Study On Early - Onset Atherosclerosis Cohort Of Systemic Lupus Erythematosus And Its Mechanism

Backgrounds:Systemic lupus erythematosus (SLE) is one of systemic autoimmune diseases which can affect any human organ. The prevalence of SLE in China was estimated to be 70 cases per 100,000 persons; in addition it was more than 113/100,000 in women. Based on an estimated population of 1.37 billion published in 2013 in China, the number of Chinese SLE patients could be 1000,000, which would be the largest group of cases aroud the world. An increased prevalence of accelerated atherosclerosis in SLE patients has been established for many years. To better understand SLE and accelerated atherosclerosis in SLE patients, lupus registries and cohort studies have been created and maintained in the U.S. and Europe. Aim to clarify the natural history, and pathogenesis and provide valuable data to guide the appropriate clinical practice and improve the prognosis for SLE patients. however, there are limited epidemiological data on SLE in China. The Chinese SLE Treatment and Research group (CSTAR) developed the first online registry of Chinese lupus, which will provide a significant platform for learning accelerated atherosclerosis in SLE patients in Chinese patients. Besides, HDL’s cardioprotective effects are impaired and transfer to the pro-inflammatory HDL (piHDL) in SLE which contribute to changes in HDL related proteins.Methods:Polycentric prospective cohort study:Based on the CSTAR online registry, all patients with SLE were registered after informed consent forms were signed. All patients were interviewed and examined using a standardized data-collection instrument. Traditional cardiovascular risk factors, SLE-related parameters and cardiovascular events were assessed on the day that blood samples were harvested, laboratory tests, carotid intima-media thickness (CIMT) and carotid plaques were examined.Based on the same protocol-directed methods, all centers performed evaluations and record data for SLE patients. All patients with SLE were followed up for about 1 year and carried on a follow-up by phone or at outpatient department once every 3 months as well. The main data were composed of traditional cardiovascular risk factors, SLE-related parameters and cardiovascular events, carotid intima-media thickness (CIMT) and carotid plaques.SAS 9.3 was used to perform all statistical analyses, especially: ① The prevalence, awareness, treatment and control of traditional risk factors.② The prevalence clinical cardiovascular diseases. ③ The distribution of CIMT and carotid plaques and related risk factors. ④ The new clinical cardiovascular diseases and related risk factors.⑤New carotid plaques and changes of carotid intima-media thickness and related risk factors.Single-center case-control study and cohort study:Arterial stiffness was evaluated by measuring baPWV in SLE patients from the single center, Health Medicine in Peking Union Medical College Hospital (PUMCH). Traditional cardiovascular risk factors and SLE-related parameters were assessed on the day that brachial-ankle pulse wave velocity (baPWV) was examined. ① The distribution of arterial stiffness was compared with a control group of individuals which were matched for age and sex, randomly drawn by advertisement from volunteers in the Department of PUMCH. SAS 9.3 was used to perform all statistical analyses in this study. Linear regression and curvilinear regression models were utilized to investigate age-related progression of arterial stiffness among systemic lupus erythematosus (SLE) patients relative to healthy controls.② We conducted this study in the longitudinal SLE cohort from the CSTAR, including subjects with systemic lupus erythematosus disease activity index (SLEDAI)≥6 at baseline, We assessed the correlations between reductions in biomarkers of inflammation, SLEDAI and SLE therapeutics with changes in mean baPWV and lipoprotein profile respectively at baseline and 1-year follow-up.Basic study:Participants were from the above net-cohort study, experienced a reduction of mean baPWV> 5% from baseline to 1 year follow-up. Isobaric tags for relative and absolute quantitation (iTRAQ) combined with nano-flow liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) was performed to obtain a global and a differential expression profile of protein compositions of the HDL pooled samples. MetaCore was used to perform analyses of the molecular function, biological process and cellular component based on the Gene ontology. Western blotting was used to validate the relative increases in serum protein levels for two of the identified proteins.Results:Polycentric prospective cohort study:The baseline data consisted of 831 SLE patients, with a 30 years old median age.387 patients (83.0%) reached 1 year follow-up time and completed the follow-up, of which 240 people were re-measured carotid ultrasound after one year follow-up,3 deaths were exhibited (0.36%, including 2 infection cases and one pulmonary arterial hypertension case).① The prevalence、awareness, treatment and control rate of high blood pressure were 24.8%,49.0%,90% and 68.1%;high cholesterol were 65.9%,5.5%,50%及26.7%; high blood sugar were 9.0%,38.6%,55.2% and 87.5% and fat were 20.5%,5.3%,33% 及100%, respectively.