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Covington JD, Bray GA, Redman LM, Johannsen DL, Ravussin E. Eight weeks of dietary overfeeding increases renal filtration rates in humans: implications for the pathogenesis of diabetic hyperfiltration. J Intern Med 2015; 278:396-400. [PMID: 25903638 PMCID: PMC4560986 DOI: 10.1111/joim.12377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Diabetic nephropathy is characterized at its onset by glomerular hyperfiltration. Prospective studies in humans measuring filtration rates with weight gain are lacking. We investigated renal filtration following weight gain induced by overfeeding. DESIGN Eight weeks of overfeeding (40% above energy requirements, 44% fat, 15% protein and 41% carbohydrate) as well as a 6-month follow-up after the overfeeding intervention. SUBJECTS Thirty-five participants (age: 26.7 ±5.3 years; body mass index: 25.5 ± 2.2 kg m(-2) ; 29 m/6f). MEASUREMENTS Creatinine clearance rate (Ccr) from 24-h urine collection, estimated glomerular filtration rate (eGFR) from the modification of diet in renal disease (MDRD), insulin sensitivity/glucose disposal rate (GDR) by a euglycemic-hyperinsulinemic clamp, components from basic metabolic panels and serum lipid panels. RESULTS Both eGFR and Ccr increased with overfeeding (P = 0.04) and serum lipids (all P < 0.05), along with a decrease in insulin sensitivity (P = 0.003). Fasting glucose concentration was not affected (P = 0.98), but the per cent change in Ccr correlated positively with the change in GDR with overfeeding (r = 0.39, P = 0.02). Six months following overfeeding, serum glucose was maintained, and no evidence of urinary glucose was observed at any time-point. CONCLUSIONS These data suggest that renal hyperfiltration may act as a mechanism to preserve insulin sensitivity through maintenance of systemic glucose homoeostasis with caloric excess.
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Affiliation(s)
- J D Covington
- Laboratory of Human Physiology, Pennington Biomedical Research Center, Baton Rouge, LA, USA.,School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - G A Bray
- Laboratory of Human Physiology, Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - L M Redman
- Laboratory of Human Physiology, Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - D L Johannsen
- Laboratory of Human Physiology, Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - E Ravussin
- Laboratory of Human Physiology, Pennington Biomedical Research Center, Baton Rouge, LA, USA
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Maggiorani D, Dissard R, Belloy M, Saulnier-Blache JS, Casemayou A, Ducasse L, Grès S, Bellière J, Caubet C, Bascands JL, Schanstra JP, Buffin-Meyer B. Shear Stress-Induced Alteration of Epithelial Organization in Human Renal Tubular Cells. PLoS One 2015; 10:e0131416. [PMID: 26146837 PMCID: PMC4493045 DOI: 10.1371/journal.pone.0131416] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 06/02/2015] [Indexed: 12/14/2022] Open
Abstract
Tubular epithelial cells in the kidney are continuously exposed to urinary fluid shear stress (FSS) generated by urine movement and recent in vitro studies suggest that changes of FSS could contribute to kidney injury. However it is unclear whether FSS alters the epithelial characteristics of the renal tubule. Here, we evaluated in vitro and in vivo the influence of FSS on epithelial characteristics of renal proximal tubular cells taking the organization of junctional complexes and the presence of the primary cilium as markers of epithelial phenotype. Human tubular cells (HK-2) were subjected to FSS (0.5 Pa) for 48h. Control cells were maintained under static conditions. Markers of tight junctions (Claudin-2, ZO-1), Par polarity complex (Pard6), adherens junctions (E-Cadherin, β-Catenin) and the primary cilium (α-acetylated Tubulin) were analysed by quantitative PCR, Western blot or immunocytochemistry. In response to FSS, Claudin-2 disappeared and ZO-1 displayed punctuated and discontinuous staining in the plasma membrane. Expression of Pard6 was also decreased. Moreover, E-Cadherin abundance was decreased, while its major repressors Snail1 and Snail2 were overexpressed, and β-Catenin staining was disrupted along the cell periphery. Finally, FSS subjected-cells exhibited disappeared primary cilium. Results were confirmed in vivo in a uninephrectomy (8 months) mouse model where increased FSS induced by adaptive hyperfiltration in remnant kidney was accompanied by both decreased epithelial gene expression including ZO-1, E-cadherin and β-Catenin and disappearance of tubular cilia. In conclusion, these results show that proximal tubular cells lose an important number of their epithelial characteristics after long term exposure to FSS both in vitro and in vivo. Thus, the changes in urinary FSS associated with nephropathies should be considered as potential insults for tubular cells leading to disorganization of the tubular epithelium.
