Helicobacter pylori binding microspheres to prevent gastric cancer

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1 Helicobacter pylori binding microspheres to prevent gastric cancer Inês C. Gonçalves 16 th April 2015 Encontros com a Inovação em Saúde

2 Helicobacter pylori infection World population 7 billion people 50% Wroblewski et al. Clin Microbiol Rev 2010 Infected with H. pylori Develop gastric cancer Have recomendation for H. pylori treatment H. pylori treatment is inneficient 1% 20% symptomatic Malfertheiner et al. Lancet % Vakil et al. Am J Gastroenterol ,5 billion people Wroblewski et al. Clin Microbiol Rev 2010; Peek et al J. Pathol million people 700 million people 140 million people

3 The technology Chitosan microspheres that, after oral administration, will adhere to gastric mucosa, bind H. pylori and eliminate it through the gastrointestinal tract. Patent WO A2

4 The biomaterial Chitosan NH 3 + NH 3 + Mucoadhesive properties Natural polymer Other sources: Source: Squid pen (Chitin)

5 Mean size ( m) Chitosan microspheres ph 7.4 ph 6.0 ph 4.0 ph 2.6 ph 1.2 ph7.4 ph6.0 ph4.0 ph2.6 ph1.2 * * Diameter of 170 µm Stable in gastric acidic ph I.C. Gonçalves*, et al. Acta Biomaterialia 9 (2013)

6 Chitosan microspheres 0,2mg Ch Mic MKN45 gastric cells Gastric retention time of 2h Not cytotoxic I.C. Gonçalves, et al. Acta Biomaterialia 9 (2013) M. Fernandes*, I.C. Gonçalves*, et al. Int. J. of Pharmaceutics 454 (2013)

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8 Chitosan microspheres adhesion to H. pylori J99 BabA+/SabA /Leb BabA+/SabA baba1a2 BabA-/SabA+ 097UK BabA-/SabA- ph 6.0 ph 2.6 I.C. Gonçalves, et al. Acta Biomaterialia 9 (2013)

9 Helicobacter pylori adhesion to gastric mucosa The adhesion of H. pylori to the gastric mucosa involves specific interaction between bacteria adhesins and glycosylated receptors of gastric mucins and gastric epithelial cells. SabA (sialic acid binding adhesin) binds to inflammationassociated sialyl-lewis a and silayl-lewis X structures [Mahdavi et al, 2002] Adapted from Magalhães A et al, 2010 BabA (blood group antigen binding adhesin) binds to H-type 1 and Lewis b structures expressed in normal gastric mucosa [Ilver et al, 1998]

10 GlyR-Ch Mic Ch Click Chemistry Ch_ Le b sle x WO A2 (PCT/GB2013/051181). MICROSPHERES. M. Cristina L. Martins et al.

11 H. pylori adhesion to GlyR Ch Mic Ch Ch_ Le b sle x + BabA+/SabA- H. pylori + BabA+/SabA- H. pylori + BabA+/SabA- H. pylori + BabA+/SabA- H. pylori WO A2 (PCT/GB2013/051181). MICROSPHERES. M. Cristina L. Martins et al.

12 17875/Leb adhesion to mice gastric mucosa [% in relation to the control] 17875/Leb adhesion to human gastric mucosa sections [% in relation to the control] In vitro gastric mucosa model Sections from paraffin embedded stomachs *** 46% *** 60% *** 43% Mic Ch Mic Ch_ Mic Le b Mic sle x 0 Mic Ch Mic Ch_ Mic Le b Mic sle x Welch - ANOVA: Tamhane s T2 post hoc test (***p<0.001; **p<0.01)

13 Ex vivo Ex vivo and in vivo mouse gastric mucosa model In vivo fresh stomachs * * 0,2 mg Ch Mic 1x/day for 15 days 0,4 mg Ch Mic 1x/day for 15 days 63% reduction of H. pylori infection One-way ANOVA with LSD post hoc (p*<0.05)

14 Conclusions Ch microspheres are stable in acidic ph (do not dissolve), are non-cytotoxic and are retained in mice stomachs for 2h. Ch microspheres are able to bind different H. pylori strains (unspecifically). Glycan-modified microspheres bind H. pylori specifically through carbohydrate-adhesin binding and remove H. pylori adhesion, competing with carbohydrates from the gastric mucosa. In this panorama, chitosan microspheres should be considered as alternative therapy for H. pylori infection treatment.

15 Advantages No problems associated with antibiotics use (bacterial resistance, side effects, ); Huge market as H. pylori infection treatment: All infected population (3.5 billion people) Patients who have recommendation for treatment (700 million) Patients that do not respond to antibiotherapy (140 million); Chitosan microspheres may be used as unspecific treatment, while glycan coated microspheres may provide a personalized treatment for specific bacterial strains. Could also be used as preventive treatment or in combination with other treatments, namely as local drug delivery system;

16 Acknowledgements Cristina Martins Ana Margarida Costa Ana Patrícia Henriques Inês Vigário Rodrigues Mariana Fernandes Zé Ricardo Oliveira Bernardo Antunes Vanessa Graça Catarina Seabra Frederico Nogueira Paula Parreira Celso Reis Ana Magalhães Joana Gomes Leonor David Patrícia Castro Fátima Carneiro José Manuel Lopes António Gouveia Paula Gomes Rui Fernandes Paula Sampaio Sofia Lamas Paulo Costa Thomas Bóren Eliette Touati Mário Barbosa Isabel Amaral Stefania Nardecchia Maria Oliveira Maria Lazaro João Cortez FCT: Glycobacter, Pyloricidal and SweetMic projects and Post-Doc grant ON2 for project Norte Feder-00005