C-type natriuretic-peptide-potentiated relaxation response of gastric smooth muscle in streptozotocin-induced diabetic rats

AIM: To study the sensitivity of gastric smooth muscle to C-type natriuretic peptide (CNP) in streptozotocin (STZ)-induced diabetic rats. METHODS: The spontaneous contraction of a gastric smooth muscle strip was recorded by using physiological methods in rats. The expressions of CNP and natriuretic peptide receptor-B (NPR-B) in gastric tissue were examined by using immunohistochemistry techniques in the diabetic rat. RESULTS: At 4 wk after injection of STZ and vehicle, the frequency of spontaneous contraction of gastric smooth muscle was significantly reduced in diabetic rats, and the frequency was decreased from 3.10 ± 0.14 cycle/min in controls to 2.23 ± 0.13 cycle/min (n = 8, P < 0.01). However, the amplitude of spontaneous contraction was not significant different from the normal rat. CNP significantly inhibited spontaneous contraction of gastric smooth muscle in normal and diabetic rats, but the inhibitory effect was significantly potentiated in the diabetic rats. The amplitudes of spontaneous contraction were suppressed by 75.15% ± 0.71% and 58.92% ± 1.32% while the frequencies were decreased by 53.33% ± 2.03% and 26.95% ± 2.82% in diabetic and normal rats, respectively (n = 8, P < 0.01). The expression of CNP in gastric tissue was not changed in diabetic rats, however the expression of NPR-B was significantly increased in diabetic rats, and the staining indexes of NPR-B were 30.67 ± 1.59 and 17.63 ± 1.49 in diabetic and normal rat, respectively (n = 8, P < 0.01).CONCLUSION: The results suggest that CNP induced an inhibitory effect on spontaneous contraction of gastric smooth muscle, potentiated in diabetic rat via up-regulation of the natriuretic peptides-NPR-B-particulate guanylyl cyclase-cyclic GMP signal pathway.

Prognostic Potential of B - type Natriuetic Peptide and Quality of Life in Patients with Chronic Heart Failure

Objectives To study wheth- er change of BNP levels reflect the change of cardiac function and to investigate the short - term prognostic potential of BNP and QOL in patients with CHF. Methods 96 consecutive patients admittedwith CHF between September 2002 and January 2003 were stud- ied , upon entry the study, BNP levels were measured, Patients administered the disease - specificquality of life questionnaire Minnesota living with heart failure questionnaire (LiHFe) within 1 day. BNP levels and administering LiHFe were repeated three months later. Results BNP levels were increased proportional to the severity of cardiac function. Physical domain and total score of LiHFe were significantly correlated to the severity of CHF ( p < 0. 05 ). BNP levels were de- creased in improving group(p =0. 032) . In deteriora- ting group BNP levels increased (P = 0. 043 ) . Kaplan - meier analysis according to BNP level cutoff point 150 ng/1, the life curve of higher BNP level group was significantly lower than the lower group ( p = 0. 001 ) . In univariate logistic regression, NYHA class, BNP, LVEF, LVEDD, heart size, total score of LiHFe, phys- ical domain of LiHFe and the emotional domain of LiH- Fe were all significant prognostic factors of CHF ( p < 0. 05 for all). While in multiple regression, only BNP level( p = 0. 036) and the emotional domain of LiHFe ( p = 0. 025 ) were independent prognostic factors. Conclusions Change of BNP reflects the treatment efficacy of CHF. BNP and QOL are the two major short - time prognostic factors of the chronic heart failure patients.

Left atrial minimum volume by real-time three-dimensional echocardiography as an indicator of diastolic dysfunction

Background Left atrial （LA） maximum volume is becoming a prognostic biomarker for left ventricular （LV） diastolic dysfunction. However, we assessed LV diastolic function by measuring LA phasic volumes using real-time threedimensional echocardiography （RT3DE） in patients with stable coronary artery disease （CAD）. Methods Sixty-five stable CAD patients with normal LV ejection fraction （LVEF） were divided into three groups according to degree of coronary stenosis： control （n=15） with 〈50% stenosis as control group, mildS （n=25） with mild stenosis （50%- 70%） and severeS （n=25） with 〉70% stenosis. LA phasic volumes and function were evaluated and compared using RT3DE and two dimensional echocardiography （2DE）. N-terminal pro-B-type natriuretic peptide （NT-proBNP） levels were examined. The correlations of RT3DE-derived parameters with other conventional indices were analyzed. Results Significant correlations between RT3DE and 2DE for LA volume measurements were： control, r=0.93; mildS, 1=0.94; severeS, r=0.90 （all P 〈0.05）. Patients with severe coronary stenosis presented higher NT-proBNP level, indices of LA minimum volume and volume before atrial contraction, but lower LA total emptying fraction （LAEF） and LAEFpass^ve. Significant correlations of RT3DE derived LA volume indices with E/E＇ （r=0.695） and NF-proBNP （r=0.630） level were found. Conclusions RT3DE derived, LA indices correlate well with NT-proBNP level and may be superior to 2DE measurements for the evaluation of LV diastolic dysfunction. Enlargement of LA minimum volume in stable CAD patients without systolic dysfunction appears earlier and may be better correlated with LV diastolic function than that of LA maximum volume.