prostaglandin-d2 and Nasal-Polyps

Aspirin-exacerbated respiratory disease (AERD) is characterized by chronic eosinophilic nasal polyps, asthma, and airway reactions upon cyclooxygenase (COX) 1 inhibition. AERD is present in up to 7% of adult patients with asthma and the underlying pathogenesis remains largely elusive but prostaglandin D2, cysteinyl leukotrienes, mast cells, and type 2 cytokines are thought to contribute. A wealth of studies have recently implicated group 2 innate lymphoid cells (ILC2), a novel lineage-negative lymphocyte population that produces type 2 cytokines, in human allergic disease pathogenesis. Importantly, our recent work identified that ILC2s are recruited to the nasal mucosa of patients on AERD after COX-1 inhibitor administration. Here, we review the potential impact of ILC2s in the development and propagation of type 2 inflammation in AERD.

Topics: Adult; Asthma, Aspirin-Induced; Cyclooxygenase 1; Cytokines; Eosinophils; Humans; Immunity, Innate; Inflammation; Lymphocytes; Mast Cells; Nasal Mucosa; Nasal Polyps; Prostaglandin D2; Th2 Cells

The relationship between rhinitis and chronic sinusitis is close and complex and may perhaps show many points of view, anatomical and physiological, epidemiological (by comparing the prevalence of an ailment in carriers of another ailment), experimental (by making nasal allergen provocation tests and studying the sinus anomalies induced) and physiopathological (by phenotyping and comparison of the inflammation present with one another and other ailments). If the results of these studies are convincing, there is still lack of formal proof that confirms the fundamental role of nasal inflammation in general and in particular allergic inflammation in the genesis of sinusitis.

Topics: Allergens; Chronic Disease; Cytokines; Eosinophilia; Humans; Leukocytes; Nasal Mucosa; Nasal Polyps; Nasal Provocation Tests; Paranasal Sinuses; Prevalence; Prostaglandin D2; Radiography; Respiratory Hypersensitivity; Rhinitis; Sinusitis

Systemic reactions are related to the pathogenesis of Aspirin Exacerbated Respiratory Disease (AERD). With this work we wanted to study the changes in the systemic levels of inflammatory mediators in both baseline and after oral aspirin challenge in patients with and without AERD.. Patients with nasal polyposis and asthma with AERD (n=20) and without (n=18) were orally challenged with aspirin in a single-blind placebo controlled study. Serum samples and urine were collected before and 6h after placebo and aspirin oral challenges. Serum levels of inflammatory mediators were assayed by using the Luminex technology and ELISA. The concentrations of 9-alpha, 11-beta prostaglandin F2, and leukotriene E4 (uLTE4) were measured in urine samples by ELISA. The expression of T-cell surface markers was analyzed in peripheral blood mononuclear cells isolated before and after the challenges.. AERD patients showed significantly higher baseline levels of s-IL-5R-alpha, uLTE4 and percentage of CD4(+)CD25(+)CD127(pos) and CD4(+)CD45RA(-)CD45RO(+) but decreased levels of TGF-β1 and number of CD4(+)CD25(+)CD127(neg) cells. Aspirin challenge induced the release of uLTE4, IL-6 and increased the number of CD4(+)CD45RA(-)CD45RO(+) memory T-cells only in AERD patients but failed to reduce the levels of sCD40L as observed in non-AERD subjects. Further, IL-8 and sIL-5R-alpha levels directly correlated with the PD20ASA and the effects of aspirin on IL-6 and number of memory T-cells was more pronounced in subjects showing more strong reaction (bronchial and nasal).. AERD patients have a differential baseline inflammatory pattern that supports the role inflammation as underlying mechanism of the disease. Systemic response to oral aspirin challenge was related to an increase in serum IL-6 and the number of circulating memory T-cells in AERD patients.

