A predictive microfluidic model of human glioblastoma to assess trafficking of blood–brain barrier-penetrant nanoparticles

The blood–brain barrier represents a significant challenge for the treatment of high-grade gliomas, and our understanding of drug transport across this critical biointerface remains limited. To advance preclinical therapeutic development for gliomas, there is an urgent need for predictive in vitro models with realistic blood–brain-barrier vasculature. Here, we report a vascularized human glioblastoma multiforme (GBM) model in a microfluidic device that accurately recapitulates brain tumor vasculature with self-assembled endothelial cells, astrocytes, and pericytes to investigate the transport of targeted nanotherapeutics across the blood–brain barrier and into GBM cells. Using modular layer-by-layer assembly, we functionalized the surface of nanoparticles with GBM-targeting motifs to improve trafficking to tumors. We directly compared nanoparticle transport in our in vitro platform with transport across mouse brain capillaries using intravital imaging, validating the ability of the platform to model in vivo blood–brain-barrier transport. We investigated the therapeutic potential of functionalized nanoparticles by encapsulating cisplatin and showed improved efficacy of these GBM-targeted nanoparticles both in vitro and in an in vivo orthotopic xenograft model. Our vascularized GBM model represents a significant biomaterials advance, enabling in-depth investigation of brain tumor vasculature and accelerating the development of targeted nanotherapeutics.

High-grade gliomas are the most common primary malignant brain tumors in adults (1). These include grade IV astrocytomas, commonly known as glioblastoma multiforme (GBM), which account for more than 50% of all primary brain cancers and have dismal prognoses, with a 5-y survival rate of less than 5% (2). Due to their infiltrative growth into the healthy brain tissue, surgery often fails to eradicate all tumor cells (3). While chemotherapy and radiation modestly improve median survival (4), most patients ultimately succumb to their tumors. This is primarily due to the presence of a highly selective and regulated endothelium between blood and brain parenchyma known as the blood–brain barrier (BBB) (5), which limits the entry of therapeutics into the brain tissue where tumors are located. The BBB, characterized by a unique cellular architecture of endothelial cells (ECs), pericytes (PCs), and astrocytes (ACs) (6, 7), displays up-regulated expression of junctional proteins and reduced paracellular and transcellular transports compared to other endothelia (8). While this barrier protects the brain from toxins and pathogens, it also severely restricts the transport of many therapeutics, as evidenced by the low cerebrospinal fluid (CSF)-to-plasma ratio of most chemotherapeutic agents (9). There is thus an important need to develop new delivery strategies to cross the BBB and target tumors, enabling sufficient drug exposure (10).Despite rigorous research efforts to develop effective therapies for high-grade gliomas, the majority of trialed therapeutics have failed to improve outcomes in the clinic, even though the agents in question are effective against tumor cells in preclinical models (11). This highlights the inability of current preclinical models to accurately predict the performance of therapeutics in human patients. To address these limitations, we developed an in vitro microfluidic model of vascularized GBM tumors embedded in a realistic human BBB vasculature. This BBB-GBM platform features brain microvascular networks (MVNs) in close contact with a GBM spheroid, recapitulating the infiltrative properties of gliomas observed in the clinic (12) and those of the brain tumor vasculature, with low permeability, small vessel diameter, and increased expression of relevant junctional and receptor proteins (7). This platform is well suited for quantifying vascular permeability of therapeutics and simultaneously investigating modes of transport across the BBB and into GBM tumor cells.There is strong rationale for developing therapeutic nanoparticles (NPs) for GBM and other brain tumors, as they can be used to deliver a diverse range of therapeutic agents and, with appropriate functionalization, can be designed to exploit active transport mechanisms across the BBB (13, 14). Liposomal NPs have been employed in the oncology clinic to improve drug half-life and decrease systemic toxicity (15), but, to date, no nanomedicines have been approved for therapeutic indications in brain tumors. We hypothesize that a realistic BBB-GBM model composed entirely of human cells can accelerate preclinical development of therapeutic NPs. Using our BBB-GBM model, we investigated the trafficking of layer-by-layer NPs (LbL-NPs) and ultimately designed a GBM-targeted NP. The LbL approach leverages electrostatic assembly to generate modular NP libraries with highly controlled architecture. We have used LbL-NPs to deliver a range of therapeutic cargos in preclinical tumor models (16, 17) and have recently demonstrated that liposomes functionalized with BBB-penetrating ligands improved drug delivery across the BBB to GBM tumors (18). Consistent with clinical data (19), we observed that the low-density lipoprotein receptor-related protein 1 (LRP1) was up-regulated in the vasculature near GBM spheroids in the BBB-GBM model and leveraged this information to design and iteratively test a library of NPs. We show that the incorporation of angiopep-2 (AP2) peptide moieties on the surface of LbL-NPs leads to increased BBB permeability near GBM tumors through LRP1-mediated transcytosis. With intravital imaging, we compared the vascular permeabilities of dextran and LbL-NPs in the BBB-GBM platform to those in mouse brain capillaries and validated the predictive potential of our in vitro model. Finally, we show the capability of the BBB-GBM platform to screen therapeutic NPs and predict in vivo efficacy, demonstrating improved efficacy of cisplatin (CDDP) when encapsulated in GBM-targeting LbL-NPs both in vitro and in vivo.     

