Serum cystatin C, renal filtration function, and left ventricular remodeling

Correlation of serum homocysteine and cystatin C levels with prognosis in heart failure with preserved ejection fraction patients

OBJECTIVE

This study investigated the relationship of serum homocysteine (Hcy) and cystatin C (Cys C) levels with the prognosis of patients with heart failure with preserved ejection fraction (HFpEF).

METHODS

A total of 178 patients with HFpEF who were admitted to our hospital between December 2019 and November 2020 were included. Patients were grouped based on their serum Hcy and Cys C levels: high Hcy level, normal Hcy level, high Cys C level, and normal Cys C level. Cardiac function, ventricular remodeling indices, and prognosis were compared among patients in these groups. Additionally, the predictive value of serum Hcy and Cys C levels for adverse cardiovascular events in HFpEF patients was analyzed.

RESULTS

Patients' mean age in the high Hcy level, normal Hcy level, high Cys C level, and normal Cys C level groups was 69.21 ± 4.17,67.74 ± 4.28,69.95 ± 4.98, and 67.06 ± 4.13 years old, respectively. The high Hcy level group exhibited a lower proportion of class II cardiac function according to the New York Heart Association (NYHA) classification and a higher proportion of class IV cardiac function than the normal Hcy level group, with statistically significant differences. Similarly, the high Cys C level group had a lower proportion of class II cardiac function and a higher proportion of class IV cardiac function compared with the normal Cys C level group, with statistically significant differences. Left ventricular end-diastolic internal diameter (LVEDD), left ventricular end-systolic internal diameter (LVESD), and left ventricular mass index (LVMI) were significantly higher in both the high Hcy level and high Cys C level groups compared with the normal group, with statistically significant differences. The rates of all-cause mortality and class I endpoint events were significantly higher in the high Hcy level and high Cys C level groups than in the normal group. Multifactorial logistic regression analysis demonstrated that adverse cardiovascular events were significantly associated with cardiac function class, LVEDD, LVESD, LVMI, Hcy, and Cys C in patients with HFpEF. The area under the curve (AUC) values for Hcy and Cys C, determined using receiver operating characteristic (ROC) curve analysis, were 0.778 (optimal critical value, 25.38) and 0.681 (optimal critical value, 1.56), respectively, for predicting adverse cardiovascular events. Both Hcy and Cys C serum levels were positively correlated with LVEDD, LVESD, LVMI, and NYHA classification.

CONCLUSION

Serum levels of Hcy and Cys C were closely associated with cardiac function, ventricular remodeling indices, and prognosis in patients with HFpEF. These levels may serve as valuable indices for assessing HFpEF patients' health status and prognosis, providing important insights into their potential role as biomarkers for HFpEF management and prognosis.

Systematic Review of Kidney Injury Biomarkers for the Evaluation of CKD of Uncertain Etiology

Introduction

Chronic kidney disease of uncertain etiology (CKDu) is an incompletely defined phenotype of chronic kidney disease (CKD) affecting young individuals mostly in agricultural communities in Central America and South Asia. CKDu is a diagnosis of exclusion made in individuals from endemic regions.

Methods

We conducted a systematic review of the primary literature on urinary and plasma kidney injury biomarkers measured in the setting of CKDu (through February 2023). The literature was identified via a Web of Science search and hand search of the references of previously identified literature. Search terms included "CKDu," "Mesoamerican Nephropathy," "CKD of unknown etiology," "Chronic Interstitial Nephritis in Agricultural Communities," "biomarker," "urin∗," and/or "plasma."

Results

A total of 25 papers were included. The 2 most frequently measured biomarkers were urinary kidney injury molecule-1 (KIM-1) and urinary neutrophil gelatinase-associated lipocalin (NGAL). There was substantial variability in study design, laboratory assay methods, and statistical methodology, which prohibited meta-analysis.

Conclusion

Biomarkers that identify tubulointerstitial disease early and accurately may substantially accelerate progress in the study of CKDu and facilitate public health approaches that eventually lead to its prevention and elimination. To date, the literature is limited by relatively small sample sizes and methodological limitations which should be addressed in future studies.