② The cases of cardiovascular diseases were 41(4.9%), including 19 patients with coronary heart disease,18 patients with strokes and 4 patients with peripheral vascular disease. Multivariate logistic regression analysis revealed that age and diabetes were independent risk factors of severity of cardiovascular diseases.③ The left average IMT (common carotid artery) was 0.59 mm (SD,0.17) and the left was 0.58 mm (SD,0.17)。The proportion of intimal thickening percentage and carotid plaque were 23 (2.8%) and 41 (4.93%) respectively. Stepwise linear regression analysis showed that HDL-C and menopause were independent risk factors for the increasing carotid IMT.④ Cardiovascular events occurred in 2 patients, carotid artery plaque occurred in 1 patient and 2 had simple intima-media proliferation after one-year follow-up. The CIMT has averaged around 6.5% increase per year (SD,9.9%). Multiple linear regressions revealed that age, hypertension, SLE disease activity, ESR and cyclophosphamide usage were predictors of SLE patients with carotid artery intima growth.Case-control study:A total of 161 female SLE patients enrolled in the Chinese SLE Treatment and Research group (CSTAR) registry and 135 age-matched control subjects participated in this cross-sectional investigation. Arterial stiffness significantly differed between the SLE patients and controls in the different age groups, as well as within the SLE group. Curvilinear regression and linear regression revealed various trends of increased arterial stiffness among the SLE patients compared with the healthy controls. The correlation coefficients between age and arterial stiffness significantly differed among the SLE patients relative to the healthy controls. Multivariate analysis revealed that age, mean BP, ESR, prednisone course and SLE disease activity were associated with arterial stiffness among the SLE patients. Further, these patients exhibited earlier exposure to and higher frequencies of several risk factors compared with the controls in each age group.Single-center cohort study:We studied 59 SLE subjects (median age of 31 years, all female).We observed the reduction in SLEDAI was 6 (4-10) and the improvement in mean baPWV by 5.4% between baseline and follow-up. There was a significant improvement of lipid profile, including increased HDL-C of 15.5%, decreased TG of 74.3% and TC/HDL-C of 17.6%.We observed significant correlations between a reduction in ESR with decreases in TC/HDL-C, TG and mean baPWV. Furthermore, we observed a significant correlation between a reduction in SLEDAI with decrease in mean baPWV. After being adjusted for potential confounding factors the reduction in ESR remained significantly associated with the decreases in TC/HDL-C, TG and mean-baPWV. The reduction in SLEDAI remained significantly associated with mean-baPWV adjusted for age and blood pressure.Basic study:We studied 10 SLE subjects (median age of 28 years, all female).We observed the reduction in SLEDAI was 9 (3.0) and the improvement in mean baPWV by 15% between baseline and follow-up. There was no significant improvement of HDL-C levels (P=0.5825). We identified 24 of proteins related to HDL were significantly down regulated and 23 were significantly up-regulated with the reduction of disease activity and mean baPWV between the baseline and the follow-up. Many changeable proteins were related to acute inflammation, including apolipoprotein A-4 (apoA-4), apolipoprotein V-3 (apoC-3), lipopolysaccharide binding protein (LBP), serum amyloid A-1 (SAA1) and fibrinopeptide A (FIBA). Based on extracted ion chromatograms, we calculated that SAA1 decreased approximately 62% with 74% reduction of ESR and 15% reduction of mean baPWV between the baselines with the follow-up. In addition, we observed increases in the abundance of glutathione peroxidase 3 (GPX3), reflecting altered oxidation state of HDL. Western blotting was used to validate the relative increases in serum protein levels for SAA1 and FIBA.Conclusion:① In the CSTAR platform, this study described the prevalence, awareness, treatment and control rates of SLE patients with traditional risk factors, and clinical cardiovascular disease and subclinical atherosclerosis. Lastly, it provided the epidemiological data in the Chinese SLE patients.② The follow-up study described the incidence of new clinical cardiovascular diseases and subclinical atherosclerosis, and built CMT growth forecast model for the SLE patients in China.③ The mechanisms of the age-related progression of arterial stiffness differed among the SLE patients relative to the healthy controls. Furthermore, accelerated arterial stiffness was observed among the SLE patients relative to the controls with advancing age. Among premenopausal women, SLE disease activity plays a critical role in inducing the increase of vascular stiffness. Among postmenopausal women, both steroid accumulation and some traditional risk factors accelerated increasing of vascular stiffness.④ Among SLE subjects experiencing reductions in SLE disease activity, we observed improvements of lipoprotein profile and arterial stiffness. These findings provide further insight into the beneficial effect of reduction in inflammation on CVD risk in vivo.⑤ Among SLE subjects experiencing reductions in SLE disease activity and arterial stiffness, we observed improvements of HDL protein compositions. These findings provide further insight into the beneficial effect of reduction in inflammation on HDL’s cardioprotective functions.