Background: Acute intermittent porphyria (AIP) is an autosomal inherited disease caused by deficiency of the third enzyme in the heme biosynthetic pathway, porphobilinogen deaminase. The clinical course of the disease is characterized by acute attacks, most often with abdominal pain.The aim of our study was to investigate selected markers of oxidative and carbonyl stress in plasma and saliva in patients with AIP and to find out whether saliva could be used for monitoring the disease progression. Saliva is an attractive biological fluid for determination of biochemical markers in various pathological conditions. The advantage is that saliva can be collected non-invasively, and the examination needs only a small volume of saliva.
Methods: Blood and total non-stimulated saliva were collected from 16 patients with AIP in remission, and from 20 healthy individuals. Markers of oxidative and carbonyl stress - advanced glycation end products (AGEs), and thiobarbituric acid reacting substances (TBARS) were determined by spectrofluorometric methods, advanced oxidation protein products (AOPPs), total antioxidant capacity (TAC) and ferric reducing ability of plasma/saliva (FRAP/FRAS) were investigated by spectrophotometric methods in the above mentioned groups.
Results: Advanced glycation end products and thiobarbituric acid reacting substances in plasma and saliva were significantly higher in patients with AIP in comparison to the control group (p < 0.001) and (p < 0.05). Advanced oxidation protein products in AIP if compared to the control group did not show statistical significance (p > 0.05), but the levels in the saliva were significantly lower (p < 0.001). The concentrations of markers of antioxidant status of plasma and saliva were significantly lower in AIP if compared to the control group (p < 0.001).
Conclusions: According to the best of our knowledge this is the first study to demonstrate increased concentrations of markers of oxidative and carbonyl stress and decreased antioxidant status of plasma and saliva in patients with AIP. Moreover, the study suggests that the saliva might be a promising fluid to study relevant biomarkers in a wide array of human biomedical conditions.Key words: acute intermittent porphyria - biomarkers - oxidative and carbonyl stress - plasma and saliva.