Atherosclerotic plaque vulnerability is increased in mouse model of lupus

Autoimmune diseases and atherosclerotic cardiovascular disease

Autoimmune diseases are associated with a dramatically increased risk of atherosclerotic cardiovascular disease and its clinical manifestations. The increased risk is consistent with the notion that atherogenesis is modulated by both protective and disease-promoting immune mechanisms. Notably, traditional cardiovascular risk factors such as dyslipidaemia and hypertension alone do not explain the increased risk of cardiovascular disease associated with autoimmune diseases. Several mechanisms have been implicated in mediating the autoimmunity-associated cardiovascular risk, either directly or by modulating the effect of other risk factors in a complex interplay. Aberrant leukocyte function and pro-inflammatory cytokines are central to both disease entities, resulting in vascular dysfunction, impaired resolution of inflammation and promotion of chronic inflammation. Similarly, loss of tolerance to self-antigens and the generation of autoantibodies are key features of autoimmunity but are also implicated in the maladaptive inflammatory response during atherosclerotic cardiovascular disease. Therefore, immunomodulatory therapies are potential efficacious interventions to directly reduce the risk of cardiovascular disease, and biomarkers of autoimmune disease activity could be relevant tools to stratify patients with autoimmunity according to their cardiovascular risk. In this Review, we discuss the pathophysiological aspects of the increased cardiovascular risk associated with autoimmunity and highlight the many open questions that need to be answered to develop novel therapies that specifically address this unmet clinical need.

Accelerated atherosclerosis in beta-thalassemia

Children with beta-thalassemia (BT) present with an increase in carotid intima-medial thickness, an early sign suggestive of premature atherosclerosis. However, it is unknown if there is a direct relationship between BT and atherosclerotic disease. To evaluate this, wild-type (WT, littermates) and BT (Hbbth3/+) mice, both male and female, were placed on a 3-mo high-fat diet with low-density lipoprotein receptor suppression via overexpression of proprotein convertase subtilisin/kexin type 9 (PCSK9) gain-of-function mutation (D377Y). Mechanistically, we hypothesize that heme-mediated oxidative stress creates a proatherogenic environment in BT because BT is a hemolytic anemia that has increased free heme and exhausted hemopexin, heme's endogenous scavenger, in the vasculature. We evaluated the effect of hemopexin (HPX) therapy, mediated via an adeno-associated virus, to the progression of atherosclerosis in BT and a phenylhydrazine-induced model of intravascular hemolysis. In addition, we evaluated the effect of deferiprone (DFP)-mediated iron chelation in the progression of atherosclerosis in BT mice. Aortic en face and aortic root lesion area analysis revealed elevated plaque accumulation in both male and female BT mice compared with WT mice. Hemopexin therapy was able to decrease plaque accumulation in both BT mice and mice on our phenylhydrazine (PHZ)-induced model of hemolysis. DFP decreased atherosclerosis in BT mice but did not provide an additive benefit to HPX therapy. Our data demonstrate for the first time that the underlying pathophysiology of BT leads to accelerated atherosclerosis and shows that heme contributes to atherosclerotic plaque development in BT.NEW & NOTEWORTHY This work definitively shows for the first time that beta-thalassemia leads to accelerated atherosclerosis. We demonstrated that intravascular hemolysis is a prominent feature in beta-thalassemia and the resulting increases in free heme are mechanistically relevant. Adeno-associated virus (AAV)-hemopexin therapy led to decreased free heme and atherosclerotic plaque area in both beta-thalassemia and phenylhydrazine-treated mice. Deferiprone-mediated iron chelation led to deceased plaque accumulation in beta-thalassemia mice but provided no additive benefit to hemopexin therapy.

Novel Biomarkers and Imaging Indices for the "Vulnerable Patient" with Carotid Stenosis: A Single-Center Study

BACKGROUND

We investigated the relationship of matrix metalloproteinases (MMPs), cardio-ankle vascular index (CAVI), and Gray-Scale Median (GSM) score with the severity and vulnerability of carotid atherosclerosis and major adverse cardiovascular events (MACE) during follow-up of carotid artery revascularization.

