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Romi MM, Arfian N, Setyaningsih WAW, Putri RGP, Juffrie M, Sari DCR. Calcitriol Treatment Attenuates Uric Acid-Induced Kidney Injury via Super Oxide Dismutase-1 (SOD-1) Upregulation and Fibrosis Reduction. IRANIAN BIOMEDICAL JOURNAL 2021; 25:417-25. [PMID: 34641645 PMCID: PMC8744697 DOI: 10.52547/ibj.25.6.417] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 01/04/2021] [Indexed: 11/18/2022]
Abstract
Background Hyperuricemia induces nephropathy through the mediation of oxidative stress, tubular injury, inflammation, and fibrosis. The high uric acid level is associated with the reduction of vitamin D levels. However, the reno-protective effects of this vitamin in hyperuricemia condition remain unknown. This study aimed to elucidate calcitriol treatment in a uric acid-induced hyperuricemia mice model. Methods : Uric acid (125 mg/kg body weight [BW]) was administered intraperitoneally for 7 (UA7) and 14 (UA14) days. Calcitriol (0.5 g/kg BW) was intraperitoneally injected for the following seven days, after 14 days of uric acid induction (UA14VD7 group). The control group received NaCl 0.9%, by the same route. Serum creatinine was measured using calorimetric method, and uric acid levels were assessed using enzymatic calorimetric assay. Tubular injury and fibrosis were assessed using PAS and Sirius red staining. RT-PCR and real-time reverse transcription PCR were carried out for the analyses of SOD-1, Collagen-1, and TGF-1 mRNA expression in the kidney. Immunostaining of super oxide dismutase type 1 (SOD-1) was performed to detect its expression in the kidney. Results Uric acid and creatinine levels markedly increased in UA14 groups, followed by an exacerbation of tubular injury. RT-PCR revealed the upregulation of Collagen-1 and TGF-1, along with the downregulation of SOD-1. Calcitriol treatment attenuated the injury with reducing uric acid and creatinine levels, as well as tubular injury. This was associated with lower Collagen-1 and TGF-1 mRNA expression compared to the UA7 and UA14 groups. SOD-1 was upregulated in epithelial cells in the UA14VD7 group. Conclusion Calcitriol treatment after uric acid induction may attenuate kidney injury through upregulation of SOD-1 and downregulation of Collagen-1 and TGF-1 gene expression.
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Affiliation(s)
- Muhammad Mansyur Romi
- Department of Anatomy, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
- Doctoral Program in Medical Sciences, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Nur Arfian
- Department of Anatomy, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | | | - Rachma Greta Perdana Putri
- Department of Anatomical Pathology, Faculty of Medicine, Universitas Ahmad Dahlan, Yogyakarta, Indonesia
| | - Mohammad Juffrie
- Department of Pediatrics, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Dwi Cahyani Ratna Sari
- Department of Anatomy, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
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Kristensen T, Birn H, Ivarsen P. A randomised controlled unblinded multicentre non-inferiority trial with activated vitamin D and prednisolone treatment in patients with minimal change nephropathy (ADAPTinMCN). Trials 2021; 22:442. [PMID: 34247632 PMCID: PMC8273943 DOI: 10.1186/s13063-021-05393-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/23/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Minimal change nephropathy (MCN) is a common cause of nephrotic syndrome in both adults and children. International guidelines recommend treatment with prednisolone 1 mg/kg/day to adults. This dose is derived from an empirically established dose in children, although children generally attain remission faster and relapse more rapidly than adults. Prednisolone is associated with multiple and serious adverse events. Activated vitamin D has been shown to reduce albuminuria in other glomerular renal diseases with a minimum of adverse events. This study tests the hypothesis that a new treatment regimen in MCN combining reduced dose prednisolone and active vitamin D is as efficient in inducing remission and has fewer and less severe adverse events than standard prednisolone. Furthermore, we aim to establish models allowing for more personalized medicine based on assessment of the individual's prednisolone metabolism. METHODS A randomised controlled multicentre non-inferior unblinded trial including 96 adult, incident patients with biopsy-proven MCN, albuminuria > 3 g/day, and an estimated glomerular filtration rate (eGFR) > 30 ml/min from renal departments in Denmark. Patients are randomised to standard prednisolone (1 mg/kg/day) or reduced prednisolone (0.5 mg/kg/day) and alfacalcidol (0.5 μg/day). The primary outcome is the rate of remissions after 16 weeks and the time from diagnosis to remission. The study will include a saliva test to characterise prednisolone pharmacokinetics and compare them to genetic variations in specific liver enzymes responsible for prednisolone metabolism. DISCUSSION Reducing the prednisolone dose is expected to reduce the number of severe adverse events. This study will examine if reduced prednisolone dose with active vitamin D but without additional immunosuppression is feasible in the treatment of MCN and will reduce the number of adverse events. The findings can potentially change current guidelines for treatment of MCN in adults. Additional outcomes on inter-individual pharmacokinetic and metabolic variations may allow for a more personalised treatment strategy. TRIAL REGISTRATION EudraCT 2017-001206-16, ClinicalTrials.gov NCT03210688 . Registered on June 3, 2017.
