Maastricht University

About: Maastricht University is a education organization based out in Maastricht, Limburg, Netherlands. It is known for research contribution in the topics: Population & Health care. The organization has 19263 authors who have published 53291 publications receiving 2266866 citations. The organization is also known as: Universiteit Maastricht & UM.

Massive CA1/2 Neuronal Loss with Intraneuronal and N-Terminal Truncated Aβ42 Accumulation in a Novel Alzheimer Transgenic Model

Abstract: Alzheimer's disease (AD) is characterized by a substantial degeneration of pyramidal neurons and the appearance of neuritic plaques and neurofibrillary tangles. Here we present a novel transgenic mouse model, APP(SL)PS1KI that closely mimics the development of AD-related neuropathological features including a significant hippocampal neuronal loss. This transgenic mouse model carries M233T/L235P knocked-in mutations in presenilin-1 and overexpresses mutated human beta-amyloid (Abeta) precursor protein. Abeta(x-42) is the major form of Abeta species present in this model with progressive development of a complex pattern of N-truncated variants and dimers, similar to those observed in AD brain. At 10 months of age, an extensive neuronal loss (>50%) is present in the CA1/2 hippocampal pyramidal cell layer that correlates with strong accumulation of intraneuronal Abeta and thioflavine-S-positive intracellular material but not with extracellular Abeta deposits. A strong reactive astrogliosis develops together with the neuronal loss. This loss is already detectable at 6 months of age and is PS1KI gene dosage-dependent. Thus, APP(SL)PS1KI mice further confirm the critical role of intraneuronal Abeta(42) in neuronal loss and provide an excellent tool to investigate therapeutic strategies designed to prevent AD neurodegeneration.

IDO and interferon-alpha-induced depressive symptoms: a shift in hypothesis from tryptophan depletion to neurotoxicity

Abstract: Studies show that administration of interferon (IFN)-α causes a significant increase in depressive symptoms. The enzyme indoleamine 2,3-dioxygenase (IDO), which converts tryptophan (TRP) into kynurenine (KYN) and which is stimulated by proinflammatory cytokines, may be implicated in the development of IFN-α-induced depressive symptoms, first by decreasing the TRP availability to the brain and second by the induction of the KYN pathway resulting in the production of neurotoxic metabolites. Sixteen patients with chronic hepatitis C, free of psychiatric disorders and eligible for IFN-α treatment, were recruited. Depressive symptoms were measured using the Montgomery Asberg Depression Rating Scale (MADRS). Measurements of TRP, amino acids competing with TRP for entrance through the blood–brain barrier, KYN and kynurenic acid (KA), a neuroprotective metabolite, were performed using high-performance liquid chromatography. All assessments were carried out at baseline and 1, 2, 4, 8, 12 and 24 weeks after treatment was initiated. The MADRS score significantly increased during IFN-α treatment as did the KYN/TRP ratio, reflecting IDO activity, and the KYN/KA ratio, reflecting the neurotoxic challenge. The TRP/CAA (competing amino acids) ratio, reflecting TRP availability to the brain, did not significantly change during treatment. Total MADRS score was significantly associated over time with the KYN/KA ratio, but not with the TRP/CAA ratio. Although no support was found that IDO decreases TRP availability to the brain, this study does support a role for IDO activity in the pathophysiology of IFN-α-induced depressive symptoms, through its induction of neurotoxic KYN metabolites.

Requirement for CD154 in the progression of atherosclerosis.

Abstract: Atherosclerosis is a systemic disease of the large arteries, and activation of inflammatory pathways is important in its pathogenesis1. Increasing evidence supports the importance of CD40–CD154 interactions in atherosclerosis2,3, interactions originally known to be essential in major immune reactions4 and autoimmune diseases5. CD40 is present on atheroma-derived cells in vitro and in human atheromata in situ6. Ligation of CD40 on atheroma-associated cells in vitro activates the production of chemokines6, cytokines6, matrix metalloproteinases7,8, adhesion molecules9,10 and tissue factor7, substances responsible for lesion progression and plaque destabilization1. Administration of antibody against CD154 to low-density lipoprotein receptor-deficient mice has been shown to reduce atherosclerosis and decrease T-lymphocyte and macrophage content; however, only initial lesions were studied3. Here, we determined the effect of genetic disruption of CD154 in ApoE–/– mice in both initial and advanced atherosclerotic lesions. Plaque area was reduced 550%. In contrast to previous reports, initial lesion development was not affected. Advanced plaques in CD154–/–ApoE–/– mice had a less-lipid-containing, collagen-rich, stable plaque phenotype, with a reduced T-lymphocyte/macrophage content. These data indicate that CD40–CD154 signaling is important in late atherosclerotic changes, such as lipid core formation and plaque destabilization.

The genetic architecture of the human cerebral cortex

Abstract: The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder.