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Rostamzadeh F, Moosavi-Saeed Y, Yeganeh-Hajahmadi M. Interaction of Klotho and sirtuins. Exp Gerontol 2023; 182:112306. [PMID: 37804921 DOI: 10.1016/j.exger.2023.112306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 09/30/2023] [Accepted: 10/02/2023] [Indexed: 10/09/2023]
Abstract
OBJECTIVE In this article, we review the articles that have reported the interaction between Klotho and sirtuins. RECENT FINDINGS Sirtuins are a family of histone deacetylase enzymes that are considered to be the main regulators of biological processes. This family is one of the essential factors for postponing aging and increasing the life span of organisms. Sirtuins play a role in regulating the function of various cellular processes such as cellular metabolism, oxidative stress, apoptosis, and inflammation. It has also been shown that various diseases are related to these enzymes. Klotho is an anti-aging protein that exists as a membrane protein as well as a soluble circulating form. The membrane type of this protein acts as a co-receptor of the FGF endocrine family. It has been shown that the Klotho gene is related to age-related diseases, including osteoporosis, coronary artery, brain diseases, diabetes, etc. At the same time, it is difficult to separate the actions of Klotho and endocrine FGFs. Several studies have shown that Klotho and sirtuins interact with each other at different regulatory levels. However, it is necessary to carry out more in-vivo investigations to create new windows towards the treatment or prevention of various diseases.
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Affiliation(s)
- Farzaneh Rostamzadeh
- Physiology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Yasamin Moosavi-Saeed
- Endocrinology and Metabolism Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran
| | - Mahboobeh Yeganeh-Hajahmadi
- Cardiovascular Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Science, Kerman, Iran.
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Sugar sweetened beverage consumption is positively associated with Klotho levels at two years of age in LatinX youth. BMC Nutr 2021; 7:22. [PMID: 33888157 PMCID: PMC8063295 DOI: 10.1186/s40795-021-00423-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 03/22/2021] [Indexed: 11/21/2022] Open
Abstract
Background Klotho is an anti-aging protein mainly expressed in the kidneys with a smaller amount expressed in adipose tissue. Klotho effects include roles in reducing oxidative stress, insulin signaling, adipogenesis and glucose metabolism. Few studies have investigated the role of dietary factors such as sugar sweetened beverages (SSBs) on serum α-klotho levels in young children. Methods Data was collected from 60 low-income Latina pregnant women and their infants in San Francisco from birth until 2 years of life and examined for associations between dietary factors and child secreted α-klotho protein levels at 2 years. Results Mean α-klotho levels were 1782.96 ± 874.56 pg/mL at 2 years of age. Any consumption of SSBs was independently associated with increased α-klotho levels (Beta = 682.79, 95%CI 67.50, 1298.09; p = 0.03). Household income ranging from $25,000 to $50,000 was also correlated to higher levels of α-klotho in children compared with lower income levels (<$25,000) (Beta = 1613.35, 95%CI 527.37, 2699.33; p = 0.005). Conclusions The positive association between SSB intake and α-klotho levels at 2 years may reflect higher phosphate levels consistent with SSB intake. Higher socioeconomic status may be a proxy for reduced stress exposure in children, also associated with higher α-klotho levels. Future studies should evaluate the early impact of exposures to SSBs, stress and accelerated aging in children.
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FGF/FGFR Signaling in Hepatocellular Carcinoma: From Carcinogenesis to Recent Therapeutic Intervention. Cancers (Basel) 2021; 13:cancers13061360. [PMID: 33802841 PMCID: PMC8002748 DOI: 10.3390/cancers13061360] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 03/11/2021] [Accepted: 03/13/2021] [Indexed: 12/16/2022] Open
Abstract
Simple Summary As the most common primary liver cancer, HCC is a tricky cancer resistant to systemic therapies. The fibroblast growth factor family and its receptors are gaining more and more attention in various cancers. Noticing an explosion in the number of studies about aberrant FGF/FGFR signaling in HCC being studied, we were encouraged to summarize them. This review discusses how FGF/FGFR signaling influences HCC development and its implications in HCC prediction and target treatment, and combination treatment. Abstract Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, ranking third in cancer deaths worldwide. Over the last decade, several studies have emphasized the development of tyrosine kinase inhibitors (TKIs) to target the aberrant pathways in HCC. However, the outcomes are far from satisfactory due to the increasing resistance and adverse effects. The family of fibroblast growth factor (FGF) and its receptors (FGFR) are involved in various biological processes, including embryogenesis, morphogenesis, wound repair, and cell growth. The aberrant FGF/FGFR signaling is also observed in multiple cancers, including HCC. Anti-FGF/FGFR provides delightful benefits for cancer patients, especially those with FGF signaling alteration. More and more multi-kinase inhibitors targeting FGF signaling, pan-FGFR inhibitors, and selective FGFR inhibitors are now under preclinical and clinical investigation. This review summarizes the aberrant FGF/FGFR signaling in HCC initiating, development and treatment status, and provide new insights into the treatment of HCC.
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Hanna RM, Ferrey A, Rhee CM, Kalantar-Zadeh K. Renal-Cerebral Pathophysiology: The Interplay Between Chronic Kidney Disease and Cerebrovascular Disease. J Stroke Cerebrovasc Dis 2020; 30:105461. [PMID: 33199089 DOI: 10.1016/j.jstrokecerebrovasdis.2020.105461] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 11/01/2020] [Accepted: 11/03/2020] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVES Cerebrovascular disease has increasingly been linked to overall vascular health. Pathologic conditions like diabetes, hypertension, and kidney disease have been shown to affect brain health and cerebrovascular and nervous systems. Acute kidney injury (AKI) and chronic Kidney Disease (CKD) represent a variety of vascular insults that can adversely affect cerebral health. Hypertension, fluctuations in blood pressure, and diabetic vasculopathy are known risk factors for cerebrovascular disease associated with CKD. Other emerging areas of interest include endothelial dysfunction, vascular calcification due to calcium and phosphorus metabolism dysregulation, and uremic neuropathy present the next frontier of investigation in CKD and cerebrovascular health. METHODS It has become apparent that the interrelation of AKI and CKD with vascular health, chemical homeostasis, and hormonal regulation upset many aspects of cerebral health and functioning. Stroke is an obvious connection, with CKD patients demonstrating a higher proclivity for cerebrovascular accidents. Cerebral bleeding risk, uremic neuropathies, sodium dysregulation with impacts on nervous system, vascular calcification, and endothelial dysfunction are the next salient areas of research that are likely to reveal key breakthroughs in renal-cerebral pathophysiology. RESULTS In this review nephrological definition are discussed in a neuro-centric manner, and the areas of key overlap between CKD and cerebrovascular pathology are discussed. The multifaceted effects of renal function on the health of the brain are also examined. CONCLUSION This review article aims to create the background for ongoing and future neurological-nephrological collaboration on understanding the special challenges in caring for patients with cerebrovascular disease who also have CKD.
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Affiliation(s)
- Ramy M Hanna
- Division of Nephrology, Hypertension and Kidney Transplantation, Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California, Irvine, School of Medicine, 101 The City Drive South, City Tower, Suite 400, Orange, CA 92868, USA.
| | - Antoney Ferrey
- Division of Nephrology, Hypertension and Kidney Transplantation, Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California, Irvine, School of Medicine, 101 The City Drive South, City Tower, Suite 400, Orange, CA 92868, USA.
| | - Connie M Rhee
- Division of Nephrology, Hypertension and Kidney Transplantation, Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California, Irvine, School of Medicine, 101 The City Drive South, City Tower, Suite 400, Orange, CA 92868, USA.
| | - Kamyar Kalantar-Zadeh
- Division of Nephrology, Hypertension and Kidney Transplantation, Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California, Irvine, School of Medicine, 101 The City Drive South, City Tower, Suite 400, Orange, CA 92868, USA.
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Tørnqvist-Johnsen C, Schnabel T, Gow AG, Del-Pozo J, Milne E, Macklin V, Fisher C, Handel I, Mellanby RJ. Investigation of the relationship between ionised and total calcium in dogs with ionised hypercalcaemia. J Small Anim Pract 2020; 61:247-252. [PMID: 32043601 DOI: 10.1111/jsap.13109] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 12/01/2019] [Accepted: 12/16/2019] [Indexed: 02/02/2023]
Abstract
OBJECTIVES To investigate the relationship between total and ionised calcium concentrations in dogs with ionised hypercalcaemia and to evaluate how albumin influences this relationship. METHODS Initially, a reference interval for ionised and total calcium was established using a large population of healthy adult dogs. Our teaching hospital clinical database was searched to identify adult dogs with ionised hypercalcaemia between 2012 and 2017, a time frame when the same sample handling and analysis protocols were in place as for the healthy reference interval population. The relationship between ionised and total calcium concentrations was then examined in the ionised hypercalcaemia population. RESULTS Based on biochemical analysis of 351 healthy adult dogs, a reference interval of 1.18 to 1.53 mmol/L for ionised calcium and 2.24 to 2.85 mmol/L for total calcium was established. Using these reference intervals, 63 dogs with ionised hypercalcaemia were identified, of which 23 did not have total hypercalcaemia. Only seven of the 23 dogs with ionised hypercalcaemia and total calcium below the upper limit of the reference interval had hypoalbuminemia. The majority of dogs with ionised hypercalcemia and normal total calcium had a modest increase in ionised calcium. CLINICAL SIGNIFICANCE If relying on total calcium alone, more than one third of dogs with ionised hypercalcaemia will be classified as normocalcaemic and the majority of these dogs had normal serum albumin.
