Study Of The Relationship Between The Alterations Of Plasma Microparticles And Steroid-induced Osteonecrosis Of The Femoral Head

Background and ObjectivesSteroid-induced osteonecrosis of the femoral head(ONFH) is an aseptic and ischemic disease developing after steroid therapy by long-term use or high-dose given for short period.Especially,ONFH,the grave side-effect of steroid administration,occurred among many post-rehabilitation sufferers,after control of the global SARS prevalence in 2003.It is generally accepted that glucocorticosteroid is the first etio-factor for ONFH.However, the occurrence mechanism is unknown,and prevention methods and fundamental remedies remain to be established.It has been considered more and more intensively.Microparticles are circulating,phospholipid rich,submicron particles. Investigation into their biological activity has revealed diverse actions in coagulation,cell signalling and cellular interactions.Abnormal levels of microparticles have been found in a number of conditions associated with vascular dysfunction,thrombosis and inflammation.To further explore the pathogenesis,we study the relationship between the alterations of cell-derived microparticles(MPs) and steroid-induced ONFH.Materials and MethodsPlasma specimens from 24 patients with steroid-induced osteonecrosis of the femoral head(A group) and 24 age-,sex-and race-matched healthy controls(B group) were studied.Prothrombin time(PT),international normalized ratio(INR),fibrinogen(FG) and activated partial thromboplastin time(APTT) were analysed.Platelet-poor plasma was obtained by centrifugation.Plasma microparticles were labeled with monoclonal antibodies of PE-conjugated mouse anti-human CD31,CD54,and FITC-conjugated mouse anti-human CD42b,CD45,CD105,and PE-Cy5-conjugated mouse anti-human CD62E.Cell-derived microparticles were measured by three-colour flow cytometry.ResultsMean ranks of PT(21.42vs27.58,P=0.126),INR(22.23vs26.77, P=0.260),APTT(21.90vs27.10,P=0.197),all above in patients with steroid-induced osteonecrosis of the femoral head were lower than in healthy controls,while FG(27.35vs21.65,P=0.158) was going in opposite direction, and there were no statistical significance between two groups.All mean ranks of cell-drived microparticles in patients with steroid-induced osteonecrosis of the femoral head were lower than in healthy controls.Among them,there were statistical significance between two groups in CD31~+MPs (18.40vs30.60,P=0.002),CD31~+CD42b~+MPs(16.38vs32.63,P=0.000), CD31~+ CD45~+MPs(20.33vs28.67,P=0.020),while there was no statistical significance in CD42b~+MPs(21.83vs27.17,P=0.171),CD45~+MPs (21.77vs27.23,P=0.107 ),CD51/61~+MPs(21.65vs27.35,P=0.124), CD54~+MPs(22.79vs26.21,P=0.397 ),CD62E~+MPs(22.88vs26.13,P=0.421 ), CD105~+MPs(22.79vs26.21,P=0.338),CD54~+CD62E~+MPs(24.27vs24.73, P=0.910),CD31~+CD105~+MPs(23.42vs25.58,P=0.450).Conclusions1.Although there were no statistical significance between two groups in mean ranks of PT,INR,APTT and FG,all four clotting indexes uniformly suggested hypercoagulabale states in patients with steroid-induced osteonecrosis of the femoral head.2.All mean ranks of cell-drived microparticles in patients with steroid-induced osteonecrosis of femoral head were lower than in healthy controls,and there were statistical significance among some of them between two groups.It suggests that glucocorticosteroids might inhibit or interfere the formation and release of microparticles. 3.It might be responsible for steroid-induced osteonecrosis of femoral head that the disequilibrium of microparticle metabolism could result in microcirculation disturbance.