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Brinker EJ, Hardcastle MR, Dittmer KE, Graff EC. Endocrine fibroblast growth factors in domestic animals. Domest Anim Endocrinol 2024; 89:106872. [PMID: 39059301 DOI: 10.1016/j.domaniend.2024.106872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 06/28/2024] [Accepted: 07/09/2024] [Indexed: 07/28/2024]
Abstract
Fibroblast growth factors (FGFs) are a group of structurally homologous yet functionally pleiotropic proteins. Canonical and intracellular FGFs have primarily autocrine or paracrine effects. However, the FGF19 subfamily, composed of FGF15/19, FGF21, and FGF23, act as endocrine hormones that regulate bile acid, metabolic, and phosphorus homeostasis, respectively. Current research in human and rodent models demonstrates the potential of these endocrine FGFs to target various diseases, including disorders of inherited hypophosphatemia, chronic liver disease, obesity, and insulin resistance. Many diseases targeted for therapeutic use in humans have pathophysiological overlaps in domestic animals. Despite the potential clinical and economic impact, little is known about endocrine FGFs and their signaling pathways in major domestic animal species compared with humans and laboratory animals. This review aims to describe the physiology of these endocrine FGFs, discuss their current therapeutic use, and summarize the contemporary literature regarding endocrine FGFs in domestic animals, focusing on potential future directions.
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Affiliation(s)
- Emily J Brinker
- Department of Pathobiology, College of Veterinary Medicine, 166 Greene Hall, Auburn University, AL, USA 36849; Department of Comparative Pathobiology, Cummings School of Veterinary Medicine at Tufts University, 200 Westboro Road, North Grafton, MA, USA 01536
| | - Michael R Hardcastle
- IDEXX Laboratories Pty. Ltd., 20A Maui Street, Pukete, Hamilton 3200, New Zealand
| | - Keren E Dittmer
- School of Veterinary Sciences, Massey University, Private Bag 11-222, Palmerston North 4442, New Zealand
| | - Emily C Graff
- Department of Pathobiology, College of Veterinary Medicine, 166 Greene Hall, Auburn University, AL, USA 36849; Scott-Ritchey Research Center, College of Veterinary Medicine, Dr. Auburn University, 1265 HC Morgan, AL, USA 36849.
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2
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Tang P, van den Broek DHN, Jepson RE, Geddes RF, Chang Y, Lötter N, Moniot D, Biourge V, Elliott J. Dietary magnesium supplementation in cats with chronic kidney disease: A prospective double-blind randomized controlled trial. J Vet Intern Med 2024; 38:2180-2195. [PMID: 38952053 PMCID: PMC11256178 DOI: 10.1111/jvim.17134] [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: 04/07/2024] [Accepted: 05/31/2024] [Indexed: 07/03/2024] Open
Abstract
BACKGROUND Plasma total magnesium concentration (tMg) is a prognostic indicator in cats with chronic kidney disease (CKD), shorter survival time being associated with hypomagnesemia. Whether this risk factor is modifiable with dietary magnesium supplementation remains unexplored. OBJECTIVES Evaluate effects of a magnesium-enriched phosphate-restricted diet (PRD) on CKD-mineral bone disorder (CKD-MBD) variables. ANIMALS Sixty euthyroid client-owned cats with azotemic CKD, with 27 and 33 allocated to magnesium-enriched PRD or control PRD, respectively. METHODS Prospective double-blind, parallel-group randomized trial. Cats with CKD, stabilized on a PRD, without hypermagnesemia (tMg >2.43 mg/dL) or hypercalcemia (plasma ionized calcium concentration, (iCa) >6 mg/dL), were recruited. Both intention-to-treat and per-protocol (eating ≥50% of study diet) analyses were performed; effects of dietary magnesium supplementation on clinicopathological variables were evaluated using linear mixed effects models. RESULTS In the per-protocol analysis, tMg increased in cats consuming a magnesium-enriched PRD (β, 0.25 ± .07 mg/dL/month; P < .001). Five magnesium supplemented cats had tMg >2.92 mg/dL, but none experienced adverse effects. Rate of change in iCa differed between groups (P = .01), with decreasing and increasing trends observed in cats fed magnesium-enriched PRD and control PRD, respectively. Four control cats developed ionized hypercalcemia versus none in the magnesium supplemented group. Log-transformed plasma fibroblast growth factor-23 concentration (FGF23) increased significantly in controls (β, 0.14 ± .05 pg/mL/month; P = .01), but remained stable in the magnesium supplemented group (β, 0.05±.06 pg/mL/month; P =.37). CONCLUSIONS AND CLINICAL IMPORTANCE Magnesium-enriched PRD is a novel therapeutic strategy for managing feline CKD-MBD in cats, further stabilizing plasma FGF23 and preventing hypercalcemia.