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Affiliation(s)
- C Tørnqvist-Johnsen
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Midlothian, UK
| | - T Schnabel
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Midlothian, UK
| | - A G Gow
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Midlothian, UK
| | - J Del-Pozo
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Midlothian, UK
| | - E Milne
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Midlothian, UK
| | - V Macklin
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Midlothian, UK
| | - C Fisher
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Midlothian, UK
| | - I Handel
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Midlothian, UK
| | - R J Mellanby
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Midlothian, UK
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Tótoli C, Carvalho AB, Ammirati AL, Draibe SA, Canziani MEF. Associated factors related to chronic kidney disease progression in elderly patients. PLoS One 2019; 14:e0219956. [PMID: 31335919 PMCID: PMC6650050 DOI: 10.1371/journal.pone.0219956] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 07/06/2019] [Indexed: 01/10/2023] Open
Abstract
Background Chronic Kidney Disease (CKD) is a worldwide public health problem. The prevalence of CKD is rising especially in elderly, as consequence of population-ageing related to socioeconomic development and better life expectancy. There are scarce studies evaluating CKD progression and its associated factors in elderly patients. Methods This is a retrospective observational study including 340 patients (≥ 65 years old) CKD stages 3a–5 non-dialysis, incidents in an outpatient CKD clinic, followed by 2.1 years. CKD progression was assessed by the slope of eGFR calculated by CKD-EPI and BIS 1 equations. The patients were divided in progressor and non-progressor groups (eGFR slope < or ≥ 0 mL/min/1.73 m2/year, respectively). Results Kidney function declined in 193 (57%) patients. In this group, the progression rate was -2.83 (-5.1 / -1.1) mL /min /1.73 m2 /year. Compared to non progressor, the progressor patients were younger [72 (69–78) vs. 76 (69–80) years; p = 0.02]; had higher proportion of diabetic nephropathy, higher serum phosphorus [3.8 (3.3–4.1) vs. 3.5 (3.9–4.1) mg/dL; p = 0.04] and proteinuria [0.10 (0–0.9 vs. 0 (0–0.3)] g/L; p = 0.007)] at the admission. In the logistic regression analysis adjusted for gender and eGFR, proteinuria was independently associated with CKD progression [OR (Odds Ratio) (1.83; 95% CI, 1.17–2.86; p < 0.01)]. Conclusion CKD progression was observed in the majority of elderly CKD patients and proteinuria was the most important factor associated to the decline of kidney function in this population.
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Affiliation(s)
- Cláudia Tótoli
- Department of Medicine, Division of Nephrology, Federal University of São Paulo, São Paulo, Brazil
| | - Aluizio Barbosa Carvalho
- Department of Medicine, Division of Nephrology, Federal University of São Paulo, São Paulo, Brazil
| | - Adriano Luiz Ammirati
- Department of Medicine, Division of Nephrology, Federal University of São Paulo, São Paulo, Brazil
| | - Sergio Antônio Draibe
- Department of Medicine, Division of Nephrology, Federal University of São Paulo, São Paulo, Brazil
| | - Maria Eugênia F. Canziani
- Department of Medicine, Division of Nephrology, Federal University of São Paulo, São Paulo, Brazil
- * E-mail:
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Mazzaferro V, El-Rayes BF, Droz Dit Busset M, Cotsoglou C, Harris WP, Damjanov N, Masi G, Rimassa L, Personeni N, Braiteh F, Zagonel V, Papadopoulos KP, Hall T, Wang Y, Schwartz B, Kazakin J, Bhoori S, de Braud F, Shaib WL. Derazantinib (ARQ 087) in advanced or inoperable FGFR2 gene fusion-positive intrahepatic cholangiocarcinoma. Br J Cancer 2019; 120:165-171. [PMID: 30420614 PMCID: PMC6342954 DOI: 10.1038/s41416-018-0334-0] [Citation(s) in RCA: 259] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 10/19/2018] [Accepted: 10/23/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Next-generation sequencing has identified actionable genetic aberrations in intrahepatic cholangiocarcinomas (iCCA), including the fibroblast growth factor receptor 2 (FGFR2) fusions. Derazantinib (ARQ 087), an orally bioavailable, multi-kinase inhibitor with potent pan-FGFR activity, has shown preliminary therapeutic activity against FGFR2 fusion-positive iCCA. METHODS This multicentre, phase 1/2, open-label study enrolled adult patients with unresectable iCCA with FGFR2 fusion, who progressed, were intolerant or not eligible to first-line chemotherapy (NCT01752920). Subjects received derazantinib in continuous daily doses. Tumour response was assessed according to RECIST 1.1 every 8 weeks. RESULTS Twenty-nine patients (18 women/11 men; median age, 58.7 years), 2 treatment-naive and 27 who progressed after at least one prior systemic therapy, were enrolled. Overall response rate was 20.7%, disease control rate was 82.8%. Estimated median progression-free survival was 5.7 months (95% CI: 4.04-9.2 months). Treatment-related adverse events (AE) were observed in 27 patients (93.1%, all grades), including asthenia/fatigue (69.0%), eye toxicity (41.4%), and hyperphosphatemia (75.9%). Grade ≥ 3 AEs occurred in 8 patients (27.6%). CONCLUSION Derazantinib demonstrated encouraging anti-tumour activity and a manageable safety profile in patients with advanced, unresectable iCCA with FGFR2 fusion who progressed after chemotherapy. A pivotal trial of derazantinib in iCCA is ongoing (NCT03230318).
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Affiliation(s)
- Vincenzo Mazzaferro
- Department of Surgery and Oncology, Istituto Nazionale Tumori IRCCS, Milan, Italy.
