Heat shock alters Alzheimer's β amyloid precursor protein expression in human endothelial cells

One of the pathological lesions in Alzheimer's disease (AD) is the amyloid or senile plaque. The plaque core is predominantly made up of amyloid beta peptide (Aβ), a 42–43 amino acid peptide derived from amyloid precursor protein (APP). APP is a membrane bound glycoprotein which is expressed ubiquitously is many cells. Although normal or pathological functions for APP are not well understood, several observations suggest that APP may play a role in cellular stress and inflammation at the endothelial cell/vascular barrier. APP is found in platelets and endothelial cells, it can inhibit a blood coagulation factor, and secreted APP can be neuroprotective. Changes in expression of APP during cellular stress or inflammation may contribute to pathological deposition of Aβ. In the present studies, expression of APP in human endothelial cells was examined following heat shock. In human umbilical vein endothelial cells (HUVECs) exposed to 42°C for 30 min, there was a five-to eight-fold increase in APP mRNA levels which peaked at 4 hr. The increase in APP mRNA was followed by an increase in APP protein immunoreactivity in the cytoplasm in a perinuclear Golgi-like region, and in discrete granular cytoplasmic structures. Immunoblot analysis of APP in the cell media found a transient increase in APP which peaked at 1 hr after heat shock. These results suggest that cellular stress induces the secretion of APP from endothelial cells followed by a subsequent increase in APP mRNA and protein synthesis. The upregulation of APP mRNA and protein supports a cellular stress role for APP. Wiley-Liss, Inc.     

Elucidation of the mechanisms underlying the angiogenic effects of ginsenoside Rg1 in vivo and in vitro

The major active constituents of ginseng are ginsenosides, and Rg₁ is a predominant compound of the total extract. Recent studies have demonstrated that Rg₁ can promote angiogenesis in vivo and in vitro. In this study, we used a DNA microarray technology to elucidate the mechanisms of action of Rg₁. We report that Rg₁ induces the proliferation of HUVECs, monitored using [³H]-thymidine incorporation and Trypan blue exclusion assays. Furthermore, Rg₁ (150–600 nM) also showed an enhanced tube forming inducing effect on the HUVEC. Rg₁ was also demonstrated to promote angiogenesis in an in vivo Matrigel plug assay, and increase endothelial sprouting in the ex vivo rat aorta ring assay. Differential gene expression profile of HUVEC following treatment with Rg₁ revealed the expression of genes related to cell adhesion, migration and cytoskeleton, including RhoA, RhoB, IQGAP1, CALM2, Vav2 and LAMA4. Our results suggest that Rg₁ can promote angiogenesis in multiple models, and this effect is partly due to the modulation of genes that are involved in the cytoskeletal dynamics, cell–cell adhesion and migration. Electronic Supplementary Material An erratum to this article can be found at     

Transplantation of human umbilical vein endothelial cells improves left ventricular function in a rat model of myocardial infarction

Introduction Although cell–based therapy after myocardial infarction (MI) may be beneficial in improving cardiac dysfunction, the underlying mechanisms remain to be clarified. Since human umbilical vein endothelial cells (HUVEC) harbor the potential for transdifferentiation, we studied the functional effects of HUVEC transplantation in a rat model of MI. Methods and results HUVEC labeled with BrdU or medium alone were injected into the infarcted area and its margin 4 weeks after ligation of the left coronary artery in cyclosporine–treated rats. BrdU+ signals could be detected in the area of MI at two weeks and two months after injection only in hearts transplanted with HUVEC. While no signs of transdifferentiation into cardiomyocytes were evident, staining for the rat macrophage marker ED–1, adjacent to or colocalized with BrdU+ signals, revealed an in.ltration with macrophages and implied the phagocytosis of injected HUVEC. In the vicinity of BrdU+ signals, the density of CD31+ microvessels was significantly increased in HUVEC–transplanted as compared to medium–treated hearts after two months. HUVEC transplantation led to improved contractility as assessed by echocardiography and to higher coronary flow rates as well as to improved response to volume strain and catecholamine stress in Langendorff perfused hearts. Conclusions After MI, transplanted HUVEC persist in the host myocardium and trigger an infiltration with macrophages. The ensuing increase in neovascularization and improvement in global left ventricular function may be attributable to the associated inflammatory response.Drs. Merx, Zernecke and Liehn equally contributed to this paper.     

