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Gong Y, Bai X, Zhang D, Yang X, Qin Z, Yang Y, Zhou Y, Meng J, Liu X. Effect of DPP-4i inhibitors on renal function in patients with type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials. Lipids Health Dis 2024; 23:157. [PMID: 38796440 PMCID: PMC11128128 DOI: 10.1186/s12944-024-02132-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 05/06/2024] [Indexed: 05/28/2024] Open
Abstract
AIMS About 20-40% patients with type 2 diabetes mellitus (T2DM) had an increased risk of developing diabetic nephropathy (DN). Dipeptidyl peptidase-4 inhibitors (DPP-4i) were recommended for treatment of T2DM, while the impact of DPP-4i on renal function remained unclear. This study aimed to explore the effect of DPP-4i on renal parameter of estimated glomerular filtration rate (eGFR) and albumin-to-creatinine ratio (ACR) in T2DM. METHODS A systematic search was performed across PubMed, Embase and Cochrane Library. A fixed or random-effects model was used for quantitative synthesis according to the heterogeneity, which was assessed with I2 index. Sensitivity analysis and publication bias were performed with standard methods, respectively. RESULTS A total of 17 randomized controlled trials were identified. Administration of DPP-4i produced no significant effect on eGFR (WMD, -0.92 mL/min/1.73m2, 95% CI, -2.04 to 0.19) in diabetic condition. DPP-4i produced a favorable effect on attenuating ACR (WMD, -2.76 mg/g, 95% CI, -5.23 to -0.29) in patients with T2DM. The pooled estimate was stable based on the sensitivity test. No publication bias was observed according to Begg's and Egger's tests. CONCLUSIONS Treatment with DPP-4i preserved the renal parameter of eGFR in diabetic condition. Available evidences suggested that administration of DPP-4i produced a favorable effect on attenuating ACR in patients with T2DM. INTERNATIONAL PROSPECTIVE REGISTER FOR SYSTEMATIC REVIEW (PROSPERO) NUMBER: CRD.42020144642.
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Affiliation(s)
- Yong Gong
- Department of Nephrology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xueyan Bai
- Department of Hemotology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Donglei Zhang
- Department of Hemotology, Zhongnan Hospital, Wuhan University, Wuhan, Hubei, China
| | - Xingsheng Yang
- Department of Cardiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Zheng Qin
- Department of Cardiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yu Yang
- Department of Cardiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yilun Zhou
- Department of Nephrology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
| | - Jie Meng
- Department of Pathology, Beijing TongRen Hospital, Capital Medical University, Beijing, China.
| | - Xin Liu
- Department of Pharmacy, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
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2
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Hu H, Liang W, Ding G. Ion homeostasis in diabetic kidney disease. Trends Endocrinol Metab 2024; 35:142-150. [PMID: 37880052 DOI: 10.1016/j.tem.2023.09.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/29/2023] [Accepted: 09/29/2023] [Indexed: 10/27/2023]
Abstract
The complications of type 2 diabetes are a major global public health problem with high incidence and mortality, affecting almost all individuals with diabetes worldwide. Diabetic kidney disease (DKD) is one such primary complication and has become a leading cause of end-stage renal disease in patients with diabetes. Progression from diabetes to DKD is a complex process typically involving multiple mechanisms. Recent remarkable clinical benefits of sodium-glucose cotransporter 2 (SGLT2) inhibitors in diabetes and DKD highlight the critical impact of renal ion homeostasis on disease progression. This review comprehensively examines the impact of ion homeostasis on the transition from diabetes to DKD, outlining possible therapeutic interventions and addressing the ongoing challenges in this rapidly developing field.
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Affiliation(s)
- Hongtu Hu
- Division of Nephrology, Renmin Hospital of Wuhan University, 238 Jiefang Rd, Wuhan, Hubei 430060, China; Key Clinical Research Center of Kidney Disease, 238 Jiefang Rd, Wuhan, Hubei 430060, China
| | - Wei Liang
- Division of Nephrology, Renmin Hospital of Wuhan University, 238 Jiefang Rd, Wuhan, Hubei 430060, China; Key Clinical Research Center of Kidney Disease, 238 Jiefang Rd, Wuhan, Hubei 430060, China.
| | - Guohua Ding
- Division of Nephrology, Renmin Hospital of Wuhan University, 238 Jiefang Rd, Wuhan, Hubei 430060, China; Key Clinical Research Center of Kidney Disease, 238 Jiefang Rd, Wuhan, Hubei 430060, China.
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3
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Guo H, Bechtel-Walz W. The Interplay of Autophagy and Oxidative Stress in the Kidney: What Do We Know? Nephron Clin Pract 2023; 147:627-642. [PMID: 37442108 DOI: 10.1159/000531290] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 05/19/2023] [Indexed: 07/15/2023] Open
Abstract
BACKGROUND Autophagy, as an indispensable metabolism, plays pivotal roles in maintaining intracellular homeostasis. Nutritional stress, amino acid deficiency, oxidative stress, and hypoxia can trigger its initiation. Oxidative stress in the kidney activates essential signal molecules, like mammalian target of rapamycin (mTOR), adenosine monophosphate-activated protein kinase (AMPK), and silent mating-type information regulation 2 homolog-1 (SIRT1), to stimulate autophagy, ultimately leading to degradation of intracellular oxidative substances and damaged organelles. Growing evidence suggests that autophagy protects the kidney from oxidative stress during acute ischemic kidney injury, chronic kidney disease, and even aging. SUMMARY This review emphasizes the cross talk between reactive oxygen species (ROS) signaling pathways and autophagy during renal homeostasis and chronic kidney disease according to the current latest research and provides therapeutic targets during kidney disorders by adjusting autophagy and suppressing oxidative stress. KEY MESSAGES ROS arise through an imbalance of oxidation and antioxidant defense mechanisms, leading to impaired cellular and organ function. Targeting the overproduction of ROS and reactive nitrogen species, reducing the antioxidant enzyme activity and the recovery of the prooxidative-antioxidative balance provide novel therapeutic regimens to contribute to recovery in acute and chronic renal failure. Although, in recent years, great progress has been made in understanding the molecular mechanisms of oxidative stress and autophagy in acute and chronic renal failure, the focus on clinical therapies is still in its infancy. The growing number of studies on the interactive mechanisms of oxidative stress-mediated autophagy will be of great importance for the future treatment and prevention of kidney diseases.
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Affiliation(s)
- Haihua Guo
- Renal Division, Department of Medicine, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Wibke Bechtel-Walz
- Renal Division, Department of Medicine, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
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Savedchuk S, Phachu D, Shankar M, Sparks MA, Harrison-Bernard LM. Targeting Glomerular Hemodynamics for Kidney Protection. ADVANCES IN KIDNEY DISEASE AND HEALTH 2023; 30:71-84. [PMID: 36868736 DOI: 10.1053/j.akdh.2022.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 12/14/2022] [Indexed: 03/05/2023]
Abstract
The kidney microcirculation is a unique structure as it is composed to 2 capillary beds in series: the glomerular and peritubular capillaries. The glomerular capillary bed is a high-pressure capillary bed, having a 60 mm Hg to 40 mm Hg pressure gradient, capable of producing an ultrafiltrate of plasma quantified as the glomerular filtration rate (GFR), thereby allowing for waste products to be removed and establishing sodium/volume homeostasis. Entering the glomerulus is the afferent arteriole, and the exiting one is the efferent arteriole. The concerted resistance of each of these arterioles is what is known as glomerular hemodynamics and is responsible for increasing or decreasing GFR and renal blood flow. Glomerular hemodynamics play an important role in how homeostasis is achieved. Minute-to-minute fluctuations in the GFR are achieved by constant sensing of distal delivery of sodium and chloride in the specialized cells called macula densa leading to upstream alternation in afferent arteriole resistance altering the pressure gradient for filtration. Specifically, 2 classes of medications (sodium glucose cotransporter-2 inhibitors and renin-angiotensin system blockers) have shown to be effective in long-term kidney health by altering glomerular hemodynamics. This review will discuss how tubuloglomerular feedback is achieved, and how different disease states and pharmacologic agents alter glomerular hemodynamics.
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Affiliation(s)
- Solomiia Savedchuk
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, NC
| | - Deep Phachu
- Division of Nephrology, University of Connecticut, Farmington, CT
| | - Mythri Shankar
- Department of Nephrology, Institute of Nephrourology, Bengaluru, India
| | - Matthew A Sparks
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, NC; Renal Section, Durham VA Health Care System, Durham, NC
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5
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Diabetes Mellitus and the Kidneys. Vet Clin North Am Small Anim Pract 2023; 53:565-580. [PMID: 36854633 DOI: 10.1016/j.cvsm.2023.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
The pathomechanisms implicated in diabetic kidney disease in people are present in dogs and cats and, in theory, could lead to renal complications in companion animals with long-standing diabetes mellitus. However, these renal complications develop during a long period, and there is little to no clinical evidence that they could lead to chronic kidney disease in companion animals.
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6
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Solomon J, Festa MC, Chatzizisis YS, Samanta R, Suri RS, Mavrakanas TA. Sodium-glucose co-transporter 2 inhibitors in patients with chronic kidney disease. Pharmacol Ther 2023; 242:108330. [PMID: 36513134 DOI: 10.1016/j.pharmthera.2022.108330] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 12/05/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022]
Abstract
Diabetes drives an increasing burden of cardiovascular and renal disease worldwide, motivating the search for new hypoglycemic agents that confer cardiac and renal protective effects. Although initially developed as hypoglycemic agents, sodium-glucose co-transporter 2 (SGLT-2) inhibitors have since been studied in patients with and without diabetes for the management of heart failure and chronic kidney disease. A growing body of evidence supports the efficacy and safety of SGLT-2 inhibitors in patients with chronic kidney disease (CKD), based on complex mechanisms of action that extend far beyond glucosuria and that confer beneficial effects on cardiovascular and renal hemodynamics, fibrosis, inflammation, and end-organ protection. This review focuses on the pharmacology and pathophysiology of SGLT-2 inhibitors in patients with CKD, as well as their cardiovascular and renal effects in this population. We are focusing on the five agents that have been tested in cardiovascular outcome trials and that have been approved either in Europe or in North America: empagliflozin, dapagliflozin, canagliflozin, ertugliglozin, and sotagliflozin.
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Affiliation(s)
- Joshua Solomon
- Division of Internal Medicine, Department of Medicine, McGill University, Montreal, QC, Canada
| | - Maria Carolina Festa
- Division of Internal Medicine, Department of Medicine, McGill University, Montreal, QC, Canada
| | - Yiannis S Chatzizisis
- Division of Cardiovascular Medicine, College of Medicine, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Ratna Samanta
- Division of Nephrology, Department of Medicine, McGill University Health Center, Montreal, QC, Canada
| | - Rita S Suri
- Division of Nephrology, Department of Medicine, McGill University Health Center, Montreal, QC, Canada; Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Thomas A Mavrakanas
- Division of Nephrology, Department of Medicine, McGill University Health Center, Montreal, QC, Canada; Research Institute of the McGill University Health Center, Montreal, QC, Canada.