Clinical and Metabolomic Effects of Lactiplantibacillus plantarum and Pediococcus acidilactici in Fructose Intolerant Patients

Fructose intolerance (FI) is a widespread non-genetic condition in which the incomplete absorption of fructose leads to gastro-intestinal disorders. The crucial role of microbial dysbiosis on the onset of these intolerance symptoms together with their persistence under free fructose diets are driving the scientific community towards the use of probiotics as a novel therapeutic approach. In this study, we evaluated the prevalence of FI in a cohort composed of Romanian adults with Functional Grastrointestinal Disorders (FGIDs) and the effectiveness of treatment based on the probiotic formulation EQBIOTA^® (Lactiplantibacillus plantarum CECT 7484 and 7485 and Pediococcus acidilactici CECT 7483). We evaluated the impact of a 30-day treatment both on FI subjects and healthy volunteers. The gastrointestinal symptoms and fecal volatile metabolome were evaluated. A statistically significant improvement of symptoms (i.e., bloating, and abdominal pain) was reported in FI patient after treatment. On the other hand, at the baseline, the content of volatile metabolites was heterogeneously distributed between the two study arms, whereas the treatment led differences to decrease. From our analysis, how some metabolomics compounds were correlated with the improvement and worsening of clinical symptoms clearly emerged. Preliminary observations suggested how the improvement of gastrointestinal symptoms could be induced by the increase of anti-inflammatory and protective substrates. A deeper investigation in a larger patient cohort subjected to a prolonged treatment would allow a more comprehensive evaluation of the probiotic treatment effects.     

白蛋白和免疫球蛋白检测在神经系统疾病诊断中的临床应用

目的探讨免疫球蛋白(Ig)和白蛋白(Alb)检测在神经系统疾病诊断中的应用价值。方法以16例非神经系统疾病为对照组,用散射光比浊法测定137例神经系统疾病患者脑脊液与血清中免疫球蛋白(IgG、IgA、IgM)和白蛋白的含量,通过Protis分析软件计算免疫球蛋白商值(QIg)、白蛋白商值(QAlb)和IgG指数,用以判断血脑屏障(BBB)功能状态及免疫球蛋白鞘内合成情况。结果1.正常组QAlb、QIgG、IgA和IgM分别为(4.3±1.4)、(2.1±0.8)、(1.2±0.6)、(0.3±0.2),与单纯BBB损害组和BBB损害伴有鞘内Ig合成组比较,三者差别具有统计学意义(P<0.05);2.单纯鞘内Ig合成组QAlb为(4.08±1.48),与正常组比较差异无统计学意义(P>0.05);3.单纯鞘内Ig合成组QIgA、QIgM值与正常组差别具有统计学意义(P<0.05),QIgG与正常组比较无统计学意义(P>0.05)。4.在正常组IgG指数为(4.7±1.2),与BBB损害伴有鞘内Ig合成组及单纯鞘内Ig合成组比较差别具有统计学意义(P<0.05),与单纯BBB损害组比较无统计学意义(P>0.05)。结论不同神经系统疾病BBB功能障碍发生频率、BBB损害程度、鞘内Ig合成类型及蛋白商值不同,因此,免疫球蛋白和白蛋白检测能够为某些神经系统疾病提供诊断及鉴别诊断依据。     

IL-33对特应性皮炎患者ST2-ILC2s轴及皮肤屏障影响的研究进展

特应性皮炎(AD)是目前最常见、反复发作、对生活质量影响较大的免疫性皮肤病之一.IL-33是IL-1家族成员之一,上皮细胞会因机械创伤、细菌和外源性蛋白酶等触发因素释放IL-33,IL-33通过长型血清刺激因子-2(ST2)和多种细胞上的IL-1受体附件结合,并激活第2组固有淋巴细胞(ILC2s)、Th2细胞、肥大细胞...     

Antibacterial and Biodegradable Polysaccharide-Based Films for Food Packaging Applications: Comparative Study

One of the major objectives of food industry is to develop low-cost biodegradable food packaging films with optimal physicochemical properties, allowing for their large-scale production and providing a variety of applications. To meet the expectations of food industry, we have fabricated a series of solution-cast films based on common biodegradable polysaccharides (starch, chitosan and alginate) to be used in food packaging applications. Selected biopolymers were modified by the addition of glycerol and oxidized sucrose (starch), glycerol (chitosan), and glycerol and calcium chloride (alginate), as well as being used to form blends (starch/chitosan and starch/alginate, respectively). A chestnut extract was used to provide antibacterial properties to the preformed materials. The results of our studies showed that each modification reduced the hydrophilic nature of the polymers, making them more suitable for food packaging applications. In addition, all films exhibited much higher barrier properties to oxygen and carbon dioxide than commercially available films, such as polylactic acid, as well as exhibiting antimicrobial properties against model Gram-negative and Gram-positive bacteria (Escherichia coli and Staphylococcus epidermidis, respectively), as well as yeast (Candida albicans).     

