维生素D系统和雌激素受体表达与初发系统性红斑狼疮患者骨量异常的关系

目的 了解初发系统性红斑狼疮(SLE)患者骨密度情况,通过检测患者体内维生素D(VitD)内分泌系统水平及雌激素受体(ER)水平,探讨其与骨密度之间的关系.方法 选上海交通大学医学院附属仁济医院风湿科就诊的初发SLE患者42例(初发SLE组)及在其院的健康体检者42例(健康对照组);ELISA检测2组受试者血浆中25-OH VitD_3、1,25-(OH)_2 VitD_3水平;实时定量PCR检测外周血淋巴细胞VitD受体(VDR)、ER-α、ER-β mRNA表达.双能X线检测2组受试者腰椎1～4和股骨近端骨密度.结果 (1)初发SLE组患者骨量减少的发病率(30.95%)高于健康对照组(4.76%,P<0.01).(2)初发SLE组患者25-OH VitD_3[(54.34±27.15)pmol/L]、1,25-(OH)_2VitD_3[(47.42±25.67)pmol/L]水平低于健康对照组[(89.99±16.85)pmol/L,(77.57±23.80)pmol/L,P<0.01],但在初发SLE组中骨量减少者[(45.90±28.11)pmol/L,(42.36±27.35)pmol/L]与骨量正常者[(58.12±26.32)pmol/L,(49.69±25.04)pmol/L]间差异无统计学意义(P>0.05);且25-OH VitD_3、1,25-(OH)_2 VitD_3水平与骨量不存在相关性(r=0.285,P=0.07;r=0.219,P=0.164).(3)初发SLE组患者VDR mRNA表达(△Ct为8.79±1.68)高于健康对照组(△Ct为11.42±1.96,P<0.01),但在骨量减少者(△Ct为9.43±1.53)与骨量正常者(△Ct为8.81±1.49)间差异无统计学意义(P>0.05),VDR mRNA表达与骨密度不存在相关性(r=0.130,P=0.413).(4)初发SLE组患者ER-β mRNA表达水平(△Ct为15.54±1.80)高于健康对照组(△Ct为16.61±1.29,P<0.01),但在骨量减少者(△Ct为15.98±2.40)与骨量正常者(△Ct为15.35±1.46)间差异无统计学意义(P>0.05).结论 SLE患者较健康人更易出现骨量减少.SLE患者体内存在VitD系统异常及ER-β基因表达增高,但其与骨量减少之间无明显相关性.

The relationship of vitamin D endocrine system and estrogen receptor expression with bone mineral density in initial systemic lupus erythematosus

Objective To study the incidence of osteopenia in patients with initial systemic lupus erythematosus(SLE). Investigate the levels of the vitamin D (VitD) endocrine system in peripheral blood of SLE patients and its relation to bone mineral density (BMD). Analyse the relationship between the estrogen receptor (ER) and BMD and evaluate the role of ER in the pathogenesis osteopenia. Methods Serum levels of 25-OH VitD_3 and 1,25-(OH)_2 VitD_3 were detected by enzyme linked immunosorbent assay. The gene expression levels of VitD receptor (VDR) and ER were determined by real-time PCR. BMD measurements in the lumbar spine (L1-L4) and left proximal femur (femoral neck) were performed using dual X-ray absorptiometry before treatment. Results The initial SLE patients had significantly lower BMD values, and higher frequency of bone loss at both sites of measurement compared with normal controls (P < 0. 05). The levels of 25-OH VitD_3 and 1,25-(OH)_2 VitD3 were lower in the initial SLE patients than normal controls(P<0.01 both). There is no difference in the levels of 25-OH VitD_3 and 1,25-(OH)_2 VitD_3 between the osteopenia SLE group and the normal BMD SLE group (P > 0. 05, P > 0. 05). There are no correlations between the Vitd and BMD in initial SLE patients (P>0.05 both). The expressions of VDR gene were significantly increased in the initial SLE patients compared with the normal controls(P<0.01). There was no difference in VDR gene expression between osteopenia SLE group and normal BMD SLE group (P>0.05). The VDR gene expression does not correlate with the bone mass (P>0.05). The levels of ER-β gene expression are higher in the initial SLE group than the normal controls (P<0.01).Conclusions The incipient SLE patients may have lower BMD than expected. SLE patients present abnormal VitD endocrine system and higher ER-β mRNA expression than those in normal controls, but these weren't concerned with osteopenia.