1
|
Billing AM, Kim YC, Gullaksen S, Schrage B, Raabe J, Hutzfeldt A, Demir F, Kovalenko E, Lassé M, Dugourd A, Fallegger R, Klampe B, Jaegers J, Li Q, Kravtsova O, Crespo-Masip M, Palermo A, Fenton RA, Hoxha E, Blankenberg S, Kirchhof P, Huber TB, Laugesen E, Zeller T, Chrysopoulou M, Saez-Rodriguez J, Magnussen C, Eschenhagen T, Staruschenko A, Siuzdak G, Poulsen PL, Schwab C, Cuello F, Vallon V, Rinschen MM. Metabolic Communication by SGLT2 Inhibition. Circulation 2024; 149:860-884. [PMID: 38152989 PMCID: PMC10922673 DOI: 10.1161/circulationaha.123.065517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 11/22/2023] [Indexed: 12/29/2023]
Abstract
BACKGROUND SGLT2 (sodium-glucose cotransporter 2) inhibitors (SGLT2i) can protect the kidneys and heart, but the underlying mechanism remains poorly understood. METHODS To gain insights on primary effects of SGLT2i that are not confounded by pathophysiologic processes or are secondary to improvement by SGLT2i, we performed an in-depth proteomics, phosphoproteomics, and metabolomics analysis by integrating signatures from multiple metabolic organs and body fluids after 1 week of SGLT2i treatment of nondiabetic as well as diabetic mice with early and uncomplicated hyperglycemia. RESULTS Kidneys of nondiabetic mice reacted most strongly to SGLT2i in terms of proteomic reconfiguration, including evidence for less early proximal tubule glucotoxicity and a broad downregulation of the apical uptake transport machinery (including sodium, glucose, urate, purine bases, and amino acids), supported by mouse and human SGLT2 interactome studies. SGLT2i affected heart and liver signaling, but more reactive organs included the white adipose tissue, showing more lipolysis, and, particularly, the gut microbiome, with a lower relative abundance of bacteria taxa capable of fermenting phenylalanine and tryptophan to cardiovascular uremic toxins, resulting in lower plasma levels of these compounds (including p-cresol sulfate). SGLT2i was detectable in murine stool samples and its addition to human stool microbiota fermentation recapitulated some murine microbiome findings, suggesting direct inhibition of fermentation of aromatic amino acids and tryptophan. In mice lacking SGLT2 and in patients with decompensated heart failure or diabetes, the SGLT2i likewise reduced circulating p-cresol sulfate, and p-cresol impaired contractility and rhythm in human induced pluripotent stem cell-derived engineered heart tissue. CONCLUSIONS SGLT2i reduced microbiome formation of uremic toxins such as p-cresol sulfate and thereby their body exposure and need for renal detoxification, which, combined with direct kidney effects of SGLT2i, including less proximal tubule glucotoxicity and a broad downregulation of apical transporters (including sodium, amino acid, and urate uptake), provides a metabolic foundation for kidney and cardiovascular protection.
Collapse
Affiliation(s)
- Anja M. Billing
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Young Chul Kim
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla (Y.C.K., M.C.-M., V.V.)
- VA San Diego Healthcare System, CA (Y.C.K., M.C.-M., V.V.)
| | - Søren Gullaksen
- Clinical Medicine (S.G., P.L.P.), Aarhus University, Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark (S.G., E.L.)
| | - Benedikt Schrage
- Department of Cardiology, University Heart and Vascular Center Hamburg, Germany (B.S., S.B., P.K., T.Z., C.M.)
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
| | - Janice Raabe
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (J.R., B.K., T.E., F.C.)
| | - Arvid Hutzfeldt
- III Department of Medicine and Hamburg Center for Kidney Health, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.H., M.L., E.H., T.B.H., M.M.R.)
| | - Fatih Demir
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Elina Kovalenko
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Moritz Lassé
- III Department of Medicine and Hamburg Center for Kidney Health, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.H., M.L., E.H., T.B.H., M.M.R.)
| | - Aurelien Dugourd
- Heidelberg University, Faculty of Medicine, and Heidelberg University Hospital, Institute for Computational Biomedicine, BioQuant, Heidelberg, Germany (A.D., R.F., J.S.-R.)
| | - Robin Fallegger
- Heidelberg University, Faculty of Medicine, and Heidelberg University Hospital, Institute for Computational Biomedicine, BioQuant, Heidelberg, Germany (A.D., R.F., J.S.-R.)
| | - Birgit Klampe
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (J.R., B.K., T.E., F.C.)
| | - Johannes Jaegers
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Qing Li
- Engineering (Q.L., C.S.), Aarhus University, Denmark
| | - Olha Kravtsova
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Maria Crespo-Masip
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla (Y.C.K., M.C.-M., V.V.)
- VA San Diego Healthcare System, CA (Y.C.K., M.C.-M., V.V.)
| | - Amelia Palermo
- Scripps Research, Center for Metabolomics, San Diego, CA (A.P., G.S., M.M.R.)
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles (A.P.)
| | - Robert A. Fenton
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Elion Hoxha
- III Department of Medicine and Hamburg Center for Kidney Health, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.H., M.L., E.H., T.B.H., M.M.R.)
| | - Stefan Blankenberg
- Department of Cardiology, University Heart and Vascular Center Hamburg, Germany (B.S., S.B., P.K., T.Z., C.M.)
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
| | - Paulus Kirchhof
- Department of Cardiology, University Heart and Vascular Center Hamburg, Germany (B.S., S.B., P.K., T.Z., C.M.)
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
- Institute of Cardiovascular Sciences, University of Birmingham, United Kingdom (P.K.)
| | - Tobias B. Huber
- III Department of Medicine and Hamburg Center for Kidney Health, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.H., M.L., E.H., T.B.H., M.M.R.)
| | - Esben Laugesen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark (S.G., E.L.)
- Diagnostic Centre, Silkeborg Regional Hospital, Denmark (E.L.)
| | - Tanja Zeller
- Department of Cardiology, University Heart and Vascular Center Hamburg, Germany (B.S., S.B., P.K., T.Z., C.M.)
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
| | - Maria Chrysopoulou
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
| | - Julio Saez-Rodriguez
- Heidelberg University, Faculty of Medicine, and Heidelberg University Hospital, Institute for Computational Biomedicine, BioQuant, Heidelberg, Germany (A.D., R.F., J.S.-R.)
| | - Christina Magnussen
- Department of Cardiology, University Heart and Vascular Center Hamburg, Germany (B.S., S.B., P.K., T.Z., C.M.)
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
| | - Thomas Eschenhagen
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (J.R., B.K., T.E., F.C.)
| | - Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa (O.K., A.S.)
| | - Gary Siuzdak
- Scripps Research, Center for Metabolomics, San Diego, CA (A.P., G.S., M.M.R.)
| | - Per L. Poulsen
- Clinical Medicine (S.G., P.L.P.), Aarhus University, Denmark
- Steno Diabetes Center (P.L.P.), Aarhus University, Denmark
| | | | - Friederike Cuello
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany (B.S., J.R., S.B., P.K., T.Z., C.M., T.E., F.C.)
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (J.R., B.K., T.E., F.C.)
| | - Volker Vallon
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla (Y.C.K., M.C.-M., V.V.)
- VA San Diego Healthcare System, CA (Y.C.K., M.C.-M., V.V.)
| | - Markus M. Rinschen
- Departments of Biomedicine (A.M.B., F.D., E.K., J.J., R.A.F., M.C., M.M.R.), Aarhus University, Denmark
- Aarhus Institute of Advanced Studies (M.M.R.), Aarhus University, Denmark
- III Department of Medicine and Hamburg Center for Kidney Health, University Medical Center Hamburg-Eppendorf, Hamburg, Germany (A.H., M.L., E.H., T.B.H., M.M.R.)
- Scripps Research, Center for Metabolomics, San Diego, CA (A.P., G.S., M.M.R.)
| |
Collapse
|
2
|
Vallon V. How can inhibition of glucose and sodium transport in the early proximal tubule protect the cardiorenal system? Nephrol Dial Transplant 2024:gfae060. [PMID: 38439675 DOI: 10.1093/ndt/gfae060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2024] Open
Abstract
What mechanisms can link the inhibition of SGLT2-mediated Na+-coupled glucose reabsorption in early proximal tubules to kidney and heart protection in patients with and without type 2 diabetes? Due to physical and functional coupling of SGLT2 to other sodium and metabolite transporters in the early proximal tubule (including NHE3, URAT1), inhibitors of SGLT2 (SGLT2i) reduce reabsorption not only of glucose, inducing osmotic diuresis, but of other metabolites plus of a larger amount of sodium than expected based on SGLT2 inhibition alone, thereby reducing volume retention, hypertension, and hyperuricemia. Metabolic adaptations to SGLT2i include a fasting-like response, with enhanced lipolysis and formation of ketone bodies that serve as additional fuel for kidneys and heart. Making use of the physiology of tubulo-glomerular communication, SGLT2i functionally lower glomerular capillary pressure and filtration rate, thereby reducing physical stress on the glomerular filtration barrier, tubular exposure to albumin and nephrotoxic compounds, and the oxygen demand for reabsorbing the filtered load. Together with reduced gluco-toxicity in the early proximal tubule and better distribution of transport work along the nephron, SGLT2i can preserve tubular integrity and transport function and, thereby, GFR in the long-term. By shifting transport downstream, SGLT2 inhibitors may simulate systemic hypoxia at the oxygen sensors in the deep cortex/outer medulla, which stimulates erythropoiesis and, together with osmotic diuresis, enhances hematocrit and thereby improves oxygen delivery to all organs. The described SGLT2-dependent effects may be complemented by off-target effects of SGLT2i on the heart itself and on the microbiome formation of cardiovascular-effective uremic toxins.
Collapse
Affiliation(s)
- Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Pharmacology, University of California San Diego, La Jolla, CA, USA
- VA San Diego Healthcare System, San Diego, CA, USA
| |
Collapse
|
3
|
Oe Y, Kim YC, Sidorenko VS, Zhang H, Kanoo S, Lopez N, Goodluck HA, Crespo-Masip M, Vallon V. SGLT2 inhibitor dapagliflozin protects the kidney in a murine model of Balkan nephropathy. Am J Physiol Renal Physiol 2024; 326:F227-F240. [PMID: 38031729 DOI: 10.1152/ajprenal.00228.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 11/06/2023] [Accepted: 11/27/2023] [Indexed: 12/01/2023] Open
Abstract
Proximal tubular uptake of aristolochic acid (AA) forms aristolactam (AL)-DNA adducts, which cause a p53/p21-mediated DNA damage response and acute tubular injury. Recurrent AA exposure causes kidney function loss and fibrosis in humans (Balkan endemic nephropathy) and mice and is a model of (acute kidney injury) AKI to chronic kidney disease (CKD) transition. Inhibitors of the proximal tubule sodium-glucose transporter SGLT2 can protect against CKD progression, but their effect on AA-induced kidney injury remains unknown. C57BL/6J mice (15-wk-old) were administered vehicle or AA every 3 days for 3 wk (10 and 3 mg/kg ip in females and males, respectively). Dapagliflozin (dapa, 0.01 g/kg diet) or vehicle was initiated 7 days prior to AA injections. All dapa effects were sex independent, including a robust glycosuria. Dapa lowered urinary kidney-injury molecule 1 (KIM-1) and albumin (both normalized to creatinine) after the last AA injection and kidney mRNA expression of early DNA damage response markers (p53 and p21) 3 wk later at the study end. Dapa also attenuated AA-induced increases in plasma creatinine as well as AA-induced up-regulation of renal pro-senescence, pro-inflammatory and pro-fibrotic genes, and kidney collagen staining. When assessed 1 day after a single AA injection, dapa pretreatment attenuated AL-DNA adduct formation by 10 and 20% in kidney and liver, respectively, associated with reduced p21 expression. Initiating dapa application after the last AA injection also improved kidney outcome but in a less robust manner. In conclusion, the first evidence is presented that pretreatment with an SGLT2 inhibitor can attenuate the AA-induced DNA damage response and subsequent nephropathy.NEW & NOTEWORTHY Recurrent exposure to aristolochic acid (AA) causes kidney function loss and fibrosis in mice and in humans, e.g., in the form of the endemic Balkan nephropathy. Inhibitors of the proximal tubule sodium-glucose transporter SGLT2 can protect against CKD progression, but their effect on AA-induced kidney injury remains unknown. Here we provide the first evidence in a murine model that pretreatment with an SGLT2 inhibitor can attenuate the AA-induced DNA damage response and subsequent nephropathy.
Collapse
Affiliation(s)
- Yuji Oe
- Department of Medicine, University of California-San Diego, La Jolla, California, United States
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States
| | - Young Chul Kim
- Department of Medicine, University of California-San Diego, La Jolla, California, United States
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States
| | - Viktoriya S Sidorenko
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, United States
| | - Haiyan Zhang
- Department of Pathology, University of California-San Diego, San Diego, California, United States
| | - Sadhana Kanoo
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States
| | - Natalia Lopez
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States
| | - Helen A Goodluck
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States
| | - Maria Crespo-Masip
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States
| | - Volker Vallon
- Department of Medicine, University of California-San Diego, La Jolla, California, United States
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States
| |
Collapse
|
4
|
Kanoo S, Goodluck H, Kim YC, Garrido AN, Crespo-Masip M, Lopez N, Zhang H, Gonzalez-Villalobos RA, Ma LJ, Vallon V. Deletion, but not heterozygosity, of eNOS raises blood pressure and aggravates nephropathy in BTBR ob/ob mice. Nephron Clin Pract 2024:000536522. [PMID: 38301618 DOI: 10.1159/000536522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 01/20/2024] [Indexed: 02/03/2024] Open
Abstract
INTRODUCTION ob/ob mice are a leptin-deficient type 2 diabetes mellitus model, which, on a BTBR background, mimics glomerular pathophysiology of diabetic nephropathy (DN). Since leptin deficiency reduces blood pressure (BP), and endothelial nitric oxide synthase (eNOS) lowers BP and is kidney protective, we attempted to develop a more robust DN model by introducing eNOS deficiency in BTBR ob/ob mice. METHODS Six experimental groups included littermate male and female BTBR ob/ob or wild-type for ob (control) as well as wild-type (WT), heterozygote (HET) or knockout (KO) for eNOS. Systolic BP (by automated tail-cuff) and GFR (by FITC sinistrin plasma kinetics) were determined in awake mice at 27-30 weeks of age followed by molecular and histological kidney analyses. RESULTS Male and female ob/ob WT presented hyperglycemia and larger body and kidney weight, GFR, glomerular injury, and urine albumin to creatinine ratio (UACR) despite modestly lower BP vs control WT. These effects were associated with higher tubular injury score and renal mRNA expression of NGAL only in males, whereas female ob/ob WT unexpectedly had lower KIM-1 and COL1A1 expression vs control WT, indicating sex differences. HET for eNOS did not consistently alter BP or renal outcome in control or ob/ob. In comparison, eNOS KO increased BP (15-25 mmHg) and worsened renal markers of injury, inflammation and fibrosis, GFR, UACR, and survival rates, as observed in control and, more pronounced, in ob/ob mice and independent of sex. CONCLUSIONS Deletion, but not heterozygosity, of eNOS raises blood pressure and aggravates nephropathy in BTBR ob/ob mice.
