Distribution pattern of urine albumin creatinine ratio and the prevalence of high-normal levels in untreated asymptomatic non-diabetic hypertensive patients

β-Amyrin ameliorates diabetic nephropathy in mice and regulates the miR-181b-5p/HMGB2 axis in high glucose-stimulated HK-2 cells

Diabetic nephropathy (DN) is a diabetic complication that can cause renal failure. β-amyrin has been identified to possess anti-diabetic property. This study was designed to evaluate the potential role of β-amyrin in DN and its underlying mechanism. Streptozotocin-induced diabetic mice were used as the in vivo model, and high glucose (HG)-stimulated human proximal tubular HK-2 cells were utilized as the in vitro model. Renal histological changes in mice were assessed by hematoxylin-eosin and periodic acid-Schiff staining. HK-2 cell viability and apoptosis were detected by Cell Counting Kit-8 assay and flow cytometry analysis, respectively. β-amyrin was found to ameliorate kidney injury in DN mice and suppressed inflammatory response as well as apoptosis of HG-stimulated HK-2 cells. miR-181-5p expression in murine renal tissues and HK-2 cells was detected by in situ hybridization (ISH) and fluorescence in situ hybridization (FISH). MiR-181b-5p, a previously identified target for diabetic kidney disease, was downregulated in renal tissues and HG stimulated HK-2 cells, and β-amyrin induced the upregulation of miR-181b-5p. Binding relationship between miR-181b-5p and high mobility group box 2 (HMGB2) was confirmed by luciferase reporter assay. MiR-181b-5p bound to 3' untranslated region of HMGB2 to suppress its expression. As shown by immunohistochemical staining and immunofluorescence staining, HMGB2 was upregulated in the in vivo and in vitro models of DN, and β-amyrin induced the downregulation of HMGB2. Moreover, HMGB2 overexpression neutralized the suppressive effects of miR-181b-5p elevation on the inflammatory response and apoptosis of HG-treated HK-2 cells. Overall, β-amyrin ameliorates DN in mice and suppresses inflammatory response and apoptosis of HG-stimulated HK-2 cells via the miR-181b-5p/HMGB2 axis.

Microalbuminuria in subjects with hypertension attending specialist blood pressure clinics

Albuminuria is associated with increased risk of cardiovascular disease and target organ damage in patients with diabetes mellitus. In nondiabetic hypertensive patients, the threshold at which microalbuminuria (MAU) increases risk is unclear and there is evidence that cardiovascular risk may be increased in individuals with MAU levels lower than the usual recommended screening thresholds. We compared two definitions of MAU (on the basis of three early morning urine samples) in a cohort of hypertensive patients attending two specialist clinics in Scotland: conventional (MAU(C)) albumin-to-creatinine ratio (ACR) >2.5-25 mg mmol(-1) in males or >3.5-25 mg mmol(-1) in females; and low-grade (MAU(L)) ACR 1.2-2.5 in males or 1.7-3.5 mg mmol(-1) in females. Of the 1059 subjects screened, 786 (74%) were nondiabetic, with estimated glomerular filtration rate ⩾30 ml min(-1) per 1.73 m(2) and without gross proteinuria (low-risk subset). The average age was 58±15 years, body mass index 30±6 kg m(-2) and 46% were males. The prevalence of MAU(C) was 11% and 9.5% in the overall and low-risk subset, respectively, whereas MAU(L) prevalence was 11.1% and 10% respectively. The prevalence of cardiovascular disease was higher (24%) with albuminuria (both MAU(C) and MAU(L)) compared with 14% among those without albuminuria. The use of MAU(L) doubled the number of hypertensive subjects with increased cardiovascular risk who can be targeted for more rigorous risk reduction strategies. Consideration should be given to reducing the current threshold for MAU.

The prevalence, characteristics, and clinical significance of abnormal albuminuria in patients with hypertension

Kidney function and cardiovascular disease are closely connected and albuminuria is a proven marker of cardiovascular risk. The present study investigated the prevalence and characteristics of albuminuria in patients with hypertension. Outpatients with essential hypertension under medical treatment were enrolled in this study (n = 350, 70.0 ± 11.4 years old). Urine samples were collected for the measurement of albumin concentration, which are expressed as the ratio of urine albumin to creatinine concentration (mg/g Cr). Cross-sectional analyses were also performed of the relationships between urinary albumin and other variables. Urinary albumin was detected in 88.3% of patients, while only 35.4% showed abnormal albuminuria (≥30 mg/g Cr). The presence of abnormal albuminuria was independently correlated with systolic blood pressure, B-type natriuretic peptide, and C-reactive protein by multivariate analysis (P < 0.05). Furthermore, multivariate regression analysis identified systolic blood pressure, serum creatinine, B-type natriuretic peptide, and C-reactive protein as the only factors showing independent correlation with urinary albumin (P < 0.05). Thus, approximately 35% of hypertensive patients had abnormal albuminuria. Urinary albumin was closely associated with blood pressure, C-reactive protein, and B-type natriuretic peptide, indicating that the severity of albuminuria parallels that of systemic inflammation, cardiac load, and blood pressure.