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Alvarez Jerez P, Alcantud JL, de Los Reyes-Ramírez L, Moore A, Ruz C, Vives Montero F, Rodriguez-Losada N, Saini P, Gan-Or Z, Alvarado CX, Makarious MB, Billingsley KJ, Blauwendraat C, Noyce AJ, Singleton AB, Duran R, Bandres-Ciga S. Exploring the genetic and genomic connection underlying neurodegeneration with brain iron accumulation and the risk for Parkinson's disease. NPJ Parkinsons Dis 2023; 9:54. [PMID: 37024536 PMCID: PMC10079978 DOI: 10.1038/s41531-023-00496-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/16/2023] [Indexed: 04/08/2023] Open
Abstract
Neurodegeneration with brain iron accumulation (NBIA) represents a group of neurodegenerative disorders characterized by abnormal iron accumulation in the brain. In Parkinson's Disease (PD), iron accumulation is a cardinal feature of degenerating regions in the brain and seems to be a key player in mechanisms that precipitate cell death. The aim of this study was to explore the genetic and genomic connection between NBIA and PD. We screened for known and rare pathogenic mutations in autosomal dominant and recessive genes linked to NBIA in a total of 4481 PD cases and 10,253 controls from the Accelerating Medicines Partnership Parkinsons' Disease Program and the UKBiobank. We examined whether a genetic burden of NBIA variants contributes to PD risk through single-gene, gene-set, and single-variant association analyses. In addition, we assessed publicly available expression quantitative trait loci (eQTL) data through Summary-based Mendelian Randomization and conducted transcriptomic analyses in blood of 1886 PD cases and 1285 controls. Out of 29 previously reported NBIA screened coding variants, four were associated with PD risk at a nominal p value < 0.05. No enrichment of heterozygous variants in NBIA-related genes risk was identified in PD cases versus controls. Burden analyses did not reveal a cumulative effect of rare NBIA genetic variation on PD risk. Transcriptomic analyses suggested that DCAF17 is differentially expressed in blood from PD cases and controls. Due to low mutation occurrence in the datasets and lack of replication, our analyses suggest that NBIA and PD may be separate molecular entities.
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Affiliation(s)
- Pilar Alvarez Jerez
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Jose Luis Alcantud
- Institute of Neurosciences "Federico Olóriz", Centro de Investigación Biomédica, Universidad de Granada, Granada, Spain
| | - Lucia de Los Reyes-Ramírez
- Laboratory of Neuropharmacology. Dept. Medicine and Life Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| | - Anni Moore
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | - Clara Ruz
- Institute of Neurosciences "Federico Olóriz", Centro de Investigación Biomédica, Universidad de Granada, Granada, Spain
| | - Francisco Vives Montero
- Institute of Neurosciences "Federico Olóriz", Centro de Investigación Biomédica, Universidad de Granada, Granada, Spain
| | - Noela Rodriguez-Losada
- Department Human Physiology, Faculty of Medicine, Biomedicine Research Institute of Malaga (IBIMA C07), University of Malaga, Malaga, Spain
| | - Prabhjyot Saini
- Montreal Neurological Institute, McGill University, Montréal, QC, Canada
- Department of Human Genetics, McGill University, Montréal, QC, Canada
| | - Ziv Gan-Or
- Montreal Neurological Institute, McGill University, Montréal, QC, Canada
- Department of Human Genetics, McGill University, Montréal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - Chelsea X Alvarado
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
- Data Tecnica International, Washington, DC, USA
| | - Mary B Makarious
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Kimberley J Billingsley
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Cornelis Blauwendraat
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Alastair J Noyce
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
- Preventive Neurology Unit, Centre for Prevention, Detection and Diagnosis, Wolfson Institute of Population Health, Queen Mary University of London, London, UK
| | - Andrew B Singleton
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Raquel Duran
- Institute of Neurosciences "Federico Olóriz", Centro de Investigación Biomédica, Universidad de Granada, Granada, Spain
| | - Sara Bandres-Ciga
- Molecular Genetics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA.
