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Desenvolvimento de vacinas contra Helicobacter pylori
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Orientador(es)
Resumo(s)
A Helicobacter pylori é uma bactéria gram-negativa que coloniza o estômago de praticamente metade da população mundial, estando associada a um risco aumentado de desenvolver uma diversidade de manifestações clínicas tanto gástricas como extragástricas. As mais comuns são as complicações gástricas através do desenvolvimento de gastrites, úlceras pépticas, linfomas associados às mucosas e adenocarcinomas gástricos.
Foi classificada como cancerígeno do grupo 1 pela Organização Mundial de Saúde, por ser um dos cancros mais prevalentes no mundo e responsável por um número elevado de mortes associadas.
A infeção é adquirida na infância e se não for tratada permanece no organismo humano durante toda a vida. Encontra-se mais intensificada nos países em desenvolvimento e o principal fator de risco associado à infeção é o baixo nível socioeconómico principalmente na infância. A sua transmissão ocorre sobretudo via interpessoal, nomeadamente no seio familiar.
A terapêutica atualmente considerada para combater a infeção é a combinação de antibióticos com inibidores da bomba de protões, porém esta terapêutica não está a alcançar o sucesso que se desejaria. As altas taxas de resistências aos antibióticos, as posologias complexas, o elevado custo em países em desenvolvimento, a não adesão à terapêutica são
alguns problemas emergentes que a terepêutica atual está a enfrentar.
O desenvolvimento de uma vacina torna-se assim uma alternativa extremamente promissora e diversas estratégias têm sido desenvolvidas tanto na descoberta de uma vacina profilática, como numa vacina terapêutica, ambas com diferentes públicos-alvo.
No entanto, esta tarefa está a revelar-se bastante complexa, porque embora muito conhecimento já tenha sido acumulado, fatores chave que podem revolucionar o sucesso da vacina ainda estão em falta. A inexistência de ensaios clínicos intensivos e conclusivos também está a dificultar o processo. Até a data não existe nenhuma vacina comercializada, e poucas são as que se encontram em ensaios clínicos humanos, o que prediz que muito trabalho ainda tem que se percorrer para encontrar uma vacina que consiga controlar a infeção por H. pylori.
Helicobacter pylori is a gram negative bacterium that colonizes the stomach of almost half of the world’s population, being associated with an increased risk of developing a diversity of clinical manifestations gastrics and extragastrics. The most common are upper gastrointestinal disorders such as chronic gastritis, peptic ulcer disease, gastric mucosaassociated lymphoid tissue lymphoma, and gastric cancer. It was designated as class I carcinogen by the World Health Organization, for being one of the most prevalent cancers in the world and is responsible for a high number of deaths. The infection is normally acquired in childhood and if not treated remains in human organism for life. It is more intensified in developing countries and the main risk factor associated with the infection is low socioeconomic status, especially in childhood. The transmission occurs mainly through interpersonal relationships, especially in household. The therapy currently considered to treat the infection is the combination of antibiotics with proton pump inhibitors, but this therapy is not achieving the desired success. High rates of antibiotic resistance, complex dosages, high cost in developing countries, non-adherence to therapy are some emerging problems that this therapeutic is facing. The development of a vaccine becomes an extremely promising alternative and several strategies have been developed in the discovery of a prophylactic and therapeutic vaccine, with different target audiences. However, this task is proving to be quite complex, because although a lot of knowledge has already accumulated, key factors that can revolutionize the vaccine’s success are still missing. The realization of intensive and conclusive clinical trials is also complicating the process. To date, there is no commercialized vaccine, and few human clinical trials are in course, which predicts that much work still needs to be done to find a vaccine that can control H. pylori infection.
Helicobacter pylori is a gram negative bacterium that colonizes the stomach of almost half of the world’s population, being associated with an increased risk of developing a diversity of clinical manifestations gastrics and extragastrics. The most common are upper gastrointestinal disorders such as chronic gastritis, peptic ulcer disease, gastric mucosaassociated lymphoid tissue lymphoma, and gastric cancer. It was designated as class I carcinogen by the World Health Organization, for being one of the most prevalent cancers in the world and is responsible for a high number of deaths. The infection is normally acquired in childhood and if not treated remains in human organism for life. It is more intensified in developing countries and the main risk factor associated with the infection is low socioeconomic status, especially in childhood. The transmission occurs mainly through interpersonal relationships, especially in household. The therapy currently considered to treat the infection is the combination of antibiotics with proton pump inhibitors, but this therapy is not achieving the desired success. High rates of antibiotic resistance, complex dosages, high cost in developing countries, non-adherence to therapy are some emerging problems that this therapeutic is facing. The development of a vaccine becomes an extremely promising alternative and several strategies have been developed in the discovery of a prophylactic and therapeutic vaccine, with different target audiences. However, this task is proving to be quite complex, because although a lot of knowledge has already accumulated, key factors that can revolutionize the vaccine’s success are still missing. The realization of intensive and conclusive clinical trials is also complicating the process. To date, there is no commercialized vaccine, and few human clinical trials are in course, which predicts that much work still needs to be done to find a vaccine that can control H. pylori infection.
Descrição
Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, 2022, Universidade de Lisboa, Faculdade de Farmácia.
Palavras-chave
Helicobacter pylori Vacina Cancro gástrico Antigénios Ensaios clínicos Mestrado integrado - 2022