• Clinical and Experimental Pediatrics
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• v.48 no.6
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• pp.614-618
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• 2005

Purpose : Cystatin C has been proposed for the assessment of glomerular filtration rate, being more accurate than creatinine determination. We measured serum cystatin C concentrations in the pediatric population, and analysed the correlation between cystatin C and glomerular filtration rate. Methods : Cystatin C and creatinine were measured by the particle enhanced nephelometric immunoassay and Jaffé method, respectively, in 276 children and adolescents without evidence of kidney disease. The glomerular filtration rate was estimated by Schwartz's formula. Results : The mean serum cystatin C concentration was significantly higher in infants under the age of 12 months than in older population. There was a negative correlation between cystatin C and age under 12 months, but not a significant change of cystatin C with age in children older than 12 months. For children older than 12 months, the reference range of cystatin C was 0.46-1.05 mg/L. On the other hand, there was a positive correlation between creatinine and age in the whole population. We also observed a positive correlation between estimated glomerular filtration rate and 1/cystatin C. Conclusion : The measurement of cystatin C is more practical than creatinine for estimating glomerular filtration rate in the pediatric population.

• Childhood Kidney Diseases
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• v.18 no.2
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• pp.85-91
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• 2014

Purpose: We aimed to investigate the correlation between serum cystatin C and clinical manifestations in pediatric patients with urinary tract infections (UTIs). Methods: We studied 137 patients admitted with UTIs from June 2012 to May 2014. Depending on the presence of renal cortical defects on 99m Tc-dimercaptosuccinic acid scintigraphy, we classified patients into non-renal and renal defect groups. Laboratory and clinical parameters were analyzed, including the levels of serum cystatin C. The correlation between cystatin C and other variables was assessed. Results: Serum cystatin C levels did not differ between the non-renal and renal defect groups. In both groups, serum cystatin C levels increased after 4-5 days of treatment, compared with the level at admission (P<0.001). However, mean levels were within normal ranges. The concentration of serum cystatin C positively correlated with serum creatinine and negatively correlated with age (P <0.05). In contrast, there was no correlation between serum cystatin C and other variables. Conclusion: Serum cystatin C does not appear to be a useful biomarker for renal defects in pediatric patients with UTIs. Further studies are necessary to conclude whether serum cystatin C is helpful in predicting deterioration in renal function in pediatric patients with UTIs.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.3
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• pp.203-213
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• 2017

Serum creatinine-based eGFR and serum cystatin C-based eGFR are the most popular methods for measuring renal function. Thyroid hormone is known to affect serum creatinine-based eGFR and serum cystatin C-based eGFR; however, the clinical significance of thyroid dysfunctional patients of renal function evaluation has not been fully elucidated to date. This study examined the effect of thyroid hormone on serum creatinine-based eGFR and serum cystatin C-based eGFR. Moreover, we also evaluated the correlation analysis between serum creatinine-based eGFR and serum cystatin C-based eGFR in patients with thyroid dysfunction. A total of 442 patients with hypothyroidism and 284 patients with hyperthyroidism were investigated. A correlation analysis between thyroid hormone and serum creatinine- (and cystatin C-) based eGFR was performed. A correlation analysis between thyroid hormone and serum cystatin-C based eGFR indicated that serum cystatin-C based eGFR is more of an independent biomarker than serum creatinine-based eGFR in thyroid dysfunction patients. Therefore, serum cystatin C-based eGFR more accurately reflects renal function than serum creatinine-based eGFR in thyroid dysfunction patients.

• Clinical and Experimental Pediatrics
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• v.52 no.9
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• pp.999-1004
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• 2009

Purpose : Glomerular filtration rate (GFR) is a fundamental parameter in assessing renal function and predicting the progression of chronic renal disease. Because the use of serum creatinine has several disadvantages, many studies have investigated the use of cystatin C for estimating GFR. We compared creatinine clearance and GFR with formulas using serum creatinine and cystatin C. Methods : We retrospectively analyzed 211 patients with various renal diseases and classified them into two groups according to creatinine clearance (Group 1: CrCl >$90mL/min/1.73m^2$, Group 2: CrCl <$90mL/min/1.73m^2$). We measured serum creatinine, cystatin C, and creatinine clearance. We calculated GFR using the Schwartz, Counahan, Filler and Lepage, Bokencamp et al, and Grubb et al formulas. Results : GFR determined by the Schwartz formula had the highest correlation to creatinine clearance (r=0.415, P=0.00). GFR determined by various formulas using cystatin C had lower correlation to creatinine clearance (r=0.187, r=0.187, r=0.291). The Schwartz and Counahan formulas showed greater diagnostic accuracy in detecting decreased GFR than cystatin C in group 2 (areas under the curve: Schwartz, 0.596; Counahan, 0.572; Filler, 0.512; Bokencamp, 0.508; and Grubb, 0.514). Conclusion : GFR determined by the Schwartz and Counahan formulas using serum creatinine showed higher correlation coefficient than that determined by formulas using cystatin C. The formulas using cystatin C were not superior to those using serum creatinine in detecting decreased GFR. Cystatin C measurement was not satisfactory for assessing GFR in patients whose renal function was not severely decreased.

