The Association Of Serum MMP-3with Disease Activity And Joint Destrucion In Female Patients With Rheumatoid Arthritis

Backgroud and objectiveRheumatoid arthritis (RA) is a common chronic autoimmune diseasecharacterized by synovial proliferation, which causes progressive and irreversiblearticular cartilage and bone destruction, and ultimately lead to joint deformity anddisability. Two of the most important pathological features in RA are synovitis andjoint destruction. Synovitis mainly manifest as dysplasia of lining layer of synovialcells and infiltration of inflammatory cells. Fibroblast-like synoviocytes (FLS) are keyeffector cells mediating synovium inflammation and joint destruction. Jointdestruction is the most harmful pathological process in RA. Synovial pannus invadecartilage and secrete matrix metalloproteinases (MMPs) to decompose cartilagematrix, and thus causing damage of cartilage and bone.The occurrence and development of RA are promoted by abnormal expression ofMMPs, and MMP-3is the most important one. In the process of activating MMPsproenzymes, MMP-3proenzyme is activated as active MMP-3by fibrinolysin firstly,and then other MMPs proenzymes are actived by active MMP-3. MMP-3plays anextensive role in degrade matrix. MMP-3is mainly produced by synovial cells,fibroblasts and chondrocytes which are stimulated by IL-1and TNF-α. MMP-3isoverexpressed in RA synovial tissue; MMP-3levels are increase dramatically insynovial fluid, MMP-3levels in synovial fluid are significantly higher than in serum;serum MMP-3levels elevate with increased number of damaged joints. The above indicates that serum MMP-3is mainly derived from joints. The degradated productsof MMP-3can promote activation of T cell and induce the generation of multiplecytokines, resulting in aggravation of inflammation in joints. MMP-3is a criticalprotease for degrading cartilage; the role of MMP-3in RA joint destruction includestwo main parts: Firstly, MMP-3mRNA is overexpressed in the connection betweensynovial pannus and cartilage, MMP-3can directly degrade cartilage and bone.Synovial fluid MMP-3also directly degrades cartilage and bone where withoutsynovial membrane covering. Secondly, angiogenesis is a distinguishing feature ofRA aggressive synovial pannus. MMP-3digests microvascular basement membraneand stroma in the process of synovial angiogenesis.MMP-3plays an important role in RA synovial inflammation and jointdestruction. So, further exploration is warranted to analyze whether serum MMP-3inRA patients can be used as indicator of synovitis and joint destruction. It had beenreported that serum MMP-3levels in active RA patients was significantly higher thanin normal control. But there were few reports about close dynamic follow-up of serumMMP-3levels before and after treatment and the relationship between serum MMP-3levels and joint destruction in active RA patients.This study was designed to observechanges of serum MMP-3levels in RA patients before and after treatment, andanalyzes the correlation between serum MMP-3levels and disease activity indicatorsand or joint destruction indicators. The aim of this study is to evaluate whether serumMMP-3can reflect disease activity and predict the occurrence of joint destruction inRA patients, and to provide theory evidence for the clinical application of serumMMP-3.Materials and methodsWe recruited eighty-three female RA patients and thirty-one normal women ascontrol group. RA patients included fifty-eight active patients and twenty-fiveremissive patients，active RA patients were followed-up at the3th,6th,9th, and12thmonths after treatment. At different followed-up times, parameters of disease activityindicators were collected and DAS28(3)-CRP scores were counted by rheumatologist,hands X-ray Sharp scores were assessed by a radiologist. Serum MMP-3levels weremeasured by ELISA; serum bone formation markers such as N-MID.OS and PINPand bone resorption marker such as β-crosslap were measured by electrochemilumin- escence. We compared the difference of serum MMP-3levels among active RApatients, remissive RA patients and normal control, and observed the changes ofserum MMP-3levels before and after treatment, and analyzed the correlationsbetween serum MMP-3levels and disease activity indicators or joint damageindicators.Results1Baseline data in female RA patientsThere was no statistically difference of age among active RA patients, remissiveRA patients and normal