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

Serum cystatin C and mild cognitive impairment: The mediating role of glucose homeostasis

Background

This study explored the mediating role of glucose homeostasis indicators in the relationship between serum cystatin C and mild cognitive impairment (MCI).

Methods

The present study used a cross-sectional design and included 514 participants aged ≥50 years in Beijing, China. The Mini-Mental State Examination was used to assess cognitive function. Serum cystatin C and a comprehensive set of glucose homeostasis indicators were detected, including fasting blood glucose (FBG), glycosylated albumin percentage (GAP), glycated hemoglobin (HbAlc), insulin, and homeostatic model assessment of insulin resistance (HOMA-IR), and beta cell function (HOMA-β). Generalized linear models were used to investigate the associations among cystatin C, glucose homeostasis indicators, and cognitive function. Mediation analysis was conducted to explore potential mediator variables.

Results

In this study of 514 participants, 76 (14.8%) had MCI. Those with cystatin C levels ≥1.09 mg/L had a 1.98-fold higher risk of MCI than those with levels <1.09 mg/L (95% CI, 1.05–3.69). FBG, GAP, and HbA1c increased the risk of MCI, while HOMA-β decreased the risk. Notably, the associations between MCI risk and cystatin C or glucose homeostasis were only founded in diabetes patients. Serum cystatin C was found to be positively associated with HOMA-β (beta (95% CI): 0.20 [0.06, 0.34]), HOMA-IR (0.23 [0.09, 0.36]), and insulin (0.22 [0.09, 0.34]) levels. Moreover, HOMA-β was identified as playing a negative mediating role (proportion mediated: −16%) in the relationship between cystatin C and MCI.

Conclusion

Elevated levels of cystatin C are associated with an increased risk of MCI. The glucose homeostasis indicator, HOMA-β, plays a negative mediating role in the relationship between cystatin C and MCI risk.

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.

Association between circulating cystatin C and hyperuricemia: a cross-sectional study

INTRODUCTION/OBJECTIVES

Circulating cystatin C has reportedly been related to cardiovascular disease, diabetes, and metabolic syndrome, apart from its traditional role in estimating the glomerular filtration rate. However, whether circulating cystatin C is related to hyperuricemia remains unclear.

METHOD

We included 2406 men and 1273 women who attended their annual health checkups in this study. Anthropometric and biochemical parameters were measured. Hyperuricemia was diagnosed as fasting serum uric acid > 420 µmol/L in men and women.

RESULTS

A total of 695 (18.9%) participants were diagnosed with hyperuricemia. Hyperuricemic patients had significantly higher serum cystatin C levels than healthy controls (0.91 (0.83-1.02) versus 0.82 (0.72-0.92) mg/L, P < 0.001). Serum cystatin C levels were positively related to the prevalence of hyperuricemia, which was 5.18%, 14.76%, 22.66%, and 31.24% in participants with serum cystatin C levels in the first, second, third, and fourth quartiles, respectively (P < 0.001 for trend). In stepwise multivariate logistic regression analysis, participants with serum cystatin C in the fourth quartile had a more than twofold increased risk of hyperuricemia (OR 2.262, 95% CI 1.495-3.422; P < 0.001) compared with those with serum cystatin C in the first quartile. In subgroup analyses, the fourth quartile of cystatin C was related to increased risks of hyperuricemia in both non-obese and obese participants (OR 4.405, 95% CI 1.472-13.184, P = 0.008; OR 1.891, 95% CI 1.228-2.911, P = 0.004, respectively), in non-metabolic syndrome participants (OR 3.043, 95% CI 1.692-5.473; P < 0.001) but not in metabolic syndrome participants (OR 1.689, 95% CI 0.937-3.045; P = 0.081), and in non-non-alcoholic fatty liver disease (non-NAFLD) (OR 2.128, 95% CI 1.424-3.180; P < 0.001, respectively) and young and middle-aged participants (OR 2.235, 95% CI 1.492-3.348, P < 0.001) but not in NAFLD and elderly participants.

CONCLUSIONS

This study revealed a positive association of circulating cystatin C with hyperuricemia. Key Points • Serum cystatin C is associated with an increased risk of hyperuricemia. • Serum cystatin C is a useful biomarker in distinguishing patients at high risk of having hyperuricemia.

