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Chan GCK, Ng JKC, Szeto CC, Chow KM. Effects on calcium phosphate homeostasis after sodium-glucose cotransporter 2 inhibitor in patients with advanced chronic kidney disease and type 2 diabetes mellitus. Diabetes Res Clin Pract 2024; 216:111818. [PMID: 39128564 DOI: 10.1016/j.diabres.2024.111818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2024] [Revised: 08/03/2024] [Accepted: 08/08/2024] [Indexed: 08/13/2024]
Abstract
BACKGROUND The effects of sodium-glucose cotransporter 2 inhibitors (SGLT2i) on calcium phosphate homeostasis in patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) remain uncertain. METHODS A retrospective observational cohort study of patients with T2DM at CKD stage G3b-5ND who received SGLT2i as compared to control from 1 January 2015 through 31 December 2021 was recruited. Propensity score assignment at 1:3 ratio by logistic regression was done. All patients were followed for 12 months. Outcomes were changes in phosphate level. RESULTS We analyzed 1,450 SGLT2i users and 4,350 control subjects. At the 12th month, SGLT2i users had a slower increase in phosphate levels (absolute change: -0.01 ± 0.28 vs + 0.14 ± 0.34 mmol/L; percentage change: -0.74 % ± 25.56 vs + 10.88 ± 28.15 %, P for both < 0.001). The proportion of patients with high phosphate was lower with SGLT2i (8.2 % vs 24.6 % increase). In the generalized estimating equation, SGLT2i was linked to a longitudinal reduction in phosphate (B -0.039, P<0.001). CONCLUSIONS SGLT2i can effectively slow down the progression of phosphate retention in advanced CKD with T2DM.
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Affiliation(s)
- Gordon Chun Kau Chan
- Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region
| | - Jack Kit Chung Ng
- Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region; Li Ka Shing Institute of Health Sciences (LiHS), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region
| | - Cheuk Chun Szeto
- Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region; Li Ka Shing Institute of Health Sciences (LiHS), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region
| | - Kai Ming Chow
- Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region.
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2
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Hill Gallant KM, Sprague SM, Rosenbaum DP, Spiegel DM, Kozuka K, Edelstein S, Chertow GM. Tenapanor: A Phosphate Absorption Inhibitor for the Management of Hyperphosphatemia in Patients With Kidney Failure. J Ren Nutr 2024:S1051-2276(24)00156-0. [PMID: 38992521 DOI: 10.1053/j.jrn.2024.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 07/01/2024] [Indexed: 07/13/2024] Open
Abstract
Because of increased risks of cardiovascular disease and death, patients with hyperphosphatemia receiving maintenance dialysis are advised to limit phosphorus consumption and are prescribed phosphate binders in an effort to better control serum phosphate concentrations. Because of large pill size, pill burden, and tolerability issues, phosphate binder adherence is relatively poor. On ingestion, phosphate is absorbed from the intestine via transcellular or paracellular transport. Data show that inhibiting sodium-hydrogen exchanger 3 modulates paracellular phosphate absorption (the predominant pathway in humans). Tenapanor is a first-in-class, minimally absorbed, phosphate absorption inhibitor that selectively inhibits sodium-hydrogen exchanger 3, with a mechanism distinct from, and complementary to, that of phosphate binders. In phase 3 and postregistrational studies, tenapanor conferred statistically significant and clinically meaningful reductions in serum phosphate in patients receiving maintenance dialysis with hyperphosphatemia. Here, we review the available preclinical and clinical data on the effects of tenapanor on controlling intestinal phosphate absorption.
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Affiliation(s)
- Kathleen M Hill Gallant
- Associate Professor, Department of Food Science and Nutrition, University of Minnesota, Saint Paul, Minnesota.
| | - Stuart M Sprague
- Clinical Professor of Medicine, Endeavor Health, University of Chicago, Evanston, Illinois
| | | | - David M Spiegel
- Vice President, Nephrology, Ardelyx, Inc., Waltham, Massachusetts
| | - Kenji Kozuka
- Director, Preclinical Research and Nonclinical Development, Ardelyx, Inc., Fremont, California
| | - Susan Edelstein
- Senior Vice President, Clinical Research, Ardelyx, Inc., Waltham, Massachusetts
| | - Glenn M Chertow
- Professor of Medicine - Nephrology, Departments of Medicine and Epidemiology and Population Health, Stanford University, Palo Alto, California
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3
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Soeda K, Komaba H. Navigating How to Initiate Tenapanor Therapy in the Real World. KIDNEY360 2024; 5:938-940. [PMID: 39052472 PMCID: PMC11296554 DOI: 10.34067/kid.0000000000000488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Affiliation(s)
- Keisuke Soeda
- Division of Nephrology, Endocrinology and Metabolism, Tokai University School of Medicine, Isehara, Japan
| | - Hirotaka Komaba
- Division of Nephrology, Endocrinology and Metabolism, Tokai University School of Medicine, Isehara, Japan
- The Institute of Medical Sciences, Tokai University, Isehara, Japan
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4
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Shen Y. Pathogenesis and Mechanism of Uremic Vascular Calcification. Cureus 2024; 16:e64771. [PMID: 39026575 PMCID: PMC11255132 DOI: 10.7759/cureus.64771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2024] [Indexed: 07/20/2024] Open
Abstract
This review elucidates the modeling and mechanistic studies of vascular calcification in chronic kidney disease - mineral and bone disorder. In patients with chronic kidney disease, metabolic abnormalities in uremic toxins, including phosphate and indole sulfate, are closely associated with vascular calcification. Vitamin K, vascular circadian clock, and autophagy are also key factors involved in vascular calcification. Furthermore, communication between endothelial cells and smooth muscle cells also plays a pivotal role in the regulation of this process. Together, these factors accelerate vascular calcification progression and increase the risk of cardiovascular events. Therefore, timely intervention for vascular calcification is essential for patients with chronic kidney disease.
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Affiliation(s)
- Yingjing Shen
- Nephrology, Shanghai Tianyou Hospital, School of Medicine, Tongji University, Shanghai, CHN
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5
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Lacy BE, Rosenbaum D, Edelstein S, Kozuka K, Williams LA, Kunkel DC. Intestinal Permeability, Irritable Bowel Syndrome with Constipation, and the Role of Sodium-Hydrogen Exchanger Isoform 3 (NHE3). Clin Exp Gastroenterol 2024; 17:173-183. [PMID: 38860153 PMCID: PMC11164200 DOI: 10.2147/ceg.s455101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 05/19/2024] [Indexed: 06/12/2024] Open
Abstract
Increased intestinal permeability has been identified as one of the many pathophysiological factors associated with the development of irritable bowel syndrome (IBS), a common disorder of gut-brain interaction. The layer of epithelial cells that lines the intestine is permeable to a limited degree, and the amount of paracellular permeability is tightly controlled to enable the absorption of ions, nutrients, and water from the lumen. Increased intestinal permeability to macromolecules can be triggered by a variety of insults, including infections, toxins from food poisoning, or allergens, which in turn cause an inflammatory response and are associated with abdominal pain in patients with IBS. This review article discusses increased intestinal permeability in IBS, focusing on IBS with constipation (IBS-C) through the lens of a patient case with a reported prior diagnosis of "leaky gut syndrome" upon initial contact with a gastrointestinal specialist. We review advantages and disadvantages of several methods of measuring intestinal permeability in patients and discuss when measuring intestinal permeability is appropriate in the therapeutic journey of patients with IBS-C. Furthermore, we discuss a possible mechanism of restoring the intestinal barrier to its healthy state through altering intracellular pH by inhibiting sodium-hydrogen exchanger isoform 3 (NHE3). Tenapanor is a minimally absorbed, small-molecule inhibitor of NHE3 that has been approved by the US Food and Drug Administration for the treatment of IBS-C in adults. Preclinical studies showed that tenapanor may restore the intestinal barrier in IBS-C by affecting the conformation of tight junction proteins via NHE3 inhibition to block the paracellular transport of macromolecules from the intestinal lumen. Testing for increased permeability in patients with IBS-C who experience abdominal pain may help inform the choice of therapeutics and alter patients' misconceptions about "leaky gut syndrome".
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Affiliation(s)
- Brian E Lacy
- Division of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, FL, USA
| | | | | | | | | | - David C Kunkel
- Division of Gastroenterology, University of California San Diego, La Jolla, CA, USA
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6
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Guo L, Ji Y, Sun T, Liu Y, Jiang C, Wang G, Xing H, Yang B, Xu A, Xian X, Yang H. Management of Chronic Heart Failure in Dialysis Patients: A Challenging but Rewarding Path. Rev Cardiovasc Med 2024; 25:232. [PMID: 39076321 PMCID: PMC11270084 DOI: 10.31083/j.rcm2506232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 01/15/2024] [Accepted: 03/04/2024] [Indexed: 07/31/2024] Open
Abstract
Chronic heart failure (CHF) is a common complication and cause of death in dialysis patients. Although several clinical guidelines and expert consensus on heart failure (HF) in the general population have been issued in China and abroad, due to abnormal renal function or even no residual renal function (RRF) in dialysis patients, the high number of chronic complications, as well as the specificity, variability, and limitations of hemodialysis (HD) and peritoneal dialysis (PD) treatments, there are significant differences between dialysis patients and the general population in terms of the treatment and management of HF. The current studies are not relevant to all dialysis-combined HF populations, and there is an urgent need for high-quality studies on managing HF in dialysis patients to guide and standardize treatment. After reviewing the existing guidelines and literature, we focused on the staging and diagnosis of HF, management of risk factors, pharmacotherapy, and dialysis treatment in patients on dialysis. Based on evidence-based medicine and clinical trial data, this report reflects new perspectives and future trends in the diagnosis and treatment of HF in dialysis patients, which will further enhance the clinicians' understanding of HF in dialysis patients.
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Affiliation(s)
- Luxuan Guo
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300193 Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, 300193 Tianjin, China
- Tianjin University of Traditional Chinese Medicine, 301617 Tianjin, China
| | - Yue Ji
- Dongzhimen Hospital, Beijing University of Traditional Chinese Medicine, Institute of Nephrology & Beijing Key Laboratory, 100700 Beijing, China
| | - Tianhao Sun
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300193 Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, 300193 Tianjin, China
- Tianjin University of Traditional Chinese Medicine, 301617 Tianjin, China
| | - Yang Liu
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300193 Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, 300193 Tianjin, China
- Tianjin University of Traditional Chinese Medicine, 301617 Tianjin, China
| | - Chen Jiang
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300193 Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, 300193 Tianjin, China
- Tianjin University of Traditional Chinese Medicine, 301617 Tianjin, China
| | - Guanran Wang
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300193 Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, 300193 Tianjin, China
- Tianjin University of Traditional Chinese Medicine, 301617 Tianjin, China
| | - Haitao Xing
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300193 Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, 300193 Tianjin, China
- Tianjin University of Traditional Chinese Medicine, 301617 Tianjin, China
| | - Bo Yang
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300193 Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, 300193 Tianjin, China
- Tianjin University of Traditional Chinese Medicine, 301617 Tianjin, China
| | - Ao Xu
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300193 Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, 300193 Tianjin, China
- Tianjin University of Traditional Chinese Medicine, 301617 Tianjin, China
| | - Xian Xian
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300193 Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, 300193 Tianjin, China
- Tianjin University of Traditional Chinese Medicine, 301617 Tianjin, China
| | - Hongtao Yang
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300193 Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, 300193 Tianjin, China
- Tianjin University of Traditional Chinese Medicine, 301617 Tianjin, China
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Cernaro V, Longhitano E, Casuscelli C, Peritore L, Santoro D. Hyperphosphatemia in Chronic Kidney Disease: The Search for New Treatment Paradigms and the Role of Tenapanor. Int J Nephrol Renovasc Dis 2024; 17:151-161. [PMID: 38831770 PMCID: PMC11144652 DOI: 10.2147/ijnrd.s385826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 05/14/2024] [Indexed: 06/05/2024] Open
Abstract
Hyperphosphataemia represents a significant challenge in the management of chronic kidney disease, exerting a pronounced influence on the pathogenesis of cardiovascular complications and mineral bone disorders. Traditional approaches to address hyperphosphataemia involve implementing dietary phosphate restrictions, administering phosphate binders, and, in cases of end-stage renal disease, resorting to dialysis. Unfortunately, these interventions frequently prove inadequate in maintaining phosphate levels within recommended ranges. Additionally, commonly employed pharmacological agents are not immune to eliciting adverse events, thereby limiting their prescription and therapeutic adherence. There is a growing focus on exploring novel therapeutic strategies in this context. The current discussion centres on tenapanor, a pharmacological agent predominantly acting as a selective inhibitor of sodium/hydrogen exchanger isoform 3 (NHE3). Its mechanism of action involves modulating tight junctions, resulting in reduced sodium absorption and intestinal paracellular permeability to phosphate. Furthermore, tenapanor downregulates sodium-dependent phosphate 2b transport protein (NaPi2b) expression, thereby impeding active transcellular phosphate transport. Clinical trials have elucidated the efficacy and safety profile of tenapanor. This evidence hints at a potential paradigm shift in the management of hyperphosphataemia. However, the burgeoning optimism surrounding tenapanor warrants tempered enthusiasm, as further research remains indispensable. The imperative lies in meticulously delineating its efficacy and safety contours within the crucible of clinical practice. In this review, we synthesize the intricate interplay between hyperphosphataemia and Chronic Kidney Disease-Mineral Bone Disorder, and we discuss the existing pharmacological interventions for hyperphosphataemia and explore emerging treatment paradigms that offer novel perspectives in managing elevated phosphate levels in CKD patients.
