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Bovée DM, Cuevas CA, Zietse R, Danser AHJ, Mirabito Colafella KM, Hoorn EJ. Salt-sensitive hypertension in chronic kidney disease: distal tubular mechanisms. Am J Physiol Renal Physiol 2020; 319:F729-F745. [DOI: 10.1152/ajprenal.00407.2020] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Chronic kidney disease (CKD) causes salt-sensitive hypertension that is often resistant to treatment and contributes to the progression of kidney injury and cardiovascular disease. A better understanding of the mechanisms contributing to salt-sensitive hypertension in CKD is essential to improve these outcomes. This review critically explores these mechanisms by focusing on how CKD affects distal nephron Na+ reabsorption. CKD causes glomerulotubular imbalance with reduced proximal Na+ reabsorption and increased distal Na+ delivery and reabsorption. Aldosterone secretion further contributes to distal Na+ reabsorption in CKD and is not only mediated by renin and K+ but also by metabolic acidosis, endothelin-1, and vasopressin. CKD also activates the intrarenal renin-angiotensin system, generating intratubular angiotensin II to promote distal Na+ reabsorption. High dietary Na+ intake in CKD contributes to Na+ retention by aldosterone-independent activation of the mineralocorticoid receptor mediated through Rac1. High dietary Na+ also produces an inflammatory response mediated by T helper 17 cells and cytokines increasing distal Na+ transport. CKD is often accompanied by proteinuria, which contains plasmin capable of activating the epithelial Na+ channel. Thus, CKD causes both local and systemic changes that together promote distal nephron Na+ reabsorption and salt-sensitive hypertension. Future studies should address remaining knowledge gaps, including the relative contribution of each mechanism, the influence of sex, differences between stages and etiologies of CKD, and the clinical relevance of experimentally identified mechanisms. Several pathways offer opportunities for intervention, including with dietary Na+ reduction, distal diuretics, renin-angiotensin system inhibitors, mineralocorticoid receptor antagonists, and K+ or H+ binders.
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Affiliation(s)
- Dominique M. Bovée
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
- Division of Vascular Medicine, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Catharina A. Cuevas
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Robert Zietse
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - A. H. Jan Danser
- Division of Vascular Medicine, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Katrina M. Mirabito Colafella
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
- Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Ewout J. Hoorn
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
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Olukiran OS, Akomolafe RO, Ilesanmi OS, Imafidon CE, Alabi QK. Age-related changes in urinary protein excretion in relation to indices of renal function in Wistar rats. Animal Model Exp Med 2018; 1:295-304. [PMID: 30891579 PMCID: PMC6388057 DOI: 10.1002/ame2.12035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 08/27/2018] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The study determined the fractions of proteins in the urine and plasma of rats at different ages, measured the plasma and urine concentrations of markers of renal function, with a view to determining the influence of proteinuria on renal function. METHODS Eighty Wistar rats were used for this study. Groups 1 and 2 each consisted of eight 1-month-old male and female rats; 3 and 4 had eight 3-month-old male and female rats; 5 and 6 had eight 6-month-old male and female rats; 7 and 8 had eight 9-month old male and female rats; and 9 and 10 had eight 12-month-old male and female rats. RESULTS A fraction of the molecular weight of protein in the urine of rats aged 1, 9 and 12 months was higher than that of 3 and 6 months. The total protein concentration in the urine of male and female rats aged 9 and 12 months was significantly higher than that of rats aged 1 and 3 months. The urine creatinine concentrations of male and female rats aged 9 months were significantly higher when compared with that of 1, 3, 6 and 12 months. CONCLUSION Our results suggest that the 3-month-old rats seem less affected by proteinuria, because they had the least urine protein, and consistent and reduced plasma and urine concentrations of markers of renal function. The results of this study may provide a foundation for future mechanistic inquiries as to why this age group was the least affected by proteinuria.
