Effects of diabetes mellitus, pressure overload and their association on myocardial structure and function.

• Type: Summary of Presentation in a National Conference
• Date: 2010

Authors

Falcão-Pires I (Author) FMUP; Gonçalves N (Author) FMUP; Moura C (Author) FMUP; Lamego I (Author) Other; Eloy C (Author) Other; Manuel-Lopes J (Author) Other; Areias JC (Author) FMUP; Leite-Moreira AF (Author) FMUP

Conference proceedings National

Title: Revista Portuguesa Cardiologia

Initial page: I-42

XXXI Congresso Português de Cardiologia

Lisboa, 09 a 12 de Abril de 2010

Scientific classification

FOS: Medical and Health sciences > Other medical sciences

CORDIS: Health sciences > Medical sciences > Medicine > Cardiology

Other information

Resumo (PT): 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 supra-renal aortic banding in rats. Sixweeks later, diabetes was induced by streptozotocin (65mg/kg, ip), resulting in 4 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, 10-8-10-5M). 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%), cardiomyocytes' 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%), AGEs deposition (DM=141±29%; DMBA= 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 (10-5M) increased 86.5±26.2% active tension, 105.3±20.2% dT/dtmax and 166.8±29.9% dT/dtmin. Similar effects were observed in BA and DM animals, while 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: Longstanding pressure-overload increased LV mass, while diabetes promoted AGEs 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.

Language: Portuguese

Type (Professor's evaluation): Scientific

Notes: XXXI Congresso Português de Cardiologia, publicado na Rev. Port. Cardiol. 2010; Vol.29(Supl.I):I-42.