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Affiliation(s)
- Tilde Kristensen
- Department of Internal Medicine, renal unit, Regional Hospital Viborg, and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
| | - Henrik Birn
- Department of Nephrology, Aarhus University Hospital and Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Per Ivarsen
- Department of Nephrology, Aarhus University Hospital, and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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Wu-Wong JR, Wessale JL, Chen YW, Chen T, Oubaidin M, Atsawasuwan P. A Novel Vitamin D Receptor Agonist, VS-105, Improves Bone Mineral Density without Affecting Serum Calcium in a Postmenopausal Osteoporosis Rat Model. JOURNAL OF EXPLORATORY RESEARCH IN PHARMACOLOGY 2020; 5:73-80. [PMID: 34589670 PMCID: PMC8478347 DOI: 10.14218/jerp.2020.00020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND OBJECTIVES VS-105, a novel vitamin D receptor agonist with significantly less hypercalcemic side effects than calcitriol, is a useful tool to investigate whether or not a vitamin D receptor agonist at non-hypercalcemic doses could improve bone mineral density (BMD). METHODS VS-105 and calcitriol were evaluated in an ovariectomized (OVX) osteoporosis rat model and in calvariae bone organ culture. RESULTS Treatment of OVX rats by VS-105 (0.1, 0.2 or 0.5 μg/kg, intraperitoneal, 3×/week, for 90 days) significantly improved BMD in the L3 lumbar vertebra in a dose-dependent manner (sham vs. OVX/vehicle: 324 ± 14 vs. 279 ± 10 mg/cm2; VS-105 at 0.1, 0.2 and 0.5 μg/kg: 306 ± 9, 329 ± 12, and 327 ± 10 mg/cm2, respectively) without affecting serum calcium (Ca). Calcitriol at 0.1 μg/kg significantly increased BMD but it also increased serum Ca. VS-105 and calcitriol at the test doses significantly suppressed serum parathyroid hormone and promoted tibia bone growth. With respect to biomarkers of bone remodeling, calcitriol and VS-105 both significantly elevated serum osteocalcin. In the calvariae bone organ culture, net Ca release was significantly less in VS-105-treated groups (vs. calcitriol). CONCLUSIONS VS-105 is efficacious in improving BMD in a dose range that does not affect serum Ca in OVX rats; the improvement in BMD by VS-105 is attributable to increased osteoblastic activity and reduced osteoclastic bone resorption.
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Affiliation(s)
- J. Ruth Wu-Wong
- Vidasym, Sioux Falls, SD, USA
- Correspondence to: J. Ruth Wu-Wong, Vidasym Inc., 2329 N Career Ave, #303, Sioux Falls, South Dakota, SD 57107 Tel: +1-847-863-9818; Fax: +1-847-260-8432.
| | | | | | | | - Maysaa Oubaidin
- Department of Orthodontics, University of Illinois, Chicago, IL, USA
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Vitamin D3 increases the Caspase-3 p12, MTHFR, and P-glycoprotein reducing amyloid-β42 in the kidney of a mouse model for Down syndrome. Life Sci 2019; 231:116537. [DOI: 10.1016/j.lfs.2019.06.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 05/30/2019] [Accepted: 06/05/2019] [Indexed: 02/07/2023]
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Vatakencherry RMJ, Saraswathy L. Association between vitamin D and hypertension in people coming for health check up to a tertiary care centre in South India. J Family Med Prim Care 2019; 8:2061-2067. [PMID: 31334180 PMCID: PMC6618207 DOI: 10.4103/jfmpc.jfmpc_236_19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 03/20/2019] [Accepted: 04/09/2019] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION Vitamin D has many effects apart from its role in calcium metabolism and bone health. Vitamin D is derived from endogenous ultraviolet-B induced vitamin D synthesis in the skin, and the current high prevalence of vitamin D deficiency in India, can be attributed to lifestyle related low sunlight exposure. Identification of the vitamin D receptor (VDR) in almost all human cells, suggests a role in extra skeletal diseases. Studies have shown that vitamin D deficiency is an independent risk factor for hypertension. AIM To evaluate the association between vitamin D and hypertension in people coming for health check up to a tertiary care center in South India. MATERIALS AND METHODS Study was carried out as a cross sectional study in a tertiary care hospital in South India. Participants (520) were both males and females (337 males and 183 females), between the age group of 20-60 years attending the comprehensive health check up clinic of our hospital. STATISTICAL ANALYSIS Statistical analysis was done using IBM SPSS statistics 20.0. RESULTS Severe vitamin D deficiency was highly prevalent in people with hypertension than in people without hypertension (P value <0.001). CONCLUSION Since India is a tropical country, till recently it was believed that vitamin D deficiency and its ill effects are uncommon. But it was found that, vitamin D deficiency was highly prevalent in people with hypertension in South India, emphasizing the need of early vitamin D supplementation. Therefore, to reduce cardiovascular morbidity, early identification of vitamin D deficiency and appropriate vitamin D supplementation may be of primary importance in population, especially like ours, having high prevalence.