- Center for Alzheimer's and Related Dementias (CARD), National Institute on Aging and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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Psoriasis and Cardiometabolic Diseases: Shared Genetic and Molecular Pathways. Int J Mol Sci 2022; 23:ijms23169063. [PMID: 36012327 PMCID: PMC9409274 DOI: 10.3390/ijms23169063] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/26/2022] Open
Abstract
A convincing deal of evidence supports the fact that severe psoriasis is associated with cardiovascular diseases. However, the precise underlying mechanisms linking psoriasis and cardiovascular diseases are not well defined. Psoriasis shares common pathophysiologic mechanisms with atherosclerosis and cardiovascular (CV) risk factors. In particular, polymorphism in the IL-23R and IL-23 genes, as well as other genes involved in lipid and fatty-acid metabolism, renin–angiotensin system and endothelial function, have been described in patients with psoriasis and with cardiovascular risk factors. Moreover, systemic inflammation in patients with psoriasis, including elevated serum proinflammatory cytokines (e.g., TNF-α, IL-17, and IL-23) may contribute to an increased risk of atherosclerosis, hypertension, alteration of serum lipid composition, and insulin resistance. The nonlinear and intricate interplay among various factors, impacting the molecular pathways in different cell types, probably contributes to the development of psoriasis and cardiovascular disease (CVD). Future research should, therefore, aim to fully unravel shared and differential molecular pathways underpinning the association between psoriasis and CVD.
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Parizadeh SM, Rezayi M, Jafarzadeh-Esfehani R, Avan A, Ghazizadeh H, Emadzadeh M, Sahebi R, Ferns GA, Ghayour-Mobarhan M. Association of vitamin D status with liver and kidney disease: A systematic review of clinical trials, and cross-sectional and cohort studies. INT J VITAM NUTR RES 2021; 91:175-187. [DOI: 10.1024/0300-9831/a000540] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Abstract. Background: Vitamin D deficiency (VDD) is a major public health problem. There are few comprehensive systematic reviews about the relationship between Vitamin D status and liver and renal disease in Iran. Methods: We systemically searched the following databases: Web of Science; PubMed; Cochrane Library; Scopus; Science Direct; Google Scholar and two Iranian databases (Scientific Information Database (SID) and IranMedex) up until November 2017 to identify all randomized control trials (RCTs), case control, cross-sectional and cohort studies investigating the association between vitamin D and any form of liver or kidney disease. Results: Vitamin D insufficiency, or deficiency (VDD), is highly prevalent in Iran, reports varying between 44.4% in Isfahan to 98% in Gorgan. There is also a high prevalence of VDD among patients with liver or kidney disease, and the administration of vitamin D supplements may have beneficial effects on lipid profile, blood glucose, liver function and fatty liver disease, and bone health. Low serum vitamin D levels are related with abnormalities in these laboratory and clinical parameters. Conclusion: VDD is prevalent in patients with chronic liver or renal disease in Iran. There appear to be several beneficial effects of vitamin D supplementation in vitamin D deficient patients with liver or kidney disease.
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Affiliation(s)
- Seyed Mostafa Parizadeh
- Metabolic Syndrome Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Majid Rezayi
- Metabolic Syndrome Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Modern Sciences and Technologies, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Reza Jafarzadeh-Esfehani
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amir Avan
- Metabolic Syndrome Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Modern Sciences and Technologies, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hamideh Ghazizadeh
- Department of Modern Sciences and Technologies, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Category 2 Institutes and Centers under the Auspices of UNESCO, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Maryam Emadzadeh
- Clinical Research Unit, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Reza Sahebi
- Department of Modern Sciences and Technologies, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Molecular Medicine, School of Advanced Technologies, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Gordon A. Ferns
- Division of Medical Education, Brighton & Sussex Medical School, Falmer, Brighton, UK
| | - Majid Ghayour-Mobarhan
- Metabolic Syndrome Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Category 2 Institutes and Centers under the Auspices of UNESCO, Mashhad University of Medical Sciences, Mashhad, Iran
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Schwartz JB, Moore KL, Yin M, Sharma A, Merenstein D, Islam T, Golub ET, Tien PC, Adeyemi OM. Relationship of vitamin D, HIV, HIV treatment, and lipid levels in the Women's Interagency HIV Study of HIV-infected and uninfected women in the United States. J Int Assoc Provid AIDS Care 2014; 13:250-9. [PMID: 24668135 DOI: 10.1177/2325957413506748] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Relationships between vitamin D, lipids, HIV infection, and HIV treatment (±antiretroviral therapy [ART]) were investigated with Women's Interagency HIV Study data (n = 1758 middle-aged women) using multivariable regression. Sixty-three percent of women had vitamin D deficiency. Median 25-hydroxyvitamin D (25-OH vitamin D) was highest in HIV-infected + ART-treated women (17 ng/mL; P < .001) and was the same in HIV-uninfected or HIV-infected women without ART (14 ng/mL). Vitamin D levels were lower if efavirenz (EFV) was included in ART (15 versus 19 ng/mL; P < .001). The most common lipid abnormality was high triglycerides (≥200 mg/dL) in HIV-infected + ART-treated women (13% versus 7% of HIV-infected without ART and 5% of HIV-uninfected; P < .001), with a positive relationship between 25-OH vitamin D and triglycerides (95% confidence interval 0.32-1.69; P < .01). No relationships between 25-OH vitamin D and cholesterol were detected. Vitamin D deficiency is common irrespective of HIV status but influenced by HIV treatment. Similarly, vitamin D levels were positively related to triglycerides only in ART-treated HIV-infected women and unrelated to cholesterol.
