Recent cross-sectional and longitudinal studies indicate that measurements of peripheral blood carbonyl stress markers such as the
advanced glycation end product (AGE)
pentosidine and the reactive carbonyl-detoxifying B6
vitamin pyridoxal could be used as therapeutic
biological markers in subpopulations of
schizophrenia patients.
Glyceraldehyde-derived AGEs (Glycer-AGE) have strong neurotoxicity, and soluble receptors for AGEs (sRAGE) may ameliorate the effects of AGEs. In the present study, we measured Glycer-AGEs and sRAGE levels to determine their potential as diagnostic, therapeutic, or clinical
biological markers in patients with
schizophrenia. After enrollment of 61 admitted Japanese patients with acute
schizophrenia and 39 healthy volunteers, 54 patients were followed up from the acute stage to remission. Serum
biomarkers were measured in blood samples taken before breakfast using competitive
enzyme-linked
immunosorbent assays, and Glycer-AGEs were significantly higher and sRAGE levels were significantly lower in patients with acute
schizophrenia than in healthy controls. Glycer-AGEs/sRAGE ratios were also higher in
schizophrenia patients and were stable during the
clinical course. Furthermore, discriminant analyses confirmed that Glycer-AGEs and Glycer-AGEs/sRAGE ratios are significant diagnostic markers for
schizophrenia, and distinguished between patients and healthy controls in 70.0% of cases. However, these markers of carbonyl stress were not correlated with clinical features, including disease severity, or with daily
chlorpromazine doses. These data indicate the potential of Glycer-AGEs, RAGEs, and their relative ratios as diagnostic markers for patients with
schizophrenia.