The association of serum inflammatory biomarkers with chronic kidney disease in hypertensive patients

A positive association between inflammation and chronic kidney disease (CKD) has been reported but the impact of hypertension on this relation remains unclear. The aim of this study is to investigate the association of various inflammation markers with risk of CKD in hypertensive patients. 387 hypertensive patients (mean age 55.5 years) were recruited. Serum matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1(TIMP-1), high-sensitivity C-reactive protein (hsCRP) and osteopontin (OPN) were measured by ELISA. CKD was diagnosed either as evidence of kidney damage, including microalbuminuria, or by low glomerular filtration rate (GFR) (<60 mL/min/1.73m(2)), which was estimated using the Modification of Diet in Renal Disease (MDRD) abbreviated equation. Compared with the reference groups (eGFR >= 60 mL/min/1.73m(2)), the serum levels of TIMP-1, OPN, hsCRP were significantly higher, and the MMP-9/TIMP-1 ratio was lower in the risk group (eGFR <60 mL/min/1.73 m(2)). Multiple logistic regression analysis showed that TIMP-1, MMP-9/TIMP-1 ratio, OPN and hsCRP were associated with low GFR separately after adjustment, whereas MMP-9/TIMP-1 ratio, OPN and hsCRP were associated with microalbuminuria. The significant association of MMP-9/TIMP-1 ratio and OPN with low GFR and microalbuminuria persisted after additional adjustment for other studied inflammatory biomarkers. Our data suggest that inflammation is strongly and independently associated with renal damage in hypertensive patients. MMP-9/TIMP-1 ratio and OPN may serve as novel risk factors and therapeutic targets for the treatment of CKD in hypertensive patients.