Cystatin C and Cystatin Glomerular Filtration Rate as Markers of Early Renal Disease in Asian Indian Subjects With Glucose Intolerance (CURES-32)

Role of cystatin C in the detection of sight-threatening diabetic retinopathy in Asian Indians with type 2 diabetes

AIM

To study the association between cystatin C and sight-threatening diabetic retinopathy (STDR) in Asian Indians with type 2 diabetes (T2DM).

METHODS

In a cross-sectional study carried out at two tertiary centres in India in 2022, individuals with T2DM underwent clinical and ophthalmic assessments and estimation of serum cystatin C. Grading of DR was done by retina specialists. STDR was defined by the presence of severe non-proliferative DR (NPDR), proliferative DR (PDR) and/or diabetic macular edema. Receiver operating characteristic (ROC) curves were used to identify cystatin C cut-off value for detecting STDR.

RESULTS

Among 420 individuals with T2DM (mean age 56 ± 9 years; mean duration of diabetes 14.5 ± 7.9 years), 121 (24.1 %) had No-DR, 119 (28.3 %) had No-STDR and 200 (49.6 %) had STDR. Mean cystatin C level was significantly higher in individuals with STDR compared to those with no-STDR and No-DR (1.34 vs 1.06 vs 0.93 mg/L, p < 0.001). Cystatin C cut-off value ≥1.11 mg/L had a C statistic of 0.944 (95 % CI: 0.909-0.968, p < 0.001), 96.8 % sensitivity and 78.2 % specificity for detection of STDR.

CONCLUSION

Elevated serum cystatin C was strongly associated with STDR and could possibly be used as a biomarker for screening for sight-threatening diabetic retinopathy.

Blood and Urinary Biomarkers of Antipsychotic-Induced Metabolic Syndrome

Metabolic syndrome (MetS) is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Antipsychotic (AP)-induced MetS (AIMetS) is the most common adverse drug reaction (ADR) of psychiatric pharmacotherapy. Herein, we review the results of studies of blood (serum and plasma) and urinary biomarkers as predictors of AIMetS in patients with schizophrenia (Sch). We reviewed 1440 studies examining 38 blood and 19 urinary metabolic biomarkers, including urinary indicators involved in the development of AIMetS. Among the results, only positive associations were revealed. However, at present, it should be recognized that there is no consensus on the role of any particular urinary biomarker of AIMetS. Evaluation of urinary biomarkers of the development of MetS and AIMetS, as one of the most common concomitant pathological conditions in the treatment of patients with psychiatric disorders, may provide a key to the development of strategies for personalized prevention and treatment of the condition, which is considered a complication of AP therapy for Sch in clinical practice.

Huoxue Qianyang Qutan Recipe Protects against Early Renal Damage Induced by Obesity-Related Hypertension via the SIRT1/NF-κB/IL-6 Pathway: Integrating Network Pharmacology and Experimental Validation-Based Strategy

Obesity is recognized as not only a major contributing factor to cardiovascular diseases but also an independent risk factor for end-stage renal disease. Previous studies have found that Huoxue Qianyang Qutan Recipe (HQQR) could reduce urinary microalbumin in patients with obesity-related hypertension (OBH). However, the renal protective activity of HQQR in OBH and its molecular targets involved remains ambiguous. In this work, we investigate the mechanism of HQQR against OBH-induced early renal damage using integrating network pharmacology and experimental validation-based strategy. First, via network pharmacology, IL-6 is identified as one of the key targets of HQQR against early renal damage in hypertension, and inhibition of inflammation is a crucial process. Second, in in vivo experiments, HQQR can lower blood pressure, lose weight, and restore metabolic abnormalities in OBH rats, which could be associated with the effects on protecting early renal damage. Finally, in the mechanism, HQQR increases SIRT1 mRNA and protein expression consistent with reduction of NF-κB acetylation and suppressed the p65-mediated inflammatory signaling pathway. As a result, HQQR robustly inhibits OBH-induced renal inflammation by reducing IL-6 mRNA and protein levels in the renal tissue and the release of IL-6 in serum of OBH rats. This study aims to provide a multimethod (network pharmacology-animal experiment) and multilevel (component-target-pathway) strategy for the prevention and treatment of OBH-induced target organ damage by traditional Chinese medicine.