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Affiliation(s)
- Pak‐Kan Tang
- Department of Comparative Biomedical Sciences, Royal Veterinary CollegeUniversity of LondonLondonUnited Kingdom
| | | | - Rosanne E. Jepson
- Department of Clinical Science and Services, Royal Veterinary CollegeUniversity of LondonLondonUnited Kingdom
| | - Rebecca F. Geddes
- Department of Clinical Science and Services, Royal Veterinary CollegeUniversity of LondonLondonUnited Kingdom
| | - Yu‐Mei Chang
- Research Support Office, Royal Veterinary CollegeUniversity of LondonLondonUnited Kingdom
- Present address:
Department of Comparative Biomedical SciencesRoyal Veterinary College, University of LondonLondonUnited Kingdom
| | - Nicola Lötter
- Department of Comparative Biomedical Sciences, Royal Veterinary CollegeUniversity of LondonLondonUnited Kingdom
| | | | | | - Jonathan Elliott
- Department of Comparative Biomedical Sciences, Royal Veterinary CollegeUniversity of LondonLondonUnited Kingdom
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Summers S, Michael HT, Szlosek D, Mack R. Blood fibroblast growth factor 23 concentration in cats with and without chronic kidney disease: a scoping review. J Feline Med Surg 2024; 26:1098612X241234984. [PMID: 38682929 PMCID: PMC11103316 DOI: 10.1177/1098612x241234984] [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] [Indexed: 05/01/2024]
Abstract
OBJECTIVES This study undertook a scoping review of research on blood fibroblast growth factor 23 (FGF-23) concentrations in healthy non-azotemic cats and cats with chronic kidney disease (CKD) to describe the volume and nature of existing literature, to determine whether published studies provide adequate evidence to support the use of FGF-23 as a biomarker in clinical practice and to identify any existing gaps in knowledge. METHODS PRISMA Extension for Scoping Reviews guidelines were used to design and perform the scoping review. Online databases were used to identify observational and clinical studies of blood FGF-23 concentrations in healthy cats and cats with CKD published before December 2022. Study and population characteristics and descriptive data on FGF-23 concentrations were extracted. RESULTS A total of 205 publications were reviewed; 17 were retained for inclusion. Most studies were retrospective. Most studies included cats with International Renal Interest Society stage 2-4 CKD, with some variation. Key concepts explored in the literature include FGF-23 concentrations by CKD stage, effect of dietary phosphate restriction on FGF-23 concentrations, relationship between FGF-23 concentrations and blood phosphorus, calcium and magnesium concentrations, and FGF-23 concentrations in cats with progressive CKD. FGF-23 concentrations tended to be higher in cats with CKD compared with healthy cats, with an overlap between healthy and CKD populations, and there was significant variation within stages of CKD. CONCLUSIONS AND RELEVANCE FGF-23 is a biomarker of interest for the management and monitoring of phosphate overload in cats. Studies support several potential clinical applications for measuring FGF-23 concentration in practice; however, evidence is limited. Research on FGF-23 in cats with CKD would benefit from longitudinal, prospective studies that standardize CKD diagnosis and categorize cats by stage using current guidelines. Studies should include cats with early-stage, non-azotemic CKD and use commercially available assays so such results are comparable across studies.
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Affiliation(s)
- Stacie Summers
- Department of Clinical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, USA
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Lapsina S, Nagler N, Müller SF, Holtdirk A, Kottmann T, Müller E, Schäfer I. Fibroblast Growth Factor-23 (FGF-23) in Dogs-Reference Interval and Correlation with Hematological and Biochemical Parameters. Animals (Basel) 2023; 13:3202. [PMID: 37893926 PMCID: PMC10603748 DOI: 10.3390/ani13203202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 09/25/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023] Open
Abstract
Fibroblast growth factor-23 (FGF-23) is a phosphaturic hormone used to monitor chronic kidney disease (CKD) in humans. The aims of this study were (1) to determine the intra- and interassay precision of the FGF-23 concentrations in dogs as measured via the Kainos ELISA FGF-23 kit, (2) to calculate a reference interval, and (3) to assess the correlation of the FGF-23 concentration with the hematological and biochemical parameters. The coefficient of variation was below 15% for both the intra- and interassay precision, indicating good reproducibility. The reference interval ranged between 95.8 (90% confidence interval: 44.6; 139.2) and 695.1 pg/mL (598.7; 799.1) based on 136 clinically healthy dogs, classified as such according to the information of treating veterinarians as well as the unremarkable results of hematology and biochemistry. The FGF-23 concentration differed significantly between dogs aged <9 and ≥9 years (p = 0.045). Four groups of 10 dogs each were retrospectively formed based on the creatinine concentration classification according to the IRIS staging. Correlation was the strongest for the renal parameters. Statistically significant differences in the FGF-23 concentration were demonstrated between the study groups I and III (p < 0.001), I and IV (p < 0.001), and II and IV (p = 0.005). There was a trend for a rising FGF-23 concentration in older dogs. Due to the wide reference interval, diagnostic cut-offs and/or subject-based FGF-23 reference values in each dog are needed for monitoring and clinical interpretation.
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Affiliation(s)
- Sandra Lapsina
- LABOKLIN GmbH and Co. KG, Steubenstraße 4, 97688 Bad Kissingen, Germany; (S.L.)
| | - Nicole Nagler
- LABOKLIN GmbH and Co. KG, Steubenstraße 4, 97688 Bad Kissingen, Germany; (S.L.)
| | - Simon Franz Müller
- LABOKLIN GmbH and Co. KG, Steubenstraße 4, 97688 Bad Kissingen, Germany; (S.L.)
| | - Annette Holtdirk
- Dr. MED. Kottmann—Clinical Research Organization, Beverstraße 64, 59077 Hamm, Germany
| | - Tanja Kottmann
- Dr. MED. Kottmann—Clinical Research Organization, Beverstraße 64, 59077 Hamm, Germany
| | - Elisabeth Müller
- LABOKLIN GmbH and Co. KG, Steubenstraße 4, 97688 Bad Kissingen, Germany; (S.L.)
| | - Ingo Schäfer
- LABOKLIN GmbH and Co. KG, Steubenstraße 4, 97688 Bad Kissingen, Germany; (S.L.)
