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Smith ER, Champion de Crespigny PJ, Vally F, Hewitson TD, Toussaint ND, Cade TJ, Holt SG. Cord blood effectively resists mineralization through mechanisms that stabilize calciprotein particles. Kidney Int 2023; 103:782-786. [PMID: 36516910 DOI: 10.1016/j.kint.2022.11.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 11/13/2022] [Accepted: 11/23/2022] [Indexed: 12/14/2022]
Affiliation(s)
- Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia; Department of Medicine, University of Melbourne, Parkville, Melbourne, Victoria, Australia.
| | - Paul J Champion de Crespigny
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia; Department of Medicine, University of Melbourne, Parkville, Melbourne, Victoria, Australia; Department of Obstetrics and Gynaecology, The Royal Women's Hospital, Parkville, Melbourne, Victoria, Australia
| | - Fatima Vally
- Department of Obstetrics and Gynaecology, The Royal Women's Hospital, Parkville, Melbourne, Victoria, Australia
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia; Department of Medicine, University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia; Department of Medicine, University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - Thomas J Cade
- Department of Obstetrics and Gynaecology, The Royal Women's Hospital, Parkville, Melbourne, Victoria, Australia
| | - Stephen G Holt
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia; Department of Medicine, University of Melbourne, Parkville, Melbourne, Victoria, Australia
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Hewitson TD, Smith ER. Propagation, Culture, and Characterization of Renal Fibroblasts. Methods Mol Biol 2023; 2664:13-29. [PMID: 37423979 DOI: 10.1007/978-1-0716-3179-9_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The renal fibroblast, and phenotypically related myofibroblast, are universally present in all forms of progressive kidney disease. The in vitro study of the fibroblast, its behaviour, and factors affecting its activity is therefore key to understanding both its role and significance. In this protocol, we describe a reproducible method for selective propagation and culture of primary renal fibroblasts from kidney cortex. Techniques for their isolation, subculture, characterization, and cryogenic storage and retrieval are described in detail.
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Affiliation(s)
- Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia.
- Department of Medicine, University of Melbourne, Parkville, Melbourne, VIC, Australia.
| | - Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia
- Department of Medicine, University of Melbourne, Parkville, Melbourne, VIC, Australia
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Martin K, Venkatraman V, Agostinelli A, Thai B, Stäb D, Hewitson TD, Tan SJ, Toussaint ND, Robertson P. Magnetic Resonance Imaging (MRI) Analysis of Tissue Sodium Concentration in Chronic Kidney Disease. Methods Mol Biol 2023; 2664:161-171. [PMID: 37423989 DOI: 10.1007/978-1-0716-3179-9_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Human body sodium is regulated by the kidneys and extrarenal mechanisms. Stored skin and muscle tissue sodium accumulation is associated with kidney function decline, hypertension, and a pro-inflammatory and cardiovascular disease profile. In this chapter, we describe the use of sodium-hydrogen magnetic resonance imaging (23Na/1H MRI) to dynamically quantify tissue sodium concentration in the lower limb of humans. Real-time quantification of tissue sodium is calibrated against known sodium chloride aqueous concentrations. This method may be useful for investigating in vivo (patho-)physiological conditions associated with tissue sodium deposition and metabolism (including in relation to water regulation) to enlighten our understanding of sodium physiology.
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Affiliation(s)
- Kylie Martin
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia.
- Department of Medicine (RMH), University of Melbourne, Melbourne, VIC, Australia.
| | - Vijay Venkatraman
- Department of Radiology, The Royal Melbourne Hospital and The University of Melbourne, Parkville, Melbourne, VIC, Australia
| | - Angela Agostinelli
- Department of Radiology, The Royal Melbourne Hospital and The University of Melbourne, Parkville, Melbourne, VIC, Australia
| | - Braden Thai
- Department of Radiology, The Royal Melbourne Hospital and The University of Melbourne, Parkville, Melbourne, VIC, Australia
| | - Daniel Stäb
- MR Research Collaborations, Siemens Healthcare Pty Limited, Melbourne, VIC, Australia
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia
- Department of Medicine (RMH), University of Melbourne, Melbourne, VIC, Australia
| | - Sven-Jean Tan
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia
- Department of Medicine (RMH), University of Melbourne, Melbourne, VIC, Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia
- Department of Medicine (RMH), University of Melbourne, Parkville, Melbourne, VIC, Australia
| | - Patsy Robertson
- Department of Radiology, The Royal Melbourne Hospital and The University of Melbourne, Parkville, Melbourne, VIC, Australia
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Hewitson TD, Smith ER. Isolation of Rat Glomeruli and Propagation of Mesangial Cells to Study the Kidney in Health and Disease. Methods Mol Biol 2023; 2664:31-39. [PMID: 37423980 DOI: 10.1007/978-1-0716-3179-9_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Whole organ molecular analysis of the kidney potentially misses important factors involved in the pathogenesis of the glomerular disease. Organ-wide analysis therefore needs to be augmented by techniques that isolate enriched populations of glomeruli. Herein, we describe how differential sieving can be used to isolate a suspension of rat glomeruli from fresh tissue. Secondly, we also show how these can be used for the propagation of primary mesangial cell cultures. These protocols provide a practical approach for protein and RNA isolation for downstream analysis. These techniques are readily applicable to studies in isolated glomeruli in both experimental animal models and human kidney tissue.
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Affiliation(s)
- Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia.
- Department of Medicine, University of Melbourne, Parkville, Melbourne, VIC, Australia.
| | - Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia
- Department of Medicine, University of Melbourne, Parkville, Melbourne, VIC, Australia
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Thiem U, Hewitson TD, Toussaint ND, Holt SG, Haller MC, Pasch A, Cejka D, Smith ER. Effect of the phosphate binder sucroferric oxyhydroxide in dialysis patients on endogenous calciprotein particles, inflammation, and vascular cells. Nephrol Dial Transplant 2022; 38:1282-1296. [PMID: 36107466 PMCID: PMC10157755 DOI: 10.1093/ndt/gfac271] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Calciprotein particles (CPP), colloidal mineral-protein nanoparticles, have emerged as potential mediators of phosphate toxicity in dialysis patients, with putative links to vascular calcification, endothelial dysfunction, and inflammation. We hypothesized that phosphate binder therapy with sucroferric oxyhydroxide (SO) would reduce endogenous CPP levels, and attenuate pro-calcific and pro-inflammatory effects of patient serum towards human vascular cells in vitro.
Methods
This secondary analysis of a randomized, controlled cross-over study compared the effect of two-week phosphate binder washout with high-dose (2000 mg/d) and low-dose (250 mg/d) SO therapy in 28 hemodialysis patients on serum CPP levels, inflammatory cytokine/chemokine arrays, and human aortic smooth muscle cell (HASMC) and coronary artery endothelial cell (HCAEC) bioassays.
Results
In our cohort (75% male, 62 ± 12 years) high-dose SO reduced primary (amorphous) and secondary (crystalline) CPP levels [-62 (-76 to -44)%, P < 0.0001 and -38 (-62 to -0.14)%, P < 0.001, respectively] compared with washout. Nine of 14 plasma cytokines/chemokines significantly decreased with high-dose SO, with consistent reductions in Interleukin-6 (IL-6) and IL-8. Exposure of HASMC and HCAEC cultures to serum of SO-treated patients reduced calcification and markers of activation (IL-6, IL-8, and vascular cell adhesion protein 1) compared with washout. Serum-induced HASMC calcification and HCAEC activation was ameliorated by removal of the CPP-containing fraction from patient sera. Effects of CPP removal were confirmed in an independent cohort of chronic kidney disease patients.
Conclusions
High-dose SO reduced endogenous CPP formation in dialysis patients and yielded serum with attenuated pro-calcific and inflammatory effects in vitro.
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Affiliation(s)
- Ursula Thiem
- Dept. of Medicine III - Nephrology, Hypertension, Transplantation Medicine, Rheumatology, Geriatrics, Ordensklinikum Linz - Elisabethinen Hospital , Linz , Austria
- Johannes Kepler University Linz, Medical Faculty , Linz , Austria
| | - Tim D Hewitson
- Dept. of Nephrology, The Royal Melbourne Hospital , Parkville, Victoria , Australia
- Dept. of Medicine (RMH), The University of Melbourne , Parkville, Victoria , Australia
| | - Nigel D Toussaint
- Dept. of Nephrology, The Royal Melbourne Hospital , Parkville, Victoria , Australia
- Dept. of Medicine (RMH), The University of Melbourne , Parkville, Victoria , Australia
| | - Stephen G Holt
- Dept. of Medicine (RMH), The University of Melbourne , Parkville, Victoria , Australia
| | - Maria C Haller
- Dept. of Medicine III - Nephrology, Hypertension, Transplantation Medicine, Rheumatology, Geriatrics, Ordensklinikum Linz - Elisabethinen Hospital , Linz , Austria
- CeMSIIS - Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University Vienna , Vienna , Austria
| | - Andreas Pasch
- Calciscon AG , Nidau , Switzerland
- Lindenhofspital Bern , Bern , Switzerland
- Dept. of Physiology and Pathophysiology, Johannes Kepler University Linz , Linz , Austria
| | - Daniel Cejka
- Dept. of Medicine III - Nephrology, Hypertension, Transplantation Medicine, Rheumatology, Geriatrics, Ordensklinikum Linz - Elisabethinen Hospital , Linz , Austria
| | - Edward R Smith
- Dept. of Nephrology, The Royal Melbourne Hospital , Parkville, Victoria , Australia
- Dept. of Medicine (RMH), The University of Melbourne , Parkville, Victoria , Australia
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Bruell S, Nicholls KM, Hewitson TD, Talbot AS, Holt SG, Smith ER, Ruderman I. Reduced hip bone mineral density is associated with high levels of calciprotein particles in patients with Fabry disease. Osteoporos Int 2022; 33:1783-1794. [PMID: 35575807 PMCID: PMC9499881 DOI: 10.1007/s00198-022-06420-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 05/03/2022] [Indexed: 12/01/2022]
Abstract
UNLABELLED Calciprotein particles (CPP) are nanoscale mineralo-protein aggregates that help stabilize excess mineral in the circulation. We examined the relationship between CPP and bone mineral density in Fabry disease patients. We found an inverse correlation with total hip and femoral neck density, but none with lumbar spine. PURPOSE Calciprotein particles (CPP) are colloidal mineral-protein complexes made up primarily of the circulating glycoprotein fetuin-A, calcium, and phosphate. They form in extracellular fluid and facilitate the stabilization, transport, and clearance of excess minerals from the circulation. While most are monomers, they also exist in larger primary (CPP-I) and secondary (CPP-II) form, both of which are reported to be raised in pathological states. This study sought to investigate CPP levels in the serum of patients with Fabry disease, an X-linked systemic lysosomal storage disorder that is associated with generalized inflammation and low bone mineral density (BMD). METHODS We compared serum CPP-I and CPP-II levels in 59 patients with Fabry disease (37 female) with levels in an age-matched healthy adult cohort (n=28) and evaluated their association with BMD and biochemical data obtained from routine clinical review. RESULTS CPP-I and CPP-II levels were higher in male Fabry disease patients than female sufferers as well as their corresponding sex- and age-matched controls. CPP-II levels were inversely correlated with BMD at the total hip and femoral neck, but not the lumbar spine. Regression analyses revealed that these associations were independent of common determinants of BMD, but at the femoral neck, a significant association was only found in female patients. CONCLUSION Low hip BMD was associated with high CPP-II in patients with Fabry disease, but further work is needed to investigate the relevance of sex-related differences and to establish whether CPP measurement may aid assessment of bone disease in this setting.
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Affiliation(s)
- S Bruell
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia
| | - K M Nicholls
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Parkville, Australia
| | - T D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Parkville, Australia
| | - A S Talbot
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia
| | - S G Holt
- Department of Medicine (RMH), University of Melbourne, Parkville, Australia
- SEHA Kidney Care, Abu Dhabi Health Services Company, Abu Dhabi, United Arab Emirates
- Khalifa University, Abu Dhabi, United Arab Emirates
| | - E R Smith
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia.
- Department of Medicine (RMH), University of Melbourne, Parkville, Australia.
