Urinary RBP and NGAL Levels are Associated with Nephropathy in Patients with Type 2 Diabetes.

The diagnosis of type 2 diabetic nephropathy (T2DN) patients is important to prevent the long-term damaging effects of kidney loss in patients with diabetes and is decisive for patient outcomes. The aim of this study was to explore urine retinol binding protein (RBP) and neutrophil gelatinase-associated lipocalin (NGAL) in T2DN patients with and without albuminuria. A total of 293 T2DN patients were divided into three groups according to their urine albumin/urine creatinine ratio (UACR): normoalbuminuria group (UACR<30 mg/g, n=100), microalbuminuria group (UACR 30-300 mg/g, n=100) and macroalbuminuria group (UACR>300 mg/g, n=93); 50 non-diabetic subjects were recruited as the control group. The levels of urine RBP, NGAL, TNF-α and IL-18 in T2DN patients and non-diabetic subjects were measured using ELISA assays. We first analyzed the clinical characteristics of the control and T2DN groups and found that urine NGAL, RBP, TNF-α and IL-18 levels were significantly increased and significantly correlated with the degree of albuminuria. In addition, univariate linear regression analysis showed that urine RBP was associated with UACR, BMI, Scr, BUN, TG, disease duration, SBP, NGAL, TNF-α and IL-18 levels, and urine NGAL was positively correlated with UACR, Scr, BUN, RBP, TNF-α and IL-18 levels. The results indicate that urine levels of NGAL and RBP may be independently associated with albuminuria in T2DN and may serve as novel biomarkers for the identification of T2DN.

Wu J ，Shao X ，Lu K ，Zhou J ，Ren M ，Xie X ，Liu J ，Xu Y ，Ding Y ，Shen X ，Zhu C ... -  《-》

Urinary NGAL and RBP Are Biomarkers of Normoalbuminuric Renal Insufficiency in Type 2 Diabetes Mellitus.

As a screening index of diabetic kidney disease (DKD), urinary albumin/creatine ratio (UACR) is commonly used. However, approximately 23.3%-56.6% of DKD patients with estimated glomerular filtration rate (eGFR) < 60 ml/min per 1.73 m2 are normoalbuminuric. Thus, urinary biomarkers of nonalbuminuric renal insufficiency in type 2 diabetes mellitus (T2DM) patients are urgently needed. This cross-sectional study enrolled 209 T2DM patients with normoalbuminuria whose diabetes duration was more than 5 years. The patients were classified into two groups, NO-CKD (eGFR ≥ 60 ml/min per 1.73 m2, n = 165) and NA-DKD (eGFR < 60 ml/min per 1.73 m2, n = 44). Levels of urinary neutrophil gelatinase-associated lipocalin (NGAL), retinol-binding protein (RBP), plasminogen activator inhibitor-1 (PAI-1), vascular cell adhesion molecule-1 (VCAM-1), and E-cadherin were detected, and their correlations with eGFR, plasma TNF-α, IL-6, endothelin-1 (ET-1), and 8-hydroxydeoxyguanosine (8-OHdG) were assessed. Among patients with renal insufficiency, 26.0% was normoalbuminuric. Compared to the NO-CKD group, the NA-DKD group was older with lower hemoglobin (HB) levels and higher systolic blood pressure (SBP), plasma TNF-α, IL-6, and 8-OHdG levels. Logistic regression analysis suggested that age, TNF-α, and 8-OHdG were independent risk factors for nonalbuminuric renal insufficiency. Compared to the NO-CKD group, the NA-DKD group exhibited significant increases in urinary NGAL and RBP levels but not PAI-1, VCAM-1, and E-cadherin. Urinary NGAL and RBP both correlated negatively with eGFR and positively with plasma IL-6 and 8-OHdG. Multiple linear regression indicated NGAL (β = -0.287, p = 0.008) and RBP (β = -44.545, p < 0.001) were independently correlated with eGFR. Age, plasma TNF-α, and 8-OHdG are independent risk factors for renal insufficiency in T2DM patients with normoalbuminuria. Urinary NGAL and RBP can serve as noninvasive biomarkers of normoalbuminuric renal insufficiency in T2DM.

Li A ，Yi B ，Liu Y ，Wang J ，Dai Q ，Huang Y ，Li YC ，Zhang H ... -  《-》

The changes of serum sKlotho and NGAL levels and their correlation in type 2 diabetes mellitus patients with different stages of urinary albumin.