Independent associations of urinary albumin-to-creatinine ratio and serum cystatin C with carotid intima-media thickness in community-living Taiwanese adults

Background

Renal function is a key factor of cardiovascular disease. Carotid intima-media thickness (IMT) has been widely used as a marker of early subclinical atherosclerosis. The determinants of cystatin C, a novel marker of renal function, have not been extensively studied in the Asian population. This study aimed to assess the determinants of cystatin C and explore whether carotid thickening was associated with urinary albumin-creatinine ratio and cystatin C in community-living Taiwanese adults.

Methods

A cross-sectional study was conducted on participants from Taichung City, Taiwan. All the participants underwent carotid ultrasonography. Carotid IMT-mean and IMT-maximum were derived. Kidney biomarkers were measured on the basis of urinary albumin-to-creatinine ratio (ACR) and cystatin C. Multiple linear regression analysis was used.

Results

A total of 1032 individuals were recruited, and 469 (45.44%) of them were men. An increased cystatin C level was significantly associated with older age, male gender, lack of physical activity, low HDL cholesterol, abdominal obesity, high hs-CRP, and high ACR. The multivariate-adjusted mean carotid IMT-mean and IMT-maximum values significantly increased by 80.49 and 195.23 μm for every one unit of increase in cystatin C level and by 0.07 and 0.14 μm for every one unit of increase in ACR, respectively (all p < 0.001 except ACR on IMT-maximum with p < 0.01). Lack of physical activity, low HDL, abdominal obesity, high hs-CRP, and high ACR were the determinants of cystatin C.

Conclusion

Cystatin C and ACR were strongly and linearly associated with carotid thickening, a marker of subclinical atherosclerosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-020-02123-x.

Discrepant glomerular filtration rate trends from creatinine and cystatin C in patients with chronic kidney disease: results from the KNOW-CKD cohort

Background

Serum creatinine (Cr) and cystatin C (CysC) can both be used to estimate glomerular filtration rate (eGFR_Cr and eGFR_CysC). However, certain conditions may cause discrepancies between eGFR trends from Cr and CysC, and these remain undetermined in patients with chronic kidney disease (CKD).

Methods

A total of 1069 patients from the Korean CKD cohort (KNOW-CKD), which enrolls pre-dialytic CKD patients, whose Cr and CysC had been followed for more than 4 years were included in the sample. We performed trajectory analysis using latent class mixed modeling and identified members of the discrepancy group when patient trends between eGFR_Cr and eGFR_CysC differed. Multivariate logistic analyses with Firth’s penalized likelihood regression models were performed to identify conditions related to the discrepancy.

Results

Trajectory patterns of eGFR_Cr were classified into three groups: two groups with stable eGFR_Cr (stable with high eGFR_Cr and stable with low eGFR_Cr) and one group with decreasing eGFR_Cr. Trajectory analysis of eGFR_CysC also showed similar patterns, comprising two groups with stable eGFR_CysC and one group with decreasing eGFR_CysC. Patients in the discrepancy group (decreasing eGFR_Cr but stable & low eGFR_CysC; n = 55) were younger and had greater proteinuria values than the agreement group (stable & low eGFR_Cr and eGFR_CysC; n = 706), differences that remained consistent irrespective of the measurement period (4 or 5 years).

Conclusions

In the present study, we identify conditions related to discrepant trends of eGFR_Cr and eGFR_CysC. Clinicians should remain aware of such potential discrepancies when tracing both Cr and CysC.

Clinical utility of serum cystatin C for prediction of multi-vessel disease by coronary angiography in type 2 diabetes mellitus patients with normal renal function

BACKGROUND

The aim of this study was to evaluate whether serum cystatin C could serve as a predictor of multivessel coronary artery disease identified by coronary angiography in type 2 diabetes patients with normal renal function and to suggest the cutoff point of serum cystatin C for predicting multivessel disease.

METHODS

Serum cystatin C concentrations were measured by using particle-enhanced immunonephelometric assays before coronary angiography in 135 consecutive type 2 diabetes patients and 179 nondiabetic patients with normal renal function. Routine anthropometric and serologic data were collected. The severity of multivessel disease was assessed with the Gensini score after coronary angiography. The associations of serum cystatin C with the Gensini score were investigated, and the independent risk factors associated with multivessel disease were assessed.

