Update on Inflammatory Biomarkers and Treatments in Ischemic Stroke

After an acute ischemic stroke (AIS), inflammatory processes are able to concomitantly induce both beneficial and detrimental effects. In this narrative review, we updated evidence on the inflammatory pathways and mediators that are investigated as promising therapeutic targets. We searched for papers on PubMed and MEDLINE up to August 2016. The terms searched alone or in combination were: ischemic stroke, inflammation, oxidative stress, ischemia reperfusion, innate immunity, adaptive immunity, autoimmunity. Inflammation in AIS is characterized by a storm of cytokines, chemokines, and Damage-Associated Molecular Patterns (DAMPs) released by several cells contributing to exacerbate the tissue injury both in the acute and reparative phases. Interestingly, many biomarkers have been studied, but none of these reflected the complexity of systemic immune response. Reperfusion therapies showed a good efficacy in the recovery after an AIS. New therapies appear promising both in pre-clinical and clinical studies, but still need more detailed studies to be translated in the ordinary clinical practice. In spite of clinical progresses, no beneficial long-term interventions targeting inflammation are currently available. Our knowledge about cells, biomarkers, and inflammatory markers is growing and is hoped to better evaluate the impact of new treatments, such as monoclonal antibodies and cell-based therapies.

Pre-hospital alarm activation for STEMI patients undergoing primary percutaneous coronary intervention in the era of transradial procedures

BACKGROUND

Transradial access (TRA) improves outcome compared with trans-femoral access for the management of patients with acute coronary syndromes. In this setting, it is unknown whether the activation of a pre-hospital alarm system (PHAS) confers additional benefit for the prognosis of patients with ST-segment elevation myocardial infarction (STEMI).

MATERIALS AND METHODS

We retrospectively analyzed a cohort of patients with a first STEMI who underwent a primary percutaneous coronary intervention (PPCI) at a single center within a prospective cohort of acute coronary syndrome patients (SPUM-ACS). TRA was used in 85% of patients. We assessed how PHAS (n=165) vs. no-PHAS (n=166) activation was associated with the composite outcome of all-cause mortality and recurrence of myocardial infarction (MI) at 1-year follow-up. As secondary outcomes, the individual clinical endpoints were separately assessed for association.

RESULTS

Compared with no-PHAS patients, patients in the PHAS group were predominantly women, and presented more frequently with dyslipidemia and cardiac arrest. A significant reduction in the composite outcome of all-cause mortality and recurrent MI at 1-year was observed in the PHAS group, compared with no-PHAS (3.6% vs. 8.5%, p=0.027). When adjusted for age, sex and resuscitation status, PHAS activation remained associated with decreased all-cause mortality and recurrent MI (HR: 0.36 [95% CI: 0.13-0.95]; p=0.040).

CONCLUSIONS

This study suggests that the benefit of PHAS activation in STEMI patients undergoing PPCI persists also in the era of TRA.

Intraplaque Expression of C-Reactive Protein Predicts Cardiovascular Events in Patients with Severe Atherosclerotic Carotid Artery Stenosis

Serum c-reactive protein (CRP) was suggested for the assessment of intermediate cardiovascular (CV) risk. Here, systemic or intraplaque CRP levels were investigated as predictors of major adverse cardiovascular events (MACEs) in patients with severe carotid stenosis. CRP levels were assessed in the serum and within different portions (upstream and downstream) of carotid plaques of 217 patients undergoing endarterectomy. The association between CRP and intraplaque lipids, collagen, neutrophils, smooth muscle cells (SMC), and macrophage subsets was determined. No correlation between serum CRP and intraplaque biomarkers was observed. In upstream portions, CRP content was directly correlated with intraplaque neutrophils, total macrophages, and M1 macrophages and inversely correlated with SMC content. In downstream portions, intraplaque CRP correlated with M1 and M2 macrophages. According to the cut-off point (CRP > 2.9%) identified by ROC analysis in upstream portions, Kaplan-Meier analysis showed that patients with high CRP levels had a greater rate of MACEs. This risk of MACEs increased independently of age, male gender, serum CRP, and statin use. In conclusion, in patients with severe carotid artery stenosis, high CRP levels within upstream portions of carotid plaques directly and positively correlate with intraplaque inflammatory cells and predict MACEs at an 18-month follow-up period.