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Affiliation(s)
- Valeria Cernaro
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Elisa Longhitano
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Chiara Casuscelli
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Luigi Peritore
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Domenico Santoro
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
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8
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Lembo AJ, Chey WD, Harris LA, Frazier R, Brenner DM, Chang L, Lacy BE, Edelstein S, Yang Y, Zhao S, Rosenbaum DP. Abdominal Symptom Improvement During Clinical Trials of Tenapanor in Patients With Irritable Bowel Syndrome With Constipation: A Post Hoc Analysis. Am J Gastroenterol 2024; 119:937-945. [PMID: 38294158 PMCID: PMC11062617 DOI: 10.14309/ajg.0000000000002685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 12/20/2023] [Indexed: 02/01/2024]
Abstract
INTRODUCTION This post hoc analysis evaluated the efficacy of tenapanor on abdominal symptoms in patients with irritable bowel syndrome with constipation. Abdominal symptoms assessed included pain, discomfort, bloating, cramping, and fullness. METHODS The abdominal symptom data were pooled from 3 randomized controlled trials (NCT01923428, T3MPO-1 [NCT02621892], and T3MPO-2 [NCT02686138]). Weekly scores were calculated for each abdominal symptom, and the Abdominal Score (AS) was derived as the average of weekly scores for abdominal pain, discomfort, and bloating. The overall change from baseline during the 12 weeks was assessed for each symptom weekly score and the AS. The AS 6/12-week and 9/12-week response rates (AS improvement of ≥2 points for ≥6/12- or ≥9/12-week) were also evaluated. The association of weekly AS response status (reduction of ≥30%) with weekly complete spontaneous bowel movement (CSBM) status (=0 and >0) was assessed. RESULTS Among 1,372 patients (684 tenapanor [50 mg twice a day] and 688 placebo), the least squares mean change from baseline in AS was -2.66 for tenapanor vs -2.09 for placebo ( P < 0.0001). The 6/12-week AS response rate was 44.4% for tenapanor vs 32.4% for placebo ( P < 0.0001), and for 9/12-week AS, 30.6% for tenapanor vs 20.5% for placebo ( P < 0.0001). A significant association between weekly CSBM status and weekly AS response status was observed each week ( P < 0.0001), with a greater proportion achieving an AS reduction in patients with >0 CSBMs in a week. DISCUSSION Tenapanor significantly reduced abdominal symptoms in patients with irritable bowel syndrome with constipation, particularly pain, discomfort, and bloating measured by AS, compared with placebo.
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Affiliation(s)
- Anthony J. Lembo
- Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - William D. Chey
- Division of Gastroenterology, Department of Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Lucinda A. Harris
- Division of Gastroenterology & Hepatology, Mayo Clinic, Scottsdale, Arizona, USA
| | - Rosita Frazier
- Division of Gastroenterology & Hepatology, Mayo Clinic, Scottsdale, Arizona, USA
| | - Darren M. Brenner
- Division of Gastroenterology and Hepatology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Lin Chang
- Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, California
| | - Brian E. Lacy
- Division of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, Florida, USA
| | | | - Yang Yang
- Ardelyx, Waltham, Massachusetts, USA
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King AJ, Chang L, Li Q, Liu L, Zhu Y, Pasricha PJ, Wang J, Siegel M, Caldwell JS, Edelstein S, Rosenbaum DP, Kozuka K. NHE3 inhibitor tenapanor maintains intestinal barrier function, decreases visceral hypersensitivity, and attenuates TRPV1 signaling in colonic sensory neurons. Am J Physiol Gastrointest Liver Physiol 2024; 326:G543-G554. [PMID: 38252683 DOI: 10.1152/ajpgi.00233.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/04/2024] [Accepted: 01/17/2024] [Indexed: 01/24/2024]
Abstract
The pathogenesis of irritable bowel syndrome (IBS) is multifactorial, characterized in part by increased intestinal permeability, and visceral hypersensitivity. Increased permeability is associated with IBS severity and abdominal pain. Tenapanor is FDA-approved for the treatment of IBS with constipation (IBS-C) and has demonstrated improvements in bowel motility and a reduction in IBS-related pain; however, the mechanism by which tenapanor mediates these functions remains unclear. Here, the effects of tenapanor on colonic pain signaling and intestinal permeability were assessed through behavioral, electrophysiological, and cell culture experiments. Intestinal motility studies in rats and humans demonstrated that tenapanor increased luminal sodium and water retention and gastrointestinal transit versus placebo. A significantly reduced visceral motor reflex (VMR) to colonic distension was observed with tenapanor treatment versus vehicle in two rat models of visceral hypersensitivity (neonatal acetic acid sensitization and partial restraint stress; both P < 0.05), returning VMR responses to that of nonsensitized controls. Whole cell voltage patch-clamp recordings of retrogradely labeled colonic dorsal root ganglia (DRG) neurons from sensitized rats found that tenapanor significantly reduced DRG neuron hyperexcitability to capsaicin versus vehicle (P < 0.05), an effect not mediated by epithelial cell secretions. Tenapanor also attenuated increases in intestinal permeability in human colon monolayer cultures caused by incubation with proinflammatory cytokines (P < 0.001) or fecal supernatants from patients with IBS-C (P < 0.005). These results support a model in which tenapanor reduces IBS-related pain by strengthening the intestinal barrier, thereby decreasing permeability to macromolecules and antigens and reducing DRG-mediated pain signaling.NEW & NOTEWORTHY A series of nonclinical experiments support the theory that tenapanor inhibits IBS-C-related pain by strengthening the intestinal barrier. Tenapanor treatment reduced visceral motor responses to nonsensitized levels in two rat models of hypersensitivity and reduced responses to capsaicin in sensitized colonic nociceptive dorsal root ganglia neurons. Intestinal permeability experiments in human colon monolayer cultures found that tenapanor attenuates increases in permeability induced by either inflammatory cytokines or fecal supernatants from patients with IBS-C.
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Affiliation(s)
- Andrew J King
- Ardelyx, Inc., Waltham, Massachusetts, United States
| | - Lin Chang
- Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States
| | - Qian Li
- Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Liansheng Liu
- Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Yaohui Zhu
- Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Pankaj J Pasricha
- Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Ji Wang
- Ardelyx, Inc., Waltham, Massachusetts, United States
| | | | | | | | | | - Kenji Kozuka
- Ardelyx, Inc., Waltham, Massachusetts, United States
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10
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Sprague SM, Weiner DE, Tietjen DP, Pergola PE, Fishbane S, Block GA, Silva AL, Fadem SZ, Lynn RI, Fadda G, Pagliaro L, Zhao S, Edelstein S, Spiegel DM, Rosenbaum DP. Tenapanor as Therapy for Hyperphosphatemia in Maintenance Dialysis Patients: Results from the OPTIMIZE Study. KIDNEY360 2024; 5:732-742. [PMID: 38323855 PMCID: PMC11146652 DOI: 10.34067/kid.0000000000000387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 02/01/2024] [Indexed: 02/08/2024]
Abstract
Key Points Tenapanor, a first-in-class local inhibitor of sodium/hydrogen exchanger isoform 3, acts as a phosphate absorption inhibitor by decreasing paracellular phosphate absorption. Tenapanor alone or with phosphate binders achieved P ≤ 5.5 mg/dl over 10 weeks in 34%–38% of patients taking phosphate binders at baseline. Tenapanor can help adults with CKD on maintenance dialysis achieve normal serum phosphate concentrations. Background OPTIMIZE was a randomized, open-label study evaluating different tenapanor initiation methods. OPTIMIZE evaluated tenapanor alone and in combination with phosphate binders (PBs) to achieve target serum phosphate (P) ≤5.5 mg/dl. Methods Patients with inadequately controlled P receiving maintenance dialysis from 42 US locations who were taking PBs with baseline P > 5.5 mg/dl and ≤ 10.0 mg/dl, or were PB-naive with baseline P > 4.5 mg/dl and ≤ 10.0 mg/dl, were included in OPTIMIZE. Participants taking PBs at baseline were randomized to switch from PBs to tenapanor (Straight Switch ; n =151) or reduce PB dosage by ≥50% and add tenapanor (Binder Reduction ; n =152); PB-naive patients started tenapanor alone (Binder-Naive ; n =30). Participants received tenapanor 30 mg twice a day for 10 weeks (part A), followed by an elective, 16-week open-label extension (part B). Outcomes included changes from baseline in P, intact fibroblast growth factor 23, parathyroid hormone, serum calcium, and medication burden; patient-reported outcomes; and safety. Results By part A end point, 34.4% (Straight Switch ), 38.2% (Binder Reduction ), and 63.3% (Binder-Naive ) of patients achieved P ≤ 5.5 mg/dl. Mean P reduction and median pill burden reduction from baseline to part A end point were 0.91±1.7 mg/dl and 4 pills/d for the Straight Switch and 0.99±1.8 mg/dl and 1 pill/d for the Binder Reduction group. The mean P reduction for Binder-Naive patients was 0.87±1.5 mg/dl. Among Straight Switch and Binder Reduction patients who completed patient experience questionnaires, 205 of 243 (84.4%) reported an improved phosphate management routine. Diarrhea was the most common adverse event (133 of 333 [39.9%]). Conclusions Tenapanor as monotherapy or in combination with PBs effectively lowered P toward the target range in patients who were PB-naive or who were not at goal despite PB use. Clinical Trial registration number NCT04549597 .
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Affiliation(s)
- Stuart M. Sprague
- NorthShore University Health System, Evanston, Illinois
- University of Chicago Pritzker School of Medicine, Chicago, Illinois
| | | | | | | | - Steven Fishbane
- Zucker School of Medicine at Hofstra & Northwell Health, Great Neck, New York
| | | | | | - Stephen Z. Fadem
- Kidney Associates, PLLC and Baylor College of Medicine, Houston, Texas
| | | | - George Fadda
- Balboa Nephrology Medical Group, La Mesa, California
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11
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Walker V. The Intricacies of Renal Phosphate Reabsorption-An Overview. Int J Mol Sci 2024; 25:4684. [PMID: 38731904 PMCID: PMC11083860 DOI: 10.3390/ijms25094684] [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: 03/24/2024] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 05/13/2024] Open
Abstract
To maintain an optimal body content of phosphorus throughout postnatal life, variable phosphate absorption from food must be finely matched with urinary excretion. This amazing feat is accomplished through synchronised phosphate transport by myriads of ciliated cells lining the renal proximal tubules. These respond in real time to changes in phosphate and composition of the renal filtrate and to hormonal instructions. How they do this has stimulated decades of research. New analytical techniques, coupled with incredible advances in computer technology, have opened new avenues for investigation at a sub-cellular level. There has been a surge of research into different aspects of the process. These have verified long-held beliefs and are also dramatically extending our vision of the intense, integrated, intracellular activity which mediates phosphate absorption. Already, some have indicated new approaches for pharmacological intervention to regulate phosphate in common conditions, including chronic renal failure and osteoporosis, as well as rare inherited biochemical disorders. It is a rapidly evolving field. The aim here is to provide an overview of our current knowledge, to show where it is leading, and where there are uncertainties. Hopefully, this will raise questions and stimulate new ideas for further research.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton S016 6YD, UK
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12
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Singh P, Sayuk GS, Rosenbaum DP, Edelstein S, Kozuka K, Chang L. An Overview of the Effects of Tenapanor on Visceral Hypersensitivity in the Treatment of Irritable Bowel Syndrome with Constipation. Clin Exp Gastroenterol 2024; 17:87-96. [PMID: 38617992 PMCID: PMC11016248 DOI: 10.2147/ceg.s454526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 03/22/2024] [Indexed: 04/16/2024] Open
Abstract
Background Patients with irritable bowel syndrome with constipation (IBS-C) experience persistent abdominal pain, a common symptom leading to greater healthcare utilization and reports of treatment non-response. Clinically significant improvements in abdominal pain were observed in clinical trials of tenapanor, a first-in-class inhibitor of sodium/hydrogen exchanger isoform 3 (NHE3), for the treatment of IBS-C in adults. Aim This narrative review reports the current knowledge about visceral hypersensitivity as a mechanism for abdominal pain in patients with IBS-C and explores the published evidence for hypothesized mechanisms by which tenapanor may reduce visceral hypersensitivity leading to the observed clinical response of decreased abdominal pain. Findings Abdominal pain is experienced through activation and signaling of nociceptive dorsal root ganglia that innervate the gut. These sensory afferent neurons may become hypersensitized through signaling of transient receptor potential cation channel subfamily V member 1 (TRPV1), resulting in reduced action potential thresholds. TRPV1 signaling is also a key component of the proinflammatory cascade involving mast cell responses to macromolecule exposure following permeation through the intestinal epithelium. Indirect evidence of this pathway is supported by observations of higher pain in association with increased intestinal permeability in patients with IBS. Tenapanor reduces intestinal sodium absorption, leading to increased water retention in the intestinal lumen, thereby improving gastrointestinal motility. In animal models of visceral hypersensitivity, tenapanor normalized visceromotor responses and normalized TRPV1-mediated nociceptive signaling. Conclusion By improving gastrointestinal motility, decreasing intestinal permeability and inflammation, and normalizing nociception through decreased TRPV1 signaling, tenapanor may reduce visceral hypersensitivity, leading to less abdominal pain in patients with IBS-C. Therapies that have demonstrated effects on visceral hypersensitivity may be the future direction for meaningful abdominal pain relief for patients with IBS-C.