RESULTS

Serum cystatin C and the Gensini score were significantly elevated in diabetes patients. Cystatin C had a positive correlation with Gensini score. A multiple logistic regression analysis demonstrated that cystatin C was independently associated with the presence of multivessel disease (the OR score is 2.21, P = 0.003). Based on the ROC curve, a cystatin C level of 0.865 mg/L showed 67.7% sensitivity and 76.3% specificity with an AUC of 0.748 in diabetes patients for detecting multivessel disease.

CONCLUSION

Serum cystatin C is significantly correlated with the presence of multivessel disease, suggesting that cystatin C might be utilized as a screening tool for predicting multivessel disease in type 2 diabetes mellitus patients with normal renal function.

Association of Cystatin C with Metabolic Syndrome and Its Prognostic Performance in Non-ST-Segment Elevation Acute Coronary Syndrome with Preserved Renal Function

OBJECTIVE

The underlying mechanisms by which cystatin C affects cardiovascular disease (CVD) are not very clear. Metabolic syndrome (MetS) is a cluster of risk factors that increase the risk of CVD. Here, we aimed to investigate the association of cystatin C with metabolic syndrome and cardiovascular outcomes in non-ST-segment elevation acute coronary syndrome (NSTE-ACS) with preserved renal function.

METHODS

In total, 422 NSTE-ACS patients with preserved renal function were enrolled to examine the association of cystatin C with MetS. MetS was defined based on the NCEP-ATP-III guidelines. Major adverse cardiovascular events (MACEs) were also evaluated, which included cardiac death, nonfatal myocardial infarction (MI), target vessel revascularization (TVR), heart failure, and nonfatal stroke. All patients underwent a 12-month follow-up for MACEs after admission.

RESULTS

Cystatin C was significantly correlated with metabolic risk factors and inflammation markers. The prevalence of MetS and MACEs correlated with cystatin C levels. Cystatin C showed a strong diagnostic performance for cardiovascular risk factors and outcomes in ROC analysis. After adjustment for multiple risk factors, cystatin C level was independently associated with MetS (OR 2.299, 95% CI 1.251-4.225, and P = 0.007). During a 12-month follow-up, the patients with high cystatin C level and MetS had higher incidence of MACEs (Log-rank = 24.586, P < 0.001) and cardiac death (Log-rank = 9.890, P = 0.020) compared to the others. Multivariate Cox analysis indicated that cystatin C level was an independent predictor of MACEs (HR 2.609, 95% CI 1.295-5.257, and P = 0.007).

CONCLUSION

Cystatin C may be an independent predictor of metabolic syndrome and therefore valuable for management of NSTE-ACS patients. Further multicenter, large-scale studies are required to assess the implication of these results.

Retinol-binding protein 4 better correlates with metabolic syndrome than cystatin C

Background

Retinol-binding protein 4 (RBP4) and cystatin C are regarded as novel metabolic risk markers. Therefore, we aimed to examine which one of these biomarkers better correlates with metabolic syndrome (MetS) in a cohort of postmenopausal women.

Methods

A total of 129 postmenopausal women (among which 62 women had MetS) were recruited in this cross-sectional study. MetS was diagnosed according to the International Diabetes Federation criteria.

Results

Cystatin C and RBP4 levels were significantly higher in women with MetS, compared to those without MetS (p=0.011 vs. p<0.001, respectively). A significant difference in the proportion of women with and without MetS across cystatin C and RBP4 quartiles was observed (χ2=5.1, p=0.025, and χ2=11.1, p=0.001, respectively). Logistic regression analysis revealed a borderline significant relationship between cystatin C and MetS (p=0.066), but this significance disappeared after adjustment for age, inflammation level and duration of menopause (p=0.221). On the contrary, a significant relationship between RBP4 and MetS was observed not only without adjustment (p=0.009), but also even after adjustment for age, inflammation level and duration of menopause (p=0.006).

Conclusions

RBP4 better correlates with MetS than cystatin C in postmenopausal women.