- Kincaid-Smith Renal Laboratories, Department of Nephrology, The Royal Melbourne Hospital, Grattan Street, Parkville, Victoria, 3052, Australia.
| | - I Ruderman
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Parkville, Australia
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Tiong MK, Smith ER, Pascoe EM, Elder GJ, Lioufas NM, Pedagogos E, Hawley CM, Valks A, Holt SG, Hewitson TD, Toussaint ND. Effect of lanthanum carbonate on serum calciprotein particles in patients with stage 3-4 CKD-results from a placebo-controlled randomized trial. Nephrol Dial Transplant 2022; 38:344-351. [PMID: 35212735 PMCID: PMC9923701 DOI: 10.1093/ndt/gfac043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Calciprotein particles (CPP) are colloidal aggregates of calcium phosphate and the mineral-binding protein fetuin-A, and are potential mediators of cardiovascular disease in chronic kidney disease (CKD). Emerging evidence suggests non-calcium-containing phosphate binders may reduce serum CPP in patients with kidney failure who require dialysis; however, it is unclear whether similar interventions are effective in patients with earlier stages of CKD. METHODS The IMpact of Phosphate Reduction On Vascular End-points in CKD (IMPROVE-CKD) was a multi-centre, placebo-controlled, randomized trial of lanthanum carbonate on cardiovascular markers in 278 participants with stage 3b/4 CKD. In this pre-specified exploratory analysis, primary (CPP-I) and secondary CPP (CPP-II) were measured in a sub-cohort of participants over 96 weeks. Treatment groups were compared using linear mixed-effects models and the relationship between serum CPP and pulse wave velocity (PWV) and abdominal aortic calcification (AAC) was examined. RESULTS A total of 253 participants had CPP data for baseline and at least one follow-up timepoint and were included in this analysis. The mean age was 62.4 ± 12.6 years, 32.0% were female and the mean estimated glomerular filtration rate (eGFR) was 26.6 ± 8.3 mL/min/1.73 m2. Baseline median serum CPP-I was 14.9 × 104 particles/mL [interquartile range (IQR) 4.6-49.3] and median CPP-II was 3.3 × 103 particles/mL (IQR 1.4-5.4). There was no significant difference between treatment groups at 96 weeks in CPP-I [22.8% (95% confidence interval -39.2, 36.4), P = 0.65] or CPP-II [-18.3% (95% confidence interval -40.0, 11.2), P = 0.20] compared with a placebo. Serum CPP were not correlated with baseline PWV or AAC, or with the progression of either marker. CONCLUSIONS Lanthanum carbonate was not associated with a reduction of CPP at 96 weeks when compared with a placebo in a CKD cohort.
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Affiliation(s)
| | - Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia,Department of Medicine (RMH), University of Melbourne, Parkville, Australia
| | - Elaine M Pascoe
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia
| | - Grahame J Elder
- University of Notre Dame, Sydney, Australia,University of Sydney, Sydney, Australia,Osteoporosis and Bone Biology Division, Garvan Institute of Medical Research, Darlinghurst, Australia,Department of Nephrology, Westmead Hospital, Sydney, Australia
| | - Nicole M Lioufas
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia,Department of Medicine (RMH), University of Melbourne, Parkville, Australia,Department of Nephrology, Western Health, Sunshine, Australia
| | | | - Carmel M Hawley
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia,Department of Nephrology, Princess Alexandra Hospital, Brisbane, Australia,Translational Research Institute, Brisbane, Queensland, Australia
| | - Andrea Valks
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia
| | - Stephen G Holt
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia,Department of Medicine (RMH), University of Melbourne, Parkville, Australia,SEHA Kidney Care, Abu Dhabi Health Services Company, Abu Dhabi, United Arab Emirates,Khalifa University, Abu Dhabi, United Arab Emirates
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia,Department of Medicine (RMH), University of Melbourne, Parkville, Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia,Department of Medicine (RMH), University of Melbourne, Parkville, Australia
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Thiem U, Hewitson TD, Toussaint ND, Haller MC, Pasch A, Cejka D, Smith E. MO722PHOSPHATE-BINDER THERAPY WITH SUCROFERRIC OXYHYDROXIDE REDUCES ENDOGENOUS CALCIPROTEIN PARTICLE FORMATION AND CRYSTALLIZATION IN A POST-HOC ANALYSIS OF A RANDOMIZED CONTROLLED TRIAL IN DIALYSIS PATIENTS. Nephrol Dial Transplant 2021. [DOI: 10.1093/ndt/gfab097.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background and Aims
Calcification propensity of serum can be measured with the so-called T50-test, which integrates the complex biological interplay of promoters and inhibitors of calciprotein particle formation in blood into a single readout. Calcification propensity is associated with the risk for cardiovascular events and death in dialysis patients. As we have recently demonstrated in a randomized, controlled, cross-over study in 39 chronic hemodialysis patients with hyperphosphatemia, lowering serum phosphate with high-dose phosphate-binder therapy with 2000 mg/d of sucroferric oxyhydroxide (SO) over two weeks reduces calcification propensity as determined by the T50-test compared to a two-week wash-out phase. Based on these results, we hypothesized that SO would influence endogenous calciprotein particle (CPP) formation and crystallization, i.e. conversion from primary to secondary CPP.
Method
To test this hypothesis, we conducted post-hoc analyses of the previously reported RCT (74% men, mean age 63±27 years, median dialysis vintage 24, IQR 16-36 months). Native serum CPP levels were measured by a fluorescent probe-based flow cytometric assay. Moreover, hydrodynamic radii (Rh) of secondary CPP formed after enrichment with exogenous calcium and phosphate was assessed by three-dimensional cross-correlation dynamic light scattering.
Results
Phosphate-binder therapy with SO lead to a reduction in serum phosphate levels from 2.28±0.5 mmol/l to 1.63±0.43 mmol/l (p<0.0001), accompanied by a significant reduction of endogenous calciprotein particle load and crystallization. Median (IQR) number of primary CPP decreased from 9.2x105 (7.7x105 - 12x105) particles/ml to 3.8 x105 (2.7x105 - 4.4x105) particles/ml (p<0.0001) and secondary CPP decreased from 5.4x104 (3.6x104 - 7.5x104) particles/ml to 3.2x104 (2.4x104 - 4.2x104) particles/ml (p<0.01, both by Wilcoxon matched-pairs test). Upon SO therapy we also observed a significant reduction of secondary calciprotein particle size as determined by Rh compared to phosphate-binder wash-out (214±55 nm vs. 231±52 nm, p<0.01 by paired t-test).
Conclusion
In chronic hemodialysis patients, lowering serum phosphate with SO is associated with a reduction in the load of primary and secondary CPP and a smaller size of secondary CPP.
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Affiliation(s)
- Ursula Thiem
- Ordensklinikum Linz - Elisabethinen Hospital, Department of Medicine III – Nephrology, Hypertension, Transplantation, Rheumatology, Geriatrics, Linz, Austria
| | - Tim D Hewitson
- The Royal Melbourne Hospital, Department of Nephrology, Parkville, Victoria, Australia
- The University of Melbourne, Department of Medicine, Melbourne, Australia
| | - Nigel D Toussaint
- The University of Melbourne, Department of Medicine, Melbourne, Australia
- The Royal Melbourne Hospital, Department of Nephrology, Parkville, Australia
| | - Maria C Haller
- Ordensklinikum Linz - Elisabethinen Hospital, Department of Medicine III – Nephrology, Hypertension, Transplantation, Rheumatology, Geriatrics, Linz, Austria
- Medical University Vienna, CeMSIIS - Center for Medical Statistics, Informatics, and Intelligent Systems, Vienna, Austria
| | - Andreas Pasch
- Calciscon AG, Nidau, Switzerland
- Lindenhofspital Bern, Bern, Switzerland
- Johannes Kepler University Linz, Department of Physiology and Pathophysiology, Linz, Austria
| | - Daniel Cejka
- Ordensklinikum Linz - Elisabethinen Hospital, Department of Medicine III – Nephrology, Hypertension, Transplantation, Rheumatology, Geriatrics, Linz, Austria
| | - Edward Smith
- The University of Melbourne, Department of Medicine, Melbourne, Australia
- The Royal Melbourne Hospital, Department of Nephrology, Parkville, Australia
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Tiong MK, Krishnasamy R, Smith ER, Hutchison CA, Ryan EG, Pascoe EM, Hawley CM, Hewitson TD, Jardine MJ, Roberts MA, Cho Y, Wong MG, Heath A, Nelson CL, Sen S, Mount PF, Vergara LA, Paul-Brent PA, Johnson DW, Toussaint ND. Effect of a medium cut-off dialyzer on protein-bound uremic toxins and mineral metabolism markers in patients on hemodialysis. Hemodial Int 2021; 25:322-332. [PMID: 33779046 DOI: 10.1111/hdi.12924] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/03/2021] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Hemodialysis (HD) with medium cut-off (MCO) dialyzers may expand molecular clearance, predominantly larger middle molecules (molecular weight 25-60 kDa). However, the impact of MCO dialyzers on long-term clearance of various other components of the uremic milieu is unknown. The tRial Evaluating Mid cut-Off Value membrane clearance of Albumin and Light chains in HemoDialysis patients (REMOVAL-HD) provided an opportunity to assess the effect of MCO dialyzers on protein-bound uremic toxins and novel markers of mineral metabolism. METHODS This exploratory sub-study of REMOVAL-HD evaluated changes in protein-bound solutes (total and free indoxyl sulfate [IS] and p-cresyl sulfate [PCS]) and mineral metabolism markers (intact fibroblast growth factor-23 [iFGF23], fetuin-A and endogenous calciprotein particles [CPP-1 and CPP-2]). Mid-week, pre-HD serum samples were collected at baseline and after 12 and 24 weeks of MCO use in stable adult patients. Change from baseline to Week 12 and 24 was estimated using linear mixed effects models. FINDINGS Eighty-nine participants were studied (mean age 67 ± 15 years, 38% female, 51% diabetic, median urine output 200 ml/24 h). Serum iFGF23 was reduced at Week 12 compared to baseline (-26.8% [95%CI -39.7, -11.1], p = 0.001), which was sustained at Week 24 (-21.7% [95%CI -35.7, -4.5], p = 0.012). There was no significant change in serum IS, PCS, fetuin-A, CPP-1, or CPP-2. DISCUSSION The use of a MCO dialyzer over 24 weeks was associated with a sustained reduction in FGF23, while other measured components of the uremic milieu were not significantly altered. Further studies are required to determine whether FGF23 reduction is associated with improved patient outcomes.
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Affiliation(s)
- Mark K Tiong
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Parkville, Australia
| | - Rathika Krishnasamy
- Department of Nephrology, Sunshine Coast University Hospital, Birtinya, Australia
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia
| | - Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Parkville, Australia
| | - Colin A Hutchison
- Department of Medicine, Hawke's Bay Hospital, Hawkes Bay, New Zealand
| | - Elizabeth G Ryan
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia
- QCIF Facility for Advanced Bioinformatics, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Elaine M Pascoe
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia
| | - Carmel M Hawley
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia
- Department of Nephrology, Princess Alexandra Hospital, Brisbane, Australia
- Translational Research Institute, Brisbane, Queensland, Australia
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Parkville, Australia
| | - Meg J Jardine
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
- The George Institute for Global Health, UNSW, Sydney, Australia
- SAN Renal Dialysis Unit, Sydney Adventist Hospital, Sydney, Australia
- Department of Nephrology, Concord Repatriation and General Hospital, Sydney, Australia
| | - Matthew A Roberts
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia
- Eastern Health Clinical School, Monash University, Melbourne, Australia
| | - Yeoungjee Cho
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia
- Department of Nephrology, Princess Alexandra Hospital, Brisbane, Australia
| | - Muh Geot Wong
- The George Institute for Global Health, UNSW, Sydney, Australia
- SAN Renal Dialysis Unit, Sydney Adventist Hospital, Sydney, Australia
| | - Anne Heath
- SAN Renal Dialysis Unit, Sydney Adventist Hospital, Sydney, Australia
| | - Craig L Nelson
- Department of Nephrology, Western Health, Melbourne, Australia
- Department of Medicine, Western Health, University of Melbourne, Melbourne, Australia
- Western Health Chronic Disease Alliance, Western Centre for Health Research and Education, Western Health, St Albans, Australia
| | - Shaundeep Sen
- Department of Nephrology, Concord Repatriation and General Hospital, Sydney, Australia
| | - Peter F Mount
- Department of Nephrology, Austin Health, Melbourne, Victoria, Australia
| | - Liza A Vergara
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia
| | - Peta-Anne Paul-Brent
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia
| | - David W Johnson
- Australasian Kidney Trials Network, The University of Queensland, Brisbane, Australia
- Department of Nephrology, Princess Alexandra Hospital, Brisbane, Australia
- Translational Research Institute, Brisbane, Queensland, Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Parkville, Australia
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Ruderman I, Hewitson TD, Smith ER, Holt SG, Wigg B, Toussaint ND. Vascular calcification in skin and subcutaneous tissue in patients with chronic and end-stage kidney disease. BMC Nephrol 2020; 21:279. [PMID: 32677907 PMCID: PMC7364566 DOI: 10.1186/s12882-020-01928-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 07/05/2020] [Indexed: 12/15/2022] Open
Abstract
Background Vascular calcification (VC) is well described in large- and medium-sized vessels in patients with chronic kidney disease (CKD), especially in those with end-stage kidney disease (ESKD) on dialysis. Medial calcification is particularly prevalent in this population and contributes to arterial stiffness and increased cardiovascular mortality and morbidity. Apart from in the setting of calciphylaxis, few studies have assessed skin and subcutaneous calcification and associations with abnormalities of bone and mineral metabolism in patients with CKD. Methods We performed a single-centre observational study to evaluate incisional skin tissue samples from three anatomical sites in patients with different stages of CKD undergoing elective surgery. We compared these samples to skin samples of a control cohort without CKD. Staining for calcification was performed with von Kossa method. A subgroup of skin samples were assessed by RT-PCR for upregulation of pro-calcific gene transcripts for tissue non-specific alkaline phosphatase (TNAP) and Runt-related transcription factor 2 (RUNX2). Results Forty-five patients were evaluated, 34 with CKD (including ESKD) and 11 control patients. VC was identified in 15 skin samples (13 CKD/ESKD and 2 controls). VC was present in the dermal and subcutaneous tissues of the neck, abdomen and arm samples. Two different histological types of VC were identified: speckled medial calcification and internal elastic lamina calcification. Presence of perieccrine calcification was identified in 14 samples, 10 with concurrent VC. There were no significant differences in serum parathyroid hormone, phosphate or calcium in patients with or without VC. Expression of TNAP or RUNX2 was not increased in samples from patients with ESKD or those with histological evidence of calcification. Conclusion This study reports the novel finding of dermal and subcutaneous calcification in multiple anatomical locations in 38% of patients with advanced CKD/ESKD undergoing elective surgery but free from calciphylaxis.
