Fast blood-flow simulation for large arterial trees containing thousands of vessels

Blood flow modelling has previously been successfully carried out in arterial trees to study pulse wave propagation using nonlinear or linear flow solvers. However, the number of vessels used in the simulations seldom grows over a few hundred. The aim of this work is to present a computationally efficient solver coupled with highly detailed arterial trees containing thousands of vessels. The core of the solver is based on a modified transmission line method, which exploits the analogy between electrical current in finite-length conductors and blood flow in vessels. The viscoelastic behaviour of the arterial-wall is taken into account using a complex elastic modulus. The flow is solved vessel by vessel in the frequency domain and the calculated output pressure is then used as an input boundary condition for daughter vessels. The computational results yield pulsatile blood pressure and flow rate for every segment in the tree. This solver is coupled with large arterial trees generated from a three-dimensional constrained constructive optimisation algorithm. The tree contains thousands of blood vessels with radii spanning ~1 mm in the root artery to ~30 μm in leaf vessels. The computation takes seconds to complete for a vasculature of 2048 vessels and less than 2 min for a vasculature of 4096 vessels on a desktop computer.     

PolarCath cryoplasty enhances smooth muscle cell apoptosis in a rabbit iliac artery model: an experimental in vivo controlled study

Purpose

To in vivo investigate the histological response after single and double cryoplasty therapy in a rabbit iliac artery model.

Materials and methods

In total, 40 New Zealand White rabbits underwent percutaneous transluminal angioplasty of the iliac artery using either PolarCath balloon or a conventional angioplasty balloon of equal diameter. Arterial injury, inflammatory response and smooth muscle cells (SMC) apoptosis with the TUNEL (Terminal deoxynucleotidyl transferase dUTP Nick End Labeling) immunohistochemical assay were analyzed. Rabbits were divided between single or double balloon inflation and histological results were compared between cryoplasty and control angioplasty both at 30 min and 72 h.

Results

Arterial injury and wall inflammation scores were low and similar between cryoplasty and control groups after single and double balloon inflation. Compared to conventional balloon angioplasty, Polarcath cryoplasty demonstrated superior SMC apoptosis after single inflation at 30 min [12.0 ± 1.2 cells/(0.025 mm)2 vs 7.0 ± 1.5 cells/(0.025 mm)², p = 0.002], single inflation at 72 h [9.0 ± 1.0 cells/(0.025 mm)² vs 5.4 ± 1.4 cells/(0.025 mm)², p = 0.001], double inflation at 30 min [11.6 ± 1.5 cells/(0.025 mm)² vs 6.8 ± 1.4 cells/(0.025 mm)², p = 0.001] and double inflation at 72 h [9.2 ± 0.8 cells/(0.025 mm)² vs 5.0 ± 0.7 cells/(0.025 mm)², p = 0.001]. There were no significant differences in apoptosis between single and double cryoplasty application at 30 min and 72 h.

Conclusion

Cryoplasty demonstrated superior rates of SMC apoptosis at 30 min and 72 h and was associated to relatively low arterial injury and inflammation scores. An immediate second PolarCath inflation did not achieve superior apoptosis.     

三氧化二砷栓塞联合肝动脉介入治疗转移性肝癌的疗效并33 例 临床观察*

摘要目的：观察并探讨三氧化二砷碘油栓塞联合置管介入化疗治疗转移性肝癌的临床效果。方法：选取辽宁省肿瘤医院介入治 疗科2008-2010 年收治的转移性肝癌患者33 例,进行肝动脉造影及间接门脉造影,根据肝动脉造影或门脉造影结果,根据肝动脉 供血情况分别采取肝动脉化疗栓塞及肝动脉灌注化疗方法治疗,3-4 周为1 治疗周期,共完成4 个治疗周期,治疗结束后评价患 者临床有效率,随访半年、1 年、2 年患者生存率。结果：①介入治疗后,患者临床症状均改善,KPS得分明显高于化疗前（P＜ 0.05）,临床总有效率81.82%。②随访半年、1 年、2 年生存率分别为90.91%、66.67%、33.33%,肝动脉化疗栓塞组患者中远期生存 率明显高于肝动脉灌注化疗的患者。结论：三氧化二砷可从多角度抑制癌细胞,临床应用安全有效;对于不能手术和不适宜手术 的转移性肝癌患者,根据肝动脉供血情况和特点选择合适的介入治疗,可获得满意疗效。     

Intra-renal arterial injection of autologous bone marrow mesenchymal stromal cells ameliorates cisplatin-induced acute kidney injury in a rhesus Macaque mulatta monkey model

BackgroundClinically, acute kidney injury (AKI) is a potentially devastating condition for which no specific therapy improves efficacy of the repair process. Bone marrow mesenchymal stromal cells (BM-MSCs) are proven to be beneficial for the renal repair process after AKI in different experimental rodent models, but their efficacy in large animals and humans remains unknown. This study aims to assess the effect of autologous rhesus Macaque mulatta monkey BM-MSC transplantation in cisplatin-induced AKI.MethodsWe chose a model of AKI induced by intravenous administration of 5 mg/kg cisplatin. BM-MSCs were transplanted through intra-arterial injection. The animals were followed for survival, biochemistry analysis and pathology.ResultsTransplantation of 5 × 10⁶ cells/kg ameliorated renal function during the first week, as shown by significantly lower serum creatinine and urea values and higher urine creatinine and urea clearance without hyponatremia, hyperkalemia, proteinuria and polyuria up to 84 d compared with the vehicle and control groups. The superparamagnetic iron oxide nanoparticle-labeled cells were found in both the glomeruli and tubules. BM-MSCs markedly accelerated Foxp3+ T-regulatory cells in response to cisplatin-induced damage, as revealed by higher numbers of Foxp3+ cells within the tubuli of these monkeys compared with cisplatin-treated monkeys in the control and vehicle groups.ConclusionsThese data demonstrate that BM-MSCs in this unique large-animal model of cisplatin-induced AKI exhibited recovery and protective properties.     