A literature survey on the biomarkers of cardiovascular disease

The following core competencies are addressed in this article:

Medical knowledge, Patient care, Systems-based practice.

To Compare the Level of Cystatin C in Type 2 Diabetes Mellitus with Obesity

BACKGROUND

Cystatin C is a non-glycosylated basic protein that is produced and secreted at a constant rate by all nucleated cells. Cystatin C is a more reliable marker than the serum creatinine because it is less affected by external factors such as gender, race and muscle mass. However, the comparison of serum cystatin C level in type 2 diabetes mellitus is not well known in people with obesity.

OBJECTIVES

To estimate the level of cystatin C in type 2 diabetes and that can be explained by the change in obesity. Thus, this current study aimed to determine and compare the level of cystatin C in type 2 DM with obesity and also correlate the cystatin C level with the quality of life in type 2 DM and obesity.

MATERIAL AND METHODS

We have taken three groups: Group A containing type 2 DM, Group B containing obesity, and Group C containing type 2 DM with obesity. In all, 25 patients in each group were selected and analyzed for cystatin C.

RESULTS

Cystatin C level was very high in type 2 DM with obesity group. The P value was 0.008 in type 2 DM with the obesity group and it has shown a highly significant correlation with BMI. In our study, we have also seen the positive correlation of cystatin C with BMI in Group B plain obese and Group C diabetes obese than Group A diabetes non-obese. We have seen in our study and found a poor correlation between HbA1c, RBS and cystatin C.

CONCLUSION

The level of cystatin C is much higher in type 2 DM with obese patient as compared with type 2 DM and obese patients.

Association of circulating cystatin C levels with type 2 diabetes mellitus: a systematic review and meta-analysis

INTRODUCTION

This study aimed to systemically summarize the present literature about circulating cystatin C (Cys C) levels in type 2 diabetes mellitus (T2DM) and provide a more precise evaluation of Cys C levels in T2DM.

MATERIAL AND METHODS

Relevant studies about Cys C concentrations in T2DM were searched in PubMed, EMBASE and the Cochrane Library database (up to Oct 31 2018). We computed the pooled standard mean difference (SMD) with its 95% confidence interval (CI) of Cys C levels through a random-effect model. The Q test and the I² statistic were used to assess and quantify between-study heterogeneity; publication bias was evaluated through a funnel plot and Egger's linear regression test.

RESULTS

After the literature search and screening process, 14 studies with 723 T2DM patients and 473 healthy controls were finally included in the meta-analysis. The results showed that T2DM patients had significantly higher Cys C levels compared to healthy controls (SMD = 1.39, 95% CI: 0.92-1.86, p < 0.001). Publication bias was not detected based on the symmetrical shape of the funnel plot and the results of Egger's test (p = 0.452). Subgroup analyses suggested that variables of human race, age, gender, study sample size and disease duration have a relationship with Cys C level in T2DM patients.

CONCLUSIONS

Overall, our study suggests that patients with T2DM have an elevated circulating Cys C level compared to healthy controls, and it is associated with race, age, gender, study sample size and disease duration. Further investigations are still needed to explore the causal relationship of aberrant Cys C concentrations in T2DM.

Association of retinol binding protein-4, cystatin C, homocysteine and high-sensitivity C-reactive protein levels in patients with newly diagnosed type 2 diabetes mellitus

INTRODUCTION

To investigate the serum retinol binding protein (RBP)-4, cystatin C (Cys C), homocysteine (HCY) and high-sensitivity C-reactive protein (hs-CRP) levels in newly diagnosed type 2 diabetes mellitus (NT2DM) patients, prediabetes mellitus (PDM) subjects and normal controls, as well as their correlation with clinical and laboratory indexes, such as blood pressure and lipoprotein.

