MMP9 and chronic kidney disease: evaluated the correlation between serum inflammatory markers and CKD in hypertensive patients and showed that the matrix metalloproteinase-9(MMP-9)/tissue inhibitor of metalloproteinase-1(TIMP-1) ratio and osteopontin (OPN) were associated with CKD in hypertensive patients [6], suggesting that the measurement of these biomarkers may provide important information about CKD in hypertensive patients.