Glial calcium signalling in Alzheimer's disease.

The most accredited (and fashionable) hypothesis of the pathogenesis of Alzheimer Disease (AD) sees accumulation of ß-amyloid protein in the brain (in both soluble and insoluble forms) as a leading mechanism of neurotoxicity. How ß-amyloid triggers the neurodegenerative disorder is at present unclear, but growing evidence suggests that a deregulation of Ca(2+) homeostasis and deficient Ca(2+) signalling may represent a fundamental pathogenic factor. Given that symptoms of AD are most likely linked to synaptic dysfunction (at the early stages) followed by neuronal loss (at later and terminal phases of the disease), the effects of ß-amyloid have been mainly studied in neurones. Yet, it must be acknowledged that neuroglial cells, including astrocytes, contribute to pathological progression of most (if not all) neurological diseases. Here, we review the literature pertaining to changes in Ca(2+) signalling in astrocytes exposed to exogenous ß-amyloid or in astrocytes from transgenic Alzheimer disease animals models, characterized by endogenous ß-amyloidosis. Accumulated experimental data indicate deregulation of Ca(2+) homeostasis and signalling in astrocytes in AD, which should be given full pathogenetic consideration. Further studies are warranted to comprehend the role of deficient astroglial Ca(2+) signalling in the disease progression.

Amyloid beta deregulates astroglial mGluR5-mediated calcium signaling via calcineurin and Nf-kB.

The amyloid hypothesis of Alzheimer's disease (AD) suggests that soluble amyloid ß (Aß) is an initiator of a cascade of events eventually leading to neurodegeneration. Recently, we reported that Aß deranged Ca(2+) homeostasis specifically in hippocampal astrocytes by targeting key elements of Ca(2+) signaling, such as mGluR5 and IP3 R1. In the present study, we dissect a cascade of signaling events by which Aß deregulates glial Ca(2+) : (i) 100 nM Aß leads to an increase in cytosolic calcium after 4-6 h of treatment; (ii) mGluR5 is increased after 24 h of treatment; (iii) this increase is blocked by inhibitors of calcineurin (CaN) and NF-kB. Furthermore, we show that Aß treatment of glial cells leads to de-phosphorylation of Bcl10 and an increased CaN-Bcl10 interaction. Last, mGluR5 staining is augmented in hippocampal astrocytes of AD patients in proximity of Aß plaques and co-localizes with nuclear accumulation of the p65 NF-kB subunit and increased staining of CaNAα. Taken together our data suggest that nanomolar [Aß] deregulates Ca(2+) homeostasis via CaN and its downstream target NF-kB, possibly via the cross-talk of Bcl10 in hippocampal astrocytes.

Price and reimbursement of advanced therapeutic medicinal products in Europe: are assessment and appraisal diverging from expert recommendations?

BACKGROUND: Advanced therapy medicinal products (ATMPs) represent an important cornerstone for innovation in healthcare. However, uncertainty on the value, the high average cost per patient and their one-shot nature has raised a debate on their assessment and appraisal process for pricing and reimbursement (P&R) purposes. This debate led experts providing for recommendations on this topic. Our primary objective is to investigate the ATMPs P&R process in the main five European countries and to understand if this process is consistent with published P&R expert recommendations. We also investigated the current ATMP pipelines to understand if future ATMPs will create challenges for their P&R process. METHODS: P&R framework for ATMPs in the European Major five (EU5) countries was investigated through a literature search on PubMed, institutional websites of National Health Authorities and grey literature. The ATMPs pipeline database was populated from a clinical trial database (clinicaltrials.gov), relying on inclusion and exclusion criteria retrieved from the literature. RESULTS: Reimbursement status of ATMPs is different across the EU5 countries, with the exception of CAR-Ts which are reimbursed in all countries. Standard P&R process in place for other medicinal products is extended to ATMPs, with the exception of some cases in Germany. List prices, where available, are high and, tend to be aligned across countries. Outcome-based Managed Entry Agreements (MEAs) have been extensively used for ATMPs. Extra-funds for hospitals managing ATMPs were provided only in Germany and, as additional fund per episode, in France. The accreditation process of hospitals for ATMPs management was in most countries managed by the national authorities. As far as ATMPs pipeline is concerned, ATMPs in development are mostly targeting non-rare diseases. CONCLUSIONS: Expert recommendations for ATMPs P&R were partially applied: the role of outcome-based MEAs has increased and the selection process of the centres authorized to use these treatments has been enhanced; additional funding for ATMPs management to accredited centres has not been completely considered and annuity payment and broader perspective in cost considerations are far from being put in place. These recommendations should be considered for future P&R negotiations to pursue rational resource allocation and deal with budget constraints.