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Affiliation(s)
- Irene Ruderman
- Department of Nephrology, The Royal Melbourne Hospital, 300 Grattan St, Parkville, Victoria, 3050, Australia. .,Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia.
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, 300 Grattan St, Parkville, Victoria, 3050, Australia.,Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
| | - Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, 300 Grattan St, Parkville, Victoria, 3050, Australia.,Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
| | - Stephen G Holt
- Department of Nephrology, The Royal Melbourne Hospital, 300 Grattan St, Parkville, Victoria, 3050, Australia.,Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
| | - Belinda Wigg
- Department of Nephrology, The Royal Melbourne Hospital, 300 Grattan St, Parkville, Victoria, 3050, Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, 300 Grattan St, Parkville, Victoria, 3050, Australia.,Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
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11
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Holt SG, Yo JH, Karschimkus C, Volpato F, Christov S, Smith ER, Hewitson TD, Worth LJ, Champion De Crespigny P. Monitoring skin temperature at the wrist in hospitalised patients may assist in the detection of infection. Intern Med J 2020; 50:685-690. [PMID: 31908128 PMCID: PMC7318648 DOI: 10.1111/imj.14748] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 12/07/2019] [Accepted: 12/13/2019] [Indexed: 12/29/2022]
Abstract
Background Measuring temperature has always been a key observation in the diagnosis of infection. No studies have examined the usefulness of measuring temperature at the wrist to detect infection. Aim We sought to determine whether a watch measuring wrist temperature could accurately identify patients who are infected. Methods Prospective cross‐sectional pilot study of temperature monitoring in an unselected patients in a tertiary referral adult nephrology unit. Results One hundred and four data recording sessions revealed 88 useful data sets, with recording failures in the others. Patients were retrospectively classified as having no infection (Group A, n = 60), clinically diagnosed infection with less than 24 h of treatment with antibiotics (Group B, n = 5), and clinically diagnosed infection with greater than 24 h on antibiotics (Group C, n = 23). There was a significantly higher average maximum temperature in Group B (mean (SEM)) 38°C (0.6) compared with Groups A (36.1°C (0.1)) and C (36.3°C (0.3)). Based on receiver operating characteristics (ROC) a cut‐off temperature of ≥37.5°C gave sensitivity 80% and specificity 98%. Mean electrodermal activity was significantly higher in Groups B and C. Conclusions ROC of peripheral skin temperature measurements suggest that such a device may identify many patients requiring treatment for infection. This proof of principle study showed value in using a wearable device in the detection of infection and its potential as an early warning or monitoring device.
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Affiliation(s)
- Stephen G Holt
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia.,Department of Medicine, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jennifer H Yo
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia
| | - Connie Karschimkus
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia.,The Nursing Hub, The Royal Melbourne Hospital, Melbourne, Victoria, Australia
| | - Frank Volpato
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia
| | - Steve Christov
- Guidance Group, The Royal Melbourne Hospital, Melbourne, Victoria, Australia
| | - Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia.,Department of Medicine, The University of Melbourne, Melbourne, Victoria, Australia
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia.,Department of Medicine, The University of Melbourne, Melbourne, Victoria, Australia
| | - Leon J Worth
- Victorian Healthcare Associated Infection Surveillance System (VICNISS) Coordinating Centre, Doherty Institute, Melbourne, Victoria, Australia.,Sir Peter MacCallum Department of Oncology, National Centre for Infections in Cancer, Victorian Comprehensive Cancer Centre, University of Melbourne, Melbourne, Victoria, Australia
| | - Paul Champion De Crespigny
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia.,Department of Medicine, The University of Melbourne, Melbourne, Victoria, Australia
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12
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Smith ER, Hewitson TD, Holt SG. Diagnostic Tests for Vascular Calcification. Adv Chronic Kidney Dis 2019; 26:445-463. [PMID: 31831123 DOI: 10.1053/j.ackd.2019.07.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/22/2019] [Accepted: 07/28/2019] [Indexed: 02/06/2023]
Abstract
Vascular calcification (VC) is the heterogeneous endpoint of multiple vascular insults, which varies by arterial bed, the layer of the arterial wall affected, and is propagated by diverse cellular and biochemical mechanisms. A variety of in vivo and ex vivo techniques have been applied to the analysis of VC in preclinical studies, but clinical examination has principally relied on a number of noninvasive and invasive imaging modalities for detection and quantitation. Most imaging methods suffer from suboptimal spatial resolution, leading to the inability to distinguish medial from intimal VC and insufficient sensitivity to detect microcalcifications that are indicative of active mineral deposition and of vulnerable plaques which may be prone to rupture. Serum biomarkers lack specificity for VC and cannot discriminate pathology. Overall, uncertainties surrounding the sensitivity and specificity of different VC testing modalities, the absence of a clear cause-effect relationship, and lack of any evidence-based diagnostic or therapeutic protocols in relation to VC testing in chronic kidney disease has yielded weak or ungraded recommendations for their use in clinical practice. While VC is recognized as a key manifestation of chronic kidney disease-mineral and bone disorder and those with an increasing burden of VC are considered to be at higher cardiovascular risk, routine screening is not currently recommended.
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13
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Chow BSM, Kocan M, Shen M, Wang Y, Han L, Chew JY, Wang C, Bosnyak S, Mirabito-Colafella KM, Barsha G, Wigg B, Johnstone EKM, Hossain MA, Pfleger KDG, Denton KM, Widdop RE, Summers RJ, Bathgate RAD, Hewitson TD, Samuel CS. AT1R-AT2R-RXFP1 Functional Crosstalk in Myofibroblasts: Impact on the Therapeutic Targeting of Renal and Cardiac Fibrosis. J Am Soc Nephrol 2019; 30:2191-2207. [PMID: 31511361 DOI: 10.1681/asn.2019060597] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 07/29/2019] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Recombinant human relaxin-2 (serelaxin), which has organ-protective actions mediated via its cognate G protein-coupled receptor relaxin family peptide receptor 1 (RXFP1), has emerged as a potential agent to treat fibrosis. Studies have shown that serelaxin requires the angiotensin II (AngII) type 2 receptor (AT2R) to ameliorate renal fibrogenesis in vitro and in vivo. Whether its antifibrotic actions are affected by modulation of the AngII type 1 receptor (AT1R), which is expressed on myofibroblasts along with RXFP1 and AT2R, is unknown. METHODS We examined the signal transduction mechanisms of serelaxin when applied to primary rat renal and human cardiac myofibroblasts in vitro, and in three models of renal- or cardiomyopathy-induced fibrosis in vivo. RESULTS The AT1R blockers irbesartan and candesartan abrogated antifibrotic signal transduction of serelaxin via RXFP1 in vitro and in vivo. Candesartan also ameliorated serelaxin's antifibrotic actions in the left ventricle of mice with cardiomyopathy, indicating that candesartan's inhibitory effects were not confined to the kidney. We also demonstrated in a transfected cell system that serelaxin did not directly bind to AT1Rs but that constitutive AT1R-RXFP1 interactions could form. To potentially explain these findings, we also demonstrated that renal and cardiac myofibroblasts expressed all three receptors and that antagonists acting at each receptor directly or allosterically blocked the antifibrotic effects of either serelaxin or an AT2R agonist (compound 21). CONCLUSIONS These findings have significant implications for the concomitant use of RXFP1 or AT2R agonists with AT1R blockers, and suggest that functional interactions between the three receptors on myofibroblasts may represent new targets for controlling fibrosis progression.
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Affiliation(s)
- Bryna S M Chow
- Florey Institute of Neuroscience and Mental Health.,Department of Biochemistry and Molecular Biology, and
| | - Martina Kocan
- Florey Institute of Neuroscience and Mental Health.,Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Matthew Shen
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Yan Wang
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Lei Han
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Jacqueline Y Chew
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Chao Wang
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Sanja Bosnyak
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.,Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Katrina M Mirabito-Colafella
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Giannie Barsha
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Belinda Wigg
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Elizabeth K M Johnstone
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | | | - Kevin D G Pfleger
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia.,Department of Pharmacology and Therapeutics, ARC Centre for Personalised Therapeutic Technologies, Melbourne, Australia; and.,Dimerix Limited, Nedlands, Western Australia, Australia
| | - Kate M Denton
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Robert E Widdop
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Roger J Summers
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.,Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Ross A D Bathgate
- Florey Institute of Neuroscience and Mental Health.,Department of Biochemistry and Molecular Biology, and
| | - Tim D Hewitson
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Chrishan S Samuel
- Department of Biochemistry and Molecular Biology, and .,Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
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14
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Tan SJ, Chu MM, Toussaint ND, Cai MM, Hewitson TD, Holt SG. High-intensity physical exercise increases serum α-klotho levels in healthy volunteers. J Circ Biomark 2018; 7:1849454418794582. [PMID: 30147756 PMCID: PMC6100126 DOI: 10.1177/1849454418794582] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 07/02/2018] [Indexed: 01/16/2023] Open
Abstract
The recently discovered klotho proteins have roles in a diverse range of metabolic processes with the oldest protein, α-klotho, implicated in various cellular pathways in energy, glucose, and phosphate metabolism. Circulating soluble klotho (sKl), derived from membrane α-klotho cleavage, not only has effects on ion channels and insulin signaling pathways, but is inversely associated with mortality. Effects of physical exercise on sKl have not been well studied. The effect of a single high-intensity standardized exercise on sKl and serum phosphate (sPi) levels in healthy adults was investigated. A standard Bruce protocol treadmill exercise was undertaken by 10 fasting healthy volunteers. sKl, sPi, and blood glucose levels were measured in samples collected 1-week prior, immediately pre (Tpre), 0 (Tpost), 30 (T30), 240 (T240) min, and 1-week after exercise. Median (interquartile range) age of participants was 47.5 (44-51) years; five (50%) were male. All study participants achieved at least 90% predicted maximum heart rate (MHR). sKl increased acutely after exercise (Tpre median 448 pg/mL vs. Tpost median 576 pg/mL; p < 0.01). There was a nonsignificant sPi decline at T30 (Tpre 0.94 ± 0.12 mmol/L vs. T30 0.83 ± 0.22 mmol/L). Exercise led to a reduction in blood glucose by T240 with median glucose levels at Tpre, Tpost, T30, and T240 of 6.0, 6.5, 6.3, and 5.7 mmol/L, respectively. In conclusion, a single high-intensity exercise session is associated with a transient increase in sKl, a delayed reduction in blood glucose, and a nonsignificant decrease in sPi levels in healthy adults. The evaluation of long-term effects of cardiovascular fitness programs on sKl and sPi in healthy individuals and disease cohorts are required to identify potential lifestyle modifications to help improve chronic disease management and long-term outcomes.
