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Pieters TT, Besseling PJ, Bovée DM, Rookmaaker MB, Verhaar MC, Yard B, Hoorn EJ, Joles JA. Discrepancies between transcutaneous and estimated glomerular filtration rates in rats with chronic kidney disease. Kidney Int 2024; 105:1212-1220. [PMID: 38514000 DOI: 10.1016/j.kint.2024.02.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 02/03/2024] [Accepted: 02/12/2024] [Indexed: 03/23/2024]
Abstract
Accurate assessment of the glomerular filtration rate (GFR) is crucial for researching kidney disease in rats. Although validation of methods that assess GFR is crucial, large-scale comparisons between different methods are lacking. Both transcutaneous GFR (tGFR) and a newly developed estimated GFR (eGFR) equation by our group provide a low-invasive approach enabling repeated measurements. The tGFR is a single bolus method using FITC-labeled sinistrin to measure GFR based on half-life of the transcutaneous signal, whilst the eGFR is based on urinary sinistrin clearance. Here, we retrospectively compared tGFR, using both 1- and 3- compartment models (tGFR_1c and tGFR_3c, respectively) to the eGFR in a historic cohort of 43 healthy male rats and 84 male rats with various models of chronic kidney disease. The eGFR was on average considerably lower than tGFR-1c and tGFR-3c (mean differences 855 and 216 μL/min, respectively) and only 20 and 47% of measurements were within 30% of each other, respectively. The relative difference between eGFR and tGFR was highest in rats with the lowest GFR. Possible explanations for the divergence are problems inherent to tGFR, such as technical issues with signal measurement, description of the signal kinetics, and translation of half-life to tGFR, which depends on distribution volume. The unknown impact of isoflurane anesthesia used in determining mGFR remains a limiting factor. Thus, our study shows that there is a severe disagreement between GFR measured by tGFR and eGFR, stressing the need for more rigorous validation of the tGFR and possible adjustments to the underlying technique.
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Affiliation(s)
- Tobias T Pieters
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Paul J Besseling
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dominique M Bovée
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Maarten B Rookmaaker
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marianne C Verhaar
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Benito Yard
- Department of Medicine, University Hospital Mannheim, University of Heidelberg, Mannheim, Germany
| | - Ewout J Hoorn
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jaap A Joles
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands.
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Gritter M, Wei KY, Wouda RD, Musterd-Bhaggoe UM, Dijkstra KL, Kers J, Ramakers C, Vogt L, de Borst MH, Danser AHJ, Hoorn EJ, Rotmans JI. Chronic kidney disease increases the susceptibility to negative effects of low and high potassium intake. Nephrol Dial Transplant 2024; 39:795-807. [PMID: 37813819 PMCID: PMC11045281 DOI: 10.1093/ndt/gfad220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Indexed: 10/11/2023] Open
Abstract
BACKGROUND Dietary potassium (K+) has emerged as a modifiable factor for cardiovascular and kidney health in the general population, but its role in people with chronic kidney disease (CKD) is unclear. Here, we hypothesize that CKD increases the susceptibility to the negative effects of low and high K+ diets. METHODS We compared the effects of low, normal and high KChloride (KCl) diets and a high KCitrate diet for 4 weeks in male rats with normal kidney function and in male rats with CKD using the 5/6th nephrectomy model (5/6Nx). RESULTS Compared with rats with normal kidney function, 5/6Nx rats on the low KCl diet developed more severe extracellular and intracellular K+ depletion and more severe kidney injury, characterized by nephromegaly, infiltration of T cells and macrophages, decreased estimated glomerular filtration rate and increased albuminuria. The high KCl diet caused hyperkalemia, hyperaldosteronism, hyperchloremic metabolic acidosis and severe hypertension in 5/6Nx but not in sham rats. The high KCitrate diet caused hypochloremic metabolic alkalosis but attenuated hypertension despite higher abundance of the phosphorylated sodium chloride cotransporter (pNCC) and similar levels of plasma aldosterone and epithelial sodium channel abundance. All 5/6Nx groups had more collagen deposition than the sham groups and this effect was most pronounced in the high KCitrate group. Plasma aldosterone correlated strongly with kidney collagen deposition. CONCLUSIONS CKD increases the susceptibility to negative effects of low and high K+ diets in male rats, although the injury patterns are different. The low K+ diet caused inflammation, nephromegaly and kidney function decline, whereas the high K+ diet caused hypertension, hyperaldosteronism and kidney fibrosis. High KCitrate attenuated the hypertensive but not the pro-fibrotic effect of high KCl, which may be attributable to K+-induced aldosterone secretion. Our data suggest that especially in people with CKD it is important to identify the optimal threshold of dietary K+ intake.