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Affiliation(s)
- Rose Mary J. Vatakencherry
- Department of Physiology, Amrita School of Medicine, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham University, Kochi, Kerala
| | - L Saraswathy
- Department of Physiology, Amrita School of Medicine, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham University, Kochi, Kerala
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Yazdani S, Poosti F, Toro L, Wedel J, Mencke R, Mirković K, de Borst MH, Alexander JS, Navis G, van Goor H, van den Born J, Hillebrands JL. Vitamin D inhibits lymphangiogenesis through VDR-dependent mechanisms. Sci Rep 2017; 7:44403. [PMID: 28303937 PMCID: PMC5355885 DOI: 10.1038/srep44403] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 02/07/2017] [Indexed: 12/25/2022] Open
Abstract
Excessive lymphangiogenesis is associated with cancer progression and renal disease. Attenuation of lymphangiogenesis might represent a novel strategy to target disease progression although clinically approved anti-lymphangiogenic drugs are not available yet. VitaminD(VitD)-deficiency is associated with increased cancer risk and chronic kidney disease. Presently, effects of VitD on lymphangiogenesis are unknown. Given the apparently protective effects of VitD and the deleterious associations of lymphangiogenesis with renal disease, we here tested the hypothesis that VitD has direct anti-lymphangiogenic effects in vitro and is able to attenuate lymphangiogenesis in vivo. In vitro cultured mouse lymphatic endothelial cells (LECs) expressed VitD Receptor (VDR), both on mRNA and protein levels. Active VitD (calcitriol) blocked LEC tube formation, reduced LEC proliferation, and induced LEC apoptosis. siRNA-mediated VDR knock-down reversed the inhibitory effect of calcitriol on LEC tube formation, demonstrating how such inhibition is VDR-dependent. In vivo, proteinuric rats were treated with vehicle or paricalcitol for 6 consecutive weeks. Compared with vehicle-treated proteinuric rats, paricalcitol showed markedly reduced renal lymphangiogenesis. In conclusion, our data show that VitD is anti-lymphangiogenic through VDR-dependent anti-proliferative and pro-apoptotic mechanisms. Our findings highlight an important novel function of VitD demonstrating how it may have therapeutic value in diseases accompanied by pathological lymphangiogenesis.
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Affiliation(s)
- Saleh Yazdani
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Fariba Poosti
- Department of Pathology and Medical Biology, Division of Pathology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Luis Toro
- Department of Pathology and Medical Biology, Division of Pathology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Seccion de Nefrologia, Departamento de Medicina, Hospital Clinico Universidad de Chile, Santiago, Chile.,Centro de Investigacion Clinica Avanzada, Hospital Clinico Universidad de Chile, Santiago, Chile
| | - Johannes Wedel
- Department of Pathology and Medical Biology, Division of Pathology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Rik Mencke
- Department of Pathology and Medical Biology, Division of Pathology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Katarina Mirković
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Martin H de Borst
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - J Steven Alexander
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center-Shreveport, Louisiana, USA
| | - Gerjan Navis
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Harry van Goor
- Department of Pathology and Medical Biology, Division of Pathology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Jacob van den Born
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Jan-Luuk Hillebrands
- Department of Pathology and Medical Biology, Division of Pathology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Narasimhan S, Balasubramanian P. Role of Vitamin D in the Outcome of Ischemic Stroke- A Randomized Controlled Trial. J Clin Diagn Res 2017; 11:CC06-CC10. [PMID: 28384856 DOI: 10.7860/jcdr/2017/24299.9346] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 11/28/2016] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Vitamin D deficiency has reached epidemic proportions in India with prevalence rates of 70-100% in the general population. Low vitamin D levels are associated with worse outcomes in ischemic strokes. The outcome of stroke after vitamin D replenishment has not been much studied. AIM To compare the stroke outcome between patients receiving vitamin D supplementation and patients without vitamin D supplementation by Scandinavian Stroke Scale (SSS) and thus, to assess the long term outcome of ischemic stroke patients with low vitamin D level by supplementation of vitamin D. MATERIALS AND METHODS This is a non blinded randomized controlled trial conducted in ischemic stroke patients. The patients were divided into two groups (A and B) where Group A received a single dose of 6 lac IU of Cholecalciferol Intramascular (IM) injection and Group B were not given vitamin D. Finally 30 patients in each group were analyzed. SSS was applied to evaluate the stroke severity at the onset and at the follow up after three months in both groups. The difference in SSS was analyzed using SPSS software. Independent t-test was applied and p-value < 0.05 was taken as significant. RESULTS Mean±SD of vitamin D levels in Group A and Group B were 17.98±3.81ng/ml and 18.44±4.69 ng/ml respectively. Mean±SD of SSS at time of admission and after three months for Group A was 32.50±11.61 and 38.89±8.34; and for Group B 35.82±8.56 and 38.32±7.10. The difference in SSS from time of admission and after three months, in Group A (6.39±4.56) and Group B (2.50±2.20) were analyzed statistically and found to be highly significant (p<0.001). CONCLUSION The results showed that there is a significant improvement in the stroke outcome after three months in those patients who were supplemented with vitamin D. Thus screening for vitamin D deficiency in stroke patients is essential and vitamin D replenishment will improve the stroke outcome.