- University of Milan, Milan, Italy.
| | | | | | - Christian Cotsoglou
- Department of Surgery and Oncology, Istituto Nazionale Tumori IRCCS, Milan, Italy
| | | | - Nevena Damjanov
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA, USA
| | - Gianluca Masi
- Department of Oncology, Pisa University Hospital, Pisa, Italy
| | - Lorenza Rimassa
- Humanitas Cancer Center, Humanitas Clinical and Research Center, Rozzano, Milan, Italy
| | - Nicola Personeni
- Humanitas Cancer Center, Humanitas Clinical and Research Center, Rozzano, Milan, Italy
- Department of Medical Biosciences, Humanitas University, Pieve Emanuele, Milan, Italy
| | - Fadi Braiteh
- Medical Oncology, Comprehensive Cancer Centers of Nevada, Las Vegas, NV, USA
| | | | | | | | | | | | | | - Sherrie Bhoori
- Department of Surgery and Oncology, Istituto Nazionale Tumori IRCCS, Milan, Italy
| | - Filippo de Braud
- Department of Surgery and Oncology, Istituto Nazionale Tumori IRCCS, Milan, Italy
- University of Milan, Milan, Italy
| | - Walid L Shaib
- Winship Cancer Institute, Emory University, Atlanta, GA, USA
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Moulin B, Ponchon T. A comparative review of use of sulphate and phosphate salts for colonoscopy preparations and their potential for nephrotoxicity. Endosc Int Open 2018; 6:E1206-E1213. [PMID: 30302378 PMCID: PMC6175689 DOI: 10.1055/a-0581-8723] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 11/28/2017] [Indexed: 12/23/2022] Open
Abstract
Background and study aims Colonoscopy is a widely used diagnostic procedure which requires prior cleansing of the bowel. Many different bowel cleansing preparations have been developed, all of which have specific advantages and disadvantages. This review compares two low-volume high-osmolarity bowel cleansing preparations, oral phosphate salts and oral sulphate salts, with a particular focus on risk of nephrotoxicity. Patients and methods An electronic search of the Medline database was performed using the search terms "(phosphates OR sulfates) AND cathartics [MeSH Term] AND kidney" restricted to humans with a cut-off date of December 31, 2016. Results Introduction of oral phosphate salts offered the advantage of low intake volume and low risk of bowel irritation compared to previous options. However, phosphate salts have been associated with renal toxicity (acute phosphate nephropathy [APN]), thought to arise due to perturbations of calcium and phosphate homeostasis as a consequence of increases in serum phosphate. This results in high concentrations of calcium phosphate in the distal tubule and collecting ducts of the kidney, where it may precipitate. Although APN is rare, it may lead to permanent kidney damage. For this reason, phosphate salts are contraindicated in vulnerable patient groups. As an alternative to phosphate salts, oral sulphate salts have recently been introduced. Because sulphate absorption from the intestinal tract is saturable, serum sulphate concentrations increase only minimally after ingestion. Furthermore, excretion of sulphate in the kidney is not accompanied by calcium excretion and urine calcium levels are unchanged. For these theoretical reasons, use of sulphate salts as bowel cleansing solutions is not expected to lead to calcium precipitation in the nephron. Conclusions Oral phosphate salts are no longer recommended for routine use as bowel cleansing preparations as they carry significant risk of kidney damage and a safer alternative is available in the form of oral sulphate solutions. To date, use of sulphate salts has not been associated with elevations in serum creatinine or other markers of renal impairment, nor with clinical manifestations of kidney injury. Nonetheless, experience with sulphate salts in everyday practice is limited and physicians should be vigilant in detecting potential safety issues.
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Affiliation(s)
- Bruno Moulin
- Nephrology Department, Strasbourg University Hospital, 67091 Strasbourg, France,Corresponding author Pr. Bruno Moulin Service de néphrologie et transplantation rénaleCHU de Strasbourg – Nouvel Hôpital Civil1, place de l'HôpitalBP 42667091 Strasbourg CedexFrance+33 3 69 55 17 21
| | - Thierry Ponchon
- Hepatogastroenterology Department, Edouard Herriot Hospital, 69000 Lyon, France
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Stremke ER, Hill Gallant KM. Intestinal Phosphorus Absorption in Chronic Kidney Disease. Nutrients 2018; 10:E1364. [PMID: 30249044 PMCID: PMC6213936 DOI: 10.3390/nu10101364] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 09/17/2018] [Accepted: 09/19/2018] [Indexed: 02/06/2023] Open
Abstract
Chronic kidney disease (CKD) affects approximately 10% of adults worldwide. Dysregulation of phosphorus homeostasis which occurs in CKD leads to development of CKD-Mineral Bone Disorder (CKD-MBD) and contributes to increased morbidity and mortality in these patients. Phosphorus is regulated by multiple hormones (parathyroid hormone (PTH), 1,25-dihyxdroxyvitamin D (1,25D), and fibroblast growth factor 23 (FGF23)) and tissues (kidney, intestine, parathyroid glands, and bone) to maintain homeostasis. In health, the kidneys are the major site of regulation for phosphorus homeostasis. However, as kidney function declines, the ability of the kidneys to adequately excrete phosphorus is reduced. The hormonal changes that occur with CKD would suggest that the intestine should compensate for impaired renal phosphorus excretion by reducing fractional intestinal phosphorus absorption. However, limited studies in CKD animal models and patients with CKD suggest that there may be a break in this homeostatic response where the intestine fails to compensate. As many existing therapies for phosphate management in CKD are aimed at reducing absolute intestinal phosphorus absorption, better understanding of the factors that influence fractional and absolute absorption, the mechanism by which intestinal phosphate absorption occurs, and how CKD modifies these is a much-needed area of study.
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Affiliation(s)
- Elizabeth R Stremke
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA.
