Diagnostic value of cystatin C for diagnosis of early renal damages in type 2 diabetic mellitus patients: The first experience in Iran

Iran diabetes research study; knowledge discovery in diagnosis: a scoping review

Introduction

The rising prevalence of diabetes shows high health and socio-economic burdens. Therefore, the development and evaluation of new diagnostic methods may improve the detection of disease and its complications in the early stages. This study aimed to analyze the scope of the studies related to diabetes diagnosis.

Material and method

Publications from January 2015 until December 2019 (5 years) were searched with keywords of (diabetes OR diabetic) AND (Iran) in Scopus and PubMed databases. All data were reviewed by two reviewers and the included publications were categorized based on the subjects, study design, and publication year.

Results

Based on the selected criteria, 103 articles were included. The highest number of publications was observed in 2019. The trend of publication was slightly increased during the study period (2015-2019). Case-control and cross-sectional studies were the most common type of study design used in the included documents. Publications in the field of diagnostic models, biomarkers, and biosensors from 2015 to 2019 showed an increasing trend compared to others subjects.

Discussion and conclusion

Studies about proper diabetes diagnostic procedures such as new diagnostic techniques, using diagnostic models, and evaluation of new diagnostic biomarkers in Iran are remarkably increased. However, more original and review studies are needed to improve scientific methods in the field of early detection of diabetes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00843-x.

Evaluation of early biomarkers of renal dysfunction in diabetic patients

Objectives:

To evaluate 2 renal tubular enzymes; urinary neutrophil gelatinase-associated lipocalin (uNGAL), and urinary N-acetyl-beta-D-glucosaminidase (uNAG), and serum Cystatin C as candidate biomarkers for early diagnosis of early stage of diabetic nephropathy (DB) in patients with type 2 diabetes mellitus (T2DM).

Methods:

This cross-sectional study was carried out at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia during the period between May 2017 and May 2018 and was conducted on 86 patients with T2DM. Patients were classified according to their albumin/creatinine ratio (ACR) into 3 groups; a normal albuminuria group with ACR <30 mg/g creatinine, a moderately increased albuminuria group with ACR: 30-299 mg/g creatinine, and a severely increased albuminuria group with ACR ≥300 mg/g. Healthy adults were recruited as a control group. Urine uNGAL, uNAG, and serum Cystatin C were measured in all patients.

Results:

Compared with healthy control, diabetic patients with normal albuminuria excreted significantly higher levels of uNGAL (p<0.001). In addition, significantly elevated uNGAL, uNAG and cystatin C levels were observed in moderately increased albuminuria and severely increased albuminuria groups when compared to the control and normoalbuminuric groups (p<0.001). urinary neutrophil gelatinase-associated lipocalin, urinary N-acetyl-beta-D-glucosaminidase and Cystatin C showed a positive correlation with fasting blood glucose (FBG), HbA1c, duration of diabetes, urea, creatinine, and ACR.

Conclusion:

Our results indicated that uNGAL could be a sensitive biomarker for early renal dysfunction in diabetic patients while uNAG and serum Cystatin C might have prognostic value.

Salivary and serum cystatin SA levels in patients with type 2 diabetes mellitus or diabetic nephropathy

OBJECTIVE

To investigate putative salivary biomarkers for screening and diagnosis of type 2 diabetes mellitus and diabetic nephropathy.

DESIGN

Saliva and serum samples were collected from 29 patients with type 2 diabetes, 20 patients with diabetic nephropathy, eight patients with non-diabetic induced nephropathy, and 25 healthy subjects. Initially, pooled unstimulated saliva samples from six sex- and age-matched healthy subjects and six patients with type 2 diabetes were subjected to two-dimensional gel electrophoresis, followed by mass spectrometry. Protein expression of cystatin SA in the saliva of patients with type 2 diabetes was further examined in saliva and serum using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Two-dimensional gel electrophoresis revealed upregulation of salivary cystatin SA in patients with type 2 diabetes. ELISA showed a weak trend of increasing salivary cystatin SA levels in patients with type 2 diabetes, compared with those levels in healthy subjects. When patients were stratified according to periodontal status, linear regression analyses revealed that salivary cystatin SA levels were associated with Periodontal Screening and Recording (PSR) index (β = 0.297, p <  0.05) when the analysis was adjusted for age, sex, HbA_1C, estimated glomerular filtration rate (eGFR), and number of teeth. Serum cystatin SA levels were negatively associated with eGFR (β = -0.534, p <  0.0001) when the analysis was adjusted for age, sex, HbA_1C, number of teeth, and PSR index.