Collapse
|
5
|
Numata S, Oishee MJ, McDermott J, Koepsell H, Vallon V, Blanco G. Deletion of the Sodium Glucose Cotransporter 1 (Sglt-1) impairs mouse sperm movement. Mol Reprod Dev 2024; 91:e23723. [PMID: 38282316 DOI: 10.1002/mrd.23723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 10/25/2023] [Accepted: 12/06/2023] [Indexed: 01/30/2024]
Abstract
The Sodium Glucose Cotransporter Isoform 1 (Sglt-1) is a symporter that moves Na+ and glucose into the cell. While most studies have focused on the role of Sglt-1 in the small intestine and kidney, little is known about this transporter's expression and function in other tissues. We have previously shown that Sglt-1 is expressed in the mouse sperm flagellum and that its inhibition interferes with sperm metabolism and function. Here, we further investigated the importance of Sglt-1 in sperm, using a Sglt-1 knockout mouse (Sglt-1 KO). RNA, immunocytochemistry, and glucose uptake analysis confirmed the ablation of Sglt-1 in sperm. Sglt-1 KO male mice are fertile and exhibit normal sperm counts and morphology. However, Sglt-1 null sperm displayed a significant reduction in total, progressive and other parameters of sperm motility compared to wild type (WT) sperm. The reduction in motility was exacerbated when sperm were challenged to swim in media with higher viscosity. Parameters of capacitation, namely protein tyrosine phosphorylation and acrosomal reaction, were similar in Sglt-1 KO and WT sperm. However, Sglt-1 KO sperm displayed a significant decrease in hyperactivation. The impaired motility of Sglt-1 null sperm was observed in media containing glucose as the only energy substrate. Interestingly, the addition of pyruvate and lactate to the media partially recovered sperm motility of Sglt-1 KO sperm, both in the low and high viscosity media. Altogether, these results support an important role for Sglt-1 in sperm energetics and function, providing sperm with a higher capacity for glucose uptake.
Collapse
Affiliation(s)
- September Numata
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Mumtarin Jannat Oishee
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Jeffrey McDermott
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Hermann Koepsell
- Institute for Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Volker Vallon
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla, California, USA
| | - Gustavo Blanco
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA
| |
Collapse
|
6
|
Layton AT, Vallon V. Did you know how SGLT2 inhibitors protect the kidney? Acta Physiol (Oxf) 2023; 238:e14011. [PMID: 37288493 DOI: 10.1111/apha.14011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 05/22/2023] [Accepted: 05/24/2023] [Indexed: 06/09/2023]
Affiliation(s)
- Anita T Layton
- Departments of Applied Mathematics and Biology, University of Waterloo, Waterloo, Ontario, Canada
- Cheriton School of Computer Science, School of Pharmacy, University of Waterloo, Waterloo, Ontario, Canada
| | - Volker Vallon
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, California, USA
- San Diego Veterans Affairs Healthcare System, San Diego, California, USA
| |
Collapse
|
7
|
Oe Y, Vallon V. CRRT 2023 Meeting: Targeting Amino Acid Transport to Improve Acute Kidney Injury Outcome. Nephron Clin Pract 2023; 147:774-777. [PMID: 37490876 PMCID: PMC10808280 DOI: 10.1159/000531918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 06/07/2023] [Indexed: 07/27/2023] Open
Abstract
BACKGROUND In acute kidney injury (AKI), proximal tubules are a primary site of injury, resulting in significant alterations in amino acid transport and metabolism. However, little is known about the therapeutic potential of targeting amino acid transporters. Here, we briefly review the first experimental evidence that targeting the sodium-coupled amino acid transporter SLC6A19 (B0AT1) can improve AKI outcome. SUMMARY SLC6A19 is expressed in the small intestine and early proximal tubules, where it absorbs and reabsorbs most of the ingested and filtered neutral amino acids, respectively. Systemic SLC6A19 deficiency alleviates renal cellular senescence and suppresses subsequent inflammation and fibrosis in a murine model of aristolochic acid-induced nephropathy, which targets the proximal tubule. The underlying mechanisms remain to be determined, but potentially may include reduced tubular workload, an inhibitory effect on SGLT2, downstream shift in transport and preconditioning of late proximal tubules, and induction of a fasting-like phenotype and lowering tubular accumulation of branched-chain amino acids, which all can promote tubular health.
Collapse
Affiliation(s)
- Yuji Oe
- Department of Medicine, University of California San Diego, La Jolla, CA
- Veterans Affairs San Diego Healthcare System, San Diego, CA
| | - Volker Vallon
- Department of Medicine, University of California San Diego, La Jolla, CA
- Veterans Affairs San Diego Healthcare System, San Diego, CA
| |
Collapse
|
8
|
Kim YC, Fattah H, Fu Y, Nespoux J, Vallon V. Expression of leptin receptor in renal tubules is sparse but implicated in leptin-dependent kidney gene expression and function. Am J Physiol Renal Physiol 2023; 324:F544-F557. [PMID: 37102688 PMCID: PMC10228677 DOI: 10.1152/ajprenal.00279.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 03/30/2023] [Accepted: 04/16/2023] [Indexed: 04/28/2023] Open
Abstract
Leptin regulates energy balance via leptin receptors expressed in central and peripheral tissues, but little is known about leptin-sensitive kidney genes and the role of the tubular leptin receptor (Lepr) in response to a high-fat diet (HFD). Quantitative RT-PCR analysis of Lepr splice variants A, B, and C revealed a ratio of ∼100:10:1 in the mouse kidney cortex and medulla, with medullary levels being ∼10 times higher. Leptin replacement in ob/ob mice for 6 days reduced hyperphagia, hyperglycemia, and albuminuria, associated with normalization of kidney mRNA expression of molecular markers of glycolysis, gluconeogenesis, amino acid synthesis, and megalin. Normalization of leptin for 7 h in ob/ob mice did not normalize hyperglycemia or albuminuria. Tubular knockdown of Lepr [Pax8-Lepr knockout (KO)] and in situ hybridization revealed a minor fraction of Lepr mRNA in tubular cells compared with endothelial cells. Nevertheless, Pax8-Lepr KO mice had lower kidney weight. Moreover, while HFD-induced hyperleptinemia, increases in kidney weight and glomerular filtration rate, and a modest blood pressure lowering effect were similar compared with controls, they showed a blunted rise in albuminuria. Use of Pax8-Lepr KO and leptin replacement in ob/ob mice identified acetoacetyl-CoA synthetase and gremlin 1 as tubular Lepr-sensitive genes that are increased and reduced by leptin, respectively. In conclusion, leptin deficiency may increase albuminuria via systemic metabolic effects that impinge on kidney megalin expression, whereas hyperleptinemia may induce albuminuria by direct tubular Lepr effects. Implications of Lepr variants and the novel tubular Lepr/acetoacetyl-CoA synthetase/gremlin 1 axis remain to be determined.NEW & NOTEWORTHY This study provides new insights into kidney gene expression of leptin receptor splice variants, leptin-sensitive kidney gene expression, and the role of the leptin receptor in renal tubular cells for the response to diet-induced hyperleptinemia and obesity including albuminuria.
Collapse
Affiliation(s)
- Young Chul Kim
- Division of Nephrology and Hypertension, Department of Medicine, University of California-San Diego, La Jolla, California, United States
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States
| | - Hadi Fattah
- Division of Nephrology and Hypertension, Department of Medicine, University of California-San Diego, La Jolla, California, United States
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States
| | - Yiling Fu
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States
| | - Josselin Nespoux
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States
| | - Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California-San Diego, La Jolla, California, United States
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States
- Department of Pharmacology, University of California-San Diego, La Jolla, California, United States
| |
Collapse
|
9
|
Patel R, Fu Y, Khang S, Benardeau AM, Thomson SC, Vallon V. Responses in Blood Pressure and Kidney Function to Soluble Guanylyl Cyclase Stimulation or Activation in Normal and Diabetic Rats. Nephron Clin Pract 2022; 147:281-300. [PMID: 36265461 PMCID: PMC10115913 DOI: 10.1159/000526934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 08/22/2022] [Indexed: 01/09/2023] Open
Abstract
Introduction: Agonists of soluble guanylate cyclase (sGC) are being developed as treatment for cardiovascular disease. Most effects of nitric oxide (NO) on glomerular and tubular function are mediated through sGC but whether sGC agonists mimic these effects is unknown. Methods: Renal clearance and micropuncture studies were performed in Wistar-Froemter rats (WF), with or without streptozotocin diabetes (STZ-WF), and in Goto-Kakizaki rats (GK) with mild type-2 diabetes to test for acute effects of the sGC “stimulator” BAY 41-2272, which synergizes with endogenous NO, and the “activator” runcaciguat, which generates cGMP independent of NO. Results: Both sGC agonists reduced arterial blood pressure (MAP). For MAP reductions <10% the drugs increased GFR in WF and STZ-WF but not in GK. Larger MAP reductions outweighed this effect and GFR declined, with better preserved GFR in STZ-WF. Changes in GFR could not be accounted for by changes in RBF, suggesting parallel changes in ultrafiltration pressure and/or ultrafiltration coefficient. The doses chosen for micropuncture in WF and GK reduced MAP by 2–10% and the net effect on single nephron GFR and ultrafiltration pressure was neutral. Effects of the drugs on tubular reabsorption were dominated by declining MAP and no natriuretic effect observed at any dose. Discussion/Conclusion: sGC agonists impact kidney function directly and because they reduce MAP. The direct tendency to increase GFR is most apparent for MAP reductions <10%. The direct effect is otherwise subtle and overridden when MAP declines more. Effects of sGC agonists on tubular reabsorption are dominated by effects on MAP.
Collapse
Affiliation(s)
- Rohit Patel
- Department of Medicine, University of California San Diego, La Jolla, USA & VA San Diego Healthcare System, San Diego, USA
| | - Yiling Fu
- Department of Medicine, University of California San Diego, La Jolla, USA & VA San Diego Healthcare System, San Diego, USA
| | - Ser Khang
- Department of Medicine, University of California San Diego, La Jolla, USA & VA San Diego Healthcare System, San Diego, USA
| | | | - Scott C. Thomson
- Department of Medicine, University of California San Diego, La Jolla, USA & VA San Diego Healthcare System, San Diego, USA
| | - Volker Vallon
- Department of Medicine, University of California San Diego, La Jolla, USA & VA San Diego Healthcare System, San Diego, USA
- Department of Pharmacology, University of California San Diego, La Jolla, USA
| |
Collapse
|
10
|
Navarro Garrido A, Kim YC, Oe Y, Zhang H, Crespo-Masip M, Goodluck HA, Kanoo S, Sanders PW, Bröer S, Vallon V. Aristolochic acid-induced nephropathy is attenuated in mice lacking the neutral amino acid transporter B 0AT1 ( Slc6a19). Am J Physiol Renal Physiol 2022; 323:F455-F467. [PMID: 35979966 PMCID: PMC9484999 DOI: 10.1152/ajprenal.00181.2022] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/29/2022] [Accepted: 08/10/2022] [Indexed: 01/10/2023] Open
Abstract
B0AT1 (Slc6a19) mediates absorption of neutral amino acids in the small intestine and in the kidneys, where it is primarily expressed in early proximal tubules (S1-S2). To determine the role of B0AT1 in nephropathy induced by aristolochic acid (AA), which targets the proximal tubule, littermate female B0AT1-deficient (Slc6a19-/-), heterozygous (Slc6a19+/-), and wild-type (WT) mice were administered AA (10 mg/kg ip) or vehicle every 3 days for 3 wk, and analyses were performed after the last injection or 3 wk later. Vehicle-treated mice lacking Slc6a19 showed normal body and kidney weight and plasma creatinine versus WT mice. The urinary glucose-to-creatinine ratio (UGCR) and urinary albumin-to-creatinine ratio (UACR) were two to four times higher in vehicle-treated Slc6a19-/- versus WT mice, associated with lesser expression of early proximal transporters Na+-glucose cotransporter 2 and megalin, respectively. AA caused tubular injury independently of B0AT1, including robust increases in cortical mRNA expression of p53, p21, and hepatitis A virus cellular receptor 1 (Havcr1), downregulation of related proximal tubule amino acid transporters B0AT2 (Slc6a15), B0AT3 (Slc6a18), and Slc7a9, and modest histological tubular damage and a rise in plasma creatinine. Absence of B0AT1, however, attenuated AA-induced cortical upregulation of mRNA markers of senescence (p16), inflammation [lipocalin 2 (Lcn2), C-C motif chemokine ligand 2 (Ccl2), and C-C motif chemokine receptor 2 (Ccr2)], and fibrosis [tissue inhibitor of metallopeptidase 1 (Timp1), transforming growth factor-β1 (Tgfb1), and collagen type I-α1 (Col1a1)], associated with lesser fibrosis staining, lesser suppression of proximal tubular organic anion transporter 1, restoration of Na+-glucose cotransporter 2 expression, and prevention of the AA-induced fivefold increase in the urinary albumin-to-creatinine ratio observed in WT mice. The data suggest that proximal tubular B0AT1 is important for the physiology of renal glucose and albumin retention but potentially deleterious for the kidney response following AA-induced kidney injury.NEW & NOTEWORTHY Based on insights from studies manipulating glucose transport, the hypothesis has been proposed that inhibiting intestinal uptake or renal reabsorption of energy substrates has unique therapeutic potential to improve metabolic disease and kidney outcome in response to injury. The present study takes this idea to B0AT1, the major transporter for neutral amino acids in the intestine and kidney, and shows that its absence attenuates aristolochic acid-induced nephropathy.
