| 1. |
- Rhodin, Malin M., et al.
(författare)
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Human renal function maturation : a quantitative description using weight and postmenstrual age
- 2009
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Ingår i: Pediatric nephrology (Berlin, West). - : Springer Science and Business Media LLC. - 0931-041X .- 1432-198X. ; 24:1, s. 67-76
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Tidskriftsartikel (refereegranskat)abstract
- This study pools published data to describe the increase in glomerular filtration rate (GFR) from very premature neonates to young adults. The data comprises measured GFR (using polyfructose, Cr-51-EDTA, mannitol or iohexol) from eight studies (n=923) and involved very premature neonates (22 weeks postmenstrual age) to adulthood (31 years). A nonlinear mixed effects approach (NONMEM) was used to examine the influences of size and maturation on renal function. Size was the primary covariate, and GFR was standardized for a body weight of 70 kg using an allometric power model. Postmenstrual age (PMA) was a better descriptor of maturational changes than postnatal age (PNA). A sigmoid hyperbolic model described the nonlinear relationship between GFR maturation and PMA. Assuming an allometric coefficient of 3/4, the fully mature (adult) GFR is predicted to be 121.2 mL/min per 70 kg [95% confidence interval (CI) 117-125]. Half of the adult value is reached at 47.7 post-menstrual weeks (95% CI 45.1-50.5), with a Hill coefficient of 3.40 (95% CI 3.03-3.80). At 1-year postnatal age, the GFR is predicted to be 90% of the adult GFR. Glomerular filtration rate can be predicted with a consistent relationship from early prematurity to adulthood. We propose that this offers a clinically useful definition of renal function in children and young adults that is independent of the predictable changes associated with age and size.
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| 2. |
- Inker, Lesley A., et al.
(författare)
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CKD-EPI and EKFC GFR Estimating Equations: Performance and Other Considerations for Selecting Equations for Implementation in Adults
- 2023
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Ingår i: Journal of the American Society of Nephrology. - 1046-6673. ; 34:12, s. 1953-1964
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Tidskriftsartikel (refereegranskat)abstract
- Background: New CKD-EPI and EKFC estimated GFR (eGFR) equations usingcreatinine (eGFRcr), cystatin C (eGFRcys) and both (eGFRcr-cys) have sufficientaccuracy for use in clinical practice. A better understanding of the equations, includingtheir performance in race, sex and age subgroups, is important for selection of eGFRequations for global implementation.Methods: We evaluated performance (bias and P30) of equations and methods usedfor equation development in an independent study population comprising 4050participants pooled from 12 studies. The mean (SD) mGFR was 76.4 (29.6)ml/min/1.73 m2, age 57.0 (17.4) years, with 1557 (38%) women and 579 (14%) Blackparticipants.Results: Coefficients for creatinine, cystatin C, age and sex in the CKD-EPI and EKFCequations are similar. Performance of the eGFRcr-cys equations in the overallpopulation (bias 90%) was better than the eGFRcr oreGFRcys equations, with fewer differences among race, sex and age subgroups.Differences in performance across subgroups reflected differences in diversity ofsource populations and use of variables for race and sex for equation development.Larger differences among eGFRcr equations reflected regional population differencesin non-GFR determinants of creatinine.Conclusion: CKD-EPI and EKFC equations are approaching convergence. It is notpossible to maximize both accuracy and uniformity in selecting one of the currentlyavailable eGFRcr equations for implementation across regions. Decisions shouldconsider methods for equation development in addition to performance. Wider use ofcystatin C with creatinine could maximize both accuracy and uniformity of GFRestimation using currently available equations.
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| 3. |
- Inker, Lesley A., et al.