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Affiliation(s)
- Prashant Singh
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Gregory S Sayuk
- Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
| | | | | | | | - Lin Chang
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
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Turner ME, Beck L, Hill Gallant KM, Chen Y, Moe OW, Kuro-o M, Moe S, Aikawa E. Phosphate in Cardiovascular Disease: From New Insights Into Molecular Mechanisms to Clinical Implications. Arterioscler Thromb Vasc Biol 2024; 44:584-602. [PMID: 38205639 PMCID: PMC10922848 DOI: 10.1161/atvbaha.123.319198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Hyperphosphatemia is a common feature in patients with impaired kidney function and is associated with increased risk of cardiovascular disease. This phenomenon extends to the general population, whereby elevations of serum phosphate within the normal range increase risk; however, the mechanism by which this occurs is multifaceted, and many aspects are poorly understood. Less than 1% of total body phosphate is found in the circulation and extracellular space, and its regulation involves multiple organ cross talk and hormones to coordinate absorption from the small intestine and excretion by the kidneys. For phosphate to be regulated, it must be sensed. While mostly enigmatic, various phosphate sensors have been elucidated in recent years. Phosphate in the circulation can be buffered, either through regulated exchange between extracellular and cellular spaces or through chelation by circulating proteins (ie, fetuin-A) to form calciprotein particles, which in themselves serve a function for bulk mineral transport and signaling. Either through direct signaling or through mediators like hormones, calciprotein particles, or calcifying extracellular vesicles, phosphate can induce various cardiovascular disease pathologies: most notably, ectopic cardiovascular calcification but also left ventricular hypertrophy, as well as bone and kidney diseases, which then propagate phosphate dysregulation further. Therapies targeting phosphate have mostly focused on intestinal binding, of which appreciation and understanding of paracellular transport has greatly advanced the field. However, pharmacotherapies that target cardiovascular consequences of phosphate directly, such as vascular calcification, are still an area of great unmet medical need.
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Affiliation(s)
- Mandy E. Turner
- Division of Cardiovascular Medicine, Department of Medicine, Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Laurent Beck
- Nantes Université, CNRS, Inserm, l’institut du thorax, F-44000 Nantes, France
| | - Kathleen M Hill Gallant
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota, USA
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Yabing Chen
- Department of Pathology, University of Alabama at Birmingham
- Research Department, Veterans Affairs Birmingham Medical Center, Birmingham, AL, USA
| | - Orson W Moe
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Makoto Kuro-o
- Division of Anti-aging Medicine, Center for Molecular Medicine, Jichi Medical University 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Sharon Moe
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Elena Aikawa
- Division of Cardiovascular Medicine, Department of Medicine, Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
- Division of Cardiovascular Medicine, Department of Medicine, Center for Excellence in Vascular Biology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
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Shang G, Niu X, Tong Q, Zhao Y, Yin J, Zhou X, Xu J, Cao Y, Cheng F, Bao B, Li Z, Yao W. Integrated metabolomic and lipidomic analysis revealed the protective mechanisms of Erzhi Wan on senescent NRK cells through BRL cells. JOURNAL OF ETHNOPHARMACOLOGY 2024; 320:117482. [PMID: 38000520 DOI: 10.1016/j.jep.2023.117482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 11/08/2023] [Accepted: 11/17/2023] [Indexed: 11/26/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Erzhi Wan (EZW), as a prescription of traditional Chinese medicine, has been used for tonifying the liver and kidney. Although past studies have shown that EZW has potential anti-aging effect, the mechanisms associated with cellular metabolomics and lipidomics are not fully understood. AIM OF THE STUDY This study aimed to evaluate the anti-aging effect of EZW and investigate the mechanisms associated with cellular metabolomics and lipidomics. MATERIALS AND METHODS EZW solution at dosage of 3.6 g/kg in Sprague-Dawley rats was orally administered twice a day for 7 days and serum containing EZW was then collected. NRK cell senescence model induced by D-galactose was established in vitro, and non-contact co-culture cell assay was performed between senescent NRK cells and BRL cells intervened by serum containing EZW. The anti-aging effect of EZW on NRK cells was evaluated by metabolites identification, differential metabolites screening and metabolic pathways analysis through cellular metabolomics with GC-MS and lipidomics with UHPLC-Q-Exactive Orbitrap/MS. RESULTS Serum containing EZW indicated a protective effect through intervening BRL cells in non-contact co-culture system with D-gal-induced senescent NRK cells. For metabolic profiles, 71 endogenous metabolites were identified, among which 24 significantly differential metabolites were screened as metabolomics potential biomarkers. For lipidic profiles, 64 lipid components were identified in NRK cell samples under positive ion mode, among which 24 potential biomarkers of lipids were screened, mainly including PC and PE. 127 lipid components were identified in NRK cell samples under negative ion mode, among which 59 potential biomarkers of lipids were screened, including FA, PC, PE, PI and PS. Metabolic pathway analysis demonstrated that the identified differential metabolites found mainly involved in amino acids metabolism, energy metabolism and phospholipid biosynthesis pathways. CONCLUSION Serum containing EZW exhibited protective effect on D-gal-induced senescent NRK cells through intervening BRL cells by mainly regulating amino acids metabolism, energy metabolism and phospholipid biosynthesis pathways to possess its anti-aging function, providing a theoretical basis for clinical treatment of EZW.
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Affiliation(s)
- Guanxiong Shang
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Xuan Niu
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Qingheng Tong
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Yan Zhao
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Jiu Yin
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Xiaoqi Zhou
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Jia Xu
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Yudan Cao
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Fangfang Cheng
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Beihua Bao
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Zhipeng Li
- Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research & the Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, 210009, China.
| | - Weifeng Yao
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
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15
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Salcedo-Betancourt JD, Moe OW. The Effects of Acid on Calcium and Phosphate Metabolism. Int J Mol Sci 2024; 25:2081. [PMID: 38396761 PMCID: PMC10889523 DOI: 10.3390/ijms25042081] [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: 01/03/2024] [Revised: 02/04/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
A variety of changes in mineral metabolism aiming to restore acid-base balance occur in acid loading and metabolic acidosis. Phosphate plays a key role in defense against metabolic acidosis, both as an intracellular and extracellular buffer, as well as in the renal excretion of excess acid in the form of urinary titratable acid. The skeleton acts as an extracellular buffer in states of metabolic acidosis, as the bone matrix demineralizes, leading to bone apatite dissolution and the release of phosphate, calcium, carbonate, and citrate into the circulation. The renal handling of calcium, phosphate and citrate is also affected, with resultant hypercalciuria, hyperphosphaturia and hypocitraturia.
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Affiliation(s)
- Juan D. Salcedo-Betancourt
- Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Orson W. Moe
- Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Gan L, Xing L, Xu Y, Zhou L, Jiang H, Sun X, Guan T, Luo P, Wang J, Sun F, Guo Z, Guo M, Gao J, Wei G, Zhong W, Zhou Y, Zuo L. Tenapanor in Chinese ESRD patients with hyperphosphatemia on haemodialysis: a randomised, phase 3 trial. Clin Kidney J 2024; 17:sfad216. [PMID: 38186905 PMCID: PMC10768776 DOI: 10.1093/ckj/sfad216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Indexed: 01/09/2024] Open
Abstract
Background The efficacy and safety of tenapanor has not been confirmed in Chinese end-stage renal disease (ESRD) patients with hyperphosphatemia on haemodialysis (HD). Methods This was a randomised, double blind, phase 3 trial conducted at 26 dialysis facilities in China (https://www.chictr.org.cn/index.aspx; CTR20202588). After a 3-week washout, adults with ESRD on HD with hyperphosphatemia were randomised (1:1) using an interactive web response system to oral tenapanor 30 mg twice a day or placebo for 4 weeks. The primary endpoint was the change in mean serum phosphorous level from baseline to the endpoint visit (day 29 or last serum phosphorus measurement). Efficacy was analysed in the intention-to-treat population. Safety was assessed in all patients who received at least one dose of the study drug. Results Between 5 March 2021 and 8 June 2022, 77 patients received tenapanor and 73 received placebo. Tenapanor treatment (n = 75) resulted in a significantly greater least squares (LS) mean reduction in serum phosphate at the endpoint visit versus placebo (n = 72): LS mean difference -1.17 mg/dl (95% CI -1.694 to -0.654, P < .001). More patients receiving tenapanor achieved a serum phosphorous level <5.5 mg/dl at the endpoint visit (44.6% versus 10.1%). The most common treatment-related adverse event was diarrhoea [tenapanor 28.6% (22/77), placebo 2.7% (2/73)], which was mostly mild and led to treatment discontinuation in two patients receiving tenapanor. Conclusions Tenapanor significantly reduced the serum phosphorous level versus placebo in Chinese ESRD patients on HD and was generally well tolerated.
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Affiliation(s)
- Liangying Gan
- Department of Nephrology, Peking University People's Hospital, Beijing, China
| | - Li Xing
- Hemodialysis Room, People's Hospital of Zhengzhou, Zhengzhou, China
| | - Yan Xu
- Department of Nephrology, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Linghui Zhou
- Department of Nephrology, First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Hong Jiang
- Division of Nephrology, Department of Internal Medicine, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
| | - Xiuli Sun
- Department of Nephrology, Baotou Central Hospital, Baotou, China
| | - Tianjun Guan
- Department of Nephrology, Zhongshan Hospital Xiamen University, Xiamen, China
| | - Ping Luo
- Department of Nephrology, Second Hospital of Jilin University, Changchun, China
| | - Junxia Wang
- Blood Purifying Center, First Affiliated Hospital of Henan University of Science and Technology, Luoyang, China
| | - Fuyun Sun
- Department of Nephrology, Cangzhou Center Hospital, Cangzhou, China
| | - Zhiyong Guo
- Department of Nephrology, Shanghai Changhai Hospital, Shanghai, China
| | - Minghao Guo
- Department of Nephrology, First Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Ju Gao
- Panjin Liaohe Oilfield Baoshihua Hospital, Panjin, China
| | - Gang Wei
- R&D Center, Fosun Pharma, Shanghai, China
| | - Wen Zhong
- R&D Center, Fosun Pharma, Shanghai, China
| | | | - Li Zuo
- Department of Nephrology, Peking University People's Hospital, Beijing, China
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17
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Currò D, Ianiro G, Gasbarrini A. A pharmacokinetic evaluation of tenapanor for the treatment of irritable bowel syndrome with constipation: an update of the literature. Expert Opin Drug Metab Toxicol 2023; 19:889-894. [PMID: 38108081 DOI: 10.1080/17425255.2023.2294937] [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: 08/04/2023] [Accepted: 12/11/2023] [Indexed: 12/19/2023]
Abstract
INTRODUCTION Tenapanor is the latest addition to the second-line pharmacotherapeutic options for the treatment of irritable bowel syndrome with constipation. It is a first-in-class inhibitor of type 3 sodium/hydrogen exchanger (NHE3), characterized by very low oral absorption. Its pharmacological properties are discussed here based on the latest literature. AREAS COVERED A general description of tenapanor is provided, highlighting those pharmacokinetic and pharmacodynamic characteristics of the drug which may be of major importance for tolerability and safety. This description is associated with a summary and analysis of currently available toxicological data. EXPERT OPINION Plasma concentrations of free tenapanor after oral administration are well below the half maximal inhibitory concentration for NHE3, so that systemic effects of the drug are minimal. Therefore, the action of tenapanor is limited to NHE3 located on the apical membrane of enterocytes. The consequent reduction in intestinal sodium absorption increases the intraluminal content by osmosis, which in turn enhances the propulsive activity of the colon. Diarrhea is the most frequent adverse effect of tenapanor. Increased fecal sodium and water excretion do not appear to expose patients to short- and long-term hydro-electrolyte imbalances.
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Affiliation(s)
- Diego Currò
- Pharmacology Section, Department of Health Care Surveillance and Bioethics, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Gianluca Ianiro
- Department of Translational Medicine and Surgery, Università Cattolica del Sacro Cuore, Rome, Italy
- Department of Medical and Surgical Sciences, UOC CEMAD Centro Malattie dell'Apparato Digerente, Medicina Interna e Gastroenterologia, Fondazione Policlinico Universitario Gemelli IRCCS, Rome, Italy
| | - Antonio Gasbarrini
- Department of Translational Medicine and Surgery, Università Cattolica del Sacro Cuore, Rome, Italy
- Department of Medical and Surgical Sciences, UOC CEMAD Centro Malattie dell'Apparato Digerente, Medicina Interna e Gastroenterologia, Fondazione Policlinico Universitario Gemelli IRCCS, Rome, Italy
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Koiwa F, Sato Y, Ohara M, Nakanishi K, Fukagawa M, Akizawa T. Long-term safety and decrease of pill burden by tenapanor therapy: a phase 3 open-label study in hemodialysis patients with hyperphosphatemia. Sci Rep 2023; 13:19100. [PMID: 37925471 PMCID: PMC10625594 DOI: 10.1038/s41598-023-45080-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 10/16/2023] [Indexed: 11/06/2023] Open
Abstract
Phosphate binders (PBs) generally have a high pill burden. Tenapanor selectively inhibits sodium/hydrogen exchanger isoform 3, reducing intestinal phosphate absorption. Tenapanor is a novel drug administered as a small tablet, twice daily. This multicenter, open-label, single-arm, phase 3 study aimed to evaluate the long-term safety of tenapanor and its efficacy in decreasing PB pill burden. Tenapanor 5 mg twice daily was administered to hemodialysis patients with serum phosphorus level 3.5-7.0 mg/dl at baseline; the dose could be increased up to 30 mg twice daily. Patients could also switch from PBs. The primary endpoint was safety during 52-week administration. The key secondary endpoint was a ≥ 30% reduction in the total pill number of daily PBs and tenapanor from baseline. Of 212 patients starting treatment, 154 completed the study. Diarrhea was the most frequent adverse event, occurring in 135 patients (63.7%); most events were classified as mild (74.8%). No clinically significant changes occurred other than serum phosphorus level. At Week 52/discontinuation, 158/204 patients (77.5%) achieved the key secondary endpoint. Complete switching from PBs to tenapanor was achieved in 50-76 patients (26.7%-41.5%), and 80 patients (51.9%) at Week 8-12 and Week 50, respectively. Serum phosphorus remained generally stable within the target range (3.5-6.0 mg/dl). These findings suggest the long-term safety and tolerability of tenapanor. Tenapanor could reduce or eliminate PB pill burden while controlling serum phosphorus levels.Trial registration: NCT04771780.