Topics: Adult; Anti-Inflammatory Agents, Non-Steroidal; Aspirin; Asthma, Aspirin-Induced; Chronic Disease; Cytokines; Female; Humans; Immunoenzyme Techniques; Inflammation Mediators; Leukotriene E4; Male; Middle Aged; Nasal Polyps; Prostaglandin D2; Rhinitis; Single-Blind Method; Sinusitis; T-Lymphocyte Subsets

Numerous open trials have demonstrated the beneficial clinical effects of aspirin desensitization (AD) in patients with aspirin-induced asthma (AIA). These beneficial effects might be attributable to aspirin's potent anti-inflammatory properties, but that supposition requires further corroboration.. We sought to compare the clinical and biochemical responses to chronic oral AD in 20 patients with AIA and 14 patients with aspirin-tolerant asthma (ATA). All of the patients had chronic rhinosinusitis and nasal polyposis, and these responses were investigated in a pilot, double-blind, placebo-controlled study.. Twelve patients with AIA and 6 patients with ATA were randomly assigned to receive 624 mg of aspirin, and 8 patients with AIA and 8 patients with ATA received placebo. Both aspirin and placebo were administered once daily for 6 months. Nasal symptoms, Sino-Nasal Outcome Test (SNOT20) scores, peak nasal inspiratory flows, Asthma Control Questionnaire scores, spirometric parameters, peak expiratory flows, blood eosinophilia, and corticosteroid doses were assessed on a monthly basis. Levels of urinary leukotriene E4 and the stable plasma prostaglandin (PG) D2 metabolite 9α,11β-PGF2 were evaluated at baseline and after 1, 3, 5, and 6 months.. Only the patients with AIA subjected to AD reported improvements in smell and reductions in sneezing and nasal blockade. The SNOT20 and Asthma Control Questionnaire scores of these patients decreased, and their peak nasal inspiratory flows increased. The dosages of inhaled corticosteroids were reduced. There were no changes in leukotriene E(4) or 9α,11β-PGF(2) levels after AD.. The clinically beneficial effects of AD on nasal and bronchial symptoms occurred only in the patients with AIA.

Topics: Administration, Oral; Adult; Aged; Allergens; Aspirin; Asthma; Asthma, Aspirin-Induced; Chronic Disease; Desensitization, Immunologic; Dinoprost; Double-Blind Method; Eosinophils; Female; Follow-Up Studies; Humans; Leukotriene E4; Male; Middle Aged; Nasal Polyps; Pilot Projects; Prostaglandin D2; Rhinitis; Sinusitis; Spirometry; Treatment Outcome

Prostaglandins and leukotrienes are implicated in conditions of both the upper and lower airways. In the former they are deranged in nasal polyposis, intrinsic rhinitis and allergic rhinitis while in the latter they are involved in the pathogenesis of asthma. The aim of the present study was to measure mucosal eicosanoid levels in the three types of rhinitis and compare with controls. In addition, the effect of topical steroids on eicosanoid levels in rhinitis was examined. The levels of prostaglandins E(2) (PGE(2)) and D(2) (PGD(2)) and of leukotrienes E(4) (LTE(4)) and B(4) (LTB(4)) were measured in nasal biopsies from the inferior turbinates of patients suffering from perennial rhinitis and a control group. Rhinitis patients were classified into three categories: perennial allergic rhinitis (PAR), non-allergic rhinitis with eosinophilia (NARES) and noneosinophilic non-allergic rhinitis (NENAR) on the basis of symptoms, secretion eosinophilia, nasal resistance and allergy testing. Patients with rhinitis were randomized into two groups. One received fluticasone propionate nasal spray (FPANS) and the other a placebo (PNS) over a period of six weeks prior to the biopsies. One hundred and one patients with PAR, NARES or NENAR were recruited sequentially and the control group consisted of 21 patients with no evidence of rhinitis but with nasal obstruction due to septal deviation. Untreated rhinitics had significantly lower levels of PGE(2), PGD(2) and LTE(4) than non-rhinitic controls. Six-weeks' treatment with FPANS significantly increased the levels of those eicosanoids in patients with PAR and NARES but they were still significantly below normal. Levels of LTB(4) in all three rhinitis groups were not significantly different from controls and treatment with topical steroids had no effect. Their findings are contrary to current thinking that increased levels of eicosanoids, in particular cysteinyl-leukotrienes, play an important role in the pathogenesis of chronic, non-infective upper airway inflammation.