锰对人脐静脉内皮细胞及半胱天冬酶表达影响

目的探讨锰对人脐静脉内皮细胞系HUVEC-304细胞生长周期及半胱天冬酶-3（caspas-3）、半胱天冬酶-8（caspase-8）表达的影响。方法以100～800μmoml／L）的氯化锰分别处理HUVEC-304细胞24～72h后，四甲基偶氮噻唑蓝（MTT）法检测EVC-304细胞的生长活性；流式细胞仪（FCM）检测细胞凋亡情况；蛋白印迹法（Western blot）检捌HUVEC-304细胞在，氯化锰半数抑制浓度（IC50）400μmol／L作用24h时caspase．8、caspase-3的表达。结果氯化锰可呈时间及剂量依赖性抑制HUVEC-304细胞的增殖和诱导细胞凋亡，抑制率为22．34％～90．94％，凋亡率为10．20％～98．73％。氯化锰24hIC50约为400μmol／L，在此浓度下。HUVEC-304细胞caspase-8、caspase-3表达显著增高。（P〈0．05）。结论氯化锰能够抑制HUVEC-304细胞的增殖。星明显的时效和量效关系。caspase-8、cas-pase-3表达增高在细胞增殖和凋亡中起重要的作用，可能是其作用机制之一。     

Serum antibody activity to glomerular endothelial cells is a prospective indicator of renal allograft rejection

Background. Vascular endothelial ells (ECs) are considered to be a primary target for injury in allograft rejection. However, the relationship between serum antibody activity to ECs and rejection episodes has not been extensively examined in renal transplantation. Methods. Twenty-two renal transplant recipients were included in this study. Serum levels of anti-endothelial cell antibody (AECA) were measured using a cellular enzyme-linked immunosorbent assay (ELISA) in which human umbilical vein endothelial cells (HUVEC), human glomerular endothelial cells (HGEC), and human dermal microvascular endothelial cells (MvE) were used as target cells. Serum samples were obtained just before transplantation and once a week during the immediate 1- to 3-month posttransplantation period. Results. There was a significant correlation between the the presence of AECA against HGEC and rejection episodes (P < 0.05). Patients with multiple episodes of rejection showed significantly higher frequencies of AECA than patients with a single episode of rejection (P < 0.001). It should be noted that patients suffering from multiple episodes of rejection had higher AECA titers than those without a rejection episode before transplantation. Conclusions. These findings imply that the HGEC-ELISA could be used as a prospective, informative test to identify patients at a high risk of acute rejection in renal transplantation. Received: December 10, 2001 / Accepted: March 22, 2002     

Low-molecular-weight fucoidan enhances the proangiogenic phenotype of endothelial progenitor cells

Endothelial progenitor cell (EPC) transplantation is a potential means of inducing neovascularization in vivo. However, the number of circulating EPC is relatively small, it may thus be necessary to enhance their proangiogenic properties ex vivo prior to injection in vivo. Fucoidan has previously been shown to potentiate in vitro tube formation by mature endothelial cells in the presence of basic fibroblast growth factor (FGF-2). We therefore examined whether fucoidan, alone or combined with FGF-2, could increase EPC proangiogenic potency in vitro. EPC exposure to 10 microg/ml fucoidan induced a proangiogenic phenotype, including cell proliferation (p < 0.01) and migration (p < 0.01); moreover, differentiation into vascular cords occurred in the presence of FGF-2 (p < 0.01). This latter effect correlated with upregulation of the cell-surface #alpha6 integrin subunit of the laminin receptor (p < 0.05). Compared to untreated HUVEC, untreated EPC #alpha6 expression and adhesion to laminin were enhanced two-fold. Fucoidan treatment further enhanced HUVEC but not EPC adhesion to laminin. These results show that fucoidan enhances the proangiogenic properties of EPC and suggest that ex vivo fucoidan preconditioning of EPC might lead to increased neovascularization when injected into ischemic tissues.     