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Affiliation(s)
- Fumihiko Koiwa
- Division of Nephrology, Department of Internal Medicine, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-Ku, Yokohama, 227-8501, Japan.
| | - Yu Sato
- R&D Division, Kyowa Kirin Co., Ltd., Tokyo, Japan
| | - Meiko Ohara
- R&D Division, Kyowa Kirin Co., Ltd., Tokyo, Japan
| | | | - Masafumi Fukagawa
- Division of Nephrology, Endocrinology, and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa, Japan
| | - Tadao Akizawa
- Division of Nephrology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan
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Lembo AJ, Friedenberg KA, Fogel RP, Edelstein S, Zhao S, Yang Y, Rosenbaum DP, Chey WD. Long-term safety of tenapanor in patients with irritable bowel syndrome with constipation in the T3MPO-3 study. Neurogastroenterol Motil 2023; 35:e14658. [PMID: 37668173 DOI: 10.1111/nmo.14658] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 06/26/2023] [Accepted: 07/31/2023] [Indexed: 09/06/2023]
Abstract
BACKGROUND Tenapanor, a first-in-class, minimally systemic inhibitor of intestinal sodium/hydrogen exchanger isoform 3 (NHE3), is approved for the treatment of irritable bowel syndrome with constipation (IBS-C) in adults based on two randomized, placebo-controlled, phase III studies (T3MPO-1 [NCT02621892], T3MPO-2 [NCT02686138]). The open-label T3MPO-3 extension study (NCT02727751) enrolled patients who completed these studies to investigate long-term safety and tolerability of tenapanor. METHODS Patients who completed T3MPO-1 (16 weeks) or T3MPO-2 (26 weeks) were eligible for enrollment in T3MPO-3. Patients in T3MPO-3 received open-label tenapanor 50 mg twice a day for up to an additional 39 (T3MPO-1) or 26 (T3MPO-2) weeks. Treatment-emergent adverse events (TEAEs) were evaluated in the entire T3MPO-3 safety population and in patients who received a total of ≥52 weeks of tenapanor. KEY RESULTS A total of 312 patients were enrolled in T3MPO-3; 90 received ≥52 weeks of tenapanor. TEAEs were reported in 117 (37.5%) patients in the safety population and in 52 (57.8%) patients who received ≥52 weeks of tenapanor. Diarrhea was the most common TEAE, occurring in 10.6% of the safety population and in 11.1% of patients who received ≥52 weeks of tenapanor. Most cases were mild or moderate in severity, with only two severe cases reported in the safety population. No deaths occurred during the T3MPO-3 study. CONCLUSIONS Tenapanor was tolerable over ≥52 weeks of treatment and showed similar safety to that seen in shorter studies. Combined results of the T3MPO studies indicate that tenapanor is a valuable new treatment option for patients with IBS-C.
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Affiliation(s)
- Anthony J Lembo
- Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | | | - Ronald P Fogel
- Digestive Health Center of Michigan, Chesterfield, Michigan, USA
| | | | | | - Yang Yang
- Ardelyx, Inc., Waltham, Massachusetts, USA
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Silva AL, Chertow GM, Hernandez GT, Lynn RI, Tietjen DP, Rosenbaum DP, Yang Y, Edelstein S. Tenapanor Improves Long-Term Control of Hyperphosphatemia in Patients Receiving Maintenance Dialysis: the NORMALIZE Study. KIDNEY360 2023; 4:1580-1589. [PMID: 37853560 PMCID: PMC10695649 DOI: 10.34067/kid.0000000000000280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 10/11/2023] [Indexed: 10/20/2023]
Abstract
Key Points Tenapanor is a first-in-class, minimally systemic sodium–hydrogen exchanger 3 inhibitor with a mechanism of action distinct from phosphate binders. Tenapanor alone or with phosphate binders led to 35%–49% of patients achieving serum phosphate ≤4.5 mg/dl over an 18-month period versus 22% at baseline. Tenapanor alone or with phosphate binders may help adults with CKD on maintenance dialysis achieve normal serum phosphate concentrations. Background Most patients with ESKD and hyperphosphatemia have difficulty controlling serum phosphate (sP) concentrations despite maintenance dialysis, dietary restriction, and phosphate binder treatment. NORMALIZE evaluated the efficacy and safety of tenapanor 30 mg twice daily alone or in combination with phosphate binders to achieve sP within the adult population reference range (2.5–4.5 mg/dl). Methods Patients who completed the Phase 3 PHREEDOM study could enroll in NORMALIZE. Patients enrolled in NORMALIZE who had received tenapanor during the PHREEDOM study (n =111) added sevelamer carbonate if sP was >4.5 mg/dl. Patients who had received sevelamer carbonate during the PHREEDOM study (n =61) added tenapanor and decreased sevelamer carbonate if sP was ≤4.5 mg/dl, per protocol titration schedule. Patients were followed in NORMALIZE for up to 18 months. We assessed efficacy in the full analysis set, defined as patients who received ≥1 dose of study drug and had ≥1 post-treatment sP measurement (n =171). We assessed safety in all patients who received ≥1 dose of study drug (n =172). Results At the end point visit, 57 of 171 patients (33%) in the full analysis set achieved sP between 2.5 and 4.5 mg/dl. Eight of 23 patients (35%) who were on tenapanor alone at the end point visit achieved sP between 2.5 and 4.5 mg/dl. The mean reduction from PHREEDOM baseline to end of NORMALIZE in sP was 2.0 mg/dl. Serum intact fibroblast growth factor-23 was significantly reduced; serum intact parathyroid hormone was significantly reduced among patients with intact parathyroid hormone ≥300 pg/ml at PHREEDOM baseline. The most commonly reported treatment-emergent adverse event was diarrhea in 38 of 172 patients (22%), which led to tenapanor discontinuation in four patients (2%). Conclusions Tenapanor alone or in combination with phosphate binders helped adult patients on maintenance dialysis achieve normal sP concentrations. Safety was consistent with previous studies of tenapanor. Clinical trial registry name and registration number A Long-Term Study to Evaluate the Ability of Tenapanor Alone or in Combination With Sevelamer to Treat to Goal Serum Phosphorus in Patients With ESKD on Dialysis (NORMALIZE), NCT03988920 .
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Affiliation(s)
| | - Glenn M. Chertow
- Departments of Medicine and Epidemiology and Population Health, Stanford University School of Medicine, Stanford, California
| | | | | | | | | | - Yang Yang
- Ardelyx, Inc., Waltham, Massachusetts
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Biruete A, Hill Gallant KM, Lloyd L, Meade A, Moe SM, St-Jules DE, Kistler BM. 'Phos'tering a Clear Message: The Evolution of Dietary Phosphorus Management in Chronic Kidney Disease. J Ren Nutr 2023; 33:S13-S20. [PMID: 37343779 PMCID: PMC10728341 DOI: 10.1053/j.jrn.2023.05.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 04/21/2023] [Accepted: 05/04/2023] [Indexed: 06/23/2023] Open
Abstract
Phosphorus is a vital nutrient, but disturbances in phosphorus homeostasis are central to chronic kidney disease-mineral and bone disorder. To minimize disturbances, traditional dietary guidance focused on a numerical phosphorus target leading to the exclusion of many healthy foods and implementation challenges. Contemporary phosphorus guidance focuses on dietary source, avoiding additives, and emphasizing low-phosphorus bioaccessibility foods, leading to a more liberal approach. Additional work is needed to demonstrate the efficacy of these contemporary approaches and understand the influence of specific foods, processing, and cooking methods. Unfortunately, patient education using traditional and contemporary strategies may give mixed messages, particularly related to plant-based foods. Thus, greater clarity on the effects of specific foods and dietary patterns may improve phosphorus education. This review aims to discuss the evolution of dietary phosphorus management while highlighting areas for future research that can help move the field toward stronger evidence-based guidance to prevent and treat hyperphosphatemia.
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Affiliation(s)
- Annabel Biruete
- Department of Nutrition and Dietetics, Indiana University-Purdue University Indianapolis, Indianapolis; Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis; Department of Nutrition Science, Purdue University, West Lafayette, Indiana
| | - Kathleen M Hill Gallant
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis; Department of Food Science and Nutrition, University of Minnesota, St. Paul
| | - Lyn Lloyd
- Nutrition and Dietetics, Auckland City Hospital, Auckland, New Zealand
| | - Anthony Meade
- Central Northern Adelaide Renal and Transplantation Service, Royal Adelaide Hospital, Adelaide, Australia
| | - Sharon M Moe
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis
| | | | - Brandon M Kistler
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Department of Nutrition and Health Science, Ball State University, Muncie.
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Kalantar-Zadeh K, Forfang D, Bakris G, Martin KJ, Moe SM, Sprague SM. Managing Phosphate Burden in Patients Receiving Dialysis: Beyond Phosphate Binders and Diet. KIDNEY360 2023; 4:1650-1656. [PMID: 37870525 PMCID: PMC10695651 DOI: 10.34067/kid.0000000000000262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 09/07/2023] [Indexed: 10/24/2023]
Abstract
Most patients receiving dialysis rely on dietary restriction and phosphate binders to minimize the risk of hyperphosphatemia, which is associated with increased mortality. However, dietary restriction is difficult because of hidden phosphate additives in processed foods and medications. Restriction of dietary phosphate sources such as protein may increase the risk of malnutrition. Phosphate binders, the only pharmacologic option for phosphate management since aluminum salts were introduced several decades ago, are often insufficient for binding the 1400-2500 mg of phosphate potentially consumed daily. Over the last decade, serum phosphate levels in the United States have risen, and >69% of patients receiving dialysis exhibited a most recent phosphate level >4.5 mg/dl (above the normal range), indicating an urgent need for new, more effective therapies to manage phosphate burden. Novel, nonbinder therapies such as transcellular and paracellular phosphate absorption inhibitors may be used for phosphate management, and future studies should examine whether they allow fewer dietary restrictions for patients receiving dialysis, potentially improving patient quality of life and nutritional status. It is imperative that we collaborate to move beyond the restrictive approaches available today and provide patients and clinicians with an array of strategies so that they may choose the most appropriate patient-centered therapy.
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Affiliation(s)
- Kamyar Kalantar-Zadeh
- Division of Nephrology, Hypertension and Kidney Transplantation, University of California Irvine, Irvine, California
| | - Derek Forfang
- The Co-Chair of the National Forum of ESRD Network's Kidney Patient Advisory Council (KPAC), Henrico, Virginia
- National Kidney Foundation, Public Policy Committee, New York, New York
| | - George Bakris
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Chicago, Chicago, Illinois
| | - Kevin J. Martin
- Department of Internal Medicine, Division of Nephrology, Saint Louis University School of Medicine, St. Louis, Missouri
| | - Sharon M. Moe
- Division of Nephrology and Hypertension, Indiana University School of Medicine, Indianapolis, Indiana
| | - Stuart M. Sprague
- Division of Nephrology and Hypertension, NorthShore University Health System-University of Chicago Pritzker School of Medicine, Evanston, Illinois
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23
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Zachos NC, Vaughan H, Sarker R, Est-Witte S, Chakraborty M, Baetz NW, Yu H, Yarov-Yarovoy V, McNamara G, Green JJ, Tse CM, Donowitz M. A Novel Peptide Prevents Enterotoxin- and Inflammation-Induced Intestinal Fluid Secretion by Stimulating Sodium-Hydrogen Exchanger 3 Activity. Gastroenterology 2023; 165:986-998.e11. [PMID: 37429363 PMCID: PMC11283679 DOI: 10.1053/j.gastro.2023.06.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/05/2023] [Accepted: 06/09/2023] [Indexed: 07/12/2023]
Abstract
BACKGROUND & AIMS Acute diarrheal diseases are the second most common cause of infant mortality in developing countries. This is contributed to by lack of effective drug therapy that shortens the duration or lessens the volume of diarrhea. The epithelial brush border sodium (Na+)/hydrogen (H+) exchanger 3 (NHE3) accounts for a major component of intestinal Na+ absorption and is inhibited in most diarrheas. Because increased intestinal Na+ absorption can rehydrate patients with diarrhea, NHE3 has been suggested as a potential druggable target for drug therapy for diarrhea. METHODS A peptide (sodium-hydrogen exchanger 3 stimulatory peptide [N3SP]) was synthesized to mimic the part of the NHE3 C-terminus that forms a multiprotein complex that inhibits NHE3 activity. The effect of N3SP on NHE3 activity was evaluated in NHE3-transfected fibroblasts null for other plasma membrane NHEs, a human colon cancer cell line that models intestinal absorptive enterocytes (Caco-2/BBe), human enteroids, and mouse intestine in vitro and in vivo. N3SP was delivered into cells via a hydrophobic fluorescent maleimide or nanoparticles. RESULTS N3SP uptake stimulated NHE3 activity at nmol/L concentrations under basal conditions and partially reversed the reduced NHE3 activity caused by elevated adenosine 3',5'-cyclic monophosphate, guanosine 3',5'-cyclic monophosphate, and Ca2+ in cell lines and in in vitro mouse intestine. N3SP also stimulated intestinal fluid absorption in the mouse small intestine in vivo and prevented cholera toxin-, Escherichia coli heat-stable enterotoxin-, and cluster of differentiation 3 inflammation-induced fluid secretion in a live mouse intestinal loop model. CONCLUSIONS These findings suggest pharmacologic stimulation of NHE3 activity as an efficacious approach for the treatment of moderate/severe diarrheal diseases.