CONCLUSIONS

Salivary cystatin SA was associated with periodontal disease severity; moreover, serum cystatin SA levels could reflect kidney function.

Meta-analysis of the efficacy of liraglutide in patients with type 2 diabetes accompanied by incipient nephropathy

The efficacy of liraglutide in patients with type 2 diabetes accompanied by early-stage nephropathy has remained to be fully elucidated. The present meta-analysis was performed to determine the clinical outcomes associated with liraglutide treatment. The PubMed, Ovid, Cochrane Library, Chinese National Knowledge Infrastructure and Wanfang databases were searched in October 2018 to identify randomized controlled trials of liraglutide for diabetes patients with early-stage nephropathy. The treatment effect was estimated by calculating the mean difference (MD). Heterogeneity was assessed using χ² and I² tests. In addition, risk of bias graphs and summaries were used to assess the quality of the trials included. A total of 13 randomized controlled trials were included in the present meta-analysis. In subjects with stage I–II diabetic nephropathy (DN), liraglutide had obvious advantages in lowering the urinary albumin-to-creatinine ratio [UACR; MD=−90.96, 95% confidence interval (CI)=−94.12 to −87.80, P<0.00001], urinary albumin excretion rate (UAER; MD=−64.86, 95% CI=−66.63 to −63.08, P<0.00001), serum creatinine (Scr; MD=−13.67, 95% CI=−17.88 to −9.46, P<0.00001). In subjects with stage-III DN, liraglutide had favorable effects on renal function (UACR: MD=−11.23, 95% CI=−13.14 to −9.32, P<0.00001; UAER: MD=−14.06; 95% CI=−6.93 to −11.18; P<0.00001; Scr: MD=−9.17, 95% CI=−14.61 to −3.72, P=0.0010) and exhibited anti-inflammatory effects (transforming growth factor-β1: P<0.00001; tumor necrosis factor-α: P=0.006; interleukin-6: P<0.00001). Furthermore, liraglutide also reduced the blood lipid levels, body mass index and post-prandial blood glucose. The most common adverse effects of liraglutide were gastrointestinal tract reactions and hypoglycemia, but these symptoms resolved quickly. Liraglutide appears to be effective in reducing proteinuria, improving renal function, producing an anti-inflammatory effect and ameliorating glucose and lipid metabolism in diabetic patients with early-stage nephropathy.

Meta-analysis of the benefit of sitagliptin treatment in patients with type 2 diabetes complicated with incipient nephropathy

The purpose of this meta-analysis was to evaluate the evidence of the clinical efficacy and safety of sitagliptin in diabetic patients with incipient nephropathy. PubMed, Ovid, Cochrane library, Chinese National Knowledge Infrastructure, and Wanfang databases were searched in September 2017 to identify randomized controlled trials (RCTs) of sitagliptin in diabetic patients with incipient nephropathy. Study selection, data extraction and study quality assessment were performed independently by two investigators, while disagreements were resolved by a third reviewer. The treatment effect was estimated by calculating the mean difference (MD) or standard mean difference (SMD). Heterogeneity was assessed with the χ² and I² tests. Additionally, risk of bias graphs and summaries were used to assess the quality of the included trials. Thirteen RCTs were included in this review; their results suggested that sitagliptin has obvious advantages in lowering the 24-hour urinary albumin excretion [MD, -25.71; 95% confidence interval (CI), -30.75 to -20.66; P<0.00001], serum cystatin C (MD, -0.59; 95% CI, -0.64 to -0.54; P<0.00001), inflammation (MD, -0.81; 95% CI, -1.20 to -0.42; P<0.0001), and total cholesterol (MD, -0.13; 95% CI, -0.22 to -0.03; P=0.009). However, sitagliptin did not appear to influence serum creatinine, fasting blood glucose, postprandial blood glucose, glycosylated hemoglobin A1c, or triglyceride levels, although these results may have been influenced by biases in the included trials. The most common adverse effects of sitagliptin were gastrointestinal tract reaction and hypoglycemia, although these symptoms resolved quickly. Sitagliptin appears to be effective in reducing proteinuria, ameliorating renal function, and producing an anti-inflammatory effect in patients with early-stage diabetic nephropathy. The present analysis provides important guidance for the clinical application of sitagliptin.

