Roles of vascular endothelial growth factor, Angiopoietin 1, and Angiopoietin 2 in nasal polyp

The Effect of Bevacizumab and Propranolol on Nasal Polyposis

OBJECTIVE

This study aims to evaluate the effects of bevacizumab and propranolol from the point of view of a possible antiangiogenic effect in a model of primary nasal polyp (NP) tissue culture.

METHODS

NP samples of 21 patients and normal healthy nasal mucosa samples of 7 patients were cultured. Samples were divided into four groups as follows (healthy nasal mucosa, NP without any treatment, NP treated with propranolol, NP treated with bevacizumab). Cultured tissues were formalin fixed and paraffin embedded. Tissue sections and immunohistochemical VEGF-A, angiopoietin-1 (Ang-1), and angiopoietin-2 (Ang-2) expressions were evaluated. ELISA was also performed for each one of them.

RESULTS

Both propranolol and bevacizumab significantly decreased the expressions of VEGF-A and Ang-1, and they significantly increased the expression of Ang-2 in comparison to the control NP group. In the healthy nasal mucosa group, no significant expression of VEGF-A was seen, a slight (+) Ang-1 expression, and a high (+++) Ang-2 expression were observed.

CONCLUSION

Bevacizumab and propranolol exert an antiangiogenic effect on NP tissues, mainly by decreasing VEGF-A and Ang-1 expression, increasing Ang-2 expression.

Vitamin K2 Ameliorates Damage of Blood Vessels by Glucocorticoid: a Potential Mechanism for Its Protective Effects in Glucocorticoid-induced Osteonecrosis of the Femoral Head in a Rat Model

Glucocorticoid has been reported to decrease blood vessel number and harm the blood supply in the femoral head, which is recognized to be an important mechanism of glucocorticoid-induced osteonecrosis of the femoral head (ONFH). To prevent glucocorticoid-induced ONFH, medication that promotes both bone formation and angiogenesis would be ideal. Vitamin K2 has been revealed to play an important role in bone metabolism; however, few studies have focused on the effect of Vitamin K2 on new vascular formation. Thus, this study aimed to investigate whether Vitamin K2 promoted new blood vessel formation in the presence of glucocorticoids, both in vitro and in vivo. The effect of Vitamin K2 on viability, migration, in vitro tube formation, and VEGF, vWF, CD31, KDR, Flt and PDGFB in EAhy926 incubated with or without dexamethasone were elucidated. VEGF, TGF-β and BMP-2, angiogenesis-related proteins secreted by osteoblasts, were also detected in the osteoblast-like cell line of MG63. In addition, blood vessels of the femoral head in rats administered with or without methylprednisolone and Vitamin K2 were evaluated using angiography and CD31 staining. In vitro studies showed that Vitamin K2 significantly protected endothelial cells from dexamethasone-induced apoptosis, promoted endothelial cell migration and in vitro tube formation. Angiogenesis-related proteins both in EAhy926 and MG63 were also upregulated by Vitamin K2 when cotreated with dexamethasone. In vivo studies showed enhanced blood vessel volume and CD31-positive staining cells in rats cotreated with VK2 and methylprednisolone compared to rats treated with methylprednisolone only. Collectively, Vitamin K2 has the ability to promote angiogenesis in vitro and to ameliorate vessels of the femoral head in glucocorticoid-treated rats in vivo, indicating that Vitamin K2 is a promising drug that may be used to prevent steroid-induced ONFH.

Cellular proliferation and angiogenesis in nasal polyps of young adult and geriatric patients

BACKGROUND

Cellular proliferation and angiogenesis are associated with pathophysiology of nasal polyposis (NP). In a previous report, we showed that patient age is a predictive factor of surgical outcomes among patients with chronic rhinosinusitis and NP, and that geriatric patients exhibit better outcomes than pediatric and adult patients. We postulated that better outcomes in the geriatric population may be secondary to decreased proliferation and angiogenesis within polyps. Therefore, we evaluated the cellular proliferation and angiogenesis in young adult and geriatric patients with NP. This was a prospective case-control study.