Bisphosphonates affect migration ability and cell viability of HUVEC,fibroblasts and osteoblasts in vitro

Oral Diseases (2011) 17 , 194–199 Objectives: Bisphosphonate‐associated osteonecrosis of the jaw (BP‐ONJ) is a side effect in patients being treated with bisphosphonates. The bisphosphonates most often associated with BP‐ONJ are the highly potent nitrogen‐containing bisphosphonates, e.g. pamidronate or zoledronate. In terms of BP‐ONJ aetiology, several theories are being discussed: inhibition of bone remodelling, effect on soft tissues, and antiangiogenic effect of bisphosphonates. The aim of this in vitro study was to investigate the effect of different potent bisphosphonates on osteoblasts, fibroblasts and human umbilicord vein endothelial cells (HUVEC). Materials and methods: Three nitrogen‐containing bisphosphonates (ibandronate, pamidronate and zoledronate) and one non‐nitrogen‐containing bisphosphonate (clodronate) were compared concerning their potency on apoptosis induction (tunel), cell viability (calcein assay) and migration potency (boyden chamber) on osteoblasts, fibroblasts and HUVEC. Results: The nitrogen‐containing bisphosphonates, particularly pamidronate and zoledronate, affect cell viability, cell migration and the induction of apoptosis of osteoblasts, fibroblasts and HUVEC. Conclusions: These results support the theory that BP‐ONJ is a multifactorially caused disease because several cell lines of the oral cavity which are responsible for integrity and wound healing are negatively affected by nitrogen‐containing bisphosphonates. Perioperative interruption of bisphosphonate application during dental surgical procedures – if possible – might be feasible to promote better wound healing.     

白花丹参对过氧化氢致人脐静脉血管内皮细胞损伤的保护作用

目的研究白花丹参对过氧化氢（H2O2）所致人脐静脉血管内皮细胞（HUVEC）损失的保护作用。方法应用酶消化灌注法培养人脐静脉血管内皮细胞,采用形态学观察和Ⅷ因子抗体免疫荧光检测法进行鉴定;取对数生长期的细胞分组进行干预,应用形态学观察法和MTT法检测各组血管内皮细胞的活性。结果H2O2损伤模型组细胞损伤明显,经白花丹参高、中、低各剂量组的干预,受损情况均有较明显地改善,使细胞活性（OD值）增高。结论白花丹参对H2O2所致的HUVEC损伤具有保护作用。     

NB-UVB辐射对HUVEC分泌sE-selectin及sICAM-1的影响

目的研究NB-UVB辐射对TNF-α刺激人脐静脉血管内皮细胞(HUVEC)表达可溶性E选择素(sE-se-lectin)及可溶性细胞间黏附分子(sICAM-1)的影响。方法体外培养人脐静脉血管内皮细胞(HU-VEC),将HUVEC接种于96孔塑料培养板,分为对照组,TNF-α组,TNF-α+NB-UVB60mJ/cm2剂量组,TNF-α+NB-UVB40mJ/cm2剂量组,TNF-α+NB-UVB20mJ/cm2剂量组。TNF-α刺激浓度为10ng/mL;NB-UVB高,中,低剂量组剂量分别为20,40,60mJ/cm2。采集上清,ELISA法检测可溶性E选择素(sE-selectin)和可溶性细胞间黏附分子1(sICAM-1)含量。结果 NB-UVB能剂量依赖性地抑制TNF-α刺激后HUVEC分泌sE-selectin和sICAM-1。结论 NB-UVB可能通过抑制血管内皮细胞表达黏附分子在治疗炎症性皮肤病中发挥免疫调节作用。