Paul Richard Julian Ames

Background and Aims. platelet factor 4 (PF4) is a 7.8 kDa chemokine comprising 70 amino acids. Three anti-parallel β-sheets defining a hydrophobic region characterise the N-terminus; two pairs of contiguous oxidizable lysine residues defining a β-helix with amphiphilic properties characterised the carboxyl-terminus. During coagulation, the positively charged moieties of PF4 bind with high affinity to the negatively charged heparan sulphate (HS) and glycosaminoglycans (GAGs) neutralising their anticoagulant effect. Herein we detailed the amphiphilic and HS and ganglioside GM1-binding properties of PF4 and their possible modification after oxidation and nitration.Methods. charge-shift electrophoresis (CSE) (1% agarose gels (0.05 M glycine/NaOH, 0.1 M NaCl, pH 9.0) in the presence of: 1) a detergent mix of composed of neutral TritonX-100 (TX100) and anionic deoxycholate (DOC) and in the presence of 2) the cationic detergent cetyltrimethylammonium bromide (CTAB); in vitro oxidation with 1mM 4-hydroxy-2-nonenal and in vitro nitration with 60 μM peroxynitrite (ONOO-).Results. 1) PF4 shifted markedly in the presence of TX-100 plus DOC, indicating its ability to participate in the formation of mixed micelles with TX-100 and DOC compared to TX-100 alone or no detergent at all. 2) In the presence of TX-100 plus CTAB, PF4 exhibited no cathodic shift. The incorporation of Sudan Black B proved that mixed micelles of TX-100/DOC and TX-100-CTAB were formed under the conditions employed. However, the anodic shift of PF4 in the presence of DOC, with unaltered migration in the presence of CTAB are testimony to the electrostatic nature of the interaction of PF4 with DOC, with no participation of PF4 in the formation of mixed detergent micelles. 3) The migration of PF4 was shifted to the anod also in the presence of ganglioside GM1 at concentrations from 0.33 to 1.33 mg/mL, exceeding the GM1 critical micellar concentration. The formation of GM1 micelles was also documented by the SBB incorporation. GM1 binding to PF4 was dose-dependent, reaching saturation at the GM1:PF4 ratio of 1.2:1 by mass, or 23:1 on a molar basis. The formation of GM1 micelles with multiple negative charges was indispensable for shifting PF4 toward the anod, since the interaction of PF4 with the sole GM1 pentasaccharide mojety was unable to cause the same effect. 4) By the same CSE methodology in the absence of detergents, but with the addition of either HS or chondroitin sulfate (CS), PF4 shifted to the anode more markedly than in the presence of DOC and GM1; in addition, the PF4-CS complexes were highly poly-dispersed compared to the PF4-HS complexes. 5) In vitro oxidation with 1 mM 4-hydroxy-2-nonenal or nitration with 60 μM peroxynitrite (ONOO-) made PF4 undetectable in the agarose gels, likely due to aggregation/precipitation in the reaction vials.Conclusions. we document the ability of PF4 to establish electrostatic interactions with negatively charged amphiphilic molecules, such as the negatively charged surfactant DOC and ganglioside GM1, as well as polyanionic polysaccharides. This is relevant in physiological PF4 interactions with the annular lipid shells that are in contact with the hydrophobic surfaces and support the structural stability and functions of integral membrane proteins, such as HS proteoglycans expressed on endothelial cells and activated platelets, perlecan and chemokine receptor CXCR3B at the surface of endothelial cells. The destabilization of PF4 upon reaction with 4-hydroxy-2-nonenal and peroxynitrite indicates that in the course of oxidative and nitrative stress occurring in inflammation the physiologic functions of PF4 could be lost.

The use of a wide variety of antioxidants has been advocated as a means to prevent, delay the progression of, or counteract the adverse consequences of sarcopenia, such as loss of muscle strength, muscle quantity/quality, and physical performance. However, these proposals do not always appear to be supported in the literature by a thorough understanding of the contribution of redox perturbations to the pathogenesis of sarcopenia, nor of the biochemical properties, mechanism of action, pharmacokinetics, and pharmacodynamics of different antioxidants. This review discusses these aspects, aiming to provide a rationale for the selection and use of antioxidants in sarcopenia. After providing a definition of sarcopenia in the context of frailty, we distinguish between oxidative eustress as a physiological response of muscle cells to mild stimulation, such as moderate exercise, mediating their capacity for adaptation and regeneration, and oxidative distress as a pathophysiological response to muscle cell damage and death. The role of oxidative damage to biological macromolecules, both direct and mediated by advanced lipid peroxidation end products and advanced glycation/glycoxidation end products, is examined in detail. Next, we discuss antioxidant defense mechanisms, both enzymatic and non-enzymatic, including redox-sensitive gene regulatory events presided over by nuclear factor erythroid 2-related factor 2, the master regulator of enzymatic antioxidants. The review then discusses criteria for a rational classification of non-enzymatic antioxidants. This is followed by a review of some of the main radical-trapping antioxidants, both phenolic and non-phenolic, whose characteristics are compared.

The thrombotic physiopathology of antiphospholipid syndrome (APS) is complex, heterogeneous, and dynamic. While venous thromboembolism (VTE) is the most common initial presentation, arterial thrombotic events (ATE) become more frequent in advanced stages and are associated with high morbidity and mortality. Despite the use of oral anticoagulants (OACs), thrombotic APS remains associated with a high risk of recurrent thrombosis. Given their potential antithrombotic effects capable of reducing the risk of both VTE and ATE, statins have been proposed as an adjunctive therapy to OACs for patients with APS and recurrent thrombosis. However, this recommendation is primarily based on studies not specifically conducted in APS populations, with only preclinical data or evidence from retrospective observational studies available from APS patients cohorts. For these reasons, this narrative review aims to synthesise the studies evaluating the potential antithrombotic effects of statins in patients with APS, highlighting the progress made and identifying areas for future research.

