Sánchez Fructuoso A I, Maestro M L, Calvo N, De La Orden V, Pérez Flores I, Vidaurreta M, Valero R, Fernández-Pérez C, Barrientos A
Nephrology Department, Hospital Clinico San Carlos, Madrid, Spain.
Transplant Proc. 2012 Nov;44(9):2551-4. doi: 10.1016/j.transproceed.2012.09.070.
Persistence of inappropriately high serum levels of fibroblast growth factor-23 (FGF23), a recently discovered phosphaturic hormone, has been reported to play an important role in the pathogenesis of posttransplant hypophosphatemia. The aim of the present study was to evaluate FGF23 in the early posttransplant period and study the complex associations between FGF23, parathyroid hormone (PTH), 1,25(OH)(2) vitamin D, and phosphate in transplant patients.
We performed a cross-sectional observational study of 42 adult kidney recipients in the early posttransplant period (<6 months). Fasting serum samples and 24-hour urine samples were collected during a routine follow-up outpatient visit. Serum creatinine, calcium, phosphate, magnesium and urinary creatinine, calcium, magnesium, and phosphate were measured using standard assays. We also studied concentrations of 25 hydroxyvitamin D, 1,25(OH)(2) vitamin D, intact PTH, and circulating FGF23.
Median values for the different parameters studied were as follows: 9.9 ± 0.6 mg/dL, phosphatemia 3.3 ± 0.7 mg/dL, estimated glomerular filtration rate (eGFR; 41.1 ± 14.0 mL/min, phosphate reabsorption rate 68.4% ± 10.7%, PTH 94.5 ng/L (53.8-199.5), calcitriol 33.0 pg/mL (24.0-44.1), calcidiol 27.3 ng/mL (17.0-38.0), FGF23 139 pg/mL (88-221), and calciuria 62.5 mg/d (40.3-101.3). The variables significantly associated with serum FGF23 levels were phosphate reabsorption rate (r = .493; P = .001), calcitriol (r = .399; P = .009), eGFR (r = .557; P < .001), PTH (0.349; P = .024).
Elevated serum levels of FGF23 could explain the deficiency of calcitriol and elevated renal phosphorus wasting in the early posttransplant period. All treatments that can lead to increased serum phosphate levels (eg, oral medication or calcitriol) should be carefully evaluated, since increased phosphatemia could further stimulate secretion of FGF23 and prolong high phosphorus loss.
据报道，最近发现的一种排磷激素——成纤维细胞生长因子23（FGF23）血清水平持续异常升高，在移植后低磷血症的发病机制中起重要作用。本研究的目的是评估移植后早期的FGF23，并研究移植患者中FGF23、甲状旁腺激素（PTH）、1,25(OH)₂维生素D和磷酸盐之间的复杂关联。
我们对42例移植后早期（<6个月）的成年肾移植受者进行了一项横断面观察研究。在常规随访门诊就诊期间采集空腹血清样本和24小时尿液样本。使用标准检测方法测量血清肌酐、钙、磷酸盐、镁以及尿肌酐、钙、镁和磷酸盐。我们还研究了25羟维生素D、1,25(OH)₂维生素D、完整PTH和循环FGF23的浓度。
所研究的不同参数的中位数如下：血磷9.9±0.6mg/dL，血钙3.3±0.7mg/dL，估计肾小球滤过率（eGFR；41.1±14.0mL/min），磷酸盐重吸收率68.4%±10.7%，PTH 94.5ng/L（53.8 - 199.5），骨化三醇33.0pg/mL（24.0 - 44.1），骨化二醇27.3ng/mL（17.0 - 38.0），FGF23 139pg/mL（88 - 221），尿钙62.5mg/d（40.3 - 101.3）。与血清FGF23水平显著相关的变量有磷酸盐重吸收率（r = 0.493；P = 0.001）、骨化三醇（r = 0.399；P = 0.009）、eGFR（r = 0.557；P < 0.001）、PTH（0.349；P = 0.024）。
血清FGF23水平升高可以解释移植后早期骨化三醇缺乏和肾脏磷排泄增加的现象。所有可能导致血清磷酸盐水平升高的治疗方法（如口服药物或骨化三醇）都应仔细评估，因为血磷升高可能会进一步刺激FGF23的分泌并延长高磷丢失的时间。
