Vascular endothelial growth factor in nasal polyps: a comparison of asthmatic and non‐asthmatic patients

The cause of nasal polyps remains unknown, although there is a well‐recognized clinical association between nasal polyposis and asthma. The characteristic histological features of nasal polyps include large quantities of extracellular fluid. Vascular endothelial growth factor (VEGF) is a potent mediator of angiogenesis and vascular permeability. This study aimed to compare expression of VEGF in nasal polyps from patients with asthma and those with no apparent respiratory disease. Twenty‐four asthmatic and 35 non‐asthmatic patients were studied using immunohistochemistry for VEGF. VEGF expression was identified in endothelial, inflammatory and epithelial cells. There was significantly greater endothelial expression of VEGF in asthmatic patients (P < 0.05). Greater epithelial expression was observed in asthmatic patients but this did not reach statistical significance (P = 0.07). There was no difference in the density of inflammatory cells expressing VEGF. Differences between the two groups may reflect differences in disease severity or in the nature of the inflammatory process.     

Immunohistochemical demonstration and semi-quantitation of vascular endothelial growth factor in recurrent versus non-recurrent nasal polyps

Objective The expression of some growth factors in nasal polyps has been examined, although investigations addressing the reason for recurrence in some patients are lacking. Vascular endothelial growth factor (VEGF) is expressed by inflammatory cells, as well as by endothelial and epithelial cells of nasal polyps. To determine whether VEGF may play a role in the recurrence of nasal polyps, we aimed to compare VEGF expression in recurrent versus non-recurrent polyps. In addition, expression in polyps from asthmatic patients was compared with that in polyps from non-asthmatics.

Material and Methods A total of 30 patients with newly diagnosed nasal polyposis were included. Polypectomy was performed at enrolment in the long-term follow-up study. Fifteen patients had only 1 polypectomy (non-recurrence group; median observation period 81 months) and 15 had a median of 6.4 polypectomies (multiple recurrence group; median observation period 108 months). Five of 10 patients with asthma belonged to the non-recurrence group and 5 to the recurrence group. The polyp obtained at the initial polypectomy was examined for expression of VEGF by immunohistochemistry, using a polyclonal antibody. A blinded semi-quantitation and comparison of the intensity of immunolabelling were performed in recurrent versus non-recurrent polyps, as well as in asthmatics versus non-asthmatics.

Results VEGF expression was seen as varying staining of the polyp surface and gland epithelium, as well as of the vessel endothelium and some stromal mono- and polymorphonuclear leukocytes. Semi-quantitation of the staining intensity showed no significant differences between recurrent and non-recurrent polyps, or between asthmatics and non-asthmatics.

Conclusion Our findings indicate that the level of immunohistochemical expression of VEGF in recurrent and non-recurrent nasal polyposis is equivalent. Thus, the level of VEGF expression cannot predict a subsequent recurrence. The expression of VEGF is not upregulated in patients with asthma. Further studies are needed to determine the role of VEGF in nasal polyposis, with special reference to different stages of polyp formation, vascularization and growth.     

Immunohistochemical demonstration and semi-quantitation of vascular endothelial growth factor in recurrent versus non-recurrent nasal polyps

OBJECTIVE: The expression of some growth factors in nasal polyps has been examined, although investigations addressing the reason for recurrence in some patients are lacking. Vascular endothelial growth factor (VEGF) is expressed by inflammatory cells, as well as by endothelial and epithelial cells of nasal polyps. To determine whether VEGF may play a role in the recurrence of nasal polyps, we aimed to compare VEGF expression in recurrent versus non-recurrent polyps. In addition, expression in polyps from asthmatic patients was compared with that in polyps from non-asthmatics. MATERIAL AND METHODS: A total of 30 patients with newly diagnosed nasal polyposis were included. Polypectomy was performed at enrolment in the long-term follow-up study. Fifteen patients had only 1 polypectomy (non-recurrence group; median observation period 81 months) and 15 had a median of 6.4 polypectomies (multiple recurrence group; median observation period 108 months). Five of 10 patients with asthma belonged to the non-recurrence group and 5 to the recurrence group. The polyp obtained at the initial polypectomy was examined for expression of VEGF by immunohistochemistry, using a polyclonal antibody. A blinded semi-quantitation and comparison of the intensity of immunolabelling were performed in recurrent versus non-recurrent polyps, as well as in asthmatics versus non-asthmatics. RESULTS: VEGF expression was seen as varying staining of the polyp surface and gland epithelium, as well as of the vessel endothelium and some stromal mono- and polymorphonuclear leukocytes. Semi-quantitation of the staining intensity showed no significant differences between recurrent and non-recurrent polyps, or between asthmatics and non-asthmatics. CONCLUSION: Our findings indicate that the level of immunohistochemical expression of VEGF in recurrent and nonrecurrent nasal polyposis is equivalent. Thus, the level of VEGF expression cannot predict a subsequent recurrence. The expression of VEGF is not upregulated in patients with asthma. Further studies are needed to determine the role of VEGF in nasal polyposis, with special reference to different stages of polyp formation, vascularization and growth.     