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Behringer V, Stevens JMG, Deschner T, Sonnweber R, Hohmann G. Aging and sex affect soluble alpha klotho levels in bonobos and chimpanzees. Front Zool 2018; 15:35. [PMID: 30250491 PMCID: PMC6146871 DOI: 10.1186/s12983-018-0282-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 09/07/2018] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Throughout life, physiological homeostasis is challenged and the capacity to cope with such challenges declines with increasing age. In many species, sex differences exist in life expectancy. Sex-specific differences have been related to extrinsic factors like mate competition and/or intrinsic proximate mechanisms such as hormonal changes. In humans, an intrinsic factor related to aging is soluble alpha klotho (α-Kl). Both sexes show an age-related decline in α-Kl, but throughout life women have higher levels than men of the same age. Sex differences in α-Kl have been linked to a shorter lifespan, as well as to specific morbidity factors such as atherosclerosis and arteries calcifications. In non-human animals, information on α-Kl levels is rare and restricted to experimental work. Our cross-sectional study is the first on α-Kl levels in two long-lived species: bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). As in most mammals, female bonobos and chimpanzees have longer life expectancy than males. METHODS We measured serum α-Kl levels of 140 subjects from 16 zoos with an ELISA to examine if α-Kl levels reflect this difference in life expectancy. RESULTS In both species and in both sexes, α-Kl levels declined with age suggesting that this marker has potential for aging studies beyond humans. We also found species-specific differences. Adult female bonobos had higher α-Kl levels than males, a difference that corresponds to the pattern found in humans. In chimpanzees, we found the opposite: males had higher α-Kl levels than females. CONCLUSION We suggest that contrasting sex differences in adult α-Kl levels mirror the dominance relations between females and males of the two Pan species; and that this might be related to corresponding sex differences in their exposure to stress. In humans, higher cortisol levels were found to be related to lower α-Kl levels. We conclude that there is great potential for studying aging processes in hominoids, and perhaps also in other non-human primates, by measuring α-Kl levels. To better understand the causes for sex differences in this aging marker, consideration of behavioural parameters such as competition and stress exposure will be required as well as other physiological markers.
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Affiliation(s)
- V. Behringer
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - J. M. G. Stevens
- Antwerp Zoo Centre for Research and Conservation, Royal Zoological Society of Antwerp, K. Astridplein 26, 2018 Antwerp, Belgium
- Behavioral Ecology and Ecophysiology, Department of Biology, University of Antwerp, 2610 Wilrijk, Belgium
| | - T. Deschner
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - R. Sonnweber
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - G. Hohmann
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
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Yoshikawa R, Yamamoto H, Nakahashi O, Kagawa T, Tajiri M, Nakao M, Fukuda S, Arai H, Masuda M, Iwano M, Takeda E, Taketani Y. The age-related changes of dietary phosphate responsiveness in plasma 1,25-dihydroxyvitamin D levels and renal Cyp27b1 and Cyp24a1 gene expression is associated with renal α-Klotho gene expression in mice. J Clin Biochem Nutr 2017; 62:68-74. [PMID: 29371756 PMCID: PMC5773827 DOI: 10.3164/jcbn.17-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 08/04/2017] [Indexed: 12/21/2022] Open
Abstract
In this study, we investigated the relationship between age-related changes in renal α-Klotho gene expression, vitamin D metabolism and the responsiveness of dietary phosphate in 1, 2 and 13 month-old mice fed a high phosphate (phosphate 1.2%) diet or low phosphate (phosphate 0.02%) diet for 5 days. We found that 1,25-dihydroxyvitamin D levels in plasma were significantly lower in the high phosphate group than the low phosphate group for 1 and 2 month-old mice, but not 13 month-old mice. In addition, in the high phosphate group plasma 1,25-dihydroxyvitamin D levels were decreased in 2 month-old mice relative to 1 month-old mice, but 13 month-old mice had higher levels than 2 month-old mice. In fact, plasma 1,25-dihydroxyvitamin D levels showed a significant correlation with vitamin D metabolism gene Cyp27b1 and Cyp24a1 mRNA expression in the high phosphate group. Interestingly, renal α-Klotho mRNA and protein levels were significant change with age. Furthermore, α-Klotho mRNA expression showed a significant negative correlation with plasma 1,25-dihydroxyvitamin D levels in the high phosphate group. Our results suggest that age-related alterations in renal α-Klotho expression could affect the responsiveness of dietary phosphate to vitamin D metabolism.
