安体舒通对糖尿病大鼠血管生成素1和血管生成素2表达的影响

目的观察安体舒通对1型糖尿病大鼠肾皮质血管生成素-1(Ang-1)、血管生成素-2(Ang-2)及肾脏血管重建的影响,并初步探讨其机制。方法建立1型糖尿病大鼠模型,用安体舒通干预8周后观察大鼠肾脏血管重建改变,用放射免疫法测定大鼠血浆及肾组织醛固酮水平,用RT-PCR检测各组肾皮质Ang-1和Ang-2mRNA表达。观察安体舒通对上述指标的影响。结果与糖尿病组相比,安体舒通组大鼠肾血管重建改善,血浆及肾组织醛固酮水平更高,Ang-1和Ang-2mRNA表达减少。结论安体舒通通过拮抗醛固酮的作用,减少Ang-1和Ang-2mRNA表达,改善糖尿病肾血管重建从而发挥肾脏保护作用。     

COX-2抑制剂对肺癌裸鼠移植瘤血管生成素基因表达的影响

目的：探讨环氧化酶-2(COX-2)抑制剂尼米舒利（NIM）对肺癌裸鼠移植瘤的血管生成素基因表达的影响及意义。 方法： 人肺癌A549细胞接种于裸鼠皮下，建立肺癌裸鼠移植瘤模型并予NIM治疗，计算NIM的抑瘤率，RT-PCR检测裸鼠移植瘤组织血管生成素-1、2 (Ang-1、Ang-2) mRNA表达, 免疫组织化学法测定裸鼠移植瘤组织微血管密度(MVD)。 结果： NIM可有效抑制裸鼠移植瘤的生长，其抑瘤率为43.02%。 NIM治疗组裸鼠移植瘤组织Ang-2 mRNA水平显著低于对照组（P<0.01），Ang-1 mRNA水平无显著改变（P>0.05）, Ang-2/Ang-1 mRNA比值下降（P<0.01）；同时MVD明显低于对照组（P<0.01）。 结论： COX-2抑制剂NIM可下调Ang-2基因表达,改变Ang-2/Ang-1 mRNA比值，该作用可能是COX-2抑制剂抑制肿瘤血管生成从而抑制肿瘤生长的机制之一。     

Ang-1/Tie2系统与病理性血管形成的关系

血管生成素1(Ang-1)是继血管内皮生长因子(VEGF)之后,人们发现的又一重要的促血管生成因子。血管生成素家族包括Ang-l、Ang-2、Ang-3、Ang-4四种分子。其共同的特异性受体为Tie-2。目前对Ang-1/Tie2系统参与新生血管形成、促进血管成熟、抑制血管渗漏及炎症的作用研究相对深入,在创伤后修复、缺血后再通、肿瘤、糖尿病并发症及子宫内膜异位等多种病理性血管形成过程中起重要作用。     

Ang-1、Ang-2差异表达在大鼠失血性休克血管反应性双相变化中的作用

目的:观察血管生成素-1(Ang-1)、血管生成素-2(Ang-2)在失血性休克后肠系膜上动脉中的表达变化,及其在失血性休克血管反应性双相变化中的作用。方法:采用离体微血管环张力测定技术和Western blotting技术,观察失血性休克后不同时点肠系膜上动脉(SMA)一级分支微血管环的血管反应性、SMA中Ang-1、Ang-2的蛋白表达变化;并观察在缺氧高血管反应期和低血管反应期,给予和抑制Ang-1、Ang-2对SMA一级分支血管环血管反应性的影响。结果:(1)失血性休克后,肠系膜上动脉血管反应性呈早期增高、晚期降低的双相变化,休克10min组NE的Emax最高,为正常的129.3%(P0.01);Ang-1的蛋白表达也呈早期增高、晚期降低的双相变化,休克10min组的Ang-1蛋白表达最高,为正常对照组的1.85倍;Ang-2的蛋白表达在休克早期变化不大,在休克后期逐渐增高,休克4h组的Ang-2蛋白表达最高,为正常对照组的2.90倍。(2)在高血管反应期(缺氧30min),外源性给予Ang-1对血管反应性影响不大,尽管NE的Emax增大,但无显著差异(P0.05),外源性给予Ang-2可降低血管反应性(P0.01);在低血管反应期(缺氧4h),外源性给予Ang-1可改善血管反应性(P0.01),外源性给予Ang-2可进一步降低血管反应性(P0.01)。结论:失血性休克后,肠系膜上动脉存在Ang-1、Ang-2的差异表达,这种差异表达参与了失血性休克血管反应性双相变化的形成。     

