INFLUENCE OF CHRONIC KIDNEY DISEASE ON THE HAEMOSTATIC PROPERTIES, THE PLATELET TRANSCRIPTOMIC AND PLASMA PROTEOMIC PROFILES OF CORONARY ARTERY DISEASE PATIENTS

BACKGROUND - Patients with CKD present a higher incidence of coronary artery disease (CAD) and increasing evidence indicates that these patients are more likely to die of cardiovascular disease than to develop kidney failure. CKD patients show a double haemostatic profile: thrombotic tendencies, but also a bleeding diathesis. Platelets and Tissue Factor (TF), the main activator of blood coagulation, play a key role in the pathogenesis and in the thrombotic complications of CAD. TF is expressed also by circulating platelets and, of interest, platelet-associated TF expression is higher in acute coronary syndrome (ACS) patients. However, there are no studies focused on platelet-associated TF expression in CAD patients with CKD. Moreover, although it is reported that platelet transcriptome may vary in pathological conditions, no information is still available on the changes that may occur in platelet transcriptome of CAD patients with CKD. Finally, patients with end-stage renal disease (ESRD) present changes in the expression of plasma proteins associated to atherosclerosis, but no data are so far available on the plasma proteomic profile of CAD patients with mild-to-moderate CKD. AIM - The aim of this project has been to further characterize the haemostatic tendencies (assessment of TF expression and of the global haemostatic function of whole blood), the platelet transcriptome and the plasma proteome of CAD patients with and without CKD. METHODS - 139 ACS patients with (n=31) and without CKD (n=108) and 217 SA patients with (n=49) and without CKD (n=168) were enrolled. The glomerular filtration rate (GFR) has been calculated with the MDRD CKD EPI Equation and CKD is defined by an estimated GFR value < 60 ml/min. Assessment of surface and intracellular platelet TF expression has been performed by whole blood flow cytometry; the global haemostatic function by thromboelastometry (ROTEM); platelet transcriptome profiles using Illumina BeadChip Human HT-12 v4 microarray; the plasma proteomic profile by the classical gel-based proteomic approach and the results confirmed by ELISA analysis. RESULTS - The percentage of TF expression on platelet surface is significantly lower in CKD patients compared to patients without CKD in resting condition (ACS: 4.07%\ub11.05 and 5.23%\ub10.82 respectively, p0,05; SA: 12.93%\ub12.73 and 16.54%\ub11.52 respectively, p>0.05). This result is also supported by the intracellular expression of platelet TF performed on a subgroup of ACS patients: intracellular TF is significantly lower in patients with CKD compared to those without CKD (19.49%\ub14.04 and 27.53%\ub15.16 respectively, p<0,001). The haemostatic function of blood, assessed by thromboelastometry, shows that, in physiological conditions, the presence of CKD exerts different effects on the global haemostatic potential in SA and ACS patients, but in the presence of a platelet inhibitor, the formation of a pure fibrin clot is similar between these two groups of patients. Moreover, there is differential gene expression among patients with and without CKD: in particular, in CKD patients, there is the over-expression of genes involved in platelet activation and in the defence against oxidative damage, but also the down-regulation of translational elongation genes that may affect the de novo protein synthesis capacity of platelets from CKD patients. The proteomic analysis shows significant differences among patients with and without CKD (both SA and ACS) in the expression of alpha-1-Microglobulin (A1M), an anti-oxidant protein, Retinol Binding Protein 4 (RBP4), involved in the early phases of inflammation and Haptoglobin (HPT), an anti-inflammatory protein: all these proteins have a positive correlation with the severity of the renal pathology. CONCLUSIONS - In conclusion, all these data shed new light on additional mechanisms involved in CKD-associated haemostatic (thrombotic and haemorrhagic) profile of CAD patients. The peculiar platelet phenotype (lower amount of TF expression), found in CKD patients, provides information on the bleeding risk due to the platelet dysfunction responsible for the haemostatic abnormalities. The evaluation of the global haemostatic capacity of whole blood has shown that ACS patients with CKD seem to have a platelet function more \u201ccompromised\u201d compared to SA patients with CKD, in terms of clotting time, that is slower in ACS patients. Furthermore, CKD patients present also a differential gene expression profile and differentially expressed proteins compared to patients without CKD: there is the concomitant presence of transcripts and proteins with a protective function (anti-inflammatory and anti-oxidant), but also with the role to promote the progression of CKD and the development of the thrombotic/haemorrhagic complications

Individual differences in responsivity to social rewards: insights from two eye-tracking tasks