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7
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An Overview of the Cardiorenal Protective Mechanisms of SGLT2 Inhibitors. Int J Mol Sci 2022; 23:ijms23073651. [PMID: 35409011 PMCID: PMC8998569 DOI: 10.3390/ijms23073651] [Citation(s) in RCA: 66] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/17/2022] [Accepted: 03/24/2022] [Indexed: 02/04/2023] Open
Abstract
Sodium-glucose co-transporter 2 (SGLT2) inhibitors block glucose reabsorption in the renal proximal tubule, an insulin-independent mechanism that plays a critical role in glycemic regulation in diabetes. In addition to their glucose-lowering effects, SGLT2 inhibitors prevent both renal damage and the onset of chronic kidney disease and cardiovascular events, in particular heart failure with both reduced and preserved ejection fraction. These unexpected benefits prompted changes in treatment guidelines and scientific interest in the underlying mechanisms. Aside from the target effects of SGLT2 inhibition, a wide spectrum of beneficial actions is described for the kidney and the heart, even though the cardiac tissue does not express SGLT2 channels. Correction of cardiorenal risk factors, metabolic adjustments ameliorating myocardial substrate utilization, and optimization of ventricular loading conditions through effects on diuresis, natriuresis, and vascular function appear to be the main underlying mechanisms for the observed cardiorenal protection. Additional clinical advantages associated with using SGLT2 inhibitors are antifibrotic effects due to correction of inflammation and oxidative stress, modulation of mitochondrial function, and autophagy. Much research is required to understand the numerous and complex pathways involved in SGLT2 inhibition. This review summarizes the current known mechanisms of SGLT2-mediated cardiorenal protection.
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8
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Yang Y, Xu G. Update on Pathogenesis of Glomerular Hyperfiltration in Early Diabetic Kidney Disease. Front Endocrinol (Lausanne) 2022; 13:872918. [PMID: 35663316 PMCID: PMC9161673 DOI: 10.3389/fendo.2022.872918] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 04/11/2022] [Indexed: 11/13/2022] Open
Abstract
In the existing stages of diabetic kidney disease (DKD), the first stage of DKD is called the preclinical stage, characterized by glomerular hyperfiltration, an abnormally elevated glomerular filtration rate. Glomerular hyperfiltration is an independent risk factor for accelerated deterioration of renal function and progression of nephropathy, which is associated with a high risk for metabolic and cardiovascular disease. It is imperative to understand hyperfiltration and identify potential treatments to delay DKD progress. This paper summarizes the current mechanisms of hyperfiltration in early DKD. We pay close attention to the effect of glucose reabsorption mediated by sodium-glucose cotransporters and renal growth on hyperfiltration in DKD patients, as well as the mechanisms of nitric oxide and adenosine actions on renal afferent arterioles via tubuloglomerular feedback. Furthermore, we also focus on the contribution of the atrial natriuretic peptide, cyclooxygenase, renin-angiotensin-aldosterone system, and endothelin on hyperfiltration. Proposing potential treatments based on these mechanisms may offer new therapeutic opportunities to reduce the renal burden in this population.
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9
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Ahmad AA, Draves SO, Rosca M. Mitochondria in Diabetic Kidney Disease. Cells 2021; 10:cells10112945. [PMID: 34831168 PMCID: PMC8616075 DOI: 10.3390/cells10112945] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/26/2021] [Accepted: 10/28/2021] [Indexed: 12/11/2022] Open
Abstract
Diabetic kidney disease (DKD) is the leading cause of end stage renal disease (ESRD) in the USA. The pathogenesis of DKD is multifactorial and involves activation of multiple signaling pathways with merging outcomes including thickening of the basement membrane, podocyte loss, mesangial expansion, tubular atrophy, and interstitial inflammation and fibrosis. The glomerulo-tubular balance and tubule-glomerular feedback support an increased glomerular filtration and tubular reabsorption, with the latter relying heavily on ATP and increasing the energy demand. There is evidence that alterations in mitochondrial bioenergetics in kidney cells lead to these pathologic changes and contribute to the progression of DKD towards ESRD. This review will focus on the dialogue between alterations in bioenergetics in glomerular and tubular cells and its role in the development of DKD. Alterations in energy substrate selection, electron transport chain, ATP generation, oxidative stress, redox status, protein posttranslational modifications, mitochondrial dynamics, and quality control will be discussed. Understanding the role of bioenergetics in the progression of diabetic DKD may provide novel therapeutic approaches to delay its progression to ESRD.
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10
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DeFronzo RA, Abdul-Ghani M. Sodium-Glucose Cotransporter 2 Inhibitors and the Kidney. Diabetes Spectr 2021; 34:225-234. [PMID: 34511848 PMCID: PMC8387612 DOI: 10.2337/ds20-0071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Diabetic kidney disease (DKD) accounts for about half of individuals entering end-stage renal disease programs. Patients with DKD frequently have associated microvascular complications and are at very high risk for developing macrovascular complications. Comprehensive treatment involves slowing or preventing the decline in glomerular filtration rate (GFR) and preventing macrovascular and further microvascular complications. Maintaining an A1C <6.5% represents primary prevention; in established DKD, tight blood pressure control is essential. ACE inhibitors/angiotensin receptor blockers (ARBs) and sodium-glucose cotransporter 2 (SGLT2) inhibitors can be used in combination to slow the rate of decline in GFR. This article reviews the general approach to DKD treatment and summarizes renal outcomes in four cardiovascular outcomes trials of SGLT2 inhibitors. Together, these trials provide conclusive evidence that SGLT2 inhibitors, added to an ACE inhibitor or ARB, slow the progression of DKD.
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11
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Pathophysiology of diabetic kidney disease: impact of SGLT2 inhibitors. Nat Rev Nephrol 2021; 17:319-334. [PMID: 33547417 DOI: 10.1038/s41581-021-00393-8] [Citation(s) in RCA: 230] [Impact Index Per Article: 76.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2021] [Indexed: 01/30/2023]
Abstract
Diabetic kidney disease is the leading cause of kidney failure worldwide; in the USA, it accounts for over 50% of individuals entering dialysis or transplant programmes. Unlike other complications of diabetes, the prevalence of diabetic kidney disease has failed to decline over the past 30 years. Hyperglycaemia is the primary aetiological factor responsible for the development of diabetic kidney disease. Once hyperglycaemia becomes established, multiple pathophysiological disturbances, including hypertension, altered tubuloglomerular feedback, renal hypoxia, lipotoxicity, podocyte injury, inflammation, mitochondrial dysfunction, impaired autophagy and increased activity of the sodium-hydrogen exchanger, contribute to progressive glomerular sclerosis and the decline in glomerular filtration rate. The quantitative contribution of each of these abnormalities to the progression of diabetic kidney disease, as well as their role in type 1 and type 2 diabetes mellitus, remains to be determined. Sodium-glucose co-transporter 2 (SGLT2) inhibitors have a beneficial impact on many of these pathophysiological abnormalities; however, as several pathophysiological disturbances contribute to the onset and progression of diabetic kidney disease, multiple agents used in combination will likely be required to slow the progression of disease effectively.
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12
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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] [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.
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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
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13
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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: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [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.
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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
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14
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Tubular effects of sodium-glucose cotransporter 2 inhibitors: intended and unintended consequences. Curr Opin Nephrol Hypertens 2020; 29:523-530. [PMID: 32701600 DOI: 10.1097/mnh.0000000000000632] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
PURPOSE OF REVIEW Sodium-glucose cotransporter 2 (SGLT2) inhibitors are antihyperglycemic drugs that act by inhibiting renal sodium-glucose cotransport. Here we present new insights into 'off target', or indirect, effects of SGLT2 inhibitors. RECENT FINDINGS SGLT2 inhibition causes an acute increase in urinary glucose excretion. In addition to lowering blood glucose, there are several other effects that contribute to the overall beneficial renal and cardiovascular effects. Reabsorption of about 66% of sodium is accomplished in the proximal tubule and dependent on the sodium-hydrogen exchanger isoform 3 (NHE3). SGLT2 colocalizes with NHE3, and high glucose levels reduce NHE3 activity. The proximal tubule is also responsible for the majority of phosphate (Pi) reabsorption. SGLT2 inhibition is associated with increases in plasma Pi, fibroblast growth factor 23 and parathyroid hormone levels in nondiabetics and type 2 diabetes mellitus. Studies in humans identified a urate-lowering effect by SGLT2 inhibition which is possibly mediated by urate transporter 1 (URAT1) and/or glucose transporter member 9 in the proximal tubule. Of note, magnesium levels were also found to increase under SGLT2 inhibition, an effect that was preserved in nondiabetic patients with hypomagnesemia. SUMMARY Cardiorenal effects of SGLT2 inhibition might involve, in addition to direct effects on glucose homeostasis, effects on NHE3, phosphate, urate, and magnesium homeostasis.
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Abstract
PURPOSE OF REVIEW SGLT2 inhibitors are a new class of antihyperglycemic drugs that protect kidneys and hearts of type 2 diabetic (T2DM) patients with preserved kidney function from failing. Here we discuss new insights on renal protection. RECENT FINDINGS Also in T2DM patients with CKD, SGLT2 inhibition causes an immediate functional reduction in glomerular filtration rate (GFR) and reduces blood pressure and preserves kidney and heart function in the long-term, despite a lesser antihyperglycemic effect. According to modeling studies, the GFR reduction reduces the tubular transport work and metabolic demand, thereby improving renal cortical oxygenation. In humans, the latter is linked to protection from CKD. Urine metabolomics in T2DM patients suggested improved renal mitochondrial function in response to SGLT2 inhibition, and experimental studies indicated improved tubular autophagy. Modeling studies predicted that also in diabetic CKD, SGLT2 inhibition is natriuretic and potentially stimulates erythropoiesis by mimicking systemic hypoxia in the kidney. Meta-analyses indicated that SGLT2 inhibition also reduces risk and severity of acute kidney injury in T2DM patients. Studies in nondiabetic mice implied inhibition of the renal urate transporter URAT1 in the uricosuric effect of SGLT2 inhibition. SUMMARY Renoprotection of SGLT2 inhibition involves blood glucose-dependent and independent effects and extends to CKD.
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Vallon V, Thomson SC. The tubular hypothesis of nephron filtration and diabetic kidney disease. Nat Rev Nephrol 2020; 16:317-336. [PMID: 32152499 DOI: 10.1038/s41581-020-0256-y] [Citation(s) in RCA: 213] [Impact Index Per Article: 53.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2020] [Indexed: 02/08/2023]
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.
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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
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17
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Mitochondrial dysfunction in diabetic kidney disease. Clin Chim Acta 2019; 496:108-116. [PMID: 31276635 DOI: 10.1016/j.cca.2019.07.005] [Citation(s) in RCA: 131] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 06/27/2019] [Accepted: 07/01/2019] [Indexed: 12/26/2022]
Abstract
Although diabetic kidney disease (DKD) is the most common cause of end-stage kidney disease worldwide, the pathogenic mechanisms are poorly understood. There is increasing evidence that mitochondrial dysfunction contributes to the development and progression of DKD. Because the kidney is the organ with the second highest oxygen consumption in our body, it is distinctly sensitive to mitochondrial dysfunction. Mitochondrial dysfunction contributes to the progression of chronic kidney disease irrespective of underlying cause. More importantly, high plasma glucose directly damages renal tubular cells, resulting in a wide range of metabolic and cellular dysfunction. Overproduction of reactive oxygen species (ROS), activation of apoptotic pathway, and defective mitophagy are interlinked mechanisms that play pivotal roles in the progression of DKD. Although renal tubular cells have the highest mitochondrial content, podocytes, mesangial cells, and glomerular endothelial cells may all be affected by diabetes-induced mitochondrial injury. Urinary mitochondrial DNA (mtDNA) is readily detectable and may serve as a marker of mitochondrial damage in DKD. Unfortunately, pharmacologic modulation of mitochondrial dysfunction for the treatment of DKD is still in its infancy. Nonetheless, understanding the pathobiology of mitochondrial dysfunction in DKD would facilitate the development of novel therapeutic strategies.