Collapse
Affiliation(s)
- Aleix Navarro Garrido
- Department of Medicine, University of California-San Diego, La Jolla, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Young Chul Kim
- Department of Medicine, University of California-San Diego, La Jolla, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Yuji Oe
- Department of Medicine, University of California-San Diego, La Jolla, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Haiyan Zhang
- Department of Pathology, University of California-San Diego, San Diego, California
| | - Maria Crespo-Masip
- Department of Medicine, University of California-San Diego, La Jolla, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Helen A Goodluck
- Department of Medicine, University of California-San Diego, La Jolla, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Sadhana Kanoo
- Department of Medicine, University of California-San Diego, La Jolla, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Paul W Sanders
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
- Department of Veterans Affairs Medical Center, Birmingham, Alabama
| | - Stefan Bröer
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Volker Vallon
- Department of Medicine, University of California-San Diego, La Jolla, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| |
Collapse
|
11
|
Abstract
SGLT2 inhibitors can protect the kidneys of patients with and without type 2 diabetes from failing. This includes blood glucose dependent and independent mechanisms. SGLT2 inhibitors lower glomerular pressure and filtration, thereby reducing the physical stress on the filtration barrier and the oxygen demand for tubular reabsorption. This improves cortical oxygenation, which, together with lesser tubular glucotoxicity and improved mitochondrial function and autophagy, can reduce proinflammatory and profibrotic signaling and preserve tubular function and GFR in long term. By shifting transport downstream, SGLT2 inhibitors may mimic systemic hypoxia and stimulate erythropoiesis, which improves oxygen delivery to the kidney and other organs.
Collapse
Affiliation(s)
- Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA, USA; Department of Pharmacology, University of California San Diego, La Jolla, CA, USA; VA San Diego Healthcare System, 3350 La Jolla Village Drive (9151), San Diego, CA 92161, USA.
| |
Collapse
|
12
|
Masuda T, Ohara K, Vallon V, Nagata D. SGLT2 inhibitor and loop diuretic induce different vasopressin and fluid homeostatic responses in nondiabetic rats. Am J Physiol Renal Physiol 2022; 323:F361-F369. [PMID: 35900341 PMCID: PMC9423725 DOI: 10.1152/ajprenal.00070.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/20/2022] [Accepted: 07/20/2022] [Indexed: 12/12/2022] Open
Abstract
Loop diuretics are commonly used diuretics in the treatment of fluid retention but induce hypovolemia-related renal dysfunction. Na+-glucose cotransporter 2 (SGLT2) inhibitors induce osmotic diuresis, but body fluid volume is maintained by stimulating vasopressin-induced fluid intake and collecting duct water reabsorption as previously reported in diabetic rats. We aimed to test the hypothesis that unlike SGLT2 inhibitors, loop diuretics lack activation of similar fluid homeostatic mechanisms. Nondiabetic male Sprague-Dawley rats were treated daily by oral gavage with vehicle, the SGLT2 inhibitor ipragliflozin (5 mg/kg), or the loop diuretic furosemide (50 mg/kg) and monitored in metabolic cages for 2 or 7 days. Ipragliflozin and furosemide similarly increased urine volume on day 2. This was associated with increased serum Na+ concentration, urine vasopressin excretion, fluid intake, and solute-free water reabsorption in response to ipragliflozin but not to furosemide. Ipragliflozin maintained fluid balance (fluid intake - urine volume) on day 2 and total body water measured by bioimpedance spectroscopy and serum creatinine on day 7. In comparison, furosemide decreased fluid balance on day 2 and decreased total body water and increased serum creatinine on day 7. Furosemide, but not ipragliflozin, increased plasma renin activity, and systolic blood pressure was similar among the groups. In conclusion, the osmotic diuresis of the SGLT2 inhibitor increased serum Na+ concentration and the vasopressin-related stimulation of fluid intake and renal water retention maintained fluid balance, whereas the loop diuretic did not engage the compensatory vasopressin system. The data suggest differences in vasopressin and fluid homeostatic responses between SGLT2 inhibitors and loop diuretics.NEW & NOTEWORTHY In nondiabetic rats, the Na+-glucose cotransporter 2 (SGLT2) inhibitor ipragliflozin increased vasopressin-related stimulation of fluid intake and free water reabsorption and maintained fluid balance and serum creatinine, whereas the loop diuretic furosemide reduced vasopressin and induced a negative fluid balance followed by a subsequent increase in serum creatinine. This study suggests that differences in vasopressin secretion in response to a SGLT2 inhibitor or loop diuretic may contribute to differences in body fluid status and subsequent renal function.
Collapse
Affiliation(s)
- Takahiro Masuda
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Ken Ohara
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Volker Vallon
- Division of Nephrology and Hypertension, Departments of Medicine and Pharmacology, University of California-San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Daisuke Nagata
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Japan
| |
Collapse
|
13
|
Zhang J, Cai J, Cui Y, Jiang S, Wei J, Kim YC, Chan J, Thalakola A, Le T, Xu L, Wang L, Jiang K, Wang X, Wang H, Cheng F, Buggs J, Koepsell H, Vallon V, Liu R. Corrigendum to Zhang J, Cai J, Cui Y, Jiang S, Wei J, Kim YC, Chan J, Thalakola A, Le T, Xu L, Wang L, Jiang K, Wang X, Wang H, Cheng F, Buggs J, Koepsell H, Vallon V, Liu R. "Role of the macula densa sodium glucose cotransporter type 1-neuronal nitric oxide synthase-tubuloglomerular feedback pathway in diabetic hyperfiltration." Kidney Int. 2022;101:541-550. Kidney Int 2022; 102:448. [PMID: 35870819 DOI: 10.1016/j.kint.2022.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Jie Zhang
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Jing Cai
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, Jinan, Shandong, China
| | - Yu Cui
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Shan Jiang
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Jin Wei
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Young Chul Kim
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Jenna Chan
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Anish Thalakola
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Thanh Le
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Lan Xu
- College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Lei Wang
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Kun Jiang
- Department of Anatomic Pathology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, USA
| | - Ximing Wang
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Haibo Wang
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, Jinan, Shandong, China
| | - Feng Cheng
- Department of Pharmaceutical Science, College of Pharmacy, University of South Florida, Tampa, Florida, USA
| | - Jacentha Buggs
- Advanced Organ Disease & Transplantation Institute, Tampa General Hospital, Tampa, Florida, USA
| | - Hermann Koepsell
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Ruisheng Liu
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
| |
Collapse
|
14
|
Vallon V, Kim YC. Protecting the Kidney: The Unexpected Logic of Inhibiting a Glucose Transporter. Clin Pharmacol Ther 2022; 112:434-438. [PMID: 35689828 DOI: 10.1002/cpt.2651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 05/13/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, California, USA.,Department of Pharmacology, University of California San Diego, La Jolla, California, USA.,VA San Diego Healthcare System, San Diego, California, USA
| | - Young Chul Kim
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, California, USA.,VA San Diego Healthcare System, San Diego, California, USA
| |
Collapse
|
15
|
Sharma S, Katz R, Ginsberg C, Bullen A, Vallon V, Thomson S, Moe OW, Hoofnagle AN, de Leeuw PW, Kroon AA, Houben AJHM, Ix JH. Renal Clearance of Fibroblast Growth Factor-23 (FGF23) and its Fragments in Humans. J Bone Miner Res 2022; 37:1170-1178. [PMID: 35373859 PMCID: PMC9177785 DOI: 10.1002/jbmr.4553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 03/08/2022] [Accepted: 03/28/2022] [Indexed: 11/06/2022]
Abstract
Relative abundance of fibroblast growth factor-23 (FGF23) measured by the C-terminal (cFGF23, which measures both intact FGF23 and C-terminal fragments) versus intact (iFGF23, measures only intact hormone) assays varies by kidney function in humans. Differential kidney clearance may explain this finding. We measured cFGF23 and iFGF23 in the aorta and bilateral renal veins of 162 patients with essential hypertension undergoing renal angiography. Using multivariable linear regression, we examined factors associated with aorta to renal vein reduction of FGF23 using both assays. Similar parameters and with addition of urine concentrations of cFGF23 and iFGF23 were measured in six Wistar rats. Mean ± standard deviation (SD) age was 54 ± 12 years, 54% were women, and mean creatinine clearance was 72 ± 48 mL/min/100 g. The human kidney reduced the concentrations of both cFGF23 (16% ± 12%) and iFGF23 (21% ± 16%), but reduction was higher for iFGF23. Greater kidney creatinine and PTH reductions were each independently associated with greater reductions of both cFGF23 and iFGF23. The greater kidney reduction of iFGF23 compared to cFGF23 appeared stable and consistent across the range of creatinine clearance evaluated. Kidney clearance was similar, and urine concentrations of both assays were low in the rat models, suggesting kidney metabolism of both cFGF23 and iFGF23. Renal reduction of iFGF23 is higher than that of creatinine and cFGF23. Our data suggest that FGF23 is metabolized by the kidney. However, the major cell types involved in metabolization of FGF23 requires future study. Kidney clearance of FGF23 does not explain differences in C-terminal and intact moieties across the range of kidney function. © 2022 American Society for Bone and Mineral Research (ASBMR).
Collapse
Affiliation(s)
- Shilpa Sharma
- Division of Nephrology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Nephrology Section, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Ronit Katz
- University of Washington, Seattle, WA, USA
| | - Charles Ginsberg
- Division of Nephrology-Hypertension, Department of Medicine, University of California San Diego, San Diego, CA, USA
| | - Alexander Bullen
- Division of Nephrology-Hypertension, Department of Medicine, University of California San Diego, San Diego, CA, USA.,Nephrology Section, Veterans Affairs San Diego Healthcare System, La Jolla, CA, USA
| | - Volker Vallon
- Division of Nephrology-Hypertension, Department of Medicine, University of California San Diego, San Diego, CA, USA.,Nephrology Section, Veterans Affairs San Diego Healthcare System, La Jolla, CA, USA.,Department of Pharmacology, University of California-San Diego, La Jolla, CA, USA
| | - Scott Thomson
- Division of Nephrology-Hypertension, Department of Medicine, University of California San Diego, San Diego, CA, USA.,Nephrology Section, Veterans Affairs San Diego Healthcare System, La Jolla, CA, USA.,Department of Pharmacology, University of California-San Diego, La Jolla, CA, USA
| | - Orson W Moe
- Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Departments of Internal Medicine and Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Peter W de Leeuw
- Department of Internal Medicine and CARIM School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Abraham A Kroon
- Department of Internal Medicine and CARIM School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Alfons J H M Houben
- Department of Internal Medicine and CARIM School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Joachim H Ix
- Division of Nephrology-Hypertension, Department of Medicine, University of California San Diego, San Diego, CA, USA.,Nephrology Section, Veterans Affairs San Diego Healthcare System, La Jolla, CA, USA
| |
Collapse
|
16
|
Abstract
SGLT2 inhibitors can protect the kidneys of patients with and without type 2 diabetes mellitus and slow the progression towards end-stage kidney disease. Blocking tubular SGLT2 and spilling glucose into the urine, which triggers a metabolic counter-regulation similar to fasting, provides unique benefits, not only as an anti-hyperglycemic strategy. These include a low hypoglycemia risk and a shift from carbohydrate to lipid utilization and mild ketogenesis, thereby reducing body weight and providing an additional energy source. SGLT2 inhibitors counteract hyperreabsorption in the early proximal tubule, which acutely lowers glomerular pressure and filtration and thereby reduces the physical stress on the filtration barrier, the filtration of tubule-toxic compounds, and the oxygen demand for tubular reabsorption. This improves cortical oxygenation, which, together with lesser tubular gluco-toxicity and improved mitochondrial function and autophagy, can reduce pro-inflammatory, pro-senescence, and pro-fibrotic signaling and preserve tubular function and GFR in the long-term. By shifting transport downstream, SGLT2 inhibitors more equally distribute the transport burden along the nephron and may mimic systemic hypoxia to stimulate erythropoiesis, which improves oxygen delivery to the kidney and other organs. SGLT1 inhibition improves glucose homeostasis by delaying intestinal glucose absorption and by increasing the release of gastrointestinal incretins. Combined SGLT1 and SGLT2 inhibition has additive effects on renal glucose excretion and blood glucose control. SGLT1 in the macula densa senses luminal glucose, which affects glomerular hemodynamics and has implications for blood pressure control. More studies are needed to better define the therapeutic potential of SGLT1 inhibition to protect the kidney, alone or in combination with SGLT2 inhibition.
