GlycA: Evaluation of a New Biomarker of Acute Pancreatitis

Background: Acute pancreatitis (AP) is a leading cause of gastrointestinal hospital admissions, with up to 40% mortality in patients with moderate-severe AP. Glycoprotein acetylation (GlycA) is measured as a nuclear magnetic resonance signal (NMR) of the post-translational modification of glycosylated acute-phase proteins released during inflammation. We aimed to investigate the role of GlycA as an inflammatory biomarker of AP. Methods: We prospectively enrolled 20 AP patients and 22 healthy controls and collected EDTA plasma samples at admission and discharge. NMR spectra were acquired from these samples using a 400 MHz Vantera (R) Clinical Analyzer, and GlycA concentrations were calculated (normal = 400 mu mol/L). The GlycA NMR signal, at 2.00 +/- 0.01 ppm in the NMR spectrum, is derived from the N-acetyl methyl group protons within the carbohydrate side chains of circulating glycoproteins such as alpha 1-acid glycoprotein, haptoglobin, alpha 1-antitrypsin, alpha 1-antichymotrypsin, and transferrin. GlycA levels were then compared between AP patients and controls, as well as within the AP group, based on etiology and severity. Results: Demographic comparisons were similar, except for a higher BMI in AP patients compared to healthy controls (29.9 vs. 24.8 kg/m(2); p < 0.001). AP was mild in 10 patients, moderate in 7, and severe in 3. GlycA levels were higher in AP patients than healthy controls on admission (578 vs. 376 mu mol/L, p < 0.001) and at discharge (655 vs. 376 mu mol/L, p < 0.001). GlycA levels were significantly higher in patients with moderate-severe AP than in those with mild AP at discharge (533 vs. 757 mu mol/L, p = 0.023) but not at admission. After adjusting for BMI, multivariable regression indicated that patients with GlycA levels > 400 mu mol/L had significantly higher odds of having AP of any severity (OR = 6.88; 95% CI, 2.07-32.2; p = 0.004) and mild AP (OR = 6.12; 95% CI, 1.48-42.0; p = 0.025) than controls. Conclusion: Our pilot study highlights the use of GlycA as a novel diagnostic biomarker of inflammation in patients with AP. Our study shows that GlycA levels were significantly higher in hospitalized AP patients compared to healthy controls. Patients with moderate-to-severe AP had higher GlycA levels compared to patients with mild AP at the time of their hospital discharge, suggesting persistent inflammation in patients with severe disease.