Biomarkers Correspond with Echocardiographic Phenotypes in Heart Failure with Preserved Ejection Fraction: A Secondary Analysis of the RELAX Trial

Background

Little is known about the relationship between structural phenotypes in in heart failure with preserved ejection fraction (HFpEF) and cardiac biomarkers. We used cluster analysis to identify cardiac structural phenotypes and their relationships to biomarkers in HFpEF.

Methods and results

Latent class analysis (LCA) was applied to echocardiographic data including left atrial enlargement (LAE), diastolic dysfunction (DD), E/e', EF≤55%, and right ventricular dysfunction from 216 patients enrolled in the RELAX trial. Three structural phenotypes were identified. Phenotype A had the most grade II DD. Phenotype B had the most grade III DD, worst LAE, elevated E/e' and right ventricular dysfunction. Phenotype C had the least DD and moderate LAE. Phenotypes B and C had prevalent atrial fibrillation (AF). Phenotype B patients had increased carboxy-terminal telopeptide of collagen type I (CITP), cystatin-c (CYSTC), endothelin-1 (ET1), NT-proBNP, and high-sensitivity troponin I (TNI). Type A had the next highest CITP and CYSTC levels while Type C had next highest NT-proBNP.

Conclusions

Structural HFpEF phenotypes demonstrated different characteristics including cardiac biomarkers. These findings may help explain phenotype-specific differences in natural history and prognosis, and they may represent phenotype-specific pathophysiology that could be amenable to targeted therapy.

Circulating extracellular vesicles in human cardiorenal syndrome promote renal injury in a kidney-on-chip system

BACKGROUNDCardiorenal syndrome (CRS) - renal injury during heart failure (HF) - is linked to high morbidity. Whether circulating extracellular vesicles (EVs) and their RNA cargo directly impact its pathogenesis remains unclear.METHODSWe investigated the role of circulating EVs from patients with CRS on renal epithelial/endothelial cells using a microfluidic kidney-on-chip (KOC) model. The small RNA cargo of circulating EVs was regressed against serum creatinine to prioritize subsets of functionally relevant EV-miRNAs and their mRNA targets investigated using in silico pathway analysis, human genetics, and interrogation of expression in the KOC model and in renal tissue. The functional effects of EV-RNAs on kidney epithelial cells were experimentally validated.RESULTSRenal epithelial and endothelial cells in the KOC model exhibited uptake of EVs from patients with HF. HF-CRS EVs led to higher expression of renal injury markers (IL18, LCN2, HAVCR1) relative to non-CRS EVs. A total of 15 EV-miRNAs were associated with creatinine, targeting 1,143 gene targets specifying pathways relevant to renal injury, including TGF-β and AMPK signaling. We observed directionally consistent changes in the expression of TGF-β pathway members (BMP6, FST, TIMP3) in the KOC model exposed to CRS EVs, which were validated in epithelial cells treated with corresponding inhibitors and mimics of miRNAs. A similar trend was observed in renal tissue with kidney injury. Mendelian randomization suggested a role for FST in renal function.CONCLUSIONPlasma EVs in patients with CRS elicit adverse transcriptional and phenotypic responses in a KOC model by regulating biologically relevant pathways, suggesting a role for EVs in CRS.TRIAL REGISTRATIONClinicalTrials.gov NCT03345446.FUNDINGAmerican Heart Association (AHA) (SFRN16SFRN31280008); National Heart, Lung, and Blood Institute (1R35HL150807-01); National Center for Advancing Translational Sciences (UH3 TR002878); and AHA (23CDA1045944).

