An electrochemical immunosensor for sensitive and rapid detection of cystatin C based on Fe3O4/AuNPs-MWCNTs@PDA nanocomposite.

Serum Cystatin C (CysC) is an impressive marker for early diagnosis of renal dysfunction. In this work, we established a novel electrochemical immunosensor based on Fe3O4/AuNPs-MWCNTs@PDA nanocomposite for the detection of CysC. The Fe3O4/AuNPs-MWCNTs@PDA nanozyme complex by polydopamine encapsulation can not only carry massive detection antibodies, but also bind the electroactive substance toluidine blue (TB) through electrostatic adsorption. By immobilizing AuNPs onto the electrode to bind the capture antibody (Ab1), we constructed a sandwich electrochemical immunosensor with low cost, high sensitivity, and repeatability. The detection range is 3.9-125.0 ng/mL with a significant linear relationship between the current peak difference (ip) and logarithm of the CysC concentration. Moreover, the detection limit of the immunosensor is 0.157 ng/mL. We have successfully utilized this novel immunosensor to detect CysC in human serum samples, and these results have implications for its potential use in clinical application.

Assessment of the renal function of patients with anorexia nervosa.

BACKGROUND: A decreased glomerular filtration rate (GFR), estimated using creatinine (Cr- eGFR), is often found at the initial presentation of anorexia nervosa (AN). Its pathophysiology has been explained mainly by dehydration, and chronic hypokalemia is also thought to be a cause. However, because we have often experienced cases of AN with decreased Cr-eGFR without these conditions, we must consider different etiologies. The focus of this paper is on low free triiodothyronine (FT3) syndrome. We also discuss the utility of eGFR, estimated using cystatin-C (CysC-eGFR), for these patients. METHODS: The data of 39 patients diagnosed with AN between January 2005 and December 2023 was available for study. The characteristics of patients at the lowest and highest body mass index standard deviation score (BMI-SDS) were examined. Data on the parameters Cr-eGFR, CysC-eGFR, dehydration markers, potassium (K), and hormonal data and BMI-SDS were assessed during the treatment course to evaluate the correlations in these parameters. Blood hematocrit, uric acid (UA), blood urine nitrogen (BUN) level, and urine specific gravity were adopted as dehydration markers; FT3, free thyroxine, thyroid stimulating hormone, and insulin-like growth factor were adopted as hormonal data. Cr-eGFR and simultaneously evaluated dehydration markers, K, or hormonal data were extracted and correlations associated with the changes in BMI-SDS were examined. Furthermore, Cr-eGFR and simultaneously assessed CysC-eGFR were compared. RESULTS: When the BMI-SDS was at the lowest value, low-FT3 syndrome was shown. Severe hypokalemia was not found in our study. A linear relation was not found between Cr-eGFR and BMI-SDS. A statistically significant correlation was found between Cr-eGFR and FT3 (p = 0.0025). Among the dehydration markers, statistically significant correlations were found between Cr-eGFR and BUN or UA. The difference between Cr-eGFR and CysC-eGFR was prominent, and CysC-eGFR showed much higher values. CONCLUSIONS: Our data indicates that low-FT3 syndrome and dehydration were related to the renal function of our patients with AN. Furthermore, our data suggest that caution is needed in the interpretation of kidney function evaluation when using CysC-eGFR in cases of AN.

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.

Challenges of Renal Function Assessment in Breast Cancer Patients Treated With Abemaciclib: A Case Report.

Abemaciclib, a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor used for hormone-receptor-positive and human epidermal growth factor receptor 2 (HER-2)-negative breast cancer, can lead to elevated serum creatinine without implications on the true renal function. Although clinical trials have shown no increase in other kidney function biomarkers, this may still represent a challenge in cancer patients. We report a case of a 74-year-old female who presented with creatinine and cystatin-C elevation during treatment with abemaciclib without an equivalent decrease in measured glomerular filtration rate (GFR) with renal scintigraphy. The confirmation of adequate kidney function allowed for the maintenance of treatments that would otherwise be limited by renal impairment. Healthcare providers should be aware of abemaciclib's effect on serum creatinine but should not eliminate the possibility of actual kidney injury. Alternative biomarkers for GFR assessment are recommended, although the usefulness of cystatin-C in patients receiving abemaciclib should be investigated in greater depth.