血管内皮生长因子在鼻息肉组织中的表达和意义

目的探讨血管内皮生长因子(vascular endothelial growth factor, VEGF)在鼻息肉组织中的表达及其在鼻息肉发病中的意义。方法将鼻息肉患者分为A、B 组,A组为Ⅱ型1、2期患者,B组为Ⅱ型3期及Ⅲ型患者。另有20例鼻中隔偏曲患者的正常下鼻甲组织作对照组。采用免疫组化SP法检测三组VEGF的表达。结果正常鼻黏膜中VEGF的染色呈弱阳性,而在A、B组鼻息肉组织中VEGF的阳性率明显高于对照组,B组中阳性率和阳性细胞数均高于A组;VEGF在鼻息肉组织中主要定位于基底膜周围的炎性细胞和上皮细胞以及腺体、血管周围和血管壁内皮细胞。结论VEGF通过在鼻息肉组织中过度表达促进息肉组织内的血管增殖和炎性细胞聚积,促进鼻息肉的发生发展。     

Expression, localization, and significance of vascular permeability/vascular endothelial growth factor in nasal polyps

BACKGROUND: The exact etiologic mechanisms leading to the formation of nasal polyps have remained largely obscure. A key phenomenon of this specific type of chronic inflammatory disease in nasal respiratory mucosa is remarkable edema. Vascular permeability/vascular endothelial growth factor (VPF/VEGF) plays an important role in inducing angiogenesis and modulating capillary permeability. OBJECTIVE: To study the expression and localization of VPF/ VEGF as a putative key factor in nasal polyp development. METHODS: Specimens of nasal polyps (n = 12) were harvested during endonasal sinus surgery in patients with polypous chronic rhinosinusitis. Specimens of healthy nasal respiratory mucosa (n = 12) served as controls and were obtained from inferior turbinates of patients undergoing surgery for nasal obstruction without signs and symptoms of inflammatory disease. Frozen sections were immunohistochemically stained for VPF/VEGF and quantitatively analyzed, using computer-based image analysis. RESULTS: The expression of VPF/VEGF in specimens of nasal polyps was significantly stronger than in specimens of healthy nasal mucosa of controls. VPF/VEGF in polypous tissue was mainly localized in vascular endothelial cells, in basal membranes and perivascular spaces, and in epithelial cells. CONCLUSION: The markedly increased expression in nasal polyps as opposed to healthy nasal mucosa suggests that VPF/VEGF may play a significant role in both the formation of nasal polyps and in the induction of heavy tissue edema. This finding is discussed with respect to the differential expression of cyclooxygenase (COX) isoenzymes-1 and -2 (COX-1 and COX-2) in nasal polyps was significantly stronger than in specimens of healthy nasal mucosa of controls. VPF/VEGF in polypous tissue was mainly localized in vascular endothelial cells, in basal membranes and perivascular spaces, and in epithelial cells. Conclusion: The markedly increased expression in nasal polyps as opposed to healthy nasal mucosa suggests that VPF/VEGF may play a significant role in both the formation of nasal polyps and in the induction of heavy tissue edema. This finding is discussed with respect to the differential expression of cyclooxygenase (COX) isoenzymes-1 and -2 (COX-1 and COX-2) in nasal polyps.     

