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Albrecht LV, Pereira RC, Salusky IB. All the might of the osteocyte: emerging roles in chronic kidney disease. Kidney Int 2023; 104:910-915. [PMID: 37648154 DOI: 10.1016/j.kint.2023.08.009] [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: 07/03/2023] [Revised: 08/04/2023] [Accepted: 08/11/2023] [Indexed: 09/01/2023]
Abstract
Osteocytes are the most abundant type of bone cell and play crucial roles in bone health. Osteocytes sense mechanical stress and orchestrate osteoblasts and osteoclasts to maintain bone density and strength. Beyond this, osteocytes have also emerged as key regulators of organ crosstalk, and they function as endocrine organs via their roles in secreting factors that mediate signaling within their neighboring bone cells and in distant tissues. As such, osteocyte dysfunction has been associated with the bone abnormalities seen across a spectrum of chronic kidney disease. Specifically, dysregulated osteocyte morphology and signaling have been observed in the earliest stages of chronic kidney disease and have been suggested to contribute to kidney disease progression. More important, US Food and Drug Administration-approved inhibitors of osteocytic secreted proteins, such as fibroblast growth factor 23 and sclerostin, have been used to treat bone diseases. The present mini review highlights new research that links dysfunctional osteocytes to the pathogenesis of chronic kidney disease mineral and bone disorder.
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Affiliation(s)
- Lauren V Albrecht
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, California, USA; Department of Pharmaceutical Sciences, School of Pharmacy, University of California, Irvine, Irvine, California, USA.
| | - Renata C Pereira
- Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Isidro B Salusky
- Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.
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2
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Lee TF, Tommasi S, Bersten A, Heilbronn LK, Sotgia S, Zinellu A, Carru C, Mangoni AA, Burt MG. Does hyperglycemia affect arginine metabolites in critically ill patients? A prospective cohort and in vitro study. Diabetol Metab Syndr 2023; 15:68. [PMID: 37005603 PMCID: PMC10067243 DOI: 10.1186/s13098-023-01035-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 03/22/2023] [Indexed: 04/04/2023] Open
Abstract
BACKGROUND Changes in the arginine metabolites asymmetric dimethyl-L-arginine (ADMA) and L-homoarginine and acute blood glucose concentrations have been shown to cause endothelial dysfunction and be independently associated with mortality in Intensive Care Unit (ICU) patients. The aim of this study was to investigate whether hyperglycemia potentially modulates these arginine metabolite concentrations to provide a mechanism that may link hyperglycemia and mortality in this patient group. METHODS A clinical and in vitro study were undertaken. Glucose, glycosylated hemoglobin-A1c (HbA1c) and the stress hyperglycemia ratio (SHR) (to quantify absolute, chronic and relative hyperglycemia respectively) were measured in 1155 acutely unwell adult patients admitted to a mixed medical-surgical ICU. SHR was calculated by dividing the admission glucose by the estimated average glucose over the last 3 months, which was derived from HbA1c. ADMA and L-homoarginine were measured in a plasma sample collected at admission to ICU by liquid chromatography tandem mass spectrometry. The activity of dimethylarginine-dimethylaminohydrolase 1 (DDAH1), the main enzyme regulating ADMA concentrations, was assessed at varying glucose concentrations in vitro by quantifying the conversion of ADMA to citrulline in HEK293 cells that overexpress DDAH1. RESULTS In the clinical study, plasma ADMA was not significantly associated with any measure of hyperglycemia. L-homoarginine was positively associated with glucose (β = 0.067, p = 0.018) and SHR (β = 0.107, p < 0.001) after correction for glomerular filtration rate. However, as L-homoarginine is a negative predictor of mortality, the direction of these associations are the opposite of those expected if hyperglycemia was affecting mortality via changes in L-homoarginine. In vitro DDAH1 activity was not significantly influenced by glucose concentrations (p = 0.506). CONCLUSION In critically ill patients the association between relative hyperglycemia and mortality is not mediated by changes in ADMA or L-homoarginine. Trial registration ANZCTR Trial ID ACTRN12615001164583.