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Vervloet MG. Shedding Light on the Complex Regulation of FGF23. Metabolites 2022; 12:metabo12050401. [PMID: 35629904 PMCID: PMC9147863 DOI: 10.3390/metabo12050401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/23/2022] [Accepted: 04/26/2022] [Indexed: 12/10/2022] Open
Abstract
Early research has suggested a rather straightforward relation between phosphate exposure, increased serum FGF23 (Fibroblast Growth Factor 23) concentrations and clinical endpoints. Unsurprisingly, however, subsequent studies have revealed a much more complex interplay between autocrine and paracrine factors locally in bone like PHEX and DMP1, concentrations of minerals in particular calcium and phosphate, calciprotein particles, and endocrine systems like parathyroid hormone PTH and the vitamin D system. In addition to these physiological regulators, an expanding list of disease states are shown to influence FGF23 levels, usually increasing it, and as such increase the burden of disease. While some of these physiological or pathological factors, like inflammatory cytokines, may partially confound the association of FGF23 and clinical endpoints, others are in the same causal path, are targetable and hence hold the promise of future treatment options to alleviate FGF23-driven toxicity, for instance in chronic kidney disease, the FGF23-associated disease with the highest prevalence by far. These factors will be reviewed here and their relative importance described, thereby possibly opening potential means for future therapeutic strategies.
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Affiliation(s)
- Marc G. Vervloet
- Amsterdam UMC, Location Vrije Universiteit Amsterdam, Nephrology, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands; ; Tel.: +31-20-4442671
- Amsterdam Cardiovascular Sciences, Diabetes and Metabolism, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
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Kongtasai T, Paepe D, Meyer E, Mortier F, Marynissen S, Stammeleer L, Defauw P, Daminet S. Renal biomarkers in cats: A review of the current status in chronic kidney disease. J Vet Intern Med 2022; 36:379-396. [PMID: 35218249 PMCID: PMC8965260 DOI: 10.1111/jvim.16377] [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: 12/23/2020] [Revised: 01/17/2022] [Accepted: 01/19/2022] [Indexed: 12/22/2022] Open
Abstract
Serum creatinine concentration, the classical biomarker of chronic kidney disease (CKD) in cats, has important limitations that decrease its value as a biomarker of early CKD. Recently, serum symmetric dimethylarginine concentration was introduced as a novel glomerular filtration rate biomarker for the early detection of CKD in cats. However, data on its specificity are still limited. The limitations of conventional biomarkers and the desire for early therapeutic intervention in cats with CKD to improve outcomes have prompted the discovery and validation of novel renal biomarkers to detect glomerular or tubular dysfunction. Changes in the serum or urinary concentrations of these biomarkers may indicate early kidney damage or predict the progression of kidney before changes in conventional biomarkers are detectable. This review summarizes current knowledge on renal biomarkers in CKD in cats, a field that has progressed substantially over the last 5 years.
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Affiliation(s)
- Thirawut Kongtasai
- Small Animal Department, Faculty of Veterinary Science, Ghent University, Merelbeke, Belgium.,Department of Clinical Sciences and Public Health, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand
| | - Dominique Paepe
- Small Animal Department, Faculty of Veterinary Science, Ghent University, Merelbeke, Belgium
| | - Evelyne Meyer
- Department of Pharmacology, Toxicology and Biochemistry, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Femke Mortier
- Small Animal Department, Faculty of Veterinary Science, Ghent University, Merelbeke, Belgium
| | - Sofie Marynissen
- Small Animal Department, Faculty of Veterinary Science, Ghent University, Merelbeke, Belgium
| | - Lisa Stammeleer
- Small Animal Department, Faculty of Veterinary Science, Ghent University, Merelbeke, Belgium
| | - Pieter Defauw
- Lumbry Park Veterinary Specialists, Alton, United Kingdom
| | - Sylvie Daminet
- Small Animal Department, Faculty of Veterinary Science, Ghent University, Merelbeke, Belgium
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Grigore TV, Zuidscherwoude M, Witasp A, Barany P, Wernerson A, Bruchfeld A, Xu H, Olauson H, Hoenderop J. Fibroblast growth factor 23 is independently associated with renal magnesium handling in patients with chronic kidney disease. Front Endocrinol (Lausanne) 2022; 13:1046392. [PMID: 36699036 PMCID: PMC9869122 DOI: 10.3389/fendo.2022.1046392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 11/28/2022] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Disturbances in magnesium homeostasis are common in patients with chronic kidney disease (CKD) and are associated with increased mortality. The kidney is a key organ in maintaining normal serum magnesium concentrations. To this end, fractional excretion of magnesium (FEMg) increases as renal function declines. Despite recent progress, the hormonal regulation of renal magnesium handling is incompletely understood. Fibroblast Growth Factor 23 (FGF23) is a phosphaturic hormone that has been linked to renal magnesium handling. However, it has not yet been reported whether FGF23 is associated with renal magnesium handling in CKD patients. METHODS The associations between plasma FGF23 levels, plasma and urine magnesium concentrations and FEMg was investigated in a cross-sectional cohort of 198 non-dialysis CKD patients undergoing renal biopsy. RESULTS FGF23 was significantly correlated with FEMg (Pearson's correlation coefficient = 0.37, p<0.001) and urinary magnesium (-0.14, p=0.04), but not with plasma magnesium. The association between FGF23 and FEMg remained significant after adjusting for potential confounders, including estimated glomerular filtration rate (eGFR), parathyroid hormone and 25-hydroxyvitamin D. CONCLUSIONS We report that plasma FGF23 is independently associated with measures of renal magnesium handling in a cohort of non-dialysis CKD patients. A potential causal relationship should be investigated in future studies.