MATERIAL AND METHODS

A total of 242 subjects, including 141 NT2DM patients, 48 PDM subjects and 53 healthy controls, were recruited in the present study. Serum RBP-4, Cys C and hs-CRP concentrations were measured by enzyme-linked immunosorbent assay (ELISA). HCY concentration was determined by the chemical luminescence method.

RESULTS

There were significant differences in Cys C and hs-CRP among NT2DM patients, PDM subjects and normal controls. In comparison to controls, there were significantly elevated Cys C and hs-CRP levels in PDM (both p < 0.001), and a significantly increased Cys C level in NT2DM (p < 0.001); however, there were no significant differences in Cys C and hs-CRP levels between NT2DM and PDM, and no significant differences of hs-CRP levels between NT2DM and normal controls. No significant differences of RBP-4 and HCY levels among NT2DM, PDM and normal control groups were observed.

CONCLUSIONS

Aberrant Cys C expression and its clinical associations in NT2DM suggest their important role in this disease.

Elevated Squamous Cell Carcinoma Antigen, Cytokeratin 19 Fragment, and Carcinoembryonic Antigen Levels in Diabetic Nephropathy

OBJECTIVE

We aimed to explore whether squamous cell carcinoma antigen (SCC), cytokeratin 19 fragment (Cyfra21-1), neuron-specific enolase (NSE), and carcinoembryonic antigen (CEA) are elevated in diabetic nephropathy (DN) and the association between urinary albumin-to-creatinine ratio (UACR) and tumor markers in diabetic patients.

METHODS

Nondialysis patients with diabetes (n = 261) and 90 healthy controls were enrolled. DN was defined as an UACR ≥ 30 mg/g in the absence of a urinary tract infection or other renal abnormalities.

RESULTS

Patients with DN had significantly higher serum SCC, Cyfra21-1, and CEA levels than those with normoalbuminuria and healthy controls. The rates of positive SCC, Cyfra21-1, and CEA significantly increased with increasing urinary albumin excretion (all P for trend < 0.001). In contrast, NSE was not affected by DN. SCC, Cyfra21-1, and CEA were significantly and positively correlated with UACR. In logistic regression, after multivariable adjustment, increased UACR was associated with increased odds ratio of elevated tumor marker levels (all P for trend < 0.05).

CONCLUSIONS

Serum levels of SCC, Cyfra21-1, and CEA are markedly increased with increasing urinary albumin excretion, which affects the specificity for diagnosis for lung cancer. Appropriate interpretation of tumor markers in diabetic patients is mandatory to avoid unnecessary and even hazardous biopsies.

Biomarkers of Metabolic Syndrome: Biochemical Background and Clinical Significance

Biomarkers of the metabolic syndrome are divided into four subgroups. Although dividing them in groups has some limitations, it can be used to draw some conclusions. In a first part, the dyslipidemias and markers of oxidative stress are discussed, while inflammatory markers and cardiometabolic biomarkers are reviewed in a second part. For most of them, the biochemical background and clinical significance are discussed, although here also a well-cut separation cannot always be made. Altered levels cannot always be claimed as the cause, risk, or consequence of the syndrome. Several factors are interrelated to each other and act in a concerted, antagonistic, synergistic, or modulating way. Most important conclusions are summarized at the end of every reviewed subgroup. Genetic biomarkers or influences of various food components on concentration levels are not included in this review article.

Soluble CD36 in plasma and urine: a plausible prognostic marker for diabetic nephropathy

AIMS

This study was designed to analyze the level of soluble CD36 (sCD36) in both plasma and urine of type 2 diabetic patients with and without microalbuminuria/macroalbuminuria.

METHODS

Study subjects (n=20 each) comprised of those with normal glucose tolerance, type 2 diabetes (T2DM) with normoalbuminiria, T2DM with microalbuminuria and T2DM with macroalbuminuria. The biochemical parameters were analyzed using auto-analyzer, and the level of sCD36 was estimated using an in-house Sandwich ELISA.