Update on Assessment of Estimated Glomerular Filtration Rate in Patients With Cirrhosis

Kidney disease is associated with adverse outcomes in patients with cirrhosis including increased post-liver transplantation (LT) mortality. Therefore, diagnosis and staging of kidney disease are critical to timely implementation of treatment and have important implications for transplant eligibility. Serum creatinine (sCr) is a key component of the Model for End-Stage Liver Disease score in LT candidates, and sCr-based estimated glomerular filtration rate (eGFR) values play an important role in determining medical urgency for LT. However, the use of sCr to assess kidney function may be limited in the cirrhotic milieu due to decreased creatinine production, interference of bilirubin with some laboratory assays for sCr, and expansion of the volume of distribution of creatinine. Therefore, conventional eGFR equations perform poorly in patients with cirrhosis and may overestimate kidney function leading to delayed diagnosis of acute kidney injury or lower priority for LT in patients with a truly low glomerular filtration rate. In this review, we will provide an update on the use of sCr for diagnosis and staging of kidney disease in patients with cirrhosis, discuss the limitations of sCr-based eGFR equations, and discuss novel eGFR equations that have been developed in patients with cirrhosis.

Decomposing interaction and mediating effects of race/ethnicity and circulating blood levels of cystatin C on cognitive status in the United States health and retirement study

Background and objectives

Elevated circulating cystatin C is associated with cognitive impairment in non-Hispanic Whites, but its role in racial disparities in dementia is understudied. In a nationally representative sample of older non-Hispanic White, non-Hispanic Black, and Hispanic adults in the United States, we use mediation-interaction analysis to understand how racial disparities in the cystatin C physiological pathway may contribute to racial disparities in prevalent dementia.

Methods

In a pooled cross-sectional sample of the Health and Retirement Study (n = 9,923), we employed Poisson regression to estimate prevalence ratios and to test the relationship between elevated cystatin C (>1.24 vs. ≤1.24 mg/L) and impaired cognition, adjusted for demographics, behavioral risk factors, other biomarkers, and chronic conditions. Self-reported racialized social categories were a proxy measure for exposure to racism. We calculated additive interaction measures and conducted four-way mediation-interaction decomposition analysis to test the moderating effect of race/ethnicity and mediating effect of cystatin C on the racial disparity.

Results

Overall, elevated cystatin C was associated with dementia (prevalence ratio [PR] = 1.2; 95% CI: 1.0, 1.5). Among non-Hispanic Black relative to non-Hispanic White participants, the relative excess risk due to interaction was 0.7 (95% CI: -0.1, 2.4), the attributable proportion was 0.1 (95% CI: -0.2, 0.4), and the synergy index was 1.1 (95% CI: 0.8, 1.8) in a fully adjusted model. Elevated cystatin C was estimated to account for 2% (95% CI: -0, 4%) for the racial disparity in prevalent dementia, and the interaction accounted for 8% (95% CI: -5, 22%). Analyses for Hispanic relative to non-white participants suggested moderation by race/ethnicity, but not mediation.

Discussion

Elevated cystatin C was associated with dementia prevalence. Our mediation-interaction decomposition analysis suggested that the effect of elevated cystatin C on the racial disparity might be moderated by race/ethnicity, which indicates that the racialization process affects not only the distribution of circulating cystatin C across minoritized racial groups, but also the strength of association between the biomarker and dementia prevalence. These results provide evidence that cystatin C is associated with adverse brain health and this effect is larger than expected for individuals racialized as minorities had they been racialized and treated as non-Hispanic White.

Predictive Value of the Serum Cystatin C/Prealbumin Ratio in Combination With NT-proBNP Levels for Long-Term Prognosis in Chronic Heart Failure Patients: A Retrospective Cohort Study

Aim: The present study was established to investigate the use of the serum cystatin C/prealbumin (Cys-C/PAB) ratio as a predictive factor for long-term prognosis in patients with chronic heart failure.

Methods: We divided our retrospective cohort of 6,311 patients admitted to hospital due to an episode of heart failure (HF) into three groups according to the Cys-C/PAB ratio. The endpoints were cardiovascular and all-cause mortality. Median follow-up time were 3.3 years (2–8 years), during which 2,945 (46.7%) patients died.

