ABSTRACT
Despite the importance of translational medicine in cardiovascular research, rat vascular endothelial function and sympathetic activity assessment remains challenging.This study consisted of two parts: part A examined the consistency of reactive hyperemia-elicited dilatation index(DI) before (DI Original ) and after (DI EEMD ) ensemble empirical mode decomposition (EEMD) using Wistar-Kyoto (WKY)rats (n = 7). Part B compared the endothelial function and heart rate variability of normal WKY rats (group 1, n = 9)with those of spontaneously hypertensive rats (group 2,n = 9) at two time points of development. The SD1/SD2 ratio(SSR) was obtained from Poincaré plot analysis to evaluate sympathetic activities. Using a Bland-Altman plot, part A of the study demonstrated a lower agreement of DI Original than that of DI EEMD . In part B, despite no significant difference in DI EEMD between the two groups at age 10 weeks, DI EEMD was higher in group 1 (2.25 } 0.63 vs. 1.43 } 0.41 for groups 1 and 2, respectively, p = 0.004) at 20 weeks. Although no notable change in SSR existed in group 1 between the twotime points, a significant difference existed in group 2(p < 0.001). In conclusion, using algorithms of Poincaré plot analysis and EEMD, the impact of age and hypertension on rat vascular endothelial function and heart rate variability can be reliably assessed.
Subject(s)
Autonomic Nervous System/physiopathology , Diagnosis, Computer-Assisted/methods , Electrocardiography/methods , Endothelium, Vascular/physiopathology , Hypertension/diagnosis , Hypertension/physiopathology , Photoplethysmography/methods , Algorithms , Animals , Blood Pressure , Blood Volume , Heart Rate , Male , Rats , Rats, Inbred SHR , Rats, Inbred WKY , Reproducibility of Results , Sensitivity and Specificity , Signal Processing, Computer-AssistedABSTRACT
GOALS: This study was conducted to explore the association between nonalcoholic fatty liver disease and glucose metabolism as well as insulin resistance using the homeostasis model assessment method (HOMA). STUDY: From July 2003 to June 2004, 23 patients with ultrasound-proved fatty liver and either normal (10 patients) or abnormal (13 patients) serum aminotransferase levels were enrolled. Blood tests included a routine biochemistry, a 75-g glucose oral glucose tolerance test (OGTT) with blood sampled at 30-minute intervals during a 120-minute period. Fasting and 120-minute serum leptin, insulin, and C-peptide concentrations were also measured. RESULTS: Using the Mann-Whitney U test, significant differences were found in gamma glutamyl transpeptidase (28.6+/-7.9 vs. 65.1+/-65.9 U/L, P=0.008), fasting insulin (FI) (13.11+/-7.53 vs. 31.76+/-42.95 muU/mL, P=0.02), fasting C-peptide (3.82+/-3.00 vs. 2.17+/-0.43 ng/mL, P=0.01), fasting leptin (10.34+/-4.05 vs. 24.27+/-24.97 ng/mL, P=0.01), HOMA-IR (3.34+/-1.06 vs. 8.81+/-13.18, P=0.02), and HOMA beta-cell function (120.32+/-52.50 vs. 242.20+/-247.29, P=0.02) between normal and abnormal ALT/AST function groups. From the 75-g OGTT, no significant difference of plasma glucose was noted at 0, 30, 60, and 90 minutes but significant change was noted in 120-minute plasma glucose (99.3+/-21.5 vs. 131.4+/-27.3 mg/dL, P=0.004) of 2 groups. CONCLUSIONS: In conclusion, patients with fatty liver proved by ultrasound sonography might be at high risk of developing type 2 diabetes, especially when they had elevated liver enzymes. OGTT is warranted for the early diagnosis of these high risk patients.