药物流产后异常子宫出血者子宫内膜中血管生成素1、2的表达

目的 研究血管生成素1(Ang-1)和血管生成素2(Ang-2)在药物流产后异常子宫出血者子宫内膜组织中的表达,探讨其与异常子宫出血的关系.方法 1087例早孕药物流产后异常出血者的宫腔刮出物行病理学检查;选取40例异常出血者,以20例药物流产后无异常出血者作对照,应用免疫组织化学方法检测两组子宫内膜组织中Ang-1、Ang-2的阳性表达率和表达强度的差异.结果 1.1087例中有绒毛和蜕膜残留者占80.5%;2.Ang-1、Ang-2蛋白在药物流产后的子宫内膜组织的腺上皮及内膜基质细胞和血管壁中均有表达,以在腺体表达为主;3.两组Ang-1、Ang-2表达率均为100%,但异常出血组Ang-1、Ang-2的表达强度均较对照组高,差异有显著性(P<0.01).结论 药物流产后绒毛和蜕膜的残留可能是导致出血时间延长和出血量多的主要原因;药物流产后异常子宫出血者子宫内膜中血管生成素的表达增强,可能引起血管生成的异常,从而使绒毛和蜕膜不容易脱落或子宫内膜的修复受影响,导致了出血时间的延长.     

卵巢上皮肿瘤组织Fas、Angs、E-cad的表达水平及意义分析

目的检测Fas、促血管生成素-1(Ang-1)、促血管生成素-2(Ang-2)、E-钙粘蛋白(E-cad)在卵巢上皮肿瘤组织中的表达水平,藉此评价其与肿瘤发生发展及预后的关系。方法应用免疫组织化学S-P法和原位杂交技术,检查了21例卵巢上皮恶性肿瘤,18例良性肿瘤,8例正常卵巢组织中Fas,Ang-1,Ang-2及E-cad的表达。结果 Fas的表达随肿瘤病变程度的增高而逐步减弱,恶性肿瘤组织与正常卵巢及良性肿瘤组织间有显著差异(P<0．05);E-cad免疫反应阳性强度在卵巢上皮癌组织中明显降低,与正常卵巢及良性肿瘤组织间有显著性差异(P<0．05)。原位杂交显示,Ang-1 mRNA在正常卵巢及肿瘤组织中都有表达,其表达水平没有显著差异(P>0．05);Ang-2 mRNA在恶性肿瘤组织中表达明显上调(P<0．01);E-cad mRNA在恶性肿瘤组织中表达明显下调(P<0.01)。结论 Fas的表达水平与卵巢上皮肿瘤的内在发展相关;由E-cad介导的细胞间黏附作用的减弱是卵巢癌发生、发展及转移的一个重要因素;Ang-2对于促进卵巢癌组织血管新生和形成可能具有重要促进作用。     

喉癌、癌旁组织和正常喉组织中Ang-1、Ang-2、VEGF及其受体表达和临床意义

<正>目的:检测喉癌、癌旁组织和正常喉组织中血管内皮生长因子(VEGF)及其受体(VEGFR)、血管生成素(Ang-1和Ang-2)的表达及其临床意义。方法:用免疫组化SP法检测喉鳞状细胞癌40例、癌旁组织20例及正常喉组织15例的VEGF、VEGFR、Ang-1和Ang-2的表达。结果:VEGF、VEGFR、Ang-1和Ang-2在喉鳞状细胞癌组织中阳性表达分别为72.50%(29/40)、65.00%(26/40)、32.50%(13/40)和67.5%(27/40),在癌旁组织中表达分别为40.00%(8/20)、35.00%(7/20)、30.00%(6/20)和30.00%(6/20),正常喉组织中VEGF、VEGFR、Ang-1和Ang-2表达为20.00%(3/15)、13.33%(2/15)、33.33%(5/15)和20.00%(3/15)。     

血管生成素的作用机制和功能

血管生成素(angiopoietin,Ang)是1组分泌型的细胞因子,该细胞因子家族在血管重塑、胚胎血管发育、癌症等研究热点中起着重要作用。我们根据目前研究现状,对血管生成素家族做一简要介绍。 一、引言 血管生成素家族的4位成员:Ang-1、Ang-2、Ang-3和Ang-4所起的作用相互之间迥然不同,而其受体Tie-1、Tie-2     

