Diagnostic value of serum cystatin C for diabetic nephropathy: a meta-analysis

BACKGROUND

Although dozens of studies have investigated the relationship between the content of serum cystatin C (Cys-C) and diabetic nephropathy (DN), the results are still controversial. Hence, This study aims to explore the accuracy of serum Cys-C for diagnosing DN by meta-analysis.

METHODS

The studies about serum Cys-C diagnosing DN were searched from six online databases from inception to September 22, 2020. The data were processed by Stata 15.0 statistic software. The corresponding diagnostic effect sizes, such as sensitivity and specificity, were obtained. We drew a summary receiver operating characteristic (SROC) curve. We assess the risk of literature bias was following the QUADAS-2 guidelines.

RESULTS

Twenty-six published studies were identified. The results showed a pooled sensitivity of 0.86 (95% confidence interval (CI): 0.82-0.90), specificity of 0.89 (95%CI: 0.85-0.92), positive likelihood ratio of 7.59 (95%CI: 5.66-10.19), negative likelihood ratio of 0.16 (95%CI: 0.12-0.21), and diagnostic odds ratio of 48.03 (95%CI: 30.64-75.29). The area under the SROC curve was given a value of 0.94 (95%CI: 0.91-0.96).

CONCLUSION

Serum cystatin C has an excellent diagnostic value with good sensitivity and specificity for diabetic nephropathy.

Preference between serum homocysteine and urinary periostin as early predictive biomarkers of renal dysfunction among uncontrolled diabetics

OBJECTIVES

Type 2 diabetes mellitus (T2DM) represents a serious public health problem. Environmental toxins, other than infectious agents or exposures can stimulate immune responses which are associated with the occurrence of T2DM. Diabetic nephropathy (DN) is a serious complication of diabetes that leads to changes in the structure and function of the kidneys. The study aimed to detect diagnostic biomarkers for (DN), at an early stage, to prevent disease progression in these patients and improve their outcomes.

METHODS

This study was performed on 102 T2DM patients and 80 normal controls. Blood glucose, HbA_1c, serum homocysteine (Hcy) and urinary periostin were assessed. Patients were divided into: controlled (n=46) (HbA_1c <6.5%) and uncontrolled diabetics (n=56) (HbA_1c >6.5%).

RESULTS

The study results revealed a significant rise in blood glucose and HbA_1c as well as serum Hcy levels in diabetic groups compared to controls. Also, urinary periostin exhibited significant elevation in diabetic groups. Serum glucose, HbA_1c and serum Hcy revealed a highly significant difference between diabetic subgroups and control groups, while urinary periostin demonstrated a non-significant difference. Only, urinary periostin showed a significant increase in uncontrolled diabetics.

CONCLUSIONS

The highest levels of serum Hcy and urinary periostin were recorded only in the uncontrolled diabetics. Urinary periostin was demonstrated as a more preferable biomarker being a non-invasive sample for predicting renal insult in diabetic subjects. This biomarker could be performed regularly for early detection of DN. Also, it could be added to the periodic medical examinations of workers occupationally exposed to workplace pollutants inducing diabetes.

Serum Cystatin C Trajectory Is a Marker Associated With Diabetic Kidney Disease

Objective

To explore the association of the trajectory of serum Cystatin C (Cysc) with diabetic kidney disease (DKD), a retrospective cohort study of Chinese subjects was carried out.

Method

A review of 2,928 diabetes mellitus (DM) patients admitted to the clinic and ward of the Endocrinology Department, Shengjing Hospital of China Medical University from January 1, 2014 to December 31, 2014 was performed. Subsequent visits to the hospital were followed until December 31, 2020. The primary endpoint was the incidence of DKD as diagnosed by urinary albumin/creatinine ratio ≥30 mg/g and/or estimated glomerular filtration rate <60 ml/min per 1.73 m2. Healthy control subjects were identified from a health checkup database in Shengjing Hospital from 2016 to 2019. The latent class growth mixed modeling (LCGMM) method was used to analyze latent classes of serum Cysc in healthy and DM subjects. Finally, the hazard ratios (HRs) of latent classes of Cysc in DM subjects were analyzed by Cox regression analysis.

