title: Weight loss surgery improves the metabolic status in an obese rat model but does not affect bladder fibrosis associated with high fat diet feeding.
abstract: BACKGROUND
  Bladder dysfunction has one of the highest prevalences as a comorbidity of obesity in industrialized countries. The aetiopathogenesis of obesity-associated bladder dysfunction is still obscure, but there is growing evidence that general metabolic changes in obese patients may be in part responsible. As demonstrated recently, high fat diet (HFD) significantly alters the protein expression in the urinary bladder, activates multiple signalling pathways associated with cell survival and inflammation and ultimately provokes bladder fibrosis in an obese rat model. The study aimed to elucidate the role of matrix metalloproteases (MMPs) and their specific tissue inhibitors of metalloproteases (TIMPs) in obesity-related bladder extracellular matrix (ECM) remodelling and the effect of weight loss surgery via sleeve gastrectomy (SG) on phenotype and molecular parameters.
  
  
  METHODS
  Twenty-four male Sprague-Dawley rats were used for (i) characterization of the HFD phenotype and (ii) evaluation of alterations following SG. Metabolic status, the degree of bladder fibrosis and tissue expression and activity of MMP2, MMP9, MMP14, TIMP1 and TIMP2 were analysed by immunohistochemistry, enzyme-linked immunosorbent assay and activity assays. Statistical differences were calculated by analysis of variance or independent Student's t-test. A P-value <0.05 was considered statistically significant.
  
  
  RESULTS
  In HFD rats, we found significant alterations in lipid metabolism, fat mass, free fatty acid profile, insulin resistance and inflammatory markers. Voided volume was significantly decreased, and bladder showed marked fibrosis. MMPs and TIMPs were differentially regulated depending on animal status (controls, chow diet, HFD, and SG- and sham-operated animals) in both urothelium and detrusor smooth muscle. Although animal weight and most metabolic parameters were positively affected by SG, bladder fibrosis persisted. The limitations of this study were 1 month follow-up and lack of direct measurement of bladder function.
  
  
  CONCLUSIONS
  Early diagnosis of the bladder dysfunction associated with obesity is essential to allow targeted early intervention, that is, before manifestation of potentially irreversible ECM fibrotic alterations.
authors.affiliation: 1] Department of Cardiac Surgery, University Leipzig, Heart Center Leipzig, Leipzig, Germany [2] Integrated Research and Treatment Center (IFB) Adiposity Diseases, University of Leipzig, Leipzig, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Oberbach
authors.affiliation: 1] Integrated Research and Treatment Center (IFB) Adiposity Diseases, University of Leipzig, Leipzig, Germany [2] Department of Pediatric Surgery, University of Leipzig, Leipzig, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Schlichting
authors.affiliation: 1] Department of Cardiac Surgery, University Leipzig, Heart Center Leipzig, Leipzig, Germany [2] Integrated Research and Treatment Center (IFB) Adiposity Diseases, University of Leipzig, Leipzig, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Heinrich
authors.affiliation: Integrated Research and Treatment Center (IFB) Adiposity Diseases, University of Leipzig, Leipzig, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Lehmann
authors.affiliation: Department of Pediatric Surgery, Medical University of Graz, Medical School, Graz, Austria.
authors.forename: H
authors.initials: H
authors.lastname: Till
authors.affiliation: Department of Cardiac Surgery, University Leipzig, Heart Center Leipzig, Leipzig, Germany.
authors.forename: F W
authors.initials: FW
authors.lastname: Mohr
authors.affiliation: Department of Biomolecular Sciences, Section of Clinical Biochemistry and Cell Biology, University 'Carlo Bo', Urbino (PU), Italy.
authors.forename: F
authors.initials: F
authors.lastname: Mannello
authors.affiliation: Department of Urology, University of Leipzig, Leipzig, Germany.
authors.forename: J-U
authors.initials: JU
authors.lastname: Stolzenburg
authors.affiliation: Department of Urology, University of Leipzig, Leipzig, Germany.
authors.forename: J
authors.identifier: 0000000324846994
authors.initials: J
authors.lastname: Neuhaus
mesh_terms: D000818:Animals; D050110:Bariatric Surgery; D002478:Cells, Cultured; D059305:Diet, High-Fat / Q000009:adverse effects*; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005355:Fibrosis; D050356:Lipid Metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D009765:Obesity / Q000150:complications / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology / Q000601:surgery*; D051381:Rats; D017207:Rats, Sprague-Dawley; D001743:Urinary Bladder / Q000473:pathology*; D001745:Urinary Bladder Diseases / Q000201:enzymology / Q000209:etiology / Q000473:pathology* / Q000601:surgery; D015431:Weight Loss
chemical_list: D020782:Matrix Metalloproteinases