To investigate the changes of serum anti-aging protein Klotho and neutrophil gelatinase-associated lipocalin (NGAL) levels and their correlation in type 2 diabetes mellitus (T2DM) patients at different stages of diabetic kidney disease (DKD) determined by urinary albuminuria. 462 cases with T2DM were divided into three groups: normoalbuminuric [N-UAlb; urinary albumin to creatinine ratio (UACR) < 30 mg/g, n=180], microalbuminuric [M-UAlb; UACR 30-300 mg/g, n = 158], macroalbuminuric [L-UAlb; UACR > 300 mg/g, n = 124]. The levels of serum soluble-Klotho (sKlotho), NGAL, 8-isoprostane prostaglandin F2α (8-iso-PGF2α), monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1) were determined by enzyme-linked immunosorbent assay (ELISA) in all cases and 160 control subjects. Compared with control, serum sKlotho levels were significantly decreased (P < 0.001), and serum NGAL levels increased significantly (P < 0.001) in T2DM patients. Furthermore, serum sKlotho and NGAL levels were significantly negatively correlated (P < 0.001). Serum sKlotho levels negatively correlated with UACR, TG, CHO, LDL, 8-Iso-PGF2α, MCP-1, TNF-α, TGF-β1 (P < 0.001), but positively correlated with LDL (P < 0.001). Serum NGAL levels positively correlated with UACR, 8-Iso-PGF2α, MCP-1, TNF-α, TGF-β1 (P < 0.001). In addition, serum NGAL levels and LDL were significantly positively correlated (P = 0.005), and HDL was significantly negatively correlated (P < 0.001). Serum Klotho and NGAL levels may become new biomarkers of the early diagnosis of DKD in T2DM. Klotho may participate in the development of DKD pathological mechanism such as oxidative stress related to inflammation, renal fibrosis, lipid metabolic disorders, modulating the pathological process of diabetic kidney tissue. NGAL may play a part in these mechanisms.

Wu C ，Wang Q ，Lv C ，Qin N ，Lei S ，Yuan Q ，Wang G ... -  《-》

Utility of urinary biomarkers as a diagnostic tool for early diabetic nephropathy in patients with type 2 diabetes mellitus.

Renal tubulo-interstitial damage has an important role in the pathogenesis of early diabetic nephropathy. Urinary biomarkers can help in the detection of early nephropathy in type 2 diabetic patients. The aim of this study was to estimate the levels of urinary neutrophil gelatinase associated lipocalin (NGAL) and cystatin-C in type 2 diabetic patients with early diabetic nephropathy & to compare them with diabetic patients without nephropathy and to correlate urinary NGAL and cystatin-C levels with microalbuminuria in them. Cross-sectional comparative study. The study was conducted on 126 patients with type 2 diabetes along with 30 control subjects attending the outpatient care department of a tertiary care teaching hospital. There were 3 study groups-diabetic patients with microalbuminuria, diabetic patients without albuminuria and control subjects who were non-diabetic without any renal disease. Details on duration of diabetes and glycemic status were obtained from the patients. Urine examination was done for subjects in all the groups to look for microalbuminuria along with estimation of NGAL and cystatin-C levels. Samples were stored at -20 °C in the deep freezer. Urinary NGAL and cystatin-C levels were significantly elevated in patients with microalbuminuria (228.18 & 3.23 ng/ml) as compared to those without albuminuria (146.12 & 2.61 ng/ml) and in control subjects (26.56 & 0.30 ng/ml). Urinary NGAL and cystatin-C levels showed a linear correlation with microalbuminuria in diabetic patients. Urinary NGAL and cystatin-C levels were increased in type 2 diabetic patients with early diabetic nephropathy as compared to patients without nephropathy. Urine NGAL and cystatin-C levels also showed a positive correlation with microalbuminuria (urine albumin-creatinine ratio) in patients with type 2 diabetes mellitus.

Vijay S ，Hamide A ，Senthilkumar GP ，Mehalingam V ... -  《-》

Assessing urinary levels of IL-18, NGAL and albumin creatinine ratio in patients with diabetic nephropathy.

Diabetic nephropathy (DN) is a serious microvascular complication of a longstanding hyperglycemia. This study aims to evaluate whether urinary neutrophil gelatinase-associated lipocalin (NGAL) and urinary Interleukin-18 possess a better diagnostic value than albumin creatinine ratio in assessing the severity of nephropathy in patients with type 2 diabetes mellitus (T2DM). Ninety participants diagnosed with T2DM were recruited and they were divided into three study groups according to their albumin/creatinine ratio (ACR): (Normoalbuminuria group, Microalbuminuria group, and Macroalbuminuria group). A matching of Ninety healthy subjects were included as controls. Blood and urine samples were collected to measure various markers of glycemic control and kidney function. IL-18 levels were not changed significantly between all study groups (P > 0.05), despite a significant positive correlation between IL-18 and urinary albumin levels. NGAL levels were significantly increased in Microalbuminuria group and Macroalbuminuria group as compared to the control and Normoalbuminuria groups. NGAL was also positively correlated with urinary albumin and ACR, but negatively correlated with the age and body mass index. Receiver Operating Characteristic curves revealed that for early detection of DN, the best cutoff values to discriminate DN and diabetic without nephropathy groups were ˃ 21.4 ng/ml for NGAL (94.67 sensitivity, 26.67% specificity), ≤0.34 pg/mL for IL-18 (72% sensitivity, 53.33% specificity), and ˃29.8 mg/g for ACR (80% sensitivity, 100% specificity). We conclude that the urinary ACR is a more accurate individual biomarker of DN when compared to both NGAL and IL-18.

Sueud T ，Hadi NR ，Abdulameer R ，Jamil DA ，Al-Aubaidy HA ... -  《-》