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Affiliation(s)
- Tien F Lee
- College of Medicine and Public Health, Flinders University, Flinders Drive, Bedford Park, SA, 5042, Australia
- Southern Adelaide Diabetes and Endocrine Services, Flinders Medical Centre, Flinders Drive, Bedford Park, SA, 5042, Australia
| | - Sara Tommasi
- College of Medicine and Public Health, Flinders University, Flinders Drive, Bedford Park, SA, 5042, Australia
- Department of Clinical Pharmacology, Flinders Medical Centre, Southern Adelaide Local Health Network, Bedford Park, SA, 5042, Australia
| | - Andrew Bersten
- College of Medicine and Public Health, Flinders University, Flinders Drive, Bedford Park, SA, 5042, Australia
- Department of Critical Care Medicine, Flinders University, Bedford Park, South Australia, Australia
| | - Leonie K Heilbronn
- Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
| | - Salvatore Sotgia
- Department of Biomedical Sciences, School of Medicine, University of Sassari, Sassari, Italy
| | - Angelo Zinellu
- Department of Biomedical Sciences, School of Medicine, University of Sassari, Sassari, Italy
| | - Ciriaco Carru
- Department of Biomedical Sciences, School of Medicine, University of Sassari, Sassari, Italy
| | - Arduino A Mangoni
- College of Medicine and Public Health, Flinders University, Flinders Drive, Bedford Park, SA, 5042, Australia
- Department of Clinical Pharmacology, Flinders Medical Centre, Southern Adelaide Local Health Network, Bedford Park, SA, 5042, Australia
| | - Morton G Burt
- College of Medicine and Public Health, Flinders University, Flinders Drive, Bedford Park, SA, 5042, Australia.
- Southern Adelaide Diabetes and Endocrine Services, Flinders Medical Centre, Flinders Drive, Bedford Park, SA, 5042, Australia.
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Koch V, Gruenewald LD, Gruber‐Rouh T, Martin S, Eichler K, Booz C, Yel I, Vogl TJ, Buchner K, Hagenmueller M, März W, Frey N, Hardt SE, Riffel JH. Homoarginine treatment of rats improves cardiac function and remodeling in response to pressure overload. Fundam Clin Pharmacol 2022; 36:992-1004. [DOI: 10.1111/fcp.12808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Vitali Koch
- Goethe University Frankfurt Frankfurt am Main Germany
- Department of Cardiology, Angiology, and Pulmonology Heidelberg University Hospital Heidelberg Germany
| | | | | | - Simon Martin
- Goethe University Frankfurt Frankfurt am Main Germany
| | | | | | - Ibrahim Yel
- Goethe University Frankfurt Frankfurt am Main Germany
| | | | - Kristina Buchner
- Institute of Human Genetics, Section for Developmental Genetics University of Heidelberg Heidelberg Germany
| | - Marco Hagenmueller
- Department of Cardiology, Angiology, and Pulmonology Heidelberg University Hospital Heidelberg Germany
| | - Winfried März
- Synlab Academy Synlab Holding Deutschland GmbH Augsburg Germany
| | - Norbert Frey
- Department of Cardiology, Angiology, and Pulmonology Heidelberg University Hospital Heidelberg Germany
| | - Stefan E. Hardt
- Department of Cardiology, Angiology, and Pulmonology Heidelberg University Hospital Heidelberg Germany
| | - Johannes H. Riffel
- Department of Cardiology, Angiology, and Pulmonology Heidelberg University Hospital Heidelberg Germany
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4
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Wetzel MD, Stanley K, Maity S, Madesh M, Bopassa JC, Awad AS. Homoarginine ameliorates diabetic nephropathy independent of nitric oxide synthase-3. Physiol Rep 2021; 9:e14766. [PMID: 33713581 PMCID: PMC7955794 DOI: 10.14814/phy2.14766] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 02/07/2023] Open
Abstract
Recently we showed that homoarginine supplementation confers kidney protection in diabetic mouse models. In this study we tested whether the protective effect of homoarginine is nitric oxide synthase-3 (NOS3)-independent in diabetic nephropathy (DN). Experiments were conducted in NOS3 deficient (NOS3-/- ) mice and their wild type littermate using multiple low doses of vehicle or streptozotocin and treated with homoarginine via drinking water for 24 weeks. Homoarginine supplementation for 24 weeks in diabetic NOS3-/- mice significantly attenuated albuminuria, increased blood urea nitrogen, histopathological changes and kidney fibrosis, kidney fibrotic markers, and kidney macrophage recruitment compared with vehicle-treated diabetic NOS3-/- mice. Furthermore, homoarginine supplementation restored kidney mitochondrial function following diabetes. Importantly, there were no significant changes in kidney NOS1 or NOS2 mRNA expression between all groups. In addition, homoarginine supplementation improved cardiac function and reduced cardiac fibrosis following diabetes. These data demonstrate that the protective effect of homoarginine is independent of NOS3, which will ultimately change our understanding of the mechanism(s) by which homoarginine induce renal and cardiac protection in DN. Homoarginine protective effect in DN could be mediated via improving mitochondrial function.