Anti-ApoA-1 IgG serum levels predict worse poststroke outcomes

BACKGROUND

Autoantibodies to apolipoprotein A-1 (anti-ApoA-1 IgG) were shown to predict major adverse cardiovascular events and promote atherogenesis. However, their potential relationship with clinical disability and ischaemic lesion volume after acute ischaemic stroke (AIS) remains unexplored.

MATERIALS AND METHODS

We included n = 76 patients admitted for AIS and we investigated whether baseline serum anti-ApoA-1 IgG levels could predict (i) AIS-induced clinical disability [assessed by the modified Rankin Scale (mRS)], and (ii) AIS-related ischaemic lesion volume [assessed by Computed Tomography (CT)]. We also evaluated the possible pro-apoptotic and pro-necrotic effects of anti-ApoA-1 IgG on human astrocytoma cell line (U251) using flow cytometry.

RESULTS

High levels of anti-ApoA-1 IgG were retrieved in 15·8% (12/76) of patients. Increased baseline levels of anti-ApoA-1 IgG were independently correlated with worse mRS [β = 0·364; P = 0·002; adjusted odds ratio (OR): 1·05 (95% CI 1·01-1·09); P = 0·017] and CT-assessed ischaemic lesion volume [β = 0·333; P < 0·001; adjusted OR: 1·06 (95% CI 1·01-1·12); P = 0·048] at 3 months. No difference in baseline clinical, biochemical and radiological characteristics was observed between patients with high vs. low levels of anti-ApoA-1 IgG. Incubating human astrocytoma cells with anti-ApoA-1 IgG dose dependently induced necrosis and apoptosis of U251 cells in vitro.

CONCLUSION

Anti-ApoA-1 IgG serum levels at AIS onset are associated with poorer clinical recovery and worse brain lesion volume 3 months after AIS. These observations could be partly explained by the deleterious effect of anti-ApoA-1 IgG on human brain cell survival in vitro and may have clinical implication in the prediction of poor outcome in AIS.

Treatment with the GPR55 antagonist CID16020046 increases neutrophil activation in mouse atherogenesis

Endocannabinoids modulate atherogenesis by triggering different receptors. Recently, orphan G protein-coupled receptors (GPRs) were suggested to be activated by endocannabinoids, possibly regulating vasorelaxation. Here, we investigated whether GPR55 antagonism with CID16020046 would impact on atherosclerotic size and inflammation in two mouse models of early and more advanced atherogenesis. Eleven-week old ApoE^-/- mice were fed either a normal diet ([ND] for 16 weeks) or a high-cholesterol diet ([HD] for 11 weeks), resulting in different degrees of hypercholesterolaemia and size of atherosclerosis. CID16020046 (0.5 mg/kg) or vehicle were intraperitoneally administrated five times per week in the last three weeks before euthanasia. Treatment with CID1602004 was well-tolerated, but failed to affect atherosclerotic plaque and necrotic core size, fibrous cap thickness, macrophage and smooth muscle cell content as well as Th cell polarisation. In ND mice, treatment with CID1602004 was associated with increased chemokine production, neutrophil and MMP-9 intraplaque content as well as reduced collagen as compared to vehicle-treated animals. In HD mice, CID1602004 increased intraplaque MMP-9 and abrogated collagen content without affecting neutrophils. In vitro, serum from CID1602004-treated ND mice increased mouse neutrophil chemotaxis towards CXCL2 as compared to serum from vehicle-treated animals. CID1602004 dose-dependently induced neutrophil degranulation that was reverted by co-incubation with the GPR55 agonist Abn-CBD. In supernatants from degranulation experiments, increased levels of the endocannabinoid and putative GPR55 ligand anandamide (AEA) were found, suggesting its possible autocrine control of neutrophil activity. These results indicate that GPR55 is critical for the negative control of neutrophil activation in different phases of atherogenesis.

Biophysical aspects and novel treatments of atrial fibrillation

INTRODUCTION

Atrial fibrillation (AF) is a cardiac arrhythmia caused by various mechanisms, such as multiple re-entering wavelets, high frequency activity, and rotor sources.