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Affiliation(s)
- Nicholas C Zachos
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
| | - Hannah Vaughan
- Translational Tissue Engineering Center, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Rafiquel Sarker
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Savannah Est-Witte
- Translational Tissue Engineering Center, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Molee Chakraborty
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Nicholas W Baetz
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Hongzhe Yu
- Translational Tissue Engineering Center, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California Davis, Davis, California; Department of Anesthesiology and Pain Medicine, University of California Davis, Davis, California
| | - George McNamara
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jordan J Green
- Translational Tissue Engineering Center, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Chung-Ming Tse
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Mark Donowitz
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
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Luo H, Feng J, Zhang Y, Wang J, Xue G, Huang X, You S, Dong H, Li L, Li J, Xiao H, Ai X, Li X, Huang B. Efficacy and safety of tenapanor in hemodialysis patients with hyperphosphatemia: A systematic review and meta-analysis of randomized placebo-controlled trials. Ther Apher Dial 2023; 27:839-847. [PMID: 37349983 DOI: 10.1111/1744-9987.14028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/30/2023] [Accepted: 06/13/2023] [Indexed: 06/24/2023]
Abstract
BACKGROUND The effects of tenapanor in reducing serum phosphorus in hemodialysis patients with hyperphosphatemia are uncertain and no relevant meta-analysis has been conducted. We performed a meta-analysis of randomized placebo-controlled trials to evaluate the efficacy and safety of tenapanor. METHODS All randomized controlled trials of tenapanor were searched up to 1 August 2022. The primary endpoint was the change in serum phosphorus level from baseline with tenapanor and placebo. Data on drug-related adverse events (AEs), gastrointestinal AEs and diarrhea were collected to determine the safety of tenapanor. RESULTS There were 533 patients throughout five trials that were eligible. Tenapanor significantly lowered blood phosphorus level by 1.79 mg/dl in the mean difference than the placebo. Diarrhea, gastrointestinal AEs, and drug-related AEs were more severe than placebo. CONCLUSIONS This meta-analysis showed that although drug side effects were common, tenapanor significantly reduced serum phosphorus level in hemodialysis patients.
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Affiliation(s)
- Houli Luo
- Department of Radiology, Cheng du First People's Hospital, Chengdu, Sichuan, China
| | - Jian Feng
- Department of Critical Care Medicine, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Yanbiao Zhang
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Jie Wang
- Department of Critical Care Medicine, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Gang Xue
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Xi Huang
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Shuang You
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Hongfei Dong
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Lingfan Li
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Juncheng Li
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Hualin Xiao
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Xiang Ai
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Xianhui Li
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Bo Huang
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, Sichuan, China
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Cernaro V, Longhitano E, Calabrese V, Casuscelli C, Di Carlo S, Spinella C, Gembillo G, Santoro D. Progress in pharmacotherapy for the treatment of hyperphosphatemia in renal failure. Expert Opin Pharmacother 2023; 24:1737-1746. [PMID: 37527180 DOI: 10.1080/14656566.2023.2243817] [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: 03/11/2023] [Revised: 07/26/2023] [Accepted: 07/31/2023] [Indexed: 08/03/2023]
Abstract
INTRODUCTION Among the clinical and metabolic complications of progressive chronic kidney disease (CKD), CKD-mineral bone disorder (CKD-MBD) significantly contributes to morbidity and mortality. While overt and persistent hyperphosphatemia is typical of advanced CKD and requires treatment, other abnormalities of calcium/phosphate metabolism begin to occur since the early stages of the disease. AREAS COVERED We searched on the PubMed database, without restrictions for language or time range, for randomized clinical trials and meta-analyses investigating phosphate-lowering therapies. The various phosphate binders show different safety profiles and diverse effects on calcium/phosphate metabolism and vascular calcification. The in-depth knowledge of the characteristics of these drugs is crucial to ensure adequate treatment to CKD patients. EXPERT OPINION A proper control of serum phosphate can be achieved using phosphate binders. These medications may induce side effects. Moreover, data on their impact on clinical outcomes are partly controversial or scarce, especially for the new generation drugs. Hyperphosphatemia favors cardiovascular disease and increases the risk for CKD progression. These effects are partially mediated by fibroblast growth factor 23 (FGF23), a phosphaturic hormone that raises to maintain normal serum phosphate. Since there are no data supporting the use of phosphate-lowering agents when phosphataemia is normal, a key role is played by reducing dietary phosphate intake with the aim to control serum phosphate and the compensatory FGF23 and parathyroid hormone (PTH) increase.
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Affiliation(s)
- Valeria Cernaro
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Elisa Longhitano
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Vincenzo Calabrese
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Chiara Casuscelli
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Silvia Di Carlo
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Claudia Spinella
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Guido Gembillo
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Domenico Santoro
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
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26
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Luo H, Feng J, Xue G, Zhang Y, Li Y, Huang X, Chen X, You S, Dong H, Li L, Li J, Xiao H, Ai X, Li X, Huang B. Comparative Efficacy and Acceptability of 12 Phosphorus-Lowering Drugs in Adults with Hyperphosphatemia and Chronic Kidney Disease: A Systematic Review and Network Meta-Analysis. Blood Purif 2023; 52:609-620. [PMID: 37591223 DOI: 10.1159/000531577] [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: 11/20/2022] [Accepted: 06/09/2023] [Indexed: 08/19/2023]
Abstract
BACKGROUND Hyperphosphatemia is associated with cardiovascular morbidity and mortality in adults with chronic kidney disease (CKD). Drug therapy has an irreplaceable role in the management of hyperphosphatemia. OBJECTIVES We aimed to compare and rank phosphorus-lowering drugs, including phosphate binder and nonphosphate binder, in hyperphosphatemia adults with CKD. METHODS We did a systematic review and frequentist random-effect network meta-analysis. We searched in PubMed, Cochrane Library, Web of Science, and Embase from inception to February 1, 2023, for randomized controlled trials of 12 phosphorus-lowering drugs in adults with hyperphosphatemia and CKD. Primary outcomes were efficacy (changes in serum phosphorus) and acceptability (treatment withdrawals due to any cause). We ranked each drug according to the value of surface under the cumulative ranking curve. We applied the Confidence in Network Meta-Analysis frameworks to rate the certainty of evidence. This study was registered with PROSPERO, number CRD42022322270. RESULTS We identified 2,174 citations, and of these, we included 94 trials comprising 14,459 participants and comparing 13 drugs or placebo. In terms of efficacy, except for niacinamide, all drugs lowered the level of serum phosphorus compared with placebo, with mean difference ranging between -1.61 (95% credible interval [CrI], -2.60 to -0.62) mg/dL for magnesium carbonate and -0.85 (-1.66 to -0.05) mg/dL for bixalomer. Only ferric citrate with odds ratios 0.56 (95% CrI: 0.36-0.89) was significantly associated with fewer dropouts for acceptability. Of the 94 trials, 43 (46%), 7 (7%), and 44 (47%) trials were rated as high, moderate, and low risk of bias, respectively, the certainty of the evidence was moderate to very low. CONCLUSIONS Magnesium carbonate has the best phosphorus-lowering effect in hyperphosphatemia adults with CKD; considering efficacy and acceptability, ferric citrate shows evidence to be the most appropriate drug with or without dialysis.
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Affiliation(s)
- Houli Luo
- Department of Radiology, Chengdu First People's Hospital, Chengdu, China
| | - Jian Feng
- Department of Critical Care Medicine, The General Hospital of Western Theater Command, Chengdu, China
| | - Gang Xue
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, China
| | - Yanbiao Zhang
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, China
| | - Yunming Li
- Department of Information, The General Hospital of Western Theater Command, Chengdu, China
| | - Xi Huang
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, China
| | - Xin Chen
- Department of Neurosurgery, The General Hospital of Western Theater Command, Chengdu, China
| | - Shuang You
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, China
| | - Hongfei Dong
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, China
| | - Lingfan Li
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, China
| | - Juncheng Li
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, China
| | - Hualin Xiao
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, China
| | - Xiang Ai
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, China
| | - Xianhui Li
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, China
| | - Bo Huang
- Department of Burn and Plastic, The General Hospital of Western Theater Command, Chengdu, China
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27
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Beggs MR, Young K, Plain A, O'Neill DD, Raza A, Flockerzi V, Dimke H, Alexander RT. Maternal Epidermal Growth Factor Promotes Neonatal Claudin-2 Dependent Increases in Small Intestinal Calcium Permeability. FUNCTION 2023; 4:zqad033. [PMID: 37575484 PMCID: PMC10413934 DOI: 10.1093/function/zqad033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 06/01/2023] [Accepted: 06/12/2023] [Indexed: 08/15/2023] Open
Abstract
A higher concentration of calcium in breast milk than blood favors paracellular calcium absorption enabling growth during postnatal development. We aimed to determine whether suckling animals have greater intestinal calcium permeability to maximize absorption and to identify the underlying molecular mechanism. We examined intestinal claudin expression at different ages in mice and in human intestinal epithelial (Caco-2) cells in response to hormones or human milk. We also measured intestinal calcium permeability in wildtype, Cldn2 and Cldn12 KO mice and Caco-2 cells in response to hormones or human milk. Bone mineralization in mice was assessed by μCT. Calcium permeability across the jejunum and ileum of mice were 2-fold greater at 2 wk than 2 mo postnatal age. At 2 wk, Cldn2 and Cldn12 expression were greater, but only Cldn2 KO mice had decreased calcium permeability compared to wildtype. This translated to decreased bone volume, cross-sectional thickness, and tissue mineral density of femurs. Weaning from breast milk led to a 50% decrease in Cldn2 expression in the jejunum and ileum. Epidermal growth factor (EGF) in breast milk specifically increased only CLDN2 expression and calcium permeability in Caco-2 cells. These data support intestinal permeability to calcium, conferred by claudin-2, being greater in suckling mice and being driven by EGF in breast milk. Loss of the CLDN2 pathway leads to suboptimal bone mineralization at 2 wk of life. Overall, EGF-mediated control of intestinal claudin-2 expression contributes to maximal intestinal calcium absorption in suckling animals.
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Affiliation(s)
- Megan R Beggs
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada
- The Women's & Children's Health Research Institute, Edmonton, AB T6G 1C9, Canada
| | - Kennedi Young
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Allen Plain
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Debbie D O'Neill
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Ahsan Raza
- Experimentelle und Klinische Pharmakologie und Toxikologie, Saarland University, 66421 Homburg, Germany
| | - Veit Flockerzi
- Experimentelle und Klinische Pharmakologie und Toxikologie, Saarland University, 66421 Homburg, Germany
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense C DK-5000, Demark
- Department of Nephrology, Odense University Hospital, 5000 Odense C, Denmark
| | - R Todd Alexander
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada
- The Women's & Children's Health Research Institute, Edmonton, AB T6G 1C9, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB T6G 1C9, Canada
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28
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The Association between Admission Serum Phosphorus and Preoperative Deep Venous Thrombosis in Geriatric Hip Fracture: A Retrospective Study. Diagnostics (Basel) 2023; 13:diagnostics13030545. [PMID: 36766651 PMCID: PMC9914597 DOI: 10.3390/diagnostics13030545] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 12/30/2022] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE This study aimed to evaluate the association between serum phosphorus level and preoperative deep vein thrombosis (DVT) in geriatric hip fractures. METHODS Older adults with hip fractures were screened between January 2015 and September 2019. Demographic and clinical characteristics of the patients were collected. Multivariate binary logistic regression and generalized additive models were used to identify the linear and nonlinear associations between serum phosphorus levels and preoperative DVT. Analyses were performed using Empower Stats and R software. RESULTS In this study, 1818 patients were included, with an average age of 79.39 ± 6.87. Of these, 30.25% were males, and 580 patients had DVT. The study found that when serum phosphorus was used as a continuous variable, there was a statistically significant difference in the relationship between blood phosphorus and the occurrence of DVT (p < 0.05). Furthermore, we also found curvilinear relationships. Serum phosphorus = 0.71 mmol/L was the inflection point in the curve. When serum phosphorus was <0.71 mmol/L, the serum phosphorus was associated with DVT (OR = 1.64; 95% CI: 1.04-2.59; p = 0.0333). With a 0.1 mmol/L increase, the DVT increased 0.64 times. When phosphorus was >0.71 mmol/L, there was no significant difference in the correlation between serum phosphorus levels and DVT (OR = 1.03; 95% CI: 0.98-1.09; p = 0.186). CONCLUSION Serum phosphorus was nonlinearly associated with preoperative DVT in geriatric patients with hip fractures, and serum phosphorus level could be considered a predictor of DVT risk.
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Dwyer JP, Kelepouris E. New Directions in Phosphorus Management in Dialysis. J Ren Nutr 2023; 33:12-16. [PMID: 35597321 DOI: 10.1053/j.jrn.2022.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 03/07/2022] [Accepted: 04/24/2022] [Indexed: 01/25/2023] Open
Abstract
Current phosphate management strategies in end-stage renal disease (dietary phosphate restriction, dialysis, and phosphate binders) are inadequate to maintain target phosphate levels in most patients. Dietary phosphate restriction is challenging due to "hidden phosphates" in processed foods, and dialysis and phosphate binders are insufficient to match average dietary phosphate intake. As phosphate binders must be taken with each meal, patients need to ingest many, large pills several times a day, negatively impacting quality of life. Recent advances in our understanding of phosphate absorption pathways have led to the development of new nonbinder therapies that block phosphate absorption. This review describes the limitations of current phosphate management strategies and discusses new therapies in development that inhibit phosphate absorption pathways. These new therapies present an opportunity to rethink phosphate management, potentially by prescribing phosphate absorption inhibitors as a primary therapy and adding phosphate binders if needed.