孕酮对大鼠脑缺血再灌注后脑水肿的影响

目的观察孕酮对脑缺血后脑水肿的影响,并从孕酮对血-脑屏障通透性的影响和抗氧自由基两方面进一步探讨其可能的作用机制。方法雄性SD大鼠72只随机分为假手术组、I／R组、孕酮组。进行脑组织含水量测定,伊文思蓝渗透法血-脑屏障通透性定量分析,电镜下血-脑屏障超微结构形态学观察,脑组织SOD活性和MDA含量测定。结果孕酮能明显减轻脑水肿,降低血-脑屏障通透性,抑制SOD活性的降低和MDA含量的增高。结论孕酮抑制氧自由基的损害,降低血-脑屏障通透性,减轻脑缺血后脑水肿。     

Protective effect of glutamine-enriched early enteral nutrition on intestinal mucosal barrier injury after liver transplantation in rats

Background

The effect of glutamine-enriched early enteral nutrition (Gln-EEN) on intestinal mucosal barrier injury after liver transplantation (LT) remains uncertain.

Methods

The Wistar-to-Wistar rat LT model was used to explore the protective effect of Gln-EEN. Morphologic changes of intestinal mucosa, levels of intestinal malondialdehyde and secretory immunoglobulin (sIgA), plasma endotoxin, D-lactic acid, serum tumor necrosis factor-α (TNF-α), rates of bacterial translocation, and expression of intestinal nuclear factor-κB, TNF-α, and intercellular adhesion molecule-1 were determined.

Results

After LT, intestinal mucosa was damaged seriously. At 12, 24, and 48 hours posttransplantation, levels of intestinal sIgA were decreased; levels of malondialdehyde, endotoxin, D-lactic acid, and TNF-α, the ratio of bacterial translocation, and the expression of intestinal nuclear factor-κB, TNF-α, and intercellular adhesion molecule-1 all were increased. However, changes in earlier-mentioned parameters in recipients treated with Gln-EEN were attenuated remarkably at 24 to 48 hours.

Conclusions

Our data show that Gln-EEN is a potent protectant against intestinal mucosal barrier injury after LT.     

Angiopep-2与转铁蛋白共修饰脂质体跨血脑屏障的研究

【摘要】目的：构建angiopep-2与转铁蛋白共修饰脂质体,并对其理化性质和跨血脑屏障能力进行评价。方法 采用薄膜分散法制备转铁蛋白（TF）与angiopep-2共修饰载脂质体（ANG/TF-LPs）,考察其粒径,电位,血清稳定性等理化特征。通过定量细胞摄取实验考察脑内皮bEnd.3细胞对ANG/TF-LPs的摄取效率。构建血脑屏障体外模型,考察不同脂质体的跨血脑屏障能力。结果 所制备的ANG/TF-LPs粒径为93±13.5 nm, Zeta 电位为7.55±1.85 mV。在24 h内具有良好的血清稳定性。体外细胞摄取实验表明,bEnd.3细胞对ANG/TF-LPs的摄取效率分别是TF-LPs、ANG-LPs和LPs的2.9倍、2.4倍和4.8倍,差异具有统计学意义（P<0.01）;ANG/TF-LPs的跨血脑屏障效率分别是TF-LPs、ANG-LPs和LPs的3.1倍、2.9倍和6.8倍,差异具有统计学意义（P<0.01）。结论 ANG/TF-LPs制备工艺简单,经过angiopep-2与转铁蛋白修饰后,脂质体的跨血脑屏障能力显著增强,是一种潜在高效的脑部靶向给药系统。     

脑小血管疾病病理机制的研究进展

在过去十年中全球预期寿命大幅增加,与年龄相关性疾病对社会和卫生保健系统造成的挑战愈演愈烈.脑小血管疾病(cerebral small vessel disease,CSVD)是一种增龄性脑微血管病变,其患病率随年龄增长而增加,在50～90岁人群中患病率由5％升至几乎100％,是导致卒中和血管性痴呆的重要血管因素,并与步...     

应用自评抑郁量表调查血液透析患者的状态及护理

目的了解心理因素对血液透析病人的影响及探寻心理护理对策。方法采用自评抑郁量表(Self-Rating Depression Scale,SDS)调查50例血液透析病人,衡量血液透析患者抑郁状态的轻重程度及其在治疗中的变化。结果 50例血液透析患者中女性21例,发生不同程度的抑郁有16例,男性29例,发生不同程度的抑郁有27例,男女发生抑郁经χ2检验比较,差异无统计学意义(P>0.05);血液透析龄<2年有16人,>3年有34人,SDS得分经t检验比较,差异有统计学意义(P<0.05)。结论血液透析患者普遍存在抑郁的心理问题,不良的情绪将引发免疫力的下降,直接影响透析效果,因此,做好其心理护理至关重要。