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Affiliation(s)
- Olaoluwa Sesan Olukiran
- Department of Physiological SciencesFaculty of Basic Medical SciencesObafemi Awolowo UniversityIle‐IfeNigeria
| | - Rufus Ojo Akomolafe
- Department of Physiological SciencesFaculty of Basic Medical SciencesObafemi Awolowo UniversityIle‐IfeNigeria
| | - Olutosin Samuel Ilesanmi
- Department of Biochemistry and Molecular BiologyFaculty of SciencesObafemi Awolowo UniversityIle‐IfeNigeria
| | - Christian Eseigbe Imafidon
- Department of Physiological SciencesFaculty of Basic Medical SciencesObafemi Awolowo UniversityIle‐IfeNigeria
- Department of PhysiologyFaculty of Basic Medical and Health SciencesBowen UniversityIwoNigeria
| | - Quadri Kunle Alabi
- Department of Physiological SciencesFaculty of Basic Medical SciencesObafemi Awolowo UniversityIle‐IfeNigeria
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Cawthorne C, Prenant C, Smigova A, Julyan P, Maroy R, Herholz K, Rothwell N, Boutin H. Biodistribution, pharmacokinetics and metabolism of interleukin-1 receptor antagonist (IL-1RA) using [¹⁸F]-IL1RA and PET imaging in rats. Br J Pharmacol 2011; 162:659-72. [PMID: 20942812 DOI: 10.1111/j.1476-5381.2010.01068.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND AND PURPOSE Positron emission tomography (PET) has the potential to improve our understanding of the preclinical pharmacokinetics and metabolism of therapeutic agents, and is easily translated to clinical studies in humans. However, studies involving proteins radiolabelled with clinically relevant PET isotopes are currently limited. Here we illustrate the potential of PET imaging in a preclinical study of the biodistribution and metabolism of ¹⁸F-labelled IL-1 receptor antagonist ([¹⁸F]IL-1RA) using a novel [¹⁸F]-radiolabelling technique. EXPERIMENTAL APPROACH IL-1RA was radiolabelled by reductive amination on lysine moieties with [¹⁸F]fluoroacetaldehyde. Sprague-Dawley rats were injected intravenously with [¹⁸F]IL-1RA and imaged with a PET camera for 2 h. For the study of IL-1RA metabolites by ex vivoγ-counting of samples, rats were killed 20 min, 1 h or 2 h after injection of [¹⁸F]IL-1RA. KEY RESULTS [¹⁸F]IL-1RA distribution into the major organs of interest was as follows: kidneys >> liver > lungs >> brain. In lungs and liver, [¹⁸F]IL-1RA uptake peaked within 1 min post-injection then decreased rapidly to reach a plateau from 10 min post-injection. In the brain, the uptake exhibited slower pharmacokinetics with a smaller post-injection peak and a plateau from 6 min onward. IL-1RA was rapidly metabolized and these metabolites represented ∼40% of total activity in plasma and ∼80% in urine, 20 min after injection. CONCLUSIONS AND IMPLICATIONS Preclinical PET imaging is a feasible method of assessing the biodistribution of new biological compounds of therapeutic interest rapidly. The biodistribution of [¹⁸F]IL-1RA reported here is in agreement with an earlier study suggesting low uptake in the normal brain, with rapid metabolism and excretion via the kidneys.
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Affiliation(s)
- C Cawthorne
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK
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Yazzie D, Adoga GI, Okolo A, Szlachetka R, Fry D, Glew RH. Decreased urinary excretion of beta-glucuronidase in sickle cell anemia in Nigeria. Ren Fail 1995; 17:57-64. [PMID: 7770645 DOI: 10.3109/08860229509036376] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The activities of five lysosomal hydrolases--namely beta-glucuronidase, beta-hexosaminidase, beta-galactosidase, alpha-galactosidase, and alpha-mannosidase--were measured in the plasma and urine of children (ages, 7 to 15 years) with sickle cell anemia (n = 11) and controls (n = 11) from Jos, Nigeria. The presence of SS hemoglobin was confirmed by electrophoresis of red cell hemolysates. Albuminuria was absent in all of the patients with sickle cell anemia. The creatinine-indexed urinary activity level (units of enzyme activity/milligrams creatinine) and the fractional enzyme excretion (FEE) value, which is defined as the ratio of enzyme clearance to creatinine clearance, were determined for each of the five lysosomal enzymes and compared between the two groups. The mean FEE values for beta-glucuronidase and alpha-galactosidase in the sickle cell patients were 10- and 3.5-fold lower, respectively, than the corresponding control values, and these differences were statistically significant (p < .03) for both enzymes; however, beta-hexosaminidase, beta-galactosidase, and alpha-mannosidase levels in urine were not different between the two groups. When indexed to creatinine, a comparison of the urinary enzyme levels of control and sickle cell patients showed significant differences for beta-glucuronidase (p < .01) and alpha-galactosidase (p < .05) but not for the other three enzymes. Differences in level of plasma enzyme activity between control and sickle cell patients were not significant, except for alpha-galactosidase (p < .05), which was increased slightly (25%) in the sickle cell group. These data indicate that there may be abnormalities in the metabolism of lysosomal enzymes in the kidneys of patients with sickle cell anemia.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D Yazzie
- Department of Biochemistry, School of Medicine, University of New Mexico, Albuquerque 87131, USA
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Poortmans JR, Rampaer L, Wolfs JC. Renal protein excretion after exercise in man. EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY 1989; 58:476-80. [PMID: 2759073 DOI: 10.1007/bf02330700] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Thirteen men were submitted to graded exhaustive cycle exercise to determine the kinetics of proteinuria in the recovery period. Venous blood samples were analysed for haematocrit, lactate, creatinine, total protein and albumin for 1 h following exercise. Urine samples were collected during a 3-h recovery period. Total protein, albumin, and creatinine levels were determined for these samples. Total protein and albumin urinary excretion increased to 581 and 315 micrograms min-1, respectively, at the end of the 1st h of recovery as compared to 42 and 15 micrograms.min-1 for resting values. Plasma volume returned to pre-exercise levels between 30 and 60 min after cessation of exercise, while urinary total protein and albumin content still remained above the resting values for the following 2 h. Both post-exercise urinary total protein and albumin excretion followed a logarithmic decline with the same half-life of 54 min, thus requiring about 4 h to regain resting values. The reduction of plasma volume and the degree of dehydration do not seem to be involved in the process. The present study indicates the delayed recovery of protein handling by the kidney, as compared with other biochemical parameters, and provides accurate information on the kinetics of post-exercise proteinuria.