Collapse
Affiliation(s)
- Yuji Oe
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA 92161, USA
- VA San Diego Healthcare System, San Diego, CA 92161, USA
| | - Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA 92161, USA
- VA San Diego Healthcare System, San Diego, CA 92161, USA
- Department of Pharmacology, University of California San Diego, La Jolla, CA 92161, USA
| |
Collapse
|
17
|
Billing A, Kim Y, Vallon V, Rinschen M. Systemic proteomic and metabolomic signature of the SGLT2 inhibitor dapagliflozin. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r4450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
18
|
Alam SM, Gierden KJ, Zhao T, Lu SS, Dixit M, Babicheva A, Yuan J, Vallon V, Zemljic‐Harpf AE. Sustained Exposure to the SGLT2 Inhibitor Ertugliflozin, But Not NHE‐1 Inhibition By Cariporide, Attenuates Adrenergic Stimulation of Cytosolic CA
2+
Levels in Spontaneously Contracting Cardiac Myocytes. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r2252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sifat M. Alam
- AnesthesiologyVA San Diego Healthcare System, and University of California, San Diego, Dep. of AnesthesiologySan DiegoCA
| | - Kyle J. Gierden
- AnesthesiologyVA San Diego Healthcare System, and University of California, San Diego, Dep. of AnesthesiologySan DiegoCA
| | - Tengteng Zhao
- MedicineUniversity of California, San Diego, Dep. of Medicine, Div. of Pulmonary, Critical Care, and Sleep MedicineSan DiegoCA
| | - Sun S. Lu
- AnesthesiologyVA San Diego Healthcare System, and University of California, San Diego, Dep. of AnesthesiologySan DiegoCA
| | - Mihir Dixit
- AnesthesiologyVA San Diego Healthcare System, and University of California, San Diego, Dep. of AnesthesiologySan DiegoCA
| | - Aleksandra Babicheva
- PulmonologyUniversity of California, San Diego, Dep. of Medicine, Div. of Pulmonary, Critical Care, and Sleep MedicineSan DiegoCA
| | - Jason Yuan
- PulmonologyUniversity of California, San Diego, Dep. of Medicine, Div. of Pulmonary, Critical Care, and Sleep MedicineSan DiegoCA
| | - Volker Vallon
- Medicine, Div. NephrologyVA San Diego Healthcare System, and University of California, San Diego, Dep. of Medicine, Div. of NephrologySan DiegoCA
| | - Alice E. Zemljic‐Harpf
- AnesthesiologyVA San Diego Healthcare System, and University of California, San Diego, Dep. of AnesthesiologySan DiegoCA
| |
Collapse
|
19
|
Suijk D, van Baar M, van Bommel E, Iqbal Z, Krebber M, Vallon V, Touw D, Hoorn E, Nieuwdorp M, Kramer M, Joles J, Bjornstad P, van Raalte D. SGLT2 Inhibition and Uric Acid Excretion in Patients with Type 2 Diabetes and Normal Kidney Function. Clin J Am Soc Nephrol 2022; 17:663-671. [PMID: 35322793 PMCID: PMC9269569 DOI: 10.2215/cjn.11480821] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 03/17/2022] [Indexed: 11/23/2022]
Abstract
Background and objectives: Sodium glucose transporter 2 (SGLT2)-inhibitor-induced uric acid lowering may contribute to kidney protective effects of the drug-class in people with type 2 diabetes. This study investigates mechanisms of plasma uric acid lowering by SGLT2-inhibitors in people with type 2 diabetes with a focus on urate transporter (URAT)1. Methods: We conducted an analysis of two randomized, clinical trials. First, in the Renoprotective Effects of Dapagliflozin in Type 2 Diabetes (RED) study, 44 people with type 2 diabetes were randomized to dapagliflozin or gliclazide for 12 weeks. Plasma uric acid, fractional uric acid excretion and hemodynamic kidney function were measured in the fasted state and during clamped eu- or hyperglycemia. Second, in the Uric Acid Excretion study (UREX) study, 10 people with type 2 diabetes received 1-week empagliflozin, benzbromarone and their combination in a cross-over design and effects on plasma uric acid, fractional uric acid excretion and 24-hr uric acid excretion were measured. Results: In the RED study, compared to the fasted state (5.3±1.1mg/dL), acute hyperinsulinemia and hyperglycemia significantly reduced plasma uric acid by 0.2±0.3 and 0.4±0.3 mg/dL (both p<0.001), while increasing fractional uric acid excretion (by 3.2±3.1% and 8.9±4.5% respectively (both p<0.001). Dapagliflozin reduced plasma uric acid by 0.8±0.8mg/dL, 1.0±1.0mg/dL and by 0.8±0.7mg/dL during fasting, hyperinsulinemic-euglycemic and hyperglycemic conditions (p<0.001), whereas fractional uric acid excretion in 24-hr urine increased by 3.0±2.1% (p<0.001) and 2.6±4.5% during hyperinsulinemic-euglycemic conditions (p=0.003). Fractional uric acid excretion strongly correlated to fractional glucose excretion (r= 0.35, p=0.02). In the UREX study, empagliflozin and benzbromarone both significantly reduced plasma uric acid and increased fractional uric acid excretion. Effects of combination therapy did not differ from benzbromarone monotherapy. Conclusion: In conclusion, SGLT2-inhibitors induce uric acid excretion, which is strongly linked to urinary glucose excretion and which is attenuated during concomitant pharmacological blockade of URAT1.
Collapse
Affiliation(s)
- Danii Suijk
- D Suijk, Diabetes Center, Department of Internal Medicine, Amsterdam University Medical Centres, Duivendrecht, Netherlands
| | - Michaël van Baar
- M van Baar, Diabetes Center, Department of Internal Medicine, Amsterdam University Medical Centres, Duivendrecht, Netherlands
| | - Erik van Bommel
- E van Bommel, Diabetes Center, Department of Internal Medicine, Amsterdam University Medical Centres, Duivendrecht, Netherlands
| | - Zainab Iqbal
- Z Iqbal, Diabetes Center, Department of Internal Medicine, Amsterdam University Medical Centres, Duivendrecht, Netherlands
| | - Merle Krebber
- M Krebber, Department of Nephrology and Hypertension, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Volker Vallon
- V Vallon, Division of Nephrology and hypertension, Department of Medicine, University of California San Diego, La Jolla, United States
| | - Daan Touw
- D Touw, Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, Groningen, Netherlands
| | - Ewout Hoorn
- E Hoorn, Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, Netherlands
| | - Max Nieuwdorp
- M Nieuwdorp, Diabetes Center, Department of Internal Medicine, Amsterdam University Medical Centres, Duivendrecht, Netherlands
| | - Mark Kramer
- M Kramer, Diabetes Center, Department of Internal Medicine, Amsterdam University Medical Centres, Duivendrecht, Netherlands
| | - Jaap Joles
- J Joles, Department of Nephrology and Hypertension, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Petter Bjornstad
- P Bjornstad, Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado Denver School of Medicine, Aurora, United States
| | - Daniël van Raalte
- D van Raalte, Diabetes Center, Department of Internal Medicine, Amsterdam University Medical Centres, Duivendrecht, Netherlands
| |
Collapse
|
20
|
Zhang J, Cai J, Cui Y, Jiang S, Wei J, Kim YC, Chan J, Thalakola A, Le T, Xu L, Wang L, Jiang K, Wang X, Wang H, Cheng F, Buggs J, Koepsell H, Vallon V, Liu R. Role of the macula densa sodium glucose cotransporter type 1-neuronal nitric oxide synthase-tubuloglomerular feedback pathway in diabetic hyperfiltration. Kidney Int 2022; 101:541-550. [PMID: 34843754 PMCID: PMC8863629 DOI: 10.1016/j.kint.2021.10.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 10/09/2021] [Accepted: 10/26/2021] [Indexed: 02/08/2023]
Abstract
An increase of glomerular filtration rate (GFR) is a common observation in early diabetes and is considered a key risk factor for subsequent kidney injury. However, the mechanisms underlying diabetic hyperfiltration have not been fully clarified. Here, we tested the hypothesis that macula densa neuronal nitric oxide synthase (NOS1) is upregulated via sodium glucose cotransporter type 1 (SGLT1) in diabetes, which then inhibits tubuloglomerular feedback (TGF) promoting glomerular hyperfiltration. Therefore, we examined changes in cortical NOS1 expression and phosphorylation, nitric oxide production in the macula densa, TGF response, and GFR during the early stage of insulin-deficient (Akita) diabetes in wild-type and macula densa-specific NOS1 knockout mice. A set of sophisticated techniques including microperfusion of juxtaglomerular apparatus in vitro, micropuncture of kidney tubules in vivo, and clearance kinetics of plasma fluorescent-sinistrin were employed. Complementary studies tested the role of SGLT1 in SGLT1 knockout mice and explored NOS1 expression and phosphorylation in kidney biopsies of cadaveric donors. Diabetic mice had upregulated macula densa NOS1, inhibited TGF and elevated GFR. Macula densa-selective NOS1 knockout attenuated the diabetes-induced TGF inhibition and GFR elevation. Additionally, deletion of SGLT1 prevented the upregulation of macula densa NOS1 and attenuated inhibition of TGF in diabetic mice. Furthermore, the expression and phosphorylation levels of NOS1 were increased in cadaveric kidneys of diabetics and positively correlated with blood glucose as well as estimated GFR in the donors. Thus, our findings demonstrate that the macula densa SGLT1-NOS1-TGF pathway plays a crucial role in the control of GFR in diabetes.
Collapse
Affiliation(s)
- Jie Zhang
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA.
| | - Jing Cai
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, FL, Department of Otolarynggology-Head and Neck Surgery, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yu Cui
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, FL
| | - Shan Jiang
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, FL
| | - Jin Wei
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, FL
| | - Young Chul Kim
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA
| | - Jenna Chan
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, FL
| | - Anish Thalakola
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, FL
| | - Thanh Le
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, FL
| | - Lan Xu
- College of Public Health, University of South Florida, Tampa, FL
| | - Lei Wang
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, FL
| | - Kun Jiang
- Department of Anatomic Pathology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL
| | - Ximing Wang
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, FL
| | - Haibo Wang
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, FL, Department of Otolarynggology-Head and Neck Surgery, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Feng Cheng
- Department of Pharmaceutical Science, College of Pharmacy, University of South Florida, Tampa, FL
| | - Jacentha Buggs
- Advanced Organ Disease & Transplantation Institute, Tampa General Hospital, Tampa, FL
| | - Hermann Koepsell
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA
| | - Ruisheng Liu
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, FL
| |
Collapse
|
21
|
Abstract
The proximal tubule of the kidney is programmed to reabsorb all filtered glucose and fructose. Glucose is taken up by apical sodium-glucose cotransporters SGLT2 and SGLT1 whereas SGLT5 and potentially SGLT4 and GLUT5 have been implicated in apical fructose uptake. The glucose taken up by the proximal tubule is typically not metabolized but leaves via the basolateral facilitative glucose transporter GLUT2 and is returned to the systemic circulation or used as an energy source by distal tubular segments after basolateral uptake via GLUT1. The proximal tubule generates new glucose in metabolic acidosis and the postabsorptive phase, and fructose serves as an important substrate. In fact, under physiological conditions and intake, fructose taken up by proximal tubules is primarily utilized for gluconeogenesis. In the diabetic kidney, glucose is retained and gluconeogenesis enhanced, the latter in part driven by fructose. This is maladaptive as it sustains hyperglycemia. Moreover, renal glucose retention is coupled to sodium retention through SGLT2 and SGLT1, which induces secondary deleterious effects. SGLT2 inhibitors are new anti-hyperglycemic drugs that can protect the kidneys and heart from failing independent of kidney function and diabetes. Dietary excess of fructose also induces tubular injury. This can be magnified by kidney formation of fructose under pathological conditions. Fructose metabolism is linked to urate formation, which partially accounts for fructose-induced tubular injury, inflammation, and hemodynamic alterations. Fructose metabolism favors glycolysis over mitochondrial respiration as urate suppresses aconitase in the tricarboxylic acid cycle, and has been linked to potentially detrimental aerobic glycolysis (Warburg effect). © 2022 American Physiological Society. Compr Physiol 12:2995-3044, 2022.
Collapse
Affiliation(s)
- Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, California, USA,Department of Pharmacology, University of California San Diego, La Jolla, California, USA,VA San Diego Healthcare System, San Diego, California, USA,Correspondence to and
| | - Takahiko Nakagawa
- Division of Nephrology, Rakuwakai-Otowa Hospital, Kyoto, Japan,Correspondence to and
| |
Collapse
|
22
|
Zhang J, Wang X, Cui Y, Jiang S, Wei J, Chan J, Thalakola A, Le T, Xu L, Zhao L, Wang L, Jiang K, Cheng F, Patel T, Buggs J, Vallon V, Liu R. Knockout of Macula Densa Neuronal Nitric Oxide Synthase Increases Blood Pressure in db/db Mice. Hypertension 2021; 78:1760-1770. [PMID: 34657443 DOI: 10.1161/hypertensionaha.121.17643] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
[Figure: see text].
Collapse
Affiliation(s)
- Jie Zhang
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Ximing Wang
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa.,Department of Radiology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China (X.W.)
| | - Yu Cui
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China (Y.C., L.Z.)
| | - Shan Jiang
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Jin Wei
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Jenna Chan
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Anish Thalakola
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Thanh Le
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Lan Xu
- College of Medicine, College of Public Health (L.X.), University of South Florida, Tampa
| | - Liang Zhao
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China (Y.C., L.Z.)
| | - Lei Wang
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| | - Kun Jiang
- Department of Anatomic Pathology, H. Lee Moffitt Cancer Center, Research Institute, Tampa, FL (K.J.)
| | - Feng Cheng
- Department of Pharmaceutical Science, College of Pharmacy (F.C.), University of South Florida, Tampa
| | - Trushar Patel
- Department of Urology (T.P.), University of South Florida, Tampa
| | - Jacentha Buggs
- Advanced Organ Disease and Transplantation Institute, Tampa General Hospital, FL (J.B.)
| | - Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA (V.V.)
| | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology (J.Z., X.W., S.J., J.W., J.C., A.T., T.L., L.W., R.L.), University of South Florida, Tampa
| |
Collapse
|
23
|
Navarro Garrido A, Kim YC, Goodluck H, Kanoo S, Crespo‐Masip M, Bröer S, Vallon V. Basal renal phenotype and response to induction of aristolochic acid nephropathy in mice lacking the neutral amino acid transporter B0AT1 (SLC6A19). FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.04004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Aleix Navarro Garrido
- Division of Nephrology & HypertensionDepartment of MedicineUniversity of California San Diego & VA San Diego Healthcare SystemLa JollaCA
| | - Young Chul Kim
- Division of Nephrology & HypertensionDepartment of MedicineUniversity of California San Diego & VA San Diego Healthcare SystemLa JollaCA
| | - Helen Goodluck
- Division of Nephrology & HypertensionDepartment of MedicineUniversity of California San Diego & VA San Diego Healthcare SystemLa JollaCA
| | - Sadhana Kanoo
- Division of Nephrology & HypertensionDepartment of MedicineUniversity of California San Diego & VA San Diego Healthcare SystemLa JollaCA
| | - Maria Crespo‐Masip
- Division of Nephrology & HypertensionDepartment of MedicineUniversity of California San Diego & VA San Diego Healthcare SystemLa JollaCA
| | - Stefan Bröer
- Research School of BiologyAustralian National UniversityCanberra
| | - Volker Vallon
- Division of Nephrology & HypertensionDepartment of MedicineUniversity of California San Diego & VA San Diego Healthcare SystemLa JollaCA
| |
Collapse
|
24
|
Kanoo S, Goodluck H, Kim YC, Garrido AN, Crespo‐Masip M, Zhang H, Villalobos RG, Ma L, Vallon V. Deletion of eNOS enhances kidney injury in BTBR ob/ob mice. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.04952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sadhana Kanoo
- MedicineUniversity of California San Diego & VA Medical CenterSan DiegoCA
| | - Helen Goodluck
- MedicineUniversity of California San Diego & VA Medical CenterSan DiegoCA
| | - Young Chul Kim
- MedicineUniversity of California San Diego & VA Medical CenterSan DiegoCA
| | | | | | - Haiyan Zhang
- MedicineUniversity of California San Diego & VA Medical CenterSan DiegoCA
| | | | - Li‐Jun Ma
- Cardiovascular & MetabolismJanssen, Johnson & JohnsonSpring HousePA
| | - Volker Vallon
- University of California San Diego & VA Medical CenterSan DiegoCA
| |
Collapse
|
25
|
Thomson SC, Vallon V. Effects of SGLT2 inhibitor and dietary NaCl on glomerular hemodynamics assessed by micropuncture in diabetic rats. Am J Physiol Renal Physiol 2021; 320:F761-F771. [PMID: 33645318 PMCID: PMC8174804 DOI: 10.1152/ajprenal.00552.2020] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 02/09/2021] [Accepted: 02/19/2021] [Indexed: 01/10/2023] Open
Abstract
Inhibitors of the main proximal tubular Na-glucose cotransporter (SGLT2) mitigate diabetic glomerular hyperfiltration and have been approved by the United States Food and Drug Administration for slowing the progression of diabetic kidney disease. It has been proposed that SGLT2 inhibitors improve hard renal outcomes by reducing glomerular capillary pressure (PGC) via a tubuloglomerular feedback (TGF) response to a decrease in proximal reabsorption (Jprox). However, the effect of SGLT2 inhibition on PGC has not been measured. Here, we studied the effects of acute SGLT2 blockade (ertugliflozin) on Jprox and glomerular hemodynamics in two-period micropuncture experiments using streptozotocin-induced diabetic rats fed high- or low-NaCl diets. PGC was measured by direct capillary puncture or computed from tubular stop-flow pressure (PSF). TGF is intact while measuring PGC directly but rendered inoperative when measuring PSF. Acute SGLT2 inhibitor reduced Jprox by ∼30%, reduced PGC by 5-8 mmHg, and reduced glomerular filtration rate (GFR) by ∼25% (all P < 0.0001) but had no effect on PSF. The decrease in PGC was larger with the low-NaCl diet (8 vs. 5 mmHg, P = 0.04) where PGC was higher to begin with (54 vs. 50 mmHg, P = 0.003). Greater decreases in PGC corresponded, unexpectedly, to lesser decreases in GFR (P = 0.04). In conclusion, these results confirm expectations that PGC would decline in response to acute SGLT2 inhibition and that a functioning TGF system is required for this. We infer a contribution of postglomerular vasorelaxation to the TGF responses where decreases in PGC were large and decreases in GFR were small.NEW & NOTEWORTHY It has been theorized that Na-glucose cotransporter (SGLT2) blockade slows progression of diabetic kidney disease by reducing physical strain on the glomerulus. This is the first direct measurement of intraglomerular pressure during SGLT2 blockade. Findings confirmed that SGLT2 blockade does reduce glomerular capillary pressure, that this is mediated through tubuloglomerular feedback, and that the tubuloglomerular feedback response to SGLT2 blockade involves preglomerular vasoconstriction and postglomerular vasorelaxation.
Collapse
Affiliation(s)
- Scott Culver Thomson
- Division of Nephrology-Hypertension, Department of Medicine, University of California, San Diego, California; and Veterans Affairs San Diego Healthcare System, La Jolla, California
| | - Volker Vallon
- Division of Nephrology-Hypertension, Department of Medicine, University of California, San Diego, California; and Veterans Affairs San Diego Healthcare System, La Jolla, California
| |
Collapse
|
26
|
Crespo‐Masip M, Pérez A, Guzmán C, Garcia A, Jover R, Vallon V, Valdivielso JM. Deletion of PTEN and VDR impair glucose and lipid metabolism. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.02397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Maria Crespo‐Masip
- Vascular & Renal Translational Research GroupIRB LleidaLleida
- Vallon labVeterans Affairs San Diego Healthcare SystemSan DiegoCA
| | - Aurora Pérez
- Vascular & Renal Translational Research GroupIRB LleidaLleida
| | - Carla Guzmán
- Experimental Hepatology UnitIIS Hospital La FeValencia
| | - Alicia Garcia
- Vascular & Renal Translational Research GroupIRB LleidaLleida
| | - Ramiro Jover
- Experimental Hepatology UnitIIS Hospital La FeValencia
| | - Volker Vallon
- Department of MedicineUniversity of California, San DiegoLa JollaCA
- Vallon labVeterans Affairs San Diego Healthcare SystemSan DiegoCA
| | | |
Collapse
|
27
|
Curtis LM, George J, Vallon V, Barnes S, Darley-Usmar V, Vaingankar S, Cutter GR, Gutierrez OM, Seifert M, Ix JH, Mehta RL, Sanders PW, Agarwal A. UAB-UCSD O'Brien Center for Acute Kidney Injury Research. Am J Physiol Renal Physiol 2021; 320:F870-F882. [PMID: 33779316 DOI: 10.1152/ajprenal.00661.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Acute kidney injury (AKI) remains a significant clinical problem through its diverse etiologies, the challenges of robust measurements of injury and recovery, and its progression to chronic kidney disease (CKD). Bridging the gap in our knowledge of this disorder requires bringing together not only the technical resources for research but also the investigators currently endeavoring to expand our knowledge and those who might bring novel ideas and expertise to this important challenge. The University of Alabama at Birmingham-University of California-San Diego O'Brien Center for Acute Kidney Injury Research brings together technical expertise and programmatic and educational efforts to advance our knowledge in these diverse issues and the required infrastructure to develop areas of novel exploration. Since its inception in 2008, this O'Brien Center has grown its impact by providing state-of-the-art resources in clinical and preclinical modeling of AKI, a bioanalytical core that facilitates measurement of critical biomarkers, including serum creatinine via LC-MS/MS among others, and a biostatistical resource that assists from design to analysis. Through these core resources and with additional educational efforts, our center has grown its investigator base to include >200 members from 51 institutions. Importantly, this center has translated its pilot and catalyst funding program with a $37 return per dollar invested. Over 500 publications have resulted from the support provided with a relative citation ratio of 2.18 ± 0.12 (iCite). Through its efforts, this disease-centric O'Brien Center is providing the infrastructure and focus to help the development of the next generation of researchers in the basic and clinical science of AKI. This center creates the promise of the application at the bedside of the advances in AKI made by current and future investigators.
Collapse
Affiliation(s)
- Lisa M Curtis
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - James George
- Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama
| | - Volker Vallon
- Division of Nephrology, Department of Medicine, University of California-San Diego, San Diego, California
| | - Stephen Barnes
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Victor Darley-Usmar
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Sucheta Vaingankar
- Division of Pediatric Nephrology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Gary R Cutter
- School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama
| | - Orlando M Gutierrez
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Michael Seifert
- Division of Pediatric Nephrology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Joachim H Ix
- Division of Nephrology, Department of Medicine, University of California-San Diego, San Diego, California
| | - Ravindra L Mehta
- Division of Nephrology, Department of Medicine, University of California-San Diego, San Diego, California
| | - Paul W Sanders
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama.,Department of Veterans Affairs, Birmingham, Alabama
| | - Anupam Agarwal
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama.,Department of Veterans Affairs, Birmingham, Alabama
| |
Collapse
|
28
|
Abstract
SGLT2 inhibitors are antihyperglycemic drugs that protect kidneys and the heart of patients with or without type 2 diabetes and preserved or reduced kidney function from failing. The involved protective mechanisms include blood glucose-dependent and -independent mechanisms: SGLT2 inhibitors prevent both hyper- and hypoglycemia, with expectedly little net effect on HbA1C. Metabolic adaptations to induced urinary glucose loss include reduced fat mass and more ketone bodies as additional fuel. SGLT2 inhibitors lower glomerular capillary hypertension and hyperfiltration, thereby reducing the physical stress on the filtration barrier, albuminuria, and the oxygen demand for tubular reabsorption. This improves cortical oxygenation, which, together with lesser tubular gluco-toxicity, may preserve tubular function and glomerular filtration rate in the long term. SGLT2 inhibitors may mimic systemic hypoxia and stimulate erythropoiesis, which improves organ oxygen delivery. SGLT2 inhibitors are proximal tubule and osmotic diuretics that reduce volume retention and blood pressure and preserve heart function, potentially in part by overcoming the resistance to diuretics and atrial-natriuretic-peptide and inhibiting Na-H exchangers and sympathetic tone.
Collapse
Affiliation(s)
- Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California, San Diego, La Jolla, California 92093, USA;
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, USA
- VA San Diego Healthcare System, San Diego, California 92161, USA
| | - Subodh Verma
- Division of Cardiac Surgery, St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada;
- Departments of Surgery and Pharmacology and Toxicology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| |
Collapse
|
29
|
Tuttle KR, Brosius FC, Cavender MA, Fioretto P, Fowler KJ, Heerspink HJ, Manley T, McGuire DK, Molitch ME, Mottl AK, Perreault L, Rosas SE, Rossing P, Sola L, Vallon V, Wanner C, Perkovic V. SGLT2 Inhibition for CKD and Cardiovascular Disease in Type 2 Diabetes: Report of a Scientific Workshop Sponsored by the National Kidney Foundation. Am J Kidney Dis 2021; 77:94-109. [DOI: 10.1053/j.ajkd.2020.08.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 08/04/2020] [Indexed: 12/25/2022]
|
30
|
Tuttle KR, Brosius FC, Cavender MA, Fioretto P, Fowler KJ, Heerspink HJL, Manley T, McGuire DK, Molitch ME, Mottl AK, Perreault L, Rosas SE, Rossing P, Sola L, Vallon V, Wanner C, Perkovic V. SGLT2 Inhibition for CKD and Cardiovascular Disease in Type 2 Diabetes: Report of a Scientific Workshop Sponsored by the National Kidney Foundation. Diabetes 2021; 70:1-16. [PMID: 33106255 PMCID: PMC8162454 DOI: 10.2337/dbi20-0040] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 08/04/2020] [Indexed: 12/24/2022]
Abstract
Diabetes is the most frequent cause of chronic kidney disease (CKD), leading to nearly half of all cases of kidney failure requiring replacement therapy. The principal cause of death among patients with diabetes and CKD is cardiovascular disease (CVD). Sodium/glucose cotransporter 2 (SGLT2) inhibitors were developed to lower blood glucose levels by inhibiting glucose reabsorption in the proximal tubule. In clinical trials designed to demonstrate the CVD safety of SGLT2 inhibitors in type 2 diabetes mellitus (T2DM), consistent reductions in risks for secondary kidney disease end points (albuminuria and a composite of serum creatinine doubling or 40% estimated glomerular filtration rate decline, kidney failure, or death), along with reductions in CVD events, were observed. In patients with CKD, the kidney and CVD benefits of canagliflozin were established by the CREDENCE (Canagliflozin and Renal Events in Diabetes With Established Nephropathy Clinical Evaluation) trial in patients with T2DM, urinary albumin-creatinine ratio >300 mg/g, and estimated glomerular filtration rate of 30 to <90 mL/min/1.73 m2 To clarify and support the role of SGLT2 inhibitors for treatment of T2DM and CKD, the National Kidney Foundation convened a scientific workshop with an international panel of more than 80 experts. They discussed the current state of knowledge and unanswered questions in order to propose therapeutic approaches and delineate future research. SGLT2 inhibitors improve glomerular hemodynamic function and are thought to ameliorate other local and systemic mechanisms involved in the pathogenesis of CKD and CVD. SGLT2 inhibitors should be used when possible by people with T2DM to reduce risks for CKD and CVD in alignment with the clinical trial entry criteria. Important risks of SGLT2 inhibitors include euglycemic ketoacidosis, genital mycotic infections, and volume depletion. Careful consideration should be given to the balance of benefits and harms of SGLT2 inhibitors and risk mitigation strategies. Effective implementation strategies are needed to achieve widespread use of these life-saving medications.