CKD Prevalence and Incidence in Older Adults Using Estimated GFR With Different Filtration Markers: The Atherosclerosis Risk in Communities Study.

Rationale & Objective: The prevalence of chronic kidney disease (CKD) is known to increase with age; however, creatinine may be a less reliable filtration marker in older adults. Few studies have investigated the prevalence and progression of CKD using different filtration markers for estimating glomerular filtration rate (GFR). Study Design: A prospective observational cohort study. Setting & Participants: 6,393 White and African American participants aged 65-100 years from the Atherosclerosis Risk in Communities Study (ARIC) at Visit 5, followed longitudinally at Visits 6 and 7. Exposure and Outcome: The eGFR was estimated either by creatinine (eGFRcr), cystatin C (eGFRcys), creatinine and cystatin C (eGFRcr-cys), or using creatinine, cystatin C, and ß-2-microglobulin (eGFRcr-cys-b2m). CKD progression was defined as 30% decline in eGFR at follow-up visits. Analytical Approach: Logistic regression models, adjusted for sex, race and study center, diabetes, blood pressure, body mass index, prevalent cardiovascular disease, and heart failure. Results: At Visit 5, the mean age in the study population was 75.8 years, and the mean eGFR ranged from 71.2 to 61.2 mL/min/1.73m2 using eGFRcr or eGFRcys, respectively. The proportion with eGFR < 60 mL/min/1.73m2 was lowest with eGFRcr and highest with eGFRcys for all age groups, and prevalence increased with age for all markers. For example, the prevalence of eGFRcr < 60 mL/min/1.73m2 in ages 70-74 years ranged from 15% to 21% and in ages 85-89 years ranged from 38% to 46% at the different visits. The proportion with a 30% eGFR decline over a mean of 8 years in people who were originally aged 65-69 years ranged from 9% (eGFRcr)-18% (eGFRcys). More people with eGFRcr ≥ 60 mL/min/1.73m2 were reclassified to < 60 mL/min/1.73m2 when using eGFRcys (33%) compared with eGFRcr-cys (12%) or eGFRcr-cys-b2m (18%). The proportion with 30% eGFR decline was lowest with eGFRcr and highest with eGFRcys, with greater incidence in older age groups for all markers. Limitations: No direct measurement of GFR. Not all participants survived or attended subsequent follow-up visits. Conclusions: The prevalence and progression of CKD increase with age, but estimates vary with the filtration marker used. The eGFRcr gave the lowest estimate of CKD at 15% for people aged 65-69 years at Visit 5 while eGFRcys gave the highest estimates of CKD at 26% for that same population.

The study examines different filtration markers for glomerular filtration rate (GFR) equations in older adults. Filtration markers can be affected by age-varying characteristics like muscle mass, so it is important to investigate potential discrepancies in eGFR with different markers. We evaluated eGFR using creatinine, cystatin C, both, and alongside ß-2-microglobulin to determine kidney disease prevalence and progression. The main takeaway from this study is that there is variation in prevalence of kidney disease in older adults depending on what filtration marker is used in estimating GFR. Our study falls in line with international kidney guidelines to measure cystatin C more in clinical care, as we may be missing some older adults with kidney disease.

Absolute quantitation of human serum cystatin C: candidate reference method by 15N-labeled recombinant protein isotope dilution UPLC-MS/MS.