Cystatin C in adipose tissue and stimulation of its production by growth hormone and triiodothyronine in 3T3-L1 cells

Cystatin C (CysC) is a marker for estimation of glomerular filtration rate (GFR). CysC levels may depend not only on clearance/GFR but possibly also on changes in production. Our studies on tissue distribution of CysC protein in mice showed that adipose tissue expresses significant amounts of CysC, suggesting that adipocytes could contribute to circulating CysC levels in vivo. As growth hormone (GH) and triiodothyronine (T₃) increase both GFR and CysC (increased in acromegaly and hyperthyroidism) in vivo, we studied whether they could increase CysC production in 3T3-L1 adipocytes in vitro. CysC accumulated in culture media of 3T3-L1 adipocytes in a time-dependent fashion. GH and T₃ both (10 nmol/l) increased accumulation of CysC, to 373 ± 14 and 422 ± 20, respectively, vs 298 ± 10 ng per well over 4 days in controls. Thus, GH and T₃ enhance the production of CysC by adipocytes in vitro.

Cystatin-C and epicardial adipose tissue as noninvasive predictors of cardiovascular risk in acromegaly

BACKGROUND

Acromegaly (ACRO) is associated with elevated cardiovascular risk, although the prevalence of coronary artery disease (CAD) is unclear. Increased epicardial adipose tissue (EAT) and elevated cystatin-C (Cys-C) levels are cardiovascular risk factors, also related to the progression of CAD in several populations.

AIMS

To measure the severity and extent of CAD in patients with ACRO and to determine whether either EAT or Cys-C reflect higher cardiovascular risk in patients with ACRO than in healthy controls.

SUBJECTS AND METHODS

Case-control study, of 35 patients with ACRO (19 males, 17 with active disease) and 35 age-, gender- and body mass index (BMI)-matched healthy controls; mean age was 48·1 ± 8·1 years and mean BMI was 27·6 ± 4·8 kg/m² . Cys-C was measured by an immunoturbidimetric assay. The 10-year risk of developing a coronary event was calculated using the Framingham Risk Score (FRS). EAT index (volume indexed to body surface area), and severity and extent of CAD were measured using a 256-slice multidetector computed tomography scanner (iCT-256 Philips Healthcare, Amsterdam).

RESULTS

Coronary artery disease lesions, EAT index and severity/extent of CAD were similar between patients with ACRO and controls. Forty-four per cent of patients with ACRO had mild coronary lesions associated with greater EAT index (ß = 0·022, P = 0·036). Cys-C levels correlated with both EAT index (ρ = 0·386, P = 0·031) and FRS (ρ = 0·477, P = 0·004) in patients with ACRO only, despite similar prevalence of traditional cardiovascular risk factors. In a multiple linear regression model, both Cys-C levels (ß = 0·369, P = 0·007) and EAT index (ß = 0·29, P = 0·025) predicted FRS (R² = 0·613).

CONCLUSIONS

In patients with ACRO, both Cys-C and EAT index might be used as noninvasive predictors of cardiovascular risk.

Cystatin C and Risk of Diabetes and the Metabolic Syndrome - Biomarker and Genotype Association Analyses

Background

We recently reported a relationship between plasma levels of cystatin C and incidence of the metabolic syndrome (MetS) among the first 2,369 subjects who participated in the re-examination study of the population-based Malmö and Diet Cancer Cardiovascular cohort (MDC-CC-re-exam). In this study we aimed to replicate these results and also investigate if cystatin C was causally associated with MetS and diabetes.

Methods

We estimated the effect size of the strongest GWAS derived cystatin C SNP (major allele of rs13038305) on plasma cystatin C in the now completed MDC-CC-re-exam (n = 3,734) and thereafter examined the association between plasma cystatin C (403 cases of diabetes and 2665 controls) as well as rs13038305 (235 cases and 2425 controls) with incident diabetes. The association of rs13038305 and incident MetS (511 cases of MetS and 1980 controls) was similarly investigated in the whole MDC-CC-re-exam. We also attempted to replicate our previously shown association of cystatin C with incident MetS in subjects from the MDC-CC-re-exam (147 cases and 711 controls) that were not included in our previous report.