Collapse
Affiliation(s)
- Katherine R Tuttle
- Providence Health Care and University of Washington School of Medicine, Spokane, WA
| | | | | | - Paola Fioretto
- Department of Medicine, University of Padua, Padua, Italy
| | | | | | - Tom Manley
- National Kidney Foundation, New York, NY
| | | | - Mark E Molitch
- Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern, University Feinberg School of Medicine, Chicago, IL
| | - Amy K Mottl
- University of North Carolina School of Medicine, Chapel Hill, NC
| | | | - Sylvia E Rosas
- Joslin Diabetes Center and Harvard Medical School, Boston, MA
| | - Peter Rossing
- Steno Diabetes Center Copenhagen, Gentofte, Denmark
- University of Copenhagen, Copenhagen, Denmark
| | - Laura Sola
- University of the Republic, Montevideo, Uruguay
| | | | - Christoph Wanner
- Division of Nephrology, University Hospital Würzburg, Würzburg, Germany
| | - Vlado Perkovic
- George Institute for Global Health, UNSW Sydney, Australia
| |
Collapse
|
31
|
Onishi A, Fu Y, Patel R, Darshi M, Crespo-Masip M, Huang W, Song P, Freeman B, Kim YC, Soleimani M, Sharma K, Thomson SC, Vallon V. A role for tubular Na +/H + exchanger NHE3 in the natriuretic effect of the SGLT2 inhibitor empagliflozin. Am J Physiol Renal Physiol 2020; 319:F712-F728. [PMID: 32893663 DOI: 10.1152/ajprenal.00264.2020] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Inhibitors of proximal tubular Na+-glucose cotransporter 2 (SGLT2) are natriuretic, and they lower blood pressure. There are reports that the activities of SGLT2 and Na+-H+ exchanger 3 (NHE3) are coordinated. If so, then part of the natriuretic response to an SGLT2 inhibitor is mediated by suppressing NHE3. To examine this further, we compared the effects of an SGLT2 inhibitor, empagliflozin, on urine composition and systolic blood pressure (SBP) in nondiabetic mice with tubule-specific NHE3 knockdown (NHE3-ko) and wild-type (WT) littermates. A single dose of empagliflozin, titrated to cause minimal glucosuria, increased urinary excretion of Na+ and bicarbonate and raised urine pH in WT mice but not in NHE3-ko mice. Chronic empagliflozin treatment tended to lower SBP despite higher renal renin mRNA expression and lowered the ratio of SBP to renin mRNA, indicating volume loss. This effect of empagliflozin depended on tubular NHE3. In diabetic Akita mice, chronic empagliflozin enhanced phosphorylation of NHE3 (S552/S605), changes previously linked to lesser NHE3-mediated reabsorption. Chronic empagliflozin also increased expression of genes involved with renal gluconeogenesis, bicarbonate regeneration, and ammonium formation. While this could reflect compensatory responses to acidification of proximal tubular cells resulting from reduced NHE3 activity, these effects were at least in part independent of tubular NHE3 and potentially indicated metabolic adaptations to urinary glucose loss. Moreover, empagliflozin increased luminal α-ketoglutarate, which may serve to stimulate compensatory distal NaCl reabsorption, while cogenerated and excreted ammonium balances urine losses of this "potential bicarbonate." The data implicate NHE3 as a determinant of the natriuretic effect of empagliflozin.
Collapse
Affiliation(s)
- Akira Onishi
- Department of Medicine, University of California-San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Yiling Fu
- Department of Medicine, University of California-San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Rohit Patel
- Department of Medicine, University of California-San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Manjula Darshi
- Center for Renal Precision Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Maria Crespo-Masip
- Department of Medicine, University of California-San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California.,Biomedical Research Institute, University of Lleida, Lleida, Spain
| | - Winnie Huang
- Department of Medicine, University of California-San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Panai Song
- Department of Medicine, University of California-San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Brent Freeman
- Department of Medicine, University of California-San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Young Chul Kim
- Department of Medicine, University of California-San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | | | - Kumar Sharma
- Center for Renal Precision Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Scott Culver Thomson
- Department of Medicine, University of California-San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Volker Vallon
- Department of Medicine, University of California-San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| |
Collapse
|
32
|
Kim YC, Ganguly S, Nespoux J, Freeman B, Zhang H, Brenner D, Dhar D, Vallon V. Western Diet Promotes Renal Injury, Inflammation, and Fibrosis in a Murine Model of Alström Syndrome. Nephron Clin Pract 2020; 144:400-412. [PMID: 32629454 DOI: 10.1159/000508636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 05/12/2020] [Indexed: 12/26/2022] Open
Abstract
INTRODUCTION Alström syndrome is a rare recessive genetic disease caused by mutations in ALMS1, which encodes a protein that is related to cilia function and intracellular endosome trafficking. The syndrome has been linked to impaired glucose metabolism and CKD. Polymorphisms in Alms1 have likewise been linked to CKD, but little is known about the modification of the phenotype by environmental factors. METHODS To gain further insights, the fat aussie (foz) mouse strain, a genetic murine model of Alström syndrome, was exposed to a normal chow (NC) or to a Western diet (WD, 20% fat, 34% sucrose by weight, and 0.2% cholesterol) and renal outcomes were measured. RESULTS Body weight and albuminuria were higher in foz than in wild-type (WT) mice on both diets but WD significantly increased the difference. Measurement of plasma creatinine and cystatin C indicated that glomerular filtration rate was preserved in foz versus WT independent of diet. Renal markers of injury, inflammation, and fibrosis were similar in both genotypes on NC but significantly greater in foz than in WT mice on WD. A glucose tolerance test performed in foz and WT mice on WD revealed similar basal blood glucose levels and subsequent blood glucose profiles. CONCLUSIONS WD sensitizes a murine model of Alström syndrome to kidney injury, inflammation, and fibrosis, an effect that may not be solely due to effects on glucose metabolism. Polymorphisms in Alms1 may induce CKD in part by modulating the deleterious effects of high dietary fat and sucrose on kidney outcome.
Collapse
Affiliation(s)
- Young Chul Kim
- Division of Nephrology & Hypertension, Department of Medicine, University of California San Diego & VA San Diego Healthcare System, San Diego, California, USA
| | - Souradipta Ganguly
- Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Josselin Nespoux
- Division of Nephrology & Hypertension, Department of Medicine, University of California San Diego & VA San Diego Healthcare System, San Diego, California, USA
| | - Brent Freeman
- Division of Nephrology & Hypertension, Department of Medicine, University of California San Diego & VA San Diego Healthcare System, San Diego, California, USA
| | - Haiyan Zhang
- Division of Nephrology & Hypertension, Department of Medicine, University of California San Diego & VA San Diego Healthcare System, San Diego, California, USA
| | - David Brenner
- Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Debanjan Dhar
- Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Volker Vallon
- Division of Nephrology & Hypertension, Department of Medicine, University of California San Diego & VA San Diego Healthcare System, San Diego, California, USA,
| |
Collapse
|
33
|
Hesp AC, Schaub JA, Prasad PV, Vallon V, Laverman GD, Bjornstad P, van Raalte DH. The role of renal hypoxia in the pathogenesis of diabetic kidney disease: a promising target for newer renoprotective agents including SGLT2 inhibitors? Kidney Int 2020; 98:579-589. [PMID: 32739206 DOI: 10.1016/j.kint.2020.02.041] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/06/2020] [Accepted: 02/26/2020] [Indexed: 12/17/2022]
Abstract
Diabetic kidney disease is the most common cause of end-stage kidney disease and poses a major global health problem. Finding new, safe, and effective strategies to halt this disease has proven to be challenging. In part that is because the underlying mechanisms are complex and not fully understood. However, in recent years, evidence has accumulated suggesting that chronic hypoxia may be the primary pathophysiological pathway driving diabetic kidney disease and chronic kidney disease of other etiologies and was called the chronic hypoxia hypothesis. Hypoxia is the result of a mismatch between oxygen delivery and oxygen demand. The primary determinant of oxygen delivery is renal perfusion (blood flow per tissue mass), whereas the main driver of oxygen demand is active sodium reabsorption. Diabetes mellitus is thought to compromise the oxygen balance by impairing oxygen delivery owing to hyperglycemia-associated microvascular damage and exacerbate oxygen demand owing to increased sodium reabsorption as a result of sodium-glucose cotransporter upregulation and glomerular hyperfiltration. The resultant hypoxic injury creates a vicious cycle of capillary damage, inflammation, deposition of the extracellular matrix, and, ultimately, fibrosis and nephron loss. This review will frame the role of chronic hypoxia in the pathogenesis of diabetic kidney disease and its prospect as a promising therapeutic target. We will outline the cellular mechanisms of hypoxia and evidence for renal hypoxia in animal and human studies. In addition, we will highlight the promise of newer imaging modalities including blood oxygenation level-dependent magnetic resonance imaging and discuss salutary interventions such as sodium-glucose cotransporter 2 inhibition that (may) protect the kidney through amelioration of renal hypoxia.
Collapse
Affiliation(s)
- Anne C Hesp
- Diabetes Center, Department of Internal Medicine, Amsterdam University Medical Centers, location VUMC, Amsterdam, The Netherlands.
| | - Jennifer A Schaub
- Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA
| | - Pottumarthi V Prasad
- Department of Radiology, NorthShore University Health System, Evanston, Illinois, USA; Pritzker School of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Volker Vallon
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California, USA
| | - Gozewijn D Laverman
- Department of Internal Medicine, Ziekenhuis Groep Twente, Almelo, The Netherlands
| | - Petter Bjornstad
- Department of Medicine, Division of Nephrology, and Section of Endocrinology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Daniël H van Raalte
- Diabetes Center, Department of Internal Medicine, Amsterdam University Medical Centers, location VUMC, Amsterdam, The Netherlands
| |
Collapse
|
34
|
|
35
|
Kim YC, Ganguly S, Nespoux J, Freeman B, Zhang H, Brenner D, Dhar D, Vallon V. Western diet promotes renal injury, inflammation, and fibrosis in a murine model of Alström syndrome. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.01760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Young Chul Kim
- University of California-San Diego
- VA San Diego Healthcare System
| | | | | | | | | | | | | | - Volker Vallon
- University of California-San Diego
- VA San Diego Healthcare System
| |
Collapse
|
36
|
Nespoux J, Patel R, Zhang H, Huang W, Freeman B, Kim YC, Vallon V. Absence of Na‐Glucose Cotransporter SGLT2 Does Not Protect the Kidney in a Murine Model of Renal Ischemia‐Reperfusion Injury. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.02027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Josselin Nespoux
- Department of Medicine University of California, San Diego & VA San Diego Healthcare System
| | - Rohit Patel
- Department of Medicine University of California, San Diego & VA San Diego Healthcare System
| | - Haiyan Zhang
- Department of Pathology University of California San Diego
| | - Winnie Huang
- Department of Medicine University of California, San Diego & VA San Diego Healthcare System
| | - Brent Freeman
- Department of Medicine University of California, San Diego & VA San Diego Healthcare System
| | - Young Chul Kim
- Department of Medicine University of California, San Diego & VA San Diego Healthcare System
| | - Volker Vallon
- Department of Medicine University of California, San Diego & VA San Diego Healthcare System
- Department of Pharmacology University of California San Diego
| |
Collapse
|
37
|
Abstract
Kidney size and glomerular filtration rate (GFR) often increase with the onset of diabetes, and elevated GFR is a risk factor for the development of diabetic kidney disease. Hyperfiltration mainly occurs in response to signals passed from the tubule to the glomerulus: high levels of glucose in the glomerular filtrate drive increased reabsorption of glucose and sodium by the sodium-glucose cotransporters SGLT2 and SGLT1 in the proximal tubule. Passive reabsorption of chloride and water also increases. The overall capacity for proximal reabsorption is augmented by growth of the proximal tubule, which (alongside sodium-glucose cotransport) further limits urinary glucose loss. Hyperreabsorption of sodium and chloride induces tubuloglomerular feedback from the macula densa to increase GFR. In addition, sodium-glucose cotransport by SGLT1 on macula densa cells triggers the production of nitric oxide, which also contributes to glomerular hyperfiltration. Although hyperfiltration restores sodium and chloride excretion it imposes added physical stress on the filtration barrier and increases the oxygen demand to drive reabsorption. Tubular growth is associated with the development of a senescence-like molecular signature that sets the stage for inflammation and fibrosis. SGLT2 inhibitors attenuate the proximal reabsorption of sodium and glucose, normalize tubuloglomerular feedback signals and mitigate hyperfiltration. This tubule-centred model of diabetic kidney physiology predicts the salutary effect of SGLT2 inhibitors on hard renal outcomes, as shown in large-scale clinical trials.
Collapse
Affiliation(s)
- Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA, USA. .,Department of Pharmacology, University of California San Diego, La Jolla, CA, USA. .,VA San Diego Healthcare System, San Diego, CA, USA.
| | - Scott C Thomson
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA, USA.,VA San Diego Healthcare System, San Diego, CA, USA
| |
Collapse
|
38
|
Abstract
The kidneys filter large amounts of glucose. To prevent the loss of this valuable fuel, the tubular system of the kidney, particularly the proximal tubule, has been programmed to reabsorb all filtered glucose. The machinery involves the sodium-glucose cotransporters SGLT2 and SGLT1 on the apical membrane and the facilitative glucose transporter GLUT2 on the basolateral membrane. The proximal tubule also generates new glucose, particularly in the post-absorptive phase but also to enhance bicarbonate formation and maintain acid-base balance. The glucose reabsorbed or formed by the proximal tubule is primarily taken up into peritubular capillaries and returned to the systemic circulation or provided as an energy source to further distal tubular segments that take up glucose by basolateral GLUT1. Recent studies provided insights on the coordination of renal glucose reabsorption, formation, and usage. Moreover, a better understanding of renal glucose transport in disease states is emerging. This includes the kidney in diabetes mellitus, when renal glucose retention becomes maladaptive and contributes to hyperglycemia. Furthermore, enhanced glucose reabsorption is coupled to sodium retention through the sodium-glucose cotransporter SGLT2, which induces secondary deleterious effects. As a consequence, SGLT2 inhibitors are new anti-hyperglycemic drugs that can protect the kidneys and heart from failing. Recent studies discovered unique roles for SGLT1 with implications in acute kidney injury and glucose sensing at the macula densa. This review discusses established and emerging concepts of renal glucose transport, and outlines the need for a better understanding of renal glucose handling in health and disease.
Collapse
Affiliation(s)
- Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA, USA.
- Department of Pharmacology, University of California San Diego, La Jolla, CA, USA.
- VA San Diego Healthcare System, San Diego, CA, USA.
| |
Collapse
|
39
|
Nespoux J, Patel R, Zhang H, Huang W, Freeman B, Sanders PW, Kim YC, Vallon V. Gene knockout of the Na +-glucose cotransporter SGLT2 in a murine model of acute kidney injury induced by ischemia-reperfusion. Am J Physiol Renal Physiol 2020; 318:F1100-F1112. [PMID: 32116018 DOI: 10.1152/ajprenal.00607.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In the early proximal tubule, Na+-glucose cotransporter 2 (SGLT2) mediates the bulk of renal glucose reabsorption. Gene deletion in mice (Sglt2-/-) was used to determine the role of SGLT2 in acute kidney injury induced by bilateral ischemia-reperfusion (IR). In Sglt2-/- and littermate wild-type mice, plasma creatinine increased similarly on day 1 after IR. This was associated with an equal increase in both genotypes in the urinary kidney injury molecule-1-to-creatinine ratio, a tubular injury marker, and similarly reduced urine osmolality and increased plasma osmolality, indicating impaired urine concentration. In both IR groups, FITC-sinistrin glomerular filtration rate was equally reduced on day 14, and plasma creatinine was similarly and incompletely restored on day 23. In Sglt2-/- mice subjected to IR, fractional urinary glucose excretion was increased on day 1 but reduced and associated with normal renal Na+-glucose cotransporter 1 (Sglt1) mRNA expression on day 23, suggesting temporary SGLT1 suppression. In wild-type mice subjected to IR, renal Sglt1 mRNA was likewise normal on day 23, whereas Sglt2 mRNA was reduced by 57%. In both genotypes, IR equally reduced urine osmolality and renal mRNA expression of the Na+-K+-2Cl- cotransporter and renin on day 23, suggesting thick ascending limb dysfunction, and similarly increased renal mRNA expression of markers of injury, inflammation, oxidative stress, and fibrosis (kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, transforming growth factor-β1, NADPH oxidase-2, and collagen type 1). This was associated with equal increases in kidney histological damage scores and similar degree of capillary loss in both genotypes. The data indicate that genetic deletion of SGLT2 did not protect the kidneys in the initial injury phase or the subsequent recovery phase in a mouse model of IR-induced acute kidney injury.