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Affiliation(s)
- Martin Gritter
- Department of Internel Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Kuang-Yu Wei
- Department of Internel Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Internal Medicine, Division of Nephrology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Rosa D Wouda
- Department of Internal Medicine, Section of Nephrology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Usha M Musterd-Bhaggoe
- Department of Internel Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Kyra L Dijkstra
- Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jesper Kers
- Pathology, Leiden University Medical Center, Leiden, The Netherlands
- Pathology, Amsterdam University Medical Center, Amsterdam, The Netherlands
- Van ‘t Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Liffert Vogt
- Department of Internal Medicine, Section of Nephrology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Martin H de Borst
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Alexander H J Danser
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Ewout J Hoorn
- Department of Internel Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Joris I Rotmans
- Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
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Kim HJ, Jung CY, Kim HW, Park JT, Yoo TH, Kang SW, Park SK, Kim YH, Sung SA, Hyun YY, Oh KH, Han SH. Proteinuria Modifies the Relationship Between Urinary Sodium Excretion and Adverse Kidney Outcomes: Findings From KNOW-CKD. Kidney Int Rep 2023; 8:1022-1033. [PMID: 37180512 PMCID: PMC10166734 DOI: 10.1016/j.ekir.2023.02.1078] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 01/10/2023] [Accepted: 02/13/2023] [Indexed: 02/24/2023] Open
Abstract
Introduction High sodium intake is associated with increased proteinuria. Herein, we investigated whether proteinuria could modify the association between urinary sodium excretion and adverse kidney outcomes in patients with chronic kidney disease (CKD). Methods In this prospective observational cohort study, we included 967 participants with CKD stages G1 to G5 between 2011 and 2016, who measured 24-hour urinary sodium and protein excretion at baseline. The main predictors were urinary sodium and protein excretion levels. The primary outcome was CKD progression, which was defined as a ≥50% decline in the estimated glomerular filtration rate (eGFR) or the onset of kidney replacement therapy. Results During a median follow-up period of 4.1 years, the primary outcome events occurred in 287 participants (29.7%). There was a significant interaction between proteinuria and sodium excretion for the primary outcome (P = 0.006). In patients with proteinuria of <0.5 g/d, sodium excretion was not associated with the primary outcome. However, in patients with proteinuria of ≥0.5 g/d, a 1.0 g/d increase in sodium excretion was associated with a 29% higher risk of adverse kidney outcomes. Moreover, in patients with proteinuria of ≥0.5 g/d, the hazard ratios (HRs) (95% confidence intervals[CIs]) for sodium excretion of <3.4 and ≥3.4 g/d were 2.32 (1.50-3.58) and 5.71 (3.58-9.11), respectively, compared with HRs for patients with proteinuria of <0.5 g/d and sodium excretion of <3.4 g/d. In sensitivity analysis with 2 averaged values of sodium and protein excretion at baseline and third year, the results were similar. Conclusion Higher urinary sodium excretion was more strongly associated with an increased risk of adverse kidney outcomes in patients with higher proteinuria levels.
