Role of Acidic Mammalian Chitinase and Chitotriosidase in Nasal Polyps
Department of Otorhinolaryngology-Head and Neck Surgery, Inje University College of Medicine, Busan Paik Hospital, Busan, Korea. Otolaryngology Head and Neck Surgery
(Impact Factor: 2.02).
10/2009; 141(4):462-6. DOI: 10.1016/j.otohns.2009.06.013
Chitin is a recognition element for tissue infiltration by innate cells implicated in allergy and helminth immunity, and this process can be negatively regulated by vertebrate chitinases. Acidic mammalian chitinase (AMCase) and chitotriosidase (ChT) have chitinolytic activity, but little is known about their roles in nasal polyps.
A prospective controlled study.
A tertiary referral center.
Nineteen subjects with nasal polyps and 12 subjects with deviated nasal septums were recruited to obtain inferior turbinate mucosa samples. The expression levels of AMCase and ChT were compared in nasal polyp and inferior turbinate tissue samples. The tissue samples were analyzed by reverse transcription-polymerase chain reaction, Western blotting, and immunohistochemical staining.
AMCase and ChT were detected in all nasal polyps and inferior turbinate tissues. AMCase and ChT messenger RNA and protein expression were significantly higher in nasal polyps than in inferior turbinate tissues. In nasal polyps, AMCase-positive and ChT-positive cells were detected in the epithelium, inflammatory cells, and submucosal gland.
AMCase and ChT may be important mediators in the pathogenesis of nasal polyps. Nasal polyps appear to have elevated levels of chitinases, and the presence or growth of chitin-containing pathogens might enhance chitinase expression, resulting in nasal polyp formation and growth in susceptible individuals.
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ABSTRACT: Chitin is a recognition element for tissue infiltration by innate cells implicated in allergy and immunity. This process can be negatively regulated by vertebrate chitinases. Both acidic mammalian chitinase (AMCase) and chitotriosidase (ChT) have chitinolytic activity. This study aimed to determine the activities of AMCase and ChT in nasal polyps (NPs), as well as their in situ localization in NP tissue.
AMCase and ChT activities in NPs were compared with those in inferior turbinate tissue samples. Tissue samples were measured for AMCase and ChT activities at a range of pHs using the fluorogenic substrate 4-methylumbelliferyl-beta-d-N,N',N''-triacetyl-chitotriose. Double immunofluorescent staining for the localization of both AMCase and ChT was performed using NP cryosections.
Both AMCase and ChT displayed markedly increased chitinolytic activity in all NPs, compared with inferior turbinate tissues. Double immunofluorescent staining revealed that CD68 highlighted monocytes in the submucosa of NP and these cells disclosed coexpression of AMCase and ChT. CD31 detected capillary endothelial cells, but did not express any AMCase and ChT.
The increased chitinolytic activities of AMCase and ChT in NPs may be important in NP pathogenesis, suggesting that inhibition of chitinolytic activity may be a novel therapeutic strategy for the treatment of NPs.
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ABSTRACT: Acidic mammalian chitinase (AMCase) has been found to play an important role in allergy and asthma. Chronic rhinosinusitis with nasal polyps (CRSwNPs) is chronic inflammation with eosinophilic infiltration, which is similar to asthmatic inflammation. The role of AMCase in CRSwNPs has been less studied. Eotaxin-3 is a potent eosinophil attractant and can induce eosinophil recruitment and activation in the airways of asthmatics. The expression and role of eotaxin-3 messenger ribonucleic acid (mRNA) and its relationship to AMCase in CRSwNPs have not been studied previously.
Twenty-three subjects with nasal polyps and nine subjects with nasal septum deviation were included in the study. The polyps and inferior turbinate mucosa were obtained as the tissue samples. Real-time reverse transcriptase-polymerase chain reaction was used to analyze and compare the expression levels of AMCase and eotaxin-3 in nasal polyps and inferior turbinate tissues (ITTs).
AMCase and eotaxin-3 were detected in all nasal polyps and ITTs. The expression ratio of AMCase mRNA was 123.90 ± 30.60 in nasal polyps and 2.38 ± 0.41 in ITTs. The expression ratio of eotaxin-3 mRNA was 43.58 ± 15.15 and 0.84 ± 0.30, respectively. The expression of AMCase and eotaxin-3 mRNA was significantly higher in nasal polyps than in ITTs (p < .01).
Our results reveal that AMCase and eotaxin-3 may be important mediators in the pathogenesis of nasal polyps. The increased AMCase and eotaxin-3 might lead to nasal polyp formation and growth. Future studies are needed to determine the potential of AMCase and eotaxin-3 as therapeutic targets in CRSwNPs.
Available from: Mingzhu Jin
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ABSTRACT: Chronic rhinosinusitis with nasal polyps (CRSwNP) is connected to a chronic inflammatory process with the activation of different immune components. Eotaxin-3, acidic mammalian chitinase (AMCase), and interleukin (IL)–13 as focal immune factors have been detected in CRSwNP, but their importance and relationship are still being investigated. This study aims to detect the expression of AMCase, IL-13, and eotaxin-3 in the mRNA level and investigate their roles and relationships in CRSwNP. Twenty-four subjects with eosinophilic CRSwNP and 11 controls were included in the study. Tissues were obtained by endoscopic sinus surgery. Target genes were detected by real-time reverse transcription–polymerase chain reaction. AMCase, eotaxin-3, and IL-13 were detected in all CRSwNP and controls. The expression of AMCase, eotaxin-3, IL-13, and mRNA was significantly higher in patients with CRSwNP than in the control group. There was a significantly positive correlation not only between AMCase and eotaxin-3 but also between IL-13 and eotaxin-3 in CRSwNP. Increased AMCase, IL-13, and eotaxin-3 might lead to the Th2 inflammatory cascade reaction.
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