I SERVIZI DI INTERESSE ECONOMICO GENERALE COME OBIETTIVO DELLE POLITICHE COMUNITARIE: IL CASO DEL MERCATO DELL'ENERGIA

2004/2005XVIII Ciclo1975Versione digitalizzata della tesi di dottorato cartacea

Amotosalen/ultraviolet A pathogen inactivation technology reduces platelet activatability, induces apoptosis and accelerates clearance

Amotosalen and ultraviolet A (UVA) photochemical-based pathogen reduction using the Intercept™ Blood System (IBS) is an effective and established technology for platelet and plasma components, which is adopted in more than 40 countries worldwide. Several reports point towards a reduced platelet function after Amotosalen/UVA exposure. The study herein was undertaken to identify the mechanisms responsible for the early impairment of platelet function by the IBS. Twenty-five platelet apheresis units were collected from healthy volunteers following standard procedures and split into 2 components, 1 untreated and the other treated with Amotosalen/UVA. Platelet impedance aggregation in response to collagen and thrombin was reduced by 80% and 60%, respectively, in IBS-treated units at day 1 of storage. Glycoprotein Ib (GpIb) levels were significantly lower in IBS samples and soluble glycocalicin correspondingly augmented; furthermore, GpIbα was significantly more desialylated as shown by(ECL) binding. The pro-apoptotic Bak protein was significantly increased, as well as the MAPK p38 phosphorylation and caspase-3 cleavage. Stored IBS-treated platelets injected into immune-deficient nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice showed a faster clearance. We conclude that the IBS induces platelet p38 activation, GpIb shedding and platelet apoptosis through a caspase-dependent mechanism, thus reducing platelet function and survival. These mechanisms are of relevance in transfusion medicine, where the IBS increases patient safety at the expense of platelet function and survival

Differences in expression of DPPIV in steatotic rat liver are not related to differences in the methylation of its gene promoter

The aim of the study was to investigate the methylation status in the promoter region of Dipeptidyl peptidase-IV (Dpp4) gene, in livers from obese Zucker rats with different patterns of immunohistochemical positivity. The study focused on the genomic region of 1,000 bp, which includes the final part of 680 bp of the Dpp4 gene promoter and a small stretch of 320 bp at the beginning of the gene. The results indicate that the different immunohistochemical pattern of DPP4 observed in obese (fa/fa) and lean (fa/-) Zucker rats is not correlated to DNA methylation of its promote

Glycoprotein Ib clustering in platelets can be inhibited by alpha-linolenic acid as revealed by cryo-electron tomography

Platelet adhesion to the sub-endothelial matrix and damaged endothelium occurs through a multi-step process mediated in the initial phase by glycoprotein Ib binding to von Willebrand factor, which leads to the subsequent formation of a platelet plug. The plant-derived omega-3 fatty acid alpha-linolenic acid is an abundant alternative to fish-derived n-3 FA and has anti-inflammatory and anti-thrombotic properties. In this study, we investigated the impact of alpha-linolenic acid on human platelet binding to vWF under high-shear flow conditions (mimicking blood flow in stenosed arteries). Pre-incubation of fresh human blood from healthy donors with alpha-linolenic acid at dietary relevant concentrations reduced platelet binding and rolling on vWF-coated microchannels at a shear rate of 100 dyn/cm2. Depletion of membrane cholesterol by incubation of platelet-rich-plasma with methyl-beta cyclodextrin abrogated platelet rolling on vWF. Analysis of glycoprotein Ib by applying cryo-electron tomography to intact platelets revealed local clusters of glycoprotein Ib complexes, upon shear-force exposure, whose formation could be prevented by alpha-linolenic acid treatment. This study provides novel findings on the rapid local rearrangement of the glycoprotein Ib complexes in response to high-shear flow and highlights the mechanism of in vitro inhibition of platelet binding to and rolling on vWF by alpha-linolenic acid

Dietary alpha‐linolenic acid reduces platelet activation and collagen‐mediated cell adhesion in sickle cell disease mice