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Affiliation(s)
- Michael D. Wetzel
- Department of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTXUSA
| | - Kristen Stanley
- Department of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTXUSA
| | - Soumya Maity
- Department of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTXUSA
| | - Muniswamy Madesh
- Department of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTXUSA
| | - Jean C. Bopassa
- Department of Cellular and Integrative PhysiologyUniversity of Texas Health Science Center at San AntonioSan AntonioTXUSA
| | - Alaa S. Awad
- Department of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTXUSA
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Wetzel MD, Gao T, Venkatachalam M, Morris SM, Awad AS. l-Homoarginine supplementation prevents diabetic kidney damage. Physiol Rep 2019; 7:e14235. [PMID: 31552707 PMCID: PMC6759505 DOI: 10.14814/phy2.14235] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 08/27/2019] [Indexed: 12/22/2022] Open
Abstract
l-homoarginine is an endogenous, non-proteinogenic amino acid that has emerged as a new player in health and disease. Specifically, low l-homoarginine levels are associated with cardiovascular diseases, stroke, and reduced kidney function. However, the role of l-homoarginine in the pathogenesis of diabetic nephropathy (DN) is not known. Experiments were conducted in 6-week-old Ins2Akita mice supplemented with l-homoarginine via drinking water or mini osmotic pump for 12 weeks. Both plasma and kidney l-homoarginine levels were significantly reduced in diabetic mice compared to nondiabetic controls. Untreated Ins2Akita mice showed significant increases in urinary albumin excretion, histological changes, glomerular macrophage recruitment, the inflammatory cytokine KC-GRO/CXCL1, and urinary thiobarbituric acid reactive substances (TBARS) excretion as an indicator of oxidative stress, along with a significant reduction in kidney nitrate + nitrite levels compared to control mice at 18 weeks of age. In contrast, l-homoarginine supplementation for 12 weeks in Ins2Akita mice, via either drinking water or mini osmotic pump, significantly reduced albuminuria, renal histological changes, glomerular macrophage recruitment, KC-GRO/CXCL1 levels, urinary TBARS excretion, and largely restored kidney nitrate + nitrite levels. These data demonstrate that l-homoarginine supplementation attenuates specific features of DN in mice and could be a potential new therapeutic tool for treating diabetic patients.