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Affiliation(s)
- Jamie P Dwyer
- Professor of Medicine, Division of Nephrology & Hypertension, University of Utah, Salt Lake City, Utah.
| | - Ellie Kelepouris
- Professor of Clinical Medicine, Renal Electrolyte and Hypertension Division, University of Pennsylvania, Philadelphia, Pennsylvania
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30
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Walker V, Vuister GW. Biochemistry and pathophysiology of the Transient Potential Receptor Vanilloid 6 (TRPV6) calcium channel. Adv Clin Chem 2023; 113:43-100. [PMID: 36858649 DOI: 10.1016/bs.acc.2022.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
TRPV6 is a Transient Receptor Potential Vanilloid (TRPV) cation channel with high selectivity for Ca2+ ions. First identified in 1999 in a search for the gene which mediates intestinal Ca2+ absorption, its far more extensive repertoire as a guardian of intracellular Ca2+ has since become apparent. Studies on TRPV6-deficient mice demonstrated additional important roles in placental Ca2+ transport, fetal bone development and male fertility. The first reports of inherited deficiency in newborn babies appeared in 2018, revealing its physiological importance in humans. There is currently strong evidence that TRPV6 also contributes to the pathogenesis of some common cancers. The recently reported association of TRPV6 deficiency with non-alcoholic chronic pancreatitis suggests a role in normal pancreatic function. Over time and with greater awareness of TRPV6, other disease-associations are likely to emerge. Powerful analytical tools have provided invaluable insights into the structure and operation of TRPV6. Its roles in Ca2+ signaling and carcinogenesis, and the use of channel inhibitors in cancer treatment are being intensively investigated. This review first briefly describes the biochemistry and physiology of the channel, and analytical methods used to investigate these. The focus subsequently shifts to the clinical disorders associated with abnormal expression and the underlying pathophysiology. The aims of this review are to increase awareness of this channel, and to draw together findings from a wide range of sources which may help to formulate new ideas for further studies.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton, United Kingdom.
| | - Geerten W Vuister
- Department of Molecular and Cell Biology, Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, United Kingdom
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31
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Mazurek B, Hesse G, Sattel H, Kratzsch V, Lahmann C, Dobel C. S3 Guideline: Chronic Tinnitus : German Society for Otorhinolaryngology, Head and Neck Surgery e. V. (DGHNO-KHC). HNO 2022; 70:795-827. [PMID: 36227338 PMCID: PMC9581878 DOI: 10.1007/s00106-022-01207-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2022] [Indexed: 11/16/2022]
Affiliation(s)
- Birgit Mazurek
- Tinnituszentrum, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
| | - Gerhard Hesse
- Tinnitus-Klinik, KH Bad Arolsen, Große Allee 50, 34454, Bad Arolsen, Germany.
- Universität Witten/Herdecke, Witten, Germany.
| | - Heribert Sattel
- Klinikum rechts der Isar, Klinik und Poliklinik für Psychosomatische Medizin und Psychotherapie, Technical University of Munich, Langerstr. 3, 81675, Munich, Germany
| | - Volker Kratzsch
- Abt. Hörbehinderung, Tinnitus und Schwindelerkrankungen, VAMED Rehaklinik Bad Grönenbach, Sebastian-Kneipp-Allee 3-5, 87730, Bad Grönenbach, Germany
| | - Claas Lahmann
- Klinik für Psychosomatische Medizin und Psychotherapie, Universitätsklinikum Freiburg, Hauptstr. 8, 79104, Freiburg, Germany
| | - Christian Dobel
- Klinik für Hals-, Nasen- und Ohrenheilkunde, Universitätsklinikum Jena, Am Klinikum 1, 07747, Jena, Germany
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32
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Verbueken D, Moe OW. Strategies to lower fibroblast growth factor 23 bioactivity. Nephrol Dial Transplant 2022; 37:1800-1807. [PMID: 33502502 PMCID: PMC9494132 DOI: 10.1093/ndt/gfab012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Indexed: 12/26/2022] Open
Abstract
Fibroblast growth factor 23 (FGF23) is a circulating hormone derived from the bone whose release is controlled by many factors and exerts a multitude of systemic actions. There are congenital and acquired disorders of increased and decreased FGF23 levels. In chronic kidney disease (CKD), elevations of FGF23 levels can be 1000-fold above the upper physiological limit. It is still debated whether this high FGF23 in CKD is a biomarker or causally related to morbidity and mortality. Data from human association studies support pathogenicity, while experimental data are less robust. Knowledge of the biology and pathobiology of FGF23 has generated a plethora of means to reduce FGF23 bioactivity at many levels that will be useful for therapeutic translations. This article summarizes these approaches and addresses several critical questions that still need to be answered.
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Affiliation(s)
- Devin Verbueken
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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Sodium phosphate cotransporter 2a inhibitors: potential therapeutic uses. Curr Opin Nephrol Hypertens 2022; 31:486-492. [PMID: 35894284 PMCID: PMC9387751 DOI: 10.1097/mnh.0000000000000828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE OF REVIEW Targeting sodium phosphate cotransporter 2a (Npt2a) offers a novel strategy for treating hyperphosphatemia in chronic kidney disease (CKD). Here we review recent studies on the efficacy of Npt2a inhibition, its plasma phosphate (Pi)-lowering effects, as well as potential "off-target" beneficial effects on cardiovascular consequences. RECENT FINDINGS Two novel Npt2a-selective inhibitors (PF-06869206 and BAY-767) have been developed. Pharmacological Npt2a inhibition shows a significant phosphaturic effect and consequently lowers plasma Pi and parathyroid hormone (PTH) levels regardless of CKD. However, plasma fibroblast growth factor 23 (FGF23), a master regulator of Pi homeostasis, shows inconsistent responses between these two inhibitors (no effect by PF-06869206 vs. reduction by BAY-767). In addition to the effects on Pi homeostasis, Npt2a inhibition also enhances urinary excretions of Na+, Cl-, and Ca2+, which is recapitulated in animal models with reduced kidney function. The effect of Npt2a inhibition by BAY-767 on vascular calcification has been studied, with positive results showing that oral treatment with BAY-767 (10 mg kg-1) attenuated the increases in plasma Pi and Ca2+ content in the aorta under the setting of vascular calcification induced by a pan-FGF receptor inhibitor. Together, Npt2a inhibition offers a promising therapeutic approach for treating hyperphosphatemia and reducing cardiovascular complications in CKD. SUMMARY Npt2a inhibition significantly increases urinary Pi excretion and lowers plasma Pi and PTH levels; moreover, it exerts pleiotropic "off-target" effects, providing a novel treatment for hyperphosphatemia and exhibiting beneficial potential for cardiovascular complications in CKD.
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Pergola PE. Phosphate Frustration: Treatment Options to Complement Current Therapies. Int J Nephrol 2022; 2022:9457440. [PMID: 36045900 PMCID: PMC9424003 DOI: 10.1155/2022/9457440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 07/16/2022] [Indexed: 11/18/2022] Open
Abstract
Hyperphosphatemia eventually develops in almost all patients with advanced chronic kidney disease and is associated with negative clinical outcomes. Thus, guidelines recommend targeting treatment to normal phosphate levels in patients with chronic kidney disease. Despite low phosphorus diets, clearance by dialysis, and phosphate binder use, many patients with chronic kidney disease on dialysis are unable to consistently achieve and maintain serum phosphate concentrations <5.5 mg/dL. A chart audit of patients on dialysis receiving phosphate binders showed that 74 to 86% were unable to consistently achieve serum phosphate ≤5.5 mg/dL over 6 months. Furthermore, although there is evidence that serum phosphate concentrations <4.5 mg/dL are associated with improved survival and cardiovascular outcomes, real-world phosphate control data suggest achieving and maintaining this goal for most patients would be extremely challenging, if not near impossible, using current therapies. As phosphate binders can only remove approximately 300 mg of the 2,500 mg or more daily dietary phosphate intake, therapeutic innovations are necessary to improve phosphate management. We present treatment options to complement current therapies including tenapanor, a novel sodium/hydrogen exchanger isoform 3 inhibitor that blocks the dominant paracellular phosphate absorption pathway and has been shown to reduce phosphate levels in several clinical trials.
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Jiang X, Liu Y, Zhang XY, Liu X, Liu X, Wu X, Jose PA, Duan S, Xu FJ, Yang Z. Intestinal Gastrin/CCKBR (Cholecystokinin B Receptor) Ameliorates Salt-Sensitive Hypertension by Inhibiting Intestinal Na +/H + Exchanger 3 Activity Through a PKC (Protein Kinase C)-Mediated NHERF1 and NHERF2 Pathway. Hypertension 2022; 79:1668-1679. [PMID: 35674015 PMCID: PMC9278716 DOI: 10.1161/hypertensionaha.121.18791] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background: The present study directly tested the crucial role of intestinal gastrin/CCKBR (cholecystokinin B receptor) in the treatment of salt-sensitive hypertension. Methods: Adult intestine-specific Cckbr-knockout mice (Cckbrfl/flvillin-Cre) and Dahl salt-sensitive rats were studied on the effect of high salt intake (8% NaCl, 6–7 weeks) on intestinal Na+/H+ exchanger 3 expression, urine sodium concentration, and blood pressure. High-salt diet increased urine sodium concentration and systolic blood pressure to a greater extent in Cckbrfl/flvillin-Cre mice and Dahl salt-sensitive rats than their respective controls, Cckbrfl/flvillin mice and SS13BN rats. We constructed gastrin-SiO2 microspheres to enable gastrin to stimulate specifically and selectively intestinal CCKBR without its absorption into the circulation. Results: Gastrin-SiO2 microspheres treatment prevented the high salt-induced hypertension and increase in urine Na concentration by inhibiting intestinal Na+/H+ exchanger 3 trafficking and activity, increasing stool sodium without inducing diarrhea. Gastrin-mediated inhibition of intestinal Na+/H+ exchanger 3 activity, related to a PKC (protein kinase C)-mediated activation of NHERF1 and NHERF2. Conclusions: These results support a crucial role of intestinal gastrin/CCKBR in decreasing intestinal sodium absorption and keeping the blood pressure in the normal range. The gastrointestinal administration of gastrin-SiO2 microspheres is a promising and safe strategy to treat salt-sensitive hypertension without side effects.
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Affiliation(s)
- Xiaoliang Jiang
- NHC Key Laboratory of Human Disease Comparative Medicine (The Institute of Laboratory Animal Sciences, CAMS&PUMC), National Human Diseases Animal Model Resource Center, Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, P.R. China (X.J., Y.L., Xue Liu, Xing Liu, X.W., Z.Y.)
| | - Yunpeng Liu
- NHC Key Laboratory of Human Disease Comparative Medicine (The Institute of Laboratory Animal Sciences, CAMS&PUMC), National Human Diseases Animal Model Resource Center, Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, P.R. China (X.J., Y.L., Xue Liu, Xing Liu, X.W., Z.Y.)
| | - Xin-Yang Zhang
- Key Lab of Biomedical Materials of Natural Macromolecules (Beijing University of Chemical Technology), Ministry of Education, Beijing Laboratory of Biomedical Materials, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, P.R. China (X.-Y.Z., S.D., F.-J.X.)
| | - Xue Liu
- NHC Key Laboratory of Human Disease Comparative Medicine (The Institute of Laboratory Animal Sciences, CAMS&PUMC), National Human Diseases Animal Model Resource Center, Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, P.R. China (X.J., Y.L., Xue Liu, Xing Liu, X.W., Z.Y.)
| | - Xing Liu
- NHC Key Laboratory of Human Disease Comparative Medicine (The Institute of Laboratory Animal Sciences, CAMS&PUMC), National Human Diseases Animal Model Resource Center, Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, P.R. China (X.J., Y.L., Xue Liu, Xing Liu, X.W., Z.Y.)
| | - Xianxian Wu
- NHC Key Laboratory of Human Disease Comparative Medicine (The Institute of Laboratory Animal Sciences, CAMS&PUMC), National Human Diseases Animal Model Resource Center, Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, P.R. China (X.J., Y.L., Xue Liu, Xing Liu, X.W., Z.Y.)
| | - Pedro A Jose
- Department of Pharmacology and Physiology (P.A.J.), The George Washington University School of Medicine and Health Sciences, Washington, DC.,Division of Kidney Diseases and Hypertension, Department of Medicine (P.A.J.), The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Shun Duan
- Key Lab of Biomedical Materials of Natural Macromolecules (Beijing University of Chemical Technology), Ministry of Education, Beijing Laboratory of Biomedical Materials, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, P.R. China (X.-Y.Z., S.D., F.-J.X.)
| | - Fu-Jian Xu
- Key Lab of Biomedical Materials of Natural Macromolecules (Beijing University of Chemical Technology), Ministry of Education, Beijing Laboratory of Biomedical Materials, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, P.R. China (X.-Y.Z., S.D., F.-J.X.)
| | - Zhiwei Yang
- NHC Key Laboratory of Human Disease Comparative Medicine (The Institute of Laboratory Animal Sciences, CAMS&PUMC), National Human Diseases Animal Model Resource Center, Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, P.R. China (X.J., Y.L., Xue Liu, Xing Liu, X.W., Z.Y.)
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Abstract
Phosphate homeostasis is dependent on the interaction and coordination of four main organ systems: thyroid/parathyroids, gastrointestinal tract, bone and kidneys, and three key hormonal regulators, 1,25-hydroxyvitamin D3, parathyroid hormone and FGF23 with its co- factor klotho. Phosphorus is a critical nutritional element for normal cellular function, but in excess can be toxic to tissues, particularly the vasculature. As phosphate, it also has an important interaction and inter-dependence with calcium and calcium homeostasis sharing some of the same controlling hormones, although this is not covered in our article. We have chosen to provide a current overview of phosphate homeostasis only, focusing on the role of two major organ systems, the gastrointestinal tract and kidneys, and their contribution to the control of phosphate balance. We describe in some detail the mechanisms of intestinal and renal phosphate transport, and compare and contrast their regulation. We also consider a significant example of phosphate imbalance, with phosphate retention, which is chronic kidney disease; why consequent hyperphosphatemia is important, and some of the newer means of managing it.
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Affiliation(s)
- Joanne Marks
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Robert J Unwin
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom; Department of Renal Medicine, University College London, London, United Kingdom.