姜黄素改善慢性肺动脉高压肺血管重塑作用途径的研究

目的：探究姜黄素改善慢性低O2高CO2大鼠肺动脉高压肺血管重塑作用途径的研究。方法：建立慢低O2高CO2肺血管重塑模型,以24只雄性大鼠为受试对象,随机分为四组（n=6）：I组（常氧空白对照组）,Ⅱ（低O2高CO2模型组）,Ⅲ组（色甘酸钠对照组）,Ⅳ组（姜黄素实验组）。将后3组动物放入常压低O2高CO2舱中,吸入O2浓度8％～11％,CO2浓度3％～5％,每天8h,每周6d,连续4周,Ⅲ组给予色甘酸钠以20mg／kg体重腹注射处理,Ⅳ组给予姜黄素混悬液按150mg/kg体重灌胃处理。光镜下、透射电镜下观察肺动脉血管壁及其周围大细胞超微结构形态学改变,甲苯胺蓝染色法和免疫组织化学法对肺动脉周围的肥大细胞及其脱颗粒状态进行性定量测定。结果：①电镜下,Ⅱ组肺细小动脉中膜平滑肌增生,外膜胶原纤维密集,内弹力板扭曲,内皮细胞起,血管外肥大细胞内颗粒减少,胞膜不完整;光镜下,Ⅱ组相比1组肺细小动脉管腔／管总面积（WA／TA）明显升（P〈0．05）、管腔／管总面积（EA／TA）明显降低（P〈0．05）,甲苯胺蓝染色肥大细胞细胞数（NMC）、肥大细胞脱颗率（DR）及免疫组化检测类胰蛋白酶阳性细胞数（TBS）高于I组（P〈0．05）;②干预后,电镜下,Ⅲ组、Ⅳ组血管结基本正常,平滑肌增生及胶原增生较Ⅱ组轻,肥大细胞膜完整;光镜下,两干预组相比Ⅱ组WA／TA明显降低（P〈0．05）、ET／TA明显升高（P〈0．05）,甲苯胺蓝染色NMC、DR、TBS阳性细胞数分别低于Ⅱ组（P〈0．05）。结论：姜素可通过Mc途径抑制慢性低O2高CO2导致的大鼠肺血管重塑改变。     

儿童颈髓区巨大动静脉畸形1例(英文)

脑动静脉畸形(AVM)是复杂的血管病变,是由于没有毛细血管床的脑动脉和静脉之间的异常连接引起的病灶[1]。脑动静脉畸形的临床表现有大出血、癫痫、神经功能障碍或头痛,但大部分患者无特异性症状,因此容易漏诊、误诊。手术切除、血管内治疗和放射治疗是动静脉畸形的选择疗法。血管内治疗可以作为其他难以治愈的脑动静脉畸形,或者作为手术切除或放射治疗前的辅助治疗,以减少脑动静脉畸形的血供或促进其收缩,进而促进手术切除或消融[2]。该病引起的颈部疼痛在儿科未见报道。我们收治1例颈髓区巨大动静脉畸形患儿,表现为持续性颈部疼痛并出现癫痫和呕吐症状,经采取分段外科胶栓塞术(第一次部分栓塞术后观察1年再行第二次栓塞),达到动静脉畸形的治愈。     

Modelling intravascular delivery from drug-eluting stents with biodurable coating: investigation of anisotropic vascular drug diffusivity and arterial drug distribution

In-stent restenosis occurs in coronary arteries after implantation of drug-eluting stents with non-uniform restenosis thickness distribution in the artery cross section. Knowledge of the spatio-temporal drug uptake in the arterial wall is useful for investigating restenosis growth but may often be very expensive/difficult to acquire experimentally. In this study, local delivery of a hydrophobic drug from a drug-eluting stent implanted in a coronary artery is mathematically modelled to investigate the drug release and spatio-temporal drug distribution in the arterial wall. The model integrates drug diffusion in the coating and drug diffusion with reversible binding in the arterial wall. The model is solved by the finite volume method for both high and low drug loadings relative to its solubility in the stent coating with varied isotropic–anisotropic vascular drug diffusivities. Drug release profiles in the coating are observed to depend not only on the coating drug diffusivity but also on the properties of the surrounding arterial wall. Time dependencies of the spatially averaged free- and bound-drug levels in the arterial wall on the coating and vascular drug diffusivities are discussed. Anisotropic vascular drug diffusivities result in slightly different average drug levels in the arterial wall but with very different spatial distributions. Higher circumferential vascular diffusivity results in more uniform drug loading in the upper layers and is potentially beneficial in reducing in-stent restenosis. An analytical expression is derived which can be used to determine regions in the arterial with higher free-drug concentration than bound-drug concentration.