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Wang H, Xia N, Yang Y, Peng DQ. Influence of vitamin D supplementation on plasma lipid profiles: a meta-analysis of randomized controlled trials. Lipids Health Dis 2012; 11:42. [PMID: 22433171 PMCID: PMC3325888 DOI: 10.1186/1476-511x-11-42] [Citation(s) in RCA: 166] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 03/20/2012] [Indexed: 12/17/2022] Open
Abstract
Observational studies have shown that low serum levels of vitamin D have been associated with an atherogenic lipid profile. However, the intervention studies gave divergent results. We conducted a meta-analysis of randomized controlled trials that evaluated the effects of vitamin D supplementation on blood lipids. A systematic literature search was conducted via MEDLINE, Cochrane library, and EMBASE for randomized controlled clinical trials assessing the effects of vitamin D supplementation on lipids. The mean change in total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG) from baseline was treated as a continuous variable. In all, 12 clinical trials consisting of 1346 participants were included in the analysis. The pooled estimate of effect for vitamin D supplementation on LDL-C was 3.23 mg/dl (95% confidence interval, 0.55 to 5.90 mg/dl). No statistically significant effects for vitamin D supplementation were observed for TC, HDL-C and TG (differences in means were 1.52 mg/dl (-1.42 to 4.46 mg/dl), -0.14 mg/dl (-0.99 to 0.71 mg/dl) and -1.92 mg/dl (-7.72 to 3.88 mg/dl) respectively). The lipid modulating effects of vitamin D supplementation should be further investigated though large-scale, randomized trials with adequate doses which can effectively elevated the active form of vitamin D in plasma and with proper population which has hyperlipemia as an inclusion criterion.
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Affiliation(s)
- Hao Wang
- Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
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Thadhani R. Is calcitriol life-protective for patients with chronic kidney disease? J Am Soc Nephrol 2009; 20:2285-90. [PMID: 19679671 DOI: 10.1681/asn.2009050494] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Affiliation(s)
- Ravi Thadhani
- Renal Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.
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Khajehdehi P, Taheri S. Effect of oral calcitriol pulse therapy on the lipid, calcium, and glucose homeostasis of hemodialysis-patients: its safety in a combination with oral calcium carbonate. J Ren Nutr 2003; 13:78-83. [PMID: 12671829 DOI: 10.1053/jren.2003.50026] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVE To more clearly elucidate the conflicting results that have been obtained after oral calcitriol pulse therapy on lipid, glucose, and calcium levels in hemodialysis (HD) patients, and to determine safety of oral calcitriol pulse therapy in a combination with calcium carbonate. DESIGN A randomized, crossover, placebo-controlled study. SETTING HD centers in 3 teaching university hospitals. PATIENTS Forty-eight chronic HD patients. METHODS HD patients were randomized into 2 groups. Each group (n = 24), in addition to 4.5 g calcium carbonate daily, received either oral calcitriol pulse therapy or placebo twice weekly at the end of HD, sessions for 3 months, after which the 2 therapeutic groups were crossed-over, and for an additional 3 months, the calcitriol group received placebo, and the placebo group was put on calcitriol. Serum triglyceride, total cholesterol, low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), total calcium, alkaline phosphatase, proteins, phosphorus, parathyroid hormone (PTH), blood pH, and glucose were measured at random and at the end of 3 and 6 months of the trial. RESULTS After calcitriol therapy, triglyceride, serum PTH, total alkaline phosphatase, and fasting blood sugar significantly decreased, but total serum calcium significantly increased, whereas other examined parameters remained unchanged compared with the other groups. Calcium, phosphorus, calcium x phosphorus product, PTH levels, and all of these parameters were optimized in 18 (37.5%), 22 (45.8%), 34 (70.8%), 30 (62.5%), and 12 (%25) cases, respectively, in the calcitriol groups. No significant side effect was seen during the trial. CONCLUSION Our findings indicate that short-term oral calcitriol pulse therapy in combination with calcium carbonate is safe and beneficial for metabolic abnormalities of HD patients; however, its safety for prolonged therapy is yet to be proved.