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Affiliation(s)
- Teodora V. Grigore
- Radboud Institute for Molecular Life Sciences, Department of Physiology, Radboudumc, Nijmegen, Netherlands
| | - Malou Zuidscherwoude
- Radboud Institute for Molecular Life Sciences, Department of Physiology, Radboudumc, Nijmegen, Netherlands
| | - Anna Witasp
- Karolinska Institutet, Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Stockholm, Sweden
| | - Peter Barany
- Karolinska Institutet, Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Stockholm, Sweden
| | - Annika Wernerson
- Karolinska Institutet, Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Stockholm, Sweden
| | - Annette Bruchfeld
- Karolinska Institutet, Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Stockholm, Sweden
- Linköpings universitet Hälsouniversitetet, Department of Health, Medicine and Caring Sciences, Linköping, Sweden
| | - Hong Xu
- Karolinska Institutet, Division of Clinical Geriatrics, Department of Neurobiology, Department of Care Sciences and Society, Stockholm, Sweden
| | - Hannes Olauson
- Karolinska Institutet, Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Stockholm, Sweden
| | - Joost Hoenderop
- Radboud Institute for Molecular Life Sciences, Department of Physiology, Radboudumc, Nijmegen, Netherlands
- *Correspondence: Joost Hoenderop,
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8
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Stockman J, Villaverde C. Concerns related to dietary phosphorus intake in cats. J Am Vet Med Assoc 2021; 258:1325-1331. [PMID: 34061616 DOI: 10.2460/javma.258.12.1325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Laflamme D, Backus R, Brown S, Butterwick R, Czarnecki-Maulden G, Elliott J, Fascetti A, Polzin D. A review of phosphorus homeostasis and the impact of different types and amounts of dietary phosphate on metabolism and renal health in cats. J Vet Intern Med 2020; 34:2187-2196. [PMID: 33159358 PMCID: PMC7694857 DOI: 10.1111/jvim.15961] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 10/11/2020] [Accepted: 10/27/2020] [Indexed: 12/14/2022] Open
Abstract
Elevated concentrations of serum phosphate are linked with progression and increased case fatality rate in animals and humans with chronic kidney disease. Elevated concentrations of serum phosphate can be a risk factor for development of renal and cardiovascular diseases or osteoporosis in previously healthy people. In rodents, an excess intake of dietary phosphorus combined with an inverse dietary calcium : phosphorus ratio (<1 : 1) contributes to renal calcification. Renal injury also has occured in cats fed experimental diets supplemented with highly soluble phosphate salts, especially in diets with inverse calcium : phosphorus ratios. However, not all phosphorus sources contribute similarly to this effect. This review, which focuses on cats, summarizes the published evidence regarding phosphorus metabolism and homeostasis, including the relative impact of different dietary phosphorus sources, and their impact on the kidneys. No data currently shows that commercial cat foods induce renal injury. However, some diets contain high amounts of phosphorus relative to recommendations and some have inverse Ca : P ratios and so could increase the risk for development of kidney disease. While limiting the use of highly soluble phosphates appears to be important, there are insufficient data to support a specific upper limit for phosphate intake. This review also proposes areas where additional research is needed in order to strengthen conclusions and recommendations regarding dietary phosphorus for cats.
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Affiliation(s)
| | - Robert Backus
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Scott Brown
- College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | | | | | - Jonathan Elliott
- Royal Veterinary College, University of London, London, United Kingdom
| | - Andrea Fascetti
- Department of Molecular Biosciences, University of California, Davis, California, USA
| | - David Polzin
- Veterinary Clinical Sciences Department, College of Veterinary Medicine, University of Minnesota, St Paul, Minnesota, USA
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Holovakha VI, Mostovyi EV, Sliusarenko AO, Piddubnyak OV, Suslova NI, Matsinovich MS. Macronutrient status and indicators of acid-alkaline blood balance in cats with chronic renal failure. REGULATORY MECHANISMS IN BIOSYSTEMS 2020. [DOI: 10.15421/022039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Chronic renal failure is a common pathology among cats. According to various literary sources, this pathology is found in 0.5–14.0% of cats. Pathology in cats in our studies is a consequence of glomerulonephritis. The diagnosis of chronic renal failure established on the basis of clinical, instrumental, and laboratory methods of blood and urine testing. Studies have found that chronic renal failure in cats is clinically characterized by apathy, anorexia, dry skin, odor of urea, vomiting, thirst, occurrence in the mouth of uremic ulcers (9.5% of patients), tachycardia (up to 177 beats per minute) tachypnoea (up to 45 respiratory movements per minute), hypertension. In the urine – hypostenuria, erythrocyturia, leukocyturia, kidney epithelium, hyaline and granular cylinders. According to echosonography – increase in echogenicity of the parenchyma, brain substance echone negative, cortico-brain differentiation erased. In the blood test – normochromic macrocytic anemia, thrombocytopenia, hyperazotemia (up to 27.9 mmol/L), hypercreatininemia (324 μmol/L), hyperuricemia (615 μmol/L), 4.6-fold increase in SDMA (symmetric dimethylargin). In chronic renal failure, cats have a significant change in the elemental composition of the blood. In particular, the Na+ content was increased by 3%, Ca2+ 1.6 times, P 2.1 times. Instead, the K+ level was reduced 1.9 times. Changes in acid-base equilibrium (ABE) were also detected: the pH decreased to 7.22; HCO3– by 34%, total CO2 by 32.3%, while anionic difference (AG) and buffer bases (BE) increased by 1.8 and 3.5 times, respectively. Such changes are characteristic of the development of lactic acidosis. The obtained experimental data on changes in mineral metabolism and acid-base equilibrium in the serum of cats in chronic renal failure supplement and clarify information on the pathogenic pathology of the kidneys in cats aged 5–10 years. Blood biochemical data can be used to improve early-stage diagnostics without clinical manifestations of chronic renal failure, their prevention and treatment, and to solve applied scientific problems in the field of nephrology and urology of small animals.