RESULTS

The presence of sCD36 has been identified for the first time in the urine sample. Significant increase in the level of sCD36 was observed in both plasma and urine of diabetic patients with microalbuminuria (P<0.01) and macroalbuminuria (P<0.001). Positive correlation of sCD36 with the kidney markers such as urea, creatinine and eGFR confirmed the association of sCD36 with kidney damage in diabetic patients. Microalbuminuria, which is clinically used as a biomarker for nephropathy showed a strong positive correlation with urine sCD36 (r=0.642; P<0.001) and plasma sCD36 (r=0.498; P<0.001) in Pearson correlation analysis, which was further substantiated in stepwise multiple regression analysis.

CONCLUSIONS

Our study implies a plausible prognostic/adjuvant biomarker role of soluble CD36 for diabetic nephropathy.

Serum adiponectin helps to differentiate type 1 and type 2 diabetes among young Asian Indians

OBJECTIVE

This study assessed whether serum adiponectin could be used as a biochemical marker to differentiate type 1 diabetes mellitus (T1DM) from type 2 diabetes mellitus (T2DM) among young Asian Indians.

RESEARCH DESIGN AND METHODS

We recruited age- and sex-matched individuals with physician-diagnosed T1DM (n=70) and T2DM (n=72). All were 12-27 years of age with a duration of diabetes of >2 years, at a large tertiary-care diabetes center in Chennai, southern India. Age- and sex-matched individuals with normal glucose tolerance (NGT) (n=68) were selected from an ongoing population study. NGT was defined using World Health Organization criteria. Serum total adiponectin was measured by enzyme-linked immunosorbent assay. Receiver operating characteristic (ROC) curves were used to identify adiponectin cut points for discriminating T1DM from T2DM.

RESULTS

Adiponectin levels were higher in T1DM and lower in T2DM compared with the NGT group (9.89, 3.88, and 6.84 μg/mL, respectively; P<0.001). In standardized polytomous regression models, adiponectin was associated with T1DM (odds ratio [OR]=1.131 per SD; 95% confidence interval [CI], 1.025-1.249) and T2DM (OR=0.628 per SD; 95% CI, 0.504-0.721) controlled for age, gender, waist circumference, body mass index, hypertension, glycated hemoglobin, total cholesterol, serum triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, family history of T2DM, and estimated glomerular filtration rate. Using ROC analysis, an adiponectin cut point of 5.1 μg/mL had a C statistic of 0.886 (95% CI, 0.836-0.953), sensitivity of 80.6%, and specificity of 80.6% to differentiate T1DM from T2DM. Using the 5.1 μg/mL cut point, 80.6% of T1DM and 81.8% of T2DM would be correctly classified.

CONCLUSIONS

Serum adiponectin is a useful biochemical marker for differentiating T1DM and T2DM among young Asian Indians.

Urinary tubular biomarkers in short-term type 2 diabetes mellitus patients: a cross-sectional study

The purpose of this study was to investigate the prevalence of tubular damage in short-term (less than five years) type 2 diabetes mellitus (T2DM) patients and to explore the correlation between tubular markers and their relationship with renal indices at different stages of diabetic nephropathy. A group of 101 short-term T2DM patients and 28 control subjects were recruited. Tubular markers, such as neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl-β-D: -glucosaminidase (NAG), and kidney injury molecule 1 (KIM-1), as well as urinary albumin excretion were measured in voided urine. Glomerular filtration rate (GFR) was estimated via Macisaac's formula. The patients were further categorized into three groups, namely, the normoalbuminuria, microalbuminuria, and macroalbuminuria groups, according to their urine albumin/creatinine ratio (UACR). Urinary tubular markers were compared and their correlations with renal indices [UACR and estimated GFR (eGFR)] were analyzed among the different diabetic groups. Compared with the control group, Urinary NGAL [median (IQR)][83.6(41.4-138.7) μg/gcr vs. 32.9(26.1-64.5) μg/gcr], NAG [13.5(8.7-17.9) U/gcr vs. 7.6(6.5-13.0) U/gcr] and KIM-1 [120.0(98.4-139.9) ng/gcr vs. 103.1(86.8-106.2) ng/gcr] in the T2DM were all markedly increased. For all patients, urinary NGAL had stronger positive correlations with UACR than NAG (R = 0.556 vs. 0.305, both P < 0.05). In addition, only urinary NGAL showed a negative correlation with eGFR (R = -0.215, P < 0.05). Urinary KIM-1, however, showed no significant difference among the three T2DM groups and did not correlate with either UACR or eGFR. As UACR increased from the normoalbuminuria to the last macroalbuminuria group, all of the markers increased. However, only the concentrations of NGAL were statistically different among the three diabetic groups. The correlation between the tubular markers and their relationships with the renal indices differed markedly among the three T2DM groups. In conclusion, these results suggest that tubular damage is common in short-term T2DM patients. Urinary NGAL may be a promising early marker for monitoring renal impairment in short-term T2DM patients.

