Brown S A, Ontjes D A, Lester G E, Lark R K, Hensler M B, Blackwood A D, Caminiti M J, Backlund D C, Aris R M
Division of Endocrinology, Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
Osteoporos Int. 2003 Jun;14(5):442-9. doi: 10.1007/s00198-002-1331-x. Epub 2003 May 28.
Osteoporosis is a well-defined health risk in cystic fibrosis (CF) patients due to many factors. Vitamin D insufficiency, despite routine cholecalciferol supplementation in CF patients, may contribute to a relative secondary hyperparathyroidism and possibly deficient bone mineralization. An alternate form of vitamin D, calcitriol, was studied to determine short-term effects on fractional calcium absorption and other calciotropic markers in 10 adult CF subjects and in 10 age-, sex- and body mass index (BMI)-matched controls. Serum fractional absorption of (45)Ca was determined after a calcium-containing meal prior to calcitriol intervention. Other measurements included serum parathyroid hormone (PTH), ionized calcium, 25-hydroxyvitamin D (25OHD), 1,25-dihydroxyvitamin D (1,25(OH)(2)D) and urinary calcium:creatinine and N-telopeptide (NTx) concentrations. Both groups were then given calcitriol (0.5 micro g p.o. b.i.d. for 14 days) and restudied following the same protocol. Both groups increased their fractional absorption of (45)Ca after calcitriol ( p=0.015 CF subjects, p=0.001 controls), although calcitriol tended to be less effective in the CF group compared with the controls ( p=0.055). Post-prandial serum PTH concentrations were suppressed compared with baseline in both groups ( p=0.03 CF subjects, p=0.006 controls). Urinary NTx concentrations, a marker for bone resorption, decreased significantly in CF subjects after calcitriol (96.0+/-16.0 vs 63.9+/-12.7 nmol BCE/mmol Cr, p=0.01) and remained unchanged in the control group. The controls had an increase in serum 1,25(OH)(2)D concentrations (69.9+/-4.2 vs 90.7+/-9.6 pmol/l, p=0.02) while there was no significant change in the CF group. Oral calcitriol administration appears to improve markers of calcium balance in adults with CF by increasing fractional absorption of (45)Ca and lowering PTH concentrations, similar to its known effects in healthy subjects, while also suppressing urinary NTx, a marker of bone turnover.
由于多种因素，骨质疏松症在囊性纤维化（CF）患者中是一种明确的健康风险。尽管CF患者常规补充胆钙化醇，但维生素D不足可能导致相对继发性甲状旁腺功能亢进，并可能导致骨矿化不足。研究了维生素D的另一种形式骨化三醇，以确定其对10名成年CF受试者以及10名年龄、性别和体重指数（BMI）匹配的对照者的钙分数吸收和其他钙调节标志物的短期影响。在骨化三醇干预前，进食含钙餐后测定血清（45）Ca的分数吸收。其他测量指标包括血清甲状旁腺激素（PTH）、离子钙、25-羟基维生素D（25OHD）、1,25-二羟基维生素D（1,25(OH)₂D）以及尿钙：肌酐和N-端肽（NTx）浓度。然后两组均给予骨化三醇（口服0.5μg，每日两次，共14天），并按照相同方案再次进行研究。骨化三醇治疗后，两组的（45）Ca分数吸收均增加（CF受试者p = 0.015，对照组p = 0.001），尽管与对照组相比，骨化三醇在CF组中的效果往往较差（p = 0.055）。与基线相比，两组餐后血清PTH浓度均降低（CF受试者p = 0.03，对照组p = 0.006）。尿NTx浓度是骨吸收的标志物，骨化三醇治疗后CF受试者的尿NTx浓度显著降低（96.0±16.0 vs 63.9±12.7 nmol BCE/mmol Cr，p = 0.01），而对照组保持不变。对照组血清1,25(OH)₂D浓度升高（69.9±4.2 vs 90.7±9.6 pmol/l，p = 0.02），而CF组无显著变化。口服骨化三醇似乎通过增加（45）Ca的分数吸收和降低PTH浓度来改善CF成年患者的钙平衡标志物，这与其在健康受试者中的已知作用相似，同时还能抑制尿NTx，即骨转换的标志物。
