Estrogen,migraine, and vascular risk

Migraine has a predilection for female sex and the course of symptoms is influenced by life stage (presence of menstrual cycle, pregnancy, puerperium, menopause) and use of hormone therapy, such as hormonal contraception and hormone replacement therapy. Hormonal changes figure among common migraine triggers, especially sudden estrogen drop. Moreover, estrogens can modulate neuronal excitability, through serotonin, norepinephrine, dopamine, and endorphin regulation, and they interact with the vascular endothelium of the brain. The risk of vascular disease, and ischemic stroke in particular, is increased in women with migraine with aura (MA), but the link is unclear. One hypothesis posits for a causal association: migraine may cause clinical or subclinical brain lesions following repeated episodes of cortical spreading depression (CSD) and a second hypothesis that may explain the association between migraine and vascular diseases is the presence of common risk factors and comorbidities. Estrogens can play a differential role depending on their action on healthy or damaged endothelium, their endogenous or exogenous origin, and the duration of their treatment. Moreover, platelet activity is increased in migraineurs women, and it is further stimulated by estrogens.This review article describes the course of migraine during various life stages, with a special focus on its hormonal pathogenesis and the associated risk of vascular diseases.     

Intention Understanding in Autism

When we observe a motor act (e.g. grasping a cup) done by another individual, we extract, according to how the motor act is performed and its context, two types of information: the goal (grasping) and the intention underlying it (e.g. grasping for drinking). Here we examined whether children with autistic spectrum disorder (ASD) are able to understand these two aspects of motor acts. Two experiments were carried out. In the first, one group of high-functioning children with ASD and one of typically developing (TD) children were presented with pictures showing hand-object interactions and asked what the individual was doing and why. In half of the “why” trials the observed grip was congruent with the function of the object (“why-use” trials), in the other half it corresponded to the grip typically used to move that object (“why-place” trials). The results showed that children with ASD have no difficulties in reporting the goals of individual motor acts. In contrast they made several errors in the why task with all errors occurring in the “why-place” trials. In the second experiment the same two groups of children saw pictures showing a hand-grip congruent with the object use, but within a context suggesting either the use of the object or its placement into a container. Here children with ASD performed as TD children, correctly indicating the agent's intention. In conclusion, our data show that understanding others' intentions can occur in two ways: by relying on motor information derived from the hand-object interaction, and by using functional information derived from the object's standard use. Children with ASD have no deficit in the second type of understanding, while they have difficulties in understanding others' intentions when they have to rely exclusively on motor cues.     

Structural in silico analysis of cross-genotype-reactivity among naturally occurring HCV NS3-1073-variants in the context of HLA-A*02:01 allele

Cellular immune response plays a central role in outcome of Hepatitis C Virus (HCV) infection. While specific T-cell responses are related to viral clearance, impaired responses can lead to chronic infection, turning HCV variability into a major obstacle for vaccine development. In a recent work, Fytili et al. (2008) studied the cross reactive potential of HCV specific CD8+ T-cells and observed a large variation in immunogenicity among 28 naturally occurring NS3(1073) variants. In this work, we intend to evaluate this immunogenic variation at molecular level, through bioinformatics approaches. The D1-EM-D2 strategy was used to build in silico MHC:peptide complexes (pMHC) of these HCV-derived peptides in the context of HLA-A*02:01 allele. The TCR-interacting surface of these complexes were evaluated using the GRASP2 program. Structural analysis indicated a sharing of topological and electrostatic features among complexes that induced strong response in vitro. Besides, complexes that induced low response presented an important positively charged spot in the center of TCR-interacting area. This spot was seen even in complexes with conservative amino acid changes and is consistent with the impairment of recognition by wild-type-specific T-cells, observed in vitro. Furthermore, the most remarkable difference in electrostatic potential was seen precisely in the only complex unable to induce in vitro stimulation. All these observations were confirmed by Principal Component Analysis (PCA) and this approach was also applied to a set of 45 non-related immunogenic viral epitopes, indicating possible new targets for cross-reactivity studies. Our results suggest structural in silico analysis of pMHC complexes as a reliable tool for vaccine development, affording to predict the impact of viral escape mutations and selection of epitopes with potential to induce cross-reactive immune responses.     