Collapse
Affiliation(s)
- Josselin Nespoux
- Department of Medicine, University of California, and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Rohit Patel
- Department of Medicine, University of California, and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Haiyan Zhang
- Department of Pathology, University of California, San Diego, California
| | - Winnie Huang
- Department of Medicine, University of California, and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Brent Freeman
- Department of Medicine, University of California, and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Paul W Sanders
- Departments of Medicine, Cell, and Developmental and Integrative Biology, University of Alabama at Birmingham, and Department of Veterans Affairs Medical Center, Birmingham, Alabama
| | - Young Chul Kim
- Department of Medicine, University of California, and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Volker Vallon
- Department of Medicine, University of California, and Veterans Affairs San Diego Healthcare System , San Diego, California.,Department of Pharmacology, University of California, San Diego, California
| |
Collapse
|
40
|
Masuda T, Muto S, Fukuda K, Watanabe M, Ohara K, Koepsell H, Vallon V, Nagata D. Osmotic diuresis by SGLT2 inhibition stimulates vasopressin-induced water reabsorption to maintain body fluid volume. Physiol Rep 2020; 8:e14360. [PMID: 31994353 PMCID: PMC6987478 DOI: 10.14814/phy2.14360] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 01/02/2020] [Accepted: 01/05/2020] [Indexed: 12/25/2022] Open
Abstract
Most of the filtered glucose is reabsorbed in the early proximal tubule by the sodium-glucose cotransporter SGLT2. The glycosuric effect of the SGLT2 inhibitor ipragliflozin is linked to a diuretic and natriuretic effect that activates compensatory increases in fluid and food intake to stabilize body fluid volume (BFV). However, the compensatory mechanisms that are activated on the level of renal tubules remain unclear. Type 2 diabetic Goto-Kakizaki (GK) rats were treated with vehicle or 0.01% (in diet) ipragliflozin with free access to fluid and food. After 8 weeks, GK rats were placed in metabolic cages for 24-hr. Ipragliflozin decreased body weight, serum glucose and systolic blood pressure, and increased fluid and food intake, urinary glucose and Na+ excretion, urine volume, and renal osmolar clearance, as well as urine vasopressin and solute-free water reabsorption (TcH2O). BFV, measured by bioimpedance spectroscopy, and fluid balance were similar among the two groups. Urine vasopressin in ipragliflozin-treated rats was negatively and positively associated with fluid balance and TcH2O, respectively. Ipragliflozin increased the renal membrane protein expression of SGLT2, aquaporin (AQP) 2 phosphorylated at Ser269 and vasopressin V2 receptor. The expression of SGLT1, GLUT2, AQP1, and AQP2 was similar between the groups. In conclusion, the SGLT2 inhibitor ipragliflozin induced a sustained glucosuria, diuresis, and natriuresis, with compensatory increases in fluid intake and vasopressin-induced TcH2O in proportion to the reduced fluid balance to maintain BFV. These results indicate that the osmotic diuresis induced by SGLT2 inhibition stimulates compensatory fluid intake and renal water reabsorption to maintain BFV.
Collapse
Affiliation(s)
- Takahiro Masuda
- Division of NephrologyDepartment of Internal MedicineJichi Medical UniversityShimotsukeTochigiJapan
| | - Shigeaki Muto
- Division of NephrologyDepartment of Internal MedicineJichi Medical UniversityShimotsukeTochigiJapan
| | - Keiko Fukuda
- Division of NephrologyDepartment of Internal MedicineJichi Medical UniversityShimotsukeTochigiJapan
| | - Minami Watanabe
- Division of NephrologyDepartment of Internal MedicineJichi Medical UniversityShimotsukeTochigiJapan
| | - Ken Ohara
- Division of NephrologyDepartment of Internal MedicineJichi Medical UniversityShimotsukeTochigiJapan
| | - Hermann Koepsell
- Department of Molecular Plant Physiology and BiophysicsJulius‐von‐Sachs‐Institute of BiosciencesUniversity of WürzburgWürzburgBavariaGermany
| | - Volker Vallon
- Division of Nephrology and HypertensionDepartment of Medicine and PharmacologyUniversity of California San Diego &VA San Diego Healthcare SystemSan DiegoCAUSA
| | - Daisuke Nagata
- Division of NephrologyDepartment of Internal MedicineJichi Medical UniversityShimotsukeTochigiJapan
| |
Collapse
|
41
|
Abstract
Sodium-glucose co-transporter 2 (SGLT2) inhibitors immediately reduce the glomerular filtration rate (GFR) in patients with type 2 diabetes mellitus. When given chronically, they confer benefit by markedly slowing the rate at which chronic kidney disease progresses and are the first agents to do so since the advent of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs). Salutary effects on the kidney were first demonstrated in cardiovascular outcomes trials and have now emerged from trials enriched in subjects with type 2 diabetes mellitus and chronic kidney disease. A simple model that unifies the immediate and long-term effects of SGLT2 inhibitors on kidney function is based on the assumption that diabetic hyperfiltration puts the kidney at long-term risk and evidence that hyperfiltration is an immediate response to a reduced signal for tubuloglomerular feedback, which occurs to the extent that SGLT2 activity mediates a primary increase in sodium and fluid reabsorption by the proximal tubule. This model will likely continue to serve as a useful description accounting for the beneficial effect of SGLT2 inhibitors on the diabetic kidney, similar to the hemodynamic explanation for the benefit of ACEIs and ARBs. A more complex model will be required to incorporate positive interactions between SGLT2 and sodium-hydrogen exchanger 3 in the proximal tubule and between sodium-glucose co-transporter 1 (SGLT1) and nitric oxide synthase in the macula densa. The implication of these latter nuances for day-to-day clinical medicine remains to be determined.
Collapse
|
42
|
Abstract
The understanding of the nucleotide/P2 receptor system in the regulation of renal hemodynamics and transport function has grown exponentially over the last 20 yr. This review attempts to integrate the available data while also identifying areas of missing information. First, the determinants of nucleotide concentrations in the interstitial and tubular fluids of the kidney are described, including mechanisms of cellular release of nucleotides and their extracellular breakdown. Then the renal cell membrane expression of P2X and P2Y receptors is discussed in the context of their effects on renal vascular and tubular functions. Attention is paid to effects on the cortical vasculature and intraglomerular structures, autoregulation of renal blood flow, tubuloglomerular feedback, and the control of medullary blood flow. The role of the nucleotide/P2 receptor system in the autocrine/paracrine regulation of sodium and fluid transport in the tubular and collecting duct system is outlined together with its role in integrative sodium and fluid homeostasis and blood pressure control. The final section summarizes the rapidly growing evidence indicating a prominent role of the extracellular nucleotide/P2 receptor system in the pathophysiology of the kidney and aims to identify potential therapeutic opportunities, including hypertension, lithium-induced nephropathy, polycystic kidney disease, and kidney inflammation. We are only beginning to unravel the distinct physiological and pathophysiological influences of the extracellular nucleotide/P2 receptor system and the associated therapeutic perspectives.
Collapse
Affiliation(s)
- Volker Vallon
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Robert Unwin
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Edward W Inscho
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Jens Leipziger
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Bellamkonda K Kishore
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| |
Collapse
|
43
|
Onishi A, Fu Y, Darshi M, Crespo-Masip M, Huang W, Song P, Patel R, Kim YC, Nespoux J, Freeman B, Soleimani M, Thomson S, Sharma K, Vallon V. Effect of renal tubule-specific knockdown of the Na +/H + exchanger NHE3 in Akita diabetic mice. Am J Physiol Renal Physiol 2019; 317:F419-F434. [PMID: 31166707 PMCID: PMC6732454 DOI: 10.1152/ajprenal.00497.2018] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 05/21/2019] [Accepted: 05/27/2019] [Indexed: 01/03/2023] Open
Abstract
Na+/H+ exchanger isoform 3 (NHE3) contributes to Na+/bicarbonate reabsorption and ammonium secretion in early proximal tubules. To determine its role in the diabetic kidney, type 1 diabetic Akita mice with tubular NHE3 knockdown [Pax8-Cre; NHE3-knockout (KO) mice] were generated. NHE3-KO mice had higher urine pH, more bicarbonaturia, and compensating increases in renal mRNA expression for genes associated with generation of ammonium, bicarbonate, and glucose (phosphoenolpyruvate carboxykinase) in proximal tubules and H+ and ammonia secretion and glycolysis in distal tubules. This left blood pH and bicarbonate unaffected in nondiabetic and diabetic NHE3-KO versus wild-type mice but was associated with renal upregulation of proinflammatory markers. Higher renal phosphoenolpyruvate carboxykinase expression in NHE3-KO mice was associated with lower Na+-glucose cotransporter (SGLT)2 and higher SGLT1 expression, indicating a downward tubular shift in Na+ and glucose reabsorption. NHE3-KO was associated with lesser kidney weight and glomerular filtration rate (GFR) independent of diabetes and prevented diabetes-associated albuminuria. NHE3-KO, however, did not attenuate hyperglycemia or prevent diabetes from increasing kidney weight and GFR. Higher renal gluconeogenesis may explain similar hyperglycemia despite lower SGLT2 expression and higher glucosuria in diabetic NHE3-KO versus wild-type mice; stronger SGLT1 engagement could have affected kidney weight and GFR responses. Chronic kidney disease in humans is associated with reduced urinary excretion of metabolites of branched-chain amino acids and the tricarboxylic acid cycle, a pattern mimicked in diabetic wild-type mice. This pattern was reversed in nondiabetic NHE3-KO mice, possibly reflecting branched-chain amino acids use for ammoniagenesis and tricarboxylic acid cycle upregulation to support formation of ammonia, bicarbonate, and glucose in proximal tubule. NHE3-KO, however, did not prevent the diabetes-induced urinary downregulation in these metabolites.
Collapse
Affiliation(s)
- Akira Onishi
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Yiling Fu
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Manjula Darshi
- Center for Renal Precision Medicine, University of Texas Health San Antonio, San Antonio, Texas
| | - Maria Crespo-Masip
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
- Biomedical Research Institute (IRBLleida), University of Lleida, Lleida, Spain
| | - Winnie Huang
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Panai Song
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Rohit Patel
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Young Chul Kim
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Josselin Nespoux
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Brent Freeman
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | | | - Scott Thomson
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Kumar Sharma
- Center for Renal Precision Medicine, University of Texas Health San Antonio, San Antonio, Texas
| | - Volker Vallon
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System, San Diego, California
| |
Collapse
|
44
|
Abstract
A deficit or loss in the number of nephrons, the functional unit of the kidney, can induce compensatory growth and hyperfunction of remaining nephrons. An increase in single nephron glomerular filtration rate (SNGFR) aims to compensate but may be deleterious in the long term. The increase in SNGFR is determined by the dynamics of nephron loss, total remaining GFR, the body's excretory demand, and the functional capacity to sustain single nephron hyperfunction.
Collapse
Affiliation(s)
- Hadi Fattah
- Departments of Medicine and Pharmacology, Division of Nephrology and Hypertension, University of California San Diego , San Diego, California.,Department of Veterans Affairs, San Diego Healthcare System, San Diego, California
| | - Anita Layton
- Department of Applied Mathematics and School of Pharmacy, University of Waterloo , Waterloo, Ontario , Canada.,Departments of Mathematics, Biomedical Engineering, and Medicine, Duke University , Durham, North Carolina
| | - Volker Vallon
- Departments of Medicine and Pharmacology, Division of Nephrology and Hypertension, University of California San Diego , San Diego, California.,Department of Veterans Affairs, San Diego Healthcare System, San Diego, California
| |
Collapse
|
45
|
Nespoux J, Patel R, Hudkins KL, Huang W, Freeman B, Kim YC, Koepsell H, Alpers CE, Vallon V. Gene deletion of the Na +-glucose cotransporter SGLT1 ameliorates kidney recovery in a murine model of acute kidney injury induced by ischemia-reperfusion. Am J Physiol Renal Physiol 2019; 316:F1201-F1210. [PMID: 30995111 PMCID: PMC6620597 DOI: 10.1152/ajprenal.00111.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/05/2019] [Accepted: 04/10/2019] [Indexed: 12/12/2022] Open
Abstract
Renal Na+-glucose cotransporter SGLT1 mediates glucose reabsorption in the late proximal tubule, a hypoxia-sensitive tubular segment that enters the outer medulla. Gene deletion in mice (Sglt1-/-) was used to determine the role of the cotransporter in acute kidney injury induced by ischemia-reperfusion (IR), including the initial injury and subsequent recovery phase. On days 1 and 16 after IR, absolute and fractional urinary glucose excretion remained greater in Sglt1-/- mice versus wild-type (WT) littermates, consistent with a sustained contribution of SGLT1 to tubular glucose reabsorption in WT mice. Absence of SGLT1 did not affect the initial kidney impairment versus WT mice, as indicated by similar increases on day 1 in plasma concentrations of creatinine and urinary excretion of the tubular injury marker kidney injury molecule-1 as well as a similar rise in plasma osmolality and fall in urine osmolality as indicators of impaired urine concentration. Recovery of kidney function on days 14/16, however, was improved in Sglt1-/- versus WT mice, as indicated by lower plasma creatinine, higher glomerula filtration rate (by FITC-sinistrin in awake mice), and more completely restored urine and plasma osmolality. This was associated with a reduced tubular injury score in the cortex and outer medulla, better preserved renal mRNA expression of tubular transporters (Sglt2 and Na+-K+-2Cl- cotransporter Nkcc2), and a lesser rise in renal mRNA expression of markers of injury, inflammation, and fibrosis [kidney injury molecule-1, chemokine (C-C motif) ligand 2, fibronectin 1, and collagen type I-α1] in Sglt1-/- versus WT mice. These results suggest that SGLT1 activity in the late proximal tubule may have deleterious effects during recovery of IR-induced acute kidney injury and identify SGLT1 as a potential therapeutic target.