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Affiliation(s)
- Parviz Khajehdehi
- Division of Nephrology, Department of Medicine, Namazee Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
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Kasuga H, Hosogane N, Matsuoka K, Mori I, Sakura Y, Shimakawa K, Shinki T, Suda T, Taketomi S. Characterization of transgenic rats constitutively expressing vitamin D-24-hydroxylase gene. Biochem Biophys Res Commun 2002; 297:1332-8. [PMID: 12372434 DOI: 10.1016/s0006-291x(02)02254-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Vitamin D-24-hydroxylase (CYP24) is one of the enzymes responsible for vitamin D metabolism. CYP24 catalyzes the conversion of 25-hydroxyvitamin D(3) [25(OH)D(3)] to 24,25-dihydroxyvitamin D(3) [24,25(OH)(2)D(3)] in the kidney. CYP24 is also involved in the breakdown of 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)], the active form of vitamin D(3). In this study, we generated transgenic (Tg) rats constitutively expressing CYP24 gene to investigate the biological role of CYP24 in vivo. Surprisingly, the Tg rats showed a significantly low level of plasma 24,25(OH)(2)D(3). Furthermore, the Tg rats developed albuminuria and hyperlipidemia shortly after weaning. The plasma lipid profile revealed that all lipoprotein fractions were elevated in the Tg rats. Also, the Tg rats showed atherosclerotic lesions in the aorta, which greatly progressed with high-fat and high-cholesterol feeding. These unexpected results suggest that CYP24 is involved in functions other than the regulation of vitamin D metabolism.
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Affiliation(s)
- Hisao Kasuga
- Pharmaceutical Research Division, Takeda Chemical Industries, 17-85 Jusohonmachi, 2-chome, Yodokawa-ku, 532-8686, Osaka, Japan
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Querfeld U, Hoffmann MM, Klaus G, Eifinger F, Ackerschott M, Michalk D, Kern PA. Antagonistic effects of vitamin D and parathyroid hormone on lipoprotein lipase in cultured adipocytes. J Am Soc Nephrol 1999; 10:2158-64. [PMID: 10505692 DOI: 10.1681/asn.v10102158] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) (calcitriol) and parathyroid hormone (PTH) on synthesis and secretion of lipoprotein lipase (LPL) were studied in 3T3-L1 adipocytes. Expression of the vitamin D receptor was demonstrated by saturation kinetics with radiolabeled calcitriol. Incubation with calcitriol (10(-8) M) for up to 4 d resulted in a time-dependent significant increase in heparin-releasable LPL activity (LPLa) accompanied by a significant increase in LPL mRNA. In contrast, incubation with intact (1-84) PTH (10(-6) to 10(-9) M) produced a time- and dose-dependent significant decrease in LPLa, but no change in LPL mRNA. The effect of PTH (24-h incubation, 10(-8) M) could be prevented by the calcium channel blocker verapamil. Coincubation with both calcitriol and PTH at equimolar concentration (10(-8) M) resulted in an increase in LPLa and LPL mRNA. These data indicate an antagonistic role for calcitriol and PTH in the regulation of LPL, possibly mediated by intracellular calcium, which may contribute to the alterations in lipoprotein metabolism occurring in uremia.
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Affiliation(s)
- U Querfeld
- University Children's Hospital, Cologne, Germany.
