Characterizing valve dynamics in mice by high-resolution cine-MRI

AIMS

In calcific aortic valve disease (CAVD), progressive valvular sclerosis and calcification cause narrowing of the orifice and an impairment of the valve's function. We applied high-resolution cine-MRI to perform quantitative analysis of the dynamics of the aortic valve in a mice model of CAVD.

METHODS AND RESULTS

LDLr^-/- ApoB^100/100 mice were fed a Western diet (WD) or a standard diet (control) for 22 weeks. The mice were imaged in a 7 T horizontal MRI scanner, and aortic valve dynamics was examined by imaging the cross-section of the aorta at valve level using cine sequences. From these images, the area of the aortic valve orifice was determined during the heart cycle. MRI results were compared with echocardiographic and histopathologic results. The data revealed evidence of clear aortic valve dysfunction in WD mice as compared with control mice (interaction P < 0.001). MRI showed narrowing (14%, P < 0.05) of the orifice area, and this was also seen in histology (34%, P < 0.05), indicating more severe aortic stenosis after WD than in controls. Additionally, MRI revealed a reduction in the ejection fraction (EF) (-11%, P < 0.01), a result confirmed with echocardiography (-27%, P < 0.001) in mice fed with WD. EF detected by MRI and echocardiography also correlated strongly with the degree of stenosis assessed by histology.

CONCLUSIONS

Cine-MRI can be used for quantitative analysis of the aortic valve orifice over the cardiac cycle in mice. MRI showed the cusps clearly, and we were able to detect aortic valve dysfunction over time through the cardiac cycle.

Effects of flavonol-rich green tea cultivar (Camellia sinensis L.) on plasma oxidized LDL levels in hypercholesterolemic mice

To examine the possible benefits of tea flavonols, we compared anti-atherogenic effects between common and flavonol-rich tea cultivars. The tea infusion made from a flavonol-rich cultivar, but not a common cultivar, significantly decreased the plasma oxidized low-density lipoprotein level in mice fed a high-cholesterol diet. The result suggests that tea flavonols have the potential to protect against cardiovascular diseases.

A comparative study between Wuweizi seed and its post-ethanol extraction residue in normal and hypercholesterolemic mice

BACKGROUND

At the present, a shift from drug therapy, especially herbal therapy, to dietary supplementation is a trend in the management of dyslipidemia and related diseases. Therefore, the optimal utilization of herbal resource is important for a sustainable development of herbal medicine. Here, we compared the effects of dietary supplementation with Chinese medicine Schisandrae Chinensis Fructus seed (FSC-S) and the post-ethanol extraction residue of FSC-S (FSC-SpEt) on normal diet-fed (normal) and experimental hypercholesterolemic (HCL) mice.

METHODS

Male ICR mice (n = 10 in each group), weighing 17-21 g, were fed with normal diet (ND) or high cholesterol/bile salt (1/0.3 %, w/w) diet (HCBD) with or without supplemented with FSC-S, FSC-SpEt), or lipid-lowering agent fenofibrate (FF). Ten days later, serum/hepatic lipid and glucose (GLU) levels, body weight, organ/epididymal fat masses, and food/water intake were measured. Lipid level measurements included those of total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), HDL/LDL ratio, LDL/HDL ratio, and non-HDL (N-HDL).

RESULTS

Supplementation with FSC-S and FSC-SpEt increased serum TC (by 64 and 25 %, respectively) and LDL (by 60 and 27 %, respectively) in normal mice. FSC-S supplementation elevated serum TC, TG, HDL, LDL, and LDL/HDL ratio (up to 64, 118, 77, 197, and 51 %, respectively) in HCL mice. FSC-SpEt supplementation reduced serum TG (by 15 %) and LDL/HDL ratio (by 18 %), as well as increased serum HDL (by 22 %) and HDL/LDL ratio (by 21 %) in HCBD-fed mice. FSC-S decreased hepatic TC (by 19 %) contents and increased hepatic TG contents by 14 % in normal mice. FSC-S reduced hepatic GLU level in both normal and HCL mice by 24 and 22 %, respectively. Hepatic TC and TG contents were lowered in FSC-SpEt-supplemented normal mice by 16 and 20 %, respectively. The body/fatty masse and food intake were lowered, but the feed efficiency index (FEI), weight gain per unit of food ingested, was increased in FSC-S-supplemented normal and HCL mice. FF supplements reduced serum/hepatic lipids, hepatic GLU contents, and epididymal fat mass, but it induced hepatomegaly and high serum alanine aminotransferase (ALT) activity in normal and/or HCL mice.

CONCLUSION

The ensemble of results indicated that while FSC-SpEt supplementation is beneficial for the treatment of hyperlipidemia/fatty liver, FSC-S is potentially useful for the management of overweight/obesity.