Akt-eNOS-NO信号途径介导了Ang-1和Ang-2对大鼠失血性休克早期血管高反应性的调节作用

目的:观察内皮型一氧化氮合酶(endothelial nitric oxide synthase, eNOS)在血管生成素1(angiopoietin-1, Ang-1)和血管生成素2(angiopoietin-2, Ang-2)调节失血性休克大鼠血管反应性双相变化中的作用及其机制。方法:采用Western blotting技术观察失血性休克后不同时点肠系膜上动脉(superior mesenteric artery,SMA)中eNOS蛋白表达变化,采用离体微血管环张力测定技术观察eNOS抑制剂对Ang-1和Ang-2调节缺氧早期和晚期血管反应性作用的影响,并观察给予Ang-1、Ang-2以及Tie-2、Akt、p38 MAPK、ERK抑制剂后缺氧血管内皮细胞(vascular endothelial cells, VECs)和血管平滑肌细胞(vascular smooth muscle cells, VSMCs)混合培养物中eNOS蛋白表达和培养上清一氧化氮(nitric oxide, NO)含量的影响。结果:(1)eNOS在正常SMA中表达很低,失血性休克后逐渐增高,休克10min、30min、1h、2h和4 h时分别增高至正常对照的1.95、2.10、3.01、3.42和3.57倍(P<0.01)。(2)eNOS抑制剂可显著抑制缺氧10min的血管高反应性,去甲肾上腺素(NE)的E_max由13.479 mN降低至9.043 mN(P<0.01),也可以显著抑制Ang-1对缺氧10min血管高反应性的维持作用,NE的E_max由15.283 mN降低至11.219 mN(P<0.01),但不改变Ang-2降低缺氧10 min血管高反应性作用,也不改变缺氧4h的血管低反应性和Ang-1、 Ang-2对缺氧4 h血管反应性的调节作用。(3)缺氧10 min的eNOS表达较正常对照增高,Ang-2和Tie-2、Akt抑制剂可抑制其增高(P<0.01),p38 MAPK、ERK抑制剂对其无显著影响。(4)NO含量在缺氧10 min显著增高,Ang-2和Tie-2、Akt、eNOS抑制剂可抑制其增高(P<0.01),p38 MAPK、ERK抑制剂对其无显著影响。结论:失血性休克早期,Ang-1和Ang-2通过Akt-eNOS-NO途径来调节血管高反应性。     

血管生成因子在糖尿病大鼠心肌组织的表达

 目的：检测糖尿病大鼠心肌组织中血管生成因子的表达。方法：选择雄性SD大鼠一次性腹腔注射链脲佐菌素制造1型糖尿病模型,糖尿病成功诱导后12周,运用MPA心功能分析系统评估心功能改变,Masson染色计算心肌胶原容积分数（collagen volume fraction,CVF）,CD31免疫组织化学法测定心肌毛细血管并计算心肌毛细血管/心肌细胞比值（capillary/myocyte,C/M）,Western blotting检测血管内皮生成因子（VEGF）、血管生成素1（angiopoietin-1,Ang-1）、血管生成素2（angiopoietin-2,Ang-2）和内皮抑素(endostatin) 在心肌组织中的表达。结果：与正常对照组比较,糖尿病大鼠左心室舒张末期压力(LVEDP)明显增高(P<001),而左心室压力上升最大速率(+dp／dtmax)和左心室压力下降最大速率(-dp／dtmax)均明显下降（P<0.05）;心肌C/M比值、 VEGF和Ang-1表达明显减少（P<0.05）;而心肌CVF含量和endostatin表达显著增高（P<0.05）,但Ang-2表达无明显差异。结论：VEGF和Ang-1在糖尿病大鼠心肌组织表达下调,endostatin表达显著上调,可能是糖尿病心肌病发生的重要机制。     