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Duque EJ, Elias RM, Moysés RMA. Phosphate balance during dialysis and after kidney transplantation in patients with chronic kidney disease. Curr Opin Nephrol Hypertens 2022; 31:326-331. [PMID: 35703226 DOI: 10.1097/mnh.0000000000000802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW In patients with chronic kidney disease (CKD), hyperphosphatemia is associated with several adverse outcomes, including bone fragility and progression of kidney and cardiovascular disease. However, there is a knowledge gap regarding phosphate balance in CKD. This review explores its current state, depending on the stage of CKD, dialysis modalities, and the influence of kidney transplantation. RECENT FINDINGS Adequate phosphate control is one of the goals of treatment for CKD-mineral and bone disorder. However, ongoing studies are challenging the benefits of phosphate-lowering treatment. Nevertheless, the current therapy is based on dietary restriction, phosphate binders, and optimal removal by dialysis. In the face of limited adherence, due to the high pill burden, adjuvant options are under investigation. The recent discovery that intestinal absorption of phosphate is mostly paracellular when the intraluminal concentration is adequate might help explain why phosphate is still well absorbed in CKD, despite the lower levels of calcitriol. SUMMARY Future studies could confirm the benefits of phosphate control. Greater understanding of the complex distribution of phosphate among the body compartments will help us define a better therapeutic strategy in patients with CKD.
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Affiliation(s)
- Eduardo J Duque
- Laboratorio de Fisiopatologia Renal LIM16, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo
| | - Rosilene M Elias
- Laboratorio de Fisiopatologia Renal LIM16, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo
- Postgraduate Program in Medicine, Nove de Julho University, São Paulo, SP, Brazil
| | - Rosa M A Moysés
- Laboratorio de Fisiopatologia Renal LIM16, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo
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Jacobs JW, Leadbetter MR, Bell N, Koo-McCoy S, Carreras CW, He L, Kohler J, Kozuka K, Labonté ED, Navre M, Spencer AG, Charmot D. Discovery of Tenapanor: A First-in-Class Minimally Systemic Inhibitor of Intestinal Na +/H + Exchanger Isoform 3. ACS Med Chem Lett 2022; 13:1043-1051. [PMID: 35859876 PMCID: PMC9290029 DOI: 10.1021/acsmedchemlett.2c00037] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
![]()
We present herein
the design, synthesis, and optimization of gut-restricted
inhibitors of Na+/H+ exchanger isoform 3 (NHE3).
NHE3 is predominantly expressed in the kidney and gastrointestinal
tract where it acts as the major absorptive sodium transporter. We
desired minimally systemic agents that would block sodium absorption
in the gastrointestinal tract but avoid exposure in the kidney. Starting
with a relatively low-potency highly bioavailable hit compound (1), potent and minimally absorbed NHE3 inhibitors were designed,
culminating with the discovery of tenapanor (28). Tenapanor
has been approved by the U.S. Food and Drug Administration (FDA) for
the treatment of irritable bowel syndrome with constipation in adults.
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Affiliation(s)
- Jeffrey W. Jacobs
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Michael R. Leadbetter
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Noah Bell
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Samantha Koo-McCoy
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | | | - Limin He
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Jill Kohler
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Kenji Kozuka
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Eric D. Labonté
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Marc Navre
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Andrew G. Spencer
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Dominique Charmot
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
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Wang X, Xu Y, Yu X, Dey A, Zhang HY, Zink CM, Wodka D, Porter G, Matter WF, Porras L, Reidy CA, Peterson JA, Mattioni BE, Haas JV, Kowala MC, Wetterau JR. Effects of pharmacological inhibition of the sodium-dependent phosphate cotransporter 2b (NPT2b) on intestinal phosphate absorption in mouse and rat models. Pharmacol Res Perspect 2022; 10:e00938. [PMID: 35194979 PMCID: PMC8863579 DOI: 10.1002/prp2.938] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 01/25/2022] [Accepted: 01/27/2022] [Indexed: 11/08/2022] Open
Abstract
An excess phosphate burden in renal disease has pathological consequences for bone, kidney, and heart. Therapies to decrease intestinal phosphate absorption have been used to address the problem, but with limited success. Here, we describe the in vivo effects of a novel potent inhibitor of the intestinal sodium-dependent phosphate cotransporter NPT2b, LY3358966. Following treatment with LY3358966, phosphate uptake into plasma 15 min following an oral dose of radiolabeled phosphate was decreased 74% and 22% in mice and rats, respectively, indicating NPT2b plays a much more dominant role in mice than rats. Following the treatment with LY3358966 and radiolabeled phosphate, mouse feces were collected for 48 h to determine the ability of LY3358966 to inhibit phosphate absorption. Compared to vehicle-treated animals, there was a significant increase in radiolabeled phosphate recovered in feces (8.6% of the dose, p < .0001). Similar studies performed in rats also increased phosphate recovered in feces (5.3% of the dose, p < .05). When used in combination with the phosphate binder sevelamer in rats, there was a further small, but not significant, increase in fecal phosphate. In conclusion, LY3358966 revealed a more prominent role for NPT2b on acute intestinal phosphate uptake into plasma in mice than rats. However, the modest effects on total intestinal phosphate absorption observed in mice and rats with LY3359866 when used alone or in combination with sevelamer highlights the challenge to identify new more effective therapeutic targets and/or drug combinations to treat the phosphate burden in patients with renal disease.
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Affiliation(s)
- Xiaojun Wang
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - Yanping Xu
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - Xiaohong Yu
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - Asim Dey
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - Hong Y. Zhang
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - Charity M. Zink
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - Derek Wodka
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - Gina Porter
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - William F. Matter
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - Leah Porras
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - Charles A. Reidy
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | | | - Brian E. Mattioni
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - Joseph V. Haas
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - Mark C. Kowala
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
| | - John R. Wetterau
- Lilly Research LaboratoriesEli Lilly and CompanyIndianapolisIndianaUSA
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Ogata H, Takeshima A, Ito H. An update on phosphate binders for the treatment of hyperphosphatemia in chronic kidney disease patients on dialysis: a review of safety profiles. Expert Opin Drug Saf 2022; 21:947-955. [PMID: 35180026 DOI: 10.1080/14740338.2022.2044472] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
INTRODUCTION Hyperphosphatemia is an inevitable complication for patients undergoing dialysis, as is the resulting need for treatment with phosphate binders. Currently, various phosphate binders are clinically available. In addition to their phosphate-lowering activity, individual phosphate binders have differing safety profiles and off-target actions. AREAS COVERED This paper reviews the safety of phosphate binders and issues to be resolved. EXPERT OPINION Calcium-based phosphate binders are well tolerated but may increase calcium overload risk. Sevelamer reduces serum cholesterol levels and exerts anti-inflammatory effects. Compared to sevelamer, bixalomer is associated with fewer gastrointestinal symptoms. Aluminum-containing binders, lanthanum carbonate, and sucroferric oxyhydroxide exhibit strong phosphate-lowering activity. Although ferric citrate reduces erythropoiesis-stimulating agents and intravenous iron doses, its use requires monitoring of iron metabolic markers to avoid overload. Occasionally, combined use of multiple phosphate binders can offer the advantages of each phosphate binder while minimizing their drawbacks; thus, this may be desirable according to individual patients' conditions and comorbidities. However, increased pill burden and nonadherence to phosphate binders emerge as new problems. We expect that novel therapeutic strategies will be developed to resolve these issues.
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Affiliation(s)
- Hiroaki Ogata
- Division of Nephrology, Department of Internal Medicine, Showa University, Northern Yokohama Hospital, Chigasaki-chuo 35-1, Tsuzuki, Yokohama 2248503, JAPAN
| | - Akiko Takeshima
- Division of Nephrology, Department of Internal Medicine, Showa University, Northern Yokohama Hospital, Chigasaki-chuo 35-1, Tsuzuki, Yokohama 2248503, JAPAN
| | - Hidetoshi Ito
- Division of Nephrology, Department of Internal Medicine, Showa University, Northern Yokohama Hospital, Chigasaki-chuo 35-1, Tsuzuki, Yokohama 2248503, JAPAN
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41
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Xue J, Thomas L, Murali SK, Levi M, Fenton RA, Dominguez Rieg JA, Rieg T. Enhanced phosphate absorption in intestinal epithelial cell-specific NHE3 knockout mice. Acta Physiol (Oxf) 2022; 234:e13756. [PMID: 34978760 PMCID: PMC9286053 DOI: 10.1111/apha.13756] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/16/2021] [Accepted: 01/01/2022] [Indexed: 12/11/2022]
Abstract
Aims The kidneys play a major role in maintaining Pi homeostasis. Patients in later stages of CKD develop hyperphosphatemia. One novel treatment option is tenapanor, an intestinal‐specific NHE3 inhibitor. To gain mechanistic insight into the role of intestinal NHE3 in Pi homeostasis, we studied tamoxifen‐inducible intestinal epithelial cell‐specific NHE3 knockout (NHE3IEC‐KO) mice. Methods Mice underwent dietary Pi challenges, and hormones as well as urinary/plasma Pi were determined. Intestinal 33P uptake studies were conducted in vivo to compare the effects of tenapanor and NHE3IEC‐KO. Ex vivo Pi transport was measured in everted gut sacs and brush border membrane vesicles. Intestinal and renal protein expression of Pi transporters were determined. Results On the control diet, NHE3IEC‐KO mice had similar Pi homeostasis, but a ~25% reduction in FGF23 compared with control mice. Everted gut sacs and brush border membrane vesicles showed enhanced Pi uptake associated with increased Npt2b expression in NHE3IEC‐KO mice. Acute oral Pi loading resulted in higher plasma Pi in NHE3IEC‐KO mice. Tenapanor inhibited intestinal 33P uptake acutely but then led to hyper‐absorption at later time points compared to vehicle. In response to high dietary Pi, plasma Pi and FGF23 increased to higher levels in NHE3IEC‐KO mice which was associated with greater Npt2b expression. Reduced renal Npt2c and a trend for reduced Npt2a expression were unable to correct for higher plasma Pi. Conclusion Intestinal NHE3 has a significant contribution to Pi homeostasis. In contrast to effects described for tenapanor on Pi homeostasis, NHE3IEC‐KO mice show enhanced, rather than reduced, intestinal Pi uptake.
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Affiliation(s)
- Jianxiang Xue
- Department of Molecular Pharmacology and Physiology Morsani College of Medicine University of South Florida Tampa Florida USA
| | - Linto Thomas
- Department of Molecular Pharmacology and Physiology Morsani College of Medicine University of South Florida Tampa Florida USA
| | | | - Moshe Levi
- Department of Biochemistry and Molecular & Cellular Biology Georgetown University Washington District of Columbia USA
| | | | - Jessica A. Dominguez Rieg
- Department of Molecular Pharmacology and Physiology Morsani College of Medicine University of South Florida Tampa Florida USA
- James A. Haley Veterans' Hospital Tampa Florida USA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology Morsani College of Medicine University of South Florida Tampa Florida USA
- James A. Haley Veterans' Hospital Tampa Florida USA
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42
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Doshi SM, Wish JB. Past, Present, and Future of Phosphate Management. Kidney Int Rep 2022; 7:688-698. [PMID: 35497793 PMCID: PMC9039476 DOI: 10.1016/j.ekir.2022.01.1055] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/12/2022] [Accepted: 01/17/2022] [Indexed: 11/20/2022] Open
Abstract
Cardiovascular (CV) disease (CVD) accounts for >50% of deaths with known causes in patients on dialysis. Elevated serum phosphorus levels are an important nontraditional risk factor for bone mineral disease and CVD in patients with chronic kidney disease (CKD). Given that phosphorus concentrations drive other disorders associated with increased CV risk (e.g., endothelial dysfunction, vascular calcification, fibroblast growth factor-23, parathyroid hormone), phosphate is a logical target to improve CV health. Phosphate binders are the only pharmacologic treatment approved for hyperphosphatemia. Although their safety has improved since inception, the mechanism of action leads to characteristics that make ingestion difficult and unpleasant; large pill size, objectionable taste, and multiple pills required for each meal and snack make phosphate binders a burden. Side effects, especially those affecting the gastrointestinal (GI) system, are common with binders, often leading to treatment discontinuation. The presence of “hidden” phosphates in processed foods and certain medications makes phosphate management even more challenging. Owing to these significant issues, most patients on dialysis are not consistently achieving and maintaining target phosphorus concentrations of <5.5 mg/dl, let alone more normal levels of <4.5 mg/dl, indicating novel approaches to improve phosphate management and CV health are needed. Several new nonbinder therapies that target intestinal phosphate absorption pathways have been developed. These include EOS789, which acts on the transcellular pathway, and tenapanor, which targets the dominant paracellular pathway. As observational evidence has established a strong association between phosphorus concentration and clinical outcomes, such as mortality, phosphate is an important target for improving the health of patients with CKD and end-stage kidney disease (ESKD).
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43
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Npt2a as a target for treating hyperphosphatemia. Biochem Soc Trans 2022; 50:439-446. [PMID: 34994388 PMCID: PMC9022968 DOI: 10.1042/bst20211005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/08/2021] [Accepted: 12/13/2021] [Indexed: 12/04/2022]
Abstract
Hyperphosphatemia results from an imbalance in phosphate (Pi) homeostasis. In patients with and without reduced kidney function, hyperphosphatemia is associated with cardiovascular complications. The current mainstays in the management of hyperphosphatemia are oral Pi binder and dietary Pi restriction. Although these options are employed in patients with chronic kidney disease (CKD), they seem inadequate to correct elevated plasma Pi levels. In addition, a paradoxical increase in expression of intestinal Pi transporter and uptake may occur. Recently, studies in rodents targeting the renal Na+/Pi cotransporter 2a (Npt2a), responsible for ∼70% of Pi reabsorption, have been proposed as a potential treatment option. Two compounds (PF-06869206 and BAY-767) have been developed which are selective for Npt2a. These Npt2a inhibitors significantly increased urinary Pi excretion consequently lowering plasma Pi and PTH levels. Additionally, increases in urinary excretions of Na+, Cl− and Ca2+ have been observed. Some of these results are also seen in models of reduced kidney function. Responses of FGF23, a phosphaturic hormone that has been linked to the development of left ventricular hypertrophy in CKD, are ambiguous. In this review, we discuss the recent advances on the role of Npt2a inhibition on Pi homeostasis as well as other pleiotropic effects observed with Npt2a inhibition.