Results

In the entire MDC-CC-re-exam, each copy of the major allele of rs13038305 was associated with approximately 0.30 standard deviation (SD) higher plasma concentration of cystatin C (β = 0.33, p = 4.2E^-28) in age and sex adjusted analysis. Cystatin C in plasma was not associated with incident diabetes after adjustment for known diabetes risk factors (OR per 1 SD increment 0.99 (0.86–1.13), p = 0.842). In the replication cohort of MDC-CC-re-exam, the OR (95% CI) for incident MetS in subjects belonging to quartiles 1, 2, 3 and 4 of plasma cystatin C levels was 1.00 (reference), 1.21 (0.70–2.07), 1.62 (0.95–2.78) and 1.72 (1.01–2.93) (p_trend = 0.026) in age and sex adjusted analysis. In the entire MDC-CC-re-exam the odds ratio for incident MetS and diabetes per copy of the major rs13038305 allele was 1.13, (0.95–1.34), p = 0.160 and 1.07, 95% CI 0.89–1.30, p = 0.478, respectively.

Conclusion

We were able to replicate our previously shown association between high levels of cystatin C and increased risk of future development of MetS. However, a causal involvement of cystatin C in the etiology of MetS or diabetes seems unlikely since genetic elevation of plasma cystatin C was not significantly related to incidence of these diseases.

Relationship between cystatin C and metabolic syndrome among Chinese premenopausal and postmenopausal women without recognized chronic kidney disease

OBJECTIVE

Although studies have shown that elevated cystatin C (Cys-C) levels are associated with the risk of metabolic syndrome (MetS) in the general population, few studies have examined the relationship between serum Cys-C levels and MetS, stratified by menopause status, among women in China. Therefore, we conducted this study to assess the relationship between Cys-C levels and MetS in Chinese premenopausal and postmenopausal women.

METHODS

We performed a cross-sectional analysis of the baseline data of 1,428 Chinese community-dwelling women who participated in the annual health checkup. MetS was defined by the updated National Cholesterol Education Program/Adult Treatment Panel III criteria. Binary logistic regression analysis was performed to estimate the association between Cys-C levels and MetS. One-way analysis of variance, followed by posttest for linear trends, was performed to evaluate the relationships between Cys-C levels and the number of MetS components. Ordinal regression analysis was used to determine whether menopause status and MetS components contribute to elevated levels of Cys-C.

RESULTS

The mean level of Cys-C was significantly higher in women with MetS than in those without MetS among both premenopausal and postmenopausal women, showing a progressive increase (P for trend < 0.001) in parallel with the progressive increment in the number of MetS components in all women. Higher Cys-C levels were found to be associated with the presence of MetS after adjusting for age, body mass index, and estimated glomerular filtration rate in all women. The higher odds ratio changed little, even after further adjustment for serum blood nitrogen, total cholesterol, low-density lipoprotein cholesterol, drinking status, and smoking status. Elevated Cys-C level was significantly associated with postmenopause status (P = 0.007), increased waist circumference (P = 0.006), and elevated blood pressure (P = 0.025).

CONCLUSIONS

Higher serum Cys-C levels are positively and independently associated with the presence of MetS in Chinese premenopausal and postmenopausal women. Elevated Cys-C levels are significantly associated with postmenopause status.

Relationship between High Serum Cystatin C Levels and the Risk of Gestational Diabetes Mellitus

Aims

Serum cystatin C (CysC) has recently been shown to be associated with the incidence of type 2 diabetes mellitus (T2DM) and progression to the pre-diabetic state. The aim of this study was to explore the relationship between serum CysC and the risk of gestational diabetes mellitus (GDM) in Chinese pregnant women.

Methods

This cross-sectional study consisted of 400 pregnant women including111 with GDM and 289 with normal glucose tolerance at 24–28 weeks of gestation. The subjects were further divided into four groups according to the CysC quartiles, and their clinical characteristics were compared. The serum CysC concentration was measured using immunoturbidimetry and the degree of insulin resistance was assessed by the homeostasis model assessment of insulin resistance (HOMA-IR).