control. Compared with remission RA patients, diseaseactivity indicators such as duration of morning stiffness, pain VAS scores of patient,pain VAS scores of doctor, TJC, SJC, functional status score of patient, HAQ, CRP,ESR, RF and DAS28(3)-CRP were increased obviously in active RA patients(P<0.05).2The relationship between serum MMP-3levels and disease activity in female RApatients at baseline2.1The comparison of serum MMP-3levels among female active RA patients,remission RA patients and normal control at baseline.Serum MMP-3levels of active RA patients, remission RA patients and normalcontrol were227.35(19.79~913.40) ng/ml,77.34(16.15~308.30) ng/ml and49.00(22.00~73.00) ng/ml respectively. There was statistically difference of serum MMP-3levels among active RA patients, remission RA patients and normal control (χ~2=61.88,P<0.001). Further pairwise comparisons showed serum MMP-3levels of active orremissive RA patients were higher than normal control (P<0.001). Serum MMP-3levels of active RA patients were higher than remissive RA patients, too (P<0.001).2.2The comparison of serum MMP-3levels among different grades of activity RApatients at baselineAccording to DAS28(3)-CRP, active RA patients were divided into low, mediumand high activity patients. Serum MMP-3levels of remission, low activity, mediumactivity and high activity RA patients were227.35(19.79~913.40) ng/ml,77.34(16.15~308.30) ng/ml and49.00(22.00~73.00) ng/ml respectively. Further pairwise compar- esons showed serum MMP-3levels of RA patients were higher in high, medium andlow activity groups than in remission group (P<0.05).2.3The correlation between serum MMP-3levels and disease activity indicators infemale RA patients at baseline.Serum MMP-3levels of all RA patients were positive correlated with pain VASscores of patients, pain VAS scores of doctors, functional status score of patients, SJC,TJC, HAQ, CRP, ESR and DAS28(3)-CRP (r=0.35,0.38,0.42,0.32,0.34,0.43,0.58,0.48,0.46; P<0.05).2.4The value of serum MMP-3levels for diagnosing female RA and disease activityat baseline2.4.1The sensitivity and specificity of serum MMP-3levels for diagnosing RApatientsAccording to serum MMP-3detective kit instruction, the female normal range is18~60ng/ml. At baseline, serum MMP-3levels of all RA patients, active RA patientsand remission RA patients greater than60ng/ml were true positive, less than60ng/mlwere false negative. Serum MMP-3levels of normal female greater than60ng/mlwere false positive, less than60ng/ml were true negative. The results suggested thatsensitivities of serum MMP-3for diagnosis of RA patients, active RA patients andremission RA patients were79.52%,91.38%and52.00%; the highest sensitivity wasfor diagnosing active RA.2.4.2The value of serum MMP-3levels for diagnosing female RA patientsCompared with normal control, the higher levels of serum MMP-3, the greaterpossibility for diagnosing RA; the AUC of RA, active RA and remission RA were allgreater than0.8; the value of diagnosis was best for active RA (AUC=0.97), theoptimal cutoff value of serum MMP-3level was57.81ng/ml when the highest Youdenindex is0.88; the optimal cutoff value of serum MMP-3level in all RA patients was57.81ng/ml when the highest Youden index was0.66.2.4.3The value of serum MMP-3levels for diagnosing disease activity in female RApatientsCompared with remission RA, the higher levels of serum MMP-3, the greater possibility of diagnosing the activity of RA; the AUC of active RA, low, medium andhigh activity RA groups were all greater than0.75, the value of diagnosis was best inlow active RA (AUC=0.81), the optimal cutoff value of serum MMP-3level was128.90ng/ml when the highest Youden index was0.51.3Changes of serum MMP-3levels in dynamic follow-up and its relationship withchanges of disease activity in female active RA patients3.1Changes of disease activity after treatment in female active RA patientsFourteen cases of female active RA patients were followed up at the3th,6th,9th,12th months after treatment. There were fourteen cases, eleven cases, eight cases andsix cases of RA patients at each follow-up month.Parameters of active RA patients at the3th,6th,9th, and12th months weresignificantly lower than at the baseline (P<0.05), these parameters includes pain VASscores of patient, pain VAS scores of doctor, SJC, HAQ, CRP, ESR and DAS28(3)-CRP; morning stiffness time and TJC at the3th,6th and9th months weresignificantly decreased than at the baseline (P<0.05). CRP at the12th month issignificantly lower than at the6th month (P<0.05).3.2Serum MMP-3levels in female active RA patients after treatmentSerum MMP-3levels of active RA patients at baseline, the3th, the6th, the9th,the12th months were131.00(19.79~759.40) ng/ml、97.40(23.96~560.40) ng/ml、34.38(16.15~658.30) ng/ml、35.16(22.92~77.34) ng/ml and44.92(25.78~77.34)ng/ml respectively. Serum MMP-3levels of active RA patients at the6th,9th,12thmonths were decreased significantly than at baseline (P<0.05), and the most obviousreduction of serum MMP-3levels was at the12th month. Serum MMP-3levels at the6th month were also decreased significantly than at the9th month (P<0.05).4The relationship between serum MMP-3levels and joint destruction in RA patients4.1The correlation between serum MMP-3levels in female RA patients and bonemetabolism markers at baselineAt baseline, fifty-eight out of eighty-three cases of recruited female RA patients(including forty-eight active RA patients and ten remissive RA patients) weremeasured peripheral serum bone metabolism markers. Correlation analysis showed that there was no significant correlation between serum MMP-3levels and boneformation markers such as PINP and N-MID.OS or bone resorption markers such asβ-crosslap in RApatients, active RApatients or remission RApatients (P>0.05).4.2Changes of serum MMP-3levels in dynamic follow-up and its relationship withchanges of bone metabolism markers in female active RA patientsSeven out of all the baseline female active RA patients were followed-up, bonemetabolism markers were measured at the3th month, the6th month. There was nostatistically difference of PINP (χ~2=3.43), N-MID.OS (χ~2=1.05),β-crosslap (χ~2=3.30),and MMP-3(χ~2=3.07)among the followed-up months (P>0.05). Further pairwisecomparison results showed changes of serum MMP-3levels within three or sixmonths were positive correlated with changes of β-crosslap within six months(r=0.83,0.83;P<0.05). There were no correlation between changes of serum MMP-3levels and changes of bone formation markers (P>0.05).4.3The correlation between serum MMP-3levels and hands X-ray Sharp scores infemale RA patients at baselineAt baseline, forty-eight out of eighty-three cases of recruited female RA patients(including thrity-eight active RA patients and ten remissive RA patients) wereassessed hands X-ray sharp scores. Correlation analysis showed that serum MMP-3levels was positive correlated with hands X-ray Sharp narrow scores, Sharp erosionscores and Sharp total scoresin RA patients (r=0.43,0.42; P<0.05). The serum MMP-3levels was also positive correlated with hands X-ray Sharp narrow scores and Sharptotal scores in active RA patients (r=0.37,0.33; P<0.05). There was no significantcorrelation between serum MMP-3levels and hands X-ray Sharp scores in remissionRA patients.4.4Changes of serum MMP-3levels in dynamic follow-up and its relationship withchanges of hands X-ray Sharp scores in female active RA patientsForteen out of all the baseline female active RA patients were followed-up andassessed hands X-ray sharp scores. Hands X-ray sharp scores were measured at the6th month, the12th month after treatment. There was no statistically difference ofSharp narrow scores (χ~2=3.43), Sharp erosion scores (χ~2=1.05), Sharp total scores(χ~2=3.30) and serum MMP-3level(χ~2=3.30) among the follow-up months (P≥0.05). Further pairwise comparisons showed change of serum MMP-3levels within threemonths was positive correlated with change of Sharp erosion scores within six months(r=0.60, P<0.05). The change of serum MMP-3levels within six months was positivecorrelated with changes of Sharp total scores within six and twelve months (r=0.75,0.81; P<0.05).Conclusions1Serum MMP-3levels were positive correlate with disease activity indicators infemale RA patients, the higher levels of serum MMP-3, the severer disease of activity;the serum MMP-3levels reduce with disease activity decrease or remission aftertreatment; MMP-3may be used to monitor disease activity change before and aftertreatment.2After treatment, the decreased levels of serum MMP-3in female RA patientswere positively correlated with decrease levels of β-crosslap, indicating that serumMMP-3may be used to evalute bone resorption.3The serum MMP-3level in female active RA patients may reflect the narrowand erosion of joints, indicating that serum MMP-3may be used as indicators tomonitor joint cartilage and bone destruction.