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Affiliation(s)
- Sven-Jean Tan
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, VIC, Australia.,Department of Medicine, The University of Melbourne, Parkville, VIC, Australia
| | - Melissa M Chu
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, VIC, Australia.,Department of Medicine, The University of Melbourne, Parkville, VIC, Australia
| | - Michael Mx Cai
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, VIC, Australia.,Department of Medicine, The University of Melbourne, Parkville, VIC, Australia
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, VIC, Australia.,Department of Medicine, The University of Melbourne, Parkville, VIC, Australia
| | - Stephen G Holt
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, VIC, Australia.,Department of Medicine, The University of Melbourne, Parkville, VIC, Australia
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15
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Ruderman I, Smith ER, Toussaint ND, Hewitson TD, Holt SG. Longitudinal changes in bone and mineral metabolism after cessation of cinacalcet in dialysis patients with secondary hyperparathyroidism. BMC Nephrol 2018; 19:113. [PMID: 29764395 PMCID: PMC5952622 DOI: 10.1186/s12882-018-0910-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/27/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The calcimimetic agent cinacalcet is effective for the management of secondary hyperparathyroidism (SHPT) in dialysis patients. Changes to reimbursement of cinacalcet in Australia provided an opportunity to assess effects of medication cessation on biochemical and clinical outcomes in dialysis patients, including changes to novel biomarkers such as calciprotein particles (CPP). CPP are nanoparticles of mineral and protein in the circulation associated with increased vascular calcification in patients with chronic kidney disease. METHODS Dialysis patients from a single center who ceased cinacalcet between August 2015 and March 2016 were included in a prospective observational study. Bloods were taken at the time of cessation of cinacalcet and at 1, 6 and 12 months. Clinical and biochemical outcomes were compared with an age- and gender-matched cohort of cinacalcet-naïve dialysis patients. RESULTS Sixty-two patients participated in the study. Mean age was 69.6 ± 13.2 years. Biochemical changes over 12 months following cessation of cinacalcet included an increase in serum parathyroid hormone (PTH) (42.2 [IQR 27.8-94.6] pmol/L to 114.8 [83.9-159.1] pmol/L [p < 0.001]), serum calcium (2.31 ± 0.21 mmol/L to 2.46 ± 0.14 mmol/L [p < 0.001]) and primary CPP (CPP-I) (p = 0.002). Changes in CPP were associated with an increase in PTH (p = 0.007), calcium (p = 0.002) and ferritin (p = 0.02) but a reduction in serum albumin (p = 0.001). Over the 12-month period, there were two fractures, five cardiovascular events, one episode of calciphylaxis, and one parathyroidectomy, with a mortality rate of 19% (n = 13). CONCLUSION Uniquely we report the effects of cinacalcet withdrawal in a real world setting with demonstrated increases in PTH, serum calcium and CPP subsets, novel CKD-MBD related factors, over a 12-month period.
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Affiliation(s)
- Irene Ruderman
- Department of Nephrology, The Royal Melbourne Hospital, 300 Grattan St, Parkville, Victoria, 3050, Australia. .,Department of Medicine (RMH), The University of Melbourne, Melbourne, Victoria, Australia.
| | - Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, 300 Grattan St, Parkville, Victoria, 3050, Australia.,Department of Medicine (RMH), The University of Melbourne, Melbourne, Victoria, Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, 300 Grattan St, Parkville, Victoria, 3050, Australia.,Department of Medicine (RMH), The University of Melbourne, Melbourne, Victoria, Australia
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, 300 Grattan St, Parkville, Victoria, 3050, Australia.,Department of Medicine (RMH), The University of Melbourne, Melbourne, Victoria, Australia
| | - Stephen G Holt
- Department of Nephrology, The Royal Melbourne Hospital, 300 Grattan St, Parkville, Victoria, 3050, Australia.,Department of Medicine (RMH), The University of Melbourne, Melbourne, Victoria, Australia
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16
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Ruderman I, Holt SG, Hewitson TD, Smith ER, Toussaint ND. Current and potential therapeutic strategies for the management of vascular calcification in patients with chronic kidney disease including those on dialysis. Semin Dial 2018; 31:487-499. [PMID: 29733462 DOI: 10.1111/sdi.12710] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Patients with CKD have accelerated vascular stiffening contributing significantly to excess cardiovascular morbidity and mortality. Much of the arterial stiffening is thought to involve vascular calcification (VC), but the pathogenesis of this phenomenon is complex, resulting from a disruption of the balance between promoters and inhibitors of calcification in a uremic milieu, along with derangements in calcium and phosphate metabolic pathways. Management of traditional cardiovascular risk factors to reduce VC may be influential but has not been shown to significantly improve mortality. Control of mineral metabolism may potentially reduce the burden of VC, although using conventional approaches of restricting dietary phosphate, administering phosphate binders, and use of active vitamin D and calcimimetics, remains controversial because recommended biochemical targets are hard to achieve and clinical relevance hard to define. Increasing time on dialysis is perhaps another therapy with potential effectiveness in this area. Despite current treatments, cardiovascular morbidity and mortality remain high in this group. Novel therapies for addressing VC include magnesium and vitamin K supplementation, which are currently being investigated in large randomized control trials. Other therapeutic targets include crystallization inhibitors, ligand trap for activin receptors and BMP-7. This review summarizes current treatment strategies and therapeutic targets for the future management of VC in patients with CKD.
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Affiliation(s)
- Irene Ruderman
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine (RMH), The University of Melbourne, Melbourne, Vic., Australia
| | - Stephen G Holt
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine (RMH), The University of Melbourne, Melbourne, Vic., Australia
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine (RMH), The University of Melbourne, Melbourne, Vic., Australia
| | - Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine (RMH), The University of Melbourne, Melbourne, Vic., Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine (RMH), The University of Melbourne, Melbourne, Vic., Australia
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17
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Abstract
Calciprotein particles (CPP) have emerged as nanoscale mediators of phosphate-induced toxicity in Chronic Kidney Disease (CKD). Uraemia favors ripening of the particle mineral content from the amorphous (CPP-I) to the crystalline state (CPP-II) but the pathophysiological significance of this transformation is uncertain. Clinical studies suggest an association between CPP ripening and inflammation, vascular dysfunction and mortality. Although ripening has been modelled in vitro, it is unknown whether particles synthesised in serum resemble their in vivo counterparts. Here we show that in vitro formation and ripening of CPP in uraemic serum is characterised by extensive physiochemical rearrangements involving the accretion of mineral, loss of surface charge and transformation of the mineral phase from a spherical arrangement of diffuse domains of amorphous calcium phosphate to densely-packed lamellar aggregates of crystalline hydroxyapatite. These physiochemical changes were paralleled by enrichment with small soluble apolipoproteins, complement factors and the binding of fatty acids. In comparison, endogenous CPP represent a highly heterogeneous mixture of particles with characteristics mostly intermediate to synthetic CPP-I and CPP-II, but are also uniquely enriched for carbonate-substituted apatite, DNA fragments, small RNA and microbe-derived components. Pathway analysis of protein enrichment predicted the activation of cell death and pro-inflammatory processes by endogenous CPP and synthetic CPP-II alike. This comprehensive characterisation validates the use of CPP-II generated in uraemic serum as in vitro equivalents of their endogenous counterparts and provides insight into the nature and pathological significance of CPP in CKD, which may act as vehicles for various bioactive ligands.
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Affiliation(s)
- Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia; Department of Medicine - Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia.
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia; Department of Medicine - Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Eric Hanssen
- Melbourne Advanced Microscopy Facility and Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Australia
| | - Stephen G Holt
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia; Department of Medicine - Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia
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18
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Smith ER, Hewitson TD, Cai MMX, Aghagolzadeh P, Bachtler M, Pasch A, Holt SG. A novel fluorescent probe-based flow cytometric assay for mineral-containing nanoparticles in serum. Sci Rep 2017; 7:5686. [PMID: 28720774 PMCID: PMC5515983 DOI: 10.1038/s41598-017-05474-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/30/2017] [Indexed: 12/20/2022] Open
Abstract
Calciprotein particles, nanoscale aggregates of insoluble mineral and binding proteins, have emerged as potential mediators of phosphate toxicity in patients with Chronic Kidney Disease. Although existing immunochemical methods for their detection have provided compelling data, these approaches are indirect, lack specificity and are subject to a number of other technical and theoretical shortcomings. Here we have developed a rapid homogeneous fluorescent probe-based flow cytometric method for the detection and quantitation of individual mineral-containing nanoparticles in human and animal serum. This method allows the discrimination of membrane-bound from membrane-free particles and different mineral phases (amorphous vs. crystalline). Critically, the method has been optimised for use on a conventional instrument, without the need for manual hardware adjustments. Using this method, we demonstrate a consistency in findings across studies of Chronic Kidney Disease patients and commonly used uraemic animal models. These studies demonstrate that renal dysfunction is associated with the ripening of calciprotein particles to the crystalline state and reveal bone metabolism and dietary mineral as important modulators of circulating levels. Flow cytometric analysis of calciprotein particles may enhance our understanding of mineral handling in kidney disease and provide a novel indicator of therapeutic efficacy for interventions targeting Chronic Kidney Disease-Mineral Bone Disorder.
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Affiliation(s)
- Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia. .,Department of Medicine - Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia.
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia.,Department of Medicine - Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Michael M X Cai
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia.,Department of Medicine - Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | | | - Matthias Bachtler
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Andreas Pasch
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Stephen G Holt
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia.,Department of Medicine - Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia
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19
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Tan SJ, Smith ER, Holt SG, Hewitson TD, Toussaint ND. Soluble klotho may be a marker of phosphate reabsorption. Clin Kidney J 2017; 10:397-404. [PMID: 28616218 PMCID: PMC5466110 DOI: 10.1093/ckj/sfw146] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 12/05/2016] [Indexed: 12/20/2022] Open
Abstract
Background: Membrane-bound α-klotho functions as a co-receptor with fibroblast growth factor receptor at the renal tubule conferring specificity to fibroblast growth factor-23 (FGF-23), allowing it to inhibit tubular phosphate reabsorption at physiological concentrations. α-klotho also exists as a soluble protein. However, the complex interrelationships between soluble α-klotho (sKl), FGF-23 and phosphate reabsorption are poorly understood, with little known about the links between sKl, FGF-23 and phosphate reabsorption in chronic kidney disease (CKD). This study addresses this issue in a cohort of patients with and without CKD. Methods: We conducted a single-centre, cross-sectional study of contemporaneously obtained samples of blood and 24-h urine biochemistry along with sKl and intact FGF-23 (iFGF-23) from non-dialysis-dependent CKD patients and healthy volunteers. Pearson's correlation coefficients were used to determine correlations between natural log-transformed (Ln) sKl and iFGF-23 with other parameters of interest. Backward multivariate analysis was undertaken to evaluate the relationship between mineral parameters. Results: One hundred and sixteen participants (77 with CKD and 39 healthy volunteers) were studied, of which 74 (63.8%) were male. The median age was 61 (interquartile range 49-71) years. Those with CKD had lower sKl (408 versus 542 pg/mL), higher iFGF-23 (94 versus 41 pg/mL), higher fractional excretion of phosphate (25.05 versus 10.98%) and lower daily urinary phosphate excretion (UPE) (24.8 versus 32.3 mmol/L) compared with healthy volunteers (all P ≤ 0.002). Age correlated inversely and estimated glomerular filtration rate (eGFR) correlated positively with phosphate reabsorption and Ln(sKl), while the opposite was seen with Ln(iFGF23). Upon multivariate analysis, eGFR, Ln(sKl) and parathyroid hormone were independently associated with phosphate reabsorption, whereas Ln(iFGF-23) was not, after adjustment for age. Conclusions: Abnormalities in phosphate regulatory pathways are disturbed early in CKD. While iFGF-23 is associated with phosphate excretion on univariate analyses, sKl demonstrates a significant association with phosphate reabsorption independent of iFGF-23, and this relationship deserves further exploration.
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Affiliation(s)
- Sven-Jean Tan
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Melbourne, Australia
| | - Edward R. Smith
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Australia
| | - Stephen G. Holt
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Melbourne, Australia
| | - Tim D. Hewitson
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Melbourne, Australia
| | - Nigel D. Toussaint
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Melbourne, Australia
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Samuel CS, Royce SG, Hewitson TD, Denton KM, Cooney TE, Bennett RG. Anti-fibrotic actions of relaxin. Br J Pharmacol 2017; 174:962-976. [PMID: 27250825 PMCID: PMC5406285 DOI: 10.1111/bph.13529] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/19/2016] [Accepted: 05/23/2016] [Indexed: 12/19/2022] Open
Abstract
Fibrosis refers to the hardening or scarring of tissues that usually results from aberrant wound healing in response to organ injury, and its manifestations in various organs have collectively been estimated to contribute to around 45-50% of deaths in the Western world. Despite this, there is currently no effective cure for the tissue structural and functional damage induced by fibrosis-related disorders. Relaxin meets several criteria of an effective anti-fibrotic based on its specific ability to inhibit pro-fibrotic cytokine and/or growth factor-mediated, but not normal/unstimulated, fibroblast proliferation, differentiation and matrix production. Furthermore, relaxin augments matrix degradation through its ability to up-regulate the release and activation of various matrix-degrading matrix metalloproteinases and/or being able to down-regulate tissue inhibitor of metalloproteinase activity. Relaxin can also indirectly suppress fibrosis through its other well-known (anti-inflammatory, antioxidant, anti-hypertrophic, anti-apoptotic, angiogenic, wound healing and vasodilator) properties. This review will outline the organ-specific and general anti-fibrotic significance of exogenously administered relaxin and its mechanisms of action that have been documented in various non-reproductive organs such as the cardiovascular system, kidney, lung, liver, skin and tendons. In addition, it will outline the influence of sex on relaxin's anti-fibrotic actions, highlighting its potential as an emerging anti-fibrotic therapeutic. LINKED ARTICLES This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc.