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Affiliation(s)
- Hyo Jeong Kim
- Department of Internal Medicine, Yonsei University College of Medicine, Institute of Kidney Disease Research, Seoul, Republic of Korea
- Division of Nephrology, Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Chan-Young Jung
- Department of Internal Medicine, Yonsei University College of Medicine, Institute of Kidney Disease Research, Seoul, Republic of Korea
- Division of Nephrology, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Hyung Woo Kim
- Department of Internal Medicine, Yonsei University College of Medicine, Institute of Kidney Disease Research, Seoul, Republic of Korea
| | - Jung Tak Park
- Department of Internal Medicine, Yonsei University College of Medicine, Institute of Kidney Disease Research, Seoul, Republic of Korea
| | - Tae-Hyun Yoo
- Department of Internal Medicine, Yonsei University College of Medicine, Institute of Kidney Disease Research, Seoul, Republic of Korea
| | - Shin-Wook Kang
- Department of Internal Medicine, Yonsei University College of Medicine, Institute of Kidney Disease Research, Seoul, Republic of Korea
| | - Sue K. Park
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
- Cancer Research Institute, Seoul National University, Seoul, Republic of Korea
- Department of Biomedical Science, Seoul National University Graduate School, Seoul, Republic of Korea
| | - Yeong Hoon Kim
- Department of Internal Medicine, Inje University Busan Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Su Ah Sung
- Department of Internal Medicine, Nowon Eulji Medical Center, Eulji University, Seoul, Republic of Korea
| | - Young Youl Hyun
- Department of Internal Medicine, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, Seoul, Korea
| | - Kook-Hwan Oh
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Seung Hyeok Han
- Department of Internal Medicine, Yonsei University College of Medicine, Institute of Kidney Disease Research, Seoul, Republic of Korea
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Maaliki D, Itani MM, Itani HA. Pathophysiology and genetics of salt-sensitive hypertension. Front Physiol 2022; 13:1001434. [PMID: 36176775 PMCID: PMC9513236 DOI: 10.3389/fphys.2022.1001434] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
Most hypertensive cases are primary and heavily associated with modifiable risk factors like salt intake. Evidence suggests that even small reductions in salt consumption reduce blood pressure in all age groups. In that regard, the ACC/AHA described a distinct set of individuals who exhibit salt-sensitivity, regardless of their hypertensive status. Data has shown that salt-sensitivity is an independent risk factor for cardiovascular events and mortality. However, despite extensive research, the pathogenesis of salt-sensitive hypertension is still unclear and tremendously challenged by its multifactorial etiology, complicated genetic influences, and the unavailability of a diagnostic tool. So far, the important roles of the renin-angiotensin-aldosterone system, sympathetic nervous system, and immune system in the pathogenesis of salt-sensitive hypertension have been studied. In the first part of this review, we focus on how the systems mentioned above are aberrantly regulated in salt-sensitive hypertension. We follow this with an emphasis on genetic variants in those systems that are associated with and/or increase predisposition to salt-sensitivity in humans.
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Affiliation(s)
- Dina Maaliki
- Department of Pharmacology and Toxicology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Maha M. Itani
- Department of Pharmacology and Toxicology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Hana A. Itani
- Department of Pharmacology and Toxicology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
- *Correspondence: Hana A. Itani,
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Upregulation of Mineralocorticoid Receptor Contributes to Development of Salt-Sensitive Hypertension after Ischemia-Reperfusion Injury in Rats. Int J Mol Sci 2022; 23:ijms23147831. [PMID: 35887178 PMCID: PMC9324399 DOI: 10.3390/ijms23147831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/08/2022] [Accepted: 07/15/2022] [Indexed: 02/06/2023] Open
Abstract
The ischemia-reperfusion injury (IRI) of rat kidneys is used as a model of acute kidney injury. Salt-sensitive hypertension occurs in rats after IRI, and the distal nephrons play important roles in the development of this condition. We investigated the role of the mineralocorticoid receptor (MR) in the progression of IRI-induced salt-sensitive hypertension in rats. Fourteen days after right-side nephrectomy, IRI was induced by clamping the left renal artery, with sham surgery performed as a control. IRI rats were provided with normal water or water with 1.0% NaCl (IRI/NaCl), or they were implanted with an osmotic mini-pump to infuse vehicle or aldosterone (IRI/Aldo). Esaxerenone, a non-steroidal MR blocker (MRB), was administered to IRI/NaCl and IRI/Aldo rats for 6 weeks. MR expression increased by day 7 post-IRI. Blood pressure and urinary protein excretion increased in IRI/NaCl and IRI/Aldo rats over the 6-week period, but these effects were negated by MRB administration. The MRB attenuated the expression of the gamma-epithelial sodium channel (ENaC) and renal damage. The ENaC inhibitor, amiloride, ameliorated hypertension and renal damage in IRI/NaCl and IRI/Aldo rats. Our findings thus showed that MR upregulation may play a pivotal role in ENaC-mediated sodium uptake in rats after IRI, resulting in the development of salt-sensitive hypertension in response to salt overload or the activation of the renin-angiotensin-aldosterone system.
