Changing Gut Microbiota Pattern through Antibiotics and Fecal Microbiota Transplantation - A New Approach in Treating Inflammatory Bowel Diseases
Crohn's Disease and Ulcerative Colitis: Inflammatory bowel diseases (IBD), such as Crohn's disease and ulcerative colitis, are characterized by chronic inflammation in the intestines that is not proportional to the presence of normal gut bacteria. These conditions are not autoimmune diseases. Although more than 160 genes associated with IBD development are known, genetics only explain about one-third of cases, with the environment accounting for the rest. Interestingly, almost a century ago, IBD cases were rare despite the presence of relevant genes. Various theories attempt to explain the environmental factors driving the dramatic rise in IBD prevalence in recent decades, but the gut microbiota pattern has a significant role in disease onset and exacerbation.
Normal Gut Microbiota: Our intestines normally harbor over ten times the number of bacteria as cells in our body. These bacteria maintain a delicate balance among themselves, as well as with our immune system, by releasing molecules that mediate interactions between cells and bacteria. In fact, the metabolic products of gut bacteria, constituting over 60% of dry stool weight, outweigh those of even our liver.
Inflammation in IBD: Chronic inflammation in IBD can arise from several factors, including alterations in the gut microbiota, increased permeability of the intestinal lining allowing bacteria to penetrate, or changes in the immune system's function. These changes might result from both genetic and environmental factors. Regardless of the cause, the body struggles to cope with bacterial infiltration, leading to a strong but inefficient immune response. Prolonged inflammation damages the intestinal lining, causing typical symptoms like diarrhea, abdominal pain, absorption issues, and persistent damage to the intestines.
Current Treatments: Drugs targeting inflammation, such as steroids, immunosuppressants, and biologics, have shown effectiveness in IBD treatment. However, these treatments often alleviate symptoms temporarily, similar to treating a grain of sand in the eye, where anti-inflammatory agents might relieve pain and redness but don't eliminate the cause. Microbiota studies demonstrate that the composition changes after IBD diagnosis and during active disease, indicating that microbial alterations contribute to disease progression.
Probiotics, Antibiotics, and Fecal Microbiota Transplantation (FMT): Recent research focuses on interventions that impact the gut microbiota, including probiotics, antibiotics, and fecal microbiota transplantation (FMT). While specific probiotic strains like E. coli Nissle and VSL#3 have shown mild efficacy in ulcerative colitis, antibiotics have demonstrated promise in both Crohn's and ulcerative colitis. A study of the antibiotic combination azathioprine and metronidazole, along with newer agents like vedolizumab, has shown positive outcomes.
FMT in IBD Treatment: The interest in fecal microbiota transplantation (FMT) has also been renewed, especially due to a study suggesting its effectiveness in Clostridium difficile infection. FMT involves transferring fecal matter from a healthy donor to a patient's intestines, aiming to restore a healthy gut microbiota. Although many anecdotal case descriptions exist, scientific evidence for FMT in IBD is still limited. There are cases of both success and failure, but the lack of standardized procedures, potential risks, and unknown long-term effects necessitate further research to draw definitive conclusions.
Considerations for FMT: FMT is currently considered for severe cases of IBD that haven't responded to standard treatments. Given its lack of significant adverse effects, it's theoretically logical to attempt FMT, as it aligns with the notion that disease arises from microbiota imbalance. However, the absence of standardized protocols, varying outcomes, and potential risks should be weighed when considering FMT as an intervention. Studies suggest that FMT can induce weight gain, mood changes, and other undefined effects. Also, there's a theoretical risk of transferring unknown conditions through FMT, which might make familial donors a preferred choice.
Conclusion: Considering the evolving understanding of gut microbiota's role in IBD, interventions like antibiotics and FMT hold promise for disease management. Yet, thorough research, standardized protocols, and long-term assessment are necessary before implementing these strategies widely. Given the complexity of IBD and the gut microbiome, future advancements will likely provide a clearer picture of their potential benefits and risks.