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Affiliation(s)
- Y Nishizawa
- Second Department of Internal Medicine, Osaka City University Medical School, Japan
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Nagode LA, Chew DJ, Podell M. Benefits of calcitriol therapy and serum phosphorus control in dogs and cats with chronic renal failure. Both are essential to prevent of suppress toxic hyperparathyroidism. Vet Clin North Am Small Anim Pract 1996; 26:1293-330. [PMID: 8911021 DOI: 10.1016/s0195-5616(96)50130-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Daily oral calcitriol at low doses is safe and effective in the control of renal secondary hyperparathyroidism in dogs and cats. Low doses of calcitriol are most effective when started early in uremia before the advanced stages of renal secondary hyperparathyroidism. At early stages calcitriol both diminishes PTH synthesis in the parathyroid cells present and prevents the hyperplasia that, if unchecked, results in the most extensive an difficult-to-control hyperparathyroidism. The salutary effects on the dog's or cat's sense of well being, appetite, activity, strength, and lifespan as reported by the veterinarians of our survey are attributed primarily to keeping PTH levels below a toxic threshold. Additionally, some of the benefits achieved by calcitriol are likely a direct consequence of calcitriol interacting with the vitamin D receptor in a wide variety of tissues throughout the body. Phosphorus restriction through a combination of diet and intestinal phosphate binders is important to allow calcitriol therapy to successfully lower PTH levels, but it likely has no direct effects that are independent of interactions involving calcitriol. Phosphorus restriction is also important to minimize chances for adverse tissue mineralization. Calcitriol therapy can be considered for treatment of chronic renal failure after serum phosphorus has been decreased to less than 6.0 mg/dL in patients in whom it was initially elevated. Calcitriol supplementation to dogs and cats with chronic renal failure makes good endocrinologic sense. Calcitriol deficits cause increased PTH and, as these two hormones are designed to maintain calcium and phosphorus homeostasis, the PTH increase is initially adaptive. One of the important effects of PTH is to stimulate additional calcitriol formation as a powerful means to raise blood calcium through increased calcium absorption from the diet. With too great an increase in PTH, however, its effects become harmful to many tissues due to the widespread distribution of the PTH receptor in many cell types that are likely normally responsive only to the paracrine PTH-related peptide that shares the PTH receptor. Exogenous supplemental calcitriol administration allows concentrations of calcitriol in the bloodstream to remain normal without the toxic consequences of excessive PTH secretion that would otherwise be provoked. Studies involving young dogs with subtotal nephrectomy may not parallel those on older dogs and cats with spontaneous chronic renal failure. In particular, higher doses are needed to effect PTH change in these young dogs than we have found necessary for older dogs and cats. Because survey participants agreed most strongly with the idea that their calcitriol-treated dogs and cats were living longer than comparably uremic animals they had treated previously, further studies to evaluate the ability of calcitriol to retard the progression of renal lesions and loss of excretory renal function seem warranted. Additional studies to document the beneficial effects of calcitriol on the many organs adversely affected by excess PTH during uremia are also needed because findings thoroughly documented and proven in humans and rats may not always extrapolate to dogs and cats.
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Affiliation(s)
- L A Nagode
- Department of Veterinary Biosciences, Ohio State University, Columbus, USA
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Kautzky-Willer A, Pacini G, Barnas U, Ludvik B, Streli C, Graf H, Prager R. Intravenous calcitriol normalizes insulin sensitivity in uremic patients. Kidney Int 1995; 47:200-6. [PMID: 7731147 DOI: 10.1038/ki.1995.24] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Recent studies suggest that secondary hyperparathyroidism and/or vitamin D deficiency are responsible for the insulin resistance in chronic renal failure. We investigated the effect of a 12-week intravenous treatment with 1,25 dihydroxycholecalciferol on glucose metabolism in 10 hemodialysis patients compared with 10 healthy control subjects by the frequently-sampled intravenous glucose tolerance test, analyzed with the minimal model technique. Compared to control subjects, the uremic patients featured elevated levels of parathyroid hormone (432 +/- 60 vs. 41 +/- 4 ng/liter, P < 0.001), insulin resistance (insulin sensitivity index, SI: 4.9 +/- 0.8 vs. 9.5 +/- 0.9 min-1/(microU/ml), P < 0.002), increased posthepatic insulin delivery (6.48 +/- 2.48 vs. 2.73 +/- 3.14 nmol/liter in 4 hr, P < 0.001) and a reduced C-peptide fractional clearance (0.033 +/- 0.004 vs. 0.085 +/- 0.009 min-1, P < 0.0002). Following treatment with 1,25 dihydroxycholecalciferol, the parathyroid hormone levels decreased significantly to 237 +/- 30 ng/liter (P < 0.05), the insulin sensitivity index (SI: 9.6 +/- 2.2, P < 0.05) reached a value similar to that of control subjects, and posthepatic insulin delivery decreased to 4.63 +/- 0.83 nmol/liter in 4 hr (P < 0.01), while all the other parameters remained unchanged. In summary, uremic patients with secondary hyperparathyroidism were found to be severely insulin resistant and hyperinsulinemic. Intravenous vitamin D treatment led to a significant reduction of parathyroid hormone levels and to a complete normalization of insulin sensitivity in the hemodialysis patients. Thus, intravenous 1,25 dihydroxycholecalciferol improves insulin resistance in uremic patients, acting per se or by reducing secondary hyperparathyroidism.
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