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Affiliation(s)
- Ryouhei Yoshikawa
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
| | - Hironori Yamamoto
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan.,Department of Health and Nutrition, Faculty of Human Life, Jin-ai University, 3-1-1 Ohde-cho, Echizen-city, Fukui 915-8586, Japan.,Department of Nephrology, Faculty of Medical Sciences, University of Fukui, 23-3 Matsuoka Shimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui 910-1193, Japan
| | - Otoki Nakahashi
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan.,Division of Functional Food Chemistry, Institute for Health Science, Tokushima Bunri University, 180 Nishihamahoji, Yamashiro-cho, Tokushima 770-8514, Japan
| | - Tomohiro Kagawa
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
| | - Mari Tajiri
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
| | - Mari Nakao
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
| | - Shiori Fukuda
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
| | - Hidekazu Arai
- Laboratory of Clinical Nutrition and Management, Graduate School of Nutritional and Environmental Sciences, The University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Masashi Masuda
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
| | - Masayuki Iwano
- Department of Nephrology, Faculty of Medical Sciences, University of Fukui, 23-3 Matsuoka Shimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui 910-1193, Japan
| | - Eiji Takeda
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
| | - Yutaka Taketani
- Department of Clinical Nutrition and Food Management, Institute of Biomedical Sciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
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12
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Papadopoulos KP, El-Rayes BF, Tolcher AW, Patnaik A, Rasco DW, Harvey RD, LoRusso PM, Sachdev JC, Abbadessa G, Savage RE, Hall T, Schwartz B, Wang Y, Kazakin J, Shaib WL. A Phase 1 study of ARQ 087, an oral pan-FGFR inhibitor in patients with advanced solid tumours. Br J Cancer 2017; 117:1592-1599. [PMID: 28972963 PMCID: PMC5729432 DOI: 10.1038/bjc.2017.330] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/22/2017] [Accepted: 08/29/2017] [Indexed: 12/15/2022] Open
Abstract
Background: ARQ 087 is an orally administered pan-FGFR inhibitor with multi-kinase activity. This Phase 1 study evaluated safety, pharmacokinetics, and pharmacodynamics of ARQ 087 and defined the recommended Phase 2 dose (RP2D). Methods: Patients with advanced solid tumours received ARQ 087 administered initially at 25 mg every other day and dose-escalated from 25 to 425 mg daily (QD) continuous dosing. FGF19, 21, 23, and serum phosphate were assessed as potential biomarkers of target engagement. Results: 80 patients were enrolled, 61 in dose-escalation/food-effect cohorts and 19 with pre-defined tumour types in the expansion cohort. The most common ARQ 087-related adverse events were fatigue (49%), nausea (46%), aspartate aminotransferase (AST) increase (30%), and diarrhoea (23%). Four patients (5%) experienced grade 1 treatment-related hyperphosphataemia. Dose-limiting toxicity was reversible grade 3 AST increase. The RP2D was 300 mg QD. Pharmacokinetics were linear and dose-proportional from 25 to 325 mg QD, and were unaffected by food. Statistically significant changes (P-value<0.05) suggest phosphate and FGF19 levels as markers of target engagement. In 18 evaluable patients with FGFR genetic alterations, 3 confirmed partial responses (two intrahepatic cholangiocarcinomas (iCCA) with FGFR2 fusions and one urothelial cancer with FGFR2 and FGF19 amplification) and two durable stable disease at ⩾16 weeks with tumour reduction (FGFR2 fusion-positive iCCA and adrenocortical carcinoma with FGFR1 amplification) were observed. Conclusions: ARQ 087 had manageable toxicity at the RP2D of 300 mg QD, showed pharmacodynamics effects, and achieved objective responses, notably in patients with FGFR2 genetic alterations.
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Affiliation(s)
- K P Papadopoulos
- South Texas Accelerated Research Therapeutics, 4383 Medical Drive, San Antonio, TX 78229, USA
| | - B F El-Rayes
- Winship Cancer Institute of Emory University, 1365-C Clifton Road NE, Atlanta, GA 30322, USA
| | - A W Tolcher
- South Texas Accelerated Research Therapeutics, 4383 Medical Drive, San Antonio, TX 78229, USA
| | - A Patnaik
- South Texas Accelerated Research Therapeutics, 4383 Medical Drive, San Antonio, TX 78229, USA
| | - D W Rasco
- South Texas Accelerated Research Therapeutics, 4383 Medical Drive, San Antonio, TX 78229, USA
| | - R D Harvey
- Winship Cancer Institute of Emory University, 1365-C Clifton Road NE, Atlanta, GA 30322, USA
| | - P M LoRusso
- Karmanos Cancer Institute, 4206-4th Floor HWCRC, 4100 John R, Detroit, MI 48201, USA
| | - J C Sachdev
- Virginia G. Piper Cancer Center, Scottsdale Healthcare, 10460N 92nd Street, Scottsdale, AZ 85258, USA
| | - G Abbadessa
- ArQule, Inc. One Wall Street, Burlington, MA 01803, USA
| | - R E Savage
- ArQule, Inc. One Wall Street, Burlington, MA 01803, USA
| | - T Hall
- ArQule, Inc. One Wall Street, Burlington, MA 01803, USA
| | - B Schwartz
- ArQule, Inc. One Wall Street, Burlington, MA 01803, USA
| | - Y Wang
- ArQule, Inc. One Wall Street, Burlington, MA 01803, USA
| | - J Kazakin
- ArQule, Inc. One Wall Street, Burlington, MA 01803, USA
| | - W L Shaib
- Winship Cancer Institute of Emory University, 1365-C Clifton Road NE, Atlanta, GA 30322, USA
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13
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Fakhar M, Rashid S. Targeted inhibition of Klotho binding to fibroblast growth factor 23 prevents hypophosphetemia. J Mol Graph Model 2017; 75:9-19. [PMID: 28501532 DOI: 10.1016/j.jmgm.2017.04.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Revised: 04/13/2017] [Accepted: 04/18/2017] [Indexed: 02/08/2023]
Abstract
Klotho is a transmembrane protein which plays significant role in the pathogenesis of phosphate ion (Pi)-related disorders. Pi accumulation in human kidney tissues results in the major metabolic disorders due to malfunctioning of Klotho-FGFR1-FGF23 trimeric complex. The potential role of Klotho in Pi metabolism was elaborated through modeling and interaction analysis of glycosyl hydrolase (GS1 and GS2) domains with Fibroblast growth factor 23 (FGF23). In order to inhibit the association of Klotho and FGF23, binding patterns of three reported hits (N-(2-chlorophenyl)-1H-indole-3-carboxamide, N-[2-(1-cyclohexen-1-yl)ethyl]-6,7,8,9-tetrahydropyrido[1,2-e]purin-4-amine and 2-(1-propyl)amino-11-chlorothiazolo[5,4-a]acridine) were evaluated through molecular docking analysis. These inhibitors effectively targeted both GS1 and GS2 domains of Klotho at the similar sites required for FGF23 binding. To further characterize the comparative binding profile of these compounds, molecular dynamics simulation assays were performed. Taken together, current study emphasizes that Klotho may be anticipated as a target molecule in familial hypophosphatemic rickets and mentioned compounds may prove to be effective therapeutic targets against hypophosphetemia induced disorders.