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Spencer S, Wheeler‐Jones C, Elliott J. Aldosterone and the mineralocorticoid receptor in renal injury: A potential therapeutic target in feline chronic kidney disease. J Vet Pharmacol Ther 2020; 43:243-267. [PMID: 32128854 PMCID: PMC8614124 DOI: 10.1111/jvp.12848] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/20/2020] [Accepted: 02/09/2020] [Indexed: 12/24/2022]
Abstract
There is a growing body of experimental and clinical evidence supporting mineralocorticoid receptor (MR) activation as a powerful mediator of renal damage in laboratory animals and humans. Multiple pathophysiological mechanisms are proposed, with the strongest evidence supporting aldosterone-induced vasculopathy, exacerbation of oxidative stress and inflammation, and increased growth factor signalling promoting fibroblast proliferation and deranged extracellular matrix homeostasis. Further involvement of the MR is supported by extensive animal model experiments where MR antagonists (such as spironolactone and eplerenone) abrogate renal injury, including ischaemia-induced damage. Additionally, clinical trials have shown MR antagonists to be beneficial in human chronic kidney disease (CKD) in terms of reducing proteinuria and cardiovascular events, though current studies have not evaluated primary end points which allow conclusions to made about whether MR antagonists reduce mortality or slow CKD progression. Although differences between human and feline CKD exist, feline CKD shares many characteristics with human disease including tubulointerstitial fibrosis. This review evaluates the evidence for the role of the MR in renal injury and summarizes the literature concerning aldosterone in feline CKD. MR antagonists may represent a promising therapeutic strategy in feline CKD.
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Affiliation(s)
- Sarah Spencer
- Comparative Biomedical SciencesThe Royal Veterinary CollegeLondonUK
| | | | - Jonathan Elliott
- Comparative Biomedical SciencesThe Royal Veterinary CollegeLondonUK
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12
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Katayama M, Ohata K, Miyazaki T, Katayama R, Wakamatsu N, Ohno M, Yamashita T, Oikawa T, Sugaya T, Miyazaki M. Renal expression and urinary excretion of liver-type fatty acid-binding protein in cats with renal disease. J Vet Intern Med 2020; 34:761-769. [PMID: 32087614 PMCID: PMC7096645 DOI: 10.1111/jvim.15721] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 01/20/2020] [Indexed: 12/26/2022] Open
Abstract
Background Liver‐type fatty acid‐binding protein (L‐FABP) is a biomarker for early detection of renal disease in humans. Liver‐type fatty acid‐binding protein is cytotoxic oxidation products secreted from proximal tubules under ischemia and oxidative stress. Objective To examine renal expression and quantify urinary excretion of L‐FABP in catswith renal disease. Animals One hundred and thirty‐four client‐owned cats including 34 cats with serum creatinine (sCre) values >1.6 mg/dL and 10 other cats that died in clinics. Methods Tissue expressions of L‐FABP were examined by reverse transcription polymerase chain reaction and Western blotting. Urinary L‐FABP (uL‐FABP) and serum L‐FABP (sL‐FABP) levels were determined by enzyme‐linked immunosorbent assay. Anti‐liver‐type fatty acid‐binding protein antibody immunostained renal sections. Results Feline kidneys express L‐FABP. Strong L‐FABP signals were observed in the lumens of proximal tubular cells in 5 cats with high uL‐FABP excretion, but not in 5 cats with low uL‐FABP excretion. In 9 normal cats, uL‐FABP index was <1.2 μg/g urinary creatinine (uCre). High uL‐FABP indexes (>10.0 μg/g uCre) were detected in 7 of 100 cats with low sCre (<1.6 mg/dL) and 18 of 44 cats with high sCre (>1.6 mg/dL). There was a weak correlation between L‐FABP index and sCre, serum symmetric dimethylarginine (SDMA), or blood urea nitrogen (BUN), and these correlation coefficients were increased by analyzing only data of cats with sCre >1.6 mg/dL. There was a weak correlation between u L‐FABP index and sL‐FABP in all tested cats, but not in cats with high sCre. Conclusions and Clinical Importance This study demonstrates correlations between L‐FABP and current renal biomarkers for chronic kidney disease in cats, such as sCre and SDMA. Liver‐type fatty acid‐binding protein may be a potential biomarker to predict early pathophysiological events in feline kidneys.
