title: Mast cells are required for the development of renal fibrosis in the rodent unilateral ureteral obstruction model.
abstract: Mast cells are associated with inflammation and fibrosis. Whether they protect against or contribute to renal fibrosis is unclear. Based on our previous findings that mast cells can express and secrete active renin, and that angiotensin (ANG II) is profibrotic, we hypothesized that mast cells play a critical role in tubulointerstitial fibrosis. We tested this hypothesis in the 14-day unilateral ureteral obstruction (UUO) model in rats and mast cell-deficient (MCD) mice (WBB6F1-W/Wv) and their congenic controls (CC). In the 14-day UUO rat kidney, mast cell number is increased and they express active renin. Stabilizing mast cells in vivo with administration of cromolyn sodium attenuated the development of tubulointerstitial fibrosis, which was confirmed by measuring newly synthesized pepsin-soluble collagen and blind scoring of fixed trichrome-stained kidney sections accompanied by spectral analysis. Fibrosis was absent in UUO kidneys from MCD mice unlike that observed in the CC mice. Losartan treatment reduced the fibrosis in the CC UUO kidneys. The effects of mast cell degranulation and renin release were tested in the isolated, perfused kidney preparation. Mast cell degranulation led to renin-dependent protracted flow recovery. This demonstrates that mast cell renin is active in situ and the ensuing ANG II can modulate intrarenal vascular resistance in the UUO kidney. Collectively, the data demonstrate that mast cells are critical to the development of renal fibrosis in the 14-day UUO kidney. Since renin is present in human kidney mast cells, our work identifies potential targets in the treatment of renal fibrosis.
authors.affiliation: Dept. of Physiology and Biophysics, Weill Cornell Medical College, 1300 York Ave., Box 75, New York, NY 10065, USA.
authors.forename: Arul
authors.initials: A
authors.lastname: Veerappan
authors.forename: Alicia C
authors.initials: AC
authors.lastname: Reid
authors.forename: Nathan
authors.initials: N
authors.lastname: O'Connor
authors.forename: Rosalia
authors.initials: R
authors.lastname: Mora
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Brazin
authors.forename: Racha
authors.initials: R
authors.lastname: Estephan
authors.forename: Takashi
authors.initials: T
authors.lastname: Kameue
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Diane
authors.initials: D
authors.lastname: Felsen
authors.forename: Surya V
authors.initials: SV
authors.lastname: Seshan
authors.forename: Dix P
authors.initials: DP
authors.lastname: Poppas
authors.forename: Thomas
authors.initials: T
authors.lastname: Maack
authors.forename: Randi B
authors.initials: RB
authors.lastname: Silver
mesh_terms: D000804:Angiotensin II / Q000502:physiology; D000818:Animals; D015550:Cell Degranulation; D005355:Fibrosis; D006801:Humans; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D007674:Kidney Diseases / Q000188:drug therapy / Q000473:pathology*; D019808:Losartan / Q000627:therapeutic use; D008297:Male; D008407:Mast Cells / Q000502:physiology*; D051379:Mice; D051381:Rats; D012083:Renin / Q000502:physiology*; D012084:Renin-Angiotensin System / Q000502:physiology; D014517:Ureteral Obstruction / Q000473:pathology*
chemical_list: D000804:Angiotensin II; D012083:Renin; D019808:Losartan