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Thomas L, Dissanayake LV, Tahmasbi M, Staruschenko A, Al-Masri S, Dominguez Rieg JA, Rieg T. Vitamin D 3 suppresses Npt2c abundance and differentially modulates phosphate and calcium homeostasis in Npt2a knockout mice. Sci Rep 2024; 14:16997. [PMID: 39043847 PMCID: PMC11266651 DOI: 10.1038/s41598-024-67839-4] [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: 03/09/2024] [Accepted: 07/16/2024] [Indexed: 07/25/2024] Open
Abstract
Vitamin D3 is clinically used for the treatment of vitamin D3 deficiency or osteoporosis, partially because of its role in regulating phosphate (Pi) and calcium (Ca2+) homeostasis. The renal sodium-phosphate cotransporter 2a (Npt2a) plays an important role in Pi homeostasis; however, the role of vitamin D3 in hypophosphatemia has never been investigated. We administered vehicle or vitamin D3 to wild-type (WT) mice or hypophosphatemic Npt2a-/- mice. In contrast to WT mice, vitamin D3 treatment increased plasma Pi levels in Npt2a-/- mice, despite similar levels of reduced parathyroid hormone and increased fibroblast growth factor 23. Plasma Ca2+ was increased ~ twofold in both genotypes. Whereas WT mice were able to increase urinary Pi and Ca2+/creatinine ratios, in Npt2a-/- mice, Pi/creatinine was unchanged and Ca2+/creatinine drastically decreased, coinciding with the highest kidney Ca2+ content, highest plasma creatinine, and greatest amount of nephrocalcinosis. In Npt2a-/- mice, vitamin D3 treatment completely diminished Npt2c abundance, so that mice resembled Npt2a/c double knockout mice. Abundance of intestinal Npt2b and claudin-3 (tight junctions protein) were reduced in Npt2a-/- only, the latter might facilitate the increase in plasma Pi in Npt2a-/- mice. Npt2a might function as regulator between renal Ca2+ excretion and reabsorption in response to vitamin D3.
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Affiliation(s)
- Linto Thomas
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
- James A. Haley Veterans' Hospital, Tampa, FL, USA
| | - Lashodya V Dissanayake
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Maryam Tahmasbi
- Department of Pathology and Cell Biology, University of South Florida, Tampa, FL, USA
| | - Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
- James A. Haley Veterans' Hospital, Tampa, FL, USA
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, USA
| | - Sima Al-Masri
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Jessica A Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
- James A. Haley Veterans' Hospital, Tampa, FL, USA
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, USA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
- James A. Haley Veterans' Hospital, Tampa, FL, USA.
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, USA.
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Dominguez Rieg JA, Rieg T. New functions and roles of the Na +-H +-exchanger NHE3. Pflugers Arch 2024; 476:505-516. [PMID: 38448727 DOI: 10.1007/s00424-024-02938-9] [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: 02/05/2024] [Revised: 02/22/2024] [Accepted: 02/27/2024] [Indexed: 03/08/2024]
Abstract
The sodium/proton exchanger isoform 3 (NHE3) is expressed in the intestine and the kidney, where it contributes to hydrogen secretion and sodium (re)absorption. The roles of this transporter have been studied by the use of the respective knockout mice and by using pharmacological inhibitors. Whole-body NHE3 knockout mice suffer from a high mortality rate (with only ∼30% of mice surviving into adulthood), and based on the expression of NHE3 in both intestine and kidney, some conclusions that were originally derived were based on this rather complex phenotype. In the last decade, more refined models have been developed that added temporal and spatial control of NHE3 expression. For example, novel mouse models have been developed with a knockout of NHE3 in intestinal epithelial cells, tubule/collecting duct of the kidney, proximal tubule of the kidney, and thick ascending limb of the kidney. These refined models have significantly contributed to our understanding of the role of NHE3 in a tissue/cell type-specific manner. In addition, tenapanor was developed, which is a non-absorbable, intestine-specific NHE3 inhibitor. In rat and human studies, tenapanor lowered intestinal Pi uptake and was effective in lowering plasma Pi levels in patients on hemodialysis. Of note, diarrhea is seen as a side effect of tenapanor (with its indication for the treatment of constipation) and in intestine-specific NHE3 knockout mice; however, effects on plasma Pi were not supported by this mouse model which showed enhanced and not reduced intestinal Pi uptake. Further studies indicated that the gut microbiome in mice lacking intestinal NHE3 resembles an intestinal environment favoring the competitive advantage of inflammophilic over anti-inflammatory species, something similar seen in patients with inflammatory bowel disease. This review will highlight recent developments and summarize newly gained insight from these refined models.