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18
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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: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [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.
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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
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19
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Persson P, Fasching A, Palm F. Acute intrarenal angiotensin (1-7) infusion decreases diabetes-induced glomerular hyperfiltration but increases kidney oxygen consumption in the rat. Acta Physiol (Oxf) 2019; 226:e13254. [PMID: 30635985 DOI: 10.1111/apha.13254] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 11/30/2022]
Abstract
AIM Common kidney alterations early after the onset of insulinopenic diabetes include glomerular hyperfiltration, increased oxygen consumption and tissue hypoxia. Increased activity of the renin-angiotensin-aldosterone system (RAAS) has been implicated in most of these early alterations. The RAAS peptide angiotensin (1-7) has the potential to modulate RAAS-mediated alterations in kidney function. Thus, the aim of the present study was to determine the acute effects of angiotensin (1-7) in the kidney of insulinopenic type 1 diabetic rat and the results compared to that of normoglycaemic controls. METHODS Renal haemodynamics and oxygen homeostasis were measured 3 weeks after administration of streptozotocin before and after acute intrarenal infusion of angiotensin (1-7) at a dose of 400 ng min-1 . RESULTS Arterial pressure and renal blood flow were similar between groups and not affected by exogenous angiotensin (1-7). Diabetics presented with glomerular hyperfiltration, increased urinary sodium excretion and elevated kidney oxygen consumption. Angiotensin (1-7) infusion normalized glomerular filtration, increased urinary sodium excretion, decreased proximal tubular reabsorption, and elevated kidney oxygen consumption even further. The latter resulting in tubular electrolyte transport inefficiency. Angiotensin (1-7) did not affect tissue oxygen tension and had no significant effects in controls on any of the measured parameters. CONCLUSION Diabetes results in increased responsiveness to elevated levels of angiotensin (1-7) which is manifested as inhibition of tubular sodium transport and normalization of glomerular filtration. Furthermore, elevated angiotensin (1-7) levels increase kidney oxygen consumption in the diabetic kidney even further which affects tubular electrolyte transport efficiency negatively.
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Affiliation(s)
- Patrik Persson
- Division of Integrative Physiology, Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | - Angelica Fasching
- Division of Integrative Physiology, Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | - Fredrik Palm
- Division of Integrative Physiology, Department of Medical Cell Biology Uppsala University Uppsala Sweden
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20
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Abstract
Globally, diabetes is the leading cause of chronic kidney disease and end-stage renal disease, which are major risk factors for cardiovascular disease and death. Despite this burden, the factors that precipitate the development and progression of diabetic kidney disease (DKD) remain to be fully elucidated. Mitochondrial dysfunction is associated with kidney disease in nondiabetic contexts, and increasing evidence suggests that dysfunctional renal mitochondria are pathological mediators of DKD. These complex organelles have a broad range of functions, including the generation of ATP. The kidneys are mitochondrially rich, highly metabolic organs that require vast amounts of ATP for their normal function. The delivery of metabolic substrates for ATP production, such as fatty acids and oxygen, is altered by diabetes. Changes in metabolic fuel sources in diabetes to meet ATP demands result in increased oxygen consumption, which contributes to renal hypoxia. Inherited factors including mutations in genes that impact mitochondrial function and/or substrate delivery may also be important risk factors for DKD. Hence, we postulate that the diabetic milieu and inherited factors that underlie abnormalities in mitochondrial function synergistically drive the development and progression of DKD.
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Affiliation(s)
- Josephine M Forbes
- Glycation and Diabetes Group, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia.,Mater Clinical School, School of Medicine, The University of Queensland, St Lucia, Queensland, Australia.,Departments of Medicine and Paediatrics, The University of Melbourne, Parkville, Victoria, Australia
| | - David R Thorburn
- Departments of Medicine and Paediatrics, The University of Melbourne, Parkville, Victoria, Australia.,Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
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21
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Fenton RA, Poulsen SB, de la Mora Chavez S, Soleimani M, Dominguez Rieg JA, Rieg T. Renal tubular NHE3 is required in the maintenance of water and sodium chloride homeostasis. Kidney Int 2017; 92:397-414. [PMID: 28385297 DOI: 10.1016/j.kint.2017.02.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 01/25/2017] [Accepted: 02/02/2017] [Indexed: 11/30/2022]
Abstract
The sodium/proton exchanger isoform 3 (NHE3) is expressed in the intestine and the kidney, where it facilitates sodium (re)absorption and proton secretion. The importance of NHE3 in the kidney for sodium chloride homeostasis, relative to the intestine, is unknown. Constitutive tubule-specific NHE3 knockout mice (NHE3loxloxCre) did not show significant differences compared to control mice in body weight, blood pH or bicarbonate and plasma sodium, potassium, or aldosterone levels. Fluid intake, urinary flow rate, urinary sodium/creatinine, and pH were significantly elevated in NHE3loxloxCre mice, while urine osmolality and GFR were significantly lower. Water deprivation revealed a small urinary concentrating defect in NHE3loxloxCre mice on a control diet, exaggerated on low sodium chloride. Ten days of low or high sodium chloride diet did not affect plasma sodium in control mice; however, NHE3loxloxCre mice were susceptible to low sodium chloride (about -4 mM) or high sodium chloride intake (about +2 mM) versus baseline, effects without differences in plasma aldosterone between groups. Blood pressure was significantly lower in NHE3loxloxCre mice and was sodium chloride sensitive. In control mice, the expression of the sodium/phosphate co-transporter Npt2c was sodium chloride sensitive. However, lack of tubular NHE3 blunted Npt2c expression. Alterations in the abundances of sodium/chloride cotransporter and its phosphorylation at threonine 58 as well as the abundances of the α-subunit of the epithelial sodium channel, and its cleaved form, were also apparent in NHE3loxloxCre mice. Thus, renal NHE3 is required to maintain blood pressure and steady-state plasma sodium levels when dietary sodium chloride intake is modified.
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Affiliation(s)
- Robert A Fenton
- InterPrET Center, Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Søren B Poulsen
- InterPrET Center, Department of Biomedicine, Aarhus University, Aarhus, Denmark; VA San Diego Healthcare System, San Diego, California, USA
| | | | - Manoocher Soleimani
- Department of Medicine, University of Cincinnati, Cincinnati, Ohio, USA; Research Services, Veterans Affairs Medical Center, Cincinnati, Ohio, USA
| | - Jessica A Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida, USA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida, USA.
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22
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Hallow KM, Gebremichael Y, Helmlinger G, Vallon V. Primary proximal tubule hyperreabsorption and impaired tubular transport counterregulation determine glomerular hyperfiltration in diabetes: a modeling analysis. Am J Physiol Renal Physiol 2017; 312:F819-F835. [PMID: 28148531 DOI: 10.1152/ajprenal.00497.2016] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 01/18/2017] [Accepted: 01/30/2017] [Indexed: 12/31/2022] Open
Abstract
Glomerular hypertension and hyperfiltration in early diabetes are associated with development and progression of diabetic kidney disease. The tubular hypothesis of diabetic hyperfiltration proposes that it is initiated by a primary increase in sodium (Na) reabsorption in the proximal tubule (PT) and the resulting tubuloglomerular feedback (TGF) response and lowering of Bowman space pressure (PBow). Here we utilized a mathematical model of the human kidney to investigate over acute and chronic timescales the mechanisms responsible for the magnitude of the hyperfiltration response. The model implicates that the primary hyperreabsorption of Na in the PT produces a Na imbalance that is only partially restored by the hyperfiltration induced by TGF and changes in PBow Thus secondary adaptations are needed to restore Na balance. This may include neurohumoral transport regulation and/or pressure-natriuresis (i.e., the decrease in Na reabsorption in response to increased renal perfusion pressure). We explored the role of each tubular segment in contributing to this compensation and the consequences of impairment in tubular compensation. The simulations indicate that impaired secondary downregulation of transport potentiated the rise in glomerular hypertension and hyperfiltration needed to restore Na balance at a given level of primary PT hyperreabsorption. Therefore, we propose for the first time that both the extent of primary PT hyperreabsorption and the degree of impairment of the distal tubular responsiveness to regulatory signals determine the level of glomerular hypertension and hyperfiltration in the diabetic kidney, thereby extending the tubule-centric concept of diabetic hyperfiltration and potential therapeutic approaches beyond the proximal tubule.
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Affiliation(s)
- K Melissa Hallow
- College of Engineering and College of Public Health, Department of Epidemiology and Biostatistics, University of Georgia, Athens, Georgia;
| | - Yeshitila Gebremichael
- College of Engineering and College of Public Health, Department of Epidemiology and Biostatistics, University of Georgia, Athens, Georgia
| | | | - Volker Vallon
- Division of Nephrology and Hypertension, Departments of Medicine and Pharmacology, University of California San Diego, La Jolla, California; and.,Veterans Affairs San Diego Healthcare System, San Diego, California
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23
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Oyarzún C, Garrido W, Alarcón S, Yáñez A, Sobrevia L, Quezada C, San Martín R. Adenosine contribution to normal renal physiology and chronic kidney disease. Mol Aspects Med 2017; 55:75-89. [PMID: 28109856 DOI: 10.1016/j.mam.2017.01.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 01/11/2017] [Accepted: 01/13/2017] [Indexed: 12/12/2022]
Abstract
Adenosine is a nucleoside that is particularly interesting to many scientific and clinical communities as it has important physiological and pathophysiological roles in the kidney. The distribution of adenosine receptors has only recently been elucidated; therefore it is likely that more biological roles of this nucleoside will be unveiled in the near future. Since the discovery of the involvement of adenosine in renal vasoconstriction and regulation of local renin production, further evidence has shown that adenosine signaling is also involved in the tubuloglomerular feedback mechanism, sodium reabsorption and the adaptive response to acute insults, such as ischemia. However, the most interesting finding was the increased adenosine levels in chronic kidney diseases such as diabetic nephropathy and also in non-diabetic animal models of renal fibrosis. When adenosine is chronically increased its signaling via the adenosine receptors may change, switching to a state that induces renal damage and produces phenotypic changes in resident cells. This review discusses the physiological and pathophysiological roles of adenosine and pays special attention to the mechanisms associated with switching homeostatic nucleoside levels to increased adenosine production in kidneys affected by CKD.
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Affiliation(s)
- Carlos Oyarzún
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Wallys Garrido
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Sebastián Alarcón
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Alejandro Yáñez
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain; University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston QLD 4029, Queensland, Australia
| | - Claudia Quezada
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Rody San Martín
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile.