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Blijdorp CJ, Hartjes TA, Wei K, van Heugten MH, Bovée DM, Budde RP, van de Wetering J, Hoenderop JG, van Royen ME, Zietse R, Severs D, Hoorn EJ. Nephron mass determines the excretion rate of urinary extracellular vesicles. J Extracell Vesicles 2022; 11:e12181. [PMID: 35064766 PMCID: PMC8783354 DOI: 10.1002/jev2.12181] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 11/15/2021] [Accepted: 12/08/2021] [Indexed: 12/20/2022] Open
Abstract
Urinary extracellular vesicles (uEVs) are emerging as non-invasive biomarkers for various kidney diseases, but it is unknown how differences in nephron mass impact uEV excretion. To address this, uEV excretion was measured before and after human kidney donor nephrectomy and rat nephrectomy. In male and female donors, uEVs were quantified in cell-free spot and 24-h urine samples using nanoparticle tracking analysis (NTA), EVQuant, and CD9-time-resolved fluorescence immunoassay. Female donors had significantly lower total kidney volume (TKV) and excreted 49% fewer uEVs than male donors. uEV excretion correlated positively with estimated glomerular filtration rate (eGFR), creatinine clearance, and TKV (R's between 0.6 and 0.7). uEV excretion rate could also be predicted from spot urines after multiplying spot uEV/creatinine by 24-h urine creatinine. Donor nephrectomy reduced eGFR by 36% ± 10%, but the excretion of uEVs by only 16% (CD9+ uEVs -37%, CD9- uEVs no decrease). Donor nephrectomy increased the podocyte marker WT-1 and the proximal tubule markers NHE3, NaPi-IIa, and cubilin in uEVs two- to four-fold when correcting for the nephrectomy. In rats, the changes in GFR and kidney weight correlated with the changes in uEV excretion rate (R = 0.46 and 0.60, P < 0.01). Furthermore, the estimated degree of hypertrophy matched the change in uEV excretion rate (1.4- to 1.5-fold after uninephrectomy and four-fold after 5/6th nephrectomy). Taken together, our data show that uEV excretion depends on nephron mass, and that nephrectomy reduces uEV excretion less than expected based on nephron loss due to compensatory hypertrophy. The major implication of our findings is that a measure for nephron mass or uEV excretion rate should be included when comparing uEV biomarkers between individuals.
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Affiliation(s)
- Charles J. Blijdorp
- Department of Internal Medicine, Division of Nephrology and TransplantationErasmus MC, University Medical Center RotterdamRotterdamThe Netherlands
| | - Thomas A. Hartjes
- Department of PathologyErasmus Medical Center, University Medical Center RotterdamRotterdamThe Netherlands
| | - Kuang‐Yu Wei
- Department of Internal Medicine, Division of Nephrology and TransplantationErasmus MC, University Medical Center RotterdamRotterdamThe Netherlands
| | - Martijn H. van Heugten
- Department of Internal Medicine, Division of Nephrology and TransplantationErasmus MC, University Medical Center RotterdamRotterdamThe Netherlands
| | - Dominique M. Bovée
- Department of Internal Medicine, Division of Nephrology and TransplantationErasmus MC, University Medical Center RotterdamRotterdamThe Netherlands
| | - Ricardo P.J. Budde
- Department of Radiology and Nuclear MedicineErasmus Medical Center, University Medical Center RotterdamRotterdamThe Netherlands
| | - Jacqueline van de Wetering
- Department of Internal Medicine, Division of Nephrology and TransplantationErasmus MC, University Medical Center RotterdamRotterdamThe Netherlands
| | - Joost G.J. Hoenderop
- Department of PhysiologyRadboud University Medical CenterNijmegenThe Netherlands
| | - Martin E. van Royen
- Department of PathologyErasmus Medical Center, University Medical Center RotterdamRotterdamThe Netherlands
| | - Robert Zietse
- Department of Internal Medicine, Division of Nephrology and TransplantationErasmus MC, University Medical Center RotterdamRotterdamThe Netherlands
| | - David Severs
- Department of Internal Medicine, Division of Nephrology and TransplantationErasmus MC, University Medical Center RotterdamRotterdamThe Netherlands
| | - Ewout J. Hoorn
- Department of Internal Medicine, Division of Nephrology and TransplantationErasmus MC, University Medical Center RotterdamRotterdamThe Netherlands
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