Coronary Microembolization with Normal Epicardial Coronary Arteries and No Visible Infarcts on Nitrobluetetrazolium Chloride-Stained Specimens: Evaluation with Cardiac Magnetic Resonance Imaging in a Swine Model

Objective

To assess magnetic resonance imaging (MRI) features of coronary microembolization in a swine model induced by small-sized microemboli, which may cause microinfarcts invisible to the naked eye.

Materials and Methods

Eleven pigs underwent intracoronary injection of small-sized microspheres (42 µm) and catheter coronary angiography was obtained before and after microembolization. Cardiac MRI and measurement of cardiac troponin T (cTnT) were performed at baseline, 6 hours, and 1 week after microembolization. Postmortem evaluation was performed after completion of the imaging studies.

Results

Coronary angiography pre- and post-microembolization revealed normal epicardial coronary arteries. Systolic wall thickening of the microembolized regions decreased significantly from 42.6 ± 2.0% at baseline to 20.3 ± 2.3% at 6 hours and 31.5 ± 2.1% at 1 week after coronary microembolization (p < 0.001 for both). First-pass perfusion defect was visualized at 6 hours but the extent was largely decreased at 1 week. Delayed contrast enhancement MRI (DE-MRI) demonstrated hyperenhancement within the target area at 6 hours but not at 1 week. The microinfarcts on gross specimen stained with nitrobluetetrazolium chloride were invisible to the naked eye and only detectable microscopically. Increased cTnT was observed at 6 hours and 1 week after microembolization.

Conclusion

Coronary microembolization induced by a certain load of small-sized microemboli may result in microinfarcts invisible to the naked eye with normal epicardial coronary arteries. MRI features of myocardial impairment secondary to such microembolization include the decline in left ventricular function and myocardial perfusion at cine and first-pass perfusion imaging, and transient hyperenhancement at DE-MRI.     

基于荷瘤小鼠模型及生物信息学探讨燥湿解毒复方对胰腺癌的影响

目的 探讨燥湿解毒复方对小鼠胰腺癌细胞株皮下荷瘤生长的影响,并借助生物信息学判断该燥湿解毒复方治疗胰腺癌的潜在作用机制。方法 构建C57BL/6小鼠胰腺癌细胞株皮下荷瘤模型,将40只皮下荷瘤的小鼠随机分为高剂量给药组[27.82 g生药/(kg·d)],中等剂量给药组[13.91 g生药/(kg·d)],低剂量给药组[6.96 g生药/(kg·d)]以及正常对照组(给予磷酸盐缓冲液),每天灌胃1次,共21天。实验过程中观测小鼠体质量变化以及荷瘤体积变化并绘制肿瘤生长曲线,实验结束后测量各组瘤体质量并计算抑瘤率。利用BATMAN-TCM、STRING、GEPIA 2数据库判断该燥湿解毒复方针对胰腺癌的潜在治疗靶点及相关生物学通路,探索靶点分子对胰腺癌患者生存期的影响。结果 高剂量给药组和中等剂量给药组的小鼠肿瘤生长曲线较为平稳,低剂量给药组和对照组小鼠的肿瘤生长曲线则相对陡直。实验结束后测量发现高剂量给药组及中等剂量给药组小鼠瘤体质量分别为(0.16±0.08) g及(0.18±0.06) g,明显低于对照组小鼠瘤体质量(P<0.05)。高剂量给药组、中等剂量给药组及低剂量给药组抑瘤率分别为50.00%、43.75%和28.12%(P<0.05)。基于生物信息学分析燥湿解毒复方针对胰腺癌的潜在治疗靶点包括淀粉样前体蛋白(amyloid beta precursor protein,APP)、Polo样激酶1(Polo like kinase 1,PLK1)、过氧化物酶体增殖物激活受体γ(peroxisome proliferator activated receptor gamma,PPARG)、碳酸酐酶2(carbonic anhydrase 2,CA2)、表皮生长因子受体(epidermal growth factor receptor,EGFR)、维甲酸受体β(retinoic acid receptor beta,RARB)、神经降压素受体1(neurotensin receptor 1,NTSR1)和胸苷酸合成酶(thymidylate synthetase,TYMS)。这些靶点蛋白在人体内参与调节骨吸收、细胞对维生素A的反应、星形胶质细胞活化、对超氧阴离子的正向调节、苏氨酸磷酸化的调节、肝细胞再生、一碳代谢过程、RNA聚合酶Ⅱ对pri-miRNA转录的调控、柱状上皮细胞的发育等生物学过程。进一步分析发现,EGFR和PLK1的表达水平与胰腺癌患者的预后存在相关性。结论 根据小鼠胰腺癌细胞株皮下荷瘤模型及生物信息学结果,该燥湿解毒复方能抑制胰腺癌生长。     

The value of 18F‐FDG PET/CT in diagnosing and localising deep sternal wound infection to guide surgical debridement

Deep sternal wound infection (DSWI) is a severe complication in patients after open heart surgery (OHS). But there is a lack of appropriate imaging tool to detect the infection sites, which may lead to incomplete debridement. The present study aims to investigate the value of ¹⁸F‐fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F‐FDG PET/CT) in comparison with CT scan in diagnosing and localising DSWI. A total of 102 patients with DSWI after OHS were retrospectively collected from January 2012 to December 2017 in our hospital. All the patients had surgical debridements for DSWI with pretreatment imaging of either ¹⁸F‐FDG PET/CT or CT scan. The sensitivity, specificity, and accuracy of localising infection sites were compared between PET/CT and CT groups, with surgical, microbiological, and histopathological findings as the gold standard. The length of hospital stays and the rate of recurrence were also compared. Ten patients in the PET/CT group had a follow‐up PET/CT scan after debridement, and the correlations between the changes of PET/CT findings and surgical outcomes were analysed. ¹⁸F‐FDG PET/CT is more accurate than CT in diagnosing and localising DSWI after OHS, which leads to a more successful surgical debridement with a lower rate of recurrence and a shorter length of hospital stay. In addition, follow‐up PET/CT after debridement could evaluate the treatment effect.