Humans generally prefer social over nonsocial stimuli from an early age. Reduced preference for social rewards has been observed in individuals with autism spectrum conditions (ASC). This preference has typically been noted in separate tasks that measure orienting toward and engaging with social stimuli. In this experiment, we used two eye-tracking tasks to index both of these aspects of social preference in in 77 typical adults. We used two measures, global effect and preferential looking time. The global effect task measures saccadic deviation toward a social stimulus (related to 'orienting'), while the preferential looking task records gaze duration bias toward social stimuli (relating to 'engaging'). Social rewards were found to elicit greater saccadic deviation and greater gaze duration bias, suggesting that they have both greater salience and higher value compared to nonsocial rewards. Trait empathy was positively correlated with the measure of relative value of social rewards, but not with their salience. This study thus elucidates the relationship of empathy with social reward processing

Endothelial Dysfunction in Patients with Severe Mitral Regurgitation

Mitral valve prolapse (MVP) is the most common cause of severe mitral regurgitation. It has been reported that MVP patients-candidates for mitral valve repair (MVRep)-showed an alteration in the antioxidant defense systems as well as in the L-arginine metabolic pathway. In this study, we investigate if oxidative stress and endothelial dysfunction are an MVP consequence or driving factors. Forty-five patients undergoing MVRep were evaluated before and 6 months post surgery and compared to 29 controls. Oxidized (GSSG) and reduced (GSH) forms of glutathione, and L-arginine metabolic pathway were analyzed using liquid chromatography-tandem mass spectrometry methods while osteoprotegerin (OPG) through the ELISA kit and circulating endothelial microparticles (EMP) by flow cytometry. Six-month post surgery, in MVP patients, the GSSG/GSH ratio decreased while symmetric and asymmetric dimethylarginines levels remained comparable to the baseline. Conversely, OPG levels significantly increased when compared to their baseline. Finally, pre-MVRep EMP levels were significantly higher in patients than in controls and did not change post surgery. Overall, these results highlight that MVRep completely restores the increased oxidative stress levels, as evidenced in MVP patients. Conversely, no amelioration of endothelial dysfunction was evidenced after surgery. Thus, therapies aimed to restore a proper endothelial function before and after surgical repair could benefit MVP patients

MicroRNA-222 Regulates Melanoma Plasticity

Melanoma is one of the most aggressive and highly resistant tumors. Cell plasticity in melanoma is one of the main culprits behind its metastatic capabilities. The detailed molecular mechanisms controlling melanoma plasticity are still not completely understood. Here we combine mathematical models of phenotypic switching with experiments on IgR39 human melanoma cells to identify possible key targets to impair phenotypic switching. Our mathematical model shows that a cancer stem cell subpopulation within the tumor prevents phenotypic switching of the other cancer cells. Experiments reveal that hsa-mir-222 is a key factor enabling this process. Our results shed new light on melanoma plasticity, providing a potential target and guidance for therapeutic studies

Preparazioni piastriniche per studi di trascrittomica: caccia al leucocita

Preparazioni piastriniche per studi di trascrittomica: caccia al leucocit

The Role of Tissue Factor in Atherothrombosis and Coronary Artery Disease : Insights into Platelet Tissue Factor

The contribution of vessel wall-derived tissue factor (TF) to atherothrombosis is well established, whereas the pathophysiological relevance of the blood-borne TF is still a matter of debate, and controversies on the presence of platelet-associated TF still exist. In the past 15 years, several studies have documented the presence of TF in human platelets, the capacity of human platelets to use TF mRNA to make de novo protein synthesis, and the increase in the percentage of TF positive platelets in pathological conditions such as coronary artery disease (CAD). The exposure of vessel wall-derived TF at the site of vascular injury would play its main role in the initiation phase, whereas the blood-borne TF carried by platelets would be involved in the propagation phase of thrombus formation. More recent data indicate that megakaryocytes are committed to release into the bloodstream a well-defined number of TF-carrying platelets, which represents only a fraction of the whole platelet population. These findings are in line with the evidence that platelets are heterogeneous in their functions and only a subset of them is involved in the hemostatic process. In this review we summarize the existing knowledge on platelet associated TF and speculate on its relevance to physiology and to atherothrombosis and CAD

Emission rate of non-methane volatile organic compounds from biodegradable domestic waste

This study analyses the dynamics of emission of major non-methane volatile organic compounds from domestic waste of known composition, kept in containers for 25 days under different aeration conditions. The major non-oxy-genated volatile compounds identified were α- and β-pinene, limonene, γ-terpinene, p-cymene and dimethyldisulphide. An initial burst in the emission rates of these compounds was followed by a stationary phase with relatively low but constant emission, with non clear-cut dependence on storage conditions, namely the presence or absence of excess oxy-gen. The major oxygenated volatile compounds identified were n-butanol, acetic acid and ethyl n-butanoate. The time-emission curves of these compounds markedly varied with the specific compound considered, as well as with storage conditions. For n-butanol and ethyl n-butanoate, the emis-sion rates increased exponentially with the time of air ab-sence (argon atmosphere), whereas they remained almost nil in aerated containers throughout the tudy period. As a general trend, after the first few days of storage, the emission rates were about two times higher in absence of air than in well-aerated containers © by PSP