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Affiliation(s)
- Shuba Narasimhan
- Associate Professor, Department of Physiology, PSG Institute of Medical Sciences and Research , Coimbatore, Tamil Nadu, India
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8
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Abstract
Chronic kidney disease (CKD) is defined by reduced estimated glomerular filtration rate, increased proteinuria, or both. CKD affects more than 10% of US adults, or 20 million people, and the numbers are rising as the population ages. However, CKD remains underdiagnosed. Diabetes and hypertension are the most common causes of CKD. Although end-stage renal disease is a feared complication of CKD, patients with CKD have a much greater risk of dying of cardiovascular (CV) disease than progressing to kidney failure. Special effort should be made to address modifiable CV risk factors in patients with CKD.
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Affiliation(s)
- Meghan M Kiefer
- Division of General Internal Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
| | - Michael J Ryan
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
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Mirkovic K, Frenay ARS, van den Born J, van Goor H, Navis G, de Borst MH. Sodium restriction potentiates the renoprotective effects of combined vitamin D receptor activation and angiotensin-converting enzyme inhibition in established proteinuric nephropathy. Nephrol Dial Transplant 2015; 32:1293-1301. [DOI: 10.1093/ndt/gfv304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 07/11/2015] [Indexed: 01/02/2023] Open
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10
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Keyzer CA, de Jong MA, Fenna van Breda G, Vervloet MG, Laverman GD, Hemmelder M, Janssen WM, Lambers Heerspink HJ, Navis G, de Borst MH. Vitamin D receptor activator and dietary sodium restriction to reduce residual urinary albumin excretion in chronic kidney disease (ViRTUE study): rationale and study protocol. Nephrol Dial Transplant 2015; 31:1081-7. [PMID: 25744274 DOI: 10.1093/ndt/gfv033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/18/2015] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED Optimal albuminuria reduction is considered essential to halting chronic kidney disease (CKD) progression. Both vitamin D receptor activator (VDRA) treatment and dietary sodium restriction potentiate the efficacy of renin-angiotensin-aldosterone-system (RAAS) blockade to reduce albuminuria. The ViRTUE study addresses whether a VDRA in combination with dietary sodium restriction provides further albuminuria reduction in non-diabetic CKD patients on top of RAAS blockade. The ViRTUE study is an investigator-initiated, prospective, multi-centre, randomized, double-blind (paricalcitol versus placebo), placebo-controlled trial targeting stage 1-3 CKD patients with residual albuminuria of >300 mg/day due to non-diabetic glomerular disease, despite angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use. During run-in, all subjects switched to standardized RAAS blockade (ramipril 10 mg/day) and blood pressure titrated to <140/90 mmHg according to a standardized protocol. Eligible patients are subsequently enrolled and undergo four consecutive study periods in random order of 8 weeks each: (i) paricalcitol (2 µg/day) combined with a liberal sodium diet (∼200 mmol Na(+)/day, i.e. mean sodium intake in the general population), (ii) paricalcitol (2 µg/day) combined with dietary sodium restriction (target: 50 mmol Na(+)/day), (iii) placebo combined with a liberal sodium diet and (iv) placebo combined with dietary sodium restriction. Data are collected at the end of each study period. The primary outcome is 24-h urinary albumin excretion. Secondary study outcomes are blood pressure, renal function (estimated glomerular filtration rate), plasma renin activity and, in a sub-population (N = 9), renal haemodynamics (measured glomerular filtration rate and effective renal plasma flow). A sample size of 50 patients provides 90% power to detect a 23% reduction in albuminuria, assuming a 25% dropout rate. Further reduction of residual albuminuria by combination of VDRA treatment and sodium restriction during single-agent RAAS-blockade will justify long-term studies on cardiorenal outcomes and safety. CLINICAL TRIAL REGISTRATION NTR2898 (Dutch trial register).
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Affiliation(s)
- Charlotte A Keyzer
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Maarten A de Jong
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - G Fenna van Breda
- Department of Nephrology and Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Marc G Vervloet
- Department of Nephrology and Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Gozewijn D Laverman
- Department of Internal Medicine, Division of Nephrology, ZGT Hospital, Almelo, The Netherlands
| | - Marc Hemmelder
- Department of Internal Medicine, Division of Nephrology, Medical Center Leeuwarden, Leeuwarden, The Netherlands
| | - Wilbert M Janssen
- Department of Internal Medicine, Division of Nephrology, Martini Hospital Groningen, Groningen, The Netherlands
| | - Hiddo J Lambers Heerspink
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Gerjan Navis
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Martin H de Borst
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Humalda JK, Goldsmith DJA, Thadhani R, de Borst MH. Vitamin D analogues to target residual proteinuria: potential impact on cardiorenal outcomes. Nephrol Dial Transplant 2015; 30:1988-94. [PMID: 25609737 DOI: 10.1093/ndt/gfu404] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 11/28/2014] [Indexed: 12/11/2022] Open
Abstract
Residual proteinuria, the amount of proteinuria that remains during optimally dosed renin-angiotensin-aldosterone system (RAAS) blockade, is an independent risk factor for progressive renal function loss and cardiovascular complications in chronic kidney disease (CKD) patients. Dual RAAS blockade may reduce residual proteinuria but without translating into improved cardiorenal outcomes at least in diabetic nephropathy; rather, dual RAAS blockade may increase the risk of adverse events. These findings have challenged the concept of residual proteinuria as an absolute treatment target. Therefore, new strategies must be explored to address whether by further reduction of residual proteinuria using interventions not primarily targeting the RAAS benefit in terms of cardiorenal risk reduction would accrue. Both clinical and experimental intervention studies have demonstrated that vitamin D can reduce residual proteinuria through both RAAS-dependent and RAAS-independent pathways. Future research should prospectively explore vitamin D treatment as an adjunct to RAAS blockade in an interventional trial exploring clinically relevant cardiorenal end points.