Association of cystatin-C with metabolic syndrome in normal glucose-tolerant subjects (CURES-97)

BACKGROUND

This study looked at the association of cystatin-C (cys-C) with severity of metabolic syndrome in Asian Indians.

METHODS

Five sets of normal glucose tolerance subjects were recruited from the Chennai Urban Rural Epidemiology Study (CURES), a population-based study in southern India: 43 subjects with no metabolic risk factors, 44 subjects with one metabolic risk factor, 37 subjects with two risk factors, 40 subjects with three risk factors, and 40 subjects with four or five metabolic risk factors. Metabolic syndrome was defined using National Cholesterol Education Program criteria for adults modified for waist measured using the World Health Organization Asia Pacific guidelines. Serum cys-C was estimated by a high-sensitivity particle-enhancing nephelometry assay.

RESULTS

Subjects with four or five metabolic abnormalities had the highest cys-C levels, and with decreasing number of metabolic abnormalities, the cys-C levels decreased linearly (P for trend < 0.001). Regression analysis showed a linear increase in cys-C levels with increasing number of metabolic abnormalities.

CONCLUSION

Cys-C levels are highly correlated with the number of metabolic abnormalities in Asian Indians.

Cystatin C and blood pressure: results of 24 h ambulatory blood pressure monitoring

BACKGROUND

The relationship between kidney function and blood pressure (BP) components has been studied in chronic kidney disease patients. Whether cystatin C, a marker of kidney function, is associated in the normal range with systolic BP (SBP), diastolic BP (DBP), and pulse pressure (PP) obtained using ambulatory blood pressure monitoring has not been previously studied.

METHODS

The sample subjects were 53 males and 34 females, mean age was 59.3+/-13.5 years. 76% were receiving antihypertensive drug treatment. Kidney function was evaluated by measuring serum cystatin C. Microalbuminuria was measured in a 24h urine collection. Glomerular filtration rate (GFR) was estimated using the abbreviated Modification of Diet in Renal Disease equations. The ambulatory BP was measured non-invasively for 24h by the Spacelab devices programmed to measure BP every 15 min during daytime and every 20 min during nighttime.

RESULTS

The highest quartile of cystatin C distribution showed an older age and worsel parameters of renal function (cystatin C, serum creatinine and GFR) than the other groups. No differences for gender or diabetes were found. 24h SBP and PP were higher in the fourth quartile compared to the fist one (p<0.01). 24h DBP was lower for the patients in the fourth quartile of cystatin C compared which any one of the other groups (p<0.001). The relationship between cystatin C, as well as GFR, with SBP and PP was statistically significant as renal function comes down. Contrariwise, as cystatin C increases DBP declines; but the correlation with GFR measured through MDRD 4 is not significant. In the same way, no correlation was found for GFR and microalbuminuria, but there was a statistically significant positive relationship between cystatin C and microalbuminuria severity (p<0.01). Multivariate regression analysis confirms these findings.

CONCLUSIONS

Both SBP and pulse pressure were significantly associated with kidney function. DBP was negatively correlated with cystatin C concentrations but not with GFR. Cystatin C shows a positive relationship with microalbuminura severity. Cystatin C might have cardiovascular effects beyond its use as a marker of the renal function.