Topics: Airway Resistance; Androstadienes; Anti-Inflammatory Agents; Chronic Disease; Dinoprostone; Double-Blind Method; Eosinophils; Fluticasone; Humans; Leukocyte Count; Leukotriene B4; Leukotriene E4; Leukotrienes; Nasal Mucosa; Nasal Polyps; Prostaglandin D2; Prostaglandins; Rhinitis; Rhinitis, Allergic, Perennial

Histamine antagonists together with topical steroids are the treatment of choice in allergic rhinitis. Many of these histamine antagonists exhibit effects in addition to blockade of the histamine receptor. In this study we have investigated the effects of ebastine and carebastine on the release of eicosanoids and cytokines from human dispersed polyp cells and the effect of these compounds on the release of inflammatory mediators into nasal lavage fluid after allergen challenge. Ebastine was shown to block the release of anti-IgE-induced prostaglandin D2 (PGD2) and leukotriene C4/D4 from human nasal polyp cells (IC30 values of 2.57 and 9.6 mumol/L, respectively) and to inhibit the release of cytokines. Carebastine inhibited the release of PGD2 (IC30 8.14 mumol/L) but had little effect on cytokine release. When patients underwent nasal provocation tests with allergen, ebastine significantly increased the mean number of pollen grains required to induce an allergic response. In addition, the drug inhibited the release of granulocyte-macrophage colony-stimulating factor but had no effect on any other mediators measured.

Topics: Adolescent; Adult; Allergens; Butyrophenones; Cross-Over Studies; Double-Blind Method; Female; Granulocyte-Macrophage Colony-Stimulating Factor; Histamine H1 Antagonists; Humans; Leukotriene C4; Male; Middle Aged; Nasal Polyps; Piperidines; Pollen; Prostaglandin D2; Rhinitis, Allergic, Seasonal

Topics: Aspirin; Cytokines; Humans; Japan; Nasal Polyps; Prostaglandin D2; Thymic Stromal Lymphopoietin

Prostaglandin (PG) D2 is the dominant COX product of mast cells and is an effector of aspirin-induced respiratory reactions in patients with aspirin-exacerbated respiratory disease (AERD).. We evaluated the role of the innate cytokine thymic stromal lymphopoietin (TSLP) acting on mast cells to generate PGD2 and facilitate tissue eosinophilia and nasal polyposis in patients with AERD.. Urinary eicosanoid levels were measured in aspirin-tolerant control subjects and patients with AERD. Nasal polyp specimens from patients with AERD and chronic rhinosinusitis were analyzed by using quantitative PCR, Western blotting, and immunohistochemistry. Human cord blood-and peripheral blood-derived mast cells were stimulated with TSLP in vitro to assess PGD2 generation.. Urinary levels of a stable PGD2 metabolite (uPGD-M) were 2-fold higher in patients with AERD relative to those in control subjects and increased further during aspirin-induced reactions. Peak uPGD-M levels during aspirin reactions correlated with reductions in blood eosinophil counts and lung function and increases in nasal congestion. Mast cells sorted from nasal polyps expressed PGD2 synthase (hematopoietic PGD2 synthase) mRNA at higher levels than did eosinophils from the same tissue. Whole nasal polyp TSLP mRNA expression correlated strongly with mRNA encoding hematopoietic PGD2 synthase (r = .75), the mast cell-specific marker carboxypeptidase A3 (r = .74), and uPGD-M (r = 0.74). Levels of the cleaved active form of TSLP were increased in nasal polyps from patients with AERD relative to those in aspirin-tolerant control subjects. Recombinant TSLP induced PGD2 generation by cultured human mast cells.. Our study demonstrates that mast cell-derived PGD2 is a major effector of type 2 immune responses driven by TSLP and suggests that dysregulation of this innate system contributes significantly to the pathophysiology of AERD.

Topics: Adult; Aged; Asthma, Aspirin-Induced; Cells, Cultured; Cytokines; Eosinophilia; Female; Humans; Leukocyte Count; Male; Mast Cells; Middle Aged; Nasal Polyps; Prostaglandin D2; Prostaglandins D; Rhinitis; Sinusitis; Thymic Stromal Lymphopoietin; Young Adult

Topics: Aspirin; Asthma; Cyclooxygenase 1; Cyclooxygenase Inhibitors; Dinoprostone; Homeostasis; Humans; Nasal Polyps; Prostaglandin D2; Sinusitis