Results

Serum CysC levels were significantly higher in pregnant women with GDM than in the healthy pregnant women[1.0(0.8–1.8) vs 0.7(0.6–1.0), P<0.01). The Spearman’s correlation analysis showed that serum CysC was positively associated with HOMA-IR(r = 0.118, P<0.05) and the occurrence of GDM(r = 0.348, P<0.01). The pregnant women were divided into quartiles according to their serum CysC concentrations. Compared to the first quartile, pregnant women in Q2 (OR, 2.441; P = 0.025), Q3 (OR, 3.383; P = 0.001) and Q4 (OR, 5.516; P<0.001) had higher risk of GDM after adjusted for age, BMI, HbA1c and HOMA-IR. Further, with a rise in the serum CysC, there was an increasing trend in the HOMA-IR levels (P<0.05). A binary logistic regression analysis after adjusting for other confounding variables revealed a significant and independent association between serum CysC and GDM [OR = 14.269; 95% confidence interval, 4.977–40.908, P<0.01].The receiver operating characteristic curve analysis revealed that the optimal cutoff point for serum CysC to indicate GDM was 0.95mg/L.

Conclusions

Serum CysC is significantly and independently associated with insulin resistance and GDM. It may be a helpful biomarker to identify the risk of GDM in Chinese pregnant women.

The Association of Serum Cystatin C with Glycosylated Hemoglobin in Korean Adults

BACKGROUND

Cystatin C has been known to be associated not only with early renal impairment but also with the incidence of diabetic conditions (prediabetes plus diabetes). However, it is not clear whether cystatin C levels are associated with the prevalence of diabetic conditions in Asian populations. We evaluated this association using glycosylated hemoglobin (HbA1c) levels as the definition of diabetes in Korean adults.

METHODS

We analyzed data from 1,559 Korean adults (937 men and 622 women) with available serum cystatin C and HbA1c values.

RESULTS

The serum cystatin C levels in subjects with prediabetes and diabetes were significantly increased (0.91±0.14 mg/L in prediabetes and 0.91±0.17 mg/L in diabetes vs. 0.88±0.13 mg/L in patients with normal glucose levels, P=0.001). At increasing cystatin C levels, the prevalence of subjects with prediabetes (30.2% vs. 14.6%, P<0.001) and those with diabetes (10.6% vs. 8.0%, P<0.001) significantly increased in the group with the highest cystatin C levels. The group with the highest cystatin C levels had a significantly increased odds ratio (OR) for the presence of diabetic conditions compared to the group with the lowest values in total subjects (OR, 2.35; 95% confidence interval [CI], 1.54 to 3.58; P<0.001) and in women (OR, 4.13; 95% CI, 1.97 to 8.65; P<0.001), though there was no significant increase after adjusting for multiple variables.

CONCLUSIONS

Higher levels of serum cystatin C are associated with an increased prevalence of diabetic conditions in Korean adults. Our findings may extend the positive association of cystatin C with diabetes incidence to an Asian population.

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.

Relationship between chronic kidney disease and metabolic syndrome: current perspectives

Both metabolic syndrome (MetS) and chronic kidney disease (CKD) are increasing in incidence and lead to significant cardiovascular morbidity and mortality. The relationship between these two entities is complex. Individual components of the MetS are known risk factors for incident kidney disease, but it is not clear how the clustering of these components is linked to the development and progression of kidney disease. Cross-sectional studies show an association of the MetS and prevalent CKD; however, one cannot draw conclusions as to which came first - the MetS or the kidney disease. Observational studies suggest a relationship between MetS and incident CKD, but they also demonstrate the development of MetS in patients with established CKD. These observations suggest a bidirectional relationship. A better understanding of the relationship between components of the MetS and whether and how these components contribute to progression of CKD and incident cardiovascular disease could inform more effective prevention strategies.

Plasma cystatin-C and risk of developing gestational diabetes mellitus

AIMS

Cystatin-C, a low molecular weight protein, is effectively applied to evaluate the risk of developing renal insufficiency, cardiovascular disorders, neural defects, and inflammatory states. However, the role of this biomarker to monitor different pregnancy-related complications remains controversial.

MATERIALS AND METHODS

In the present study, we compared serum cystatin-C concentration between pregnant women with gestational diabetes mellitus (GDM) and healthy pregnant women to assess value of this biomarker to predict presence of GDM in these women. The study consisted of 60 consecutive pregnant women (30 women suffered GDM and 30 healthy pregnant women) enrolled in Afzalipour hospital in Kerman, Iran in 2012. Fasting blood sample was collected to perform measurements on plasma glucose, lipids, serum creatinine, and C-cystatin. Serum cystatin-C level was quantified using ELISA techniques.