METHODS

We enrolled 262 patients undergoing carotid revascularization therapy (GRT), 109 asymptomatic patients with low-grade carotid stenosis (40-70%) receiving conservative treatment (GCT), and 92 age- and sex-matched control subjects without carotid atherosclerosis (GCO). All participants underwent carotid ultrasound and we assessed at baseline clinical parameters, metabolic profile, CAVI, GSM, and circulating levels of hsCRP, MMP-3,-7,-9, and TIMP-1.

RESULTS

Both GRT and GCT presented with elevated CAVI, MMPs, and TIMP-1 levels compared to GCO (p < 0.001). The escalation highly correlated to the presence of symptoms or paralleled the degree of carotid stenosis (p < 0.001). During follow-up (mean duration: 55 months), 51 GRT patients experienced MACE unrelated to the revascularization procedure. Within GRT, diabetes (HR: 2.07; CI: 1.55-2.78, p < 0.001), smoking (HR: 1.67; CI: 1.35-1.95, p < 0.001), high CAVI (HR: 1.22; CI: 1.09-1.43, p = 0.023) and MMP-9 (HR: 1.44; CI: 1.29-2.15, p = 0.005), and low GSM (HR: 1.40; CI: 1.16-2.12, p = 0.002) independently predicted MACE occurrences, despite the optimum medical therapy.

CONCLUSIONS

Novel imaging and biochemical biomarkers were positively associated with atherosclerosis severity, while CAVI, MMP-9, and low GSM showed a positive, independent relationship with MACE after carotid revascularization, describing "vulnerable patients".

Jieduquyuziyin prescription alleviates SLE complicated by atherosclerosis via promoting cholesterol efflux and suppressing TLR9/MyD88 activation

ETHNOPHARMACOLOGICAL RELEVANCE

Jieduquyuziyin prescription (JP), as a traditional Chinese medicine formula, is extensively applied to treat systemic lupus erythematosus (SLE). Its prescription is based on clinical practice and an evidence-based application of traditional medicines. It is approved by use in Chinese hospitals as a clinical prescription that can be directly used.

AIM OF THE STUDY

The study aims to elucidate JP's efficacy on lupus-like disease combined with atherosclerosis and to explore its mechanism.

MATERIALS AND METHODS

To conduct in vivo experiments, we established a model of lupus-like disease with atherosclerosis in ApoE^-/- mice fed a high-fat diet and injected intraperitoneally with pristane. In addition, oxidized low-density lipoprotein (ox-LDL) and a TLR9 agonist (CpG-ODN2395) were utilized to examine the mechanism of JP on SLE combined with AS in RAW264.7 macrophages in vitro.

RESULTS

Results indicated that JP reduced hair loss and levels of the spleen index, maintained stable body weight, alleviated kidney damage in mice, and reduced the expression levels of urinary protein, autoantibodies, and inflammatory factors in serum. Furthermore, JP is effective at alleviating the lupus-like symptoms observed in mice. In mice, JP inhibited aortic plaque deposition, stimulated lipid metabolism, and increased the expression of genes that regulate cholesterol efflux, including ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette subfamily G member 1 (ABCG1), scavenger receptor class B type I (SR-BI), and peroxisome proliferator-activated receptor γ (PPAR-γ). In vivo, JP inhibited the expression of the Toll-like receptor 9 (TLR9)-induced signaling pathway, which links TLR9/MyD88/NF-kB to the expression of subsequent inflammatory factors. Furthermore, JP inhibited the expression of TLR9 and MyD88 in vitro. In addition, the JP treatment effectively reduced foam cell formation in RAW264.7 macrophages by increasing the expression of ABCA1/G1, PPAR-γ and SR-BI.

CONCLUSIONS

JP played a therapeutic role in ApoE^-/- mice with pristane-induced lupus-like diseases and AS, possibly through inhibition of TLR9/MyD88 signaling and promotion of cholesterol efflux.