Activated eosinophils in nasal polyps: a comparison of asthmatic and non‐asthmatic patients

Objectives: There is a recognized clinical association between nasal polyps and asthma. Nasal polyps and the airways of asthmatic patients demonstrate marked eosinophilia suggesting that this inflammatory cell may have a key role to play in both conditions. The objective of this study was to determine whether nasal polyps from patients with asthma had a greater density of activated eosinophils than patients with no associated respiratory disease. Design: Archived specimens were retrieved from patients who had undergone nasal polyp surgery and their case notes reviewed. Activated eosinophils were identified using immunohistochemistry for a monoclonal antibody to secreted eosinophil cationic protein (EG2). Setting: Teaching hospital otolaryngology unit. Participants: Consecutive patients who had undergone nasal polyp surgery in 1994 were recruited. The diagnosis of asthma was based on a documented physician diagnosis and appropriate drug treatment. Twenty‐four asthmatic and 35 non‐asthmatic patients were studied. Main outcome measures: Eosinophil density was measured using a standardized counting technique. Results: Asthmatic patients were significantly more likely to have had previous polyp surgery (chi‐square test: P < 0.05). Areas of intense eosinophilia were identified in all samples. There was a significant greater degree of activated eosinophilia in the asthmatic patients (t‐test: P < 0.05). Conclusions: We have demonstrated a higher number of previous operations in asthmatic patients, and also a greater degree of activated eosinophilia in asthmatic polyps compared with non‐asthmatics. This would suggest that eosinophil activity has a role to play in the pathogenesis of nasal polyps.     

EOS与COX-2在阿司匹林三联征患者鼻息肉组织中的表达及意义

目的:探讨嗜酸粒细胞(EOS)的聚集和COX-2在阿司匹林三联征(ST)发病过程中的调控作用。方法:取94例鼻内镜手术患者鼻息肉组织,其中ST患者34例(ST组),慢性鼻窦炎鼻息肉伴哮喘患者30例(ATA组),慢性鼻窦炎鼻息肉患者30例(对照组),应用苏木精-伊红染色及免疫组织化学SP法检测EOS的分布及COX-2的表达,并经统计学分析EOS、COX-2的表达和分布与临床病理和发病机制的关联。结果:EOS在3组患者鼻息肉组织中均大量浸润,EOS计数均数分别为80.02±6.11、76.62±5.22、65.97±4.78,ST组、ATA组分别与对照组比较差异均有统计学意义(均P<0.05),而ST组与ATA组比较差异无统计学意义(P>0.05)。COX-2在鼻息肉组织中主要表达于黏膜下腺体、腺上皮细胞、上皮细胞、血管内皮细胞及间质中的EOS,阳性细胞计数分别为88.13±6.26、89.46±5.97、91.22±4.11,ST组与对照组表达差异有统计学意义(P<0.05);ATA组表达与对照组比较差异无统计学意义(P>0.05);ST组与ATA组比较差异无统计学意义(P>0.05)。结论:EOS浸润程度不同可能是ST患者接触非甾体抗炎药后发生特有临床表现的炎症基础,COX-2在ST患者息肉组织中表达的差异可能与花生四烯酸代谢途径的转换及鼻息肉的形成有关。     

Basic fibroblast growth factor expression in recurrent versus non-recurrent nasal polyposis

