FESEM including EDS of metallographically prepared cross sections. Only a maximum content of about 45 wt.% Al2TiO5 was possible to obtain with the heat treatment at 1500 °C due to inhomogeneous distribution of Al and Ti in the original powder. Coatings were prepared by plasma spraying using a TriplexPro-210 (Oerlikon Metco) with Ar-H2 and Ar-He plasma gas mixtures at plasma power levels of 41 and 48 kW. Coatings were studied by XRD, SEM including EDS linescans of metallographically prepared cross sections, and microhardness HV1. With the exception of the powder heat-treated at 1500 °C an Al2TiO5-Ti3O5 (tialite–anosovite) solid solution Al2−xTi1+xO5 instead of Al2TiO5 existed in the initial powder and the coatings