METHODS

Twenty patients were divided into 2 groups according to age (20 to 30 years vs ≥65 years of age). NP tissues were sampled during endoscopic sinus surgery and processed for immunohistochemistry. Cellular proliferation was evaluated with proliferating cell nuclear antigen and Ki67, and angiogenesis was assessed with vascular endothelial growth factor. We also compared objective surgical outcomes using endoscopy scores.

RESULTS

Immunohistochemical analysis revealed significantly higher expression and positive reactivity of proliferating cell nuclear antigen and Ki67 in the polyps of young adults than in those of geriatric patients, whereas the expression of vascular endothelial growth factor was similar between the 2 groups. Endoscopy scores were better in the geriatric group.

CONCLUSION

Geriatric patients have a lower cellular proliferative ability than young adults, and angiogenesis does not significantly differ between the 2 age groups. Cellular proliferation seems to be the cause of the different surgical outcomes between the 2 age groups, whereas angiogenesis has no significant influence on the postoperative course.

Deprived TLR9 expression in apparently healthy nasal mucosa might trigger polyp-growth in chronic rhinosinusitis patients

Background

The origin of nasal polyps in chronic rhinosinusitis is unknown, but the role of viral infections in polyp growth is clinically well established. Toll-like receptors (TLRs) have recently emerged as key players in our local airway defense against microbes. Among these, TLR9 has gained special interest in viral diseases. Many studies on chronic rhinosinusitis with nasal polyps (CRSwNP) compare polyp tissue with nasal mucosa from polyp-free individuals. Knowledge about changes in the turbinate tissue bordering the polyp tissue is limited.

Objectives

To analyse the role of TLR9 mediated microbial defense in tissue bordering the polyp.

Methods

Nasal polyps and turbinate tissue from 11 patients with CRSwNP and turbinate tissue from 11 healthy controls in total were used. Five biopsies from either group were analysed immediately with flow cytometry regarding receptor expression and 6 biopsies were used for in vitro stimulation with a TLR9 agonist, CpG. Cytokine release was analysed using Luminex. Eight patients with CRSwNP in total were intranasally challenged with CpG/placebo 24 hours before surgery and the biopsies were collected and analysed as above.

Results

TLR9 expression was detected on turbinate epithelial cells from healthy controls and polyp epithelial cells from patients, whereas TLR9 was absent in turbinate epithelial cells from patients. CpG stimulation increased the percentage cells expressing TLR9 and decreased percentage cells expressing VEGFR2 in turbinate tissue from patients. After CpG stimulation the elevated levels of IL-6, G-CSF and MIP-1β in the turbinate tissue from patients were reduced towards the levels demonstrated in healthy controls.

Conclusion

Defects in the TLR9 mediated microbial defense in the mucosa adjacent to the anatomic origin of the polyp might explain virus induced polyp growth. CpG stimulation decreased VEGFR2, suggesting a role for CpG in polyp formation. The focus on turbinate tissue in patients with CRSwNP opens new perspectives in CRSwNP-research.

Vascular endothelial growth factor receptor 1 expression in nasal polyp tissue

BACKGROUND

Edema represents a key feature of nasal polyp (NP) disease. Members of the vascular endothelial growth factor (VEGF) family may be involved, but the precise role of VEGF-A, VEGF-B, placental growth factor (PlGF), and their receptors VEGFR1 and VEGFR2 in NP edema formation remains elusive.

OBJECTIVE

Exploring the expression of VEGF family members and their receptors and their correlation with clinical, radiological, and edema markers in NP.

METHODS

The expression of VEGF-A, VEGF-B, PlGF, VEGFR1, and VEGFR2 was measured in NP (n = 23) and control tissue (n = 22) at mRNA and protein level. Edema was evaluated by measuring albumin levels and wet/dry ratios. Computed tomography (CT) scans were scored using the Lund-Mackay scoring system. IL-5 mRNA expression was determined by real-time RT-PCR. Cell suspensions from NP (n = 10) and control tissue (n = 12) were stimulated in vitro with IL-1β or TNFα.

