The impact of chronic untreated hyperglycaemia on the long-term stability of paraoxonase 1 (PON1) and antioxidant status in human sera

Abstract

Aims Paraoxonase 1 (PON1) is increasingly measured on samples that have been stored for extended durations. The impact of storage and baseline conditions on the stability of the enzyme is however not well documented. We investigated the influence of hyperglycaemia on the stability of PON1 activity and antioxidant status in human sera stored for 12 months. Methods Blood was collected from 60 individuals aged 35–80 years with chronic hyperglycaemia (HbA1c≥6.5%) or normoglycaemia (HbA1c<6.5%) in Cape Town. At baseline and after 12 months at −80°C, levels of PON1 activity ( paraoxoase and arylesterase), antioxidant activity (ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC)) and lipid peroxidation (malondialdehyde and oxidised low density lipoprotein (ox-LDL)) were measured and compared.