Background: Sickle cell disease (SCD) is a genetic hemoglobinopathy associated with high morbidity and mortality. The primary cause of hospitalization in SCD is vaso-occlusive crisis (VOC), mediated by alteration of red blood cells, platelets, immune cells and a pro-adhesive endothelium. Objectives: We investigated the potential therapeutic use of the plant-derived omega-3 alpha-linolenic acid (ALA) in SCD. Methods: Berkeley mice were fed a low- or high-ALA diet for 4 weeks, followed by analysis of liver fibrosis, endothelial activation, platelet activation and formation of platelet-neutrophils aggregates. Aggregation of platelets over collagen under flow after high-ALA was compared to a blocking P-selectin Fab. Results: Dietary high-ALA was able to reduce the number of sickle cells in blood smear, liver fibrosis, and the expression of adhesion molecules on the endothelium of aorta, lungs, liver and kidneys (VCAM-1, ICAM-1 and vWF). Specific parameters of platelet activation were blunted after high-ALA feeding, notably P-selectin exposure and the formation of neutrophil-platelet aggregates, along with a correspondingly reduced expression of PSGL-1 on neutrophils. By comparison, in vivo treatment of SCD mice with the anti-P-selectin Fab was able to similarly reduce the formation of neutrophil-platelet aggregates, but did not reduce GpIbα shedding nor the activation of the αIIb β3 integrin in response to thrombin. Both ALA feeding and P-selectin blocking significantly reduced collagen-mediated cell adhesion under flow. Conclusions: Dietary ALA is able to reduce the pro-inflammatory and pro-thrombotic state occurring in the SCD mouse model and may represent a novel, inexpensive and readily available therapeutic strategy for SCD

Amotosalen/ultraviolet A pathogen inactivation technology reduces platelet activatability, induces apoptosis and accelerates clearance

Amotosalen and ultraviolet A (UVA) photochemical-based pathogen reduction using the Intercept™ Blood System (IBS) is an effective and established technology for platelet and plasma components, which is adopted in more than 40 countries worldwide. Several reports point towards a reduced platelet function after Amotosalen/UVA exposure. The study herein was undertaken to identify the mechanisms responsible for the early impairment of platelet function by the IBS. Twenty-five platelet apheresis units were collected from healthy volunteers following standard procedures and split into 2 components, 1 untreated and the other treated with Amotosalen/UVA. Platelet impedance aggregation in response to collagen and thrombin was reduced by 80% and 60%, respectively, in IBS-treated units at day 1 of storage. Glycoprotein Ib (GpIb) levels were significantly lower in IBS samples and soluble glycocalicin correspondingly augmented; furthermore, GpIbα was significantly more desialylated as shown by Erythrina Cristagalli Lectin (ECL) binding. The pro-apoptotic Bak protein was significantly increased, as well as the MAPK p38 phosphorylation and caspase-3 cleavage. Stored IBS-treated platelets injected into immune-deficient nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice showed a faster clearance. We conclude that the IBS induces platelet p38 activation, GpIb shedding and platelet apoptosis through a caspase-dependent mechanism, thus reducing platelet function and survival. These mechanisms are of relevance in transfusion medicine, where the IBS increases patient safety at the expense of platelet function and survival

Whole blood omega-3 fatty acid concentrations are inversely associated with blood pressure in young, healthy adults

BACKGROUND Omega-3 fatty acids (n - 3 FA) may have blood pressure (BP)-lowering effects in untreated hypertensive and elderly patients. The effect of n - 3 FA on BP in young, healthy adults remains unknown. The Omega-3 Index reliably reflects an individuals' omega-3 status. We hypothesized that the Omega-3 Index is inversely associated with BP levels in young healthy adults. METHODS The current study (n = 2036) is a cross-sectional study investigating the baseline characteristics of a cohort, which includes healthy adults, age 25-41 years. Individuals with cardiovascular disease, known diabetes or a BMI higher than 35 kg/m were excluded. The Omega-3 Index was determined in whole blood using gas chromatography. Association with office and 24-h BP was assessed using multivariable linear regression models adjusted for potential confounders. RESULTS Median Omega-3 Index was 4.58% (interquartile range 4.08; 5.25). Compared with individuals in the lowest Omega-3 Index quartile, individuals in the highest had a SBP and DBP that was 4 and 2 mmHg lower, respectively (P < 0.01). A significant linear inverse relationship of the Omega-3 Index with 24-h and office BP was observed. Per 1-U increase in log-transformed Omega-3 Index the lowering in BP (given as multivariable adjusted β coefficients; 95% confidence interval) was -2.67 mmHg (-4.83; -0.51; P = 0.02) and -2.30 mmHg (-3.92; -0.68; P = 0.005) for 24-h SBP and DBP, respectively. CONCLUSION A higher Omega-3 Index is associated with statistically significant, clinically relevant lower SBP and DBP levels in normotensive young and healthy individuals. Diets rich in n - 3 FA may be a strategy for primary prevention of hypertension