Determination of Prostacyclin in Plasma through a Bioluminescent Immunoassay for 6-Keto-prostaglandin F1 α:  Implication of Dosage in Patients with Primary Pulmonary Hypertension

• Published in: Analytical chemistry (Washington) 2002-08, Vol.74 (15), p.3892-3898
• Main Authors: Desai, Urvee A, Deo, Sapna K, Hyland, Kenneth V, Poon, Michael, Daunert, Sylvia
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Other biological molecules; Terpenes, steroids. Hormones
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac025518v

This work describes a solid-phase immunoassay for 6-keto-prostaglandin F1 α, the stable hydrolysis product of prostacyclin (prostaglandin I2). Prostacyclin, a potent vasodilator with antiplatelet and antiproliferative properties is an effective treatment for primary pulmonary hypertension and pulmonary arterial hypertension associated with scleroderma and scleroderma-like syndrome. Levels of 6-keto-prostaglandin F1 α can be directly correlated with levels of prostacyclin. Therefore, 6-keto-prostaglandin F1 α has become the indicator of choice to measure prostacyclin levels. The single-step immunoassay for 6-keto-prostaglandin F1 α reported here was developed using the bioluminescent protein aequorin as a label. Analyte−label conjugates were constructed by linking the carboxyl group of 6-keto-prostaglandin F1 α and lysine residues of aequorin by chemical conjugation methods. The binding properties of 6-keto-prostaglandin F1 α toward its antibody and the bioluminescent properties of aequorin were retained in the conjugate, which was then used to generate a dose−response curve for the analyte in a convenient microtiter plate format. The concentration of 6-keto-prostaglandin F1 α after extraction from plasma showed good correlation with the concentration of 6-keto-prostaglandin F1 α obtained without prior extraction of the same plasma sample. This measurement demonstrated that the assay allows the measurement of 6-keto-prostaglandin F1 α directly in plasma without any pretreatment of the samples, which results in a much simpler method with a faster assay time.