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Affiliation(s)
- Jessica A Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
- James A. Haley Veterans' Hospital, Tampa, FL, 33612, USA
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, 33602, USA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA.
- James A. Haley Veterans' Hospital, Tampa, FL, 33612, USA.
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, 33602, USA.
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Licata G, Tancredi V, Gambardella A, Megna M, Fabbrocini G, Raimondo A, Lembo S, Ligrone L, Cusano F, Argenziano G. Efficacy, tolerability and patient's satisfaction for the treatment of moderate to severe plaque psoriasis with apremilast in the real-life setting of Campania region, Italy. Ital J Dermatol Venerol 2023; 158:452-456. [PMID: 37721774 DOI: 10.23736/s2784-8671.23.07638-7] [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: 09/19/2023]
Abstract
BACKGROUND Little information is available from real-life studies evaluating the efficacy of apremilast in moderate-to-severe psoriasis. METHODS In this real-life study, we retrospectively examined a database of 231 patients with moderate-to-severe psoriasis treated with apremilast (30 mg twice/day) and followed up for 52 weeks. Disease severity and treatment response were assessed by the Psoriasis Area and Severity Index (PASI) at baseline and after 16, 24, and 52 weeks. Quality of life was assessed by the Dermatology Life Quality Index (DLQI). RESULTS PASI score decreased from 14.6 at baseline to 4.1 and 1.2 at 16 and 24 weeks. At 24 weeks, 86.7% of patients achieved a PASI score of ≤3 and this improved up to 52 weeks, where all patients had a PASI score of ≤3. At 24 weeks, PASI 75, 90 and 100 responses were achieved in 92%, 83.2% and 36.3% of patients, respectively. At 52 weeks, PASI 75, 90 and 100 response were achieved in 97%, 89.3% and 62% of patients, respectively. DLQI score was 12.4 at baseline and decreased to 2 at week 24, and close to 0 at week 52. No serious adverse event was reported during the treatment with apremilast. CONCLUSIONS In patients with moderate-severe chronic psoriasis in a real world-setting apremilast was shown to be effective and safe up to 52 weeks.
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Affiliation(s)
| | - Vittorio Tancredi
- Dermatology Unit, Department of Mental and Physical Health and Preventive Medicine, Luigi Vanvitelli University of Campania, Naples, Italy
| | - Alessio Gambardella
- Dermatology Unit, Department of Mental and Physical Health and Preventive Medicine, Luigi Vanvitelli University of Campania, Naples, Italy
| | - Matteo Megna
- Dermatology Unit, Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Gabriella Fabbrocini
- Dermatology Unit, Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Annunziata Raimondo
- Department of Medicine, Surgery and Dentistry, Scuola Medica Salernitana, University of Salerno, Baronissi, Salerno, Italy
| | - Serena Lembo
- Department of Medicine, Surgery and Dentistry, Scuola Medica Salernitana, University of Salerno, Baronissi, Salerno, Italy
| | - Luigi Ligrone
- Dermatology Unit, San Giovanni di Dio e Ruggi D'Aragona University Hospital, Scuola Medica Salernitana, University of Salerno, Salerno, Italy
| | - Francesco Cusano
- Unit of Dermatology, San Pio Hospital - G. Rummo Hospital, Benevento, Italy
| | - Giuseppe Argenziano
- Dermatology Unit, Department of Mental and Physical Health and Preventive Medicine, Luigi Vanvitelli University of Campania, Naples, Italy
