成纤维细胞生长因子23在继发性甲状旁腺功能亢进症中的作用

Role of fibroblast growth factor 23 in secondary hyperparathyroidism

目的研究成纤维细胞生长因子23（FGF23）在继发性甲状旁腺功能亢进症（SHPT）中的作用？方法（1）收集38例维持性血液透析（MHD）患者血清，用ELISA法检测FGF23和化学发光酶免疫分析法检测全段甲状旁腺激素（iPTH）。（2）6例行甲状旁腺全切除（PTX）加自体前臂移植术的SHPT患者，取其甲状旁腺组织行细胞培养。培养24h后用0.1mg／L的FGF23分别刺激0、6、12、24、48h时收集上清液检测iPTH。（3）取33例严重SHPT患者和3例健康人的甲状旁腺组织，用免疫组化SP法检测成纤维细胞生长因子受体（FGFR）1、FGFR3、转录因子GATA-3、增殖细胞核抗原（PCNA）及PV法检测Klotho的表达，计算阳性细胞率或积分吸光度。结果（1）MHD患者血清FGF23[（3901.85±2618.11）ng／L]与iPTH[（460.00±489.77）ng／L]呈正相关（r^2=0.3009，P=0.0004）。（2）FGF23仅在刺激24h时，才有抑制iPTH的作用（P〈0.05），其它时段均无抑制作用。（3）SHPT患者甲状旁腺PCNA、GATA-3、FGFR3、Klotho表达均显著高于健康人，而FGFR1表达显著低于健康人。（4）GATA-3阳性细胞率与血清iPTH水平及PCNA阳性细胞率均呈正相关（r^2=0.1901，P=0.0425；r^2=0.2584，P=0.0025）。Klotho表达与FGFR1和FGFR3表达呈正相关（r^2=0.2046，P=0.0082；r^2=0.2833，P=0.0014）。PCNA表达与FGFR1表达呈负相关（r^2=0.1292，P=0.0399）；与FGFR3表达呈正相关（r^2=0.1226，P=0.0457）。FGFR1表达和血清磷水平呈负相关（r^2=0.2329，P=0.0044）；与血清钙水平呈正相关（r^2=0.1422，P=0.0305）。结论MHD患者iPTH水平与FGF23水平呈正相关。FGF23能抑制iPTH分泌，但作用弱且短。这可能与GATA-3、甲状旁腺细胞增殖、FGFR3表达增多，FGRF1表达下降有关。

Objective To investigate the role of fibroblast growth factor-23 （FGF23） in secondary hyperparathyroidism（SHPT）. Methods （1） Serum FGF23 and intact parathyroid hormone （iPTH） from 38 maintenance hemodialysis （MHD） patients were measured by ELISA and chemiluminescence enzyme immunoassay respectively. （2） Parathyroid cells from six SHPT patients underwent parathyroidectomy with forearm autotransplantation were cultured for 24 h, then were induced by 0.1 mg/L FGF23. The supernatant was collected at 0, 6, 12, 24 and 48 h respectively. The concentration of iPTH was measured by chemiluminescence enzyme immunoassay. （3） Protein expression of Klotho, FGFR1, FGFR3, GATA-3 and PCNA in parathyroid tissue from 33 SHPT cases and 3 healthy people were detected by immunohistochenfistry SP and PV methods respectively. Positive cell rate and absorbance were calculated. Results （1） Serum FGF23 [（3901.85±2618.11） ng/L] was positively correlated with serum iPTH [（460.00±489.77） ng/L] in MHD patients. （2） 0.1 mg/L FGF23 suppressed iPTH secretion of parathyroid cells only at 24 h time point in vitro （P〈0.05）. （3） Expression of GATA-3, FGFR3, Klotho and PCNA was significantly increased and FGFR1 was significantly decreased in parathyroid tissue of SHPT patients as compared to healthy people. （4） Positive cell rate of GATA-3 was positively correlated with iPTH （r^2=0.1901, P=0.0425） and PCNA （r^2=0.2584, P=0.0025）. Klotho was positively correlated with FGFR1 and FGFR3 （r^2=0.2046, P=0.0082;r^2=0.2833, P=0.0014）. PCNA was negatively correlated with FGFR1 （r^2=0.1292, P=0.0399） and positively correlated with FGFR3 （P=0.1226, P=0.0457）. FGFR1 was negatively correlated with serum phosphate （r^2=0.2329, P=0.0044） and positively correlated with serum calcium （r^2=0.1422, P=0.0305）. Conclusions FGF23 level is positively correlated with iPTH level in MHD patients. FGF23 can inhibit iPTH secretion of parathyroid cells in a weak and short way, which may be associated with the proliferation of GATA-3 positive cells and parathyroid cells, the up-regulation of FGFR3 and the down-regulation of FGFR1 expression.