RESULTS

mRNA expression of VEGFR1 and VEGF-B was significantly higher in NP compared with control tissue. Expression levels of VEGF-B and VEGFR1 significantly correlated with NP albumin content (VEGF-B: P = 0.0208; VEGFR1: P = 0.0293), CT scan scores (VEGF-B: P = 0.0075; VEGFR1: P = 0.0068), and IL-5 mRNA (VEGF-B: P = 0.0027; VEGFR1: P = 0.0001). In vitro stimulation of control and NP tissue cell suspensions with IL-1β or TNFα significantly reduced the expression of VEGFR2 in control tissue, without altering VEGFR1 and VEGF-B expression. hVEGF-B induced nitric oxide production in NP macrophages (P < 0.05).

CONCLUSION

Expression levels of VEGFR1 and VEGF-B correlate with edema and clinical markers of NP disease and therefore represent potential therapeutic targets.

The effect of corticosteroid therapy on cyclooxygenase 2, vascular endothelial growth factor, and inducible nitric oxide synthase expression levels in nasal polyposis

Nasal and oral corticosteroid therapy is the ultimate treatment for sinonasal polyposis. Although there are numerous clinical studies regarding the factors associated with the formation of nasal polyposis, there is not enough literature on how these factors are influenced by steroid treatment. Twenty-one patients that had no prior medical therapy for nasal polyposis or had received medical therapy at least 6 months earlier were included in the study. Patients were treated with oral and nasal corticosteroid therapy. Nasal polyp biopsies were taken before and after medical treatment and immunohistochemical staining for cyclooxygenase 2 (COX-2), vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS) were applied to the specimens. In this study, we tried to demonstrate the effects of corticosteroid therapy on nasal polyposis tissue immunohistochemically. There was no change at immunohistochemical expression level of COX-2; however, the decline of immunohistochemical expression levels of VEGF and iNOS was statistically significant. Short-term steroid therapy does not affect COX-2 level of the nasal polyposis tissue, but has an influence on iNOS and VEGF levels. Our findings were harmonious with those of the previous studies of the literature. Further studies are needed to demonstrate the long-term effects with a larger patient group.

Effects of Histone Deacetylase Inhibitor on Extracellular Matrix Production in Human Nasal Polyp Organ Cultures

Background

Nasal polyposis is associated with a chronic inflammatory condition of the sinonasal mucosa and involves myofibroblast differentiation and extracellular matrix (ECM) accumulation. Epigenetic modulation by histone deacetylase (HDAC) inhibitors including trichostatin A (TSA) has been reported to have inhibitory effects on myofibroblast differentiation in lung and renal fibroblasts. The purpose of this study was to investigate the inhibitory effect of TSA on myofibroblast differentiation and ECM production in nasal polyp organ cultures.

Methods

Nasal polyp tissues from 18 patients were acquired during endoscopic sinus surgery. After organ culture, nasal polyps were stimulated with TGF-beta1 and then treated with TSA. Alpha-smooth muscle actin (α-SMA), fibronectin, and collagen type I expression levels were examined by reverse transcription–polymerase chain reaction (PCR), real-time PCR, Western blot, and immunofluorescent staining. HDAC2, HDAC4, and acetylated H4 expression levels were assayed by Western blot. Cytotoxicity was analyzed by the terminal deoxynucleotidyl transferase biotin–dUTP nick end labeling assay.

Results

The expression levels of α-SMA, fibronectin, and collagen type 1 were increased in nasal polyp after transforming growth factor (TGF) beta1 treatment. TSA-inhibited TGF-beta1 induced these gene and protein expression levels. Furthermore, TSA suppressed protein expression levels of HDAC2 and HDAC4. However, TSA induced hyperacetylation of histones H4. Treatment with TGF-beta1 with or without TSA did not have cytotoxic effect.