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Affiliation(s)
- Michael D. Wetzel
- Department of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTexas
| | - Ting Gao
- Department of MedicinePenn State University College of MedicineHersheyPennsylvania
| | - Manjeri Venkatachalam
- Department of PathologyUniversity of Texas Health Science Center at San AntonioSan AntonioTexas
| | - Sidney M. Morris
- Department of Microbiology & Molecular GeneticsUniversity of PittsburghPittsburghPennsylvania
| | - Alaa S. Awad
- Department of MedicineUniversity of Texas Health Science Center at San AntonioSan AntonioTexas
- Department of MedicinePenn State University College of MedicineHersheyPennsylvania
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Zinellu A, Paliogiannis P, Carru C, Mangoni AA. Homoarginine and all-cause mortality: A systematic review and meta-analysis. Eur J Clin Invest 2018; 48:e12960. [PMID: 29806958 DOI: 10.1111/eci.12960] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 05/24/2018] [Indexed: 12/23/2022]
Abstract
BACKGROUND Homoarginine, a basic amino acid and analogue of L-arginine, has been shown to exert salutary effects on vascular homoeostasis, possibly through interaction with the enzymes nitric oxide synthase and arginase. This might translate into improved survival outcomes, particularly in subjects with moderate-high cardiovascular risk. We conducted a systematic review and meta-analysis to investigate the association between circulating homoarginine concentrations and all-cause mortality in observational studies of human cohorts. MATERIALS AND METHODS Studies reporting baseline circulating homoarginine concentrations and all-cause mortality as outcome were searched using the MEDLINE, Scopus and Cochrane databases until January 2018. Hazard ratios (HRs) with 95% confidence intervals (CIs) derived from multivariate Cox's proportional-hazards analysis were extracted from individual studies. RESULTS A total of 13 studies in 11 964 participants were included in the final analysis. Homoarginine concentrations were inversely associated with all-cause mortality (HR 0.64, 95% CI 0.57-0.73). This association remained significant in participant sub-groups with predominant cardiovascular disease (HR 0.64, 95% CI 0.55-0.76) and renal disease (HR 0.60, 95% CI 0.46-0.68). CONCLUSIONS This meta-analysis of observational studies showed an inverse association between circulating homoarginine concentrations and all-cause mortality. Further research is warranted to investigate the direct effects of homoarginine on cardiovascular homoeostasis, the associations between homoarginine and all-cause mortality in other population groups, and the effects of interventions on homoarginine concentrations on clinical outcomes.
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Affiliation(s)
- Angelo Zinellu
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | | | - Ciriaco Carru
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy.,Quality Control Unit, University Hospital (AOUSS), Sassari, Italy
| | - Arduino A Mangoni
- Department of Clinical Pharmacology, College of Medicine and Public Health, Flinders University and Flinders Medical Centre, Adelaide, Australia
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L-Homoarginine and its AGXT2-metabolite GOCA in chronic kidney disease as markers for clinical status and prognosis. Amino Acids 2018; 50:1347-1356. [PMID: 29982953 DOI: 10.1007/s00726-018-2610-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 06/27/2018] [Indexed: 02/07/2023]
Abstract
Plasma concentrations of L-homoarginine (hArg) are an emerging marker for clinical status and prognosis in renal and cardiovascular disease. Lowered hArg concentrations are associated with higher risk for these conditions, although a clear pathophysiological explanation for this association has not been established. Baseline plasma samples of patients with different stages of chronic kidney disease (CKD) (n = 527) were obtained from the CARE FOR HOMe study and were analyzed for hArg and, for the first time, its metabolite 6-guanidino-2-oxocaproic acid (GOCA) by isotope dilution LC-MS/MS methods. GOCA is converted from hArg by the enzyme alanine:glyoxylate aminotransferase 2 (AGXT2), which is also in the focus of current cardiovascular research. hArg levels ranged from 0.20-4.01 µmol/L with a median of 1.42 µmol/L, whereas GOCA levels were 0.08-25.82 nmol/L with a median of 1.45 nmol/L. hArg levels in the highest tertile (≥ 1.71 µmol/L) were associated with significantly lower risk for reaching the renal (hazard ratio 0.369, 95% confidence interval 0.028-0.655) or cardiovascular (HR 0.458, CI 0.295-0.712) endpoints in univariate Cox regression analysis. Inversely, GOCA levels in the highest tertile (≥ 2.13 nmol/L) were associated with increased renal (HR 3.807, CI 1.963-7.381) and cardiovascular (HR 1.611, CI 1.041-2.495) risk. A decreased ratio between hArg and GOCA predicted even more pronounced the risks for renal (HR 0.178, CI 0.087-0.363) and cardiovascular (HR 0.447, CI 0.281-0.709) events. However, adjustment for the confounders eGFR and albuminuria attenuated these findings. A pathophysiological role of an increased activity of AGXT2 in CKD should be evaluated in future clinical studies.