Results

A total of 805 type 2 diabetes mellitus (T2DM) and 349 healthy subjects were included in the trial. The HRs of quartiles of baseline Cysc in T2DM subjects were 7.15 [95% confidence interval (CI), 2.79 to 25.57], 2.30 (95% CI, 1.25 to 4.24), and 2.05 (95% CI, 1.14 to 3.70), respectively, for quartile 4 (Q4), Q3, and Q2 when compared with Q1. Through LCGMM, a 1-class linear model was selected for the Cysc latent class in healthy subjects. In contrast, a 3-class linear model was selected for that in DM subjects. The slopes of the three latent classes in T2DM subjects were larger than the slope in healthy subjects. The HRs of incident DKD were 3.43 (95% CI, 1.93 to 6.11) for the high-increasing class and 1.80 (95% CI, 1.17 to 2.77) for the middle-increasing class after adjusting for confounding variables.

Conclusions

Patients with T2DM had a higher velocity of increase in Cysc than healthy subjects. Patients with high baseline Cysc values and high latent increasing velocity of Cysc had a higher risk of developing DKD in later life. More attention should be paid to patients with these high-risk factors.

Hyperhomocysteinemia exacerbates ischemia-reperfusion injury-induced acute kidney injury by mediating oxidative stress, DNA damage, JNK pathway, and apoptosis

Background

Hyperhomocysteinemia (HHcy) plays an important role in the progression of many kidney diseases; however, the relationship between HHcy and ischemia-reperfusion injury (IRI)-induced acute kidney injury (IRI-induced AKI) is far from clear. In this study, we try to investigate the effect and possible mechanisms of HHcy on IRI-induced AKI.

Methods

Twenty C57/BL6 mice were reared with a regular diet or high methionine diet for 2 weeks (to generate HHcy mice); after that, mice were subgrouped to receive sham operation or ischemia-reperfusion surgery. Twenty four hour after reperfusion, serum creatinine, blood urea nitrogen, and Malondialdehyde (MDA) were measured. H&E staining for tubular injury, western blot for γH2AX, JNK, p-JNK, and cleaved caspase 3, and TUNEL assay for tubular cell apoptosis were also performed.

Results

Our results showed that HHcy did not influence the renal function and histological structure, as well as the levels of MDA, γH2AX, JNK, p-JNK, and tubular cell apoptosis in control mice. However, in IRI-induced AKI mice, HHcy caused severer renal dysfunction and tubular injury, higher levels of oxidative stress, DNA damage, JNK pathway activation, and tubular cell apoptosis.

Conclusion

Our results demonstrated that HHcy could exacerbate IRI-induced AKI, which may be achieved through promoting oxidative stress, DNA damage, JNK pathway activation, and consequent apoptosis.

Clinical significance of serum homocysteine as a biomarker for early diagnosis of diabetic nephropathy in type 2 diabetes mellitus patients

Objective

The aim of this study was to investigate the clinical significance of serum homocysteine (Hcy) as a biomarker for early diagnosis of diabetic nephropathy (DN) in type 2 diabetes mellitus (T2DM) patients.

Methods

Fifty-five T2DM patients with DN and 51 T2DM patients without DN were prospectively recruited from January 2016 to May 2020 in our hospital. The serum Hcy was tested by electrochemiluminescence assay in DN and T2DM groups and compared. The diagnostic efficacy of serum Hcy as a biomarker for early diagnosis of DN was evaluated by calculating the diagnostic sensitivity, specificity and area under the ROC curve (AUC).

Results

The serum levels of Hcy were 15.49 ± 5.40 and 9.23 ± 3.15 μmol/L for DN and T2DM patients, respectively, with statistical difference (t = 7.21, P < 0.001). In the DN group, the serum Hcy levels for patients with hyperfiltration, intermittent proteinuria, microalbuminuria, macroalbuminuria and uremic were 10.99 ± 2.57, 13.90 ± 2.86, 15.38 ± 4.77, 18.98 ± 4.36 and 23.31 ± 5.22 μmol/L, respectively, which indicated that serum Hcy levels in DN were higher than those of T2DM patients and correlated with patient’s renal damage. Using the serum Hcy level as the reference, the diagnostic sensitivity, specificity and AUC were 84.31 (71.41–92.98)%, 74.55 (61.00–85.33)% and 0.85 (0.78–0.92)%, respectively, with the cutoff value of 12.08 between DN and T2DM. The serum Hcy also had relatively good differential diagnostic efficacy between different DN stages with high sensitivity, specificity and AUC.

Conclusion

Serum Hcy was obviously elevated in DN compared to T2MD and correlated with the renal damage severity, which can be applied as a potential serological marker for early diagnosis of DN.