• Korean Journal of Veterinary Service
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• v.46 no.3
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• pp.181-192
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• 2023

Cystatin C, a low-molecular-weight protein synthesized by cells, is being explored as a valuable biomarker for assessing renal function in veterinary medicine. Although the relationship between cystatin C and heart disease remains unclear, some studies suggest a possible association. This retrospective case-control study aimed to investigate the role of cystatin C as a biomarker for heart disease and its correlation with diuretic use in veterinary clinical practice. A total of 39 dogs were included in this study, comprising 9 control dogs without a predisposition to heart disease and 30 dogs in the study group diagnosed with heart disease. Among the 30 dogs with heart disease, 18 exhibited symptoms indicative of heart failure. Results showed significantly higher cystatin C levels in the heart disease group compared to the control group (P<0.05). However, no significant differences were observed among different stages of heart disease severity in the control group. Furthermore, cystatin-C showed statistically positive correlations with BUN (r=0.478, P<0.01), creatinine (r=0.506, P<0.01), and furosemide (r=0.338, P<0.05). Diuretics are essential for managing congestive heart failure, and the observed associations between cystatin C and furosemide suggest potential impacts of diuretic use on renal function in dogs with heart failure. Monitoring renal function markers, such as cystatin C, can aid in predicting and managing potential renal complications, ultimately improving the overall health and quality of life of dogs with heart disease.

• Development and Reproduction
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• v.10 no.4
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• pp.263-269
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• 2006

To evaluate the potentiality of industrial use of cysteine proteinase inhibitor (cystatin) of tilapia egg and serum stability of the tilapia cystatin on low temperature storage and heat treatment was studied. When the eggs were stored at $4^{\circ}C$ for 3 days the cystatin activity was not changed much, while the supernatant of egg homogenate lost its cystatin activity significantly, remaining only about 65% of initial activity. When the eggs and serum were subjected to repeated freeze at $-20^{\circ}C$ and thaw at room temperature once a day, the egg cystatin was decreased after 5 cycles of freeze and thaw. However the serum cystatin was not changed by the 5 times repetition of freeze and thaw. More than 80% of egg cystatin activity was remained when the egg was heated at $35^{\circ}C$ for 30 min, but less than 10% was remained when heated at $50^{\circ}C$. On the other hand, the serum cystatin was very resistant to heat, remaining about 74% after heating at as high as $80^{\circ}C$ for 30 min. In summary, the egg cystatin was more stable when stored as intact form of egg rather than as supernatant of homogenate when stored at refrigeration. Egg cystatin was relatively stable against repeated freeze-thaw, and serum was found to be more stable in cysteine proteinase inhibitory activity than egg. Egg cystatin was not very resistant to heat treatment, while serum cystatin was quite resistant to high temperature heat treatment. These results suggest that tilapia egg and serum, especially the serum, would be a useful source for cysteine proteinase inhibitor in surimi production.

• Interdisciplinary Bio Central
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• v.4 no.2
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• pp.4.1-4.4
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• 2012

Background: Serum concentration of cystatin C, a marker of glomerular filtration has been associated with cardiovascular disease (CVD). The aim of this study was to evaluate cystatin C as a marker of obese patients without chronic kidney disease (CKD). Materials and Methods: The study population consisted of 36 subjects with metabolic syndrome and 32 subjects free of metabolic syndrome (the control group). HDL-C, LDL-C, blood urea, triglycerides, glucose, HbA1c, serum cystatin C and serum creatinine were measured in both groups. GFR was calculated in both groups using Cockroft-Gault equation. Results: Obese patients showed higher cystatin C levels than normal samples ($1.28{\pm}0.29$, P < 0.05). In the binary logistic regression, obese patients were significantly associated with elevated cystatin C levels. Conclusion: Our results suggest that cystatin C may be a marker for obese patients and may identify a certain degree of renal dysfunction even when serum creatinine does not exceed the normal level. In this study, we demonstrated that serum creatinineand GFR did not differ significantly between the diabetic and the control groups. Serum concentration of cystatin C was significantly higher in the diabetic group compared with the control group. The strengths of this study are the evaluation of reliability and sensivity in comparison with a 'routine test of GFR'. The methodology used allows an appropriate statistical comparison of reliability in contrast to most other previous evaluations of GFR.