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Affiliation(s)
- Muhammad Fakhar
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Sajid Rashid
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan.
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14
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Matsubara T, Miyaki A, Akazawa N, Choi Y, Ra SG, Tanahashi K, Kumagai H, Oikawa S, Maeda S. Aerobic exercise training increases plasma Klotho levels and reduces arterial stiffness in postmenopausal women. Am J Physiol Heart Circ Physiol 2013; 306:H348-55. [PMID: 24322608 DOI: 10.1152/ajpheart.00429.2013] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Klotho gene is a suppressor of the aging phenomena, and the secretion as well as the circulation of Klotho proteins decrease with aging. Although habitual exercise has antiaging effects (e.g., a decrease in arterial stiffness), the relationship between Klotho and habitual exercise remains unclear. In the present study, we investigated the effect of habitual exercise on Klotho, with a particular focus on arterial stiffness. First, we examined the correlation between plasma Klotho concentration and arterial stiffness (carotid artery compliance and β-stiffness index) or aerobic exercise capacity [oxygen uptake at ventilatory threshold (VT)] in 69 healthy, postmenopausal women (50-76 years old) by conducting a cross-sectional study. Second, we tested the effects of aerobic exercise training on plasma Klotho concentrations and arterial stiffness. A total of 19 healthy, postmenopausal women (50-76 years old) were divided into two groups: control group and exercise group. The exercise group completed 12 wk of moderate aerobic exercise training. In the cross-sectional study, plasma Klotho concentrations positively correlated with carotid artery compliance and VT and negatively correlated with the β-stiffness index. In the interventional study, aerobic exercise training increased plasma Klotho concentrations and carotid artery compliance and decreased the β-stiffness index. Moreover, the changes in plasma Klotho concentration and arterial stiffness were found to be correlated. These results suggest a possible role for secreted Klotho in the exercise-induced modulation of arterial stiffness.
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Affiliation(s)
- Tomoko Matsubara
- Division of Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
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15
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Christakos S, Seth T, Hirsch J, Porta A, Moulas A, Dhawan P. Vitamin D Biology Revealed Through the Study of Knockout and Transgenic Mouse Models. Annu Rev Nutr 2013; 33:71-85. [DOI: 10.1146/annurev-nutr-071812-161249] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sylvia Christakos
- Department of Biochemistry and Molecular Biology, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey 07103;
| | - Tanya Seth
- Department of Biochemistry and Molecular Biology, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey 07103;
| | - Jennifer Hirsch
- Department of Biochemistry and Molecular Biology, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey 07103;
| | - Angela Porta
- Department of Biochemistry and Molecular Biology, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey 07103;
| | - Anargyros Moulas
- Department of Biochemistry and Molecular Biology, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey 07103;
| | - Puneet Dhawan
- Department of Biochemistry and Molecular Biology, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey 07103;
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16
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Abstract
PURPOSE OF REVIEW The klotho gene was originally identified as a putative aging-suppressor gene in mice that extended life span when overexpressed and induced a premature aging syndrome when disrupted. Subsequently, it became clear that the Klotho family of membrane proteins function as obligate co-receptors for endocrine fibroblast growth factors (FGFs) that regulate various metabolic processes. This review focuses on the Klotho-FGF23 endocrine system that maintains phosphate (Pi) homeostasis, and discusses the mechanism of action and the potential contribution of Klotho deficiency to acute kidney injury (AKI), chronic kidney disease (CKD) and cancer. RECENT FINDINGS Klotho functions as a receptor for the phosphaturic hormone FGF23. Klotho deficiency induces resistance to FGF23 and predisposition to Pi retention, which represents a critical feature of pathophysiology of CKD. The extracellular domain of Klotho protein is subject to ectodomain shedding and released into the blood and urine. Secreted Klotho functions as a humoral factor that inhibits AKI, vascular calcification, renal fibrosis, and cancer metastasis in an FGF23-independent manner. SUMMARY Various factors that affect Klotho expression have been identified. Prevention of Klotho decline and supplementation of Klotho can be a novel therapeutic strategy for many age-related diseases.