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Heerspink HJL, Perkins BA, Fitchett DH, Husain M, Cherney DZI. Sodium Glucose Cotransporter 2 Inhibitors in the Treatment of Diabetes Mellitus: Cardiovascular and Kidney Effects, Potential Mechanisms, and Clinical Applications. Circulation 2016; 134:752-72. [PMID: 27470878 DOI: 10.1161/circulationaha.116.021887] [Citation(s) in RCA: 839] [Impact Index Per Article: 104.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Sodium-glucose cotransporter-2 (SGLT2) inhibitors, including empagliflozin, dapagliflozin, and canagliflozin, are now widely approved antihyperglycemic therapies. Because of their unique glycosuric mechanism, SGLT2 inhibitors also reduce weight. Perhaps more important are the osmotic diuretic and natriuretic effects contributing to plasma volume contraction, and decreases in systolic and diastolic blood pressures by 4 to 6 and 1 to 2 mm Hg, respectively, which may underlie cardiovascular and kidney benefits. SGLT2 inhibition also is associated with an acute, dose-dependent reduction in estimated glomerular filtration rate by ≈5 mL·min(-1)·1.73 m(-2) and ≈30% to 40% reduction in albuminuria. These effects mirror preclinical observations suggesting that proximal tubular natriuresis activates renal tubuloglomerular feedback through increased macula densa sodium and chloride delivery, leading to afferent vasoconstriction. On the basis of reduced glomerular filtration, glycosuric and weight loss effects are attenuated in patients with chronic kidney disease (estimated glomerular filtration rate <60 mL·min(-1)·1.73 m(-2)). In contrast, blood pressure lowering, estimated glomerular filtration rate, and albuminuric effects are preserved, and perhaps exaggerated in chronic kidney disease. With regard to long-term clinical outcomes, the EMPA-REG OUTCOME trial (Empagliflozin, Cardiovascular Outcomes, and Mortality in Type 2 Diabetes) in patients with type 2 diabetes mellitus and established cardiovascular disease randomly assigned to empagliflozin versus placebo reported a 14% reduction in the primary composite outcome of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, and >30% reductions in cardiovascular mortality, overall mortality, and heart failure hospitalizations associated with empagliflozin, even though, by design, the hemoglobin A1c difference between the randomized groups was marginal. Aside from an increased risk of mycotic genital infections, empagliflozin-treated patients had fewer serious adverse events, including a lower risk of acute kidney injury. In light of the EMPA-REG OUTCOME results, some diabetes clinical practice guidelines now recommend that SGLT2 inhibitors with proven cardiovascular benefit be prioritized in patients with type 2 diabetes mellitus who have not achieved glycemic targets and who have prevalent atherosclerotic cardiovascular disease. With additional cardiorenal protection trials underway, sodium-related physiological effects of SGLT2 inhibitors and clinical correlates of natriuresis, such as the impact on blood pressure, heart failure, kidney protection, and mortality, will be a major management focus.
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Affiliation(s)
- Hiddo J L Heerspink
- From Department of Clinical Pharmacy & Pharmacology, University of Groningen, University Medical Center Groningen, Netherlands (H.J.L.H.); Department of Medicine, Division of Endocrinology, Mount Sinai Hospital, University of Toronto, ON, Canada (B.A.P.); Department of Medicine, Division of Cardiology, St. Michael's Hospital, University of Toronto, ON, Canada (D.H.F.); Ted Rogers Centre for Heart Research and Department of Medicine, Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University of Toronto, ON, Canada (M.H.); Department of Medicine, Division of Nephrology, Toronto General Hospital, Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, ON, Canada (D.Z.I.C.); Department of Physiology, University of Toronto, ON, Canada (D.Z.I.C.); and Banting and Best Diabetes Centre, University of Toronto, ON, Canada (D.Z.I.C.)
| | - Bruce A Perkins
- From Department of Clinical Pharmacy & Pharmacology, University of Groningen, University Medical Center Groningen, Netherlands (H.J.L.H.); Department of Medicine, Division of Endocrinology, Mount Sinai Hospital, University of Toronto, ON, Canada (B.A.P.); Department of Medicine, Division of Cardiology, St. Michael's Hospital, University of Toronto, ON, Canada (D.H.F.); Ted Rogers Centre for Heart Research and Department of Medicine, Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University of Toronto, ON, Canada (M.H.); Department of Medicine, Division of Nephrology, Toronto General Hospital, Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, ON, Canada (D.Z.I.C.); Department of Physiology, University of Toronto, ON, Canada (D.Z.I.C.); and Banting and Best Diabetes Centre, University of Toronto, ON, Canada (D.Z.I.C.)
| | - David H Fitchett
- From Department of Clinical Pharmacy & Pharmacology, University of Groningen, University Medical Center Groningen, Netherlands (H.J.L.H.); Department of Medicine, Division of Endocrinology, Mount Sinai Hospital, University of Toronto, ON, Canada (B.A.P.); Department of Medicine, Division of Cardiology, St. Michael's Hospital, University of Toronto, ON, Canada (D.H.F.); Ted Rogers Centre for Heart Research and Department of Medicine, Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University of Toronto, ON, Canada (M.H.); Department of Medicine, Division of Nephrology, Toronto General Hospital, Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, ON, Canada (D.Z.I.C.); Department of Physiology, University of Toronto, ON, Canada (D.Z.I.C.); and Banting and Best Diabetes Centre, University of Toronto, ON, Canada (D.Z.I.C.)
| | - Mansoor Husain
- From Department of Clinical Pharmacy & Pharmacology, University of Groningen, University Medical Center Groningen, Netherlands (H.J.L.H.); Department of Medicine, Division of Endocrinology, Mount Sinai Hospital, University of Toronto, ON, Canada (B.A.P.); Department of Medicine, Division of Cardiology, St. Michael's Hospital, University of Toronto, ON, Canada (D.H.F.); Ted Rogers Centre for Heart Research and Department of Medicine, Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University of Toronto, ON, Canada (M.H.); Department of Medicine, Division of Nephrology, Toronto General Hospital, Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, ON, Canada (D.Z.I.C.); Department of Physiology, University of Toronto, ON, Canada (D.Z.I.C.); and Banting and Best Diabetes Centre, University of Toronto, ON, Canada (D.Z.I.C.)
| | - David Z I Cherney
- From Department of Clinical Pharmacy & Pharmacology, University of Groningen, University Medical Center Groningen, Netherlands (H.J.L.H.); Department of Medicine, Division of Endocrinology, Mount Sinai Hospital, University of Toronto, ON, Canada (B.A.P.); Department of Medicine, Division of Cardiology, St. Michael's Hospital, University of Toronto, ON, Canada (D.H.F.); Ted Rogers Centre for Heart Research and Department of Medicine, Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University of Toronto, ON, Canada (M.H.); Department of Medicine, Division of Nephrology, Toronto General Hospital, Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, ON, Canada (D.Z.I.C.); Department of Physiology, University of Toronto, ON, Canada (D.Z.I.C.); and Banting and Best Diabetes Centre, University of Toronto, ON, Canada (D.Z.I.C.).
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25
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Lytvyn Y, Bjornstad P, Pun N, Cherney DZI. New and old agents in the management of diabetic nephropathy. Curr Opin Nephrol Hypertens 2016; 25:232-9. [PMID: 26890303 PMCID: PMC5841607 DOI: 10.1097/mnh.0000000000000214] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW Diabetic nephropathy is a long-standing complication of diabetes mellitus and is responsible for more than 40% of end-stage renal disease cases in developed countries. Unfortunately, conventional renin-angiotensin-aldosterone system (RAAS) inhibitor medications only partially protect against the development and progression of diabetic nephropathy. Moreover, RAAS inhibitors have failed as primary prevention therapy in type 1 diabetes. Thus, agents targeting alternative pathogenic mechanisms leading to diabetic nephropathy have been intensively investigated, which is the topic of this review. RECENT FINDINGS Promising emerging agents have targeted neurohormonal activation (alternative components of the RAAS and neprilysin inhibition), tubuloglomerular feedback mechanisms (sodium glucose cotransporter 2 inhibition and incretin-based therapy) and renal inflammation/fibrosis. SUMMARY Evidence demonstrating the potential of these agents to protect and prevent progression of diabetic nephropathy is summarized in this review. There are dedicated clinical trials ongoing with these therapies, which have the potential to change the clinical practice.
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Affiliation(s)
- Yuliya Lytvyn
- aDivision of Nephrology, Department of Medicine, University Health Network bDepartment of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada cDepartment of Pediatric Endocrinology, University of Colorado School of Medicine dBarbara Davis Center for Diabetes, University of Colorado School of Medicine, Aurora, Colorado, USA *Drs Lytvyn, Bjornstad and Pun are the co-first authors of the article
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Wang X, Chandrashekar K, Wang L, Lai EY, Wei J, Zhang G, Wang S, Zhang J, Juncos LA, Liu R. Inhibition of Nitric Oxide Synthase 1 Induces Salt-Sensitive Hypertension in Nitric Oxide Synthase 1α Knockout and Wild-Type Mice. Hypertension 2016; 67:792-9. [PMID: 26883268 DOI: 10.1161/hypertensionaha.115.07032] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 01/18/2016] [Indexed: 01/10/2023]
Abstract
We recently showed that α, β, and γ splice variants of neuronal nitric oxide synthase (NOS1) expressed in the macula densa and NOS1β accounts for most of the NO generation. We have also demonstrated that the mice with deletion of NOS1 specifically from the macula densa developed salt-sensitive hypertension. However, the global NOS1 knockout (NOS1KO) strain is neither hypertensive nor salt sensitive. This global NOS1KO strain is actually an NOS1αKO model. Consequently, we hypothesized that inhibition of NOS1β in NOS1αKO mice induces salt-sensitive hypertension. NOS1αKO and C57BL/6 wild-type (WT) mice were implanted with telemetry transmitters and divided into 7-nitroindazole (10 mg/kg/d)-treated and nontreated groups. All of the mice were fed a normal salt (0.4% NaCl) diet for 5 days, followed by a high-salt diet (4% NaCl). NO generation by the macula densa was inhibited by >90% in WT and NOS1αKO mice treated with 7-nitroindazole. Glomerular filtration rate in conscious mice was increased by ≈ 40% after a high-salt diet in both NOS1αKO and WT mice. In response to acute volume expansion, glomerular filtration rate, diuretic and natriuretic response were significantly blunted in the WT and knockout mice treated with 7-nitroindazole. Mean arterial pressure had no significant changes in mice fed a high-salt diet, but increased ≈ 15 mm Hg similarly in NOS1αKO and WT mice treated with 7-nitroindazole. We conclude that NOS1β, but not NOS1α, plays an important role in control of sodium excretion and hemodynamics in response to either an acute or a chronic salt loading.