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Affiliation(s)
- Jelmer K Humalda
- Division of Nephrology, Department of Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | | | - Ravi Thadhani
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Martin H de Borst
- Division of Nephrology, Department of Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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12
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Wu-Wong JR, Chen YW, Wessale JL. Vitamin D receptor agonist VS-105 improves cardiac function in the presence of enalapril in 5/6 nephrectomized rats. Am J Physiol Renal Physiol 2014; 308:F309-19. [PMID: 25503724 DOI: 10.1152/ajprenal.00129.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Vitamin D receptor (VDR) agonists (VDRAs) are commonly used to manage hyperparathyroidism secondary to chronic kidney disease (CKD). Patients with CKD experience extremely high risks of cardiovascular morbidity and mortality. Clinical observations show that VDRA therapy may be associated with cardio-renal protective and survival benefits in patients with CKD. The 5/6 nephrectomized (NX) Sprague-Dawley rat with established uremia exhibits elevated serum parathyroid hormone (PTH), hypertension, and abnormal cardiac function. Treatment of 5/6 NX rats with VS-105, a novel VDRA (0.05 and 0.5 μg/kg po by gavage), once daily for 8 wk in the presence or absence of enalapril (30 mg/kg po via drinking water) effectively suppressed serum PTH without raising serum calcium. VS-105 alone reduced systolic blood pressure (from 174 ± 6 to 145 ± 9 mmHg, P < 0.05) as effectively as enalapril (from 174 ± 6 to 144 ± 7 mmHg, P < 0.05). VS-105 improved cardiac functional parameters such as E/A ratio, ejection fraction, and fractional shortening with or without enalapril. Enalapril or VS-105 alone significantly reduced left ventricular hypertrophy (LVH); VS-105 plus enalapril did not further reduce LVH. VS-105 significantly reduced both cardiac and renal fibrosis. The lack of hypercalcemic toxicity of VS-105 is due to its lack of effects on stimulating intestinal calcium transport and inducing the expression of intestinal calcium transporter genes such as Calb3 and TRPV6. These studies demonstrate that VS-105 is a novel VDRA that may provide cardiovascular benefits via VDR activation. Clinical studies are required to confirm the cardiovascular benefits of VS-105 in CKD.
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Nolan KA, Brennan EP, Scholz CC, Cullen C, Ryan A, Taylor CT, Godson C. Paricalcitol protects against TGF-β1-induced fibrotic responses in hypoxia and stabilises HIF-α in renal epithelia. Exp Cell Res 2014; 330:371-381. [PMID: 25107382 DOI: 10.1016/j.yexcr.2014.07.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 07/25/2014] [Accepted: 07/26/2014] [Indexed: 01/12/2023]
Abstract
Epithelial injury and tubulointerstitial fibrosis (TIF) within a hypoxic microenvironment are associated with progressive loss of renal function in chronic kidney disease [CKD]. Transforming growth factor beta-1 (TGF-β1) is an important mediator of renal fibrosis. Growing evidence suggests that Vitamin D [1,25-(OH)2D] and its analogues may have a renoprotective effect in CKD. Here we examined the protective effect of the vitamin D analogue paricalcitol [PC; 19-nor-1α,3β,25-trihydroxy-9,10-secoergosta-5(Z),7(E) 22(E)-triene] on the responses of human renal epithelial cells to TGF-β1. PC attenuated TGF-β1-induced Smad 2 phosphorylation and upregulation of the Notch ligand Jagged-1, α-smooth muscle actin and thrombospondin-1 and prevented the TGF-β1-mediated loss of E-Cadherin. To mimic the hypoxic milieu of CKD we cultured renal epithelial cells in hypoxia [1% O2] and observed similar attenuation by PC of TGF-β1-induced fibrotic responses. Furthermore, in cells cultured in normoxia [21% O2], PC induced an accumulation of hypoxia-inducible transcription factors (HIF) 1α and HIF-2α in a time and concentration [1 µM-2 µM] dependent manner. Here, PC-induced HIF stabilisation was dependent on activation of the PI-3Kinase pathway. This is the first study to demonstrate regulation of the HIF pathway by PC which may have importance in the mechanism underlying renoprotection by PC.
