Chromogranin A - unspecific neuroendocrine marker. Clinical utility and potential diagnostic pitfalls.
BACKGROUND The neuroendocrine marker, chromogranin A (CgA) increases during medium- or long-term proton-pump inhibitor (PPI) treatment. AIMS To analyze the effect of ultra-short-term and diverse dose of PPI therapy on serum CgA and gastrin levels and evaluate the effect of PPI treatment cessation. PATIENTS AND METHODS Fasting serum CgA and gastrin were determined in newly diagnosed gastroesophageal reflux disease (GERD) patients (n = 54) treated with diverse doses of PPI during a 28-day period, in patients treated with PPIs for at least 6 months (n = 42), and in subjects where PPI treatment could be stopped (n = 11). RESULTS A significant stepwise increase of CgA levels was observed after 5 days during the 28-day period treatment with all PPI doses. Gastrin increased significantly also in the standard and high-dose PPI subgroups. The most prominent increase of CgA was observed in the high-dose PPI subgroup. Serum CgA and gastrin were markedly elevated after 6 months of PPI treatment, and decreased significantly after 5 days of PPI discontinuation. CONCLUSIONS Serum CgA increases significantly even after ultra-short-term (5 days) PPI therapy. After long-term treatment, 5-day cessation of PPI therapy is sufficient to decrease significantly both CgA and gastrin levels.