Various growth factors are expressed in nasal polyps, and some of these have been suggested to play a role in polyp formation. A potential relation between growth factor expression and polyp recurrence, however, is undetermined. Basic fibroblast growth factor (bFGF) is expressed in mononuclear cells, as well as in endothelial and epithelial surface and gland cells of nasal polyps. To determine whether bFGF may play a role in the recurrence of nasal polyps, the present study aimed at a comparison of bFGF expression in recurrent versus non-recurrent polyps. Further, the expression in polyps from asthmatic patients was compared with that from non-asthmatics. Thirty patients with newly diagnosed nasal polyposis were included. Polypectomy was performed at entry to the long-term follow-up study. Fifteen patients only had one polypectomy (no recurrence group, with a median observation time of 81 months). Fifteen patients had a median of 6.4 polypectomies (multiple recurrence group, with a median observation time of 108 months). Five of nine patients with asthma belonged to the non-recurrence group and four to the recurrence group. The polyp from the entrance polypectomy was examined for expression of bFGF by immunohistochemistry, using a polyclonal antibody. A masked semi-quantification of staining intensity was performed in recurrent versus non-recurrent polyps, as well as in asthmatics versus non-asthmatics. bFGF expression was seen as varying staining of the polyp surface and gland epithelium, as well as of some mononuclear cells and some fibroblast-like cell profiles in the polyp stroma. Vascular endothelium was labeled occasionally. Semi-quantification of the staining intensity showed no significant differences between recurrent and non-recurrent polyps, or between asthmatics and non-asthmatics. We conclude that the level of immunohistochemical expression of bFGF in recurrent and non-recurrent nasal polyposis is equivalent. Thus, the level of bFGF expression in the primary polyp can not predict a subsequent recurrence. The expression of bFGF is not up-regulated in patients with asthma. Further studies are needed to determine a potential role of bFGF in nasal polyposis, with special reference to different stages of polyp formation and growth.     

Expression of vascular endothelial growth factor and transforming growth factor-beta 1 in nasal polyps]

OBJECTIVE: To study the expression and significance of vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) and transforming growth factor-beta 1(TGF-beta 1) in nasal polyps. METHODS: Expression of VEGF/VPF and TGF-beta 1 in nasal polyps from 34 patients and middle turbinates from 30 patients with deviation of nasal septum was prospectively studied with immunohistochemistry. Tissue sections were observed under optical microscope. RESULTS: (1) The VEGF/VPF positivity in vascular endothelium and in glandular cell was significantly higher in nasal polyps than in middle turbinates (P < 0.01 and P < 0.05, respectively); (2) The TGF-beta 1 positivity in extracellular matrix and in cells in the stroma was significantly higher in nasal polyps than in middle turbinates(P < 0.005); (3) The distribution and shape of TGF-beta 1 expressing cells in nasal polyps were similar to that of eosinophil, their positivities were significantly correlative; (4) The positivity of VEGF/VPF and TGF-beta 1 did not correlate with clinical type in nasal polyps (P > 0.05). CONCLUSION: (1) The VEGF/VPF may play a key role in the formation of heavy edema of nasal polyps; (2) The TGF-beta 1 may contribute to some of the pathologic changes observed in nasal polyps, such as thickening of the epithelial basement membrane and stromal fibrosis; (3) Eosinophils in nasal polyps represent a major source of TGF-beta 1.     

Hypoxia effects on vascular endothelial growth factor derived epithelial cells of nasal polyps]

OBJECTIVE: To understand the role of nasal mucous epithelial cells to hypoxia in early stage of nasal polyps(NP) formation. METHODS: Epithelial cells of NP and inferior turbinate (IT) were cultured without serum under normal oxygen and hypoxia, and stimulus of inflammatory cytokines. Erythropoietin (EPO) was regarded as hypoxia mark, and expression of vascular endothelial growth factor(VEGF) mRNA and protein derived from epithelial cells were detected respectively by in situ hybridization and ELISA. RESULTS: 1. Under hypoxia, EPO mRNA was expressed intensely in epithelial cells from NP and IT, and there was no significant difference between both of them. This result suggested that EPO might be regarded as a hypoxic mark. 2. The ability of producing VEGF mRNA increased with cytokines stimulation, especially under hypoxia. Protein level of VEGF from epithelial cells of NP and IT increased with cytokines stimulation, especially in hypoxia and was time-dependent. CONCLUSION: Epithelial cells actively produce vast VEGF under hypoxia. The VEGF induced by hypoxia of the mucosa in middle meatus is of importance in the formation of nasal polyps(NP) in early stage, which may be the major cause of NP formation in middle meatus.     