EVIDENCE ACQUISITION

This narrative review was based on papers found on PubMed and MEDLINE up to May 2016. The search terms were "atrial fibrillation" in combination with "catheter ablation, pathophysiology, antiarrhythmic drugs".

EVIDENCE SYNTHESIS

Antiarrhythmic drugs are the cornerstone of therapy in AF, but their efficacy and safety might have to be improved. In case of failure of pharmacologic therapies, other treatments can be considered. A better understanding of the important role of the pulmonary veins has led to new approaches, such as ablation procedures, which were initially only surgical, while percutaneous options were later added. However, these strategies may present various technical complications also when performed by skilled operators. A promising field of investigation is the genetics of AF, as highlighted by studies on the role of micro-RNA.

CONCLUSIONS

Relevant improvement on the knowledge of the electrophysiological basis of genesis and maintenance of AF has been done in order to treat a very common arrhythmia, but further studies, as those in the genetics field, can open new challenging therapeutic horizons.

Anti-apolipoprotein A-1 auto-antibodies as active modulators of atherothrombosis

Humoral autoimmune-mediated inflammation plays a role in atherogenesis, and potentially in arterial thrombosis. Anti-apolipoprotein A-1 (apoA-1) IgG have been reported to represent emergent mediators of atherogenesis through Toll-like receptors (TLR) 2, 4 and CD14 signalling. We investigated the role of anti-apoA-1 IgG on tissue factor (TF) expression and activation, a key coagulation regulator underlying atherothrombosis. Atherothrombosis features were determined by immunohistochemical TF staining of human carotid biopsies derived from patients with severe carotid stenosis undergoing elective surgery (n=176), and on aortic roots of different genetic backgrounds mice (ApoE-/-; TLR2-/-ApoE-/- and TLR4-/-ApoE-/-) exposed to passive immunisation with anti-apoA-1 IgG. Human serum levels of anti-apoA-1 IgG were measured by ELISA. In vitro, on human-monocyte-derived-macrophages (HMDM) the anti-apoA-1 IgG increased TF expression and activity were analysed by FACS and chromogenic assays in presence of different pharmacological inhibitors. Human serum anti-apoA-1 IgG levels significantly correlated to intraplaque TF expression in carotid biopsies (r=0.31, p<0.001), which was predictive of clinically symptomatic lesions. On HMDM, anti-apoA-1 IgG induced a TLR2, 4 and CD14-dependent increase in TF expression and activity, involving NF-kappaB and a c-Jun N-terminal kinase-dependent AP-1 transcription factors. In ApoE-/- mice, anti-apoA-1 IgG passive immunisation significantly enhanced intraplaque TF expression when compared to control IgG. This effect was lost in both TLR2-/-ApoE-/- and TLR4-/-ApoE-/- mice. These results demonstrate that anti-apoA-1 IgG are associated with TF expression in human atherosclerotic plaques, induce TF expression in vitro and in vivo through TLR2 and 4 signalling, supporting a possible causal relationship between anti-apoA-1 IgG and atherothrombosis.

Treatment with anti-RANKL antibody reduces infarct size and attenuates dysfunction impacting on neutrophil-mediated injury

