Urinary 8-oxo-7,8-dihydroguanosine as a potential biomarker of frailty for elderly patients with cardiovascular disease

Y.D. Liang, Q. Liu, M.H. Du, Z. Liu, S.M. Yao, P.P. Zheng, Y.H. Wan, N. Sun, Y.Y. Li, J.P. Liu, Y. Luo, J.P. Cai, J.F. Yang, H. Wang

Free Radic Biol Med. 2020 Mar 23;152:248-254. doi: 10.1016/j.freeradbiomed.2020.03.011. [Epub ahead of print]

The diagnosis of frailty is usually subjective, which calls for objective biomarkers in clinical medicine. 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGsn) and 8-oxo-7, 8-dihydroguanosine (8-oxoGsn) in urine are two aging biomarkers that have not been explored deeply in cases of frailty.

A total of 508 elderly patients with cardiovascular disease (mean age 75.0 ± 6.5 years, 50.8% males) were enrolled consecutively. Frailty was assessed by the Fried phenotype (robust: 0 score; pre-frail: 1-2 scores; frail: 3-5 scores). The concentrations of 8-oxoGsn and 8-oxodGsn in urine were measured by improved ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). Urinary creatinine (Cre) was tested to correct the 8-oxoGsn and 8-oxodGsn levels.

According to the Fried phenotype score, the proportions of robust, pre-frail, and frail subjects were 20.5% (104/508), 53.9% (274/508), and 25.6% (130/508), respectively. The urinary 8-oxoGsn/Cre (P < 0.001) differed significantly among these 3 groups, but the urinary 8-oxodGsn/Cre (P = 0.600) showed no marked difference. Univariate and multivariate logistic regression showed that the age (odds ratio [OR] = 1.090, P < 0.001), systolic blood pressure (OR = 0.981, P = 0.008), 8-oxoGsn/Cre (OR = 1.203, P = 0.007), hemoglobin (OR = 0.980, P = 0.007), and sodium (OR = 0.915, P = 0.044) were independently associated with frailty. The sensitivity and specificity to identify frailty were 53.08% and 71.96%, respectively, for 8-oxoGsn/Cre at the optimal cut-off value of 3.879 μmol/mol according to the maximal Youden index.  

Comment:  Urinary 8-oxoGsn, as a recognized biomarker of RNA oxidation, is independently associated with frailty in elderly patients with cardiovascular disease. However, the urinary 8-oxodGsn shows no obvious correlation with frailty. To obtain a better diagnostic performance for frailty, more biomarkers from different pathophysiological pathways should be explored in the future.