Vascular endothelial growth factor (VEGF) is known to be associated with the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). VEGF is produced by a variety of cells including fibroblasts. It was recently reported that prostaglandin (PG) E. 5 μM of PGD. PGD

Topics: Adult; Aged; Aged, 80 and over; Cells, Cultured; Eosinophils; Female; Fibroblasts; Gene Expression; Humans; Immunoglobulin E; Leukocyte Count; Male; Middle Aged; Nasal Polyps; Prostaglandin D2; Receptors, Immunologic; Receptors, Prostaglandin; Respiratory Function Tests; RNA, Messenger; Vascular Endothelial Growth Factor A

PGD₂ has long been implicated in allergic diseases. Recent cloning of a second PGD₂ receptor, DP2 (also known as CRTh2), led to a greater understanding of the physiological and pathophysiological implications of PGD₂. PGD₂ signaling through DP1 and DP2 mediates different and often opposite effects in many cell types of the immune system. Although mast cells (MC) are the largest source of PGD₂ in the body, there is little information about their potential expression of DP2 and its functional significance. In this study, we show that tissue MC in human nasal polyps express DP2 protein, and that human MC lines and primary cultured human MC express mRNA as well as protein of DP2. By immunohistochemistry, we detected that 34% of MC in human nasal polyps expressed DP2. In addition, flow cytometry showed that 87% of the LAD2 human MC line and 98% of primary cultured human MC contained intracellular DP2. However, we could not detect surface expression of DP2 on human MC by single cell analysis using imaging flow cytometry. Blocking of endogenous PGD2 production with aspirin did not induce surface expression of DP2 in human MC. Two DP2 selective agonists, DK-PGD₂ and 15R-15-methyl PGD₂ induced dose-dependent intracellular calcium mobilization that was abrogated by pertussis toxin, but not by three DP2 selective antagonists. MC mediator release including degranulation was not affected by DP2 selective agonists. Thus, human MC express DP2 intracellularly rather than on their surface, and the function of DP2 in human MC is different than in other immune cells such as Th2 cells, eosinophils and basophils where it is expressed on the cell surface and induces Th2 cytokine and/or granule associated mediator release. Further studies to elucidate the role of intracellular DP2 in human MC may expand our understanding of this molecule and provide novel therapeutic opportunities.

Topics: Aspirin; Calcium; Cell Degranulation; Cell Line; Cytosol; Gene Expression; Humans; Ion Transport; K562 Cells; Leukocytes, Mononuclear; Mast Cells; Nasal Polyps; Pertussis Toxin; Primary Cell Culture; Prostaglandin D2; Receptors, Immunologic; Receptors, Prostaglandin; RNA, Messenger

Mast cells release mediators upon stimulation that contribute to the pathogenesis of chronic airway disease, including the recruitment and activation of Th2 lymphocytes. The objective was to determine the involvement of prostaglandin D(2) (PGD(2)) and its receptors in the chemotaxis of Th2 cells, using nasal polyp tissue.. Tissue explants from ten patients with nasal polyposis were incubated with RPMI alone or RPMI containing IgE/anti-IgE for 30 min. Some samples were treated with diclofenac to inhibit the production of PGD(2). Supernatants were assayed for PGD(2) content and for their ability to promote human Th2 cell chemotaxis in the presence and absence of a CRTH2 antagonist. Transcript levels of D protanoid receptor type 1 (DP(1)), chemoattractant receptor-homologous receptor expressed on Th2 cells (CRTH2) and PGD(2) synthase were analysed by real time PCR.. Increased release of PGD(2) by nasal polyp tissue treated with IgE/anti-IgE was significantly inhibited by preincubation of the tissue with diclofenac. Transcript levels of PGD(2) synthase, DP(1) and CRTH2 receptors increased after stimulation with IgE/anti-IgE. Supernatants from IgE/anti-IgE-stimulated nasal polyp tissue caused significantly increased chemotaxis of Th2 cells. The levels of PGD(2) produced and the degree of Th2 cell chemotaxis were highly correlated. Diclofenac inhibited the production of Th2 cell chemotactic activity, and the chemotactic effect of the supernatant on Th2 cells was inhibited by the CRTH2 antagonist ramatroban.. These data suggest that in immunologically activated nasal polyp tissue, PGD(2) produced by mast cells promotes the migration of Th2 cells through a CRTH2 dependent mechanism.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Antibodies, Anti-Idiotypic; Carbazoles; Chemotaxis, Leukocyte; Diclofenac; Humans; Immunoglobulin E; Lymphocyte Activation; Mast Cells; Nasal Polyps; Platelet Aggregation Inhibitors; Prostaglandin D2; Receptors, Immunologic; Receptors, Prostaglandin; Sulfonamides; Th2 Cells

