Regular transient limb ischemia prevents atherosclerosis progression in hypercholesterolemic rabbits

Regular transient limb ischemia improves endothelial function and inhibits endothelial cell apoptosis to prevent atherosclerosis in rabbit

AIMS

Regular transient limb ischemia (RTLI) can prevent atherosclerosis (AS) progression in hypercholesterolemic rabbits. This study aimed to investigate the minimum effective intensity and possible mechanisms of RTLI for preventing atherosclerosis.

METHODS

Eighty rabbits were divided into eight groups: normal (N), high cholesterol (H), three RTLI [three RTLI cycles every other day (R3qod), three RTLI cycles daily (R3qd), and six RTLI cycles daily (R6qd), each cycle of RTLI included 5 min of limb ischemia followed by 5 min limb reperfusion], and three correlated sham RTLI [sham ischemia for 30 min once every other day (S3qod), sham ischemia for 30 min once daily (S3qd), and sham ischemia for 60 min once daily (S6qd)]. Rabbits in group N were kept normally, while the others were fed 1% cholesterol diet for 12 weeks. The RTLI and sham RTLI groups were received RTLI or sham RTLI procedure, respectively. The plaque area in the thoracic aorta was determined by oil red O staining, and quantifying the ratio of plaque area to intimal area (PA/IA). Endothelium-dependent and -independent relaxation were also determined. Endothelial cell were isolated from abdominal aorta of rabbits, and the apoptosis ratio was detected using flow cytometry.

RESULTS

The PA/IA and early apoptotic cell ratio was significantly lower as well as the endothelium-dependent relaxation response was higher in group R6qd than those in groups H and S6qd, while those in the R3qod group was not significantly different from those in groups H and S3qod, as well as those in the R3qd group showed no significant difference compared to those in groups H and S3qd.

CONCLUSIONS

Six cycles of RTLI daily was the optimal effective intensity to prevent AS progression in rabbits. Endothelial function improvement and apoptosis inhibition might contribute to the anti-AS effects.

Regular transient limb ischemia protects endothelial function against hypercholesterolemic damage in rabbits

Regular transient limb ischemia (RTLI) can prevent atherosclerosis in hypercholesterolemic rabbits. As endothelial dysfunction is the initial factor leading to atherosclerosis, we investigated the effect of RTLI on endothelial function in hypercholesterolemic rabbits. We randomly allocated 15 New Zealand white rabbits to three groups, five animals per group: the hypercholesterolemic group (Group H), the sham RTLI group (Group S), and the RTLI group (Group L). All rabbits received hypercholesterolemic fodder daily. No intervention was performed on the rabbits in Group H. Rabbits in Group S were kept in hutches, with a deflated cuff applied to their left hind limb for 60 min every day. For rabbits in Group L, RTLI (six cycles of 5-min ischemia and 5-min reperfusion of the left hind limb) was applied once daily for 12 weeks. At the end of week 12, a segment of the abdominal aorta was isolated from each rabbit for in vitro measurement of the endothelium-dependent vasodilation (EDV) response to different concentrations of acetylcholine and the endothelium-independent vasodilation (EIV) response to sodium nitroprusside. The EDV response was significantly higher in Group L than in Groups S and H (p < 0.05), with no significant difference between Groups S and H (p > 0.05). There was no difference in the EIV response among the three groups. RTLI could improve the EDV response, protecting endothelial function against hypercholesterolemic damage.

Long-term results of extensive aortoiliac occlusive disease (EAIOD) treated by endovascular therapy and risk factors for loss of primary patency

Background:

Although endovascular therapy has been widely used for focal aortoiliac occlusive disease (AIOD), its performance for extensive AIOD (EAIOD) is not fully evaluated. We aimed to demonstrate the long-term results of EAIOD treated by endovascular therapy and to identify the potential risk factors for the loss of primary patency.

Methods:

Between January 2008 and June 2018, patients with a clinical diagnosis of the 2007 TransAtlantic Inter-Society Consensus II (TASC II) C and D AIOD lesions who underwent endovascular treatment in our institution were enrolled. Demographic, diagnosis, procedure characteristics, and follow-up information were reviewed. Univariate analysis was used to identify the correlation between the variables and the primary patency. A multivariate logistic regression model was used to identify the independent risk factors associated with primary patency. Five- and 10-year primary and secondary patency, as well as survival rates, were calculated by Kaplan-Meier analysis.

Results:

A total of 148 patients underwent endovascular treatment in our center. Of these, 39.2% were classified as having TASC II C lesions and 60.8% as having TASC II D lesions. The technical success rate was 88.5%. The mean follow-up time was 79.2 ± 29.2 months. Primary and secondary patency was 82.1% and 89.4% at 5 years, and 74.8% and 83.1% at 10 years, respectively. The 5-year survival rate was 84.2%. Compared with patients without loss of primary patency, patients with this condition showed significant differences in age, TASC II classification, infrainguinal lesions, critical limb ischemia (CLI), and smoking. Multivariate logistic regression analysis showed age <61 years (adjusted odds ratio [aOR]: 6.47; 95% CI: 1.47–28.36; P = 0.01), CLI (aOR: 7.81; 95% CI: 1.92–31.89; P = 0.04), and smoking (aOR: 10.15; 95% CI: 2.79–36.90; P < 0.01) were independent risk factors for the loss of primary patency.

Conclusion:

Endovascular therapy was an effective treatment for EAIOD with encouraging patency and survival rate. Age <61 years, CLI, and smoking were independent risk factors for the loss of primary patency.