Influence of Chemotherapy on the Microbiome and Immunological Functioning of the Gut

Abstract

In addition to the billions of human cells comprising the human body, parts of our bodies are actually home to large communities of microorganisms, known as microbiomes. The organisms present in these communities include bacteria, yeasts, protozoa, viruses and more. Unique microbiomes colonize the skin, the oral cavity, the gastrointestinal tract, and the genitourinary tract. The microorganisms usually are commensal or mutualistic bacteria that maintain homeostasis in our organ systems, prevent infection, and aid in necessary biological functions within the body - such as digestion.¶ The gut microbiome is influenced by many factors including: age, diet, lifestyle, environment, and intake of medications. Disturbances in the community of microorganisms within the gut (defined herein as referring to the intestines) has ramifications throughout the body and involves multiple other organ systems, including the digestive system, nervous system, and immune system. Chronic diseases may cause or develop due to microbial dysbiosis originating in the gut.¶ Chemotherapeutics are known to induce microbial gut dysbiosis and cause serious side effects, including intestinal mucositis–a painful, ulcerative inflammation of the intestinal epithelium. As a summer research intern in the laboratory of Dr. Nissan Yissachar, Bar Ilan University, I was involved in isolating bacteria from fecal samples of breast cancer patients, before and after chemotherapy treatment. These isolated bacteria will be used in an transepithelial electrical resistance (TEER) assay, to determine their influence on the epithelial lining of the gut. The goal is to identify those bacteria that colonize the gut subsequent to chemotherapy and that strengthen the epithelial lining of the gut. The overall intent of this research is to utilize these bacteria to prevent dysbiosis-induced side effects, includin.g chemotherapy-induced mucositis. The laboratory requested that, when authoring this Senior Project, I limit my description of the research and its findings