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Affiliation(s)
- Karen A Nolan
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Eoin P Brennan
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Carsten C Scholz
- Systems Biology Ireland, Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Cliodhna Cullen
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Aidan Ryan
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Cormac T Taylor
- Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Catherine Godson
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
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Abstract
Chronic kidney disease (CKD) has been recognized as a significant global health problem because of the increased risk of total and cardiovascular morbidity and mortality. Vitamin D deficiency or insufficiency is common in patients with CKD, and serum levels of vitamin D appear to have an inverse correlation with kidney function. Growing evidence has indicated that vitamin D deficiency may contribute to deteriorating renal function, as well as increased morbidity and mortality in patients with CKD. Recent studies have suggested that treatment with active vitamin D or its analogues can ameliorate renal injury by reducing fibrosis, apoptosis, and inflammation in animal models; this treatment also decreases proteinuria and mortality in patients with CKD. These renoprotective effects of vitamin D treatment are far beyond its classical role in the maintenance of bone and mineral metabolism, in addition to its pleiotropic effects on extra-mineral metabolism. In this review, we discuss the altered metabolism of vitamin D in kidney disease, and the potential renoprotective mechanisms of vitamin D in experimental and clinical studies. In addition, issues regarding the effects of vitamin D treatment on clinical outcomes are discussed.
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Affiliation(s)
- Chang Seong Kim
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Soo Wan Kim
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
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Barnett N, Zhao Z, Koyama T, Janz DR, Wang CY, May AK, Bernard GR, Ware LB. Vitamin D deficiency and risk of acute lung injury in severe sepsis and severe trauma: a case-control study. Ann Intensive Care 2014; 4:5. [PMID: 24559079 PMCID: PMC3944729 DOI: 10.1186/2110-5820-4-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 02/13/2014] [Indexed: 12/30/2022] Open
Abstract
Background The aim of this study was to determine the association between 25-hydroxyvitamin D (25-OHD) levels at the onset of critical illness and the development of acute lung injury/acute respiratory distress syndrome (ALI/ARDS) in patients with sepsis or trauma. Methods We performed two nested case-control studies of 478 patients with sepsis and trauma with or without ALI/ARDS admitted to the medical, surgical and trauma ICUs of a tertiary-care center. Cases consisted of patients with either sepsis or trauma and ALI/ARDS; controls consisted of equivalent numbers of matched patients with either sepsis or trauma alone. We measured serum 25-OHD levels the morning after ICU admission and used multivariable regression to assess the relationship between 25-OHD and diagnosis of ALI/ARDS during the first four ICU days, controlling for age, gender, diabetes, smoking status and season. Results 25-OHD levels did not differ between cases with ALI/ARDS and controls in either the sepsis or trauma cohorts. Using a conditional logistic regression model, sepsis patients during the winter season with higher 25-OHD levels were more likely to develop acute lung injury (odds ratio 1.68, 95% confidence interval of 1.05 to 2.69, P = 0.03). This association did not hold for the trauma cohort in either season. Sepsis and trauma patients had a lower risk of hospital mortality at higher 25-OHD levels but neither relationship reached significance. Higher one-year mortality after trauma was associated with lower 25-OHD levels (HR 0.50, CI 0.35,0.72 P = 0.001). Conclusions Serum 25-OHD measured early after admission to intensive care is not associated with the development of acute lung injury, hospital or one-year mortality in critically ill patients with sepsis although lower 25-OHD levels were associated with higher one-year mortality in patients with severe trauma.
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Affiliation(s)
| | | | | | | | | | | | | | - Lorraine B Ware
- Division of Allergy, Pulmonary and Critical Care Medicine in the Department of Medicine, Vanderbilt University, T1218 MCN, 1161 21st Avenue South, Nashville, TN, USA.
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Chen B, Kawai M, Wu-Wong JR. Synthesis of VS-105: A novel and potent vitamin D receptor agonist with reduced hypercalcemic effects. Bioorg Med Chem Lett 2013; 23:5949-52. [PMID: 24035340 DOI: 10.1016/j.bmcl.2013.08.076] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 08/13/2013] [Accepted: 08/15/2013] [Indexed: 12/28/2022]
Abstract
We have synthesized a novel vitamin D receptor agonist VS-105 ((1R,3R)-5-((E)-2-((3αS,7αS)-1-((R)-1-((S)-3-hydroxy-2,3-dimethylbutoxy)ethyl)-7α-methyldihydro-1H-inden-4(2H,5H,6H,7H,7αH)-ylidene)ethylidene)-2-methylenecyclohexane-1,3-diol). Preparation of a-ring phenylphosphine oxide 11, followed by Wittig-Horner coupling of 11 with the protected 25-hydroxy Grundmann's ketone 22 generated the precursor 12. Deprotection of the TBDMS groups of 12 produced the target compound VS-105. The biological profiles of VS-105 were evaluated using in vitro assays (VDR receptor binding, VDR reporter gene and HL-60 differentiation) in comparison to calcitriol (the endogenous hormone) or paricalcitol. Furthermore, the PTH suppressing potency and hypercalcemic side effects of VS-105 were evaluated in the 5/6 nephrectomized uremic rats in comparison to paricalcitol. Combining various changes at 20-epi, 22-oxa, 24-methyl, and 2-methylene yielded VS-105 that not only is highly potent in inducing functional responses in vitro, but also effectively suppresses PTH in a dose range that does not affect serum calcium in the 5/6 nephrectomized uremic rats.