Osteoporosis treatment and fracture incidence: the ICARO longitudinal study

SUMMARY: None of the available osteoporosis therapies completely abolish the risk of fracture. Among 862 patients on treatment with antiresorptive agents (alendronate, risedronate, and raloxifene) for >1 year a fragility fracture was observed in 9.5%/year. This incidence is considerably higher than that observed in randomized clinical trials. INTRODUCTION: Available osteoporosis therapies reduced in randomized controlled trials (RCTs) the risk of fracture by 30-50%. The proportion of patients suffering from new fractures while on active treatment ("inadequate clinical treatment response" or ICR) can be derived from the data of the RCTs, where confounding factors are usually controlled by the exclusion criteria. In the retrospective part of the ICARO study we observed a 8.9% annual incidence of ICR. Here we report the results of the longitudinal part of the study. METHODS: The study includes 862 women with severe postmenopausal osteoporosis. Ninety-two of these patients (10.7%) were defined as having ICR (9.5%/year) during therapy with antiresorptive drugs (alendronate, risedronate, and raloxifene) for at least 1 year. RESULTS: The ICR patients were comparable to patients who did not sustain clinical fractures with regard to body mass index, follow-up duration, number of prevalent vertebral fractures, type of osteoporosis treatment, proportion of patients taking calcium and vitamin D supplements, and compliance with treatment. Those with ICR were significantly older (p=0.032) and more frequently had multiple vertebral deformities (p=0.013). CONCLUSIONS: The incidence of ICR during treatment with antiresorptive agents among patients with severe postmenopausal osteoporosis in a routine setting is considerably higher than that observed in randomized clinical trials.     

Bone marrow cells recruited through the neuropilin-1 receptor promote arterial formation at the sites of adult neoangiogenesis in mice

Experimental and clinical evidence indicate that bone marrow cells participate in the process of new blood vessel formation. However, the molecular mechanisms underlying their recruitment and their exact role are still elusive. Here, we show that bone marrow cells are recruited to the sites of neoangiogenesis through the neuropilin-1 (NP-1) receptor and that they are essential for the maturation of the activated endothelium and the formation of arteries in mice. By exploiting adeno-associated virus vector-mediated, long-term in vivo gene expression, we show that the 165-aa isoform of VEGF, which both activates the endothelium and recruits NP-1+ myeloid cells, is a powerful arteriogenic agent. In contrast, neither the shortest VEGF121 isoform, which does not bind NP-1 and thus does not recruit bone marrow cells, nor semaphorin 3A, which attracts cells but inhibits endothelial activation, are capable of sustaining arterial formation. Bone marrow myeloid cells are not arteriogenic per se nor are they directly incorporated in the newly formed vasculature, but they contribute to arterial formation through a paracrine effect ensuing in the activation and proliferation of tissue-resident smooth muscle cells.     

Charge binding of rhodamine derivative to OH- stabilized nanomaghemite: universal nanocarrier for construction of magnetofluorescent biosensors

Superparamagnetic nanoparticles (20-40 nm) of maghemite, γ-Fe(2)O(3), with well-defined stoichiometric structure, are synthesized by the borohydride reduction of ferric chloride at an elevated temperature (100°C) followed by thermal treatment of the reaction product. Prepared maghemite nanoparticles reveal excellent colloidal stability for a long time without the necessity for any additional surface modification. These colloidal features are due to surface stabilizing OH(-) groups, which act as charge barriers preventing a particle aggregation and enabling a reversible binding of various oppositely charged organic substances. Such binding with rhodamine B isothiocyanate results in the fluorescent magnetic nanocarrier providing, at the same time, a spacer arm for covalent immobilization of other biosubstances including enzymes. In this work, we exploit this general applicability of the developed nanocarrier for covalent immobilization of glucose oxidase. This is the first reported example of magnetically drivable fluorescent nanocatalyst. The immobilized enzyme creates a 3-5 nm thick layer on the nanoparticle surface as proved by high-resolution transmission electron microscopy. This layer corresponds to 10 enzyme molecules, which are bound to the nanoparticle surface as found by the fluorimetric determination of flavin adenine dinucleotide. The developed magnetic fluorescent nanocatalyst, showing a rate constant of 32.7s(-1) toward glucose oxidation, can be used as a biosensor in various biochemical, biotechnological, and food chemistry applications. The presence of the nanocatalyst can be simply monitored by its fluorescence; moreover, it can be easily separated from the solution by an external magnetic field and repeatedly used without a loss of catalytic efficiency.     