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Maestro de la Calle G, Fernández-Ruiz M, López-Medrano F, Polanco N, González E, San Juan R, Ruiz-Merlo T, Origüen J, Paz-Artal E, Andrés A, Aguado JM. Post-transplant hypocomplementemia: A novel marker of cardiovascular risk in kidney transplant recipients? Atherosclerosis 2018; 269:204-210. [PMID: 29407595 DOI: 10.1016/j.atherosclerosis.2018.01.021] [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: 05/29/2017] [Revised: 12/22/2017] [Accepted: 01/12/2018] [Indexed: 10/18/2022]
Abstract
BACKGROUND AND AIMS Cardiovascular disease (CVD) is a leading cause of mortality after kidney transplantation (KT). The potential role of the complement system in the pathogenesis of post-transplant CVD remains unexplored. METHODS Serum complement (C3 and C4) levels were measured at baseline and post-transplant months 1 and 6 in 447 kT recipients. The study outcome was post-transplant atherothrombotic event (PAE), a composite of acute coronary syndrome, critical peripheral arterial disease, stroke and/or transient ischemic attack. RESULTS After a median follow-up of 4.2 years, 48 PAEs occurred in 43 patients (cumulative incidence: 9.6%; incidence rate: 2.6 events per 100 transplant-years). No differences were found in C3 and C4 levels at baseline or month 1 between patients with or without PAE. However, C3 levels at month 6 were significantly lower in patients developing PAE beyond that point (i.e., late PAE) (96.9 ± 22.3 vs. 109.6 ± 24.0 mg/dL; p = 0.013). The presence of C3 hypocomplementemia at month 6 was associated with a lower PAE-free survival (p = 0.002). After adjusting for conventional CVD risk factors and acute graft rejection, C3 hypocomplementemia at month 6 remained as an independent risk factor for late PAE in all the exploratory models (minimum hazard ratio: 3.24; p = 0.011). With respect to a model exclusively based on clinical variables, the inclusion of C3 levels at month 6 improved predictive capacity (areas under ROC curves: 0.788 and 0.812, respectively). CONCLUSIONS Post-transplant monitoring of serum C3 levels might be useful to identify KT recipients at increased risk of CVD.
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Affiliation(s)
- Guillermo Maestro de la Calle
- Unit of Infectious Diseases, Hospital Universitario "12 de Octubre", Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain
| | - Mario Fernández-Ruiz
- Unit of Infectious Diseases, Hospital Universitario "12 de Octubre", Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain.
| | - Francisco López-Medrano
- Unit of Infectious Diseases, Hospital Universitario "12 de Octubre", Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain
| | - Natalia Polanco
- Department of Nephrology, Hospital Universitario "12 de Octubre", Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain
| | - Esther González
- Department of Nephrology, Hospital Universitario "12 de Octubre", Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain
| | - Rafael San Juan
- Unit of Infectious Diseases, Hospital Universitario "12 de Octubre", Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain
| | - Tamara Ruiz-Merlo
- Unit of Infectious Diseases, Hospital Universitario "12 de Octubre", Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain
| | - Julia Origüen
- Unit of Infectious Diseases, Hospital Universitario "12 de Octubre", Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain
| | - Estela Paz-Artal
- Department of Immunology, Hospital Universitario "12 de Octubre", Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain
| | - Amado Andrés
- Department of Nephrology, Hospital Universitario "12 de Octubre", Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain
| | - José María Aguado
- Unit of Infectious Diseases, Hospital Universitario "12 de Octubre", Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain
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Kayacelebi AA, Minović I, Hanff E, Frenay ARS, de Borst MH, Feelisch M, van Goor H, Bakker SJL, Tsikas D. Low plasma homoarginine concentration is associated with high rates of all-cause mortality in renal transplant recipients. Amino Acids 2017; 49:1193-1202. [PMID: 28429125 DOI: 10.1007/s00726-017-2420-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 04/10/2017] [Indexed: 12/18/2022]
Abstract
In renal transplant recipients (RTR), we recently found that low urinary excretion of homoarginine (hArg) is associated with mortality and graft failure. However, it is not known whether such prospective associations also hold true for plasma concentrations of hArg. In the present study, we therefore determined plasma concentrations of hArg in the same cohort, i.e. in 687 RTR (functioning graft ≥1 year), and in 140 healthy donors, before and after kidney donation. Plasma hArg concentrations were significantly lower in RTR compared to healthy controls [1.24 (0.95-1.63) µM vs. 1.58 (1.31-2.03) µM, P < 0.001], and kidney donation resulted in a decrease in plasma hArg concentration to 1.41 (1.10-1.81) µM (P < 0.001). In RTR, multivariable linear regression analysis revealed BMI (β = 0.124), heart rate (β = -0.091), pre-emptive transplantation (β = 0.078), antidiabetic medication (β = -0.091), eGFR (β = 0.272), plasma PTH (β = -0.098), uric acid (β = 0.137), alkaline phosphatase (β = -0.100), HDL (β = -0.111), NT-pro-BNP (β = -0.166), and urinary urea excretion (β = 0.139) as main determinants of plasma hArg (all P < 0.05). In RTR, plasma hArg concentration was inversely associated with all-cause [hazard ratio (HR) 0.59 (95% CI 0.50-0.70), P < 0.001] and cardiovascular mortality [HR 0.50 (0.39-0.66), P < 0.001], both expressed per standard deviation change in log-transformed hArg, independent of potential confounders. To conclude, our results suggest that the kidney is a major hArg production site and an important modulator of hArg homeostasis in the renal and cardiovascular systems. Moreover, low plasma hArg is independently associated with increased risk of cardiovascular mortality in RTR, which corroborates the cardiovascular importance of preserving kidney function after transplantation.