Conclusion

These findings provide novel insights into the epigenetic regulation in myofibroblast differentiation and ECM production of nasal polyp. TSA could be a candidate of a therapeutic agent for reversing the TGF-beta1–induced ECM synthesis that leads to nasal polyp development.

Effects of methotrexate on vascular endothelial growth factor, angiopoietin 1, and angiopoietin 2 in nasal polyps

BACKGROUND

Methotrexate (MTX) is a very effective treatment for chronic inflammatory diseases, which are often associated with increased angiogenesis. Angiogenesis is dependent on a perfectly coordinated balance between endogenous-positive and -negative regulatory factors, including vascular endothelial growth factor (VEGF) and the angiopoietins (Ang). The aim of this study was to investigate the effects of MTX on levels of VEGF, Ang-1, and Ang-2 in organ-cultured nasal polyps (NPs).

METHODS

To determine the effects of MTX, NP tissues were cultured using an air-liquid interface method. Cultures were maintained in the absence or presence of MTX (10 or 100 micromoles) for 24 hours. Hematoxylin and eosin, and TUNEL (terminal deoxynucleotidyl transferase [Tdt]-mediated dUTP-biotin nick-end labeling) staining were performed to observe apoptosis. Enzyme-linked immunosorbent assay was used to quantify tissue concentrations of VEGF, Ang-1, and Ang-2.

RESULTS

MTX treatment resulted in marked alterations in inflammatory cells, especially eosinophils. In contrast, the mucosal epithelium, microvessels including arterioles, veins and capillaries, and fibroblasts maintained their structure. TUNEL(+) cells (apoptotic cells) were seen in the MTX-treated specimens. The more induction of TUNEL(+) cells was observed 100-micromolar MTX-treated specimens. VEGF and Ang-1 levels were significantly lower, and Ang-2 levels were significantly higher in NPs treated with 100-micromolar MTX than in nontreated NPs (p < 0.01).

CONCLUSION

MTX may inhibit the growth of NPs via local regulation of VEGF, Ang-1, and Ang-2 protein levels. We suggest that MTX can be used to treat NPs.

Increased expression of the chemokine CCL23 in eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous chronic disease characterized by local inflammation of the sinonasal tissues. The pathogenesis of CRS remains controversial, but it has been associated with the accumulation of various immune and inflammatory cells in sinus tissue.

OBJECTIVES

The objective of this study was to investigate the expression of the chemokine CCL23, which is known to bind to CCR1 and recruit monocytes, macrophages, and dendritic cells, in patients with CRS.

METHODS

We collected nasal tissue from patients with CRS and control subjects. We assayed mRNA for CCL23 by using real-time PCR and measured CCL23 protein by means of ELISA, immunohistochemistry, and immunofluorescence.

RESULTS

CCL23 mRNA levels were significantly increased in nasal polyps (NPs) from patients with CRS with nasal polyps (CRSwNP; P < .05) compared with inferior turbinate and uncinate tissue from patients with CRS or control subjects. CCL23 protein levels were also increased in NPs, although these levels were not statistically significant. Immunohistochemical analysis revealed CCL23 expression in mucosal epithelial cells and inflammatory cells, but accumulation of CCL23(+) inflammatory cells occurred only in NPs. Immunofluorescence data showed CCL23 colocalization with eosinophil cationic protein-positive eosinophils. The concentration of CCL23 in NPs positively correlated with the concentration of eosinophil cationic protein, suggesting that eosinophils are major CCL23-producing cells in NPs. Finally, we found that CCL23 protein levels were significantly increased in NPs from patients with CRSwNP with aspirin sensitivity.

CONCLUSION

Overproduction of CCL23 in NPs might contribute to the pathogenesis of eosinophilic CRSwNP through the recruitment of CCR1(+) inflammatory cells, including monocytes and macrophages, and the amplification of local inflammation.