(författare)
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New creatinine- and cystatin C-based equations to estimate GFR without race
- 2021
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Ingår i: New England Journal of Medicine. - 0028-4793. ; 385:19, s. 1737-1749
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Tidskriftsartikel (refereegranskat)abstract
- Background: Current equations for estimated glomerular filtration rate (eGFR) that use serum creatinine or cystatin C incorporate age, sex, and race to estimate measured GFR. However, race in eGFR equations is a social and not a biologic construct.Methods: We developed new eGFR equations without race using data from two development data sets: 10 studies (8254 participants, 31.5% Black) for serum creatinine and 13 studies (5352 participants, 39.7% Black) for both serum creatinine and cystatin C. In a validation data set of 12 studies (4050 participants, 14.3% Black), we compared the accuracy of new eGFR equations to measured GFR. We projected the prevalence of chronic kidney disease (CKD) and GFR stages in a sample of U.S. adults, using current and new equations.Results: In the validation data set, the current creatinine equation that uses age, sex, and race overestimated measured GFR in Blacks (median, 3.7 ml per minute per 1.73 m2 of body-surface area; 95% confidence interval [CI], 1.8 to 5.4) and to a lesser degree in non-Blacks (median, 0.5 ml per minute per 1.73 m2; 95% CI, 0.0 to 0.9). When the adjustment for Black race was omitted from the current eGFR equation, measured GFR in Blacks was underestimated (median, 7.1 ml per minute per 1.73 m2; 95% CI, 5.9 to 8.8). A new equation using age and sex and omitting race underestimated measured GFR in Blacks (median, 3.6 ml per minute per 1.73 m2; 95% CI, 1.8 to 5.5) and overestimated measured GFR in non-Blacks (median, 3.9 ml per minute per 1.73 m2; 95% CI, 3.4 to 4.4). For all equations, 85% or more of the eGFRs for Blacks and non-Blacks were within 30% of measured GFR. New creatinine-cystatin C equations without race were more accurate than new creatinine equations, with smaller differences between race groups. As compared with the current creatinine equation, the new creatinine equations, but not the new creatinine-cystatin C equations, increased population estimates of CKD prevalence among Blacks and yielded similar or lower prevalence among non-Blacks.Conclusions: New eGFR equations that incorporate creatinine and cystatin C but omit race are more accurate and led to smaller differences between Black participants and non-Black participants than new equations without race with either creatinine or cystatin C alone.
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| 4. |
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| 5. |
- Wang, Yeli, et al.
(författare)
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Discordance Between Creatinine-Based and Cystatin C–Based Estimated GFR : Interpretation According to Performance Compared to Measured GFR
- 2023
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Ingår i: Kidney Medicine. - 2590-0595. ; 5:10
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Tidskriftsartikel (refereegranskat)abstract
- Rationale & Objective: Use of cystatin C in addition to creatinine to estimate glomerular filtration rate (estimated glomerular filtration rate based on cystatin C [eGFRcys] and estimated glomerular filtration rate based on creatinine [eGFRcr], respectively) is increasing. When eGFRcr and eGFRcys are discordant, it is not known which is more accurate, leading to uncertainty in clinical decision making. Study Design: Cross-sectional analysis. Setting & Participants: Four thousand fifty participants with measured glomerular filtration rate (mGFR) from 12 studies in North America and Europe. Exposures: Serum creatinine and serum cystatin C. Outcome(s): Performance of creatinine-based and cystatin C–based glomerular filtration rate estimating equations compared to mGFR. Analytical Approach: We evaluated the accuracy of eGFRcr, eGFRcys, and the combination (eGFRcr-cys) compared to mGFR according to the magnitude of the difference between eGFRcr and eGFRcys (eGFRdiff). We used CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equations to estimate glomerular filtration rate. eGFRdiff was defined as eGFRcys minus eGFRcr and categorized as less than −15, −15 to <15, and ≥15 mL/min/1.73 m2 (negative, concordant, and positive groups, respectively). We compared bias (median of mGFR minus eGFR) and the percentage of eGFR within 30% of mGFR. Results: Thirty percent of participants had discordant eGFRdiff (21.0% and 9.6% negative and positive eGFRdiffs, respectively). In the concordant eGFRdiff group, all equations displayed similar accuracy. In the negative eGFRdiff groups, eGFRcr had a large overestimation of mGFR (−13.4 [−14.5 to −12.2] mL/min/1.73 m2) and eGFRcys had a large underestimation (9.9 [9.1-11.2] mL/min/1.73m2), with opposite results in the positive eGFRdiff group. In both negative and positive eGFRdiff groups, eGFRcr-cys was more accurate than either eGFRcr or eGFRcys. These results were largely consistent across age, sex, race, and body mass index. Limitations: Few participants with major comorbid conditions. Conclusions: Discordant eGFRcr and eGFRcys are common. eGFR using the combination of creatinine and cystatin C provides the most accurate estimates among persons with discordant eGFRcr or eGFRcys.