Epitope of antiphospholipid antibodies retrieved from peptide microarray based on R39-R43 of β2-glycoprotein I

Background

Antiphospholipid antibody (aPL) syndrome (APS) is an autoimmune disease characterized by the presence of antiphospholipid antibodies and thromboembolic or pregnancy complications. Although cryptic epitope R39-R43 belonging to beta-2-glycoprotein 1 (β2GP1) has been identified as the main antigenic determinant for aPLs, we have recently demonstrated that the epitope is a motif determined by the polarity, rather than by the sequence or charge of amino acids.

Objective

In the present study, we wanted to identify the association of residues needed to obtain the highest aPL affinity.

Methods

Based on the epitope R39-R43 and our identified motif, we generated a printed peptide microarray of 676 different peptides. These peptides have been then screened for their ability to interact with the plasmas from 11 well-characterized APS patients and confirmed by surface plasma resonance assay.

Results and Conclusions

We identified a peptide that selectively bound immunoglobulin G (IgG) derived from APS patients with 100 times more affinity than β2GP1, Domain I, or epitope R39-R43. This peptide is able to inhibit the activity of IgG derived from APS patients in vitro. We have also generated a monoclonal IgG antibody against this peptide. Using both peptide and monoclonal antibody, we have been able to develop a fully standardized indirect colorimetric immunoassay with highly sensitivity. The identification of the optimized peptide offers a new standardized and accurate tool for diagnostics of APS. Furthermore, having increased affinity for aPL, this peptide could represent a useful tool as prevention strategy for APS and an alternative to the use of anticoagulants.

Surgical treatment of acute aortic dissection in a patient with SLE and prior antiphospholipid syndrome on therapy for over 30 years: a case report

BACKGROUND

In patients with systemic lupus erythematosus (SLE), lengthy treatment and long-term steroid use are the main risk factors for developing aortic aneurysms or aortic dissections. In patients with cardiac tamponade, hemodynamic collapse may lead to acute renal and hepatic failure.

CASE PRESENTATION

We report the successful treatment of a 55-year-old woman with SLE since the age of 21. She suddenly felt chest pain approximately 2 weeks before developing fever and vomiting and was admitted to our hospital. Initially, she had severe liver dysfunction and was admitted to the hepatology department, where treatment for fulminant hepatitis was initiated. However, computed tomography (CT) showed an acute aortic dissection (DeBakey type II) and severe bloody pericardial effusion. Therefore, we performed emergency pericardial drainage. Plasma exchange therapy was initiated as emergency aortic surgery was deemed impossible due to impaired liver function tests and coagulation. Ten days later, the patient developed peritonitis due to small bowel perforation, and laparotomy was performed for abscess drainage and perforation closure. She had received steroid pulse therapy at the age of 21. At 40 years of age, she developed deep vein thrombosis due to antiphospholipid antibodies and was prescribed prednisolone. She was ambulatory at 3 months after the onset of acute aortic dissection, and CT revealed a rapidly enlarging true aneurysm in the distal arch. We performed elective aortic surgery. Although there were no antiphospholipid antibodies, surgery could have led to a devastating antiphospholipid syndrome. Therefore, we decided to treat the patient with triple therapy. Methylprednisolone was intravenously administered intraoperatively and at 1 day postoperatively. The patient was discharged without complications after returning to her usual oral prednisolone regimen.

CONCLUSIONS

The patient described herein had a systemic circulatory failure due to cardiac tamponade, accompanied by liver failure. This condition is a significant cause of death in patients with aortic dissection-associated SLE and is extremely dangerous. However, multi-specialty intervention helped the patient recover, and she has been attending the outpatient clinic. Aortic surgery requiring hypothermia in SLE patients with antiphospholipid syndrome and a history of thrombocytopenia or thrombosis requires a multi-disciplinary treatment team, including cardiac surgeons and medical experts.