Results: The Cys-C/PAB ratio was revealed to be an independent predictor of cardiovascular mortality (HR: 1.12, 95% CI: 1.15–1.23, P < 0.01) and all-cause mortality (HR: 1.19, 95% CI: 1.13–1.24, P < 0.01) by multivariable Cox analysis. Integrated discrimination improvement (IDI) showed that the Cys-C/PAB ratio in conjunction with the level of N-terminal pro-B-type natriuretic peptide (NT-proBNP) conferred a significant improvement in predicting individual risks of cardiovascular (P = 0.023) and all-cause (P = 0.028) mortality. For those with a high Cys-C/PAB ratio in combination with a high NT-proBNP level, the long-term cardiovascular mortality risk ratio was 8.6-times higher than for those with low values, and 7.51-times for all-cause mortality. Our study also showed that Cys-C/PAB and NT-proBNP in combination displayed higher value for the prediction of cardiovascular and all-cause in-hospital mortality in patients with HF.

Conclusions: The Cys-C/PAB ratio is valuable for predicting cardiovascular and all-cause mortality in patients with HF and offers additional information to that provided by NT-proBNP.

Association Between Cystatin C and Cardiac Function and Long-Term Prognosis in Patients with Chronic Heart Failure

BACKGROUND The aim of this study was to investigate the association between cystatin C and cardiac function and long-term prognosis in patients with chronic heart failure (CHF). MATERIAL AND METHODS We selected 418 CHF patients admitted to our hospital as subjects. Patients were divided into 3 groups according to the cystatin C level (Quantile 1 group: 0.65-1.04 mg/L, Quantile 2 group: 1.05-1.35 mg/L, and Quantile 3 group: 1.36-7.84 mg/L), and patients were followed up for 5 years. We used odds ratio (OR) and 95% confidence interval (CI) to compare the results. RESULTS The cystatin C and NT-ProBNP level in the cardiac function grade (NYHA) class IV group were higher than those in the class III group (P<0.05). Pearson correlation analysis showed that there was a positive correlation between cystatin C and NT-ProBNP log₁₀ transform in CHF patients (r=0.411). During 5-year follow-up, 231 patients died and the 5-year all-cause mortality rate was 55.26% (231/418). There was a significant difference in 5-year all-cause mortality among the 3 groups (P for trend=0.010). After adjusting for potential confounders by multivariate regression analysis, the Quantile 2 group vs. Quantile 1 group were OR=0.83, 95% CI 0.51 to 1.35, P=0.448, and the Quantile 3 group vs. Quantile 1 group were OR=1.71, 95% CI. 1.04 to 2.82, P=0.034. Curve fitting showed that cystatin C was positively correlated with 5-year all-cause mortality in CHF patients. CONCLUSIONS Cystatin C was positively correlated with cardiac function and NT-ProBNP in CHF patients. Cystatin C could be used as a serological index to evaluate the long-term prognosis of CHF patients.

Association of renal artery stenosis with left ventricular remodeling in patients coexisting with renovascular and coronary artery disease

OBJECTIVE

Data about renal artery stenosis association with left ventricular remodeling in patients coexisting with coronary artery disease are scanty.

METHODS

Patients with suspected both coronary artery disease and renal artery stenosis undergoing coronary and renal arteriography between October 2013 and December 2015 were prospectively enrolled. Left ventricular remodeling patterns were compared among different severity of renal artery stenosis group. Logistic regression was done to investigate the determinants of the left ventricular morphology.

RESULTS

The overall prevalence of left ventricular hypertrophy was 40.5%, the highest in bilateral renal artery stenosis group compared to unilateral or normal ones (65.4% versus 41.8% versus 34.8%, p = 0.012). Significantly lower estimated glomerular filtration rate and higher cystatin C level were found in bilateral renal artery stenosis group than that in other two groups. Multivariate regression analysis showed that bilateral renal artery stenosis was associated with increased left ventricular hypertrophy and concentric hypertrophy with statistical significance (adjusted odds ratio = 2.909 (95%CI: 1.063-7.961), and 3.021 (95%CI: 1.136-8.033)). In addition, estimated glomerular filtration rate level was also related to left ventricular hypertrophy, while there was no significant interaction between renal artery stenosis and coronary artery disease on left ventricular hypertrophy/concentric hypertrophy occurrence.