Selective pharmacological treatments targeting reperfusion injury produced modest protective effects and might be associated with immunosuppression. In order to identify novel and better-tolerated approaches, we focused on the neutralization of receptor activator of nuclear factor kappa-B ligand [RANKL], a cytokine recently shown to activate inflammatory cells (i.e. neutrophils) orchestrating post-infarction injury and repair. Myocardial ischemia (60min) and reperfusion injury was surgically induced in C57Bl/6 mice. In hearts and serum, RANKL was early upregulated during reperfusion. A "one-shot" injection with neutralizing anti-RANKL IgG during ischemia ameliorated myocardial infarct size and function, but not adverse remodeling (determined by Magnetic Resonance Imaging [MRI]) as compared to Vehicle or control IgG. These beneficial effects were accompanied in vivo by reduction in cardiac neutrophil infiltration, reactive oxygen species (ROS) and MMP-9 release. Anti-RANKL IgG treatment suppressed sudden peak of neutrophil granule products in mouse serum early after reperfusion onset. In vitro, RANK mRNA expression was detected in isolated mouse neutrophils. Co-incubation with neutralizing anti-RANKL IgG abrogated RANKL-induced mouse neutrophil degranulation and migration, suggesting a critical role of RANKL in neutrophil-mediated injury. Conversely, anti-RANKL IgG did not affect salvage pathways in cardiac cells (i.e. ERK p42/p44, Akt and STAT-3) or macrophage cardiac infiltration. Finally, treatment with anti-RANKL IgG showed no effect on B and T lymphocyte polarization (in serum, spleen and infarcted myocardium) and circulating chemokines as compared with Vehicle or control IgG. In conclusion, acute treatment with anti-RANKL IgG improved cardiac infarct size and function by potentially impacting on neutrophil-mediated injury and repair.

Update on cardiotoxicity of anti-cancer treatments

BACKGROUND AND AIMS

Anti-cancer treatments markedly improved the prognosis of patients, but unfortunately might be hampered by cardiotoxicity. Both symptomatic and asymptomatic clinical forms of heart failure have been reported, which may be reversible or irreversible. The aim of this review is to provide an overview of the antineoplastic agents associated with cardiac toxicity and of the available diagnostic techniques.

METHODS AND METHODS

This narrative review is based on material from MEDLINE and PUBMED up to November 2015. We looked at the terms antineoplastic drugs and cardiac toxicity in combination with echocardiography, troponins, cardiac magnetic resonance, and positron emission tomography.

RESULTS

Anthracyclines, monoclonal antibodies, fluoropyrimidines, taxanes, alkylating agents, vinka alkaloids were reported to induce different clinical manifestations of cardioxicity. Chest radiotherapy is also associated with various forms of cardiac damage, which are indistinguishable from those found in patients with heart disease of other aetiologies and that may even appear several years after administration. Among diagnostic techniques, echocardiography is a noninvasive, cost-effective, and widely available imaging tool. Nuclear imaging and cardiac magnetic resonance may be used but are not so widely available and are more difficult to perform. Finally, some biomarkers, such as troponins, may be used to evaluate cardiac damage, but establishing the optimal timing of troponin assessment remains unclear and defining the cut-off point for positivity is still an important goal.

CONCLUSIONS

Cardiotoxicity of anti-cancer treatments is associated with development of heart failure. Novel diagnostic tools might be relevant to early recognize irreversible forms cardiac diseases.

Prognostic value of PCSK9 levels in patients with acute coronary syndromes

AIMS

Proprotein convertase subtilisin kexin 9 (PCSK9) is an emerging target for the treatment of hypercholesterolaemia, but the clinical utility of PCSK9 levels to guide treatment is unknown. We aimed to prospectively assess the prognostic value of plasma PCSK9 levels in patients with acute coronary syndromes (ACS).

METHODS AND RESULTS

Plasma PCSK9 levels were measured in 2030 ACS patients undergoing coronary angiography in a Swiss prospective cohort. At 1 year, the association between PCSK9 tertiles and all-cause death was assessed adjusting for the Global Registry of Acute Coronary Events (GRACE) variables, as well as the achievement of LDL cholesterol targets of <1.8 mmol/L. Patients with higher PCSK9 levels at angiography were more likely to have clinical familial hypercholesterolaemia (rate ratio, RR 1.21, 95% confidence interval, CI 1.09-1.53), be treated with lipid-lowering therapy (RR 1.46, 95% CI 1.30-1.63), present with longer time interval of chest pain (RR 1.29, 95% CI 1.09-1.53) and higher C-reactive protein levels (RR 1.22, 95% CI 1.16-1.30). PCSK9 increased 12-24 h after ACS (374 ± 149 vs. 323 ± 134 ng/mL, P < 0.001). At 1 year follow-up, HRs for upper vs. lower PCSK9-level tertiles were 1.13 (95% CI 0.69-1.85) for all-cause death and remained similar after adjustment for the GRACE score. Patients with higher PCSK9 levels were less likely to reach the recommended LDL cholesterol targets (RR 0.81, 95% CI 0.66-0.99).