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Affiliation(s)
- Masaaki Katayama
- Faculty of Agriculture, Cooperative Department of Veterinary Clinical Medicine, Iwate University, Morioka, Iwate, Japan
| | | | - Tamako Miyazaki
- Faculty of Agriculture, Department of Biological Chemistry and Food Sciences, Iwate University, Morioka, Iwate, Japan
| | - Rieko Katayama
- Faculty of Agriculture, Department of Biological Chemistry and Food Sciences, Iwate University, Morioka, Iwate, Japan
| | - Nobuko Wakamatsu
- Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, Louisiana
| | - Misa Ohno
- Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, Louisiana
| | - Tetsuro Yamashita
- Faculty of Agriculture, Department of Biological Chemistry and Food Sciences, Iwate University, Morioka, Iwate, Japan
| | | | | | - Masao Miyazaki
- Faculty of Agriculture, Department of Biological Chemistry and Food Sciences, Iwate University, Morioka, Iwate, Japan
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Renal accumulation of prooxidant mineral elements and CKD in domestic cats. Sci Rep 2020; 10:3160. [PMID: 32081923 PMCID: PMC7035273 DOI: 10.1038/s41598-020-59876-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 01/17/2020] [Indexed: 01/16/2023] Open
Abstract
Felids have a high incidence of chronic kidney disease (CKD), for which the most common renal lesion is chronic interstitial nephritis (CIN). CIN can be induced by tissue oxidative stress, which is determined by the cellular balance of pro- and anti-oxidant metabolites. Fish-flavoured foods are more often fed to cats than dogs, and such foods tend to have higher arsenic content. Arsenic is a pro-oxidant metallic element. We propose that renal accumulation of pro-oxidant elements such as arsenic and depletion of anti-oxidant elements such as zinc, underpin the high incidence of CIN in domestic cats. Total arsenic and other redox-reactive metal elements were measured in kidneys (after acid-digestion) and urine (both by inductively-coupled plasma-mass spectrometry) of domestic cats (kidneys, n = 56; urine, n = 21), domestic dogs (kidneys, n = 54; urine, n = 28) and non-domesticated Scottish Wildcats (kidneys, n = 17). Renal lesions were graded by severity of CIN. In our randomly sampled population, CIN was more prevalent in domestic cat versus domestic dog (51%, n = 32 of 62 cats; 15%, 11 of 70 dogs were positive for CIN, respectively). CIN was absent from all Scottish wildcats. Tissue and urinary (corrected for creatinine) arsenic content was higher in domestic cats, relative to domestic dogs and wildcats. Urine arsenic was higher in domestic cats and dogs with CIN. Arsenobetaine, an organic and relatively harmless species of arsenic, was the primary form of arsenic found in pet foods. In summary, the kidneys of domestic cats appear to have greater levels of pro-oxidant trace elements, as compared to dogs and wildcats. Since there was no difference in renal arsenic levels in cats with or without CIN, renal arsenic accumulation does not appear a primary driver of excess CIN in cats. Given clear differences in renal handling of pro vs. anti-oxidant minerals between cats and dogs, further in vivo balance studies are warranted. These may then inform species-specific guidelines for trace element incorporation into commercial diets.
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Babler A, Schmitz C, Buescher A, Herrmann M, Gremse F, Gorgels T, Floege J, Jahnen-Dechent W. Microvasculopathy and soft tissue calcification in mice are governed by fetuin-A, magnesium and pyrophosphate. PLoS One 2020; 15:e0228938. [PMID: 32074140 PMCID: PMC7029863 DOI: 10.1371/journal.pone.0228938] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 01/27/2020] [Indexed: 12/18/2022] Open
Abstract
Calcifications can disrupt organ function in the cardiovascular system and the kidney, and are particularly common in patients with chronic kidney disease (CKD). Fetuin-A deficient mice maintained against the genetic background DBA/2 exhibit particularly severe soft tissue calcifications, while fetuin-A deficient C57BL/6 mice remain healthy. We employed molecular genetic analysis to identify risk factors of calcification in fetuin-A deficient mice. We sought to identify pharmaceutical therapeutic targets that could be influenced by dietary of parenteral supplementation. We studied the progeny of an intercross of fetuin-A deficient DBA/2 and C57BL/6 mice to identify candidate risk genes involved in calcification. We determined that a hypomorphic mutation of the Abcc6 gene, a liver ATP transporter supplying systemic pyrophosphate, and failure to regulate the Trpm6 magnesium transporter in kidney were associated with severity of calcification. Calcification prone fetuin-A deficient mice were alternatively treated with parenteral administration of fetuin-A dietary magnesium supplementation, phosphate restriction, or by or parenteral pyrophosphate. All treatments markedly reduced soft tissue calcification, demonstrated by computed tomography, histology and tissue calcium measurement. We show that pathological ectopic calcification in fetuin-A deficient DBA/2 mice is caused by a compound deficiency of three major extracellular and systemic inhibitors of calcification, namely fetuin-A, magnesium, and pyrophosphate. All three of these are individually known to contribute to stabilize protein-mineral complexes and thus inhibit mineral precipitation from extracellular fluid. We show for the first time a compound triple deficiency that can be treated by simple dietary or parenteral supplementation. This is of special importance in patients with advanced CKD, who commonly exhibit reduced serum fetuin-A, magnesium and pyrophosphate levels.