CONCLUSIONS

Bilateral renal artery stenosis is significantly associated with increased left ventricular hypertrophy/concentric hypertrophy in patients with suspected concomitant coronary and renal artery disease, while no synergic effect could be found in coronary artery disease.

Serum neutrophil gelatinase-associated lipocalin and cystatin C are diagnostic markers of renal dysfunction in older patients with coronary artery disease

Objective

This study aimed to assess the diagnostic value of serum neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C for renal dysfunction in older patients with coronary disease.

Methods

A total of 84 older patients with coronary artery disease were included in this study. Serum NGAL and cystatin C levels were analysed using commercially available kits. Medical data of all patients were recorded and analysed.

Results

NGAL and cystatin C levels were significantly positively correlated with N-terminal prohormone of brain natriuretic peptide levels and negatively correlated with the estimated glomerular filtration rate. The areas under the receiver operating characteristic curves of serum NGAL and cystatin C levels for diagnosing early renal dysfunction were 0.884 and 0.744, respectively.

Conclusion

Serum NGAL and cystatin C are potential early and sensitive markers of renal dysfunction in older patients with coronary artery disease.

Absence of cystatin C involvement in ventricular remodelling and heart failure

Cystatin C (CysC) is a protease encoded by housekeeping genes. Although its prognostic value in heart failure (HF) is well known, it is debatable whether this value is due to the greater accuracy of CysC in calculating the glomerular filtration rate or to its involvement in pathological ventricular remodelling. The aim of this study was to determine whether CysC expression changes in the myocardium of foetuses of different ages and in the myocardium of adults with various cardiovascular diseases, as well as to analyse the correlation between its serum concentrations and cardiac structure and morphology in a patient group with HF.

PATIENTS AND METHODS

We analysed the correlations (Pearson's r and Spearman's test) between the serum CysC levels and echocardiographic parameters of 351 patients with HF. We also performed immunohistochemical staining for CysC, metalloproteinase-9 (MMP-9) and desmin in 9 cardiac tissue samples from autopsies of 4 foetuses of different gestational ages and 5 healthy adults or adults with cardiovascular disease.

RESULTS

For the patients with HF, there was no correlation between the CysC concentrations and the cardiac parameters measured by 2D echocardiography. The immunohistochemistry showed a weak background staining for CysC in all samples, regardless of age and the presence or absence of cardiovascular diseases.

CONCLUSIONS

Our results suggest that CysC does not have a significant role in the pathological remodelling of the left ventricle in HF.

Limited value of cystatin-C over estimated glomerular filtration rate for heart failure risk stratification

Background

To compare the prognostic value of estimated glomerular filtration rate, cystatin-C, an alternative renal biomarker, and their combination, in an outpatient population with heart failure.Estimated glomerular filtration rate is routinely used to assess renal function in heart failure patients. We recently demonstrated that the Cockroft-Gault formula is the best among the most commonly used estimated glomerular filtration rate formulas for predicting heart failure prognosis.

Methodology/Principal Findings

A total of 879 consecutive patients (72% men, age 70.4 years [P_25–75 60.5–77.2]) were studied. The etiology of heart failure was mainly ischemic heart disease (52.7%). The left ventricular ejection fraction was 34% (P_25–75 26–43%). Most patients were New York Heart Association class II (65.8%) or III (25.9%). During a median follow-up of 3.46 years (P_25–75 1.85–5.05), 312 deaths were recorded. In an adjusted model, estimated glomerular filtration rate and cystatin-C showed similar prognostic value according to the area under the curve (0.763 and 0.765, respectively). In Cox regression, the multivariable analysis hazard ratios were 0.99 (95% CI: 0.98–1, P = 0.006) and 1.14 (95% CI: 1.02–1.28, P = 0.02) for estimated glomerular filtration rate and cystatin-C, respectively. Reclassification, assessed by the integration discrimination improvement and the net reclassification improvement indices, was poorer with cystatin-C (−0.5 [−1.0;−0.1], P = 0.024 and −4.9 [−8.8;−1.0], P = 0.013, respectively). The value of cystatin-C over estimated glomerular filtration rate for risk-stratification only emerged in patients with moderate renal dysfunction (eGFR 30–60 ml/min/1.73 m², chi-square 12.9, P<0.001).

