Faculté de Médecine, Université Paris Descartes, EA4466, Sorbonne Paris Cité, F-75006 Paris, France.
J Clin Endocrinol Metab. 2013 May;98(5):2084-9. doi: 10.1210/jc.2012-3794. Epub 2013 Mar 20.
Apelin and vasopressin levels are regulated in opposite directions to maintain body fluid homeostasis.
We thus assessed plasma apelin to copeptin ratios, with plasma copeptin concentrations as a reliable index of vasopressin secretion, in pathological states combining high levels of vasopressin secretion with hyponatremia.
DESIGN, PARTICIPANTS, AND SETTING: We carried out a cross-sectional study including 113 healthy subjects, 21 hyponatremic patients with the syndrome of inappropriate antidiuretic hormone (SIADH), and 16 normonatremic and 16 hyponatremic patients with chronic heart failure (CHF) in an academic hospital.
Individual apelin to copeptin ratios were plotted against natremia and compared with those of 10 healthy subjects of a previous study acutely challenged by water loading or hypertonic saline infusion. We calculated the percentage of SIADH/CHF patients whose apelin to copeptin ratio for a given natremia lies outside the 95% prediction limits of the physiological relationship.
In healthy subjects, median (interquartile range) plasma apelin and copeptin concentrations were 254 fmol/mL (225-311) and 4.0 fmol/mL (2.6-6.9), respectively. Sex- and age-adjusted plasma apelin concentrations were 26% higher in SIADH and normonatremic and hyponatremic CHF patients than in healthy subjects. Sex- and age-adjusted plasma copeptin concentration was 75%, 187%, and 207% higher in SIADH and normonatremic and hyponatremic CHF patients, respectively, than in healthy subjects. During an acute osmotic challenge, the plasma apelin to copeptin ratio decreased exponentially with natremia. Apelin to copeptin ratios as a function of natremia were outside the 95% predicted physiological limits for 86% of SIADH patients and 81% of hyponatremic CHF patients.
Inappropriate apelin concentrations and apelin to copeptin ratios as a function of natremia in SIADH and CHF patients suggest that the increase in plasma apelin secretion cannot compensate for the higher levels of vasopressin release and may contribute to the corresponding water metabolism defect.
阿片肽和血管加压素的水平呈相反方向调节，以维持体液平衡。
因此，我们评估了血浆阿片肽与 copeptin 的比值，以 copeptin 浓度作为血管加压素分泌的可靠指标，用于合并高血管加压素分泌和低钠血症的病理状态。
设计、参与者和设置：我们进行了一项横断面研究，包括 113 名健康受试者、21 名抗利尿激素不适当综合征（SIADH）伴低钠血症患者、16 名正常钠血症和 16 名低钠血症慢性心力衰竭（CHF）患者，在一家学术医院进行。
个体阿片肽与 copeptin 的比值与钠浓度进行绘制，并与先前研究中 10 名健康受试者在急性水负荷或高渗盐水输注时的比值进行比较。我们计算了给定钠浓度下，SIADH/CHF 患者的阿片肽与 copeptin 比值超出生理关系 95%预测范围的百分比。
在健康受试者中，中位（四分位间距）血浆阿片肽和 copeptin 浓度分别为 254fmol/ml（225-311）和 4.0fmol/ml（2.6-6.9）。与健康受试者相比，SIADH 和正常钠血症及低钠血症 CHF 患者的性别和年龄调整后血浆阿片肽浓度分别高 26%。与健康受试者相比，SIADH 和正常钠血症及低钠血症 CHF 患者的性别和年龄调整后血浆 copeptin 浓度分别高 75%、187%和 207%。在急性渗透挑战中，血浆阿片肽与 copeptin 的比值随钠浓度呈指数下降。钠浓度与阿片肽与 copeptin 比值的函数关系，对于 86%的 SIADH 患者和 81%的低钠血症 CHF 患者，超出了 95%预测的生理范围。
SIADH 和 CHF 患者中不适当的阿片肽浓度和钠浓度下的阿片肽与 copeptin 比值表明，血浆阿片肽分泌的增加不能补偿更高水平的血管加压素释放，可能导致相应的水代谢缺陷。
