Relationship between inflammation and progression of an abdominal aortic aneurysm in a rabbit model based on 18F-FDG PET/CT imaging.

OBJECTIVE: To explore the relationship between abdominal aortic aneurysm development and inflammation in the rabbit through the establishment of a rabbit infrarenal abdominal aortic aneurysm model and the use of 18F-FDG PET/CT imaging. METHODS: Twenty male New Zealand rabbits were administered an elastase intracavity perfusion to induce an infrarenal abdominal aortic aneurysm model. Prior to surgery, the rabbits underwent abdominal aorta ultrasonic testing and blood collection from the ear veins. Of the original 20 rabbits, 10 rabbits were euthanized two weeks after the operation following ultrasonic testing, PET/CT scanning and blood collection, and their arterial tissue samples were prepared for pathological and immunohistochemical staining. The remaining 10 rabbits were euthanized four weeks after the operation following ultrasonic testing, PET/CT scanning and blood collection, and the arterial tissue samples were prepared for pathological and immunohistochemical staining. RESULTS: Compared with the preoperative measurement, the maximum growth rate of the aneurysm diameter is 89.21 ± 0.02% (the absolute increase in diameter is 2.040 ± 0.376 mm) two weeks after the operation. Compared with the two-week postoperative value, the maximum growth rate of the aneurysm diameter is 15.8 ± 0.01% (the absolute increase in diameter is 0.684 ± 0.115 mm) four weeks after the operation. Compared with the preoperative values, the blood MMP-2 and MMP-9 levels significantly increase two weeks after surgery, P < 0.05. Compared with the two-week postoperative values, the blood MMP-2 and MMP-9 levels significantly decrease after four weeks post-surgery, P < 0.05. At two weeks after the operation, the SUVmax and the TBR of the 18F-FDG PET/CT of the AAA wall are 0.90 ± 0.03 and 1.19 ± 0.09, respectively. At four weeks after the operation, the SUVmax and the TBR of the 18F-FDG PET/CT of the AAA wall are 0.35 ± 0.05 and 1.15 ± 0.12, respectively. Compared with two weeks after the operation, the SUVmax significantly decreases at four weeks after the operation, P < 0.05. Compared with two weeks after the operation, there is no significant difference in the TBR at four weeks after the operation, P > 0.05. Immunohistochemical staining shows that the CD68-positive cell rate at four weeks after the operation significantly decreases ( P < 0.05) compared with the CD68-positive cell rate at two weeks after the operation. CONCLUSION: In the early stages of abdominal aortic aneurysm development, the inflammatory response of the arterial wall is significant, the local metabolic activity is strengthened, the SUVmax value of 18F-FDG is high, and the abdominal aortic aneurysm diameter experiences rapid growth. In the later stages of abdominal aortic aneurysm development, the diameter continues to increase; however, there are decreases in the wall inflammatory response, the local metabolic activity, and the SUVmax value of 18F-FDG. Thus, inflammation plays an important role in the early development of abdominal aortic aneurysm.

Can Platforms Affect the Safety and Efficacy of Drug-Eluting Stents in the Era of Biodegradable Polymers?: A Meta-Analysis of 34,850 Randomized Individuals.

OBJECTIVE: In the era of bare metal stents (BMSs), alloys have been considered to be better materials for stent design than stainless steel. In the era of biodegradable polymer drug-eluting stents (BP-DESs), the safety and efficacy of BP-DESs with different metal platforms (stainless steel or alloys) have not yet been reported, although their polymers are eventually absorbed, and only the metal platforms remain in the body. This study sought to determine the clinical safety and efficacy of BP-DESs with different platforms compared with other stents (other DESs and BMSs). METHODS: PubMed, Embase and Clinical Trials.gov were searched for randomized controlled trials (RCTs) that compared BP-DESs with other stents. After performing pooled analysis of BP-DESs and other stents, we performed a subgroup analysis using two classification methods: stent platform and follow-up time. The study characteristics, patient characteristics and clinical outcomes were abstracted. RESULTS: Forty RCTs (49 studies) comprising 34,850 patients were included. Biodegradable polymer stainless drug-eluting stents (BP-stainless DESs) were superior to the other stents [mainly stainless drug-eluting stents (DESs)] in terms of pooled definite/probable stent thrombosis (ST) (OR [95% CI] = 0.76[0.61-0.95], p = 0.02), long-term definite/probable ST (OR [95% CI] = 0.73[0.57-0.94], p = 0.01), very late definite/probable ST (OR [95% CI] = 0.56[0.33-0.93], p = 0.03) and long-term definite ST. BP-stainless DESs had lower rates of pooled, mid-term and long-term target vessel revascularization (TVR) and target lesion revascularization (TLR) than the other stainless DESs and BMSs. Furthermore, BP-stainless DESs were associated with lower rates of long-term death than other stainless DESs and lower rates of mid-term myocardial infarction than BMSs. However, only the mid-term and long-term TVR rates were superior in BP-alloy DESs compared with the other stents. CONCLUSION: Our results indirectly suggest that BP-stainless DESs may offer more benefits than BP-alloy DESs in the era of BP-DESs. Further well-designed RCTs comparing BP-stainless with BP-alloy DESs are needed to confirm which platform is better.

Plaque Thrombosis is Reduced by Attenuating Plaque Inflammation with Pioglitazone and is Evaluated by Fluorodeoxyglucose Positron Emission Tomography.

INTRODUCTION: The relationship between the beneficial effects of pioglitazone in reducing clinical events and plaque inflammatory burden remains unknown. This study aimed to determine whether pioglitazone can reduce the number of plaque thrombosis incidences and whether decreasing plaque inflammation is the mechanism by which pioglitazone reduces plaque thromboses. METHODS AND RESULTS: therosclerotic rabbits were divided into two groups: the atherosclerosis group (n = 13) and pioglitazone group (n = 10). The rabbits underwent pharmacological triggering to induce thrombosis. Serum inflammatory markers, FDG uptake, macrophage, and neovessel staining detected arterial inflammation. PET/CT scans were performed twice (baseline and posttreatment scans). Plaque area, macrophages, and neovessels were measured and the histologic sections were matched with the PET/CT scans. Serum MMP-9 and hsCRP were lower in the pioglitazone group compared to the atherosclerosis group. The SUVmean significantly decreased in the pioglitazone group (0.62 ± 0.21 vs. 0.55 ± 0.19, P = 0.008), but increased in the atherosclerosis group (0.61 ± 0.15 vs. 0.91 ± 0.20, P < 0.000). The incidence rate of plaque rupture, plaque area, macrophage density, and neovessel density was significantly lower in rabbits with pioglitazone than without (15% vs. 38%, P < 0.001; 18.00 ± 2.30 vs. 27.00 ± 1.60; P < 0.001; 8.80 ± 3.94 vs. 28.26 ± 2.49; P < 0.001; 16.50 ± 3.09 vs. 29.00 ± 2.11; P < 0.001, respectively). Moreover, plaque area and macrophage density were positively correlated with SUV values. CONCLUSIONS: Our study suggests that pioglitazone can reduce the number of plaque thrombosis incidences by decreasing plaque inflammation. (18)F-FDG-PET/CT can detect plaque inflammation and assess the effects of antiatherosclerotic drugs.