Toxicological study of metal and metal oxide nanoparticles in zebrafish

Metal and metal oxide nanoparticles have been widely used in catalytic, electronic and biomedical fields. It is necessary to investigate their toxicity and potential hazards to human and aquatic ecosystems. Zebrafish (Danio rerio), as a promising animal model, has been increasingly utilized to assess the toxicity of nanoparticles. Zebrafish has numerous characteristics for toxicity evaluation, such as short life cycle and high fecundity. This review describes the advantages of using zebrafish in the toxicity assessment of metal and metal oxide nanoparticles. Then we focus on the toxic effects, particularly the acute toxicity and the chronic ones, induced by nanoparticles in zebrafish. Target organ toxicities are also mentioned, including immunotoxicity, developmental toxicity, neurotoxicity, reproductive toxicity, cardiovascular toxicity and hepatotoxicity. The toxic effects of selected metal nanoparticles, including Au, Ag, Cu, and metal oxide nanoparticles such as TiO₂, Al₂O₃, CuO, NiO and ZnO, as well as the underlying mechanisms of nanoparticles causing these effects, are also highlighted and described in detail. Furthermore, we introduce the general factors that affect nanoparticle-induced toxicity in zebrafish. The drawbacks and advantages of using the zebrafish model in nanotoxicity studies are also argued. Finally, we suggest that the application of zebrafish to assess chronic toxicity of metal and metal oxide nanoparticles and the joint toxicity of metal and metal oxide nanoparticles and other pollutants could be hot topics in nanotoxicology.     

Exosomes from miRNA‐126‐modified endothelial progenitor cells alleviate brain injury and promote functional recovery after stroke

AimsWe previously showed that the protective effects of endothelial progenitor cells (EPCs)‐released exosomes (EPC‐EXs) on endothelium in diabetes. However, whether EPC‐EXs are protective in diabetic ischemic stroke is unknown. Here, we investigated the effects of EPC‐EXs on diabetic stroke mice and tested whether miR‐126 enriched EPC‐EXs (EPC‐EXs^miR126) have enhanced efficacy.MethodsThe db/db mice subjected to ischemic stroke were intravenously administrated with EPC‐EXs 2 hours after ischemic stroke. The infarct volume, cerebral microvascular density (MVD), cerebral blood flow (CBF), neurological function, angiogenesis and neurogenesis, and levels of cleaved caspase‐3, miR‐126, and VEGFR2 were measured on day 2 and 14.ResultsWe found that (a) injected EPC‐EXs merged with brain endothelial cells, neurons, astrocytes, and microglia in the peri‐infarct area; (b) EPC‐EXs^miR126 were more effective than EPC‐EXs in decreasing infarct size and increasing CBF and MVD, and in promoting angiogenesis and neurogenesis as well as neurological functional recovery; (c) These effects were accompanied with downregulated cleaved caspase‐3 on day 2 and vascular endothelial growth factor receptor 2 (VEGFR2) upregulation till day 14.ConclusionOur results indicate that enrichment of miR126 enhanced the therapeutic efficacy of EPC‐EXs on diabetic ischemic stroke by attenuating acute injury and promoting neurological function recovery.     

Nitric oxide donors offer protection to RBC from storage lesion

BackgroundRed blood cell (RBC), which is the most commonly transfused blood component, due to its ability to save a life in absence of any other blood components, can be stored up to maximum 6 weeks by following standard preservation procedure. During storage, RBC undergoes various biophysical and biochemical changes (commonly known as storage lesion) for which blood transfusion with “old RBC” shows a lot of clinical problems especially relevant to critically ill patients. Recent research on S-nitrosylation of haemoglobin to improve oxygen delivery of banked blood revealed the important role of nitric oxide (NO) in protecting storage lesion.Materials and methodsIn the present study, we used various “NO donating” chemicals with different NO release dynamics and chemistries in RBC storage cocktails to test the effects of NO on storage lesion. Changes in different storage markers were evaluated after 7 days storage of pre-treated RBC.ResultsAll the NO donors have shown protection against hemolysis. However, S-nitroso glutathione (GSNO) ranks first in shielding RBCs from storage lesion and additionally, it helps in elevating the value of 2, 3-di phosphoglycerate (2, 3-DPG), improving the RBC membrane fluidity and decreasing the adhesion towards endothelial monolayer.DiscussionPresent study reveals that NO released from NO donors confers protection against storage lesions of the RBC. Further, the study confirms that pre-treatment with GSNO, a NO donor and a nitrosylating agent, ensures the best protection to RBC during low temperature storage, when compared to other NO donor treatments.     

Poly-ICLC,a multi-functional immune modulator for treating cancer

Immunotherapies have become the first line of treatment for many cancer types. Unfortunately, only a small fraction of patients benefits from these therapies. This low rate of success can be attributed to 3 main barriers: 1) low frequency of anti-tumor specific T cells; 2) lack of infiltration of the anti-tumor specific T cells into the tumor parenchyma and 3) accumulation of highly suppressive cells in the tumor mass that inhibit the effector function of the anti-tumor specific T cells. Thus, the identification of immunomodulators that can increase the frequency and/or the infiltration of antitumor specific T cells while reducing the suppressive capacity of the tumor microenvironment is necessary to ensure the effectiveness of T cell immunotherapies.In this review, we discuss the potential of poly-ICLC as a multi-functional immune modulator for treating cancer and its impact on the 3 above mentioned barriers. We describe the unique capacity of poly-ICLC in stimulating 2 separate pattern recognition receptors, TLR3 and cytosolic MDA5 and the consequences of these activations on cytokines and chemokines production. We emphasize the role of poly-ICLC as an adjuvant in the setting of peptide-based cancer vaccines and in situ tumor vaccination by mimicking natural immune responses to infections. Finally, we summarize the impact of poly-ICLC in enhancing T infiltration into the tumor parenchyma and address the implication of this finding in the clinic.     