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Affiliation(s)
- J R Poortmans
- Chimie Physiologique, Institut Supérieur d'Education Physique et de Kinésithérapie, Université Libre de Bruxelles, Belgium
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Christensen CK, Schmitz O, Pedersen EB, Alberti KG, Mogensen CE. Effect of 3-hydroxybutyrate infusion on urinary protein excretion in healthy man. Scand J Clin Lab Invest 1986; 46:239-43. [PMID: 3520791 DOI: 10.3109/00365518609083665] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Diabetic ketoacidosis is often associated with a temporary increase in protein excretion, but the mechanisms are not completely known. The aim of the present study was to examine the effect of acute experimental moderate ketosis on kidney function and specifically on protein handling using an infusion of 3-hydroxybutyrate in healthy subjects. Seven young healthy males were infused with sodium 3-hydroxybutyrate, the peak blood level attained being 1.96 +/- 0.53 mmol/l (SD). The pH in blood and urine rose significantly from 7.40 +/- 0.03 to 7.45 +/- 0.05 (2p less than 0.01) and from 7.29 +/- 0.79 to 8.51 +/- 0.82 (2p less than 0.01), respectively. Urinary beta-2-microglobulin excretion rose significantly from 0.038 microgram/min x/ divided by 1.9 to 0.082 microgram/min x/ divided by 1.4 (geometric mean x/ divided by tolerance factor) (2p less than 0.01) but urinary albumin excretion was unchanged. No changes were seen in blood pressure, glomerular filtration rate and renal plasma flow. A marked reduction in urine flow from 15 to 5 ml/min was noted, but could not be attributed to changes in plasma arginine-vasopressin, which was reduced before and during infusion due to considerable oral water loading. It is concluded that moderate elevation in blood ketone body levels does not induce albuminuria. It is suggested that the temporary proteinuria present in diabetic ketoacidosis may be related to acidosis per se.
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Nath KA, Hostetter MK, Hostetter TH. Pathophysiology of chronic tubulo-interstitial disease in rats. Interactions of dietary acid load, ammonia, and complement component C3. J Clin Invest 1985; 76:667-75. [PMID: 2993363 PMCID: PMC423874 DOI: 10.1172/jci112020] [Citation(s) in RCA: 342] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The human end-stage kidney and its experimental analogue, the remnant kidney in the rat, exhibit widespread tubulo-interstitial disease. We investigated whether the pathogenesis of such tubulo-interstitial injury is dependent upon adaptive changes in tubular function and, in particular, in ammonia production when renal mass is reduced. Dietary acid load was reduced in 1 3/4-nephrectomized rats by dietary supplementation with sodium bicarbonate (NaHCO3), while control rats, paired for serum creatinine after 1 3/4 nephrectomy, were supplemented with equimolar sodium chloride. After 4-6 wk, NaHCO3-supplemented rats demonstrated less impairment of tubular function as measured by urinary excretory rates for total protein and low molecular weight protein and higher transport maximum for para-aminohippurate per unit glomerular filtration rate, less histologic evidence of tubulo-interstitial damage, less deposition of complement components C3 and C5b-9, and a lower renal vein total ammonia concentration. Such differences in tubular function could not be accounted for simply on the basis of systemic alkalinization, and differences in tubular injury could not be ascribed to differences in glomerular function. Because nitrogen nucleophiles such as ammonia react with C3 to form a convertase for the alternative complement pathway, and because increased tissue levels of ammonia are associated with increased tubulo-interstitial injury, we propose that augmented intrarenal levels of ammonia are injurious because of activation of the alternative complement pathway. Chemotactic and cytolytic complement components are thereby generated, leading to tubulo-interstitial inflammation. Thus, alkali supplementation reduces chronic tubulo-interstitial disease in the remnant kidney of the rat, and we propose that this results, at least in part, from reduction in cortical ammonia and its interaction with the alternative complement pathway.
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Maiorca R, Scarpioni L, Cambi V, Carrara GC, Dall'Aglio P. Urinary protein clearances in chronic renal diseases with and without uremia. Clin Chim Acta 1967; 16:253-7. [PMID: 4166398 DOI: 10.1016/0009-8981(67)90189-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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