OBJECTIVES: Serum cystatin C (CysC) is a reliable and ideal endogenous marker for accurately assessing early changes in glomerular filtration rate (GFR), surpassing the limitations of creatinine-based estimated GFR. To improve the precision of GFR calculation, the development of strategies for accurately measuring serum CysC is crucial. METHODS: In this study, the full-length CysC pure product and fully recombinant 15N-labeled CysC internal standard were subjected to protein cleavage. Subsequently, an LC-MS/MS method was developed for the absolute quantification of serum CysC. The traceability of the method was assigned calibrator using the amino acid reference measurement procedure (RMP). It involved calibrating the instrument using an amino acid reference material with known amino acid concentrations for calibration and comparison purposes. RESULTS: The total imprecision of the method was determined to be ≤8.2 %, and a lower functional limit of quantification (LLoQ) was achieved. The recoveries ranged from 97.36 to 103.26 %. The relative bias between this candidate RMP for measurement of ERM-DA471-IFCC and the target value was 1.74 %. The linearity response was observed within the concentration range of 0.21-10.13 mg/L, with a high R2 value of 0.999. The results obtained using our method was consistent with those obtained using other certified RMPs. CONCLUSIONS: With the establishment of this highly selective and accurate serum CysC measurement method, it is now possible to assess the correlation between immunoassay results of serum CysC and the intended target when discrepancies are suspected in the clinical setting.

Effectiveness of sarcopenia screening markers in predicting out-of-hospital death in the oldest (≥80 years) older.

OBJECTIVE: The goal of this investigation was to elucidate the correlation between sarcopenia screening indicators (aspartate transaminase/alanine transaminase (AST/ALT) and creatinine/cystatin C*100 (Cr/CysC*100)) and the risk of out-of-hospital (OFH) death among the very advanced age (≥80 years) population. METHODS: We conducted a retrospective cohort investigation, involving internal medicine inpatients aged ≥80 years of age, who sought treatment at a teaching hospital in western China. We obtained OFH mortality information from telephonic interviews. Subsequently, we employed Cox proportional hazards models to analyze the links between AST/ALT and Cr/CysC*100 and OFH all-cause mortality among the very advanced age (≥80 years old) population. RESULTS: In all, we recruited 398 subjects, among which 51.51% were male. The median age of OFH deceased male patients was 85 years, and the same for female patients was 87 years. The total quantity of OFH deaths was 164 (41.21%). Among the oldest male population, those who died OFH exhibited enhanced AST/ALT, relative to those who survived (death vs. survival: 1.5 vs 1.3, P=0.008). However, among the oldest female, there was no difference in AST/ALT between patients who expired OFH, and those who survived. Among the oldest elders (male and female), Cr/CysC*100 did not significantly differ between surviving and OFH deceased patients. Additional analysis involving the Cox proportional hazards model revealed that among the oldest male population, an enhanced AST/ALT denoted an augmented risk of OFH death (hazard ratios (HRs) =1.797, 95%CI: 1.2-2.691). However, Cr/CysC*100 was not correlated with OFH mortality risk. Among the oldest female population, neither AST/ALT nor Cr/CysC*100 was correlated with OFH mortality risk. CONCLUSIONS: Enhanced AST/ALT was correlated with an augmented OFH mortality risk among the oldest male, but not female population. Alternately, Cr/CysC*100 was not linked to OFH mortality risk among any population.

Sex and Age Influence the Relationship Between Serum Creatinine/Cystatin C and Carotid Plaque in Patients With Type 2 Diabetes Mellitus.

We investigated the effect of sex and age on the association between serum creatinine/cystatin C (CCR) ratio and carotid plaque in patients with type 2 diabetes mellitus (T2DM). The carotid plaque group and the non-plaque group were divided according to cervical vascular ultrasound; the general and biochemical data of the two groups were compared according to CCR, gender, and age. Binary logistic regression was used to analyze the factors influencing carotid plaque. A total of 1429 patients with T2DM were included in this study. On multivariate analysis, CCR was an independent predictor of carotid plaque with an adjusted odds ratio (OR) of 1.681 [1.250-2.260]. The risk of carotid plaque in men with T2DM increased significantly (P < .05) with decreasing levels of CCR. In addition, an association between CCR and carotid plaque was found in individuals with T2DM <65 years of age (P < .05). CCR is strongly associated with the risk of carotid plaques in persons with T2DM and are an independent risk factor for carotid plaques in men and people aged <65 years with T2DM.

[Current clinical application of glomerular filtration rate assessment methods in pediatric populations]. / 肾小球滤过率评估方法在儿童人群中的应用现状.