RESULTS

Unadjusted comparison of cystatin-C level between the two study group showed no significant discrepancy between them so that the level of this biomarker in GDM group was 593.00±204.81 mg/L and in healthy group was 531.67±87.52 mg/L (P=0.137); while in multivariable linear model with the presence of associated variables, GDM was a main determinant for increased level of cystatin-C (standardized beta of 0.355, P-value of 0.014).

CONCLUSION

Gestational age was also identified to be another indicator of elevated cystatin-C. In final, our study showed that cystatin-C can be a reliable, useful and promising marker of GDM appearance in pregnant women.

High levels of cystatin C predict the metabolic syndrome: the prospective Malmö Diet and Cancer Study

OBJECTIVE

Cystatin C is a novel marker of cardiovascular disease (CVD); however, the underlying mechanisms remain unclear. Here, we prospectively investigated whether plasma levels of cystatin C predict new-onset metabolic syndrome (MetS) as well as long-term progression and incidence of the different components of the MetS.

METHODS

Cystatin C was measured in 1502 individuals included in the Malmö Diet and Cancer cardiovascular cohort (mean age 56 years, 59% women) who were free from the MetS at baseline and subsequently underwent a follow-up examination after a median of 16 years. MetS was defined according to the NCEP-ATP-III guidelines. Logistic regression was used to adjust for covariates.

MAIN OUTCOME MEASURES

Metabolic syndrome and long-term progression as well as incidence of the different components of the MetS.

RESULTS

During follow-up, 428 subjects developed new-onset MetS. In age- and sex-adjusted analysis, compared with the lowest quartile of cystatin C, the odds ratios (95% confidence interval) for incident MetS in subjects with cystatin C levels in quartiles 2, 3 and 4 were 1.00 (0.71-1.40), 1.48 (1.06-2.07) and 1.91 (1.37-2.68), respectively (Ptrend  < 0.001); this linear association remained significant even after full multivariate adjustment (Ptrend  = 0.041). Interestingly, in this fully adjusted model, long-term progression of abdominal obesity was the only component of the MetS significantly associated with increasing quartiles of baseline cystatin C levels (Ptrend  = 0.008).

CONCLUSION

These findings suggest that cystatin C may adversely affect metabolic factors, particularly abdominal obesity, thus contributing to development of the MetS. Our results may help to explain the link between cystatin C and development of CVD.

The association between cystatin C and incident type 2 diabetes is related to central adiposity

BACKGROUND

Cystatin C has recently been shown to be associated with incident type 2 diabetes. This study aims to validate this association and to study the impact of baseline adiposity.

METHODS

We investigated the 3-year diabetes incidence in 2849 participants from the French Data of an Epidemiological Study on the Insulin Resistance syndrome study, without overt kidney disease. Odds ratios (ORs) associated with cystatin C were adjusted for classical diabetes risk factors and interactions between cystatin C and these risk factors were studied.

RESULTS

Baseline serum cystatin C was significantly associated with incident diabetes on univariate analysis (OR/1 SD of log cystatin C: 1.74; 95% confidence interval [CI] 1.33-2.28; P=0.0001) and after adjustment for age and gender (OR 1.55; 95% CI 1.15-2.10; P=0.0039). This association was independent of serum creatinine-derived measures of baseline renal function and independent of fasting plasma glucose and HbA1c. When body mass index (BMI), waist circumference or baseline insulin resistance index were used as covariates, there was an interaction with cystatin C level. Cystatin C was associated only with incident diabetes for people with BMI, waist circumference or insulin resistance index≥median value with OR (95% CIs), respectively: 1.35 (0.98-1.84, P=0.0625); 1.39 (1.01-1.91, P=0.0441) and 1.41 (1.02-1.94, P=0.0398).

CONCLUSIONS

Cystatin C was associated with 3-year incident diabetes but only in people with central adiposity or insulin resistance. This should be considered in further studies assessing the clinical relevance of its prognostic value.