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Affiliation(s)
- Barbara Chen
- Vidasym, 2201 W. Campbell Park Dr., Suite 13, Chicago, IL 60612, United States
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18
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Liu ZM, Woo J, Wu SH, Ho SC. The role of vitamin D in blood pressure, endothelial and renal function in postmenopausal women. Nutrients 2013; 5:2590-610. [PMID: 23839167 PMCID: PMC3738990 DOI: 10.3390/nu5072590] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Revised: 06/25/2013] [Accepted: 06/26/2013] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Vitamin D is a pro-hormone that plays an essential role in the vasculature and in kidney function. AIMS To review the extra-skeletal effects of vitamin D on blood pressure, endothelial and renal function with emphasis on recent findings in postmenopausal women. METHODS Included in this review was a PubMed database search for English language articles through March 2013. This review discussed the physiology and definition of vitamin D deficiency, the recent evidence for the role vitamin D in blood pressure, vascular and renal function. RESULTS Experimental and epidemiological data suggest that vitamin D plays an important role in the vasculature and in kidney function. Low vitamin D concentrations appear to significantly associate with hypertension, endothelial and renal dysfunction. However, the results of clinical trials have generally been mixed. Studies specifically conducted among postmenopausal women are limited and findings are still inconsistent. CONCLUSIONS Definitive studies are warranted to elucidate the effects of vitamin D supplementation on vascular and renal function and a more detailed work is needed to outline the route, duration and optimal dose of supplementation. It is premature to recommend vitamin D as a therapeutic option in the improvement of vascular and renal function at the current stage.
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Affiliation(s)
- Zhao-Min Liu
- Department of Medicine & Therapeutics, the Chinese University of Hong Kong, Hong Kong SAR, 999077, China; E-Mail:
| | - Jean Woo
- Department of Medicine & Therapeutics, the Chinese University of Hong Kong, Hong Kong SAR, 999077, China; E-Mail:
| | - Sheng-Hui Wu
- Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37203-1738, USA; E-Mail:
| | - Suzanne C. Ho
- Division of Epidemiology, The Jockey Club School of Public Health and Primary Care, the Chinese University of Hong Kong, Hong Kong SAR, 999077, China
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Wu-Wong JR, Kawai M, Chen YW, Wessale JL, Huang CJ, Wu MT, Nakane M. Two novel vitamin D receptor modulators with similar structures exhibit different hypercalcemic effects in 5/6 nephrectomized uremic rats. Am J Nephrol 2013; 37:310-9. [PMID: 23548814 DOI: 10.1159/000348755] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 02/07/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND/AIMS Vitamin D receptor modulators (VDRMs) are indicated for secondary hyperparathyroidism in chronic kidney disease (CKD). Clinical observations demonstrate that VDRM therapy provides cardiovascular (CV) benefit in CKD. Current on-market VDRMs have a narrow therapeutic index at 1- to 4-fold [hypercalcemic toxicity vs. parathyroid hormone (PTH)-suppressing efficacy]. Hypercalcemia leads to the need for frequent drug dose titration and serum calcium (Ca) monitoring. A VDRM with a wider therapeutic index and beneficial CV effects will be clinically useful. METHODS Two structurally similar VDRMs were tested in the 5/6 nephrectomized (NX) rats with elevated PTH, endothelial dysfunction and left ventricular hypertrophy. RESULTS VS-110 and VS-411 at 0.01-1 μg/kg (i.p. 3 times/week for 2 weeks) suppressed serum PTH effectively. VS-411 raised serum Ca with an 11% increase at 0.01 μg/kg (therapeutic index = ~1-fold), while VS-110 did not raise serum Ca even at 1 μg/kg (therapeutic index >50-fold). VS-110 improved endothelium-dependent aortic relaxation in a dose-dependent manner and significantly reduced left ventricular fibrosis without affecting serum Ca. VS-411 also exhibited effects on the CV parameters, but was less potent at the high doses with severe hypercalcemia. VS-110 and VS-411 specifically activated the reporter gene via a chimeric receptor containing the VDR ligand binding domain with EC(50) <0.1 nM. CONCLUSIONS Structurally similar VDRMs can exhibit distinctly different hypercalcemic effects in 5/6 NX uremic rats. While differences exist for the Ca and CV effects of VS-110 and VS-411, the clinical implications are unclear. VS-110's results are promising but clinical outcome studies need to be performed.
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Wu-Wong JR, Nakane M, Chen YW. Mapping the time-dependent effects of paricalcitol on serum calcium, phosphorus and parathyroid hormone levels in 5/6 nephrectomized uremic rats. Life Sci 2012; 92:161-6. [PMID: 23261531 DOI: 10.1016/j.lfs.2012.11.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 10/24/2012] [Accepted: 11/20/2012] [Indexed: 01/20/2023]
Abstract
AIMS To investigate whether the frequency of monitoring paricalcitol's impact on serum calcium (Ca), phosphorus and PTH in current clinical practice is sufficient by mapping the time-dependent effects of paricalcitol on these parameters. MAIN METHODS The 5/6 nephrectomized (NX) male, Sprague-Dawley rats with established uremia were treated with vehicle or paricalcitol (0.16 μg/kg, i.p., 3×/week). On Day 0 (before treatment), Days 12 and 13 after treatment, and also at 0, 1, 4, 8, 16, 24 h after the last dosing, blood and small intestine samples were collected. KEY FINDINGS Serum creatinine and blood urea nitrogen levels were significantly elevated in 5/6 NX rats. Significant increases were observed in serum Ca while PTH decreased by >90% when the parameters were determined at 12 or 13 days after paricalcitol dosing. Paricalcitol caused a step-wise increase in serum Ca levels at 1-24 h following dosing, reduced serum PTH levels with PTH values ranging from 1.06±0.06 to 26.7±25.7 pg/ml (vs. 152±15 pg/ml in Sham rats), but did not affect serum phosphorus in a time-dependent manner. Consistent with the serum Ca data, paricalcitol significantly induced the intestinal expression of Calb3 and TRPV6, genes involved in intestinal Ca transport, and also significantly induced the intestinal calcium absorption. SIGNIFICANCE Our results suggest that the frequency of monitoring paricalcitol's effect on serum Ca, phosphorus and PTH in current clinical practice seems adequate. Additional clinical trials may be needed to resolve the inconsistent clinical observations about the impact of paricalcitol on serum Ca.
