Effects of Diabetes Mellitus, Pressure-Overload and Their Association on Myocardial Structure and Function

• Type: Article in International Scientific Journal
• Date: 2009

Authors

Falcao Pires, I (Author) Other; Goncalves, N (Author) Other; Moura, C (Author) Other; Lamego, I (Author) Other; Catarina Eloy (Author) FMDUP; Lopes, JM (Author) FMUP; Begieneman, MPV (Author) Other; Niessen, HWM (Author) Other; Areias JC (Author) FMUP; Leite-Moreira AF (Author) FMUP

Journal

Title: American Journal of Hypertension

Vol. 22 No. 11

Pages: 1190-1198

ISSN: 0895-7061

Publisher: Oxford University Press

Indexing

ISI Web of Knowledge - 11 Citations

Scopus - 13 Citations

Other information

Authenticus ID: P-003-EF9

DOI: 10.1038/ajh.2009.159

Abstract (EN): BACKGROUND Structural and functional changes involved in cardiac injury induced by diabetes mellitus, pressure-overload, or both conditions were evaluated. METHODS Pressure-overload was established by suprarenal aortic banding in rats. Six weeks later, diabetes was induced by streptozotocin (STZ, 65 mg/kg, intra peritoneally), resulting in four groups: SHAM, banded (BA), diabetic (DM), and diabetic-banded (DM-BA). On the 12th week, left ventricular LV) structure and function were evaluated. LV function was assessed in vivo with pressure-volume catheters and in vitro by papillary muscles' performance at baseline and in response to isoprenaline (ISO, 10(-8) to 10(-5) M). RESULTS Compared to SHAM, we observed a significant increase of type-B natriuretic peptide (BA = 370 +/- 110%; DM-BA = 580 +/- 210%), LV mass (BA = 36.8 +/- 3.6%; DM-BA 32.1 +/- 3.1%), cardiornyocyte diameter (BA = 19.5 +/- 2.3%; DM = 14.3 +/- 1.9%; DM-BA = 11.4 +/- 2.0%), fibrosis (BA = 85 +/- 14%; DM = 145 +/- 28%; DM-BA = 155 14%), advanced glycation endproduct (AGE) deposition(DM 141 +/- 29%; DM-BA = 166 +/- 46%), contraction (tAT: DM = 13.7 +/- 2.4%; DM-BA = 26.3 +/- 7.1%); a delayed relaxation (tHR: DM = 13.8 +/- 2.6%; DM-BA = 25.5 +/- 9.2%) and a decrease of Collagen type-I/type-III ratio (DM = -66.1 +/- 4.6%; DM-BA = -51.9 +/- 5.5). In SHAM animals, ISO (10(-5) M) increased 86.5 +/- 26.2% active tension, 105.3 +/- 20.2% dT/dt(max), and 166.8 +/- 29.9% dT/dt(min). Similar effects were observed in BA and DM animals, whereas in DM-BA these inotropic and lusitropic responses were blunted. Moreover, at a similar resting muscle length, ISO decreased passive tension by 12 +/- 3% in SHAM and 11 +/- 3% in BA, indicating an increase in myocardial distensibility, an effect that was absent in both diabetic groups. CONCLUSION Long-standing pressure-overload increased LV mass, while diabetes promoted AGE and Collagen deposition, which might explain the abolition of ISO-induced increased myocardial distensibility. Association of pressure-overload and diabetes completely blunted the inotropic and lusitropic responses to ISO, with no additional structural damages than in pressure-overload or diabetes alone. Am J Hypertens 2009; 22:1190-1198 (C) 2009 American Journal of Hypertension, Ltd.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9