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Affiliation(s)
- Anne Babler
- Helmholtz Institute for Biomedical Engineering, Biointerface Lab, RWTH Aachen University Hospital, Aachen, Germany
| | - Carlo Schmitz
- Helmholtz Institute for Biomedical Engineering, Biointerface Lab, RWTH Aachen University Hospital, Aachen, Germany
| | - Andrea Buescher
- Helmholtz Institute for Biomedical Engineering, Biointerface Lab, RWTH Aachen University Hospital, Aachen, Germany
| | - Marietta Herrmann
- Helmholtz Institute for Biomedical Engineering, Biointerface Lab, RWTH Aachen University Hospital, Aachen, Germany
- IZKF Research Group Tissue Regeneration in Musculoskeletal Regeneration, Orthopedic Center for Musculoskeletal Research, University of Würzburg, Würzburg, Germany
| | - Felix Gremse
- Helmholtz Institute for Biomedical Engineering, Experimental Molecular Imaging, RWTH Aachen University Hospital, Aachen, Germany
| | - Theo Gorgels
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Juergen Floege
- Division of Nephrology and Clinical Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Willi Jahnen-Dechent
- Helmholtz Institute for Biomedical Engineering, Biointerface Lab, RWTH Aachen University Hospital, Aachen, Germany
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15
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Chacar FC, Kogika MM, Ferreira AC, Kanayama KK, Reche A. Total serum magnesium in cats with chronic kidney disease with nephrolithiasis. J Feline Med Surg 2019; 21:1172-1180. [PMID: 30694098 PMCID: PMC10814274 DOI: 10.1177/1098612x18823588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVES Magnesium has been 'the forgotten ion' for many years. Over the past decade, however, the role of magnesium in essential physiological functions and several illness conditions have been elucidated. Nevertheless, the investigation of magnesium in cats with chronic kidney disease (CKD) and nephrolithiasis is yet to be determined. The purpose of this study was to investigate whether CKD cats with nephrolithiasis have changes in total serum magnesium concentrations, and whether magnesium disorders may be associated with other electrolyte disturbances, as well as with prognosis. We also aimed to evaluate whether total serum magnesium concentration differs between CKD cats with and without nephrolithiasis. METHODS Total serum magnesium concentrations were assessed in 42 cats with CKD with stage 1-4 nephrolithiasis. The correlation between magnesium and other electrolytes, as well as Kaplan-Meier survival analysis, were performed. We also selected 14 control cats with CKD without nephrolithiasis age-matched with 14 cats with CKD with nephrolithiasis. RESULTS Hypermagnesemia was observed in 16/42 (38.1%) and hypomagnesemia in 6/42 (14.3%) cats. Serum magnesium abnormalities were observed in cats of all stages, and marked hypermagnesemia was noted in cats with stage 4 CKD with nephrolithiasis (P <0.001). There was a negative correlation between total serum magnesium and ionized calcium (r = -0.64; P <0.01), and a positive correlation between total serum magnesium and serum phosphorus (r = 0.58, P = 0.01). Cats with CKD with nephrolithiasis and hypomagnesemia or hypermagnesemia had higher mortality than those with normal total serum magnesium concentration (P <0.01), regardless of CKD stage. There was no difference in total serum magnesium concentration between CKD cats with and without nephrolithiasis. CONCLUSIONS AND RELEVANCE Cats with CKD with nephrolithiasis have magnesium abnormalities. Hypomagnesemia and hypermagnesemia were associated with an increase in mortality, and thus total serum magnesium abnormalities may be used as prognostic factors in these cases.
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Affiliation(s)
- Fernanda Chicharo Chacar
- Internal Medicine, School of Veterinary Medicine and Animal Science/University of Sao Paulo, Sao Paulo, Brazil
| | - Marcia Mery Kogika
- Internal Medicine, School of Veterinary Medicine and Animal Science/University of Sao Paulo, Sao Paulo, Brazil
| | - Andréa C Ferreira
- Internal Medicine, School of Veterinary Medicine and Animal Science/University of Sao Paulo, Sao Paulo, Brazil
| | - Khadine K Kanayama
- Internal Medicine, School of Veterinary Medicine and Animal Science/University of Sao Paulo, Sao Paulo, Brazil
| | - Archivaldo Reche
- Internal Medicine, School of Veterinary Medicine and Animal Science/University of Sao Paulo, Sao Paulo, Brazil
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Sargent HJ, Jepson RE, Chang YM, Biourge VC, Bijsmans ES, Elliott J. Fibroblast growth factor 23 and symmetric dimethylarginine concentrations in geriatric cats. J Vet Intern Med 2019; 33:2657-2664. [PMID: 31568615 PMCID: PMC6872607 DOI: 10.1111/jvim.15590] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 07/24/2019] [Indexed: 01/02/2023] Open
Abstract
Background Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone that is increased in azotemic cats with chronic kidney disease (CKD) and predictive of the onset of azotemia in older cats. The introduction of symmetric dimethylarginine (SDMA) as a biomarker of glomerular filtration rate has led to the identification of cats in which SDMA is increased, but plasma creatinine concentrations remains within reference range. There is currently little understanding of the metabolic changes present in such cats. Objectives To examine the relationship between plasma FGF23 and SDMA concentrations in non‐azotemic geriatric cats. Animals Records of a cross section of client‐owned cats (n = 143) without azotemic CKD. Methods Clinicopathological information was obtained from cats (≥ 9 years) from records of 2 first opinion practices. The relationship between plasma SDMA and FGF23 concentrations was examined using Spearman's correlation and variables compared using the Mann‐Whitney U test. Results Cats with increased SDMA concentrations had significantly higher plasma FGF23 (P < .001) and creatinine (P < .001) concentrations compared to cats with SDMA concentrations within reference range. A weak positive relationship was demonstrated between plasma FGF23 and SDMA concentrations (r = .35, P < .001) and between plasma FGF23 and creatinine (r = .23, P = .005) concentrations. Conclusions and Clinical Importance More cats with increased SDMA concentrations had higher FGF23 concentrations than those with SDMA concentrations within the reference range, suggesting the presence of an alteration in phosphate homeostasis. Further studies are warranted to identify influencing factors and to explore the utility of FGF23 concentration to inform management of cats with early stage CKD.
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Affiliation(s)
- Hannah J Sargent
- Department of Comparative Biomedical Science, Royal Veterinary College, University of London, London, United Kingdom
| | - Rosanne E Jepson
- Department of Clinical Science and Services Royal Veterinary College, University of London, London, United Kingdom
| | - Yu-Mei Chang
- Research Support Office, Royal Veterinary College, University of London, London, United Kingdom
| | | | | | - Jonathan Elliott
- Department of Comparative Biomedical Science, Royal Veterinary College, University of London, London, United Kingdom
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Bär L, Stournaras C, Lang F, Föller M. Regulation of fibroblast growth factor 23 (FGF23) in health and disease. FEBS Lett 2019; 593:1879-1900. [PMID: 31199502 DOI: 10.1002/1873-3468.13494] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 12/19/2022]
Abstract
Fibroblast growth factor 23 (FGF23) is mainly produced in the bone and, upon secretion, forms a complex with a FGF receptor and coreceptor αKlotho. FGF23 can exert several endocrine functions, such as inhibiting renal phosphate reabsorption and 1,25-dihydroxyvitamin D3 production. Moreover, it has paracrine activities on several cell types, including neutrophils and hepatocytes. Klotho and Fgf23 deficiencies result in pathologies otherwise encountered in age-associated diseases, mainly as a result of hyperphosphataemia-dependent calcification. FGF23 levels are also perturbed in the plasma of patients with several disorders, including kidney or cardiovascular diseases. Here, we review mechanisms controlling FGF23 production and discuss how FGF23 regulation is perturbed in disease.