Prostaglandin D(2) (PGD(2)) participates in airway inflammation. We reported that levels of hematopoietic-type PGD(2) synthase (h-PGDS) in sinonasal tissues may play an important role in the pathophysiology of chronic rhinosinusitis (CRS). Two PGD(2) receptors have been isolated, DP and CRTH2, but whether they participate in CRS remains unclear. We sought to determine the expression and characterization of DP and CRTH2 in CRS.. Expression of DP and CRTH2 in nasal polyps (NP) and uncinate process mucosae (UPM) was examined by in situ hybridization and immunohistochemistry and evaluated by real-time quantitative PCR. h-PGDS, IL-5, eotaxin and RANTES expression was also determined. In addition, the effect of PGD(2) on the expression of both receptors in UPM was assessed.. DP was widely expressed, not only in infiltrating inflammatory cells but also in constitutive cells such as vascular endothelial cells and ciliated columnar epithelia. CRTH2 was selectively expressed in inflammatory cells and some glands. Significantly greater levels of DP mRNA and conversely decreased levels of CRTH2 mRNA were observed in NP compared with UPM. DP and CRTH2 mRNA levels were not only positively and inversely correlated with levels of h-PGDS but also with eotaxin, respectively. Furthermore, addition of PGD(2) significantly increased DP expression and conversely reduced CRTH2 expression in UPM.. These results suggest that distinct expression of DP and CRTH2 is associated with the pathophysiology of CRS, including NP formation, and the expression of these receptors may be regulated by h-PGDS and PGD(2).

Topics: Adolescent; Adult; Aged; Chronic Disease; Eosinophils; Female; Gene Expression Regulation; Humans; Inflammation; Intramolecular Oxidoreductases; Lipocalins; Male; Middle Aged; Nasal Mucosa; Nasal Polyps; Prostaglandin D2; Receptors, Immunologic; Receptors, Prostaglandin; Rhinitis, Allergic, Perennial; RNA, Messenger; Sinusitis; Young Adult

The prevalence of patients with chronic rhinosinusitis (CRS) refractory to traditional therapy appears to be on the increase. In these cases, CRS tends to be associated with bronchial asthma (BA), especially, aspirin-intolerant asthma (AIA). On the other hand, arachidonic acid metabolites have been extensively investigated in the pathogenesis of BA. We sought to assess the role of prostaglandin D(2) (PGD(2)) and prostaglandin E(2) (PGE(2)) in the recalcitrant pathophysiology of CRS.. Samples were prepared from the nasal polyps and mucosa of 40 patients undergoing endoscopic sinus surgery (ESS) at our hospital. The nasal polyp specimens obtained from the patients with CRS were divided into three groups, as follows: the CRS-AIA group, consisting of specimens obtained from patients with CRS complicated by AIA, the CRS-ATA group, consisting of specimens obtained from patients with CRS associated with aspirin-tolerant asthma (ATA), and the CRS-NA group, consisting of specimens obtained from CRS patients without BA. PGD(2) and PGE(2) were extracted from the specimens and quantified.. The concentrations of PGD(2) were significantly higher in the nasal polyps of the CRS-ATA group. The concentrations of PGE(2) were lowest in the nasal polyps of the CRS-AIA group. The PGD(2)/PGE(2) ratio was highest in the CRS-AIA group.. It has previously been reported that CRS complicated by AIA is most likely to be characterized by repeated remissions and relapses, and is thus the most intractable. We may therefore say that the PGD(2)/PGE(2) ratio reflects the intractable nature of CRS.