血管形成因子家族的结构和功能的研究进展

血管是机体的重要组成部分。机体内营养物质和氧通过血管运输到全身各个细胞 ,维持机体正常的代谢和功能。业已证实血管的形成以及其后稳态的保持 ,受许多细胞因子调控 ,其中血管形成因子(ａｎｇｉｏｐｏｉｅｔｉｎ ,Ａｎｇ)家族起着十分重要的作用[1,2 ] 。自 1996年Ｄａｖｉｓ等[3] 首次克隆出Ａｎｇ - 1基因以来 ,不断有新的血管形成因子及其类似蛋白被发现[4 - 6 ] ,并且有关该家族成员对血管结构和功能的影响的研究正日益增多。1　血管形成因子的ｃＤＮＡ克隆和分布具有免疫球蛋白和表皮细胞因子相同结构域的酪氨酸蛋白激酶 - 2 (ｔｙ…     

Altered expression of angiopoietins during blood-brain barrier breakdown and angiogenesis

Angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) belong to a novel family of endothelial growth factors that function as ligands for the endothelial-specific receptor tyrosine kinase, Tie-2. Ang-1 reduces endothelial permeability of noncerebral vessels and has a major role in vascular stabilization and maturation, whereas Ang-2 is thought to be an endogenous antagonist of the action of Ang-1 at Tie-2. Expression of these ligands at the mRNA and protein level were studied during both blood-brain barrier (BBB) breakdown and cerebral angiogenesis occurring in the rat cortical cold-injury model by RT-PCR analysis and immunohistochemistry respectively, during a time course of 6 hours to 6 days. In addition, immunohistochemical detection of fibronectin was used to detect BBB breakdown at the lesion site and dual labeling was used to determine whether the vessels demonstrating BBB breakdown expressed endothelial Ang-1 or Ang-2. Endothelial Ang-1 and Tie-2 proteins were present in all cerebral vessels of normal brain including those of the choroid plexuses, whereas both these proteins as well as Ang-2 were present in choroid plexus epithelium and in ependymal cells, suggesting that angiopoietins have an autocrine effect on these cell types as well. In contrast, in the early phase after injury during the known period of BBB breakdown, increased Ang-2 mRNA and protein and decreased endothelial Ang-1 and Tie-2 proteins were observed. Two to 6 days after injury, the progressive increase in Ang-1 mRNA and protein and the decrease in Ang-2 coincided with cerebrovascular angiogenesis. Confocal microscopy showed colocalization of both Ang-1 and Ang-2 in endothelium of lesion vessels, and our observation of colocalization of Ang-1 and Ang-2 in polymorphonuclear leukocytes and macrophages has not been reported previously. This study demonstrates that Ang-1 is an important factor in maintaining normal homeostasis in the brain. Thus Ang-1 therapy may have therapeutic potential in reducing BBB breakdown and the ensuing edema after massive brain injury.     

Expression of angiopoietin-1 in osteoblasts and its inhibition by tumor necrosis factor-alpha and interferon-gamma

Angiogenesis is a crucial component of bone remodeling under both normal and pathophysiological conditions. Among the various mediators that regulate the angiogenic process is the angiopoietin (Ang) family of growth factors. Ang-1 stabilizes new blood vessels by recruiting surrounding mesenchymal cells and promoting their differentiation into vascular smooth muscle cells, whereas Ang-2 is a natural antagonist of Ang-1 and can inhibit angiogenesis. The expression of Ang-1 and Ang-2 in human osteoblasts (hOBs) isolated from rheumatoid arthritis (RA) and osteoarthritis (OA) patients and from healthy individuals has been examined. After incubation in the presence or absence of tumor necrosis factor-alpha (TNF-alpha) and/or interferon-gamma (IFN-gamma), the culture supernatants were assayed for Ang using an enzyme-linked immunosorbent assay. In addition, expression of Ang protein and mRNA was examined using immunohistochemical techniques and quantitative real-time polymerase chain reaction, respectively. It was found that hOBs expressed Ang-1 but not Ang-2 protein, and cultured hOBs from RA and OA patients and from healthy individuals all spontaneously secreted significant amounts of Ang-1 in the absence of any stimulation. Although stimulation with TNF-alpha or IFN-gamma had little or no effect on Ang-1 secretion, costimulation with IFN-gamma plus TNF-alpha dose- and time-dependently diminished secretion of Ang-1 from hOBs. This inhibitory effect was mediated in part by nuclear factor-kappa B via upregulated expression of inducible nitric oxide synthase and enhanced synthesis of nitric oxide. Taken together, these findings suggest that OBs are an important cellular source of Ang-1 and may modulate bone remodeling through regulation of angiogenesis.     