Glomerular filtration rate (GFR) is a critical indicator of renal function assessment, which exhibits age-dependency in children and may differ from adults under various disease conditions. In recent years, there has been a growing focus on GFR among scholars, with an increasing number of clinical studies dedicated to refining and optimizing GFR estimation to span all pediatric age groups. However, the methods and assessment equations for estimating GFR may vary under different disease conditions, affecting the accuracy and applicability of assessments. This article reviews the peculiarities of renal function in children, explores GFR measurement methods, and evaluates the application of various GFR assessment equations in pediatric clinical practice, providing a reference for clinical assessment of renal function in children.

Human and Mouse Nephrin and Their Interactions With 13 Proteins: An In Silico Study.

Background Human nephrin (hNeph) (podocyte protein) has been known to be involved in both the formation and maintenance of the slit diaphragm (SD) and also acts as a hub protein in the podocyte by modulating cell polarity, cell survival, cell adhesion, cytoskeletal organization, mechano-sensing, and SD turn-over. Methodology In the present investigation, we aimed to analyse the hNeph and mouse nephrin (mNeph) and their interactions with 13 proteins using the molecular docking method. The 13 selected human proteins which include matrix metalloproteinases (MMP 2 and 9), retinol-binding proteins (RBP 3 and 4), kallikrein 1 (KLK 1), uromodulin, insulin-like growth factor binding protein 7 (IGFBP7), cystatin C, podocin, beta arrestin 1, vang-like protein 2 (VANGL2), dynamin 1, and tensin-like C1 domain-containing phosphatase (TENC1) were studied on the docking analysis of hNeph and mNeph by using the HDOCK (protein-protein) docking method. In addition, the physicochemical (PC) properties of 15 proteins were performed using the ProtParam web server. Results In the present investigation, five chosen human proteins, namely, IGFBP7, cystatin C, podocin, VANGL2, and TENC1, have exhibited theoretical isoelectric point (PI) values greater than 7.0. The protein-protein docking analysis has shown that hKLK and hVANGL2 exhibited the maximum docking score of -206.39 kcal/mol and -329.28 (kcal/mol) with the target proteins mNeph and hNeph, respectively. Conclusions Thus, the current finding highlights the interactions of hNeph and mNeph with 13 chosen proteins, which may help in renal disease management.

How to Assess the Glomerular Filtration Rate, and Which Method is Deemed Most Reliable?

The prevalence of chronic kidney disease (CKD) continues to rise globally, paralleled by an increase in associated morbidity and mortality, as well as significant implications for patient quality of life and national economies. Chronic kidney disease often progresses unrecognized by patients and physicians, despite diagnosis relying on two simple laboratory measures: estimated glomerular filtration rate (eGFR) and urine analysis. GFR measurement has been grounded in renal physiology, specifically the concept of clearance, with creatinine identified as a suitable endogenous marker for estimating creatinine clearance (CrCl). On this foundation, various equations have been developed to calculate CrCl or estimated GFR (eGFR) using four variables that incorporate creatinine and certain demographic information, such as sex and age. However, creatinine measurement requires standardization to minimize assay variability across laboratories. Moreover, the accuracy of these equations remains contentious in certain patient subgroups. For these reasons, additional mathematical models have been devised to enhance CrCl estimation, for example, when urine collection is impractical, in elderly or debilitated patients, and in individuals with trauma, diabetes, or obesity. Presently, eGFR in adults can be immediately measured and reported using creatinine-based equations traceable through isotope dilution mass spectrometry. In conclusion, leveraging insights from renal physiology, eGFR can be employed clinically for early diagnosis and treatment of CKD, as well as a public health tool to estimate its prevalence.

The predictive value of the triglyceride glucose index combined with cystatin C for the prognosis of patients with acute coronary syndrome.