Study of vitamin D status of rheumatoid arthritis patients. Rationale and design of a cross-sectional study by the osteoporosis and metabolic bone diseases study group of the Italian Society of Rheumatology (SIR)

The fundamental role of Vitamin D has been long known in regulating calcium homeostasis and bone metabolism. An increased contribution of Vitamin D was recently described in association with a lower incidence of Rheumatoid Arthritis (RA). This must not be surprising, as the immunomodulating effects of Vitamin D are clear, which have been attributed protective effects in autoimmune disorders such as some chronic inflammatory bowel diseases, multiple sclerosis and type I diabetes. An interaction was suggested between Vitamin D metabolism and inflammation indexes through mediation of TNF-alpha which is also especially involved in osteoclastic resorption and therefore in bone loss processes. Some preliminary data would indicate an association between seasonal changes of Vitamin D serum levels, latitude and disease activity (DAS28) in RA patients. Consequently, the Osteoporosis and Metabolic Bone Diseases Study Group of SIR believes that there are grounded reasons for assessing the Vitamin D status of RA patients in order to investigate whether this is to be related to physiopathological and clinical aspects of disease other than those of bone involvement. Primary end point of the study will be to assess the levels of 25 OH Vitamin D in RA patients. Secondary endpoints will include correlation with dis-ease activity, densitometry values and bone turnover. The cross-sectional study will enroll patients of both sex genders, age ranging between 30 and 75 years according to the 1988 ACR criteria, onset of symptoms at least 2 years prior to study enrollment. Patients will be excluded suffering from osteo-metabolic diseases, liver and kidney insufficiency and those administered Vitamin D boli in the previous 12 months. Disease activity will be evaluated with the HAQ. Hemato-chemical tests and femoral and lumbar bone densitometry will be performed, unless recently undergone by patients. Blood levels of 25 OH C Vitamin D and PHT and of the two bone remodelling markers (bone alkaline phosphatase and serum CTX) will be measured, as well. Patient enrollment will start on February 2007 and will last 4 months. By the end of 2007 the study will be concluded and results will be published.     

MGMT expression and promoter methylation status may depend on the site of surgical sample collection within glioblastoma: a possible pitfall in stratification of patients?

We recently described a three-layer concentric model of a glioblastoma (GBM) related to a specific distribution of molecular and phenotypic characteristics driven by the intratumoral hypoxic gradient in which the cancer stem cells niche is located in the hypoxic necrotic core of the tumour. The purpose of this study was to investigate the relationship between O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation status and MGMT expression in GBM samples collected according to the three-layer concentric model. Multiple tissue samples were obtained, by means of image-guided surgery, from the three concentric layers of newly diagnosed GBM. Two samples from each layer were collected from 12 patients (total 72 samples). Immunohistochemical analysis was performed on formalin-fixed paraffin-embedded tissue samples. The methylation status of the MGMT promoter was determined by methylation-specific polymerase-chain-reaction analysis. In all tumours, MGMT protein expression decreased progressively from the inner to the outer layer, and methylation of the MGMT promoter was unrelated to tumour layer. In particular, the MGMT promoter was unmethylated in all layers in 41.7% of tumours, methylated in all layers in 25%, and variably methylated in the three layers in 33.3%. We recorded concordance between MGMT expression and MGMT promoter methylation status within the GBM in only 58.8% of the samples collected. Our data suggest that both MGMT expression and promoter methylation data may be variable throughout GBM and that they may, consequently, depend on the site of surgical sample collection, even in the same patient. However, whereas MGMT expression is pre-operatively predictable when sampling is performed according to the three-layer concentric model, MGMT promoter methylation is not. These results must be considered when sample collection is performed for assessment of MGMT data.     

Substitution of aspartic acid at β57 with alanine alters MHC class II peptide binding activity but not protein stability: HLA-DQ (α1*0201, β1*0302) and (α1*0201, β1*0303)

In class II major histocompatibility complex (MHC) proteins, residue β57 is usually aspartic acid. Alleles carrying serine, valine, or alanine at this position are strongly correlated with the development of insulin-dependent diabetes mellitus (IDDM). Aspβ57 participates in a conserved salt bridge that bridges the α and β subunits in the peptide-binding site. It has been proposed that the correlation between IDDM and MHC alleles lacking Aspβ57 may be due to an instability of the protein caused by loss of this salt bridge. Using a pair of HLA-DQ proteins (α1*0201, β1*0302) and (α1*0201, β1*0303) differing only in having aspartic acid or alanine at position β57, we show that the polymorphism does not have a significant effect on protein stability for either the empty or peptide-loaded forms. However, the circular dichroism spectra indicate that empty and peptide-loaded Alaβ57 proteins display slightly different secondary structures relative to their Aspβ57 counterparts. A set of three peptides shows different binding affinities for DQ(α1*0201, β1*0302) relative to DQ(α1*0201, β1*0303). We propose that substitution of Aspβ57 residue causes a local rearrangement within the DQ peptide-binding site that alters the peptide-binding specificity. This rearrangement may help to explain the previously observed differences in SDS stability between Asp and non-Aspβ57 DQ proteins.