Expression of the angiopoietins and their receptor Tie2 in human renal clear cell carcinomas; regulation by the von Hippel-Lindau gene and hypoxia

Angiogenesis is essential for tumour growth and metastasis, and is co-ordinated by several classes of angiogenic factors. To determine the significance and regulation of the angiopoietin (Ang) pathway in highly vascular human renal cell carcinomas (RCCs), this study has investigated the expression of the Ang-1, Ang-2, Ang-4, and Tie2 genes in a series of normal (n = 26) and neoplastic (n = 45; clear cell n = 35, papillary n = 10) human kidney tissues, examined the pattern of Ang-2 and Tie2 protein expression, and correlated expression with clinicopathological variables. The effect of the von Hippel-Lindau (VHL) gene and hypoxia in the renal cell lines RCC786-0 and RCC4 has also been investigated. Ang-1, Ang-2 and Tie2, but not Ang-4 mRNA, were detected in normal and tumour samples. A significant increase in Ang-2 (p < 0.001) and a decrease in Tie2 receptor mRNA (p = 0.001) were observed, but no significant difference was observed in Ang-1 mRNA abundance between normal kidney and RCC (p = 0.37). Immunohistochemistry for Ang-2 showed strong expression in vascular endothelium and weak expression in tumour cells, whereas Tie2 was expressed exclusively on endothelium. Tie2 gene expression was positively correlated with Ang-2 expression in cancers (p = 0.001) and showed a borderline significant association with Ang-1 (p = 0.06), but there was no significant relationship between Ang-1 and Ang-2 (p = 0.69). No significant relationships were observed in clear cell carcinomas between Ang-1, Ang-2 and Tie2 mRNA abundance and patient sex, patient age, or tumour size (p > 0.05). However, there was significantly greater Ang-1 (p = 0.02), Ang-2 (p = 0.03), and Tie2 (p = 0.04) mRNA abundance in clear cell than in chromophil RCCs. Ang-2 gene expression was down-regulated by hypoxia in VHL wild-type RCC786-0 and RCC4 transfectants (p = 0.0002 and p = 0.04, respectively), mirroring the low expression in human tumour cells. These data suggest that it is endothelial induction of Ang-2 in tumours that regulates vessel stability and supports targeting Tie2 as an effective novel anti-angiogenic therapy in clear cell RCCs.     

Angiogenetic axis angiopoietins/Tie2 and VEGF in familial breast cancer

Angiogenesis leads to the formation of blood vessels from pre-existing ones, allowing tumor growth. Vascular endothelial growth factor (VEGF) and Angiopoietins (Ang-1, Ang-2) have a pivotal role in tumor angiogenesis but few data regarding their role in hereditary breast cancer are available. The aim of the present study was to analyze Ang-1, Ang-2, tyrosine-protein kinase receptor Tie2 and VEGF expression and their correlation in a cohort of familial and sporadic breast cancers in order to verify whether the presence of germline mutations in BRCA may have a role in tumor microenvironment regulation. Tumor samples from a cohort of 41 patients with a first diagnosis and a family history of breast cancer and 19 patients with sporadic breast cancers were enrolled. The expression of Tie2, Ang-1, Ang-2 and VEGF were analyzed by quantitative real-time PCR. Patients harboring BRCA mutations had higher levels of Ang-1 (P=0.05), Ang-2 (P=0.02) and VEGF (P=0.04) mRNA compared with those without BRCA mutations (BRCAX). The same was observed in triple-negative breast cancer (TNBC). Moreover, a positive correlation between Ang-2 and VEGF was found in both the familial breast cancer group (BRCA carriers: r=0.83; P<0.0001 and BRCAX: r=0.58; P=0.008) and in TNBC (r=0.62; P=0.007). The higher levels of Ang-1, Ang-2 and VEGF mRNA found in BRCA carriers and TNBCs suggest that they could be attractive angiogenic therapeutic targets in these breast cancers.     