CONCLUSION

In ACS patients, high initial PCSK9 plasma levels were associated with inflammation in the acute phase and hypercholesterolaemia, but did not predict mortality at 1 year.

The role of adipocytokines in atherogenesis and atheroprogression

Research investigations on adipose tissue were focused for several decades on its "storage" function. Emerging evidence unveiled adipose tissue as an endocrine organ releasing a several mediators termed as adipokines. Adipokine-mediated functions include both physiological and pathophysiological roles such as regulation of energy metabolism, immune response and vascular homeostasis, as well as inflammatory and metabolic diseases (i.e. atherogenesis, diabetes and obesity clustered in the concept of metabolic syndrome). A dysregulation of adipokine levels has been also suggested as a potential common mechanism underlying these disorders. For instance, an unbalance between pro- and anti-inflammatory adipokines was positively associated with traditional risk factors (dyslipidaemia, hypertension, insulin resistance) in obesity, diabetes and atherogenesis. Adipokine-mediated activities particularly affected endothelial dysfunction/activation and intraplaque inflammation/vulnerability. The purpose of this narrative review is to provide an overview on the role of adipokines in atherogenesis. Evidence from basic research studies about adipokine-induced regulation of vascular and immune cell subsets will be discussed. Finally, conflicting results from clinical trials we be reported, with an attempt to better understand the reason why promising basic research results did not allow a speedy "into human" translation for clinical management of atherogenesis.

Update on the role of neutrophils in atherosclerotic plaque vulnerability

Atherosclerosis is the main pathophysiological process underlying acute cardiovascular diseases. Life-threatening conditions, such as myocardial infarction and ischemic stroke, are provoked by the sudden rupture of vulnerable atherosclerotic plaques, characterized by thin, highly inflamed and collagen-poor fibrous cap. Whereas both innate and adaptive inflammation progressively emerged as driving force of this processes, less is known about the involvement of neutrophils (PMNs). Advances in laboratory techniques during the last two decades disclosed that PMNs play a crucial role in promoting plaque vulnerability by the release of different enzymes, such as gelatinases (matrix metalloproteinases) collagenases, elastase and myeloperoxidase. Accordingly, circulating levels of PMNs and their products have been investigated as potential markers of plaque instability in both primary and secondary prevention on cardiovascular diseases. In addition, the development of different classes of drugs targeting PMNs activation is emerging as an interesting field of research. This narrative review will provide an update on the role of PMNs in promoting plaque vulnerability also discussing the potential effects of therapeutic strategies targeting PMN on plaque vulnerability.

Leptin/adiponectin ratio predicts poststroke neurological outcome

BACKGROUND AND AIMS

Different adipokines have been associated with atherosclerotic plaque rupture and cardiovascular events, such as acute ischaemic stroke (AIS). However, the potential role of these molecules in postischaemic brain injury remains largely unknown.

METHODS AND METHODS

We performed a substudy analysis on nonobese patients with first atherothrombotic stroke (n = 35) from a recently published prospective cohort. Primary endpoint was to investigate the predictive value of serum leptin/adiponectin ratio on neurological recovery at 90 days after AIS. The secondary endpoint was the predictive value of serum adipokine levels of clinical and radiological outcomes at a shorter follow-up (at days 1 and 7 after AIS). The radiological evaluation included ischaemic lesion volume and haemorrhagic transformation (HT). The clinical examination was based on National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS).

RESULTS

At day 1 after AIS, serum leptin and leptin/adiponectin ratio were increased and inversely correlated with both radiological and clinical parameters at all follow-up time points. Once identified the best cut-off points by receiver operating characteristic (ROC) analysis, risk analysis showed that higher circulating leptin improved neurological recovery at day 90. In addition, leptin/adiponectin ratio maintained statistical significance after adjustment for age, gender and thrombolysis, also predicting the occurrence of HT in the first 7 days after AIS (adjusted OR 0·15 [95% CI 0·03-0·83); P = 0·030]).

CONCLUSIONS

Higher leptin/adiponectin ratio at day 1 predicted better neurological outcomes in patients with atherothrombotic AIS and might be potentially useful as a prognostic biomarker of the disease.