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Affiliation(s)
- C S Samuel
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of PharmacologyMonash UniversityMelbourneVic.Australia
| | - S G Royce
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of PharmacologyMonash UniversityMelbourneVic.Australia
| | - T D Hewitson
- Department of NephrologyRoyal Melbourne HospitalMelbourneVic.Australia
| | - K M Denton
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of PhysiologyMonash UniversityMelbourneVic.Australia
| | - T E Cooney
- University of Pittsburgh Medical Centre (UPMC) HamotEriePAUSA
| | - R G Bennett
- Research Service 151VA Nebraska‐Western Iowa Health Care SystemOmahaNEUSA
- Department of Internal MedicineUniversity of Nebraska Medical CenterOmahaNEUSA
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Tan SJ, Hewitson TD, Hughes PD, Holt SG, Toussaint ND. Changes in Markers of Mineral Metabolism After Living Kidney Donation. Transplant Direct 2017; 3:e150. [PMID: 28405606 PMCID: PMC5381743 DOI: 10.1097/txd.0000000000000660] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 01/27/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Living kidney donors (LKDs) experience reduction in kidney function, however serum phosphate (sPi) levels are lower compared to patients with chronic kidney disease matched for reduced kidney function. Mineral metabolism adaptations that occur in LKDs have not been adequately investigated. To evaluate the effect of nephrectomy on markers of mineral metabolism in LKDs compared to healthy volunteers (HV) over 12 months. METHODS Mineral parameters were evaluated in twenty-one adult LKDs and twenty HVs. Parameters included sPi, intact parathyroid hormone, fibroblast growth factor-23 (FGF23), soluble Klotho (sKl) and urinary phosphate, measured prior to donation (T0), 1 month (T1), 6 months (T6) and 12 months (T12) post-kidney donation. Statistical analyses were conducted on normalized variables and changes were assessed using 2-way analysis of variance. RESULTS Mean ages of LKDs and HVs were 54.1 ± 14.7 and 52.6 ± 8.0 years, respectively. There were no baseline clinical or biochemical differences between LKDs and HVs. In LKDs at T1, serum creatinine increased (from 75 ± 12 to 114 ± 22 μmol/L), FGF23 increased (52 ± 15 to 70 ± 19 pg/mL) and sKl decreased (564 [469-662] to 424 [375-523] pg/mL), all P less than 0.001. Changes were sustained at T12. After donation, LKDs consistently demonstrated lower sPi compared with T0, with the maximal sPi change at T6 (-0.19 mmol/L difference, P < 0.001). Other markers of mineral metabolism were unchanged in LKDs. There were no mineral differences in HVs over 12 months. CONCLUSIONS Prospective evaluation of mineral metabolism parameters in LKDs provides valuable insight into compensatory mechanisms after reduction in kidney function. Further reduction of sPi at T6 despite early alterations in FGF23 and sKl suggest adaptation of mineral metabolism continues long-term in LKDs.
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Affiliation(s)
- Sven-Jean Tan
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
| | - Tim D. Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
| | - Peter D. Hughes
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
| | - Stephen G. Holt
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
| | - Nigel D. Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
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Tan SJ, Crosthwaite A, Langsford D, Obeysekere V, Ierino FL, Roberts MA, Hughes PD, Hewitson TD, Dwyer KM, Toussaint ND. Mineral adaptations following kidney transplantation. Transpl Int 2017; 30:463-473. [PMID: 28120476 DOI: 10.1111/tri.12925] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/28/2016] [Accepted: 01/18/2017] [Indexed: 12/30/2022]
Abstract
Klotho is predominantly expressed in the kidney and reported to have antioxidant and antifibrotic properties. Soluble Klotho (sKl), the circulating protein cleaved from membrane-bound Klotho, is reduced significantly with kidney disease and inversely associated with mortality. sKl has not been thoroughly evaluated prospectively after kidney transplantation. Incident kidney transplant recipients (KTRs) were prospectively evaluated pretransplantation, 1, 12 and 52 weeks post-transplantation. Basic biochemistry, sKl and intact FGF23 were measured. Within-subject comparisons were evaluated using repeat-measure anova or Friedman's analysis. Effects of immunosuppression and biochemical parameters on sKl and FGF-23 over time were analysed using mixed-effects modelling. Median serum creatinine (sCr) at 1 week was 116 (92-142) μmol/l, and at 52 weeks, all 29 KTRs had a functioning graft with median sCr of 111 (97-131) μmol/l. Compared with baseline, sKl was increased at 52 weeks following an initial decline at 1 week (P < 0.005 and P < 0.01, respectively), while FGF23 was considerably reduced at 52 weeks (P < 0.001). In a mixed-effects model, an increased sKl was not associated with reduction in immunosuppression or evaluated biochemical parameters. Modest increase in sKl is observed one-year postkidney transplantation with excellent early graft function suggesting factors beyond renal capacity may influence circulating sKl. FGF23 normalization was observed. Longer term evaluation in transplantation, specifically addressing the effects of immunosuppression, is required to understand the pathophysiology of the sKl/FGF23 axis and potential for modification.
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Affiliation(s)
- Sven-Jean Tan
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine, The University of Melbourne, Parkville, Vic., Australia
| | - Amy Crosthwaite
- Department of Medicine, The University of Melbourne, Parkville, Vic., Australia.,Department of Nephrology, Austin Hospital, Heidelberg, Vic., Australia
| | - David Langsford
- Department of Nephrology, Northern Hospital, Epping, Vic., Australia
| | - Varuni Obeysekere
- Department of Endocrinology, St Vincent's Hospital Melbourne, Fitzroy, Vic., Australia
| | - Frank L Ierino
- Department of Medicine, The University of Melbourne, Parkville, Vic., Australia.,Department of Nephrology, St Vincent's Hospital Melbourne, Fitzroy, Vic., Australia.,Victorian Kidney Transplantation Collaborative, Melbourne, Vic., Australia
| | - Matthew A Roberts
- Victorian Kidney Transplantation Collaborative, Melbourne, Vic., Australia.,Eastern Health Clinical School, Monash University, Box Hill, Vic., Australia
| | - Peter D Hughes
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine, The University of Melbourne, Parkville, Vic., Australia
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine, The University of Melbourne, Parkville, Vic., Australia
| | - Karen M Dwyer
- Department of Medicine, The University of Melbourne, Parkville, Vic., Australia.,Department of Nephrology, St Vincent's Hospital Melbourne, Fitzroy, Vic., Australia.,Victorian Kidney Transplantation Collaborative, Melbourne, Vic., Australia.,School of Medicine, Deakin University, Geelong, Vic., Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine, The University of Melbourne, Parkville, Vic., Australia
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Tan SJ, Satake S, Smith ER, Toussaint ND, Hewitson TD, Holt SG. Parenteral iron polymaltose changes i:c-terminal FGF23 ratios in iron deficiency, but not in dialysis patients. Eur J Clin Nutr 2016; 71:180-184. [DOI: 10.1038/ejcn.2016.217] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 09/22/2016] [Accepted: 09/27/2016] [Indexed: 12/17/2022]
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Hewitson TD, Boon WC, Simpson ER, Smith ER, Samuel CS. Estrogens do not protect, but androgens exacerbate, collagen accumulation in the female mouse kidney after ureteric obstruction. Life Sci 2016; 158:130-6. [PMID: 27373424 DOI: 10.1016/j.lfs.2016.06.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 06/24/2016] [Indexed: 11/18/2022]
Abstract
AIMS Controversy surrounds the gender basis of progression in chronic kidney disease. Unfortunately, most experimental studies addressing this question do not distinguish between direct effects of estrogen and indirect activation of estrogen receptors through conversion of testosterone to 17β-estradiol by aromatase. We examined the pathogenesis of renal fibrosis in female aromatase knockout (ArKO) mice, which lack circulating and stored estrogens, while having normal levels of testosterone. MAIN METHODS ArKO mice and their wild-type (ArWT) counterparts were subjected to unilateral ureteric obstruction (UUO), with kidney tissue collected at day(D) 0, 3 and 9 post-UUO. Effects of 5α-dihydrotestosterone (DHT) administration on each genotype were also studied. Tissue was assessed biochemically and histochemically for fibrosis. Western blot analysis was used to measure α-smooth muscle actin (α-SMA) expression and TGF-β1 signalling. Matrix metalloproteinase-2 (MMP-2) activity was measured by zymography. KEY FINDINGS UUO increased collagen content over time (p<0.05 (D3) and p<0.01 (D9) vs day 0), with no difference between genotypes in qualitative (collagen IV staining) and quantitative (hydroxyproline concentration) analyses. Systemic administration of non-aromatizable DHT increased collagen content after 3days of UUO in both genotypes. This was not paralleled by any change in α-SMA (myofibroblast burden) or TGF-β1 signalling but was commensurate with DHT reducing MMP2 activity in both genotypes (p<0.05 vs genotype controls). SIGNIFICANCE Physiological concentrations of estrogens do not protect the injured kidney from fibrosis progression. Androgens rather than estrogens are the relevant factor involved in regulating disease-related renal scarring in this model.
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Affiliation(s)
- Tim D Hewitson
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia; Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Carlton, Victoria, Australia
| | - Wah Chin Boon
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia; Prince Henry's Institute of Medical Research, Monash University, Clayton, Victoria, Australia.
| | - Evan R Simpson
- Prince Henry's Institute of Medical Research, Monash University, Clayton, Victoria, Australia
| | - Edward R Smith
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Chrishan S Samuel
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia; Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia.
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Tan SJ, Smith ER, Hewitson TD, Holt SG, Toussaint ND. The importance of klotho in phosphate metabolism and kidney disease. Nephrology (Carlton) 2016; 19:439-49. [PMID: 24750549 DOI: 10.1111/nep.12268] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2014] [Indexed: 12/19/2022]
Abstract
The discovery of fibroblast growth factor-23 (FGF23) and its co-receptor α-klotho has broadened our understanding of mineral metabolism and led to a renewed research focus on phosphate homeostatic pathways in kidney disease. Expanding knowledge of these mechanisms, both in normal physiology and in pathology, identifies targets for potential interventions designed to reduce the complications of renal disease, particularly the cardiovascular sequelae. FGF23 has emerged as a major α-klotho-dependent endocrine regulator of mineral metabolism, functioning to activate vitamin D and as a phosphatonin. However, increasingly there is an appreciation that klotho may act independently as a phosphate regulator, as well as having significant activity in other key biological processes. This review outlines our current understanding of klotho, and its potential contribution to kidney disease and cardiovascular health.
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Affiliation(s)
- Sven-Jean Tan
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia; Department of Medicine (RMH), The University of Melbourne, Melbourne, Victoria, Australia
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Wang C, Kemp-Harper BK, Kocan M, Ang SY, Hewitson TD, Samuel CS. The Anti-fibrotic Actions of Relaxin Are Mediated Through a NO-sGC-cGMP-Dependent Pathway in Renal Myofibroblasts In Vitro and Enhanced by the NO Donor, Diethylamine NONOate. Front Pharmacol 2016; 7:91. [PMID: 27065874 PMCID: PMC4815292 DOI: 10.3389/fphar.2016.00091] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 03/21/2016] [Indexed: 01/08/2023] Open
Abstract
INTRODUCTION The anti-fibrotic hormone, relaxin, has been inferred to disrupt transforming growth factor (TGF)-β1/Smad2 phosphorylation (pSmad2) signal transduction and promote collagen-degrading gelatinase activity via a nitric oxide (NO)-dependent pathway. Here, we determined the extent to which NO, soluble guanylate cyclase (sGC) and cyclic guanosine monophosphate (cGMP) were directly involved in the anti-fibrotic actions of relaxin using a selective NO scavenger and sGC inhibitor, and comparing and combining relaxin's effects with that of an NO donor. METHODS AND RESULTS Primary renal cortical myofibroblasts isolated from injured rat kidneys were treated with human recombinant relaxin (RLX; 16.8 nM), the NO donor, diethylamine NONOate (DEA/NO; 0.5-5 μM) or the combined effects of RLX (16.8 nM) and DEA/NO (5 μM) over 72 h. The effects of RLX (16.8 nM) and DEA/NO (5 μM) were also evaluated in the presence of the NO scavenger, hydroxocobalamin (HXC; 100 μM) or sGC inhibitor, ODQ (5 μM) over 72 h. Furthermore, the effects of RLX (30 nM), DEA/NO (5 μM) and RLX (30 nM) + DEA/NO (5 μM) on cGMP levels were directly measured, in the presence or absence of ODQ (5 μM). Changes in matrix metalloproteinase (MMP)-2, MMP-9 (cell media), pSmad2 and α-smooth muscle actin (α-SMA; a measure myofibroblast differentiation) (cell layer) were assessed by gelatin zymography and Western blotting, respectively. At the highest concentration tested, both RLX and DEA/NO promoted MMP-2 and MMP-9 levels by 25-33%, while inhibiting pSmad2 and α-SMA expression by up to 50% (all p < 0.05 vs. untreated and vehicle-treated cells). However, 5μM of DEA/NO was required to produce the effects seen with 16.8 nM of RLX over 72 h. The anti-fibrotic effects of RLX or DEA/NO alone were completely abrogated by HXC and ODQ (both p < 0.01 vs. RLX alone or DEA/NO alone), but were significantly enhanced when added in combination (all p < 0.05 vs. RLX alone). Additionally, the direct cGMP-promoting effects of RLX, DEA/NO and RLX+DEA/NO (which all increased cGMP levels by 12-16-fold over basal levels; all p < 0.01 vs. vehicle-treated cells) were significantly inhibited by pre-treatment of ODQ (all p < 0.05 vs. the respective treatments alone). CONCLUSION These findings confirmed that RLX mediates its TGF-β1-inhibitory and gelatinase-promoting effects via a NO-sGC-cGMP-dependent pathway, which was additively augmented by co-administration of DEA/NO.