Expression of angiopoietin-1, angiopoietin-2, and tie receptors after middle cerebral artery occlusion in the rat

Vascular endothelial growth factor (VEGF), a key regulator of vasculogenesis and embryonic angiogenesis, was recently found to be up-regulated in an animal model of stroke. Unlike VEGF, angiopoietin (Ang)-1 and -2, their receptor tie-2, and the associated receptor tie-1 exert their functions at later stages of vascular development, i.e., during vascular remodeling and maturation. To assess the role of the angiopoietin/tie family in ischemia-triggered angiogenesis we analyzed their temporal and spatial expression pattern after middle cerebral artery occlusion (MCAO) using in situ hybridization and immunohistochemistry. Ang-1 mRNA was constitutively expressed in a subset of glial and neuronal cells with no apparent change in expression after MCAO. Ang-2 mRNA was up-regulated 6 hours after MCAO and was mainly observed in endothelial cell (EC) cord tips in the peri-infarct and infarct area. Up-regulation of both Ang-2 and VEGF coincided with EC proliferation. Interestingly, EC proliferation was preceded by a transient period of EC apoptosis, correlating with a change in VEGF/Ang-2 balance. Our observation of specific stages of vascular regression and growth after MCAO are in agreement with recent findings suggesting a dual role of Ang-2 in blood vessel formation, depending on the availability of VEGF.     

Deregulation of levels of angiopoietin-1 and angiopoietin-2 is associated with severe courses of hantavirus infection

BackgroundHantavirus disease is characterized by endothelial dysfunction. Angiopoietin-1 (Ang-1) and its antagonist angiopoietin-2 (Ang-2) play a key role in the control of capillary permeability. Ang-1 is responsible for maintenance of cell-to-cell contacts whereas Ang-2 destabilizes monolayers. An imbalance of Ang-1 and Ang-2 levels results in enhanced permeability and capillary leakage.ObjectivesTo analyze the involvement of angiopoietins in hantavirus-induced disruption of endothelia, we measured the levels of Ang-1 and Ang-2 in hantavirus infection.Study designLevels of angiopoietins of 31 patients with acute Puumala virus (PUUV) infection and a patient infected with Dobrava-Belgrade virus genotype Sochi (DOBV-Sochi) were analyzed. An age-matched group of 16 healthy volunteers served as control. The ratios of Ang-2 to Ang-1 levels were calculated and correlated with laboratory parameters.ResultsPatients with PUUV and DOBV-Sochi infection exhibited elevated ratios of Ang-2/Ang-1 compared to the control group. The imbalance of Ang-2 to Ang-1 levels was observed early after onset of symptoms and lasted for the acute phase of infection. The deregulation in DOBV-Sochi infection was more prominent than in PUUV infection. Analysis of Ang-2/Ang-1 ratio and laboratory parameters in the PUUV cohort revealed a positive correlation with serum creatinine and a negative correlation with serum albumin and thrombocyte levels.ConclusionsWe observed an imbalance between levels of Ang-1 and Ang-2 in patients infected with PUUV and DOBV-Sochi. Elevated Ang-2/Ang-1 ratios correlate with disease severity. The virus-induced deregulation of angiopoietin levels may enhance capillary permeability and contribute to the pathogenesis of hantavirus disease.     

Association of Ang-2 with Integrin β2 Controls Ang-2/PDGF-BB-Dependent Upregulation of Human Peripheral Blood Monocyte Fibrinolysis

Angiopoietin-2 (Ang-2), an angiogenic factor that is generally considered an autocrine factor for endothelial cells was shown in a previous study to upregulate peripheral blood monocyte fibrinolysis in concert with platelet-derived growth factor-BB (PDGF-BB). This upregulation of fibrinolysis was demonstrated to be due to upregulation of elements of the matrix metalloproteinase and serine protease fibrinolytic pathways. The manner in which Ang-2 interacts with monocytes was not elucidated though no expression of the angiopoietin receptor tyrosine kinase Tie-2 was found for monocytes. In this study Ang-2 was found to bind to integrin β₂, and functional inhibition of integrin β₂ eliminated Ang-2/PDGF-BB-mediated upregulation of monocyte fibrin invasion. Additionally, integrin β₂ blockade significantly inhibited the Ang-2/PDGF-BB based increase in matrix metalloproteinase-9 (MMP-9) and membrane type-1-MMP (MT1-MMP). Furthermore, Ang-2/PDGF-BB-upregulated urokinase plasminogen-activator receptor (uPAR) was shown to be associated in complexes with integrin β₂. In addition, Ang-2 was shown to upregulate PDGFR-β expression in monocytes. Therefore several components of the mechanism via which the novel interaction of Ang-2 and PDGF-BB with monocytes occurs have been identified.