Pathophysiology and Treatments of Oxidative Injury in Ischemic Stroke: Focus on the Phagocytic NADPH Oxidase 2

SIGNIFICANCE

Phagocytes play a key role in promoting the oxidative stress after ischemic stroke occurrence. The phagocytic NADPH oxidase (NOX) 2 is a membrane-bound enzyme complex involved in the antimicrobial respiratory burst and free radical production in these cells.

RECENT ADVANCES

Different oxidants have been shown to induce opposite effects on neuronal homeostasis after a stroke. However, several experimental models support the detrimental effects of NOX activity (especially the phagocytic isoform) on brain recovery after stroke. Therapeutic strategies selectively targeting the neurotoxic ROS and increasing neuroprotective oxidants have recently produced promising results.

CRITICAL ISSUES

NOX2 might promote carotid plaque rupture and stroke occurrence. In addition, NOX2-derived reactive oxygen species (ROS) released by resident and recruited phagocytes enhance cerebral ischemic injury, activating the inflammatory apoptotic pathways. The aim of this review is to update evidence on phagocyte-related oxidative stress, focusing on the role of NOX2 as a potential therapeutic target to reduce ROS-related cerebral injury after stroke.

FUTURE DIRECTIONS

Radical scavenger compounds (such as Ebselen and Edaravone) are under clinical investigation as a therapeutic approach against stroke. On the other hand, NOX inhibition might represent a promising strategy to prevent the stroke-related injury. Although selective NOX inhibitors are not yet available, nonselective compounds (such as apocynin and fasudil) provided encouraging results in preclinical studies. Whereas additional studies are needed to better evaluate this therapeutic potential in human beings, the development of specific NOX inhibitors (such as monoclonal antibodies, small-molecule inhibitors, or aptamers) might further improve brain recovery after stroke.

Cannabinoid receptor type 2 activation in atherosclerosis and acute cardiovascular diseases

In the last decades, the cannabinoid system (comprising synthetic and endogenous cannabinoid agonists and antagonists, their receptors and degrading enzymes) has been shown to induce potent immunomodulatory activities in atherogenesis and acute ischemic complications. Different from the other cannabinoid receptors in which controversial results are reported, the selective activation of the cannabinoid receptor type 2 (CB2) has been shown to play antiinflammatory and protective actions within atherosclerotic vessels and downstream ischemic peripheral organs. CB2 is a transmembrane receptor that triggers protective intracellular pathways in cardiac, immune and vascular cells in both human and animal models of atherosclerosis. Considering basic research data, medications activating CB2 function in the circulation or peripheral target organs might be a promising approach against atherogenesis. This review updates evidence from preclinical studies on different CB2-triggered pathways in atherosclerosis and acute ischemic events.

Serum osteopontin levels are upregulated and predict disability after an ischaemic stroke

BACKGROUND

After an acute ischaemic stroke (AIS), several inflammatory biomarkers have been investigated, but their predictive role on functional recovery remains to be validated. Here, we investigated the prognostic relevance of biomarkers related to atherosclerotic plaque calcification, such as osteopontin (OPN), osteoprotegerin (OPG) and the receptor activator of nuclear factor kappa-B ligand (RANKL) in a cohort of patients with AIS (n = 90) during 90-day follow-up.

MATERIALS AND METHODS

Radiological and clinical examinations as well as blood sampling were performed at admission and at days 1, 7 and 90 from the event. Validated scores [such as modified Rankin scale (mRS) and the National Institutes of Health Stroke Scale (NIHSS)] were used to assess poststroke outcome. Serum levels of OPN, OPG and RANKL were measured by colorimetric enzyme-linked immunosorbent assay (ELISA).

RESULTS

When compared to the admission, OPN serum levels increased at day 7. Serum OPN levels at this time point were positively correlated with both ischaemic lesion volume and NIHSS at days 7 and 90. A cut-off of 30.53 ng/mL was identified for serum OPN by receiver operating characteristic (ROC) curve analysis. Adjusted logistic regression showed that serum OPN levels at day 7 predicted worse mRS at day 90 [OR 4.13 (95% CI 1.64-10.36); P = 0.002] and NIHSS [1.49 (95% CI 1.16-1.99); P = 0.007], independently of age, gender, hypertension and thrombolysis.