Background: Recent studies have shown that the triglyceride glucose index (TyG) and cystatin C (CysC) are closely related to cardiovascular disease, but there is limited research on the prognosis of patients with acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI). The aim of this study was to explore the predictive value of the combination of the TyG index and CysC in predicting major adverse cardiovascular events (MACEs) in ACS patients who underwent PCI. Methods: This retrospective study included 319 ACS patients who underwent PCI. The clinical endpoint was the occurrence of MACEs, including all-cause mortality, heart failure, non-fatal myocardial infarction, target vessel revascularization, and angina requiring hospitalization. Patients were classified into MACEs (65 cases) and non-MACEs (254 cases) groups. Univariate factor and multivariate analysis were used to identify predictors of MACEs. The receiver operating curve (ROC) of the prediction model of MACEs was determined. Additionally, the net reclassification improvement and integrated discrimination improvement indexes were calculated to further assess the additional predictive value of the risk factors for MACEs. Subgroup and interaction analysis between the TyG index combined with CysC and MACEs were conducted in various subgroups. Patients were stratified according to the optimal cutoff point value of the TyG index and the CysC determined by ROC curve analysis. The Kaplan-Meier analysis method was used to construct a survival curve 1 year after PCI. Results: During a median follow-up period of 14 months, 65 (20.38%) patients had experienced at least one primary endpoint event. Multivariate logistic regression analysis indicated that the TyG index and CysC were independently associated with an increased risk of MACEs after PCI (OR, 2.513, 95% CI 1.451-4.351, P= 0.001; and OR, 4.741, 95% CI 1.344-16.731, P=0.016, respectively). The addition of the TyG index and CysC to the baseline risk model had the strongest incremental effect for predicting MACEs in terms of the C-statistic from 0.789 (95% CI 0.723-0.855, P<0.001) to 0.799 (95% CI 0.733-0.865, P<0.001). Furthermore, Kaplan-Meier analysis demonstrated that a TyG index greater than 9.325 and a CysC value greater than 1.065 mg/ml were significantly associated with an increased risk of MACEs (log-rank, all P < 0.01). Conclusion: The TyG index predicts MACEs after PCI in patients with ASC independent of known cardiovascular risk factors. Adjustment of the CysC by the TyG index further improves the predictive ability for MACEs in patients with ACS undergoing PCI. Thus, both of them are expected to become new prognostic indicators for MACEs in patients with ACS after PCI.

Creatinine-to-cystatin C ratio and frailty in older adults: a longitudinal cohort study.

BACKGROUND: Creatinine-to-cystatin C ratio (CCR) has been associated with multiple adverse outcomes. However, little is known about its relationship with frailty. We aimed to explore the association between CCR and frailty among older adults. METHODS: A total of 2599 participants aged ≥ 60 years (mean age 67.9 ± 6.0 years, 50.4% males) were included from the China Health and Retirement Longitudinal Study (2011-2015). Baseline CCR was calculated as plasma creatinine (mg/dL) / cystatin C (mg/L) × 10 and was grouped by quartiles. Frailty was evaluated by the validated physical frailty phenotype (PFP) scale and was defined as PFP score ≥ 3. The generalized estimating equations model was used to explore the relationship between CCR and frailty. RESULTS: The frailty risk decreased gradually with increasing CCR in the quartiles (P for trend = 0.002), and the fourth CCR quartile was associated with a significantly lower risk of frailty compared with the lowest quartile (odds ratio [OR] 0.37, 95% confidence interval [CI] 0.19-0.70). When modeling as a continuous variable, per 1-unit increase in CCR was related to 17% decreased odds of frailty (OR 0.83, 95% CI 0.74-0.93). The association was consistent in male and female participants (P for interaction = 0.41). Poisson models revealed that frailty score was negatively associated with CCR (ß= -0.11, 95% CI= -0.19 to -0.04), and sex did not significantly moderate the associations (P for interaction = 0.22). The results were not affected by further adjusting for high-sensitivity C-reactive protein. Similar results were observed by analyses with multiple imputation technique and analyses excluding participants with baseline frailty. CONCLUSIONS: Higher CCR was associated with a lower frailty risk. CCR may be a simple marker for predicting frailty in older adults.

Association of serum cystatin C level and major adverse cardiovascular events in patients with percutaneous coronary intervention.