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Affiliation(s)
- Chao Wang
- Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University Clayton, VIC, Australia
| | - Barbara K Kemp-Harper
- Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University Clayton, VIC, Australia
| | - Martina Kocan
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville VIC, Australia
| | - Sheng Yu Ang
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville VIC, Australia
| | - Tim D Hewitson
- Department of Nephrology, Royal Melbourne Hospital, ParkvilleVIC, Australia; Department of Medicine, Royal Melbourne Hospital, University of MelbourneParkville, VIC, Australia
| | - Chrishan S Samuel
- Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University Clayton, VIC, Australia
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Hewitson TD, Holt SG, Smith ER. Animal Models to Study Links between Cardiovascular Disease and Renal Failure and Their Relevance to Human Pathology. Front Immunol 2015; 6:465. [PMID: 26441970 PMCID: PMC4585255 DOI: 10.3389/fimmu.2015.00465] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/26/2015] [Indexed: 12/24/2022] Open
Abstract
The close association between cardiovascular pathology and renal dysfunction is well documented and significant. Patients with conventional risk factors for cardiovascular disease like diabetes and hypertension also suffer renal dysfunction. This is unsurprising if the kidney is simply regarded as a “modified blood vessel” and thus, traditional risk factors will affect both systems. Consistent with this, it is relatively easy to comprehend how patients with either sudden or gradual cardiac and or vascular compromise have changes in both renal hemodynamic and regulatory systems. However, patients with pure or primary renal dysfunction also have metabolic changes (e.g., oxidant stress, inflammation, nitric oxide, or endocrine changes) that affect the cardiovascular system. Thus, cardiovascular and renal systems are intimately, bidirectionally and inextricably linked. Whilst we understand several of these links, some of the mechanisms for these connections remain incompletely explained. Animal models of cardiovascular and renal disease allow us to explore such mechanisms, and more importantly, potential therapeutic strategies. In this article, we review various experimental models used, and examine critically how representative they are of the human condition.
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Affiliation(s)
- Tim D Hewitson
- Department of Nephrology, Royal Melbourne Hospital (RMH) , Melbourne, VIC , Australia ; Department of Medicine - RMH, University of Melbourne , Melbourne, VIC , Australia
| | - Stephen G Holt
- Department of Nephrology, Royal Melbourne Hospital (RMH) , Melbourne, VIC , Australia ; Department of Medicine - RMH, University of Melbourne , Melbourne, VIC , Australia
| | - Edward R Smith
- Department of Nephrology, Royal Melbourne Hospital (RMH) , Melbourne, VIC , Australia
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Krishnan SM, Dowling JK, Ling YH, Diep H, Chan CT, Ferens D, Kett MM, Pinar A, Samuel CS, Vinh A, Arumugam TV, Hewitson TD, Kemp-Harper BK, Robertson AAB, Cooper MA, Latz E, Mansell A, Sobey CG, Drummond GR. Inflammasome activity is essential for one kidney/deoxycorticosterone acetate/salt-induced hypertension in mice. Br J Pharmacol 2015; 173:752-65. [PMID: 26103560 DOI: 10.1111/bph.13230] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 05/16/2015] [Accepted: 06/13/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE Inflammasomes are multimeric complexes that facilitate caspase-1-mediated processing of the pro-inflammatory cytokines IL-1β and IL-18. Clinical hypertension is associated with renal inflammation and elevated circulating levels of IL-1β and IL-18. Therefore, we investigated whether hypertension in mice is associated with increased expression and/or activation of the inflammasome in the kidney, and if inhibition of inflammasome activity reduces BP, markers of renal inflammation and fibrosis. EXPERIMENTAL APPROACH Wild-type and inflammasome-deficient ASC(-/-) mice were uninephrectomized and received deoxycorticosterone acetate and saline to drink (1K/DOCA/salt). Control mice were uninephrectomized but received a placebo pellet and water. BP was measured by tail cuff; renal expression of inflammasome subunits and inflammatory markers was measured by real-time PCR and immunoblotting; macrophage and collagen accumulation was assessed by immunohistochemistry. KEY RESULTS 1K/DOCA/salt-induced hypertension in mice was associated with increased renal mRNA expression of inflammasome subunits NLRP3, ASC and pro-caspase-1, and the cytokine, pro-IL-1β, as well as protein levels of active caspase-1 and mature IL-1β. Following treatment with 1K/DOCA/salt, ASC(-/-) mice displayed blunted pressor responses and were also protected from increases in renal expression of IL-6, IL-17A, CCL2, ICAM-1 and VCAM-1, and accumulation of macrophages and collagen. Finally, treatment with a novel inflammasome inhibitor, MCC950, reversed hypertension in 1K/DOCA/salt-treated mice. CONCLUSIONS AND IMPLICATIONS Renal inflammation, fibrosis and elevated BP induced by 1K/DOCA/salt treatment are dependent on inflammasome activity, highlighting the inflammasome/IL-1β pathway as a potential therapeutic target in hypertension.
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Affiliation(s)
- S M Krishnan
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - J K Dowling
- Centre for Innate Immunity and Infectious Diseases, MIMR-PHI Institute of Medical Research, Clayton, Vic., Australia
| | - Y H Ling
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - H Diep
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - C T Chan
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - D Ferens
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - M M Kett
- Department of Physiology, Monash University, Clayton, Vic., Australia
| | - A Pinar
- Centre for Innate Immunity and Infectious Diseases, MIMR-PHI Institute of Medical Research, Clayton, Vic., Australia
| | - C S Samuel
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - A Vinh
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - T V Arumugam
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - T D Hewitson
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Vic., Australia
| | - B K Kemp-Harper
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - A A B Robertson
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - M A Cooper
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - E Latz
- Institute of Innate Immunity, University Hospital, University of Bonn, Bonn, Germany.,Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, USA.,German Center for Neurodegenerative Diseases, Bonn, Germany
| | - A Mansell
- Centre for Innate Immunity and Infectious Diseases, MIMR-PHI Institute of Medical Research, Clayton, Vic., Australia
| | - C G Sobey
- Department of Pharmacology, Monash University, Clayton, Vic., Australia.,Department of Surgery, Monash Medical Centre, Southern Clinical School, Monash University, Clayton, Vic., Australia
| | - G R Drummond
- Department of Pharmacology, Monash University, Clayton, Vic., Australia.,Department of Surgery, Monash Medical Centre, Southern Clinical School, Monash University, Clayton, Vic., Australia
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Smith ER, Hewitson TD, Hanssen E, Pasch A, Holt SG. SP397FETUIN-A ATTENUATES MINERAL NANOPARTICLE ACTIVATION OF THE NLRP3 INFLAMMASOME IN THE HUMAN MACROPHAGE. Nephrol Dial Transplant 2015. [DOI: 10.1093/ndt/gfv193.05] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Smith E, Hewitson TD, Kelynack K, Hanssen E, Pasch A, Holt SG. SaO024CALCIPROTEIN PARTICLE RIPENING INDUCES RUNX2-INDEPENDENT MINERALISATION OF HUMAN AORTIC VASCULAR SMOOTH MUSCLE CELLS. Nephrol Dial Transplant 2015. [DOI: 10.1093/ndt/gfv150.01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Tan SJ, Smith ER, Hewitson TD, Holt SG, Toussaint ND. Diurnal variation and short-term pre-analytical stability of serum soluble α-klotho in healthy volunteers: a pilot study. Ann Clin Biochem 2014; 52:506-9. [PMID: 25416731 DOI: 10.1177/0004563214563415] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2014] [Indexed: 11/16/2022]
Abstract
AIM To investigate the diurnal variability and pre-analytical stability of soluble α-klotho in serum. BACKGROUND Recent evidence suggests that the cleaved extracellular domain of the α-klotho receptor, soluble α-klotho, affects phosphate homeostasis, ion channel regulation and antifibrotic/antioxidant pathways. However, soluble α-klotho measurements have yielded inconsistent results when related to renal function, markers of mineral metabolism and patient outcomes. Pre-analytical factors such as biological variation and analyte stability may affect the interpretation of soluble α-klotho results but are yet to be formally assessed. METHODS Clotted blood samples were collected from 10 healthy adult volunteers at three time-points during the day to assess diurnal change. Additional samples were collected and allowed to stand at room temperature for 30, 60 and 120 min, prior to centrifugation and analysis to evaluate analyte stability. Serum soluble α-klotho was measured using a validated commercial enzyme-linked immunosorbent assay. RESULTS Delayed processing of samples had no significant effect on serum soluble α-klotho concentrations over a 2-h period. Serum soluble α-klotho concentrations remained stable over morning, midday and afternoon time-points in this pilot study. CONCLUSION Serum soluble α-klotho demonstrates short-term pre-analytical stability and minimal diurnal variability in this pilot study. Larger studies are warranted to confirm these findings.
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Affiliation(s)
- Sven-Jean Tan
- Department of Nephrology, The Royal Melbourne Hospital (RMH), Parkville, Australia Department of Medicine (RMH), The University of Melbourne, Melbourne, Australia
| | - Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital (RMH), Parkville, Australia
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital (RMH), Parkville, Australia Department of Medicine (RMH), The University of Melbourne, Melbourne, Australia
| | - Stephen G Holt
- Department of Nephrology, The Royal Melbourne Hospital (RMH), Parkville, Australia Department of Medicine (RMH), The University of Melbourne, Melbourne, Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital (RMH), Parkville, Australia Department of Medicine (RMH), The University of Melbourne, Melbourne, Australia
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Otvos L, Knappe D, Hoffmann R, Kovalszky I, Olah J, Hewitson TD, Stawikowska R, Stawikowski M, Cudic P, Lin F, Wade JD, Surmacz E, Lovas S. Development of second generation peptides modulating cellular adiponectin receptor responses. Front Chem 2014; 2:93. [PMID: 25368867 PMCID: PMC4201147 DOI: 10.3389/fchem.2014.00093] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 10/01/2014] [Indexed: 01/16/2023] Open
Abstract
The adipose tissue participates in the regulation of energy homeostasis as an important endocrine organ that secretes a number of biologically active adipokines, including adiponectin. Recently we developed and characterized a first-in-class peptide-based adiponectin receptor agonist by using in vitro and in vivo models of glioblastoma and breast cancer (BC). In the current study, we further explored the effects of peptide ADP355 in additional cellular models and found that ADP355 inhibited chronic myeloid leukemia (CML) cell proliferation and renal myofibroblast differentiation with mid-nanomolar IC50 values. According to molecular modeling calculations, ADP355 was remarkably flexible in the global minimum with a turn present in the middle of the peptide. Considering these structural features of ADP355 and the fact that adiponectin normally circulates as multimeric complexes, we developed and tested the activity of a linear branched dimer (ADP399). The dimer exhibited approximately 20-fold improved cellular activity inhibiting K562 CML and MCF-7 cell growth with high pM-low nM relative IC50 values. Biodistribution studies suggested superior tissue dissemination of both peptides after subcutaneous administration relative to intraperitoneal inoculation. After screening of a 397-member adiponectin active site library, a novel octapeptide (ADP400) was designed that counteracted 10-1000 nM ADP355- and ADP399-mediated effects on CML and BC cell growth at nanomolar concentrations. ADP400 induced mitogenic effects in MCF-7 BC cells perhaps due to antagonizing endogenous adiponectin actions or acting as an inverse agonist. While the linear dimer agonist ADP399 meets pharmacological criteria of a contemporary peptide drug lead, the peptide showing antagonist activity (ADP400) at similar concentrations will be an important target validation tool to study adiponectin functions.