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| 6. |
- Huh, C, et al.
(författare)
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Decreased metastatic spread in mice homozygous for a null allele of the cystatin C protease inhibitor gene
- 1999
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Ingår i: Molecular Pathology. - 1366-8714. ; 52:6, s. 332-340
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Increased or altered activities of cysteine proteases have been implicated in serious human disorders such as cancer, rheumatoid arthritis, sepsis, and osteoporosis. To improve the current knowledge of the regulatory role of a major mammalian cysteine protease inhibitor, cystatin C, in such disease processes, a cystatin C deficient mouse was generated and characterized. METHODS: The mouse cystatin C gene was inactivated by insertion of a bacterial neo gene through homologous recombination in 129/Sv embryonic stem cells. Embryonic stem cell clones were injected into C57BL/6J blastocysts followed by injection of the blastocysts into pseudopregnant female mice. F1 offspring with agouti coat colour after mating of chimaeric males with C57BL/6J females were examined by DNA analysis, and mice carrying the targeted mutation were intercrossed to obtain homozygous cystatin C deficient (CysC-/-) mice. To study the role of cysteine proteases and their inhibitors in metastasis, the spread of B16-F10 melanoma cells in CysC-/- and wild-type mice was compared. Analysis of the formation of remote metastases was carried out by intravenous injection of beta-galactosidase transfected B16-F10 cells and subsequent determination of cancer cell colonies in the lungs. RESULTS: Cystatin C deficient mice were fertile and showed no gross pathological abnormality up to 6 months of age. Compared with wild-type mice, seven times fewer large metastatic colonies were counted by means of a dissecting microscope in CysC-/- mice two weeks after tail vein injection of B16-F10 cells. At all of eight time points from 15 minutes to two weeks after intravenous injection of tumour cells, the CysC-/- mice had significantly fewer lung metastases. The observed differences were smaller when beta-galactosidase transfected cells were used to allow counting of small colonies. Subcutaneous and intracerebral tumour growth was not different in the CysC-/- mice. CONCLUSIONS: Cystatin C concentrations in vivo might influence metastasis in some tissues. The decreased metastatic spread of B16-F10 cells in CysC-/- mice is the result of both reduced seeding and reduced growth of tumour cells in their lungs.
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| 7. |
- Yu, Weifang, et al.
(författare)
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Cystatin C Deficiency Promotes Epidermal Dysplasia in K14-HPV16 Transgenic Mice
- 2010
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:11
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Tidskriftsartikel (refereegranskat)abstract
- Background: Cysteine protease cathepsins are important in extracellular matrix protein degradation, cell apoptosis, and angiogenesis. Mice lacking cathepsins are protected from tumor progression in several animal models, suggesting that the regulation of cathepsin activities controls the growth of various malignant tumors. Methods and Results: We tested the role of cathepsins using a mouse model of multistage epithelial carcinogenesis, in which the human keratin-14 promoter/enhancer drove the expression of human papillomavirus type 16 (HPV16) early region E6/E7 transgenes. During the progression of premalignant dysplasia, we observed increased expression of cysteine protease cathepsin S, but concomitantly reduced expression of cathepsin endogenous inhibitor cystatin C in the skin tissue extract. Absence of cystatin C in these transgenic mice resulted in more progression of dysplasia to carcinoma in situ on the face, ear, chest, and tail. Chest and ear skin extract real time PCR and immunoblot analysis, mouse serum sample ELISA, tissue immunohistological analysis, and tissue extract-mediated in vitro elastinolysis and collagenolysis assays demonstrated that cystatin C deficiency significantly increased cathepsin expression and activity. In skin from both the chest and ear, we found that the absence of cystatin C reduced epithelial cell apoptosis but increased proliferation. From the same tissue preparations, we detected significantly higher levels of pro-angiogenic laminin 5-derived c2 peptides and concurrently increased neovascularization in cystatin C-deficient mice, compared to those from wild-type control mice. Conclusion: Enhanced cathepsin expression and activity in cystatin C-deficient mice contributed to the progression of dysplasia by altering premalignant tissue epithelial proliferation, apoptosis, and neovascularization.
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