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Affiliation(s)
- Ximing Wang
- From the Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (X.W., L.W., J.W., G.Z., S.W., J.Z., R.L.); Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong, China (X.W.); Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (K.C., L.A.J.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L., G.Z.)
| | - Kiran Chandrashekar
- From the Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (X.W., L.W., J.W., G.Z., S.W., J.Z., R.L.); Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong, China (X.W.); Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (K.C., L.A.J.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L., G.Z.)
| | - Lei Wang
- From the Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (X.W., L.W., J.W., G.Z., S.W., J.Z., R.L.); Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong, China (X.W.); Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (K.C., L.A.J.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L., G.Z.)
| | - En Yin Lai
- From the Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (X.W., L.W., J.W., G.Z., S.W., J.Z., R.L.); Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong, China (X.W.); Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (K.C., L.A.J.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L., G.Z.)
| | - Jin Wei
- From the Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (X.W., L.W., J.W., G.Z., S.W., J.Z., R.L.); Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong, China (X.W.); Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (K.C., L.A.J.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L., G.Z.)
| | - Gensheng Zhang
- From the Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (X.W., L.W., J.W., G.Z., S.W., J.Z., R.L.); Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong, China (X.W.); Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (K.C., L.A.J.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L., G.Z.)
| | - Shaohui Wang
- From the Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (X.W., L.W., J.W., G.Z., S.W., J.Z., R.L.); Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong, China (X.W.); Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (K.C., L.A.J.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L., G.Z.)
| | - Jie Zhang
- From the Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (X.W., L.W., J.W., G.Z., S.W., J.Z., R.L.); Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong, China (X.W.); Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (K.C., L.A.J.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L., G.Z.)
| | - Luis A Juncos
- From the Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (X.W., L.W., J.W., G.Z., S.W., J.Z., R.L.); Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong, China (X.W.); Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (K.C., L.A.J.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L., G.Z.)
| | - Ruisheng Liu
- From the Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa (X.W., L.W., J.W., G.Z., S.W., J.Z., R.L.); Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong, China (X.W.); Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (K.C., L.A.J.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L., G.Z.).
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Kretschmar C, Oyarzún C, Villablanca C, Jaramillo C, Alarcón S, Perez G, Díaz-Encarnación MM, Pastor-Anglada M, Garrido W, Quezada C, San Martín R. Reduced Adenosine Uptake and Its Contribution to Signaling that Mediates Profibrotic Activation in Renal Tubular Epithelial Cells: Implication in Diabetic Nephropathy. PLoS One 2016; 11:e0147430. [PMID: 26808537 PMCID: PMC4726618 DOI: 10.1371/journal.pone.0147430] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 01/03/2016] [Indexed: 11/18/2022] Open
Abstract
Altered nucleoside levels may be linked to pathogenic signaling through adenosine receptors. We hypothesized that adenosine dysregulation contributes to fibrosis in diabetic kidney disease. Our findings indicate that high glucose levels and experimental diabetes decreased uptake activity through the equilibrative nucleoside transporter 1 (ENT1) in proximal tubule cells. In addition, a correlation between increased plasma content of adenosine and a marker of renal fibrosis in diabetic rats was evidenced. At the cellular level, exposure of HK2 cells to high glucose, TGF-β and the general adenosine receptor agonist NECA, induced the expression of profibrotic cell activation markers α-SMA and fibronectin. These effects can be avoided by using a selective antagonist of the adenosine A3 receptor subtype in vitro. Furthermore, induction of fibrosis marker α-SMA was prevented by the A3 receptor antagonist in diabetic rat kidneys. In conclusion, we evidenced the contribution of purinergic signaling to renal fibrosis in experimental diabetic nephropathy.
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Affiliation(s)
- Catalina Kretschmar
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Carlos Oyarzún
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Cristopher Villablanca
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Catherinne Jaramillo
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Sebastián Alarcón
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Gustavo Perez
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | | | - Marçal Pastor-Anglada
- Institute of Biomedicine and Oncology Programme, National Biomedical Research Institute of Liver and Gastrointestinal Diseases (CIBER EHD), Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona, Spain
| | - Wallys Garrido
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Claudia Quezada
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Rody San Martín
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
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Ding HH, Ni WJ, Tang LQ, Wei W. G protein-coupled receptors: potential therapeutic targets for diabetic nephropathy. J Recept Signal Transduct Res 2015; 36:411-421. [PMID: 26675443 DOI: 10.3109/10799893.2015.1122039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Diabetic nephropathy, a lethal microvascular complication of diabetes mellitus, is characterized by progressive albuminuria, excessive deposition of extracellular matrix, thickened glomerular basement membrane, podocyte abnormalities, and podocyte loss. The G protein-coupled receptors (GPCRs) have attracted considerable attention in diabetic nephropathy, but the specific effects have not been elucidated yet. Likewise, abnormal signaling pathways are closely interrelated to the pathologic process of diabetic nephropathy, despite the fact that the mechanisms have not been explored clearly. Therefore, GPCRs and its mediated signaling pathways are essential for priority research, so that preventative strategies and potential targets might be developed for diabetic nephropathy. This article will give us comprehensive overview of predominant GPCR types, roles, and correlative signaling pathways in diabetic nephropathy.
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Affiliation(s)
- Hai-Hua Ding
- a Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-Inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University , Hefei, Anhui Province , People's Republic of China.,b Affiliated Anhui Provincial Hospital, Anhui Medical University , Hefei, Anhui Province , People's Republic of China
| | - Wei-Jian Ni
- b Affiliated Anhui Provincial Hospital, Anhui Medical University , Hefei, Anhui Province , People's Republic of China
| | - Li-Qin Tang
- b Affiliated Anhui Provincial Hospital, Anhui Medical University , Hefei, Anhui Province , People's Republic of China
| | - Wei Wei
- a Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-Inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University , Hefei, Anhui Province , People's Republic of China
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Sodium-glucose cotransporter-2 inhibition and the potential for renal protection in diabetic nephropathy. Curr Opin Nephrol Hypertens 2015; 24:96-103. [PMID: 25470017 DOI: 10.1097/mnh.0000000000000084] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
PURPOSE OF REVIEW Renal hyperfiltration has been used as a surrogate marker for increased intraglomerular pressure in patients with diabetes mellitus. Previous human investigation examining the pathogenesis of hyperfiltration has focused on the role of neurohormones such as the renin-angiotensin-aldosterone system (RAAS). Unfortunately, RAAS blockade does not completely attenuate hyperfiltration or diabetic kidney injury. More recent work has therefore investigated the contribution of renal tubular factors, including the sodium-glucose cotransporter, to the hyperfiltration state, which is the topic of this review. RECENT FINDINGS Novel sodium-glucose cotransporter-2 (SGLT2) inhibitors reduce proximal tubular sodium reabsorption, thereby increasing distal sodium delivery to the macula densa, causing tubuloglomerular feedback, afferent vasoconstriction and decreased hyperfiltration in animals. In humans, SGLT2 inhibition was recently shown to reduce hyperfiltration in normotensive, normoalbuminuric patients with type 1 diabetes. In clinical trials of type 2 diabetes, SGLT2 is associated with significant renal effects, including modest, acute declines in estimated glomerular filtration rate followed by the maintenance of stable renal function, and reduced albuminuria. SUMMARY Existing data are supportive of a potential renal-protective role for SGLT2 inhibition in patients with diabetes. Dedicated renal outcome trials are ongoing and have the potential to change the clinical practice.
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O'Neill J, Fasching A, Pihl L, Patinha D, Franzén S, Palm F. Acute SGLT inhibition normalizes O2 tension in the renal cortex but causes hypoxia in the renal medulla in anaesthetized control and diabetic rats. Am J Physiol Renal Physiol 2015; 309:F227-34. [PMID: 26041448 DOI: 10.1152/ajprenal.00689.2014] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 05/31/2015] [Indexed: 12/25/2022] Open
Abstract
Early stage diabetic nephropathy is characterized by glomerular hyperfiltration and reduced renal tissue Po2. Recent observations have indicated that increased tubular Na(+)-glucose linked transport (SGLT) plays a role in the development of diabetes-induced hyperfiltration. The aim of the present study was to determine how inhibition of SLGT impacts upon Po2 in the diabetic rat kidney. Diabetes was induced by streptozotocin in Sprague-Dawley rats 2 wk before experimentation. Renal hemodynamics, excretory function, and renal O2 homeostasis were measured in anesthetized control and diabetic rats during baseline and after acute SGLT inhibition using phlorizin (200 mg/kg ip). Baseline arterial pressure was similar in both groups and unaffected by SGLT inhibition. Diabetic animals displayed reduced baseline Po2 in both the cortex and medulla. SGLT inhibition improved cortical Po2 in the diabetic kidney, whereas it reduced medullary Po2 in both groups. SGLT inhibition reduced Na(+) transport efficiency [tubular Na(+) transport (TNa)/renal O2 consumption (Qo2)] in the control kidney, whereas the already reduced TNa/Qo2 in the diabetic kidney was unaffected by SGLT inhibition. In conclusion, these data demonstrate that when SGLT is inhibited, renal cortex Po2 in the diabetic rat kidney is normalized, which implies that increased proximal tubule transport contributes to the development of hypoxia in the diabetic kidney. The reduction in medullary Po2 in both control and diabetic kidneys during the inhibition of proximal Na(+) reabsorption suggests the redistribution of active Na(+) transport to less efficient nephron segments, such as the medullary thick ascending limb, which results in medullary hypoxia.
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Affiliation(s)
- Julie O'Neill
- Division of Drug Research, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden; and
| | - Angelica Fasching
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Liselotte Pihl
- Division of Drug Research, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden; and
| | - Daniela Patinha
- Division of Drug Research, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden; and
| | - Stephanie Franzén
- Division of Drug Research, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden; and
| | - Fredrik Palm
- Division of Drug Research, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden; and Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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Abstract
Intrarenal autoregulatory mechanisms maintain renal blood flow (RBF) and glomerular filtration rate (GFR) independent of renal perfusion pressure (RPP) over a defined range (80-180 mmHg). Such autoregulation is mediated largely by the myogenic and the macula densa-tubuloglomerular feedback (MD-TGF) responses that regulate preglomerular vasomotor tone primarily of the afferent arteriole. Differences in response times allow separation of these mechanisms in the time and frequency domains. Mechanotransduction initiating the myogenic response requires a sensing mechanism activated by stretch of vascular smooth muscle cells (VSMCs) and coupled to intracellular signaling pathways eliciting plasma membrane depolarization and a rise in cytosolic free calcium concentration ([Ca(2+)]i). Proposed mechanosensors include epithelial sodium channels (ENaC), integrins, and/or transient receptor potential (TRP) channels. Increased [Ca(2+)]i occurs predominantly by Ca(2+) influx through L-type voltage-operated Ca(2+) channels (VOCC). Increased [Ca(2+)]i activates inositol trisphosphate receptors (IP3R) and ryanodine receptors (RyR) to mobilize Ca(2+) from sarcoplasmic reticular stores. Myogenic vasoconstriction is sustained by increased Ca(2+) sensitivity, mediated by protein kinase C and Rho/Rho-kinase that favors a positive balance between myosin light-chain kinase and phosphatase. Increased RPP activates MD-TGF by transducing a signal of epithelial MD salt reabsorption to adjust afferent arteriolar vasoconstriction. A combination of vascular and tubular mechanisms, novel to the kidney, provides for high autoregulatory efficiency that maintains RBF and GFR, stabilizes sodium excretion, and buffers transmission of RPP to sensitive glomerular capillaries, thereby protecting against hypertensive barotrauma. A unique aspect of the myogenic response in the renal vasculature is modulation of its strength and speed by the MD-TGF and by a connecting tubule glomerular feedback (CT-GF) mechanism. Reactive oxygen species and nitric oxide are modulators of myogenic and MD-TGF mechanisms. Attenuated renal autoregulation contributes to renal damage in many, but not all, models of renal, diabetic, and hypertensive diseases. This review provides a summary of our current knowledge regarding underlying mechanisms enabling renal autoregulation in health and disease and methods used for its study.