Retinol-binding protein 4 versus albuminuria as predictors of estimated glomerular filtration rate decline in patients with type 2 diabetes

Background

Since the increase in some tubular damage biomarkers can be observed at the early stage of diabetic nephropathy, even in the absence of albuminuria, we aimed to investigate if urinary albumin is superior than tubular damage marker, such as serum retinol-binding protein 4 (RBP4), in predicting renal function decline (defined as estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m²) in the cohort of patients with type 2 diabetes mellitus (T2D).

Materials and Methods

A total of 106 sedentary T2D patients (mean [± standard deviation] age 64.9 [±6.6] years) were included in this cross-sectional study. Anthropometric and biochemical parameters (fasting glucose, glycated hemoglobin [HbA1c], lipid parameters, creatinine, RBP4, high sensitivity C-reactive protein [hsCRP], urinary albumin excretion [UAE]), as well as blood pressure were obtained.

Results

HsCRP (odds ratio [OR] =0.754, 95% confidence interval [CI] (0.603-0.942), P = 0.013) and RBP4 (OR = 0.873, 95% CI [0.824-0.926], P < 0.001) were independent predictors of eGFR decline. Moreover, although RBP4 and UAE as single diagnostic parameters of renal impairment showed excellent clinical accuracy (area under the curve [AUC] = 0.900 and AUC = 0.940, respectively), the Model which included body mass index, HbA1c, triglycerides, hsCRP, and RBP4 showed statistically same accuracy as UAE, when UAE was used as a single parameter (AUC = 0.932 vs. AUC = 0.940, respectively; P for AUC difference = 0.759). As well, the Model had higher sensitivity and specificity (92% and 90%, respectively) than single predictors, RBP4, and UAE.

Conclusion

Although serum RBP4 showed excellent clinical accuracy, just like UAE, a combination of markers of tubular damage, inflammation, and traditional markers has the higher sensitivity and specificity than UAE alone for prediction renal impairment in patients with T2D.

The ZDSD rat: a novel model of diabetic nephropathy

The ZDSD rat is a new obese-diabetic rat model that expresses type 2 diabetes in the presence of an intact leptin pathway. During a long pre-diabetic state, the animals exhibit most of the features of metabolic syndrome including obesity, hyperlipidemia, hypertension, insulin resistance and decreased glucose disposal. The animals used in these studies were either allowed to become spontaneously diabetic at 16-30 weeks of age, or diabetes was induced with a diabetogenic diet. In the presence of either spontaneous or diet-induced diabetes, they develop progressive albuminuria as well as increases in other urinary markers of impaired renal function (kidney injury molecule-1 (KIM-1), β2-microglobulin, clusterin and cystatin C). Typical morphological changes of nephropathy, such as glomerular capillary basement membrane thickening and podocyte effacement, accompany these marker increases. Lisinopril (ACEi) treatment (30 mg/kg/day via the diet) dramatically reduced diabetes-induced albuminuria by 85%, independent of the duration of diabetes or the initial albumin excretion. These results position the ZDSD rat as a relevant model of diabetic nephropathy that can be treated with clinically effective compounds.