CONCLUSIONS

Serum levels of OPN, but not OPG and RANKL, peaked at day 7 after AIS and predicted worse neurological scores. Therefore, OPN might have a pathophysiological and clinical relevance after AIS.

Treatment with KLEPTOSE® CRYSMEB reduces mouse atherogenesis by impacting on lipid profile and Th1 lymphocyte response

The ability of pharmacological agents to target both "classical" risk factors and inflammation may be key for successful outcomes in the prevention and treatment of atherogenesis. Among the promising drugs interfering with cholesterol metabolism, we investigated whether methyl beta-cyclodextrin (KLEPTOSE® CRYSMEB) could positively impact on atherogenesis, lipid profile and atherosclerotic plaque inflammation in ApoE-/- mice. Eleven-week old ApoE-/- mice were fed either a normal diet (N.D.) or a high-cholesterol diet (H.D.), resulting in different levels of hypercholesterolemia. KLEPTOSE® CRYSMEB (40mg/kg) or vehicle was intraperitoneally administrated 3 times per week in the last 16weeks before euthanasia in mice under N.D. and in the last 11weeks under H.D. Treatment with KLEPTOSE® CRYSMEB reduced triglyceride serum levels in both atherogenesis mouse models. In H.D. mice, treatment with KLEPTOSE® CRYSMEB increased HDL-cholesterol levels and reduced free fatty acids and spleen weight. In both mouse models, treatment with KLEPTOSE® CRYSMEB reduced atherosclerotic plaque size in thoraco-abdominal aortas and intraplaque T lymphocyte content, but did not induce relevant improvements in other histological parameters of vulnerability (macrophage, neutrophil, MMP-9 and collagen content). Conversely and more markedly in H.D. mice, treatment with KLEPTOSE® CRYSMEB was associated with a reduction in genetic markers of Th1-mediated immune response. In vitro, KLEPTOSE® CRYSMEB dose-dependently abrogated Th1 proliferation and IFNγ release. In conclusion, treatment with KLEPTOSE® CRYSMEB reduced atherosclerotic plaque size by improving triglyceride serum levels and Th1-mediated response. These results indicate this drug as a potential tool for blocking atheroprogression associated with different severity degrees of hypercholesterolemia.

Treatment with sulphated galactan inhibits macrophage chemotaxis and reduces intraplaque macrophage content in atherosclerotic mice

Experimental data from animal models and clinical studies support connections between the haemostasis and inflammation in atherogenesis. These interfaces among inflammation and thrombogenesis have been suggested as targets for pharmacological intervention to reduce disease progression. We hypothesize that the recently discovered antithrombotic drug Sulphated Galactan (SG) (isolated from the red marine alga Acanthophora muscoides) might reduce atherosclerotic plaque vulnerability and inflammatory gene expression in 10-week aged apolipoprotein E deficient (ApoE-/-) mice under high-cholesterol diet for additional 11weeks. Then, the underlying cellular mechanisms were investigated in vitro. SG (10mg/kg) or Vehicle was subcutaneously injected from week 6 until week 11 of the diet. Treatment with SG reduced intraplaque macrophage and Tissue Factor (TF) content as compared to Vehicle-treated animals. Intraplaque TF co-localized and positively correlated with macrophage rich-areas. No changes on atherosclerotic plaque size, and other intraplaque features of vulnerability (such as lipid, neutrophil, MMP-9 and collagen contents) were observed. Moreover, mRNA expression of MMPs, chemokines and genetic markers of Th1/2/reg/17 lymphocyte polarization within mouse aortic arches and spleens was not affected by SG treatment. In vitro, treatment with SG dose-dependently reduced macrophage chemotaxis without affecting TF production. Overall, the chronic SG treatment was well tolerated. In conclusion, our results indicate that SG treatment reduced intraplaque macrophage content (by impacting on cell recruitment) and, concomitantly, intraplaque TF content of potential macrophage origin in atherosclerotic mice.