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Affiliation(s)
- Mattias Carlström
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Christopher S Wilcox
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - William J Arendshorst
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Persson P, Hansell P, Palm F. Reduced adenosine A2a receptor–mediated efferent arteriolar vasodilation contributes to diabetes-induced glomerular hyperfiltration. Kidney Int 2015; 87:109-15. [DOI: 10.1038/ki.2014.219] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 04/17/2014] [Accepted: 05/01/2014] [Indexed: 11/09/2022]
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Cherney DZ, Perkins BA. Sodium-Glucose Cotransporter 2 Inhibition in Type 1 Diabetes: Simultaneous Glucose Lowering and Renal Protection? Can J Diabetes 2014; 38:356-63. [DOI: 10.1016/j.jcjd.2014.05.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 04/30/2014] [Accepted: 05/09/2014] [Indexed: 01/10/2023]
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Blantz RC, Singh P. Glomerular and tubular function in the diabetic kidney. Adv Chronic Kidney Dis 2014; 21:297-303. [PMID: 24780458 DOI: 10.1053/j.ackd.2014.03.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 03/09/2014] [Accepted: 03/10/2014] [Indexed: 01/11/2023]
Abstract
Diabetes mellitus with its attendant complications is a significant cause of morbidity and mortality with diabetic nephropathy being the leading cause of end stage renal disease in the Western world. Characteristic structural and functional changes in the kidney early in the course of diabetes have been shown to have enduring effects on the progression of disease. A better understanding of the mechanisms underlying these changes is imperative to the development of new therapeutic strategies. Renal hypertrophy and hyperfiltration along with proximal tubular hyperreabsorption are among the distinctive features of early diabetic nephropathy. Additionally, there are particular alterations in the sensitivity of the glomerular and tubular function to dietary salt intake in early diabetes. Herein, we focus on these early physiologic changes and discuss some of the primary and secondary mechanisms discovered in recent years which lead to these alterations in kidney function.
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Pruijm M, Hofmann L, Piskunowicz M, Muller ME, Zweiacker C, Bassi I, Vogt B, Stuber M, Burnier M. Determinants of renal tissue oxygenation as measured with BOLD-MRI in chronic kidney disease and hypertension in humans. PLoS One 2014; 9:e95895. [PMID: 24760031 PMCID: PMC3997480 DOI: 10.1371/journal.pone.0095895] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 04/01/2014] [Indexed: 11/19/2022] Open
Abstract
Experimentally renal tissue hypoxia appears to play an important role in the pathogenesis of chronic kidney disease (CKD) and arterial hypertension (AHT). In this study we measured renal tissue oxygenation and its determinants in humans using blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) under standardized hydration conditions. Four coronal slices were selected, and a multi gradient echo sequence was used to acquire T2* weighted images. The mean cortical and medullary R2* values ( = 1/T2*) were calculated before and after administration of IV furosemide, a low R2* indicating a high tissue oxygenation. We studied 195 subjects (95 CKD, 58 treated AHT, and 42 healthy controls). Mean cortical R2 and medullary R2* were not significantly different between the groups at baseline. In stimulated conditions (furosemide injection), the decrease in R2* was significantly blunted in patients with CKD and AHT. In multivariate linear regression analyses, neither cortical nor medullary R2* were associated with eGFR or blood pressure, but cortical R2* correlated positively with male gender, blood glucose and uric acid levels. In conclusion, our data show that kidney oxygenation is tightly regulated in CKD and hypertensive patients at rest. However, the metabolic response to acute changes in sodium transport is altered in CKD and in AHT, despite preserved renal function in the latter group. This suggests the presence of early renal metabolic alterations in hypertension. The correlations between cortical R2* values, male gender, glycemia and uric acid levels suggest that these factors interfere with the regulation of renal tissue oxygenation.
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Affiliation(s)
- Menno Pruijm
- Department of Nephrology, University Hospital, Lausanne, Switzerland
| | - Lucie Hofmann
- Department of Nephrology and Hypertension, Bern University Hospital, Bern, Switzerland
| | | | - Marie-Eve Muller
- Department of Nephrology, University Hospital, Lausanne, Switzerland
| | - Carole Zweiacker
- Department of Nephrology, University Hospital, Lausanne, Switzerland
| | - Isabelle Bassi
- Department of Nephrology, University Hospital, Lausanne, Switzerland
| | - Bruno Vogt
- Department of Nephrology and Hypertension, Bern University Hospital, Bern, Switzerland
| | - Matthias Stuber
- Department of Radiology, University Hospital, Lausanne, Switzerland
| | - Michel Burnier
- Department of Nephrology, University Hospital, Lausanne, Switzerland
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Patinha D, Afonso J, Sousa T, Morato M, Albino-Teixeira A. Activation of adenosine receptors improves renal antioxidant status in diabetic Wistar but not SHR rats. Ups J Med Sci 2014; 119:10-8. [PMID: 24195577 PMCID: PMC3916712 DOI: 10.3109/03009734.2013.851748] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Diabetes and hypertension independently contribute to renal injury, and the major mechanisms involved are increased reactive oxygen species (ROS) bioavailability and renin-angiotensin system (RAS) activation. We investigated the role of adenosine in controlling ROS production and RAS activation associated with renal dysfunction in hypertension and diabetes. METHODS Fourteen days after induction of diabetes with streptozotocin in 12-week-old male Wistar and spontaneously hypertensive (SHR) rats, animals were treated during 7 days with 2-chloroadenosine (CADO group, 5 mg/kg/d), a stable analogue of adenosine, or underwent a sham operation procedure. At the end of the study (day 21), intra-arterial systolic blood pressure (SBP) was measured, and 24-h urine and plasma samples and renal tissue were collected. RESULTS CADO treatment decreased the plasma glucose concentration and glucose and protein excretion by more than 30% in both strains. CADO treatment decreased SBP in diabetic SHR rats (143 ± 8 versus 114 ± 4 mmHg, p < 0.05), but not in diabetic Wistar rats. The hypotensive effect of CADO was associated to a ∼70% increase in plasma angiotensinogen (AGT) concentration and a ∼50% decrease in urinary AGT excretion. CADO also caused a decrease in medullary and cortical hydrogen peroxide production of about 40%, which was associated with a proportional increase in glutathione peroxidase (GPx) activity in diabetic Wistar but not in diabetic SHR animals. CONCLUSIONS These results suggest that activation of adenosine receptors improves renal antioxidant capacity in diabetic Wistar but not SHR rats, although it improves glucose metabolism in both strains. Furthermore, activation of adenosine receptors does not seem to be directly influencing AGT production.
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Affiliation(s)
- Daniela Patinha
- Departamento de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
- Neurofarmacologia, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Joana Afonso
- Departamento de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Teresa Sousa
- Departamento de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Manuela Morato
- Departamento de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
- Neurofarmacologia, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Laboratório de Farmacologia, Departamento de Ciências do Medicamento, Faculdade de Farmácia, REQUIMTE, Universidade do Porto, Porto, Portugal
| | - António Albino-Teixeira
- Departamento de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
- Neurofarmacologia, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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Sällström J, Eriksson T, Fredholm BB, Persson AEG, Palm F. Inhibition of sodium-linked glucose reabsorption normalizes diabetes-induced glomerular hyperfiltration in conscious adenosine A₁-receptor deficient mice. Acta Physiol (Oxf) 2014; 210:440-5. [PMID: 23901799 DOI: 10.1111/apha.12152] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 05/07/2013] [Accepted: 07/28/2013] [Indexed: 02/05/2023]
Abstract
AIM Glomerular hyperfiltration is commonly observed in diabetics early after the onset of the disease and predicts the progression of nephropathy. Sustained hyperglycaemia is also closely associated with kidney hypertrophy and increased electrolyte and glucose reabsorption in the proximal tubule. In this study, we investigated the role of the increased tubular sodium/glucose cotransport for diabetes-induced glomerular hyperfiltration. To eliminate any potential confounding effect of the tubuloglomerular feedback (TGF) mechanism, we used adenosine A₁-receptor deficient (A1AR(-/-)) mice known to lack a functional TGF mechanism and compared the results to corresponding wild-type animals (A1AR(+/+)). METHODS Diabetes was induced by an intravenous bolus injection of alloxan. Glomerular filtration rate (GFR) was determined in conscious mice by a single bolus injection of inulin. The sodium/glucose cotransporters were inhibited by phlorizin 30 min prior to GFR measurements. RESULTS Normoglycaemic animals had a similar GFR independent of genotype (A₁AR(+/+) 233 ± 11 vs. A₁AR(-/-) 241 ± 25 μL min(-1)), and induction of diabetes resulted in glomerular hyperfiltration in both groups (A₁AR(+/+) 380 ± 25 vs. A₁AR(-/-) 336 ± 35 μL min(-1); both P < 0.05). Phlorizin had no effect on GFR in normoglycaemic mice, whereas it reduced GFR in both genotypes during diabetes (A₁AR(+/+) 365 ± 18 to 295 ± 19, A₁AR(-/-) 354 ± 38 to 199 ± 15 μL min(-1); both P < 0.05). Notably, the reduction was more pronounced in the A₁AR(-/-) (P < 0.05). CONCLUSION This study demonstrates that increased tubular sodium/glucose reabsorption is important for diabetes-induced hyperfiltration, and that the TGF mechanism is not involved in these alterations, but rather functions to reduce any deviations from a new set-point.
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Affiliation(s)
- J. Sällström
- Department of Medical Cell Biology; Uppsala University; Uppsala Sweden
| | - T. Eriksson
- Department of Medical Cell Biology; Uppsala University; Uppsala Sweden
| | - B. B. Fredholm
- Department of Physiology and Pharmacology; Karolinska Institute; Stockholm Sweden
| | - A. E. G. Persson
- Department of Medical Cell Biology; Uppsala University; Uppsala Sweden
| | - F. Palm
- Department of Medical Cell Biology; Uppsala University; Uppsala Sweden
- Division of Drug Research; Department of Medical and Health Sciences; Center for Medical Image Science and Visualization; Linköping University; Linköping Sweden
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Tikellis C, Brown R, Head GA, Cooper ME, Thomas MC. Angiotensin-converting enzyme 2 mediates hyperfiltration associated with diabetes. Am J Physiol Renal Physiol 2014; 306:F773-80. [PMID: 24477684 DOI: 10.1152/ajprenal.00264.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The degradation of ANG II by angiotensin-converting enzyme 2 (ACE2), leading to the formation of ANG(1-7), is an important step in the regulation of the renin-angiotensin-aldosterone system (RAAS), and one that is significantly altered in the diabetic kidney. This study examined the role of ACE2 in the hyperfiltration associated with diabetes. Streptozotocin diabetes was induced in male C57BL6 mice and ACE2 knockout (KO) mice. C57BL6 mice were further randomized to receive the selective ACE2 inhibitor MLN-4760. After 2 wk of study, animals were subjected to micropuncture experiments. The renal reserve was further assessed in C57BL6 mice and ACE2 KO mice after exposure to a high-protein diet. The induction of diabetes in wild-type mice was associated with increased renal ACE2 activity, hyperfiltration, and renal hypertrophy. On micropuncture, diabetes was associated with increased tubular free flow and stop-flow pressure, enhanced tubuloglomerular feedback reactivity, and an increased maximal response indicative of increased glomerular hydrostatic capillary pressure. Each of these increases were prevented in diabetic ACE2 KO mice and diabetic mice treated with a selective ACE2 inhibitor for 2 wk. However, unlike chronically treated animals, ACE2 inhibition with MLN-4760 had no acute effect on stop-flow pressure or tubuloglomerular feedback reactivity. ACE2 KO mice also failed to increase their creatinine clearance in response to a high-protein diet. The results of our study suggest that ACE2 plays a key role in the recruitment of the renal reserve and hyperfiltration associated with diabetes.