Background: Recurrent acute myocardial infarction requiring unplanned percutaneous coronary intervention (PCI) is one of the major adverse cardiovascular events (MACEs) in patients with acute coronary syndrome (ACS) after PCI. There is a continuing controversy about the association between serum cystatin C, a biomarker for the evaluation of renal function, and the prognosis of ACS patients following PCI. The retrospective study evaluated the association between serum cystatin C level and MACE in ACS patients after PCI. Methods: Data were retrieved for 330 patients with ACS for primary PCI in a single center. Serum cystatin C levels were measured before PCI. All patients underwent regular follow-ups after PCI, and the studied endpoint was MACE, defined as the need for a repeat revascularization in the heart. The predictive value of serum cystatin C for MACE was analyzed using univariate and multivariate analysis. Restricted cubic spline (RCS) analysis was applied to evaluate the dose-response relationship between serum cystatin C level and MACE in ACS patients following PCI. Results: After a median follow-up of 63 months (range, 1-148 months), 121 of the 330 patients experienced MACE. Compared to patients who did not have MACE, patients who had MACE showed a significant decrease in serum cystatin C levels (0.99±0.32 vs. 1.15±0.78 mg/L, P=0.03). In multivariate regression analysis, serum cystatin C level was an independent risk factor for MACE. According to the serum cystatin C level, patients were divided into 4 categories, Cox regression analysis illustrated that the second quartile of serum cystatin C level indicated an increased risk of MACE in patients with PCI for primary ACS compared to the highest quartile [Q2: adjusted hazard ratio (HR) =2.109; 95% confidence interval (CI): 1.193-3.727; P=0.01]. RCS analysis showed a significant U-shaped dose-response relationship between cystatin C level and MACE in patients with PCI for ACS (P for non-linearity =0.004). Conclusions: These results indicated an association between serum cystatin C level and post-PCI MACE in ACS patients.

Comparison of the correlation of creatinine- and cystatin C-Based estimated GFR and their differences with new-onset heart failure in a community-based population with type 2 diabetes.

AIMS: This study aimed to investigate the impact of different estimated glomerular filtration rate (eGFR) values like cystatin C-based eGFR (eGFRcys), creatinine-based eGFR (eGFRcr), and their difference (eGFRdiff; eGFRcys -eGFRcr), on the incidence of heart failure (HF) in patients with type 2 diabetes(T2D). METHODS: Being a prospective cohort study, it included 7,967 patients with T2D who underwent serum creatinine and cystatin C tests as part of the Kailuan Group's 6th annual health examination (2016). Subsequently, eGFRcys, eGFRcr, and eGFRdiff were calculated. Patients were categorized into three groups: negative (<-15 mL/min/1.73 m2), midrange (-15 to 15 mL/min/1.73 m2), and positive (> 15 mL/min/1.73 m2) eGFRdiff groups, respectively. Furthermore, the relationship between the various eGFR measurements and new-onset HF were studied using Cox proportional hazards regression, and the potential improvement in predictive capability was evaluated by adding these eGFR metrics to established HF risk models. RESULTS: Among 7967 participants with mean age of 60.51 years, there were 20.92% women and 79.08% men. At baseline, eGFRcys and eGFRcr values differed by more than 15 mL/min/1.73m2 in 41.3% of participants. During a median follow-up period of 3.76 years, there were 172 (2.16%) new HF cases and 517 (6.49%) all-cause deaths. The cumulative incidence of HF in the midrange, negative, and positive eGFRdiff groups was 1.74%, 4.10%, and 0.61%, respectively (p < 0.001). In multivariable adjusted models, participants in the negative eGFRdiff group had higher risk of HF compared with the midrange eGFRdiff group (HR, 2.15; 95% CI, 1.57-2.94). Conversely, participants in the positive eGFRdiff group had lower risk for HF (HR, 0.40; 95% CI, 0.17-0.93). And each 15 mL/min/ 1.73 m2 higher eGFRdiff was associated with 34% (HR, 0.66; 95% CI, 0.58 - 0.47)lower risk of incident HF. The predictive capacity for HF risk in diabetic individuals was enhanced by adding eGFRcys or eGFRdiff to established HF risk models, with eGFRcys showing more significant additional predictive value. CONCLUSION: These findings suggest that large differences between eGFRcys and eGFRcr were common in community-based population with T2D. Different eGFR metrics can independently predict HF incidence in patients with T2D. Additionally, metrics like eGFRcys and eGFRdiff provide significant predictive value for HF risks beyond traditional risk factors, with eGFRcys showing more pronounced benefits in such cases.