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Affiliation(s)
- Laszlo Otvos
- Department of Biology, Temple University Philadelphia, PA, USA
| | - Daniel Knappe
- Faculty of Chemistry and Mineralogy, Center for Biotechnology and Biomedicine, Institute of Bioanalytical Chemistry, Universität Leipzig Leipzig, Germany
| | - Ralf Hoffmann
- Faculty of Chemistry and Mineralogy, Center for Biotechnology and Biomedicine, Institute of Bioanalytical Chemistry, Universität Leipzig Leipzig, Germany
| | - Ilona Kovalszky
- 1st Institute of Pathology and Experimental Cancer Research, Faculty of Medicine, Semmelweis University Budapest, Hungary
| | - Julia Olah
- 1st Institute of Pathology and Experimental Cancer Research, Faculty of Medicine, Semmelweis University Budapest, Hungary
| | - Tim D Hewitson
- Department of Medicine, The University of Melbourne Melbourne, VIC, Australia
| | - Roma Stawikowska
- Torrey Pines Institute for Molecular Studies Port St. Lucie, Florida, FL, USA
| | - Maciej Stawikowski
- Torrey Pines Institute for Molecular Studies Port St. Lucie, Florida, FL, USA
| | - Predrag Cudic
- Torrey Pines Institute for Molecular Studies Port St. Lucie, Florida, FL, USA
| | - Feng Lin
- Florey Institute of Neuroscience and Mental Health and School of Chemistry, The University of Melbourne Melbourne, VIC, Australia
| | - John D Wade
- Florey Institute of Neuroscience and Mental Health and School of Chemistry, The University of Melbourne Melbourne, VIC, Australia
| | - Eva Surmacz
- Sbarro Institute for Cancer Research and Molecular Medicine, Temple University Philadelphia, PA, USA
| | - Sandor Lovas
- Department of Biomedical Sciences, Creighton University NE, USA
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Hewitson TD, Smith ER, Samuel CS. Qualitative and quantitative analysis of fibrosis in the kidney. Nephrology (Carlton) 2014; 19:721-6. [DOI: 10.1111/nep.12321] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Tim D. Hewitson
- Department of Nephrology; Royal Melbourne Hospital (RMH); Melbourne Victoria Australia
- Department of Medicine; Royal Melbourne Hospital (RMH); Melbourne Victoria Australia
| | - Edward R. Smith
- Department of Nephrology; Royal Melbourne Hospital (RMH); Melbourne Victoria Australia
| | - Chrishan S. Samuel
- Department of Pharmacology; Monash University; Melbourne Victoria Australia
- Florey Institute of Neuroscience and Mental Health; The University of Melbourne; Melbourne Victoria Australia
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Samuel CS, Bodaragama H, Chew JY, Widdop RE, Royce SG, Hewitson TD. Serelaxin Is a More Efficacious Antifibrotic Than Enalapril in an Experimental Model of Heart Disease. Hypertension 2014; 64:315-22. [DOI: 10.1161/hypertensionaha.114.03594] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Chrishan S. Samuel
- From the Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (C.S.S., H.B., J.Y.C., R.E.W., S.G.R.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health (C.S.S.) and Department of Biochemistry and Molecular Biology (C.S.S.), University of Melbourne, Melbourne, Victoria, Australia; Department of Nephrology, Royal Melbourne Hospital, Melbourne, Victoria, Australia (T.D.H.); and Department of Medicine, University of Melbourne, Royal Melbourne Hospital,
| | - Hasangika Bodaragama
- From the Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (C.S.S., H.B., J.Y.C., R.E.W., S.G.R.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health (C.S.S.) and Department of Biochemistry and Molecular Biology (C.S.S.), University of Melbourne, Melbourne, Victoria, Australia; Department of Nephrology, Royal Melbourne Hospital, Melbourne, Victoria, Australia (T.D.H.); and Department of Medicine, University of Melbourne, Royal Melbourne Hospital,
| | - Jacqueline Y. Chew
- From the Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (C.S.S., H.B., J.Y.C., R.E.W., S.G.R.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health (C.S.S.) and Department of Biochemistry and Molecular Biology (C.S.S.), University of Melbourne, Melbourne, Victoria, Australia; Department of Nephrology, Royal Melbourne Hospital, Melbourne, Victoria, Australia (T.D.H.); and Department of Medicine, University of Melbourne, Royal Melbourne Hospital,
| | - Robert E. Widdop
- From the Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (C.S.S., H.B., J.Y.C., R.E.W., S.G.R.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health (C.S.S.) and Department of Biochemistry and Molecular Biology (C.S.S.), University of Melbourne, Melbourne, Victoria, Australia; Department of Nephrology, Royal Melbourne Hospital, Melbourne, Victoria, Australia (T.D.H.); and Department of Medicine, University of Melbourne, Royal Melbourne Hospital,
| | - Simon G. Royce
- From the Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (C.S.S., H.B., J.Y.C., R.E.W., S.G.R.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health (C.S.S.) and Department of Biochemistry and Molecular Biology (C.S.S.), University of Melbourne, Melbourne, Victoria, Australia; Department of Nephrology, Royal Melbourne Hospital, Melbourne, Victoria, Australia (T.D.H.); and Department of Medicine, University of Melbourne, Royal Melbourne Hospital,
| | - Tim D. Hewitson
- From the Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (C.S.S., H.B., J.Y.C., R.E.W., S.G.R.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health (C.S.S.) and Department of Biochemistry and Molecular Biology (C.S.S.), University of Melbourne, Melbourne, Victoria, Australia; Department of Nephrology, Royal Melbourne Hospital, Melbourne, Victoria, Australia (T.D.H.); and Department of Medicine, University of Melbourne, Royal Melbourne Hospital,
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Chow BSM, Kocan M, Bosnyak S, Sarwar M, Wigg B, Jones ES, Widdop RE, Summers RJ, Bathgate RA, Hewitson TD, Samuel CS. Relaxin requires the angiotensin II type 2 receptor to abrogate renal interstitial fibrosis. Kidney Int 2014; 86:75-85. [DOI: 10.1038/ki.2013.518] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 09/23/2013] [Accepted: 10/17/2013] [Indexed: 02/06/2023]
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Wong SE, Samuel CS, Kelly DJ, Zhang Y, Becker GJ, Hewitson TD. The anti-fibrotic hormone relaxin is not reno-protective, despite being active, in an experimental model of type 1 diabetes. Protein Pept Lett 2014; 20:1029-38. [PMID: 23343143 DOI: 10.2174/0929866511320090009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 01/04/2013] [Accepted: 01/06/2013] [Indexed: 11/22/2022]
Abstract
The end-point of diabetic renal disease is the accumulation of excess collagen (fibrosis/sclerosis). A number of studies have shown that the hormone relaxin (RLX) ameliorates progression of renal and non-renal fibrosis. This study assessed the anti-fibrotic potential of RLX in streptozotocin (STZ)-treated transgenic mRen-2 rats, an accelerated model of type 1 diabetes. Eight-week old hyperglycaemic (STZ-treated at week-6) and normoglycaemic (STZ-untreated) animals were treated with or without recombinant human gene-2 (H2) RLX for 4-weeks (by osmotic mini-pumps) and assessed for various parameters at 12-weeks of age. Hyperglycaemic mRen-2 rats had elevated kidney weight/body weight ratio, glomerular filtration rate (GFR), albumin excretion rate (AER), interstitial collagen I and glomerulosclerosis (all p<0.05 vs non-diabetic controls). H2 RLX infusion had no effect on any of these parameters. Increased MMP-2 levels in RLX-treated rats demonstrated that the hormone was administered and active in this model. The inability of H2 RLX to slow glomerulopathy in diabetic mRen-2 rats could be in part due to the absence of its receptor, RXFP1, in rat mesangial cells, a primary mediator of diabetic glomerulosclerosis and/or the lack of any effect on TGF-β1/Smad2 signalling, a well described mediator of RLX activity. These findings highlight the cell specific actions of RLX, the dissociation of anti-fibrogenic (collagen synthesis) and antifibrolytic (MMP mediated collagen degradation) properties, and the central involvement of TGF-β1 in its actions.
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Affiliation(s)
- Su Ee Wong
- Howard Florey Institute, University of Melbourne, Victoria 3010, Australia
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Abstract
Over the past few decades, research on the peptide hormone, relaxin, has significantly improved our understanding of its biological actions under physiological and diseased conditions. This has facilitated the conducting of clinical trials to explore the use of serelaxin (human recombinant relaxin). Acute heart failure (AHF) is a very difficult to treat clinical entity, with limited success so far in developing new drugs to combat it. A recent phase-III RELAX-AHF trial using serelaxin therapy given during hospitalization revealed acute (ameliorated dyspnea) and chronic (improved 180-day survival) effects. Although these findings support a substantial improvement by serelaxin therapy over currently available therapies for AHF, they also raise key questions and stimulate new hypotheses. To facilitate the development of serelaxin as a new drug for heart disease, joint efforts of clinicians, research scientists and pharmacological industries are necessary to study these questions and hypotheses. In this review, after providing a brief summary of clinical findings and the pathophysiology of AHF, we present a working hypothesis of the mechanisms responsible for the observed efficacy of serelaxin in AHF patients. The existing clinical and preclinical data supporting our hypotheses are summarized and discussed. The development of serelaxin as a drug provides an excellent example of the bilateral nature of translational research.
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Affiliation(s)
- Xiao-Jun Du
- Baker IDI Heart and Diabetes Institute, Monash University
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Abstract
Animal models of chronic kidney disease (CKD) approximate the human condition and are keys to understanding its pathogenesis and to developing rational treatment strategies. The ethical use of animals requires a detailed understanding of the strengths and limitations of each species and the disease model, and the way in which findings can be translated from animals to humans. While not perfect, the careful use of animal experiments offers the opportunity to examine individual mechanisms in an accelerated time frame.
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Affiliation(s)
- Gavin J Becker
- Department of Nephrology, The Royal Melbourne Hospital and Department of Medicine, University of Melbourne, Melbourne, Vic, Australia
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Chow BSM, Chew EGY, Zhao C, Bathgate RAD, Hewitson TD, Samuel CS. Relaxin signals through a RXFP1-pERK-nNOS-NO-cGMP-dependent pathway to up-regulate matrix metalloproteinases: the additional involvement of iNOS. PLoS One 2012; 7:e42714. [PMID: 22936987 PMCID: PMC3425563 DOI: 10.1371/journal.pone.0042714] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Accepted: 07/11/2012] [Indexed: 02/06/2023] Open
Abstract
The hormone, relaxin, inhibits aberrant myofibroblast differentiation and collagen deposition by disrupting the TGF-β1/Smad2 axis, via its cognate receptor, Relaxin Family Peptide Receptor 1 (RXFP1), extracellular signal-regulated kinase (ERK)1/2 phosphorylation (pERK) and a neuronal nitric oxide (NO) synthase (nNOS)-NO-cyclic guanosine monophosphate (cGMP)-dependent pathway. However, the signalling pathways involved in its additional ability to increase matrix metalloproteinase (MMP) expression and activity remain unknown. This study investigated the extent to which the NO pathway was involved in human gene-2 (H2) relaxin's ability to positively regulate MMP-1 and its rodent orthologue, MMP-13, MMP-2 and MMP-9 (the main collagen-degrading MMPs) in TGF-β1-stimulated human dermal fibroblasts and primary renal myofibroblasts isolated from injured rats; by gelatin zymography (media) and Western blotting (cell layer). H2 relaxin (10-100 ng/ml) significantly increased MMP-1 (by ~50%), MMP-2 (by ~80%) and MMP-9 (by ~80%) in TGF-β1-stimulated human dermal fibroblasts; and MMP-13 (by ~90%), MMP-2 (by ~130%) and MMP-9 (by ~115%) in rat renal myofibroblasts (all p<0.01 vs untreated cells) over 72 hours. The relaxin-induced up-regulation of these MMPs, however, was significantly blocked by a non-selective NOS inhibitor (L-nitroarginine methyl ester (hydrochloride); L-NAME; 75-100 µM), and specific inhibitors to nNOS (N-propyl-L-arginine; NPLA; 0.2-2 µM), iNOS (1400W; 0.5-1 µM) and guanylyl cyclase (ODQ; 5 µM) (all p<0.05 vs H2 relaxin alone), but not eNOS (L-N-(1-iminoethyl)ornithine dihydrochloride; L-NIO; 0.5-5 µM). However, neither of these inhibitors affected basal MMP expression at the concentrations used. Furthermore, of the NOS isoforms expressed in renal myofibroblasts (nNOS and iNOS), H2 relaxin only stimulated nNOS expression, which in turn, was blocked by the ERK1/2 inhibitor (PD98059; 1 µM). These findings demonstrated that H2 relaxin signals through a RXFP1-pERK-nNOS-NO-cGMP-dependent pathway to mediate its anti-fibrotic actions, and additionally signals through iNOS to up-regulate MMPs; the latter being suppressed by TGF-β1 in myofibroblasts, but released upon H2 relaxin-induced inhibition of the TGF-β1/Smad2 axis.