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Xue J, Thomas L, Dominguez Rieg JA, Fenton RA, Rieg T. NHE3 in the thick ascending limb is required for sustained but not acute furosemide-induced urinary acidification. Am J Physiol Renal Physiol 2022; 323:F141-F155. [PMID: 35635321 PMCID: PMC9306792 DOI: 10.1152/ajprenal.00013.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Na+/H+ exchanger isoform 3 (NHE3) facilitates Na+ reabsorption and H+ secretion by the kidneys. Despite stronger NHE3 abundance in the thick ascending limb (TAL) compared to the S1 and S2 segments of the proximal tubule, the role of NHE3 in the TAL is poorly understood. To investigate the role of NHE3 in the TAL, we generated and phenotyped TAL-specific NHE3 knockout mice (NHE3TAL-KO). Compared to control mice, NHE3TAL-KO mice did not show significant differences in body weight, blood pH or plasma Na+, K+ or Cl- levels. Fluid intake trended to be higher and urine osmolality was significantly lower in NHE3TAL-KO mice. Despite a similar GFR, NHE3TAL-KO mice had a greater urinary K+/creatinine ratio. One proposed role of NHE3 relates to furosemide-induced urinary acidification. Acute bolus treatment with furosemide under anesthesia did not result in differences in the dose dependence of urinary flow rate, Cl- excretion or maximal urinary acidification between genotypes; however, in contrast to control mice, urinary pH returned immediately towards baseline levels in NHE3TAL-KO mice. Chronic furosemide treatment reduced urine osmolality similarly in both genotypes but metabolic alkalosis, hypokalemia and calciuresis were absent in NHE3TAL-KO mice. Compared to vehicle, chronic furosemide treatment in control mice resulted in greater NKCC2 and lower Npt2a abundances, effects that were absent in NHE3TAL-KO mice. In summary, NHE3 in the TAL plays a role for the sustained acidification effect of furosemide. Consistent with this, long-term treatment with furosemide did not result in metabolic alkalosis in NHE3TAL-KO mice.
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Affiliation(s)
- Jianxiang Xue
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Linto Thomas
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Jessica A Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States.,James A. Haley Veterans' Hospital, Tampa, Florida, United States
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States.,James A. Haley Veterans' Hospital, Tampa, Florida, United States.,Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, United States
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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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Ostrom KF, LaVigne JE, Brust TF, Seifert R, Dessauer CW, Watts VJ, Ostrom RS. Physiological Roles of Mammalian Transmembrane Adenylyl Cyclase Isoforms. Physiol Rev 2021; 102:815-857. [PMID: 34698552 DOI: 10.1152/physrev.00013.2021] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Adenylyl cyclases (ACs) catalyze the conversion of ATP to the ubiquitous second messenger cAMP. Mammals possess nine isoforms of transmembrane ACs, dubbed AC1-9, that serve as major effector enzymes of G protein-coupled receptors. The transmembrane ACs display varying expression patterns across tissues, giving potential for them having a wide array of physiologic roles. Cells express multiple AC isoforms, implying that ACs have redundant functions. Furthermore, all transmembrane ACs are activated by Gαs so it was long assumed that all ACs are activated by Gαs-coupled GPCRs. AC isoforms partition to different microdomains of the plasma membrane and form prearranged signaling complexes with specific GPCRs that contribute to cAMP signaling compartments. This compartmentation allows for a diversity of cellular and physiological responses by enabling unique signaling events to be triggered by different pools of cAMP. Isoform specific pharmacological activators or inhibitors are lacking for most ACs, making knockdown and overexpression the primary tools for examining the physiological roles of a given isoform. Much progress has been made in understanding the physiological effects mediated through individual transmembrane ACs. GPCR-AC-cAMP signaling pathways play significant roles in regulating functions of every cell and tissue, so understanding each AC isoform's role holds potential for uncovering new approaches for treating a vast array of pathophysiological conditions.
