title: Experimental mild renal insufficiency mediates early cardiac apoptosis, fibrosis, and diastolic dysfunction: a kidney-heart connection.
abstract: Impaired renal function with loss of nephron number in chronic renal disease (CKD) is associated with increased cardiovascular morbidity and mortality. However, the structural and functional cardiac response to early and mild reduction in renal mass is poorly defined. We hypothesized that mild renal impairment produced by unilateral nephrectomy (UNX) would result in early cardiac fibrosis and impaired diastolic function, which would progress to a more global left ventricular (LV) dysfunction. Cardiorenal function and structure were assessed in rats at 4 and 16 wk following UNX or sham operation (Sham); (n = 10 per group). At 4 wk, blood pressure (BP), aldosterone, glomerular filtration rate (GFR), proteinuria, and plasma B-type natriuretic peptide (BNP) were not altered by UNX, representing a model of mild early CKD. However, UNX was associated with significantly greater LV myocardial fibrosis compared with Sham. Importantly, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining revealed increased apoptosis in the LV myocardium. Further, diastolic dysfunction, assessed by strain echocardiography, but with preserved LVEF, was observed. Changes in genes related to the TGF-β and apoptosis pathways in the LV myocardium were also observed. At 16 wk post-UNX, we observed persistent LV fibrosis and impairment in LV diastolic function. In addition, LV mass significantly increased, as did LVEDd, while there was a reduction in LVEF. Aldosterone, BNP, and proteinuria were increased, while GFR was decreased. The myocardial, structural, and functional alterations were associated with persistent changes in the TGF-β pathway and even more widespread changes in the LV apoptotic pathway. These studies demonstrate that mild renal insufficiency in the rat results in early cardiac fibrosis and impaired diastolic function, which progresses to more global LV remodeling and dysfunction. Thus, these studies importantly advance the concept of a kidney-heart connection in the control of myocardial structure and function.
authors.affiliation: Cardiorenal Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic, 200 First St., SW, Rochester, MN 55905, USA. martin.fernando@mayo.edu
authors.forename: Fernando L
authors.initials: FL
authors.lastname: Martin
authors.forename: Paul M
authors.initials: PM
authors.lastname: McKie
authors.forename: Alessandro
authors.initials: A
authors.lastname: Cataliotti
authors.forename: S Jeson
authors.initials: SJ
authors.lastname: Sangaralingham
authors.forename: Josef
authors.initials: J
authors.lastname: Korinek
authors.forename: Brenda K
authors.initials: BK
authors.lastname: Huntley
authors.forename: Elise A
authors.initials: EA
authors.lastname: Oehler
authors.forename: Gerald E
authors.initials: GE
authors.lastname: Harders
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ichiki
authors.forename: Sarah
authors.initials: S
authors.lastname: Mangiafico
authors.forename: Karl A
authors.initials: KA
authors.lastname: Nath
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Redfield
authors.forename: Horng H
authors.initials: HH
authors.lastname: Chen
authors.forename: John C
authors.initials: JC
authors.lastname: Burnett
mesh_terms: D000818:Animals; D017209:Apoptosis; D005355:Fibrosis; D006321:Heart / Q000503:physiopathology*; D007668:Kidney / Q000473:pathology / Q000503:physiopathology; D008297:Male; D009206:Myocardium / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D051437:Renal Insufficiency / Q000150:complications* / Q000473:pathology* / Q000503:physiopathology; D018487:Ventricular Dysfunction, Left / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D020257:Ventricular Remodeling / Q000502:physiology
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