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Affiliation(s)
- Bryna Suet Man Chow
- Florey Neuroscience Institutes, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Elaine Guo Yan Chew
- Florey Neuroscience Institutes, University of Melbourne, Parkville, Victoria, Australia
| | - Chongxin Zhao
- Florey Neuroscience Institutes, University of Melbourne, Parkville, Victoria, Australia
| | - Ross A. D. Bathgate
- Florey Neuroscience Institutes, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Tim D. Hewitson
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia
- Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Chrishan S. Samuel
- Florey Neuroscience Institutes, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia
- Department of Pharmacology, Monash University, Clayton, Victoria, Australia
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Abstract
Fibrotic disorders are commonplace, take many forms and can be life-threatening. No better example of this exists than the progressive fibrosis that accompanies all chronic renal disease. Renal fibrosis is a direct consequence of the kidney's limited capacity to regenerate after injury. Renal scarring results in a progressive loss of renal function, ultimately leading to end-stage renal failure and a requirement for dialysis or kidney transplantation. Although it manifests itself histologically as an increase in extracellular matrix, we know that the histological appearance can be caused by a de novo synthesis of matrix (primarily collagen), or a disproportionate loss of renal parenchyma. In both cases the process depends on a resident mesenchymal cell, the so-called myofibroblast, and is independent of disease etiology. Potentially we can ameliorate fibrosis, either indirectly by modifying the environment the kidney functions in, or more directly by interfering with activation and function of myofibroblasts. However, while renal fibrosis shares many features in common with the wound healing response in other organs, we also recognise that the consequences can be highly kidney specific. This review highlights the similarities and differences between this process in the kidney and other organs, and considers the therapeutic implications.
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Affiliation(s)
- Tim D Hewitson
- Department of Nephrology, Royal Melbourne Hospital & Department of Medicine, University of Melbourne, Melbourne, Australia
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Hewitson TD, Becker GJ. Glomerular density and progression. Nephrol Dial Transplant 2012; 27:2131-2; author reply 2132. [PMID: 22547752 DOI: 10.1093/ndt/gfs009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Hewitson TD, Zhao C, Wigg B, Lee SW, Simpson ER, Boon WC, Samuel CS. Relaxin and castration in male mice protect from, but testosterone exacerbates, age-related cardiac and renal fibrosis, whereas estrogens are an independent determinant of organ size. Endocrinology 2012; 153:188-99. [PMID: 22028442 DOI: 10.1210/en.2011-1311] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This study determined the effects of castration and hormone replacement therapy on the age-related cardiac and renal pathology of male relaxin gene-knockout (RlnKO) and age-matched wild-type (RlnWT) mice and that of aged male aromatase knockout (ArKO) mice, which lack estrogens and have 5-10 times the androgen levels of male wild-type mice. One-month-old RlnWT and RlnKO mice were bilaterally gonadectomized or sham operated and maintained until 12 months. Subgroups of castrated animals received testosterone or 17β-estradiol treatment from 9 to 12 months. Male ArKO mice and aromatase wild-type mice were aged to 12 months. Collected heart and kidney tissues were assessed for changes in organ size and fibrosis. Castration reduced body, heart, left ventricle, and kidney weights in both RlnKO and RlnWT mice, and the cardiac/renal fibrosis that was seen in sham RlnKO animals (all P < 0.05 vs. respective sham). Testosterone normalized organ weights and organ weight to body weight ratio of castrated animals and increased cardiac/renal collagen concentration to levels measured in or beyond that of sham RlnKO mice (all P < 0.05 vs. respective castrated mice). Furthermore, expression of TGF-β1, mothers against decapentaplegic homolog 2 (Smad2), and myofibroblast differentiation paralleled the above changes (all P < 0.05 vs. respective castrated mice), whereas matrix metalloproteinase-13 was decreased in testosterone-treated RlnKO mice. Conversely, 17β-estradiol only restored changes in organ size. Consistent with these findings, intact ArKO mice demonstrated increased cardiac/renal fibrosis in the absence of changes in organ size. These findings suggest that relaxin and castration protect, whereas androgens exacerbate, cardiac and renal fibrosis during ageing, whereas estrogens, in synergy with relaxin, regulates age-related changes in organ size.
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Affiliation(s)
- Tim D Hewitson
- Howard Florey Institute, University of Melbourne, Parkville, Victoria 3010, Australia
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Lian M, Hewitson TD, Wigg B, Samuel CS, Chow F, Becker GJ. Long-term mineralocorticoid receptor blockade ameliorates progression of experimental diabetic renal disease. Nephrol Dial Transplant 2011; 27:906-12. [PMID: 21908416 DOI: 10.1093/ndt/gfr495] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The final end point of diabetic renal disease is the accumulation of excess collagen. A number of studies have shown that aldosterone antagonism ameliorates progression of renal fibrosis. This study was designed to examine the effect of the mineralocorticoid receptor blocker eplerenone (EPL) on progression in streptozotocin (STZ)-treated spontaneously hypertensive rats (SHR), an accelerated model of Type I diabetes. STZ-treated SHRs with a blood glucose >18 mmol/L were randomly divided into treatment (100 mg/kg/day EPL) and non-treatment groups. Sham-injected SHR animals were used as a control. Functional parameters were monitored for 16 weeks, with structural parameters assessed at completion. Both hyperglycaemic groups developed progressive albuminuria, but the increase was ameliorated by EPL from Week 12. STZ-SHRs had elevated kidney weight/body weight ratio, glomerular size, glomerular macrophages (ED-1-positive cells), tissue transforming growth factor beta 1 (TGFβ1) concentrations and glomerular collagen IV staining (all P < 0.05 versus control animals). EPL reduced glomerular volume, TGFβ1 expression and glomerular collagen IV without changing glomerular macrophage infiltration. The ability of EPL to ameliorate these functional and structural changes in hyperglycaemic SHRs suggest that EPL has a renoprotective role in diabetic renal disease.
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Affiliation(s)
- Michael Lian
- Department of Nephrology, The Royal Melbourne Hospital, University of Melbourne, Melbourne, Australia
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Selvarajah M, Nicholls K, Hewitson TD, Becker GJ. Targeted urine microscopy in Anderson-Fabry disease: a cheap, sensitive and specific diagnostic technique. Nephrol Dial Transplant 2011; 26:3195-202. [PMID: 21382994 DOI: 10.1093/ndt/gfr084] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder resulting from the deficiency of trihexosylceramide α-galactosidase (α-Gal A). The diagnosis is often missed or delayed, and specific diagnostic tests (serum α-Gal A activity, genotyping or biopsy) are expensive and not widely available. We evaluated the diagnostic potential of urine microscopy in AFD. METHODS We studied 35 male and female AFD patients across a wide phenotypic spectrum and 21 controls with other renal diseases. Fresh urine sediment was examined under phase-contrast microscopy using polarized light for Maltese cross (MC) particles, anti-CD77 antibody to detect globotriaosylceramide (GL3, the substrate of α-Gal A), and anti-podocalyxin antibody to assess podocyte excretion. RESULTS Characteristic MC 2 particles and anti-CD77 binding within vacuolated urinary epithelial cells were both detected in AFD with high sensitivity and specificity (MC 2 detection sensitivity 100%, 95% confidence interval (CI) 85.4-100%, specificity 100%, CI 80.8-100%; anti-CD77-binding sensitivity 97.1%, CI 83.3-99.9, specificity 100%, CI 80.8-100%). Albuminuria (urinary albumin-to-creatinine ratio, ACR) correlated with quantitative particle excretion--in low, intermediate and high MC excretors, and median ACR was 1.6, 6.9 and 20.0 mg/μmol, respectively (analysis of variance P = 0.017). Podocyte staining was positive in ~50% of all AFD patients and was similar in those with and without clinical Fabry nephropathy (FN), whether or not treated with enzyme replacement. CONCLUSIONS Targeted urinary microscopy is a non-invasive, inexpensive, accessible and rapid diagnostic technique, especially applicable where serum α-Gal A activity and genotyping are not affordable or available. As the number of urinary MC 2 particles increases with rising albuminuria, the technique may also be useful in assessing FN burden.
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Affiliation(s)
- Mathu Selvarajah
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Melbourne, Australia
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Abstract
This study examined the efficacy and in vivo mechanism of action of the antifibrotic hormone, relaxin, in a mouse model of unilateral ureteric obstruction (UUO). Kidney fibrosis was assessed in recombinant human gene-2 relaxin-treated animals maintained for 3 and 9 d after UUO. Results were compared with untreated and unoperated animals (d 0). Total collagen, collagen subtypes (I, IV), TGF-β2 production, mothers against decapentaplegic homolog 2 (Smad2) phosphorylation, myofibroblast differentiation, mitosis, and apoptosis were all progressively increased by UUO (all P<0.05 vs. d 0 group at d 3 and d 9), whereas TGF-β1 production was increased and vascular endothelial growth factor expression (angiogenesis) decreased at d 9 (both P<0.05 vs. d 0). A progressive increase in matrix metalloproteinase (MMP)-2 after UUO suggested that it was reactive to the increased fibrogenesis. Conversely, MMP-9 was decreased at d 9, whereas its inhibitor tissue inhibitor of metalloproteinase-1 progressively decreased after UUO. Human gene-2 relaxin pretreatment of animals from 4 d prior to UUO ameliorated the increase in total collagen, collagen IV, Smad2 phosphorylation, and myofibroblasts at both time points (all P<0.05 vs. untreated groups) and inhibited TGF-β2 production and cell proliferation (both P<0.05 vs. untreated groups) with a trend toward normalizing vascular endothelial growth factor expression at d 9, with no effect on TGF-β1 production or apoptosis. The relaxin-mediated regulation of MMPs and tissue inhibitor of metalloproteinases in this model was not consistent with its antifibrotic properties. The beneficial effects of relaxin were lost when treatment was stopped. These findings establish that relaxin can inhibit both early and established phases of tubulointerstitial fibrosis, primarily by suppressing cell proliferation, myofibroblast differentiation, and collagen production. Not all of these effects paralleled changes to TGF-β-Smad signaling.
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Affiliation(s)
- Tim D Hewitson
- Howard Florey Institute, The University of Melbourne, and Department of Nephrology, The Royal Melbourne Hospital, Parkville, Victoria 3050, Australia.
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47
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Abstract
Glycoconjugates are complex macromolecules present in all tissues throughout the body. Depending on the tissue region, glycoconjugates express different carbohydrate moieties, which can be used to both distinguish cell type and examine changes in cell phenotype.Although the periodic acid-schiff (PAS) method has long been used to study the distribution of glycoconjugates, the usefulness of the technique is severely limited by its lack of specificity. A more specific technique makes use of the affinity that plant-derived lectins have for different carbohydrate moieties in glycoconjugates. Binding of lectins is therefore a particularly useful adjunct to conventional histology when it is important to characterise cell type. These well-characterised binding patterns have proved particularly valuable in helping us understand the pathogenesis of kidney disease, changes in cell surface carbohydrates on normal and neoplastic cells in tumours, and blood group biology.When labeled with a reporter molecule such as biotin or gold, lectin binding can be easily identified using light and electron microscopy. In this chapter, we describe the appropriate experimental protocols for light and electron microscopic examination of lectin binding, emphasising their utility in characterising nephron segments in renal disease.
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Affiliation(s)
- Su Ee Wong
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, VIC, Australia
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48
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Abstract
A number of techniques have been developed to use chemical, immunological, and molecular biology assays in histological material. Collectively termed histochemistry, these techniques have allowed us to better understand tissue and organ biology in situ. Success with each of these methods is dependent on the adequate preparation of material. In this article, we describe the basic steps required to prepare tissue for routine histochemical analysis.Histochemical techniques routinely use frozen and paraffin-embedded tissue as a basis for cellular and morphological analysis. Freezing tissue results in less alteration to epitopes and therefore may offer improved staining characteristics compared to techniques based on paraffin embedding. As in conventional histology, the use of fixation and embedding in more rigid media such as wax offers a number of potential advantages related to improved structural detail. Improvements in morphology may however be offset by a loss of antigens. The careful application of antigen retrieval techniques may overcome these deficiencies.
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Affiliation(s)
- Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, VIC, Australia
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49
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Abstract
Apoptosis is an important process both in normal biology and in various pathologies and disease states. Apoptosis in tissue or cells can be detected in a number of ways. In tissue sections, electron microscopy can identify apoptosis by cellular and nuclear morphology, and in live cells, changes in the membrane and membrane permeability allow apoptosis and necrosis to be observed. Histologically, apoptosis is best detected using the partial DNA degradation that is present in apoptotic cell nuclei. Terminal transferase-mediated UTP nick end-labeling (TUNEL) has been used successfully for detection of DNA degradation in paraffin-embedded tissue sections and can be combined with immunohistochemistry if desired to allow more precise identification of apoptotic cells.
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Affiliation(s)
- Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, VIC, Australia
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Hossain MA, Samuel CS, Binder C, Hewitson TD, Tregear GW, Wade JD, Bathgate RAD. The chemically synthesized human relaxin-2 analog, B-R13/17K H2, is an RXFP1 antagonist. Amino Acids 2009; 39:409-16. [DOI: 10.1007/s00726-009-0454-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 12/17/2009] [Indexed: 01/06/2023]
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