Conclusions/Significance

Taken together, the results indicate that estimated glomerular filtration rate and cystatin-C have similar long-term predictive values in a real-life ambulatory heart failure population. Cystatin-C seems to offer improved prognostication in heart failure patients with moderate renal dysfunction.

Cardiorenal syndromes: pathophysiology to prevention

There is a strong association between both acute and chronic dysfunction of the heart and kidneys with respect to morbidity and mortality. The complex interrelationships of longitudinal changes in both organ systems have been difficult to describe and fully understand due to a lack of categorization of the common clinical scenarios where these phenomena are encountered. Thus, cardiorenal syndromes (CRSs) have been subdivided into five syndromes which represent clinical vignettes in which both the heart and the kidney are involved in bidirectional injury and dysfunction via a final common pathway of cell-to-cell death and accelerated apoptosis mediated by oxidative stress. Types 1 and 2 involve acute and chronic cardiovascular disease (CVD) scenarios leading to acute kidney injury (AKI) or accelerated chronic kidney disease (CKD). Types 3 and 4 describe AKI and CKD, respectively, leading primarily to heart failure, although it is possible that acute coronary syndromes, stroke, and arrhythmias could be CVD outcomes in these forms of CRS. Finally, CRSs type 5 describe a systemic insult to both heart and the kidneys, such as sepsis, where both organs are injured simultaneously in persons with previously normal heart and kidney function at baseline. Both blood and urine biomarkers, including the assessment of catalytic iron, a critical element to the generation of oxygen-free radicals and oxidative stress, are reviewed in this paper.

Differential prognostic utility of NTproBNP and Cystatin C in patients with acute exacerbation of chronic pulmonary disease

Objectives

To determine whether serum Cystatin C (CysC) and NTproBNP have prognostic value among patients with long-standing chronic lung disease.

Design

Prospective, observational, non-interventional study.

Setting

CysC and NTproBNP are prognostic markers in several cardiac conditions. In addition, CysC acts as an antiprotease following Cathepsin activation, which has been involved in the pathogenesis of chronic obstructive pulmonary disease.

Participants

Patients with a basal functional status of II-IV (NYHA), admitted for an acute exacerbation of chronic pulmonary diseases and no previous history of symptoms related to pulmonary hypertension or heart failure.

Main outcome measures

NTproBNP and CysC were determined at admission in 107 patients with acute exacerbation of chronic lung disease. During 12-month follow-up, mortality, new hospital admissions and prescription of diuretics were recorded.

Results

During follow-up there were eight patient deaths (7.5%). Mean NTproBNP among the deceased was 1510.20 pg/mL (95% CI 498.44–4628.55) vs 502.70 pg/mL (95% CI 395.44–645.48) among survivors (p = 0.01). Twenty-seven patients (25%) were prescribed loop diuretics. Mean concentration of CysC was 1.45 mg/dL (95% CI 1.21–1.69 mg/dL) vs 1.17 mg/dL (95% IC 1.09–1.25 mg/dL) in those not prescribed (p = 0.004). NTproBNP concentration was 837.14 pg/mL (95% CI 555.57–1274.10 pg/mL) in patients prescribed diuretics vs 473.42 pg/mL (95% CI 357.80–632.70 pg/mL) in those not prescribed (p = 0.03). Kaplan-Meier analysis revealed a significant difference between death and diuretic prescription during follow-up when cut-off value for NTproBNP was 550 pg/mL (p = 0.03 and p = 0.02, respectively). For 1.16mg/dL of CsysC, a significant difference was only observed in diuretic prescription (p = 0.007).

Conclusions

In patients with chronic respiratory diseases NTproBNP has predictive value in terms of mortality whereas CysC does not. However, it is still possible that both can contribute to the early identification of patients at risk of developing clinical ventricular dysfunction.