Primary Biliary Cholangitis: advances in management and treatment of the disease.

Primary Biliary Cholangitis, previously known as Primary Biliary Cirrhosis, is a rare disease, which mainly affects women in their fifth to seventh decades of life. It is a chronic autoimmune disease characterized by a progressive damage of interlobular bile ducts leading to ductopenia, chronic cholestasis and bile acids retention. Even if the disease usually presents a long asymptomatic phase and a slow progression, in many patients it may progress faster toward cirrhosis and its complications. The 10year mortality is greater than in diseases such as human immunodeficiency virus/Hepatitis C Virus coinfection and breast cancer. Ursodeoxycholic acid is the only treatment available today, but even if effective in counteracting the disease progression for the majority of patients, in approximately 40% is not able to decrease effectively the alkaline phosphatase, a surrogate marker of disease activity. Recently, obeticholic acid received the European Medicines Agency conditional approval, as add on treatment in patients non responders or intolerant to ursodeoxycholic acid. The present paper illustrates the opinion of a working group, composed by clinical pharmacologists, gastroenterologists/hepatologists with specific expertise on Primary Biliary Cholangitis and patient associations, on the state of the art and future perspectives of the disease management. The agreement on the document was reached through an Expert Meeting.

A novel Ca²âº-mediated cross-talk between endoplasmic reticulum and acidic organelles: implications for NAADP-dependent Ca²âº signalling.

Nicotinic acid adenine dinucleotide phosphate (NAADP) serves as the ideal trigger of spatio-temporally complex intracellular Ca(2+) signals. However, the identity of the intracellular Ca(2+) store(s) recruited by NAADP, which may include either the endolysosomal (EL) or the endoplasmic reticulum (ER) Ca(2+) pools, is still elusive. Here, we show that the Ca(2+) response to NAADP was suppressed by interfering with either EL or ER Ca(2+) sequestration. The measurement of EL and ER Ca(2+) levels by using selectively targeted aequorin unveiled that the preventing ER Ca(2+) storage also affected ER Ca(2+) loading and vice versa. This indicates that a functional Ca(2+)-mediated cross-talk exists at the EL-ER interface and exerts profound implications for the study of NAADP-induced Ca(2+) signals. Extreme caution is warranted when dissecting NAADP targets by pharmacologically inhibiting EL and/or the ER Ca(2+) pools. Moreover, Ca(2+) transfer between these compartments might be essential to regulate vital Ca(2+)-dependent processes in both organelles.

Differential deregulation of astrocytic calcium signalling by amyloid-ß, TNFα, IL-1ß and LPS.

In Alzheimer's disease (AD), astrocytes undergo complex morphological and functional changes that include early atrophy, reactive activation and Ca(2+) deregulation. Recently, we proposed a mechanism by which nanomolar Aß42 deregulates mGluR5 and InsP3 receptors, the key elements of astrocytic Ca(2+) signalling toolkit. To evaluate the specificity of these changes, we have now investigated whether the effects of Aß42 on Ca(2+) signalling machinery can be reproduced by pro-inflammatory agents (TNFα, IL-1ß, LPS). Here we report that Aß42 (100nM, 72h) significantly increased mRNA levels of mGluR5, InsP3R1 and InsP3R2, whereas pro-inflammatory agents reduced expression of these specific mRNAs. Furthermore, DHPG-induced Ca(2+) signals and store operated Ca(2+) entry (SOCE) were augmented in Aß42-treated cells due to up-regulation of a set of Ca(2+) signalling-related genes including TRPC1 and TRPC4. Opposite changes were observed when astrocytes were treated with TNFα, IL-1ß and LPS. Last, the effects observed on SOCE by treating wild-type astrocytes with Aß42 were also identified in untreated astrocytes from 3×Tg-AD animals, suggesting a link to the AD pathology. Our results demonstrate that effects of Aß42 on astrocytic Ca(2+) signalling differ from and may contrast to the effects of pro-inflammatory agents.