Topics: Adult; Aged; Aspirin; Asthma; Cell Extracts; Chronic Disease; Dinoprostone; Drug Hypersensitivity; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Middle Aged; Nasal Polyps; Paranasal Sinuses; Prostaglandin D2; Rhinitis; Sinusitis

The mechanism of aspirin (acetylsalicylic acid [ASA]) sensitivity associated with severe asthma and chronic rhinosinusitis with nasal polyps ("aspirin triad") has been attributed to arachidonic metabolism alternations, although the putative biochemical defects have not been elucidated. The aim of this study was assessment of the hypothesis that local production of eicosanoids in the respiratory epithelium in patients with ASA-sensitive asthma/rhinosinusitis (ASARS) differs from that of ASA-tolerant patients with rhinosinusitis (ATRS). Nasal polyps were obtained from 10 patients with ASARS and 15 with ATRS during routine polypectomies, and epithelial cells (ECs) were cultured on bovine collagen type I matrix (Vitrogen 100), in medium supplemented with growth factors. The generation of eicosanoids in supernatants of confluent ECs (6 to 8 d of culture; purity > 98%) was quantified by immunoassays. Unstimulated ECs from ASARS patients generated significantly less prostaglandin E(2)(PGE(2)) compared with ATRS (0.8 +/- 0.3 versus 2. 4 +/- 0.5 ng/microg double-stranded deoxyribonucleic acid [dsDNA], respectively), although a similar relative increase in response to calcium ionophore and inhibition with ASA was observed in both groups. Basal levels of 15-hydroxyeicosatetraenoic acid (15-HETE) were not different between groups, and calcium ionophore enhanced its production to a similar extent. However, cells incubation with 200 microM ASA for 60 min resulted in a significant increase (mean +359%) in 15-HETE generation only in ASARS patients, whereas no effect of ASA on 15-HETE generation in ATRS patients was observed. PGF(2alpha) generation was similar in both groups, and no significant generation of PGD(2) or leukotriene C(4) (LTC(4)) was observed in epithelial cell cultures from either group. Our results indicate that nasal polyps ECs from ASA-sensitive patients have significant abnormality in basal and ASA-induced generation of eicosanoids which may be causally related to the mechanism of ASA sensitivity.

Topics: Adult; Aged; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Aspirin; Asthma; Cattle; Cells, Cultured; Dinoprostone; Drug Hypersensitivity; Female; Humans; Hydroxyeicosatetraenoic Acids; Male; Middle Aged; Nasal Polyps; Prostaglandin D2; Respiratory Mucosa

Inhaled furosemide protects asthmatic subjects against bronchial obstruction caused by indirect provocants. We have attempted to correlate the protective effect of furosemide with its ability to alter prostaglandin (PG) synthesis by the airway epithelium. Human epithelial cells from nasal polyps and bronchi were cultured in DME-Ham's F12 medium with 10% fetal calf serum. Confluent cells (days 6 through 8) were incubated for 30 min in fresh medium, and the PGs in the supernatant were measured by radioimmunoassay. Spontaneous output (ng.ml-1.mg-1 cell protein) was as follows (mean +/- SEM): PGE2 = 7.74 +/- 2.10 (n = 12), PGF2 alpha = 1.66 +/- 0.12 (n = 15), 6-keto-PGF1 alpha = 4.32 +/- 1.37 (n = 11), PGD2 = 0.73 +/- 0.16 (n = 11) for bronchial cells and PGE2 = 7.24 +/- 0.80 (n = 32), PGF2 alpha = 1.38 +/- 0.12 (n = 17), 6-keto-PGF1 alpha = 6.79 +/- 2.50 (n = 15), PGD2 = 0.42 +/- 0.07 (n = 17) for nasal cells. Incubation with arachidonic acid (25 micrograms/ml) for 30 min significantly increased the amounts of the four PGs. Incubation with furosemide (10(-4) M) for 30 min caused a marked reduction in both basal and arachidonic acid-stimulated production of PGE2 and PGF2 alpha but did not reduce production of 6-keto-PGF1 alpha and PGD2. Incubation with bumetanide (10(-4) M) for 30 min did not modify the PGE2 synthesis by nasal epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 6-Ketoprostaglandin F1 alpha; Arachidonic Acid; Bronchi; Bumetanide; Cells, Cultured; Dinoprost; Dinoprostone; Epithelial Cells; Epithelium; Furosemide; Humans; Nasal Mucosa; Nasal Polyps; Prostaglandin D2; Prostaglandins; Tumor Cells, Cultured