Estudos clínicos da glicosamina

Mar. Drugs 2010, 8, 292-312; doi:10.3390/md8020292
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Marine Drugs
ISSN 1660-3397 www.mdpi.com/journal/marinedrugs Review

Chitins and Chitosans as Immunoadjuvants and Non-Allergenic Drug Carriers
Riccardo A. A. Muzzarelli Emeritus Professor, University of Ancona, Ancona, Italy; E-Mail: [e-mail]; Tel./Fax: [phone]; Mobile: [phone]; http://www.chitin.it/ Received: 27 January 2010 / Accepted: 20 February 2010 / Published: 21 February 2010

Abstract: Due to the fact that some individuals are allergic to crustaceans, the presumed relationship between allergy and the presence of chitin in crustaceans has been investigated. In vivo, chitin is part of complex structures with other organic and inorganic compounds: in arthropods chitin is covalently linked to proteins and tanned by quinones, in fungi it is covalently linked to glucans, while in bacteria chitin is diversely combined according to Gram(+/-) classification. On the other hand, isolated, purified chitin is a plain polysaccharide that, at the nano level, presents itself as a highly associated structure, recently refined in terms of regularity, nature of bonds, crystallinity degree and unusual colloidal behavior. Chitins and modified chitins exert a number of beneficial actions, i.e., (i) they stimulate macrophages by interacting with receptors on the macrophage surface that mediate the internalization of chitin particles to be degraded by lysozyme and N-acetyl-β-glucosaminidase (such as Nod-like, Toll-like, lectin, Dectin-1, leukotriene 134 and mannose receptors); (ii) the macrophages produce cytokines and other compounds that confer non-specific host resistance against bacterial and viral infections, and anti-tumor activity; (iii) chitin is a strong Th1 adjuvant that up-regulates Th1 immunity induced by heat-killed Mycobacterium bovis, while down- regulating Th2 immunity induced by mycobacterial protein; (iv) direct intranasal application of chitin microparticles into