The Preventive Effects And Mechanism Of DMARDs On Early-onset Atherosclerosis In Patients With Rheumatoid Arthritis

Objective: Rheumatoid Arthritis(RA)is an autoimmune disease that the main pathologic change is chronic inflammations including synovitis and vasculitis across the whole body. It is one of the main reasons leading to the loss of labour force in our country. With the improvement of therapy strategy, the arthritis mutilans has been noticeably ameliorated,and the living conditions of the sufferers have been greatly improved. However, recent studies show that the risks of patients with RA getting cardiovascular and cerebrovascular diseases have been obviously increased. Nearly 50% death causes of RA patients are cardiovascular disease(CVD).The main cause of CVD is that chronic inflammation results in premature atherosclerosis upon patients with RA. Therefore, to explore the related mechanism of RA and adopt effective treatments have significant clinical meaningfulness for reducing the mortality of cardiovascular and cerebrovascular diseases and further improving the quality of lives of those patients.High-mobility group box protein 1(HMGB1) is the significant inflammatory factor during the onset of RA. It participates in the occurring and developing process of atherosclerosis by affecting the functions of monocytes and macrophages, vascular endothelial cells and Vascular smooth muscle cell (VSMC), which could promote local inflammatory reactions and assemble monocytes and macrophages, chemotaxis of VSMC and its cytoskeleton reconstruction. By inference, reducing the expression level of HMGB1 by reasonable interventions maybe reduce the morbidity of atherosclerosis of patients with RA and decrease the mortality .Vascular cell adhesion molecule-1(VCAM-1), also known as INCAM or CD106, belongs to the immunoglobulin superfamily. It causes endothelial damages and local assemblage of monocytes and macrophages as its expression increases. Moreover, under the circumstances of hyperlipidemia, macrophages become foam cells through scavenger -receptor identified and oxidized low-density lipoprotein. These have been the foundations of fibrous plaque and atherosclerosis. HMGB-1 has the function of stimulating the release of VCAM-1 by macrophages. By inference, it can be expected to lessen the expression of CD106, hold back the progress of atherosclerosis of patients with RA and reduce the mortality by suppressing the expression of HMGB1, which is the inflammatory medium, through reasonable interventions.The long-time application of disease-modifying antirheumatic drugs(DMARDs), including Methotrexate (MTX), Hydroxychloroquine Sulfate (HCQ), and etc, could significantly reduce the mortality of CVD of patients with RA. Different DMARDs has Different functioning mechanisms, MTX can restrain the inflammatory reactions directly, but HCQ reduces the risky factors of atherosclerosis to lower the morbidity of CVD by influencing on lipid metabolism, anti-platelet aggregation, and etc. However, there are few studies about whether DMARDs could reduce the risks of CVD of patients with RA through suppressing the expressions of HMGB1 and VCAM-1. Therefore, to probe into the effects of DMARDs interventions and possible mechanisms on early-onset atherosclerosis of patients with RA are helpful to reduce the mortality of cardiovascular .This study was carried out by means of clinical case-control study first of all. After interventions by DMARDs, reverse transcriptase-polymerse chain reaction (RT-PCR) was used to detect the expression of HMGB1 mRNA and flow cytometry (FCM) was used to measure the expression of CD106 on peripheral blood mononuclear cell (PBMC). At the same time, routine methods were carried out to detect the level of blood-lipid and carotid intima-media thickness(cIMT). To explore the effect of DMARDs on blood-lipid and the expressions of HMGB1 and CD106 maybe provide theoretical basis for the prevention of early-onset atherosclerosis of patients with RA.Methods:1 Collecting 69 outpatients and inpatients from our hospital who confirmed to the revised classified diagnosis criteria of American College of Rheumatology in 1987. All the patients with RA were divided into two groups: the treatment group (including 39 patients) and non-treatment group (including 30 patients). At the same time, collecting 27 healthy volunteers matching age and sex composed the healthy group. All those in the groups had no smoking experiences nor combined tumor or infectious diseases. In non-treatment group, patients did not receive normal therapy with active conditions. In treatment group, patients received DMARDs treatment more than one year with inactive conditions, including sulfasalazine suppository, hydroxychloroquine, penicillamine, methotrexate,leflunomide and etc.2 Recording the related information about those in the groups: name, gender, age, period of illness, duration of morning stiffing, treatment period with DMARDs, medication type and time, fatigue states of joints.3 Detecting the carotid intima-media thickness by means of ultrasonic diagnostic apparatus.4 Collecting 10ml of fresh vein blood from all patients between 8:00~10:00: detecting ESR with Westergren method, detecting RFand CRP with rate nephelometry, detecting the indexes of TC,TG,HDL and LDL with Japanese 7200 automatic biochemical analyzer. Detecting the expression of CD106 and HMGB1mRNA in PBMC by flow cytometry and RT-PCR respectively.5 Carrying on statistical analysis by SPSS13.0 statistical software, measurement information and data indicated by x±s. T-test for two-sample comparison of mean , one-way ANOVA for comparisons between multi-group. Pearson correlation analysis was adopted between parameters. There was statistical difference when P data is lower than 0.05. Results:1 The effect of DMARDs on blood- lipid of patients with RAThe TC,TG and LDL levels in non-treatment group were significantly higher than those in health control group (p<0.01),and the HDL level was significantly lower reversely (p<0.01). Compared with non-treatment group, TG and LDL levels in treatment group were significantly decreased(p<0.01), and the HDL level significantly increased(p<0.01).2 The effect of DMARDs on cIMT of patients with RAThe cIMT of patients with RA were higher than the healthy control group(p<0.05), but there were no statistical difference between treatment group and non treatment group.3 The effect of DMARDs on the expression of CD106 in PBMC of patients with RAThe levels of CD106 in PBMC of RA patients were obviously higher than the health control group(p<0.01). After treatment by DMARDs, the levels of CD106 were obviously lower than those in non- treatment group(p<0.01), but still apparently higher than those in health control group(p<0.01).4 The effect of DMARDs on the expressions of HMGB1 mRNA in PBMC of RA patients.The relative expression of HMGB1mRNA of patients with RA in treatment group(3.0±0.56)was obviously lower than those in non- treatment group(4.3±0.09)(P<0.01),but still higher than those in health control group(1.2±0.13)(P<0.01)。5 The correllation analysis between various clinical indicators and CD106 of RA patients.Pearson relative analysis reveals that: CD106 level was positively correlated with the cIMT of RA patients, and negatively correlated with the level of HDL, and was not correlated with the period of illness , ESR,CRP,RF,TG,TC and LDL levels.Conclusions:1 RA patients have abnormalities in lipid metabolism, and it is closely related with the extent of illness activities;2 The significant increment of CD106 and HMGB1expressions in PBMC of untreated RA patients, and the positive correlation between the expression of CD106 and carotid intima-media thickness suggest that this inflammatory medium have the effect of accelerating atherosclerosis.3 DMARDs can modify the abnormalities in lipid metabolism, reduce the expressions of HMGB1 and CD106 in PBMC of RA patients, and may defer the occurrence of atherosclerosis.In conclusion, improve lipid metabolism to reduce illness activities and then reduce the occurrence of early on-set atherosclerosis could be achieved by adjusting the levels of HMGB1and CD106 in PBMC of RA in early stage of DMARDs treatment. However, this study has not discovered the variations of carotid arteries IMT between treatment group and non-treatment group.This may be related with the reason of less samples and shorter illness period during which the intima structure abnormality didn't occur. Sample number could be increased in the next step to continue the study of correlation between illness and carotid arteries IMT...