title: Noninvasive and invasive evaluation of cardiac dysfunction in experimental diabetes in rodents.
abstract: BACKGROUND
  Because cardiomyopathy is the leading cause of death in diabetic patients, the determination of myocardial function in diabetes mellitus is essential. In the present study, we provide an integrated approach, using noninvasive echocardiography and invasive hemodynamics to assess early changes in myocardial function of diabetic rats.
  
  
  METHODS
  Diabetes was induced by streptozotocin injection (STZ, 50 mg/kg). After 30 days, echocardiography (noninvasive) at rest and invasive left ventricular (LV) cannulation at rest, during and after volume overload, were performed in diabetic (D, N = 7) and control rats (C, N = 7). The Student t test was performed to compare metabolic and echocardiographic differences between groups at 30 days. ANOVA was used to compare LV invasive measurements, followed by the Student-Newman-Keuls test. Differences were considered significant at P < 0.05 for all tests.
  
  
  RESULTS
  Diabetes impaired LV systolic function expressed by reduced fractional shortening, ejection fraction, and velocity of circumferential fiber shortening compared with that in the control group. The diabetic LV diastolic dysfunction was evidenced by diminished E-waves and increased A-waves and isovolumic relaxation time. The myocardial performance index was greater in diabetic compared with control rats, indicating impairment in diastolic and systolic function. The LV systolic pressure was reduced and the LV end-diastolic pressure was increased at rest in diabetic rats. The volume overload increased LVEDP in both groups, while LVEDP remained increased after volume overload only in diabetic rats.
  
  
  CONCLUSIONS
  These results suggest that STZ-diabetes induces systolic and diastolic dysfunction at rest, and reduces the capacity for cardiac adjustment to volume overload. In addition, it was also demonstrated that rodent echocardiography can be a useful, clinically relevant tool for the study of initial diabetic cardiomyopathy manifestations in asymptomatic patients.
authors.affiliation: Hypertension Unit, Heart Institute (INCOR), University of São Paulo, Medical School, São Paulo, Brazil. prof.rogeriowichi@usjt.br
authors.forename: Rogério
authors.initials: R
authors.lastname: Wichi
authors.forename: Christiane
authors.initials: C
authors.lastname: Malfitano
authors.forename: Kaleizu
authors.initials: K
authors.lastname: Rosa
authors.forename: Silvia B
authors.initials: SB
authors.lastname: De Souza
authors.forename: Vera
authors.initials: V
authors.lastname: Salemi
authors.forename: Cristiano
authors.initials: C
authors.lastname: Mostarda
authors.forename: Kátia
authors.initials: K
authors.lastname: De Angelis
authors.forename: Maria Claudia
authors.initials: MC
authors.lastname: Irigoyen
mesh_terms: D000818:Animals; D006328:Cardiac Catheterization; D009202:Cardiomyopathies / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D003921:Diabetes Mellitus, Experimental / Q000150:complications*; D003971:Diastole; D004195:Disease Models, Animal; D004452:Echocardiography; D006943:Hyperglycemia / Q000150:complications; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D017725:Ventricular Pressure