Assessment of Plasma Cystatin C as a Marker of Acute Renal Injury in Patients Undergoing Extracorporeal Shock Wave Lithotripsy for Renal Stone Disease.

Introduction This study aimed to assess plasma cystatin C (CysC) as a marker of acute kidney injury (AKI) in patients undergoing extracorporeal shock wave lithotripsy (ESWL). We compared serum levels of CysC, C-reactive protein (CRP), and creatinine before and after ESWL. The study results may have implications for early detection of AKI and prevention of progression to chronic kidney disease. Methodology This prospective observational study included 105 adult participants and was conducted from August 2022 to July 2024. ESWL was the only modality of treatment. Results Forty-eight (46%) patients developed AKI after ESWL. Patients with AKI had significantly higher post-ESWL mean plasma CysC levels than patients without AKI (121 ± 0.25 vs. 0.94 ± 0.22 mg/dL, respectively; P = 0.001). The mean serum CRP levels after ESWL were significantly higher in patients who developed AKI compared with those who did not (4.36 ± 1.63 vs. 2.64 ± 0.95 mg/dL, respectively; P = 0.001). Conclusions In patients with renal stone disease, serum creatinine, serum CRP, and plasma CysC can be used as markers of acute renal injury after ESWL.

Estimated glomerular filtration rate in clinical practice: Consensus positioning of the Brazilian Society of Nephrology (SBN) and Brazilian Society of Clinical Pathology and Laboratory Medicine (SBPC/ML) / Estimativa da taxa de filtração glomerular na prática clínica: posicionamento consensual da Sociedade Brasileira de Nefrologia (SBN) e Sociedade Brasileira de Patologia Clínica e Medicina Laboratorial (SBPC/ML)

ABSTRACT Chronic kidney disease (CKD) represents one of today's main public health problems. Serum creatinine measurement and estimation of the glomerular filtration rate (GFR) are the main tools for evaluating renal function. There are several equations to estimate GFR, and CKD-EPI equation (Chronic Kidney Disease - Epidemiology) is the most recommended one. There are still some controversies regarding serum creatinine measurement and GFR estimation, since several factors can interfere in this process. An important recent change was the removal of the correction for race from the equations for estimating GFR, which overestimated kidney function, and consequently delayed the implementation of treatments such as dialysis and kidney transplantation. In this consensus document from the Brazilian Societies of Nephrology and Clinical Pathology and Laboratory Medicine, the main concepts related to the assessment of renal function are reviewed, as well as possible existing controversies and recommendations for estimating GFR in clinical practice.

RESUMO A doença renal crônica (DRC) representa um dos principais problemas de saúde pública da atualidade. A dosagem da creatinina sérica e a estimativa da taxa de filtração glomerular (TFG) são as principais ferramentas para avaliação da função renal. Para a estimativa da TFG, existem diversas equações, sendo a mais recomendada a CKD-EPI (Chronic Kidney Disease - Epidemiology). Existem ainda algumas controvérsias com relação à dosagem da creatinina sérica e da estimativa da TFG, uma vez que vários fatores podem interferir nesse processo. Uma importante mudança recente foi a retirada da correção por raça das equações para estimativa da TFG, que superestimavam a função renal, e consequentemente retardavam a implementação de tratamentos como diálise e transplante renal. Neste documento de consenso da Sociedade Brasileira de Nefrologia e Sociedade Brasileira de Patologia Clínica e Medicina Laboratorial são revisados os principais conceitos relacionados à avaliação da função renal, possíveis controvérsias existentes e recomendações para a estimativa da TFG na prática clínica.

Associations Between CYP3A5 (c.6986A>G) Gene Polymorphism and Kidney Impairment in Hypertensive Adults Without Cystatin C Elevation.

