Extradigestive Manifestations of Helicobacter Pylori Infection â#x80;#x93; An Overview

Helicobacter pylori is an ancient microorganism that co-evolved with humans for many years and typically colonizes the human stomach and is being recognized as the most common infectious pathogen of the gastroduodenal tract. Some years after bacterium isolation, epidemiological studies have revealed a correlation between its infection and some diseases localized outside the stomach, such as hematological, hepatobiliary, pancreatic, cardiovascular, neurological, dermatological and respiratory diseases. Different mechanisms of action have been proposed, ranging from the induction of a low-grade inflammatory state to the occurrence of molecular mimicry mechanisms. This book is an overview of contributors surrounding the association of H. pylori infection with extragastric diseases, based on evidence, bacterial-host interactions and mechanisms implicated in the pathogenesis of some of these disorders Helicobacter pylori (H. pylori) is well known as a group I human gastric cancer carcinogen by the International Agency for Research on Cancer. Although an exact causal relationship is unclear, H. pylori is expected to have been associated with non-digestive abnormal condition and/or diseases, such as metabolic syndrome, atherosclerosis and cardiovascular diseases, which have substantially lots of prior studies; adaptive immune response -related disorders, such as autoimmune thyroid diseases (ATDs), urticaria, atopy and asthma; and the other extra-digestive diseases, such as chronic obstructive pulmonary disease (COPD), migraine, anemia and hyperemesis gravidarum. This chapter overviews several groups of extra-digestive diseases by H. pylori infection and discusses the role of H. pylori in relation to the diseases in the viewpoint of causality