• Childhood Kidney Diseases
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• v.11 no.2
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• pp.161-167
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• 2007

Purpose : GFR(glomerular filtration rate) is a fundamental parameter in detecting renal impairment and predicts the progression of renal disease. Because serum creatinine has several disadvantages, serum cystatin C has been recently proposed as a new endogenous marker for GFR. We compared serum cystatin C with creatinine and creatinine clearance to investigate the clinical usefulness of cystatin C. Methods : We retrospectively analyzed 46 patients(60 case numbers) who had various renal diseases and classified them into 3 groups according to creatinine clearance(Group 1 : CrCl <40 mL/min/$1.73m^2$, Group 2 : CrCl 40-60 mL/min/$1.73m^2$, Group 3 CrCl >60 mL/min/$1.73m^2$). We measured serum creatinine, cystatin C and creatinine clearance and also analyzed the correlations among them. Results : Serum cystatin C and creatinine showed a similar correlation to creatinine clearance (r=0.685, r=0.640, respectively) and showed similar diagnostic accuracy in detecting decreased GFR(AUC, cystatin C 0.829 vs. creatinine 0.826, P=0.848). Serum cystatin C showed a greater sensitivity for detecting a decreased GFR than creatinine in Group 2 and 3(Group 1 : 100% vs. 100%, Group 2 : 70% vs. 35%, Group 3 : 46% vs. 15%). Conclusions : Serum cystatin C could be a useful endogenous marker for GFR and would be superior to serum creatinine in early detection of renal impairment in pediatric patients with renal diseases.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.21
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• pp.9511-9515
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• 2014

Cholangiocarcinoma (CCA) is a cancer of the bile duct epithelial cells. The highest incidence rate of CCA with a poor prognosis and poor response to chemotherapy is found in Southeast Asian countries, especially in northeastern Thailand and Lao PDR. Cathepsin B is a lysosomal cysteine protease which is regulated by cysteine proteinase inhibitors such as cystatin C. Elevation of cathepsin B levels in biological fluid has been observed in patients with inflammatory diseases and many cancers. We aimed to investigate the serum cathepsin B and cystatin C levels of CCA patients to evaluate the feasibility of using cathepsin B and cystatin C as markers for the diagnosis of CCA. Fifty-six sera from CCA patients, 17 with benign biliary diseases (BBD) and 13 from controls were collected and the cathepsin B and cystatin C levels were determined. In addition, cathepsin B expression was investigated immunohistochemically for 9 matched-pairs of cancerous and adjacent tissues of CCA patients. Serum cathepsin B, but not cystatin C, was significantly higher in CCA and BBD patient groups compared to that in the control group. Consistently, all cancerous tissues strongly expressed cathepsin B while adjacent tissues were negative in 7 out of 9 cases. In contrast, serum cystatin C levels were comparable between CCA and control groups, although serum cystatin C levels in the BBD group was higher than that in the control or CCA groups. When the serum cathepsin B to cystatin C ratio was calculated, that of the CCA group was significantly higher than that of the control group, and, although statistically not significant, the ratio of CCA group showed a trend to be higher than that of the BBD group. Thus, the cathepsin B to cystatin C ratio might be used as an alternative marker for aiding diagnosis of CCA.

• Journal of Veterinary Clinics
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• v.33 no.2
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• pp.81-86
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• 2016

Cystatin C is a low molecular weight 13 kilodalton protein. It is known to be a more sensitive marker of glomerular filtration rate than creatinine in humans. The purpose of the present study was to demonstrate the changes of renal markers including cystatin C according to the severity of chronic mitral valve insufficiency (CMVI) and to investigate the clinical relevance of cystatin C as an early renal marker in dogs with CMVI. A retrospective study was performed to assess renal function according to International Small Animal Cardiac Health Council (ISACHC) system classification of heart failure in dogs with CMVI. Thirty seven dogs were divided into a group 1 (healthy dogs ; n = 10), a group 2 (ISACHC I ; n = 10) and a group 3 (ISACHC II-III ; n = 17). In all dogs, serum concentrations of bun (sUr), creatinine (sCr) and cystatin C (sCys-C) were measured with an automated analyzer. In dogs with CMVI, sCys-C concentrations were significantly correlated with sCr concentrations and were independent of age, BW, SBP, and sex. Renal dysfunction tended to occur more frequently as the severity of CMVI increases. In dogs with mild CMVI, only sCys-C concentrations were statistically higher than in healthy dogs. This study demonstrates the clinical relevance of sCys-C. sCys-C may be a valuable renal marker for early diagnosis of renal dysfunction in dogs with CMVI.