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Affiliation(s)
- J Ruth Wu-Wong
- Department of Pharmacy Practice, University of Illinois at Chicago, Chicago, IL 60612-7230, USA.
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Mirković K, de Borst MH. Beyond the RAAS: dissecting the antifibrotic effects of vitamin D analogues. J Transl Med 2012; 92:1666-9. [PMID: 23191989 DOI: 10.1038/labinvest.2012.150] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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[Therapeutic strategies to prevent chronic kidney disease progression]. Internist (Berl) 2012; 53:810-6. [PMID: 22714581 DOI: 10.1007/s00108-011-3012-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Chronic kidney disease (CKD) is highly prevalent. Independent from the underlying disease, measures capable of decreasing the progression of CKD have been identified. Lowering of blood pressure and proteinuria are most important. As the potential risk of aggressive blood pressure-lowering strategies has become obvious, the current very low blood pressure goals are doubted. Thus, patients have to be treated individually taking into consideration each patient's preexisting cardiovascular damage and the risk of CKD progression. Additional modifiable risk factors are blood glucose in diabetic patients, lipids, anemia, uric acid, vitamin D, protein intake, and smoking.
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Wu-Wong JR, Kawai M, Chen YW, Nakane M. VS-105: a novel vitamin D receptor modulator with cardiovascular protective effects. Br J Pharmacol 2012; 164:551-60. [PMID: 21557735 DOI: 10.1111/j.1476-5381.2011.01473.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE Vitamin D receptor (VDR) modulators (VDRMs) such as calcitriol, paricalcitol and doxercalciferol are commonly used to manage hyperparathyroidism secondary to chronic kidney disease (CKD). CKD patients experience extremely high risks of cardiovascular morbidity and mortality. Clinical observations show that VDRM therapy may be associated with cardio-renal protective and survival benefits for CKD patients. However, hypercalcaemia remains a serious side effect for current VDRMs, which leads to the need for frequent dose titration and serum Ca (calcium) monitoring. Significant clinical benefits can be derived from a VDRM with cardiovascular protective effects without the hypercalcaemic liability. EXPERIMENTAL APPROACH Male Sprague-Dawley rats were 5/6 nephrectomized and 6 weeks later, after they had established uraemia, elevated parathyroid hormone levels, endothelial dysfunction and left ventricular hypertrophy, the rats were treated with VS-105, a novel VDRM. The effects of VS-105 were also tested in cultured HL-60 cells. KEY RESULTS VS-105 induced HL-60 cell differentiation with an EC₅₀ value at 11.8 nM. Treatment (i.p., 3× a week over a period of 2 weeks) of the 5/6 nephrectomized rats by VS-105 (0.004-0.64 µg·kg⁻¹) effectively suppressed serum parathyroid hormone without raising serum Ca or phosphate levels. Furthermore, 2 weeks of treatment with VS-105 improved endothelium-dependent aortic relaxation and attenuated left ventricular abnormalities in a dose range that did not affect serum Ca levels. Similar results were obtained when VS-105 was administered i.p. or by oral gavage. CONCLUSIONS AND IMPLICATIONS VS-105 exhibits an overall therapeutic product profile that supports expanded use in CKD to realize the cardiovascular protective effects of VDR activation.
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Abstract
Renal fibrosis, particularly tubulointerstitial fibrosis, is the common final outcome of almost all progressive chronic kidney diseases. Renal fibrosis is also a reliable predictor of prognosis and a major determinant of renal insufficiency. Irrespective of the initial causes, renal fibrogenesis is a dynamic and converging process that consists of four overlapping phases: priming, activation, execution and progression. Nonresolving inflammation after a sustained injury sets up the fibrogenic stage (priming) and triggers the activation and expansion of matrix-producing cells from multiple sources through diverse mechanisms, including activation of interstitial fibroblasts and pericytes, phenotypic conversion of tubular epithelial and endothelial cells and recruitment of circulating fibrocytes. Upon activation, matrix-producing cells assemble a multicomponent, integrin-associated protein complex that integrates input from various fibrogenic signals and orchestrates the production of matrix components and their extracellular assembly. Multiple cellular and molecular events, such as tubular atrophy, microvascular rarefaction and tissue hypoxia, promote scar formation and ensure a vicious progression to end-stage kidney failure. This Review outlines our current understanding of the cellular and molecular mechanisms of renal fibrosis, which could offer novel insights into the development of new therapeutic strategies.
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