The aim of this study was to evaluate the impact of methylene tetrahydrofolate reductase (MTHFR) rs1801133 (C→T667 transition) on age at first idiopathic portal vein thrombosis (PVT) and to identify clinical and/or laboratory variables influencing age at first PVT, including plasma homocysteine and the prothrombin rs1799963 PT (G→A transition at position 20210) (PT) mutation. A retrospective cross-sectional cohort, including 15 MTHFR TT, 32 MTHFR TC and 22 MTHFR CC idiopathic PVT participants contributing demographics, age at PVT, plasma concentrations of homocysteine and of natural anticoagulants. MTHFR TT carriers presented with a lower age at PVT than heterozygous or wild-type genotypes (31 ± 8 vs. 48 ± 15 vs. 52 ± 13 years, P = 0.001) and were more likely to have a plasma HC concentration above the cut-off (73.3 vs. 32 vs. 50%, P = 0.04). MTHFR TT and protein C predicted age at PVT (P < 0.0001 and P = 0.06); MTHFR TT predicted plasma homocysteine (P = 0.05). In the MTHFR TT group, plasma homocysteine inversely related to protein C (P = 0.03). Plasma homocysteine predicted the extent of PVT (P = 0.03). Compound MTHFR TT + PT GA did not lower age at first PVT compared to MTHFR TT alone (35 ± 9 vs. 30 ± 8 years). MTHFR TT is associated with a 20-year earlier PVT presentation than heterozygous and wild-type MTHFR genotypes. The inverse relation between plasma homocysteine and protein C contributes to the prematurity of PVT in the MTHFR TT group, whereas plasma homocysteine contributes to the extent of PVT. The recent exclusion of MTHFR genotyping from the thrombophilia screen needs revisiting in this setting.

Purpose: To assess age at 1(st) central retinal vein occlusion (CRVO) in carriers <= 45 years old of the methylenetetrahydrofolate reductase (MTHFR) C667T genotype compared to heterozygous and wild type, and to identify predictors of age at CRVO. Methods: Retrospective cohort study consisting of 18 MTHFR TT, 23 MTHFR TC and 28 MTHFR CC participants; information regarding age, sex, age at CRVO, history of dyslipidaemia, hypertension, smoking and plasma HC measured by immunoassay were collected. Results: Age at CRVO was lower in MTHFR TT than MTHFR TC and CC (32 +/- 6 vs 38 +/- 5 vs 37 +/- 6 years, respectively, p = 0.005); plasma HC was higher in MTHFR TT than in the other genotypes [14.4 (10.8, 19.6) vs 10.4 ((8.6,12.5) vs 8.5 ((7.5,9.8) mu mol/l, p = 0.0002). Smoking (cigarettes/day) independently predicted age at CRVO (p = 0.039) and plasma HC (p = 0.005); smoking status (yes/no) predicted ischemic CRVO (p = 0.01) that was more common in the MTHFR TT group (p = 0.006). Conclusions: Carriers of the MTHFR TT genotype <= 45 years old develop their 1(st) CRVO on average 5 years earlier than the MTHFR CC genotype; smoking contributes to the prematurity and severity of CRVO in MTHFR TT carriers.

An elderly woman with light chain myeloma presented with prolonged epistaxis and extensive cutaneous haematomas: her kappa/lambda ratio was high at 395, her coagulation screen, thrombin and reptilase times were abnormal, her FV and FX were in the low range in the absence of specific inhibitors, her Clauss fibrinogen was low at 0.95 g/l but antigenic FNG was 1.58 g/l. The patient denied treatment and died of progressive renal failure. We wish to describe the unusual association of FX and FV deficiency co-existing with an acquired dysfibrinogenaemia.

To evaluate the intima media thickness of carotid arteries (IMT) and its clinical, laboratory and treatment correlates in Behcet’s disease (BD). Systematic search of EMBASE and PubMed databases from January 2016 to October 2022; we employed random effect meta-analyses for continuous outcomes and Peto’s odds ratio for rare events. The meta-analysis included 36 case control studies: the IMT was greater in BD (n = 1103) than in controls (n = 832) (p < 0.0001) with wide heterogeneity (I² = 86.9%); a sensitivity analysis that included mean age of BD participants, gender, disease duration and activity, atherogenic index of plasma, blood pressure, C-reactive protein, ethnicity, smoking status, anti-inflammatory and immune suppressive agents, revealed that male gender, mean age of participants and azathioprine use (the latter two in inverse fashion) partly explained the heterogeneity variance (p = 0.02, p = 0.005, and p = 0.01). The IMT was greater in vascular (n = 114) than in non-vascular BD (n = 214) (p = 0.006). BD patients (n = 782) had a greater pooled prevalence of carotid plaques than controls (n = 537) (13.1% vs. 2.97%, p < 0.0001). Subclinical carotid artery atherosclerosis represents a vascular feature of BD, independently of the traditional cardiovascular risk factors. The inverse correlations between IMT, age and azathioprine use suggest that thicker carotid arteries at disease onset eventually regress with immune suppressive treatment: this assumption needs verification on adequately designed clinical trials.