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Affiliation(s)
- Katrina F Ostrom
- W. M. Keck Science Department, Claremont McKenna College, Claremont, CA, United States
| | - Justin E LaVigne
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States
| | - Tarsis F Brust
- Department of Pharmaceutical Sciences, Palm Beach Atlantic University, West Palm Beach, FL, United States
| | - Roland Seifert
- Institute of Pharmacology, Hannover Medical School, Hannover, Germany
| | - Carmen W Dessauer
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas, United States
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States.,Purdue Institute for Drug Discovery, Purdue University, West Lafayette, IN, United States.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, United States
| | - Rennolds S Ostrom
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, United States
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An inducible intestinal epithelial cell-specific NHE3 knockout mouse model mimicking congenital sodium diarrhea. Clin Sci (Lond) 2020; 134:941-953. [PMID: 32227118 PMCID: PMC8819665 DOI: 10.1042/cs20200065] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/25/2020] [Accepted: 03/27/2020] [Indexed: 12/13/2022]
Abstract
The sodium–hydrogen exchanger isoform 3 (NHE3, SLC9A3) is abundantly expressed in the gastrointestinal tract and is proposed to play essential roles in Na+ and fluid absorption as well as acid–base homeostasis. Mutations in the SLC9A3 gene can cause congenital sodium diarrhea (CSD). However, understanding the precise role of intestinal NHE3 has been severely hampered due to the lack of a suitable animal model. To navigate this problem and better understand the role of intestinal NHE3, we generated a tamoxifen-inducible intestinal epithelial cell-specific NHE3 knockout mouse model (NHE3IEC-KO). Before tamoxifen administration, the phenotype and blood parameters of NHE3IEC-KO were unremarkable compared with control mice. After tamoxifen administration, NHE3IEC-KO mice have undetectable levels of NHE3 in the intestine. NHE3IEC-KO mice develop watery, alkaline diarrhea in combination with a swollen small intestine, cecum and colon. The persistent diarrhea results in higher fluid intake. After 3 weeks, NHE3IEC-KO mice show a ~25% mortality rate. The contribution of intestinal NHE3 to acid–base and Na+ homeostasis under normal conditions becomes evident in NHE3IEC-KO mice that have metabolic acidosis, lower blood bicarbonate levels, hyponatremia and hyperkalemia associated with drastically elevated plasma aldosterone levels. These results demonstrate that intestinal NHE3 has a significant contribution to acid–base, Na+ and volume homeostasis, and lack of intestinal NHE3 has consequences on intestinal structural integrity. This mouse model mimics and explains the phenotype of individuals with CSD carrying SLC9A3 mutations.
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Kaunitz JD. Oral Defense: How Oral Rehydration Solutions Revolutionized the Treatment of Toxigenic Diarrhea. Dig Dis Sci 2020; 65:345-348. [PMID: 31900719 PMCID: PMC7193728 DOI: 10.1007/s10620-019-06023-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jonathan D. Kaunitz
- Medical Service, West Los Angeles VAMC and Departments of Medicine and Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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9
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Barrett KE. A New Target to Treat Diarrhea in Cholera? J Infect Dis 2019; 220:1711-1712. [PMID: 30624702 DOI: 10.1093/infdis/jiz014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 01/07/2019] [Indexed: 11/13/2022] Open
Affiliation(s)
- Kim E Barrett
- Department of Medicine, University of California, San Diego School of Medicine, La Jolla
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Thomas L, Xue J, Murali SK, Fenton RA, Dominguez Rieg JA, Rieg T. Pharmacological Npt2a Inhibition Causes Phosphaturia and Reduces Plasma Phosphate in Mice with Normal and Reduced Kidney Function. J Am Soc Nephrol 2019; 30:2128-2139. [PMID: 31409727 DOI: 10.1681/asn.2018121250] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 07/14/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The kidneys play an important role in phosphate homeostasis. Patients with CKD develop hyperphosphatemia in the later stages of the disease. Currently, treatment options are limited to dietary phosphate restriction and oral phosphate binders. The sodium-phosphate cotransporter Npt2a, which mediates a large proportion of phosphate reabsorption in the kidney, might be a good therapeutic target for new medications for hyperphosphatemia. METHODS The authors assessed the effects of the first orally bioavailable Npt2a inhibitor (Npt2a-I) PF-06869206 in normal mice and mice that had undergone subtotal nephrectomy (5/6 Nx), a mouse model of CKD. Dose-response relationships of sodium, chloride, potassium, phosphate, and calcium excretion were assessed in response to the Npt2a inhibitor in both groups of mice. Expression and localization of Npt2a/c and levels of plasma phosphate, calcium, parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF-23) were studied up to 24-hours after Npt2a-I treatment. RESULTS In normal mice, Npt2a inhibition caused a dose-dependent increase in urinary phosphate (ED50 approximately 21 mg/kg), calcium, sodium and chloride excretion. In contrast, urinary potassium excretion, flow rate and urinary pH were not affected dose dependently. Plasma phosphate and PTH significantly decreased after 3 hours, with both returning to near baseline levels after 24 hours. Similar effects were observed in the mouse model of CKD but were reduced in magnitude. CONCLUSIONS Npt2a inhibition causes a dose-dependent increase in phosphate, sodium and chloride excretion associated with reductions in plasma phosphate and PTH levels in normal mice and in a CKD mouse model.
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Affiliation(s)
- Linto Thomas
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida; and
| | - Jianxiang Xue
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida; and
| | | | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Jessica A Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida; and
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida; and
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