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Hu MC, Moe OW. Phosphate and Cellular Senescence. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1362:55-72. [PMID: 35288873 PMCID: PMC10513121 DOI: 10.1007/978-3-030-91623-7_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cellular senescence is one type of permeant arrest of cell growth and one of increasingly recognized contributor to aging and age-associated disease. High phosphate and low Klotho individually and synergistically lead to age-related degeneration in multiple organs. Substantial evidence supports the causality of high phosphate in cellular senescence, and potential contribution to human aging, cancer, cardiovascular, kidney, neurodegenerative, and musculoskeletal diseases. Phosphate can induce cellular senescence both by direct phosphotoxicity, and indirectly through downregulation of Klotho and upregulation of plasminogen activator inhibitor-1. Restriction of dietary phosphate intake and blockage of intestinal absorption of phosphate help suppress cellular senescence. Supplementation of Klotho protein, cellular senescence inhibitor, and removal of senescent cells with senolytic agents are potential novel strategies to attenuate phosphate-induced cellular senescence, retard aging, and ameliorate age-associated, and phosphate-induced disorders.
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Affiliation(s)
- Ming Chang Hu
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Orson W Moe
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Departments of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Kovesdy CP, Adebiyi A, Rosenbaum D, Jacobs JW, Quarles LD. Novel Treatments from Inhibition of the Intestinal Sodium-Hydrogen Exchanger 3. Int J Nephrol Renovasc Dis 2021; 14:411-420. [PMID: 34880650 PMCID: PMC8646223 DOI: 10.2147/ijnrd.s334024] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 11/11/2021] [Indexed: 12/31/2022] Open
Abstract
Plasma membrane sodium–hydrogen exchangers (NHE) transport Na+ into cells in exchange for H+. While there are nine isoforms of NHE in humans, this review focuses on the NHE3 isoform, which is abundantly expressed in the gastrointestinal tract, where it plays a key role in acid–base balance and water homeostasis. NHE3 inhibition in the small intestine results in luminal sodium and water retention, leading to a general decrease in paracellular water flux and diffusional driving force, reduced intestinal sodium absorption, and increased stool sodium excretion. The resulting softer and more frequent stools are the rationale for the development of tenapanor as a novel, first-in-class NHE3 inhibitor to treat irritable bowel syndrome with constipation. NHE3 also has additional therapeutic implications in nephrology. Inhibition of intestinal NHE3 also lowers blood pressure by reducing intestinal sodium absorption. Perhaps, the most novel effect is its ability to decrease intestinal phosphate absorption by inhibiting the paracellular phosphate absorption pathway. Therefore, selective pharmacological inhibition of NHE3 could be a potential therapeutic strategy to treat not only heart failure and hypertension but also hyperphosphatemia. This review presents an overview of the molecular and physiological functions of NHE3 and discusses how these functions translate to potential clinical applications in nephrology.
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Affiliation(s)
- Csaba P Kovesdy
- Division of Nephrology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Adebowale Adebiyi
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | | | | | - L Darryl Quarles
- Division of Nephrology, University of Tennessee Health Science Center, Memphis, TN, USA
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Ma Z, Hummel SL, Sun N, Chen Y. From salt to hypertension, what is missed? J Clin Hypertens (Greenwich) 2021; 23:2033-2041. [PMID: 34846798 PMCID: PMC8696232 DOI: 10.1111/jch.14402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/20/2021] [Accepted: 11/03/2021] [Indexed: 01/18/2023]
Abstract
Excess salt intake is viewed as a major contributor to hypertension and cardiovascular disease, and dietary salt restriction is broadly recommended by public health guidelines. However, individuals can have widely varying physiological responses to salt intake, and a tailored approach to evaluation and intervention may be needed. The traditional sodium related concepts are challenging to assess clinically for two reasons: (1) spot and 24-hour urine sodium are frequently used to evaluate salt intake, but are more suitable for population study, and (2) some adverse effects of salt may be blood pressure-independent. In recent years, previously unknown mechanisms of sodium absorption and storage have been discovered. This review will outline the limitations of current methods to assess sodium balance and discuss new potential evaluation methods and treatment targets.
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Affiliation(s)
- Zhiyi Ma
- Cardiology DepartmentBeijing Tsinghua Changgung HospitalSchool of Clinical MedicineTsinghua UniversityBeijingChina
| | - Scott L. Hummel
- Ann Arbor Veterans Affairs Health SystemUniversity of Michigan Frankel Cardiovascular CenterAnn ArborMichiganUSA
| | - Ningling Sun
- Cardiology DepartmentHeart CenterPeking University People's HospitalBeijingChina
| | - Yuanyuan Chen
- Cardiology DepartmentHeart CenterPeking University People's HospitalBeijingChina
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Fishbane SN, Nigwekar S. Phosphate Absorption and Hyperphosphatemia Management in Kidney Disease: A Physiology-Based Review. Kidney Med 2021; 3:1057-1064. [PMID: 34939015 PMCID: PMC8664730 DOI: 10.1016/j.xkme.2021.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Phosphate absorption occurs in the gastrointestinal tract through paracellular absorption and transcellular transport. The paracellular pathway does not saturate and has a significantly higher absorption capacity than does the transcellular pathway. Evidence indicates that this pathway is the primary mechanism of intestinal phosphate absorption, particularly with Western diets containing high amounts of phosphorus. Elevated serum phosphorus concentrations are associated with cardiovascular morbidity and mortality but serum phosphorus concentrations > 5.5 mg/dL are highly prevalent despite best efforts with dietary phosphate restriction, dialysis, and the use of phosphate binders. The efficacy of phosphate binders may be inherently limited because the mechanism of action does not target any phosphate absorption pathway. Thus, therapeutic innovations are needed to address the limitations of phosphate binders. Novel therapies leveraging new mechanistic understandings of phosphate absorption and the primacy of the paracellular pathway may improve phosphate control. Phosphate absorption inhibitors that target the pathway are a novel therapeutic class. Tenapanor is an investigational first-in-class nonbinder phosphate absorption inhibitor that inhibits the sodium-hydrogen exchanger isoform 3 to reduce paracellular permeability specific to phosphate. Phosphate absorption inhibitors may represent a new mechanistic approach to phosphate management with the potential to improve clinical outcomes.
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Affiliation(s)
- Steven N. Fishbane
- Department of Medicine, Zucker School of Medicine at Hofstra, Hempstead, Great Neck, NY
- Northwell, Great Neck, NY
| | - Sagar Nigwekar
- Department of Medicine, Harvard Medical School, Boston, MA
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Inaba M, Une Y, Ikejiri K, Kanda H, Fukagawa M, Akizawa T. Dose-Response of Tenapanor in Patients With Hyperphosphatemia Undergoing Hemodialysis in Japan—a Phase 2 Randomized Trial. Kidney Int Rep 2021; 7:177-188. [PMID: 35155857 PMCID: PMC8820999 DOI: 10.1016/j.ekir.2021.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 11/03/2021] [Accepted: 11/08/2021] [Indexed: 12/18/2022] Open
Abstract
Introduction Simplified, but effective, hyperphosphatemia treatments with novel mechanisms of action, tolerable safety profiles, and low pill burden are needed for patients undergoing hemodialysis. Tenapanor is a calcium (Ca)-free, nonmetal, nonpolymeric drug that reduces phosphate absorption by selectively inhibiting intestinal sodium-hydrogen exchanger 3. As the serum phosphorus (P) level-lowering effect of tenapanor has not been evaluated in Japanese patients with hyperphosphatemia undergoing hemodialysis, we evaluated its efficacy and safety in this population. Methods This was a multicenter, phase 2, double-blind, placebo-controlled, parallel-group, dose-finding study. Change in serum P level from baseline at week 6 was the primary end point. Results Overall, 207 patients were randomized to 5 groups (placebo [n = 41] and tenapanor 5-mg taken twice daily [BID] [n = 42], 10-mg BID [n = 41], 30-mg BID [n = 42], and 30-mg BID dose-titration [n = 41]) and treated for 6 weeks. Mean changes from baseline at week 6 in serum P level were 0.64, −0.93, −1.36, −1.92, and −1.99 mg/dl in the placebo and tenapanor groups, respectively. Serum P level was significantly decreased from baseline in all tenapanor groups compared with placebo (P < 0.001, for each dose). Diarrhea was the most frequent drug-related adverse event (AE) with an incidence of 9.8%, 50.0%, 65.9%, 76.2%, and 65.9% in the respective placebo and tenapanor groups. Conclusion In Japanese patients undergoing hemodialysis, tenapanor was found to have a dose-responsive, serum P level-lowering effect. Diarrhea was the most frequent drug-related AE; most cases were mild and generally tolerable. Tenapanor may become a first-in-class therapeutic agent for patients with hyperphosphatemia.
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Block GA, Bleyer AJ, Silva AL, Weiner DE, Lynn RI, Yang Y, Rosenbaum DP, Chertow GM. Safety and Efficacy of Tenapanor for Long-term Serum Phosphate Control in Maintenance Dialysis: A 52-Week Randomized Phase 3 Trial (PHREEDOM). KIDNEY360 2021; 2:1600-1610. [PMID: 35372979 PMCID: PMC8785778 DOI: 10.34067/kid.0002002021] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 08/25/2021] [Indexed: 12/17/2022]
Abstract
Background Treating hyperphosphatemia is a tenet of dialysis care. This trial assessed the safety and efficacy of tenapanor for the management of hyperphosphatemia. Methods In this 52-week phase 3 study (NCT03427125), participants receiving maintenance dialysis with both hyperphosphatemia (serum phosphate 6.0-10.0 mg/dl) and a 1.5 mg/dl increase after phosphate binder washout were randomized (3:1) to tenapanor 30 mg twice daily for 26 weeks (randomized treatment period) or sevelamer carbonate (52-week safety control). Participants completing 26 weeks of treatment with tenapanor were rerandomized (1:1) to tenapanor or placebo for 12 weeks (randomized withdrawal period), and were eligible to enter the 14-week safety extension period. With input from the US Food and Drug Administration, the primary efficacy end point was the difference in the change in serum phosphate from the end of the randomized treatment period to the end of the randomized withdrawal period, among participants who achieved ≥1.2 mg/dl decrease in serum phosphate during the randomized treatment period (efficacy analysis set). Efficacy was also evaluated in the intention-to-treat (ITT) analysis set. Results Of 564 eligible participants randomized to receive tenapanor (n=423) or sevelamer carbonate (n=141) during the randomized treatment period, 255 (60%) in the tenapanor group subsequently were rerandomized to tenapanor (n=128) or placebo (n=127) during the randomized withdrawal period. In the efficacy analysis set (n=131), the difference in estimated mean change in serum phosphate level between tenapanor and placebo from the beginning to the end of the randomized withdrawal period was -1.4 mg/dl (P<0.0001); in the ITT analysis set (n=243), the estimated mean difference was -0.7 mg/dl (P=0.002). Loosened stools were the most frequently reported adverse event (53% during the randomized treatment period). Serious adverse events were reported more frequently for participants treated with sevelamer carbonate (16%-23% across the three study periods) compared with tenapanor (11%-17%). Conclusions Tenapanor reduced serum phosphate concentrations and maintained control of serum phosphate in participants receiving maintenance dialysis, with an acceptable safety and tolerability profile.
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Affiliation(s)
- Geoffrey A Block
- Clinical Research and Medical Affairs, US Renal Care, Inc., Plano, Texas
| | - Anthony J Bleyer
- Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Arnold L Silva
- Boise Kidney and Hypertension Institute, Meridian, Idaho
| | - Daniel E Weiner
- Division of Nephrology, Tufts Medical Center, Boston, Massachusetts
| | - Robert I Lynn
- Department of Medicine, Albert Einstein College of Medicine, New York, New York.,Kidney Medical Associates, New York, New York
| | - Yang Yang
- Biometrics, Ardelyx, Inc., Fremont, California
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Irsik DL, Bollag WB, Isales CM. Renal Contributions to Age-Related Changes in Mineral Metabolism. JBMR Plus 2021; 5:e10517. [PMID: 34693188 PMCID: PMC8520061 DOI: 10.1002/jbm4.10517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/28/2021] [Accepted: 05/09/2021] [Indexed: 11/10/2022] Open
Abstract
Aging results in a general decline in function in most systems. This is particularly true with respect to the skeleton and renal systems, impacting mineral homeostasis. Calcium and phosphate regulation requires tight coordination among the intestine, bone, parathyroid gland, and kidney. The role of the intestine is to absorb calcium and phosphate from the diet. The bone stores or releases calcium and phosphate depending on the body's needs. In response to low plasma ionized calcium concentration, the parathyroid gland produces parathyroid hormone, which modulates bone turnover. The kidney reabsorbs or excretes the minerals and serves as the final regulator of plasma concentration. Many hormones are involved in this process in addition to parathyroid hormone, including fibroblast growth factor 23 produced by the bone and calcitriol synthesized by the kidney. Sclerostin, calcitonin, osteoprotegerin, and receptor activator of nuclear factor‐κB ligand also contribute to tissue‐specific regulation. Changes in the function of organs due to aging or disease can perturb this balance. During aging, the intestine cannot absorb calcium efficiently due to decreased expression of key proteins. In the bone, the balance between bone formation and bone resorption tends toward the latter in older individuals. The kidney may not filter blood as efficiently in the later decades of life, and the expression of certain proteins necessary for mineral homeostasis declines with age. These changes often lead to dysregulation of organismal mineral homeostasis. This review will focus on how mineral homeostasis is impacted by aging with a particular emphasis on the kidney's role in this process. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Debra L Irsik
- Charlie Norwood VA Medical Center Augusta GA USA.,Department of Neuroscience and Regenerative Medicine Augusta University Augusta GA USA
| | - Wendy B Bollag
- Charlie Norwood VA Medical Center Augusta GA USA.,Department of Physiology Augusta University Augusta GA USA
| | - Carlos M Isales
- Department of Neuroscience and Regenerative Medicine Augusta University Augusta GA USA.,Division of Endocrinology, Department of Medicine Augusta University Augusta GA USA
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