Systemic capillary leak syndrome triggered by anti-programmed death 1 checkpoint inhibitor in psoriasis

Programmed death 1 (PD-1) inhibitors are increasingly used for the treatment of malignancies. Despite the clinical benefits, unpredictable and potentially fatal side-effects may occur. We report a psoriatic patient who developed systemic capillary leak syndrome (SCLS) after starting a PD-1 checkpoint inhibitor. In order to determine which factors could trigger the development of SCLS in a patient with stable psoriasis after starting anti-PD-1 therapy, serum cytokines were serially measured before and after the development of SCLS in this patient. We also retrospectively reviewed 28 previously reported patients presenting clinical exacerbations of pre-existing psoriasis or the de novo induction of psoriasis after anti-PD-1 therapy. In 16 of the 28 patients (57.1%), the interval between last anti-PD-1 therapy and exacerbations of pre-existing psoriasis or the de novo induction of psoriasis was less than 28 days. The timing of the onset of SCLS in this patient was coincident with the increase in lymphocyte counts and at 22 days after last anti-PD-1 therapy. In 75%, however, anti-PD-1 therapy was able to be restarted and was tolerated well. Increased levels of interleukin (IL)-2, IL-6, interferon-γ and tumor necrosis factor-α, in addition to a persistent increase in vascular endothelial growth factor (VEGF), were detected at onset of SCLS. An increase in pro-inflammatory cytokines and VEGF, when combined with a rapid and sequential recovery of neutrophils and lymphocytes after anti-PD-1 therapy, would predict the development of SCLS. Clinicians need to be aware that patients with psoriasis are at risk of a potentially fatal disease, SCLS, when anti-PD-1 therapy is started.     

血管内皮生长因子基因修饰诱导多能干细胞的生物学特性的研究

目的 探讨血管内皮生长因子(vascular endothelial growth factor,VEGF)基因修饰诱导多能干细胞(induced pluripotent stem cells,iPS)的生物学特性。方法 将培养好的iPS细胞分为3组,即N0(纯iPS培养)组、N1(空腺病毒载体转染iPS)组、N2(转染VEGF基因的iPS)组; 3组细胞分别进行传代培养,并采用MTT方法检测转染VEGF基因对细胞增殖的影响; 采用酶联免疫(ELISA)方法检测细胞培养上清液中VEGF的表达水平。结果 转染VEGF基因对iPS细胞增殖没有明显影响; N2组iPS细胞分泌的VEGF蛋白表达水平较N1组显著增加(P<0.05)。结论 经VEGF基因转染的iPS可正常存活生长,并可稳定表达该基因。     

枸杞多糖对颅内动脉瘤大鼠NF-κB信号通路及血管内皮组织炎性损伤的影响

目的 探讨枸杞多糖(LBP)对颅内动脉瘤(IA)大鼠核蛋白因子-κB(NF-κB)蛋白通路及血管内皮组织炎性损伤的影响。方法 取SD雌性大鼠50只,采用切除双侧卵巢并结扎左侧颈总动脉及双侧肾动脉后支以构建IA模型,随机分为IA模型组、LBP低(5 mg/kg)、中(10 mg/kg)、高(20 mg/kg)剂量组,另取10只大鼠,只暴露卵巢、颈总动脉、双侧肾动脉后支,不进行摘除和结扎,作为对照组(Control组); 各组均于手术1周后,开始给药,Control组、IA模型组经灌胃给予生理盐水,LBP各剂量组灌胃给予相应剂量药物,1次/d,共给药30 d; 末次给药12 h后处死,取大鼠血液用酶联免疫吸附法(ELISA)检测血清炎性因子白细胞介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)及血管内皮损伤标志物血管内皮生长因子(VEGF)、血管内皮素(ET)水平; 分离取出大鼠脑动脉(Wills)环,在40倍显微镜下检查大脑动脉(Wills)环病理改变,并检测动脉瘤血管壁厚度及动脉瘤体积; 取脑动脉瘤血管组织,用苏木精-伊红染色(HE)检测动脉瘤血管组织病理变化; 蛋白免疫印迹法(Western blot)检测动脉瘤血管组织NF-κB,Toll样受体-4(TLR4)蛋白表达水平。结果 与Control组比较,IA模型组大鼠Willis环上凸起、管壁厚度和肿动脉瘤体积、动脉瘤内皮细胞空泡变性及炎性细胞浸润等病理损伤程度、血清IL-6,TNF-α,VEGF,ET水平、动脉瘤血管组织NF-κB和TLR4蛋白表达水平明显升高(P<0.05); 与IA模型组比较,LBP低、中、高剂量组大鼠Willis环上凸起、管壁厚度和动脉瘤体积、动脉瘤内皮细胞空泡变性及炎性细胞浸润等病理损伤程度、血清IL-6,TNF-α,VEGF,ET水平、动脉瘤血管组织NF-κB和TLR4蛋白表达水平明显降低(P<0.05),且LBP各剂量组上述指标水平呈剂量依赖性降低。结论 LBP可能通过抑制TLR4/NF-κB通路激活、降低炎症反应来减轻IA血管内皮组织损伤。