OBJECTIVE: This study aimed to explore the potential role of CYP3A5 (c. 6986A>G) gene polymorphism in predicting kidney function impairment in patients with hypertension who did not have elevated serum cystatin C. METHODS: We recruited a group of patients with hypertension who did not have elevated cystatin C and analyzed the CYP3A5 (c. 6986A>G) gene polymorphism. Chi-square tests were used to compare the clinical characteristics and genotypic distribution between the two groups. Logistic regression analysis was used to explore the association between CYP3A5 (c.6986A>G) gene polymorphism and renal function impairment in hypertension with non-elevated cystatin. RESULTS: In patients with hypertension who participated in the study, there was a significant association between CYP3A5 (c. 6986A>G) gene polymorphism and kidney function impairment (p < 0.05). Patients with the CYP3A5 (c. 6986A>G) mutation display a greater risk of kidney function impairment. CONCLUSION: CYP3A5 (c. 6986A>G) gene AA homozygote polymorphism significantly increases risk of kidney function impairment in patients with hypertension with normal cystatin C. However, further studies are needed to validate this association and to further understand the mechanism of CYP3A5 (c. 6986A>G) gene polymorphism in kidney function impairment in patients with hypertension.

Sex difference in the association between creatinine-to-cystatin C ratio and metabolic syndrome among Chinese adults.

Background: Metabolic syndrome (MetS), characterized by central obesity, insulin resistance, dyslipidemia, and hypertension, affects 20-25% of the global population. The creatinine-to-cystatin C ratio (CCR) is an indicator of skeletal muscle mass. While CCR may play a role in MetS development, sex differences in these associations are not fully understood. Therefore, this study aimed to investigate how CCR levels are associated with MetS in a Chinese adult population, focusing on possible sex disparities. Method: We conducted a retrospective cross-sectional analysis of 9,376 adults from Xiamen Chang Gung Hospital between 2014 to 2016. We examined the relationship between CCR and MetS, adjusting for cardiometabolic risk factors. Results: The prevalence of MetS was 24.7% in males and 18.0% in females. Interestingly, we observed significant sex differences in the association between CCR quartiles and MetS. Females in the lowest CCR quartile had a significantly higher risk of MetS (odds ratio=1.84). Receiver operating characteristic curve analysis revealed acceptable diagnostic power of CCR for MetS in females (area under the curve=0.65) but not in males. Conclusion: Our findings suggest that CCR is an independent risk factor for MetS in females, highlighting the importance of sex-specific assessments when evaluating MetS risk.

Peripheral dopamine suppression and elevated cystatin C in early diabetic nephropathy in spontaneously diabetic rats.

Intrarenal dopamine plays a protective role against the development of diabetic nephropathy during the early stages of the disease. In streptozotocin-induced diabetic mice with renal-specific catechol-O-methyl transferase knockout, intrarenal dopamine was found to suppress glomerular hyperfiltration, reduce oxidative stress and inflammation, and inhibit fibrosis. However, although dopamine activation in streptozotocin-induced diabetic models has been shown to provide renal protection, the role of dopamine in models of naturally induced diabetes mellitus is still unclear. In the present study, we orally administered 10 mg/kg benserazide, a peripheral decarboxylase inhibitor, to spontaneously diabetic Torii rats daily to investigate the activation of the renal dopaminergic system during the progression of diabetic nephropathy. Our findings show that peripheral dopamine decreased urinary 8-iso-prostaglandin F2α and suppressed increases in plasma cystatin C levels. This study demonstrates that a reduction in peripheral dopamine can exacerbate renal dysfunction, even in the early stages of diabetic nephropathy characterized by glomerular hyperfiltration, thereby clarifying the pivotal role of endogenous peripheral dopamine in modulating oxidative stress and kidney performance.NEW & NOTEWORTHY By administering a peripheral decarboxylase inhibitor, we revealed that peripheral dopamine inhibits both the increase in urinary 8-iso-prostaglandin F2α, an oxidative stress marker, and the increase in plasma cystatin C, an early renal dysfunction marker, even in the early stages of diabetic nephropathy characterized by glomerular hyperfiltration. By visualizing renal dopamine precursor distribution, we highlighted the role of endogenous renal dopamine in oxidative stress and renal function following the onset of glomerular hyperfiltration.