鼻息肉中一氧化氮合酶表达及其意义

目的 :了解鼻息肉 (NP)中一氧化氮合酶 (NOS)的分布特点和活性及其在NP发病中的作用。方法 :用免疫组织化学法检测 30例NP(NP组 )及 2 0例正常鼻黏膜 (正常鼻黏膜组 )中NOS的表达 ,并用分光光度计法检测其活性。结果 :NP组NOS活性为 (4.0 79± 0 .6 5 5 )U/mg蛋白 ,正常鼻黏膜组为 (1.5 2 6± 0 .310 )U/mg蛋白 ,二者间差异有统计学意义 (P <0 .0 1) ;NP组iNOS有大量细胞表达 ,分布在黏膜上皮、腺体和血管内皮细胞以及炎症细胞中 ,与正常鼻黏膜组比较 ,差异有统计学意义 (P <0 .0 1) ;而eNOS也有表达 ,但与正常鼻黏膜组比较 ,差异无统计学意义 ;NP组i NOS表达明显高于eNOS表达 ,其差异有统计学意义 (P <0 .0 1)。结论 :NP主要表达iNOS ,分布在黏膜上皮、腺体和血管内皮细胞以及炎症细胞中 ,其产生的大量一氧化氮在NP的发病过程中可能起着重要的作用     

鼻息肉中血管内皮生长因子mRNA的检测与意义

目的 :检测鼻息肉组织和鼾症下鼻甲粘膜组织中的血管内皮生长因子 (VEGF) m RN A水平的表达 ,了解其在慢性炎症过程中的作用。方法 :取 6例行下鼻甲切除术的下鼻甲粘膜和 7例鼻息肉切除术的鼻息肉标本 ,用半定量的反转录 -聚合酶链反应 (RT- PCR)方法检测 VEGF的 m RNA表达。结果 :RT- PCR结果显示在鼻息肉组织中 V EGF的表达较鼾症患者下鼻甲粘膜组织明显升高。结论 :鼻息肉组织中 VEGF的表达显著升高 ,推测 VEGF在鼻息肉的形成、生长及复发过程中具有极其重要的作用。     

Immunohistochemical expression of VEGF and VEGF receptors in nasal polyps as compared to normal turbinate mucosa

The factors involved in the development of chronic inflammation and edema in nasal polyps remain to be clarified. The expression of vascular endothelial growth factor (VEGF) has been described in plasma cells, suggesting that plasma cells may play a major role in the development of edema in nasal polyps through the production of VEGF. We performed immunohistochemical analysis using specific antibodies to VEGF and to the known VEGF receptors, VEGFR-1 and VEGFR-2, on paraffin sections of human nasal polyps ( n=11) and controls of human mucosa of the normal middle turbinates ( n=6). In normal turbinate mucosa, sporadic immunostaining for VEGF was observed throughout the endothelial cells of the small veins and arteries. VEGFR-1 and VEGFR-2 expression was faint in the healthy turbinates. In nasal polyp tissues, strong immunostaining for VEGF was found in the endothelium of blood vessels and in the infiltrating perivascular inflammatory cells. Fibroblasts also stained for VEGF. Strong immunolabeling to VEGFR-1 was evident in the vascular endothelium, whereas weak to moderate VEGFR-1-staining was generally confined to scattered mononuclear round cells. Mononuclear round cells and the endothelium of capillaries revealed immunoreactivity to VEGFR-2. These findings support a role for VEGF and its receptors, VEGFR-1 and VEGFR-2, in the development and perpetuation of edema and angiogenesis in nasal polyps.     

Fas及Bcl-2在鼻息肉组织中的表达及意义

目的：探讨Fas和Bcl 2在鼻息肉组织中的表达及与鼻息肉发病的关系。方法：应用S P免疫组化法检测36例鼻息肉组织及19例下鼻甲组织中Fas和Bcl 2的表达情况。结果： （1）Fas在鼻息肉上皮及腺上皮的表达弱于对照组（P＜0.05）；（2）Bcl 2在鼻息肉上皮及腺上皮的表达强于对照组（P＜0.05）；（3）鼻息肉上皮细胞中Fas、Bcl 2蛋白的表达无相关性（P＞0.05）。结论：（1）Fas和 Bcl 2在鼻息肉发生发展中起重要作用；（2）在NP上皮细胞中， Fas和Bcl 2无相关性，因此这两种凋亡基因在NP的形成过程中各起独立作用，协调抑制NP上皮细胞的凋亡。     