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17
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Abstract
A disproportionate expansion of white adipose tissue and abnormal recruitment of adipogenic precursor cells can not only lead to obesity but also impair glucose metabolism, which are both common causes of insulin resistance and diabetes mellitus. The development of novel and effective therapeutic strategies to slow the progression of obesity, diabetes mellitus and their associated complications will require improved understanding of adipogenesis and glucose metabolism. Klotho might have a role in adipocyte maturation and systemic glucose metabolism. Klotho increases adipocyte differentiation in vitro, and mice that lack Klotho activity are lean owing to reduced white adipose tissue accumulation; moreover, mice that lack the Kl gene (which encodes Klotho) are resistant to obesity induced by a high-fat diet. Knockout of Kl in leptin-deficient Lep(ob/ob) mice reduces obesity and increases insulin sensitivity, which lowers blood glucose levels. Energy metabolism might also be influenced by Klotho. However, further studies are needed to explore the possibility that Klotho could be a novel therapeutic target to reduce obesity and related complications, and to determine whether and how Klotho might influence the regulation and function of a related protein, β-Klotho, which is also involved in energy metabolism.
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Affiliation(s)
- M Shawkat Razzaque
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Research and Education Building, Room 304, 190 Longwood Avenue, Boston, MA 02115, USA.
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18
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de Paula FJA, Rosen CJ. Vitamin D safety and requirements. Arch Biochem Biophys 2011; 523:64-72. [PMID: 22179017 DOI: 10.1016/j.abb.2011.12.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 11/30/2011] [Accepted: 12/02/2011] [Indexed: 12/22/2022]
Abstract
Vitamin D an ancient secosteroid is essential for mineral homeostasis, bone remodeling, immune modulation, and energy metabolism. Recently, debates have emerged about the daily vitamin D requirements for healthy and elderly adults, the safety and efficacy of long term supplementation and the role of vitamin D deficiency in several chronic disease states. Since this molecule acts as both a vitamin and a hormone, it should not be surprising that the effects of supplementation are multi-faceted and complex. Yet despite significant progress in the last decade, our understanding of vitamin D physiology and the clinical relevance of low circulating levels of this vitamin remains incomplete. The present review provides the reader with a comprehensive and up-to-date understanding of vitamin D requirements and safety. It also raises some provocative research questions.
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Affiliation(s)
- Francisco J A de Paula
- Department of Internal Medicine, School of Medicine of Ribeirão Preto, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, 14049-900 SP, Brazil.
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19
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Razzaque MS. Osteo-renal regulation of systemic phosphate metabolism. IUBMB Life 2011; 63:240-7. [PMID: 21438115 DOI: 10.1002/iub.437] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 01/29/2011] [Indexed: 01/29/2023]
Abstract
Impaired kidney function and subsequent skeletal responses play a critical role in disrupting phosphate balance in chronic kidney disease (CKD) patients with mineral and bone disorder (CKD-MBD). In patients with CKD-MBD, the inability of the kidney to maintain normal mineral ion balance affects bone remodeling to induce skeletal fracture and extraskeletal vascular calcification. In physiological conditions, bone-derived fibroblast growth factor 23 (FGF23) acts on the kidney to reduce serum phosphate and 1,25-dihydroxyvitamin D levels. In humans, increased bioactivity of FGF23 leads to increased urinary phosphate excretion, which induces hypophosphatemic diseases (e.g., rickets/osteomalacia). However, reduced FGF23 activity is associated with hyperphosphatemic diseases (e.g., tumoral calcinosis). In patients with CKD, high serum levels of FGF23 fail to reduce serum phosphate levels and lead to numerous complications, including vascular calcification, one of the important determinants of mortality of CKD-MBD patients. Of particular significance, molecular, biochemical and morphological changes in patients with CKD-MBD are mostly due to osteo-renal dysregulation of mineral ion metabolism. Furthermore, hyperphosphatemia can partly contribute to the development of secondary hyperparathyroidism in patients with CKD-MBD. Relatively new pharmacological agents including sevelamer hydrochloride, calcitriol analogs and cinacalcet hydrochloride are used either alone, or in combination, to minimize hyperphosphatemia and hyperparathyroidism associated complications to improve morbidity and mortality of CKD-MBD patients. This article will briefly summarize how osteo-renal miscommunication can induce phosphate toxicity, resulting in extensive tissue injuries.
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Affiliation(s)
- Mohammed Shawkat Razzaque
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA.
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20
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Forster I, Hernando N, Sorribas V, Werner A. Phosphate transporters in renal, gastrointestinal, and other tissues. Adv Chronic Kidney Dis 2011; 18:63-76. [PMID: 21406290 DOI: 10.1053/j.ackd.2011.01.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 01/17/2011] [Accepted: 01/18/2011] [Indexed: 11/11/2022]
Abstract
Inorganic phosphate (Pi) is essential for all living organisms. Bound to organic molecules, Pi fulfills structural, metabolic, and signaling tasks. Therefore, cell growth and maintenance depends on efficient transport of Pi across cellular membranes into the intracellular space. Uptake of Pi requires energy because the substrate is transported against its electrochemical gradient. Till recently, 2 major families of physiologically relevant Pi-specific transporters have been identified: the solute carrier families Slc34 and Slc20. Interestingly, phylogenetic links can be detected between prokaryotic and eukaryotic transporters in both families. Because less complex model organisms are often instrumental in establishing paradigms for protein function in human beings, a brief assessment of Slc34 and Slc20 phylogeny is of interest.
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