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Affiliation(s)
- Chris Tikellis
- Baker IDI Heart and Diabetes Institute, PO Box 6492, St Kilda Central, Melbourne 8008, Victoria, Australia.
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39
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Abstract
Diabetes mellitus contributes greatly to morbidity, mortality, and overall health care costs. In major part, these outcomes derive from the high incidence of progressive kidney dysfunction in patients with diabetes making diabetic nephropathy a leading cause of end-stage renal disease. A better understanding of the molecular mechanism involved and of the early dysfunctions observed in the diabetic kidney may permit the development of new strategies to prevent diabetic nephropathy. Here we review the pathophysiological changes that occur in the kidney in response to hyperglycemia, including the cellular responses to high glucose and the responses in vascular, glomerular, podocyte, and tubular function. The molecular basis, characteristics, and consequences of the unique growth phenotypes observed in the diabetic kidney, including glomerular structures and tubular segments, are outlined. We delineate mechanisms of early diabetic glomerular hyperfiltration including primary vascular events as well as the primary role of tubular growth, hyperreabsorption, and tubuloglomerular communication as part of a "tubulocentric" concept of early diabetic kidney function. The latter also explains the "salt paradox" of the early diabetic kidney, that is, a unique and inverse relationship between glomerular filtration rate and dietary salt intake. The mechanisms and consequences of the intrarenal activation of the renin-angiotensin system and of diabetes-induced tubular glycogen accumulation are discussed. Moreover, we aim to link the changes that occur early in the diabetic kidney including the growth phenotype, oxidative stress, hypoxia, and formation of advanced glycation end products to mechanisms involved in progressive kidney disease.
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Affiliation(s)
- Volker Vallon
- Department of Medicine, University of California San Diego & VA San Diego Healthcare System, San Diego, California, USA.
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Vallon V, Gerasimova M, Rose MA, Masuda T, Satriano J, Mayoux E, Koepsell H, Thomson SC, Rieg T. SGLT2 inhibitor empagliflozin reduces renal growth and albuminuria in proportion to hyperglycemia and prevents glomerular hyperfiltration in diabetic Akita mice. Am J Physiol Renal Physiol 2013; 306:F194-204. [PMID: 24226524 DOI: 10.1152/ajprenal.00520.2013] [Citation(s) in RCA: 348] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Our previous work has shown that gene knockout of the sodium-glucose cotransporter SGLT2 modestly lowered blood glucose in streptozotocin-diabetic mice (BG; from 470 to 300 mg/dl) and prevented glomerular hyperfiltration but did not attenuate albuminuria or renal growth and inflammation. Here we determined effects of the SGLT2 inhibitor empagliflozin (300 mg/kg of diet for 15 wk; corresponding to 60-80 mg·kg(-1)·day(-1)) in type 1 diabetic Akita mice that, opposite to streptozotocin-diabetes, upregulate renal SGLT2 expression. Akita diabetes, empagliflozin, and Akita + empagliflozin similarly increased renal membrane SGLT2 expression (by 38-56%) and reduced the expression of SGLT1 (by 33-37%) vs. vehicle-treated wild-type controls (WT). The diabetes-induced changes in SGLT2/SGLT1 protein expression are expected to enhance the BG-lowering potential of SGLT2 inhibition, and empagliflozin strongly lowered BG in Akita (means of 187-237 vs. 517-535 mg/dl in vehicle group; 100-140 mg/dl in WT). Empagliflozin modestly reduced GFR in WT (250 vs. 306 μl/min) and completely prevented the diabetes-induced increase in glomerular filtration rate (GFR) (255 vs. 397 μl/min). Empagliflozin attenuated increases in kidney weight and urinary albumin/creatinine ratio in Akita in proportion to hyperglycemia. Empagliflozin did not increase urinary glucose/creatinine ratios in Akita, indicating the reduction in filtered glucose balanced the inhibition of glucose reabsorption. Empagliflozin attenuated/prevented the increase in systolic blood pressure, glomerular size, and molecular markers of kidney growth, inflammation, and gluconeogenesis in Akita. We propose that SGLT2 inhibition can lower GFR independent of reducing BG (consistent with the tubular hypothesis of diabetic glomerular hyperfiltration), while attenuation of albuminuria, kidney growth, and inflammation in the early diabetic kidney may mostly be secondary to lower BG.
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Affiliation(s)
- Volker Vallon
- Div. of Nephrology and Hypertension, Depts. of Medicine and Pharmacology, Univ. of California San Diego and Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Dr. (9151 San Diego, CA 92161.
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41
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Declèves AE, Rychak JJ, Smith DJ, Sharma K. Effects of high-fat diet and losartan on renal cortical blood flow using contrast ultrasound imaging. Am J Physiol Renal Physiol 2013; 305:F1343-51. [PMID: 24049144 DOI: 10.1152/ajprenal.00326.2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Obesity-related kidney disease occurs as a result of complex interactions between metabolic and hemodynamic effects. Changes in microvascular perfusion may play a major role in kidney disease; however, these changes are difficult to assess in vivo. Here, we used perfusion ultrasound imaging to evaluate cortical blood flow in a mouse model of high-fat diet-induced kidney disease. C57BL/6J mice were randomized to a standard diet (STD) or a high-fat diet (HFD) for 30 wk and then treated either with losartan or a placebo for an additional 6 wk. Noninvasive ultrasound perfusion imaging of the kidney was performed during infusion of a microbubble contrast agent. Blood flow within the microvasculature of the renal cortex and medulla was derived from imaging data. An increase in the time required to achieve full cortical perfusion was observed for HFD mice relative to STD. This was reversed following treatment with losartan. These data were concurrent with an increased glomerular filtration rate in HFD mice compared with STD- or HFD-losartan-treated mice. Losartan treatment also abrogated fibro-inflammatory disease, assessed by markers at the protein and messenger level. Finally, a reduction in capillary density was found in HFD mice, and this was reversed upon losartan treatment. This suggests that alterations in vascular density may be responsible for the elevated perfusion time observed by imaging. These data demonstrate that ultrasound contrast imaging is a robust and sensitive method for evaluating changes in renal microvascular perfusion and that cortical perfusion time may be a useful parameter for evaluating obesity-related renal disease.
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Affiliation(s)
- Anne-Emilie Declèves
- Center for Renal Translational Medicine, Division of Nephrology-Hypertension, 405 Stein Clinical Research Bldg., MC 0711, Univ. of California San Diego, La Jolla, CA, 92093.
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Abstract
The pancreas is an organ with a central role in nutrient breakdown, nutrient sensing and release of hormones regulating whole body nutrient homeostasis. In diabetes mellitus, the balance is broken-cells can be starving in the midst of plenty. There are indications that the incidence of diabetes type 1 and 2, and possibly pancreatogenic diabetes, is rising globally. Events leading to insulin secretion and action are complex, but there is emerging evidence that intracellular nucleotides and nucleotides are not only important as intracellular energy molecules but also as extracellular signalling molecules in purinergic signalling cascades. This signalling takes place at the level of the pancreas, where the close apposition of various cells-endocrine, exocrine, stromal and immune cells-contributes to the integrated function. Following an introduction to diabetes, the pancreas and purinergic signalling, we will focus on the role of purinergic signalling and its changes associated with diabetes in the pancreas and selected tissues/organ systems affected by hyperglycaemia and other stress molecules of diabetes. Since this is the first review of this kind, a comprehensive historical angle is taken, and common and divergent roles of receptors for nucleotides and nucleosides in different organ systems will be given. This integrated picture will aid our understanding of the challenges of the potential and currently used drugs targeted to specific organ/cells or disorders associated with diabetes.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF UK
- Department of Pharmacology, Melbourne University, Melbourne, Australia
| | - Ivana Novak
- Molecular and Integrative Physiology, Department of Biology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100 Copenhagen Ø, Denmark
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43
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Rieg T. A High-throughput method for measurement of glomerular filtration rate in conscious mice. J Vis Exp 2013:e50330. [PMID: 23712131 DOI: 10.3791/50330] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The measurement of glomerular filtration rate (GFR) is the gold standard in kidney function assessment. Currently, investigators determine GFR by measuring the level of the endogenous biomarker creatinine or exogenously applied radioactive labeled inulin ((3)H or (14)C). Creatinine has the substantial drawback that proximal tubular secretion accounts for ~50% of total renal creatinine excretion and therefore creatinine is not a reliable GFR marker. Depending on the experiment performed, inulin clearance can be determined by an intravenous single bolus injection or continuous infusion (intravenous or osmotic minipump). Both approaches require the collection of plasma or plasma and urine, respectively. Other drawbacks of radioactive labeled inulin include usage of isotopes, time consuming surgical preparation of the animals, and the requirement of a terminal experiment. Here we describe a method which uses a single bolus injection of fluorescein isothiocyanate-(FITC) labeled inulin and the measurement of its fluorescence in 1-2 μl of diluted plasma. By applying a two-compartment model, with 8 blood collections per mouse, it is possible to measure GFR in up to 24 mice per day using a special work-flow protocol. This method only requires brief isoflurane anesthesia with all the blood samples being collected in a non-restrained and awake mouse. Another advantage is that it is possible to follow mice over a period of several months and treatments (i.e. doing paired experiments with dietary changes or drug applications). We hope that this technique of measuring GFR is useful to other investigators studying mouse kidney function and will replace less accurate methods of estimating kidney function, such as plasma creatinine and blood urea nitrogen.
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Affiliation(s)
- Timo Rieg
- Division of Nephrology-Hypertension, Department of Medicine, University of California, San Diego, USA.
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44
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Abstract
Diabetic nephropathy ranks as the most devastating kidney disease worldwide. It characterizes in the early onset by glomerular hypertrophy, hyperfiltration and mesangial expansion. Experimental models show that overproduction of vascular endothelial growth factor (VEGF) is a pathogenic condition for podocytopathy; however the mechanisms that regulate this growth factor induction are not clearly identified. We determined that the adenosine A(2B) receptor (A(2B)AR) mediates VEGF overproduction in ex vivo glomeruli exposed to high glucose concentration, requiring PKCα and Erk1/2 activation. The glomerular content of A(2B)AR was concomitantly increased with VEGF at early stages of renal disease in streptozotocin-induced diabetic rats. Further, in vivo administration of an antagonist of A(2B)AR in diabetic rats blocked the glomerular overexpression of VEGF, mesangial cells activation and proteinuria. In addition, we also determined that the accumulation of extracellular adenosine occurs in glomeruli of diabetic rats. Correspondingly, raised urinary adenosine levels were found in diabetic rats. In conclusion, we evidenced that adenosine signaling at the onset of diabetic kidney disease is a pathogenic event that promotes VEGF induction.