Cystatin C and asymptomatic coronary artery disease in patients with metabolic syndrome and normal glomerular filtration rate

BACKGROUND

All of the components of metabolic syndrome (MetS) have been regarded as risk factors for coronary artery disease (CAD). Early detection of CAD in asymptomatic patients with MetS remains a challenge. Cystatin C,which has been proposed as a novel marker of renal dysfunction,is correlated with mortality in CAD, The purpose of the study was to evaluate whether cystatin C is a potential marker of asymptomatic CAD in MetS patients with normal kidney function.

METHODS

A total of 211asymptomatic MetS patients without prior history of CAD patients were included in a cross-sectional study. Patients were divided into MetS with asymptomatic CAD (n=136) and MetS without CAD (n=75) groups according to coronary angiograph results. Serum cystatin C levels were measured using particle enhanced immunonephelometric assays. We first assessed whether there is an independent association of cystatin C with the presence and severity of asymptomatic CAD. Then, we investigated the association between cystatin C and other biochemical risk factors for atherosclerosis.

RESULTS

Serum cystatin C levels in patients with asymptomatic CAD were significantly higher than those without CAD (P=0.004). A multiple logistic regression analysis demonstrated cystatin C was independently associated with the presence of asymptomatic CAD (OR=1.326, 95%CI: 1.086-1.619). On receiver operating characteristics (ROC) analysis, the area under the curve (AUC) was 0.622 (95% CI: 0543-0.701, P=0.003), and cystatin C showed a moderate predictive value. Furthermore, cystatin C was independently correlated with Gensini score (standardized β=0.183, P=0.007), and serum cystatin C levels increased with the increasing of number of disease vessels (P=0.005). In a multiple stepwise regression analysis, uric acid (UA)(P<0.001), body mass index (BMI)(P=0.002), triglyceride(TG)(P=0.03), estimated glomerular filtration rate (eGFR)(P<0.001), and fibrinogen(P=0.001) were independently associated with cystatin C.

CONCLUSIONS

Serum cystatin C in our study was significantly associated with the presence and severity of asymptomatic CAD in MetS patients with normal kidney function, suggesting that cystatin C is probably more than a marker of glomerular filtration rate.

Serum cystatin C and the incidence of type 2 diabetes mellitus

AIMS/HYPOTHESIS

To examine the association of serum cystatin C with the incidence of type 2 diabetes mellitus over a 15 year follow-up period.

METHODS

The 15 year cumulative incidence of diabetes was measured in a cohort of Beaver Dam Eye Study participants (n = 3,472, 1988-2003). A person was defined as developing diabetes (a positive history of diabetes mellitus treated with insulin, oral hypoglycaemic agents and/or diet, or elevations in glycosylated haemoglobin levels) in the absence of diabetes at baseline. The relation of cystatin C and other risk factors to incident type 2 diabetes was determined using discrete time extension of the proportional hazards model.

RESULTS

The 15 year cumulative incidence of diabetes was estimated to be 9.6%. After controlling for age, sex, body mass index, smoking status, glycosylated haemoglobin, proteinuria, chronic kidney disease status and hypertension status, serum cystatin C at baseline was associated with the 15 year cumulative incidence of type 2 diabetes (OR per log of cystatin C unit 2.19, 95% CI 1.02-4.68).

CONCLUSIONS/INTERPRETATION

These findings show a positive relationship of serum cystatin C levels with the incidence of type 2 diabetes mellitus independently of confounding risk factors. The findings strongly suggest the need for further evaluation of the potential importance of cystatin C in the pathogenesis of type 2 diabetes mellitus.

Metabolic syndrome and renal injury

Both metabolic syndrome (MetS) and chronic kidney disease (CKD) are major global health issues. Current clinical markers used to reflect renal injury include albuminuria and estimated glomerular filtration rate (eGFR). Given the same eGFR level, urine albumin might be a better risk marker to predict progression of CKD and future development of cardiovascular diseases (CVDs). Serum Cystatin C is emerging as a new biomarker for early detection of renal injury associated with MetS and cardiovascular risk. In addition to each component, MetS per se influences the incidence and prognosis of renal injury and the odds ratios increased with the increase in the number of metabolic abnormalities. Hyperinsulinemia, activation of rennin-angiotensin-aldosterone system, increase of oxidative stress, and inflammatory cytokines are proposed to be the plausible biological link between MetS and CKD. Weight control, stick control of blood pressure, glucose, and lipids disorders may lead to lessening renal injury and even the subsequent CVD.