Collapse
Affiliation(s)
- Josselin Nespoux
- Department of Medicine, University of California , San Diego, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Rohit Patel
- Department of Medicine, University of California , San Diego, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Kelly L Hudkins
- Department of Pathology, University of Washington , Seattle, Washington
| | - Winnie Huang
- Department of Medicine, University of California , San Diego, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Brent Freeman
- Department of Medicine, University of California , San Diego, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Young Chul Kim
- Department of Medicine, University of California , San Diego, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Hermann Koepsell
- Department of Molecular Plant Physiology, University Würzburg , Würzburg , Germany
| | - Charles E Alpers
- Department of Pathology, University of Washington , Seattle, Washington
| | - Volker Vallon
- Department of Medicine, University of California , San Diego, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
- Department of Pharmacology, University of California , San Diego, California
| |
Collapse
|
46
|
Song P, Huang W, Onishi A, Patel R, Kim YC, van Ginkel C, Fu Y, Freeman B, Koepsell H, Thomson S, Liu R, Vallon V. Knockout of Na +-glucose cotransporter SGLT1 mitigates diabetes-induced upregulation of nitric oxide synthase NOS1 in the macula densa and glomerular hyperfiltration. Am J Physiol Renal Physiol 2019; 317:F207-F217. [PMID: 31091127 DOI: 10.1152/ajprenal.00120.2019] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Na+-glucose cotransporter (SGLT)1 mediates glucose reabsorption in late proximal tubules. SGLT1 also mediates macula densa (MD) sensing of an increase in luminal glucose, which increases nitric oxide (NO) synthase 1 (MD-NOS1)-mediated NO formation and potentially glomerular filtratrion rate (GFR). Here, the contribution of SGLT1 was tested by gene knockout (-/-) in type 1 diabetic Akita mice. A low-glucose diet was used to prevent intestinal malabsorption in Sglt1-/- mice and minimize the contribution of intestinal SGLT1. Hyperglycemia was modestly reduced in Sglt1-/- versus littermate wild-type Akita mice (480 vs. 550 mg/dl), associated with reduced diabetes-induced increases in GFR, kidney weight, glomerular size, and albuminuria. Blunted hyperfiltration was confirmed in streptozotocin-induced diabetic Sglt1-/- mice, associated with similar hyperglycemia versus wild-type mice (350 vs. 385 mg/dl). Absence of SGLT1 attenuated upregulation of MD-NOS1 protein expression in diabetic Akita mice and in response to SGLT2 inhibition in nondiabetic mice. During SGLT2 inhibition in Akita mice, Sglt1-/- mice had likewise reduced blood glucose (200 vs. 300 mg/dl), associated with lesser MD-NOS1 expression, GFR, kidney weight, glomerular size, and albuminuria. Absence of Sglt1 in Akita mice increased systolic blood pressure, associated with suppressed renal renin mRNA expression. This may reflect fluid retention due to blunted hyperfiltration. SGLT2 inhibition prevented the blood pressure increase in Sglt1-/- Akita mice, possibly due to additive glucosuric/diuretic effects. The data indicate that SGLT1 contributes to diabetic hyperfiltration and limits diabetic hypertension. Potential mechanisms include its role in glucose-driven upregulation of MD-NOS1 expression. This pathway may increase GFR to maintain volume balance when enhanced MD glucose delivery indicates upstream saturation of SGLTs and thus hyperreabsorption.
Collapse
Affiliation(s)
- Panai Song
- Division of Nephrology, Department of Medicine, University of California-San Diego , La Jolla, California.,Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Winnie Huang
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Akira Onishi
- Division of Nephrology, Department of Medicine, University of California-San Diego , La Jolla, California.,Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Rohit Patel
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Young Chul Kim
- Division of Nephrology, Department of Medicine, University of California-San Diego , La Jolla, California.,Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Charlotte van Ginkel
- Division of Nephrology, Department of Medicine, University of California-San Diego , La Jolla, California.,Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Yiling Fu
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Brent Freeman
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Hermann Koepsell
- Institute for Anatomy and Cell Biology, University of Würzburg , Würzburg , Germany
| | - Scott Thomson
- Division of Nephrology, Department of Medicine, University of California-San Diego , La Jolla, California.,Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine , Tampa, Florida
| | - Volker Vallon
- Division of Nephrology, Department of Medicine, University of California-San Diego , La Jolla, California.,Veterans Affairs San Diego Healthcare System, San Diego, California.,Department of Pharmacology, University of California-San Diego , La Jolla, California
| |
Collapse
|
47
|
Abstract
PURPOSE OF REVIEW To maintain electrolyte homeostasis, the kidneys reabsorb more than 99% of the filtered Na under physiological conditions, resulting in less than 1% of the filtered Na excreted in urine. In contrast, due to distal tubular secretion, urinary K output may exceed filtered load. This review focuses on a relatively new methodology for investigating renal epithelial transport, computational modelling and highlights recent insights regarding renal Na and K transport and O2 consumption under pathophysiological conditions, with a focus on nephrectomy. RECENT FINDINGS Recent modelling studies investigated the extent to which the adaptive response to nephrectomy, which includes elevation in single-nephron glomerular filtration rate and tubular transport capacity, may achieve balance but increases O2 consumption per nephron. Simulation results pointed to potential mechanisms in a hemi-nephrectomized rat that may attenuate the natriuresis response under K load, or that may augment the natriuretic, diuretic and kaliuretic effects of sodium glucose cotransporter 2 inhibition. SUMMARY Computational models provide a systemic approach for investigating system perturbations, such as those induced by drug administration or genetic alterations. Thus, computational models can be a great asset in data interpretation concerning (but not limited to) renal tubular transport and metabolism.
Collapse
Affiliation(s)
- Anita T Layton
- Department of Mathematics.,Department of Biomedical Engineering.,Department of Medicine, Duke University, Durham, North Carolina.,Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Volker Vallon
- Department of Medicine.,Department of Pharmacology, University of California, San Diego, La Jolla.,San Diego Veterans Affairs Healthcare System, San Diego, California, USA
| |
Collapse
|
48
|
Zhang J, Wei J, Jiang S, Xu L, Wang L, Cheng F, Buggs J, Koepsell H, Vallon V, Liu R. Macula Densa SGLT1-NOS1-Tubuloglomerular Feedback Pathway, a New Mechanism for Glomerular Hyperfiltration during Hyperglycemia. J Am Soc Nephrol 2019; 30:578-593. [PMID: 30867247 DOI: 10.1681/asn.2018080844] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 01/27/2019] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Glomerular hyperfiltration is common in early diabetes and is considered a risk factor for later diabetic nephropathy. We propose that sodium-glucose cotransporter 1 (SGLT1) senses increases in luminal glucose at the macula densa, enhancing generation of neuronal nitric oxide synthase 1 (NOS1)-dependent nitric oxide (NO) in the macula densa and blunting the tubuloglomerular feedback (TGF) response, thereby promoting the rise in GFR. METHODS We used microperfusion, micropuncture, and renal clearance of FITC-inulin to examine the effects of tubular glucose on NO generation at the macula densa, TGF, and GFR in wild-type and macula densa-specific NOS1 knockout mice. RESULTS Acute intravenous injection of glucose induced hyperglycemia and glucosuria with increased GFR in mice. We found that tubular glucose blunts the TGF response in vivo and in vitro and stimulates NO generation at the macula densa. We also showed that SGLT1 is expressed at the macula densa; in the presence of tubular glucose, SGLT1 inhibits TGF and NO generation, but this action is blocked when the SGLT1 inhibitor KGA-2727 is present. In addition, we demonstrated that glucose increases NOS1 expression and NOS1 phosphorylation at Ser1417 in mouse renal cortex and cultured human kidney tissue. In macula densa-specific NOS1 knockout mice, glucose had no effect on NO generation, TGF, and GFR. CONCLUSIONS We identified a novel mechanism of acute hyperglycemia-induced hyperfiltration wherein increases in luminal glucose at the macula densa upregulate the expression and activity of NOS1 via SGLT1, blunting the TGF response and promoting glomerular hyperfiltration.
Collapse
Affiliation(s)
- Jie Zhang
- Department of Molecular Pharmacology and Physiology, College of Medicine,
| | - Jin Wei
- Department of Molecular Pharmacology and Physiology, College of Medicine
| | - Shan Jiang
- Department of Molecular Pharmacology and Physiology, College of Medicine
| | - Lan Xu
- Department of Biostatistics, College of Public Health, and
| | - Lei Wang
- Department of Molecular Pharmacology and Physiology, College of Medicine
| | - Feng Cheng
- Department of Pharmaceutical Science, College of Pharmacy, University of South Florida, Tampa, Florida
| | - Jacentha Buggs
- Advanced Organ Disease & Transplantation Institute, Tampa General Hospital, Tampa, Florida
| | - Hermann Koepsell
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany; and
| | - Volker Vallon
- Division of Nephrology and Hypertension, Department of Medicine, University of California, San Diego, La Jolla, California
| | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology, College of Medicine
| |
Collapse
|
49
|
Novikov A, Fu Y, Huang W, Freeman B, Patel R, van Ginkel C, Koepsell H, Busslinger M, Onishi A, Nespoux J, Vallon V. SGLT2 inhibition and renal urate excretion: role of luminal glucose, GLUT9, and URAT1. Am J Physiol Renal Physiol 2018; 316:F173-F185. [PMID: 30427222 DOI: 10.1152/ajprenal.00462.2018] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Inhibitors of the Na+-glucose cotransporter SGLT2 enhance urinary glucose and urate excretion and lower plasma urate levels. The mechanisms remain unclear, but a role for enhanced glucose in the tubular fluid, which may interact with tubular urate transporters, such as the glucose transporter GLUT9 or the urate transporter URAT1, has been proposed. Studies were performed in nondiabetic mice treated with the SGLT2 inhibitor canagliflozin and in gene-targeted mice lacking the urate transporter Glut9 in the tubule or in mice with whole body knockout of Sglt2, Sglt1, or Urat1. Renal urate handling was assessed by analysis of urate in spontaneous plasma and urine samples and normalization to creatinine concentrations or by renal clearance studies with assessment of glomerular filtration rate by FITC-sinistrin. The experiments confirmed the contribution of URAT1 and GLUT9 to renal urate reabsorption, showing a greater contribution of the latter and additive effects. Genetic and pharmacological inhibition of SGLT2 enhanced fractional renal urate excretion (FE-urate), indicating that a direct effect of the SGLT2 inhibitor on urate transporters is not absolutely necessary. Consistent with a proposed role of increased luminal glucose delivery, the absence of Sglt1, which by itself had no effect on FE-urate, enhanced the glycosuric and uricosuric effects of the SGLT2 inhibitor. The SGLT2 inhibitor enhanced renal mRNA expression of Glut9 in wild-type mice, but tubular GLUT9 seemed dispensable for the increase in FE-urate in response to canagliflozin. First evidence is presented that URAT1 is required for the acute uricosuric effect of the SGLT2 inhibitor in mice.
Collapse
Affiliation(s)
- Aleksandra Novikov
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Yiling Fu
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Winnie Huang
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Brent Freeman
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Rohit Patel
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Charlotte van Ginkel
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Hermann Koepsell
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University of Würzburg , Würzburg , Germany
| | | | - Akira Onishi
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Josselin Nespoux
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System , San Diego, California
| | - Volker Vallon
- Department of Medicine, University of California San Diego and Veterans Affairs San Diego Healthcare System , San Diego, California.,Department of Pharmacology, University of California San Diego , La Jolla, California
| |
Collapse
|
50
|
Abstract
Sodium-glucose cotransporters SGLT1 (encoded by SGLT1, also known as SLC5A1) and SGLT2 (encoded by SGLT2, also known as SLC5A2) are important mediators of epithelial glucose transport. While SGLT1 accounts for most of the dietary glucose uptake in the intestine, SGLT2 is responsible for the majority of glucose reuptake in the tubular system of the kidney, with SGLT1 reabsorbing the remainder of the filtered glucose. As a consequence, mutations in the SLC5A1 gene cause glucose/galactose malabsorption, whereas mutations in SLC5A2 are associated with glucosuria. Since the cloning of SGLT1 more than 30 years ago, big strides have been made in our understanding of these transporters and their suitability as drug targets. Phlorizin, a naturally occurring competitive inhibitor of SGLT1 and SGLT2, provided the first insights into potential efficacy, but its use was hampered by intestinal side effects and a short half-life. Nevertheless, it was a starting point for the development of specific inhibitors of SGLT1 and SGLT2, as well as dual SGLT1/2 inhibitors. Since the approval of the first SGLT2 inhibitor in 2013 by the US Food and Drug Administration, SGLT2 inhibitors have become a new mainstay in the treatment of type 2 diabetes mellitus. They also have beneficial effects on the cardiovascular system (including heart failure) and the kidney. This review focuses on the rationale for the development of individual SGLT2 and SGLT1 inhibitors, as well as dual SGLT1/2 inhibition, including, but not limited to, aspects of genetics, genetically modified mouse models, mathematical modelling and general considerations of drug discovery in the field of metabolism.
Collapse
Affiliation(s)
- Timo Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, 12901 Bruce B. Downs Blvd, Tampa, FL, 33592, USA.
| | - Volker Vallon
- Department of Medicine, Division of Nephrology and Hypertension, University of California San Diego, 3350 La Jolla Village Drive, San Diego, CA, 92161, USA.
- Department of Pharmacology, University of California San Diego, La Jolla, CA, USA.
- VA San Diego Healthcare System, San Diego California, San Diego, CA, USA.
| |
Collapse
|