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45
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Abstract
Obesity and diabetes are major causes of CKD and ESRD, and are thus enormous health concerns worldwide. Both obesity and diabetes, along with other elements of the metabolic syndrome including hypertension, are highly interrelated and contribute to the development and progression of renal disease. Studies show that multiple factors act in concert to initially cause renal vasodilation, glomerular hyperfiltration, and albuminuria, leading to the development of glomerulopathy. The coexistence of hypertension contributes to the disease progression, which, if not treated, may lead to ESRD. Although early intervention and management of body weight, hyperglycemia, and hypertension are imperative, novel therapeutic approaches are also necessary to reduce the high morbidity and mortality associated with both obesity-related and diabetes-related renal disease.
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Affiliation(s)
- Christine Maric-Bilkan
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216-4505, USA.
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46
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Vallon V, Rose M, Gerasimova M, Satriano J, Platt KA, Koepsell H, Cunard R, Sharma K, Thomson SC, Rieg T. Knockout of Na-glucose transporter SGLT2 attenuates hyperglycemia and glomerular hyperfiltration but not kidney growth or injury in diabetes mellitus. Am J Physiol Renal Physiol 2012; 304:F156-67. [PMID: 23152292 DOI: 10.1152/ajprenal.00409.2012] [Citation(s) in RCA: 295] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Na-glucose cotransporter SGLT2 mediates high-capacity glucose uptake in the early proximal tubule and SGLT2 inhibitors are developed as new antidiabetic drugs. We used gene-targeted Sglt2 knockout (Sglt2(-/-)) mice to elucidate the contribution of SGLT2 to blood glucose control, glomerular hyperfiltration, kidney growth, and markers of renal growth and injury at 5 wk and 4.5 mo after induction of low-dose streptozotocin (STZ) diabetes. The absence of SGLT2 did not affect renal mRNA expression of glucose transporters SGLT1, NaGLT1, GLUT1, or GLUT2 in response to STZ. Application of STZ increased blood glucose levels to a lesser extent in Sglt2(-/-) vs. wild-type (WT) mice (∼300 vs. 470 mg/dl) but increased glucosuria and food and fluid intake to similar levels in both genotypes. Lack of SGLT2 prevented STZ-induced glomerular hyperfiltration but not the increase in kidney weight. Knockout of SGLT2 attenuated the STZ-induced renal accumulation of p62/sequestosome, an indicator of impaired autophagy, but did not attenuate the rise in renal expression of markers of kidney growth (p27 and proliferating cell nuclear antigen), oxidative stress (NADPH oxidases 2 and 4 and heme oxygenase-1), inflammation (interleukin-6 and monocyte chemoattractant protein-1), fibrosis (fibronectin and Sirius red-sensitive tubulointerstitial collagen accumulation), or injury (renal/urinary neutrophil gelatinase-associated lipocalin). SGLT2 deficiency did not induce ascending urinary tract infection in nondiabetic or diabetic mice. The results indicate that SGLT2 is a determinant of hyperglycemia and glomerular hyperfiltration in STZ-induced diabetes mellitus but is not critical for the induction of renal growth and markers of renal injury, inflammation, and fibrosis.
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Affiliation(s)
- Volker Vallon
- Department of Medicine, University of California, San Diego, California 92161, USA.
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47
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Takenaka T, Inoue T, Ohno Y, Miyazaki T, Nishiyama A, Ishii N, Suzuki H. Elucidating mechanisms underlying altered renal autoregulation in diabetes. Am J Physiol Regul Integr Comp Physiol 2012; 303:R495-504. [PMID: 22739351 DOI: 10.1152/ajpregu.00217.2012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Previous studies have reported that high-salt intake paradoxically activates tubuloglomerular feedback (TGF) in type 1 diabetes. Using Zucker lean (ZL) and diabetic fatty (ZDF) rats on normal and high-salt diets, renal hemodynamics and the renin-angiotensin system (RAS) were characterized. On normal salt diet, glomerular filtration rate (GFR) was higher in ZDF than ZL rats. Autoregulation of GFR was less efficient and lithium clearance was lower in ZDF rats than ZL rats. Salt load reduced GFR in ZDF rats with restoration of lithium clearance and partial improvement in autoregulatory index (AI). The administration of 8-cyclopentyl-1,3-dipropylxanthine, a selective adenosine-1 receptor antagonist to ZDF rats on a high-salt diet abolished the improvement of AI in GFR. However, this effect was seen by neither (Cx40)GAP27 nor (Cx37,43)GAP27, which inhibits connexin (Cx) 40 or Cx37. Renal ANG II was higher in ZDF than ZL rats on normal salt diet, but the difference was eliminated by a salt load. The present data provide the first demonstration for a salt paradox in type 2 diabetes and implicate that in addition to Cx alterations, an enhanced proximal reabsorption attenuates TGF, underlying glomerular hyperfiltration and RAS activation. These data suggest that a high-salt diet standardizes distal delivery in diabetes, suppressing the RAS, and improving GFR autoregulation and hyperfiltration through adenosine.
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Affiliation(s)
- Tsuneo Takenaka
- Department of Nephrology and Community Health Science Center, Saitama Medical University, Iruma Saitama 350-0495 Japan.
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Vallon V, Thomson SC. Renal function in diabetic disease models: the tubular system in the pathophysiology of the diabetic kidney. Annu Rev Physiol 2012; 74:351-75. [PMID: 22335797 DOI: 10.1146/annurev-physiol-020911-153333] [Citation(s) in RCA: 251] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Diabetes mellitus affects the kidney in stages. At the onset of diabetes mellitus, in a subset of diabetic patients the kidneys grow large, and glomerular filtration rate (GFR) becomes supranormal, which are risk factors for developing diabetic nephropathy later in life. This review outlines a pathophysiological concept that focuses on the tubular system to explain these changes. The concept includes the tubular hypothesis of glomerular filtration, which states that early tubular growth and sodium-glucose cotransport enhance proximal tubule reabsorption and make the GFR supranormal through the physiology of tubuloglomerular feedback. The diabetic milieu triggers early tubular cell proliferation, but the induction of TGF-β and cyclin-dependent kinase inhibitors causes a cell cycle arrest and a switch to tubular hypertrophy and a senescence-like phenotype. Although this growth phenotype explains unusual responses like the salt paradox of the early diabetic kidney, the activated molecular pathways may set the stage for tubulointerstitial injury and diabetic nephropathy.
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Affiliation(s)
- Volker Vallon
- Department of Medicine, University of California San Diego, La Jolla, California 92093, USA.
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49
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Gorboulev V, Schürmann A, Vallon V, Kipp H, Jaschke A, Klessen D, Friedrich A, Scherneck S, Rieg T, Cunard R, Veyhl-Wichmann M, Srinivasan A, Balen D, Breljak D, Rexhepaj R, Parker HE, Gribble FM, Reimann F, Lang F, Wiese S, Sabolic I, Sendtner M, Koepsell H. Na(+)-D-glucose cotransporter SGLT1 is pivotal for intestinal glucose absorption and glucose-dependent incretin secretion. Diabetes 2012; 61:187-96. [PMID: 22124465 PMCID: PMC3237647 DOI: 10.2337/db11-1029] [Citation(s) in RCA: 504] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 10/19/2011] [Indexed: 12/15/2022]
Abstract
To clarify the physiological role of Na(+)-D-glucose cotransporter SGLT1 in small intestine and kidney, Sglt1(-/-) mice were generated and characterized phenotypically. After gavage of d-glucose, small intestinal glucose absorption across the brush-border membrane (BBM) via SGLT1 and GLUT2 were analyzed. Glucose-induced secretion of insulinotropic hormone (GIP) and glucagon-like peptide 1 (GLP-1) in wild-type and Sglt1(-/-) mice were compared. The impact of SGLT1 on renal glucose handling was investigated by micropuncture studies. It was observed that Sglt1(-/-) mice developed a glucose-galactose malabsorption syndrome but thrive normally when fed a glucose-galactose-free diet. In wild-type mice, passage of D-glucose across the intestinal BBM was predominantly mediated by SGLT1, independent the glucose load. High glucose concentrations increased the amounts of SGLT1 and GLUT2 in the BBM, and SGLT1 was required for upregulation of GLUT2. SGLT1 was located in luminal membranes of cells immunopositive for GIP and GLP-1, and Sglt1(-/-) mice exhibited reduced glucose-triggered GIP and GLP-1 levels. In the kidney, SGLT1 reabsorbed ∼3% of the filtered glucose under normoglycemic conditions. The data indicate that SGLT1 is 1) pivotal for intestinal mass absorption of d-glucose, 2) triggers the glucose-induced secretion of GIP and GLP-1, and 3) triggers the upregulation of GLUT2.
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Affiliation(s)
- Valentin Gorboulev
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Annette Schürmann
- Department of Experimental Diabetology, German Institute of Human Nutrition, Potsdam-Rehbruecke, Germany
| | - Volker Vallon
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Helmut Kipp
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Alexander Jaschke
- Department of Experimental Diabetology, German Institute of Human Nutrition, Potsdam-Rehbruecke, Germany
| | - Dirk Klessen
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Alexandra Friedrich
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Stephan Scherneck
- Department of Experimental Diabetology, German Institute of Human Nutrition, Potsdam-Rehbruecke, Germany
| | - Timo Rieg
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Robyn Cunard
- Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Maike Veyhl-Wichmann
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Aruna Srinivasan
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Daniela Balen
- Molecular Toxicology, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Davorka Breljak
- Molecular Toxicology, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Rexhep Rexhepaj
- Department of Physiology I, University of Tübingen, Tübingen, Germany
| | - Helen E. Parker
- Cambridge Institute for Medical Research, Addenbrooke’s Hospital, Cambridge, U.K
| | - Fiona M. Gribble
- Cambridge Institute for Medical Research, Addenbrooke’s Hospital, Cambridge, U.K
| | - Frank Reimann
- Cambridge Institute for Medical Research, Addenbrooke’s Hospital, Cambridge, U.K
| | - Florian Lang
- Department of Physiology I, University of Tübingen, Tübingen, Germany
| | - Stefan Wiese
- Department of Cell Morphology and Molecular Neurobiology, University of Bochum, Bochum, Germany
| | - Ivan Sabolic
- Molecular Toxicology, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Michael Sendtner
- Clinical Neurobiology, University of Würzburg, Würzburg, Germany
| | - Hermann Koepsell
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
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50
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Maric C, Hall JE. Obesity, metabolic syndrome and diabetic nephropathy. CONTRIBUTIONS TO NEPHROLOGY 2011; 170:28-35. [PMID: 21659755 DOI: 10.1159/000324941] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Diabetic nephropathy is becoming an increasingly important cause of morbidity and mortality worldwide owing to the increasing prevalence of type 2 diabetes, largely driven by increasing obesity. There is considerable evidence that obesity, hypertension and other elements of the metabolic syndrome also contribute to the progression of renal disease independent of diabetes. How they interact and contribute to diabetic nephropathy, however, is not completely understood. Clinical diabetic nephropathy is preceded by an increase in glomerular filtration rate, microalbuminuria and glomerular hypertrophy. Poor glycemic control and elevated systolic blood pressure exacerbate proteinuria and renal injury that may culminate in end-stage renal disease. A similar sequence of events may lead to obesity-related renal disease even in the absence of diabetes. This chapter compares and contrasts factors involved in the development of glomerular hemodynamic and kidney pathological processes associated with diabetes and obesity.
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