黏附分子及血管内皮生长因子在鼻息肉中的表达

目的 探讨细胞间黏附分子-1（ICAM-1）、血管细胞黏附分子-1（VCAM-1）以及血管内皮生长因子（VEGF）在鼻息肉中的表达与意义。方法25例鼻息肉标本和9例下鼻甲黏膜标本，分别行ICAM-1、VCAM-1、VEGF免疫组化染色和HE染色，光镜下观察比较各种分子表达水平。结果 鼻息肉中可见大量嗜酸性粒细胞（EOS）浸润。ICAM-1、VCAM-1和VEGF均可表达于鼻息肉血管内皮、间质及炎症细胞，且在鼻息肉血管内皮、间质及浸润炎症细胞中的表达趋势呈现正相关关系。结论 ICAM-1、VCAM-1可能与EOS等炎症细胞附壁浸润活化过程关系密切，VEGF可能启动并加强这一病理变化。它们的协同作用可能参与了鼻息肉的病理过程。     

鼻息肉中单核细胞趋化蛋白1和血管内皮生长因子的表达

目的明确单核细胞趋化蛋白1（monocyte chemotactic protein 1，MCP-1）和血管内皮生长因子（vascular endothelial growth factor，VEGF）在鼻息肉组织中的表达及其相关性，初步探讨MCP-1与鼻息肉发生的关系。方法取40例鼻息肉组织和25例下鼻甲组织，应用原位杂交和免疫组织化学等方法检测MCP-1和VEGF mRNA及蛋白质的表达。结果鼻息肉组织中MCP-1和VEGF mRNA及蛋白质的表达均高于对照组下鼻甲组织（P值均〈0．01）；鼻息肉组织中MCP-1和VEGF蛋白质的表达呈正相关（r=0．871，P〈0．05）。结论鼻息肉组织中MCP-1和VEGF表达增加，二者协同作用可能是鼻息肉形成的原因之一。     

New immunohistologic findings on the differential role of cyclooxygenase 1 and cyclooxygenase 2 in nasal polyposis

BACKGROUND: Cyclooxygenase 1 (Cox-1) plays a key role in arachidonic acid metabolism and in the pathophysiology and immunology of nasal polyposis in patients suffering from aspirin intolerance. We hypothesize that Cox-2 also might be relevant in the etiology of nasal polyps of aspirin-tolerant patients by their effects on inflammatory mediators as well as on microvascular permeability. METHODS: Fifty-two surgical specimens were immunohistochemically labeled for Cox-1 and Cox-2. Specimens were taken from chronically inflamed mucosa (n = 19) and from nasal polyps (n = 19) during endonasal sinus surgery. Controls were obtained from healthy nasal respiratory mucosa (n = 14), harvested during turbinate surgery in patients with nasal obstruction without inflammatory disease. Staining intensities were semiquantitatively assessed and statistically analyzed. RESULTS: In chronically inflamed tissue the expression of Cox-1 and Cox-2 was strongly labeled. However, in nasal polyps the staining pattern of Cox-1 was similar, but Cox-2 expression in epithelial cells was significantly less than in inflamed, nonpolypous specimens. CONCLUSION: These data suggest that while Cox-1 is strongly up-regulated, Cox-2 expression is significantly lower in epithelial cells of nasal polyps than in those of chronic sinusitis without polyps. The relevance of this finding has to be discussed with respect to the regulatory function of Cox on the inflammatory reaction in nasal respiratory mucosa and its hypothetical role in alterations of capillary permeability via vascular permeability factor/vascular endothelial growth factor.     

鼻息肉调节激活正常T细胞表达和分泌因子的测定及其意义

目的 探讨在鼻息肉形成过程中,上皮应答时产生调节激活正常Ｔ细胞表达和分泌因子（ｒｅｇｕｌａｔｅｄ ｕｐｏｎ ａｃｔｉｖａｔｉｏｎ,ｎｏｒｍａｌＴｃｅｌｌ ｅｘｐｒｅｓｓｅｄ ａｎｄ ｓｅｃｒｅｔｅｄ,ＲＡＮＴＥＳ）对嗜酸粒细胞趋化、移行、局部聚集的影响。方法 采用无血清原代细胞培养法培养鼾症患者下鼻甲上皮细胞和鼻息肉上皮细胞,经炎性介质ＩＬ－１β（２５ｕｇ／Ｌ,５０ｕｇ／Ｌ）刺激后收集２４ｈ和４８