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Affiliation(s)
- Arslan Arinc Kayacelebi
- Centre of Pharmacology and Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Isidor Minović
- Nephrology, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Erik Hanff
- Centre of Pharmacology and Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Anne-Roos S Frenay
- Pathology and Medical Biology, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Martin H de Borst
- Nephrology, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Martin Feelisch
- Clinical and Experimental Sciences, Faculty of Medicine, NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Harry van Goor
- Pathology and Medical Biology, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Stephan J L Bakker
- Nephrology, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Dimitrios Tsikas
- Centre of Pharmacology and Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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A Novel Pathway for Metabolism of the Cardiovascular Risk Factor Homoarginine by alanine:glyoxylate aminotransferase 2. Sci Rep 2016; 6:35277. [PMID: 27752063 PMCID: PMC5082758 DOI: 10.1038/srep35277] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 09/23/2016] [Indexed: 01/06/2023] Open
Abstract
Low plasma concentrations of L-homoarginine are associated with an increased risk of cardiovascular events, while homoarginine supplementation is protective in animal models of metabolic syndrome and stroke. Catabolism of homoarginine is still poorly understood. Based on the recent findings from a Genome Wide Association Study we hypothesized that homoarginine can be metabolized by alanine:glyoxylate aminotransferase 2 (AGXT2). We purified human AGXT2 from tissues of AGXT2 transgenic mice and demonstrated its ability to metabolize homoarginine to 6-guanidino-2-oxocaproic acid (GOCA). After incubation of HepG2 cells overexpressing AGXT2 with isotope-labeled homoarginine-d4 we were able to detect labeled GOCA in the medium. We injected wild type mice with labeled homoarginine and detected labeled GOCA in the plasma. We found that AGXT2 knockout (KO) mice have higher homoarginine and lower GOCA plasma levels as compared to wild type mice, while the reverse was true for AGXT2 transgenic (Tg) mice. In summary, we experimentally proved the presence of a new pathway of homoarginine catabolism – its transamination by AGXT2 with formation of GOCA and demonstrated that endogenous AGXT2 is required for maintenance of homoarginine levels in mice. Our findings may lead to development of novel therapeutic approaches for cardiovascular pathologies associated with homoarginine deficiency.
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Alesutan I, Feger M, Tuffaha R, Castor T, Musculus K, Buehling SS, Heine CL, Kuro-O M, Pieske B, Schmidt K, Tomaschitz A, Maerz W, Pilz S, Meinitzer A, Voelkl J, Lang F. Augmentation of phosphate-induced osteo-/chondrogenic transformation of vascular smooth muscle cells by homoarginine. Cardiovasc Res 2016; 110:408-418. [DOI: 10.1093/cvr/cvw062] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
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12
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Homoarginine in the renal and cardiovascular systems. Amino Acids 2015; 47:1703-13. [DOI: 10.1007/s00726-015-1993-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 04/18/2015] [Indexed: 10/23/2022]
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