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Affiliation(s)
- Ludmilla Bär
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Christos Stournaras
- Institute of Biochemistry, University of Crete Medical School, Heraklion, Greece
| | - Florian Lang
- Institute of Physiology, University of Tübingen, Germany
| | - Michael Föller
- Institute of Physiology, University of Hohenheim, Stuttgart, Germany
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18
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Effects of the long-term feeding of diets enriched with inorganic phosphorus on the adult feline kidney and phosphorus metabolism. Br J Nutr 2018; 121:249-269. [PMID: 30572965 PMCID: PMC6390406 DOI: 10.1017/s0007114518002751] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Renal disease has a high incidence in cats, and some evidence implicates dietary P as well. To investigate this further, two studies in healthy adult cats were conducted. Study 1 (36 weeks) included forty-eight cats, stratified to control or test diets providing 1·2 or 4·8 g/1000 kcal (4184 kJ) P (0 or approximately 3·6 g/1000 kcal (4184 kJ) inorganic P, Ca:P 1·2, 0·6). Study 2 (29 weeks) included fifty cats, stratified to control or test diets, providing 1·3 or 3·6 g/1000 kcal (4184 kJ) P (0 or approximately 1·5 g/1000 kcal (4184 kJ) inorganic P, Ca:P 1·2, 0·9). Health markers, glomerular filtration rate (GFR) and mineral balance were measured regularly, with abdominal ultrasound. Study 1 was halted after 4 weeks as the test group GFR reduced by 0·4 (95 % CI 0·3, 0·5) ml/min per kg, and ultrasound revealed changes in renal echogenicity. In study 2, at week 28, no change in mean GFR was observed (P >0·05); however, altered renal echogenicity was detected in 36 % of test cats. In agreement with previous studies, feeding a diet with Ca:P <1·0, a high total and inorganic P inclusion resulted in loss of renal function and changes in echogenicity suggestive of renal pathology. Feeding a diet containing lower total and inorganic P with Ca:P close to 1·0 led to more subtle structural changes in a third of test cats; however, nephrolithiasis occurred in both diet groups, complicating data interpretation. We conclude that the no observed adverse effects level for total dietary P in adult cats is lower than 3·6 g/1000 kcal (4184 kJ), however the effect of inorganic P sources and Ca:P require further investigation.
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van den Broek DHN, Chang YM, Elliott J, Jepson RE. Prognostic importance of plasma total magnesium in a cohort of cats with azotemic chronic kidney disease. J Vet Intern Med 2018; 32:1359-1371. [PMID: 29704284 PMCID: PMC6060321 DOI: 10.1111/jvim.15141] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 01/10/2018] [Accepted: 03/28/2018] [Indexed: 12/28/2022] Open
Abstract
Background Hypomagnesemia is associated with increased mortality and renal function decline in humans with chronic kidney disease (CKD). Magnesium is furthermore inversely associated with fibroblast growth factor 23 (FGF23), an important prognostic factor in CKD in cats. However, the prognostic significance of plasma magnesium in cats with CKD is unknown. Objectives To explore associations of plasma total magnesium concentration (tMg) with plasma FGF23 concentration, all‐cause mortality, and disease progression in cats with azotemic CKD. Animals Records of 174 client‐owned cats with IRIS stage 2‐4 CKD. Methods Cohort study. Cats with azotemic CKD were identified from the records of two London‐based first opinion practices (1999–2013). Possible associations of baseline plasma tMg with FGF23 concentration and risks of death and progression were explored using, respectively, linear, Cox, and logistic regression. Results Plasma tMg (reference interval, 1.73–2.57 mg/dL) was inversely associated with plasma FGF23 when controlling for plasma creatinine and phosphate concentrations (partial correlation coefficient, −0.50; P < .001). Hypomagnesemia was observed in 12% (20/174) of cats, and independently associated with increased risk of death (adjusted hazard ratio, 2.74; 95% confidence interval [CI], 1.35–5.55; P = .005). The unadjusted associations of hypermagnesemia (prevalence, 6%; 11/174 cats) with survival (hazard ratio, 2.88; 95% CI, 1.54–5.38; P = .001), and hypomagnesemia with progressive CKD (odds ratio, 17.7; 95% CI, 2.04–154; P = .009) lost significance in multivariable analysis. Conclusions and Clinical Importance Hypomagnesemia was associated with higher plasma FGF23 concentrations and increased risk of death. Measurement of plasma tMg augments prognostic information in cats with CKD, but whether these observations are associations or causations warrants further investigation.
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Affiliation(s)
- D Hendrik N van den Broek
- Department of Clinical Science and Services, Royal Veterinary College, University of London, London, United Kingdom
| | - Yu-Mei Chang
- Research Support Office, Royal Veterinary College, University of London, London, United Kingdom
| | - Jonathan Elliott
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, United Kingdom
| | - Rosanne E Jepson
- Department of Clinical Science and Services, Royal Veterinary College, University of London, London, United Kingdom
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