Vascular Inflammation in Mouse Models of Systemic Lupus Erythematosus

Vascular inflammation mediated by overly activated immune cells is a significant cause of morbidity and mortality in systemic lupus erythematosus (SLE). Several mouse models to study the pathogenesis of SLE are currently in use, many of which have different mechanisms of pathogenesis. The diversity of these models allows interrogation of different aspects of the disease pathogenesis. To better determine the mechanisms by which vascular inflammation occurs in SLE, and to assist future researchers in choosing the most appropriate mouse models to study cardiovascular complications in SLE, we suggest that direct comparisons of vascular inflammation should be conducted among different murine SLE models. We also propose the use of in vitro vascular assays to further investigate vascular inflammation processes prevalent among different murine SLE models.

Effects of swimming on the development of atherosclerosis in mice

OBJECTIVE

To investigate the effects of swimming on the formation of atherosclerotic lesions and the corresponding mechanism.

METHODS

20 ApoE-deficient young male mice of SFP grade were assigned equally into two groups: atherosclerosis group and swimming group. Atherosclerosis models were established by feeding with high cholesterol diet. Swimming exercise was performed at a frequency of 90 min per day, 6 days per weeks for 10 weeks. The weight index, histologic changes of aorta area, blood lipid levels, expression levels of eNOS, tNOS and iNOS, expression levels of MMP-9 and MMP-14, inflammatory factor levels, and oxidative stress status were compared between the two groups.

RESULTS

Compared to the atherosclerosis group, the plaque area, plaque rupture rates, and vulnerable index in the aorta of the swimming group were significantly less and the fibrous cap thickness was greater. The weight of mice and serum lipid levels in the swimming group were superior. In addition, in contrast to atherosclerosis group, mRNA expression levels of eNOS, tNOS, iNOS, and SOD in the swimming group were signifiantly elevated, while the levels of MMP-9, MMP-14 and MDA, and serum levels of IL-6, Lp-PLA2, and TNF-α were significantly decreased.

CONCLUSION

Swimming exercise significantly decreases the development of atherosclerotic plaque in ApoE-deficient mice, possibly due to a reduction in the expression of blood lipid, MMP-9, MMP-14, MDA, IL-6, Lp-PLA2, and TNF-α and elevation in the expression of eNOS, tNOS, iNOS, and SOD.

Assessment and management of the heightened risk for atherosclerotic cardiovascular events in patients with lupus erythematosus or dermatomyositis

For patients with lupus erythematosus (LE) or dermatomyositis (DM), there is an urgent need to address a heightened risk of clinical events, chiefly heart attacks and strokes, caused by atherosclerotic cardiovascular disease (ASCVD). Patients with LE or DM frequently exhibit high levels of conventional risk factors for ASCVD events, particularly dyslipoproteinemia and hypertension; an amplified burden of atherosclerotic plaques; and increased age- and sex-adjusted rates of ASCVD events compared with the general population. The rate of ASCVD events exceeds what would be expected from conventional risk factors, suggesting that disease-specific autoimmune processes exacerbate specific, known pathogenic steps in atherosclerosis. Importantly, despite their heightened risk, patients with LE or DM are often undertreated for known causative agents and exacerbators of ASCVD. Herein, we propose an approach to assess and manage the heightened risk of ASCVD events in patients with LE or DM. Our approach is modeled in large part on established approaches to patients with diabetes mellitus or stage 3 or 4 chronic kidney disease, which are well-studied conditions that also show heightened risk for ASCVD events and have been explicitly incorporated into standard clinical guidelines for ASCVD. Based on the available evidence, we conclude that patients with LE or DM require earlier and more aggressive screening and management of ASCVD. We suggest that physicians consider implementing multipliers of conventional risk calculators to trigger earlier initiation of lifestyle modifications and medical therapies in primary prevention of ASCVD events, employ vascular imaging to quantify the burden of subclinical plaques, and treat to lower lipid targets using statins and newer therapies, such as PCSK9 inhibitors, that decrease ASCVD events in nonautoimmune cohorts. More clinical vigilance is needed regarding surveillance, prevention, risk modification, and treatment of dyslipidemias, hypertension, and smoking in patients with LE or DM. All of these goals are achievable.