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Affiliation(s)
- Damien Maggiorani
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, France
- Université Toulouse III Paul Sabatier, Institute of Metabolic and Cardiovascular Diseases - I2MC, Toulouse, France
| | - Romain Dissard
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, France
- Université Toulouse III Paul Sabatier, Institute of Metabolic and Cardiovascular Diseases - I2MC, Toulouse, France
| | - Marcy Belloy
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, France
- Université Toulouse III Paul Sabatier, Institute of Metabolic and Cardiovascular Diseases - I2MC, Toulouse, France
| | - Jean-Sébastien Saulnier-Blache
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, France
- Université Toulouse III Paul Sabatier, Institute of Metabolic and Cardiovascular Diseases - I2MC, Toulouse, France
| | - Audrey Casemayou
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, France
- Université Toulouse III Paul Sabatier, Institute of Metabolic and Cardiovascular Diseases - I2MC, Toulouse, France
| | - Laure Ducasse
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, France
- Université Toulouse III Paul Sabatier, Institute of Metabolic and Cardiovascular Diseases - I2MC, Toulouse, France
| | - Sandra Grès
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, France
- Université Toulouse III Paul Sabatier, Institute of Metabolic and Cardiovascular Diseases - I2MC, Toulouse, France
| | - Julie Bellière
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, France
- Université Toulouse III Paul Sabatier, Institute of Metabolic and Cardiovascular Diseases - I2MC, Toulouse, France
| | - Cécile Caubet
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, France
- Université Toulouse III Paul Sabatier, Institute of Metabolic and Cardiovascular Diseases - I2MC, Toulouse, France
| | - Jean-Loup Bascands
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, France
- Université Toulouse III Paul Sabatier, Institute of Metabolic and Cardiovascular Diseases - I2MC, Toulouse, France
| | - Joost P. Schanstra
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, France
- Université Toulouse III Paul Sabatier, Institute of Metabolic and Cardiovascular Diseases - I2MC, Toulouse, France
| | - Bénédicte Buffin-Meyer
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Toulouse, France
- Université Toulouse III Paul Sabatier, Institute of Metabolic and Cardiovascular Diseases - I2MC, Toulouse, France
- * E-mail:
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The impact of hyperfiltration on the diabetic kidney. DIABETES & METABOLISM 2014; 41:5-17. [PMID: 25457474 DOI: 10.1016/j.diabet.2014.10.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 10/02/2014] [Accepted: 10/02/2014] [Indexed: 02/07/2023]
Abstract
More than two decades ago, hyperfiltration (HF) in diabetes was postulated to be a maladaptive response observed early in the course of diabetic kidney disease (DKD), which may eventually predispose to irreversible damage to nephrons and development of progressive renal disease. Despite this, the potential mechanisms leading to renal HF in diabetes are not fully understood, although several hypotheses have been proposed, including alterations in glomerular haemodynamic function and tubulo-glomerular feedback. Furthermore, the role of HF as a causative factor in renal disease progression is still unclear and warrants further prospective longer-term studies. Although HF has been entrenched as the first stage in the classic albuminuric pathway to end-stage renal disease in DKD, and HF has been shown to predict the progression of albuminuria in many, but not all studies, the concept that HF predisposes to the development of chronic kidney disease (CKD) stage 3, that is, glomerular filtration rate (GFR) decline to<60mL/min/1.73m(2), remains to be proved. Further long-term studies of GFR gradients therefore are required to establish whether HF ultimately leads to decreased kidney function, after adjustment for glycaemic control and other confounders. Whether reversal of HF with therapeutic agents is protective against reducing the risk of development of albuminuria and renal impairment is also worth investigating in prospective randomized trials.
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