Probiotics as a Potential Alternative for Relieving Peripheral Neuropathies: a Case for Guillain-Barré Syndrome

Trillions of microorganisms form the “natural flora” of the human body. These microorganisms outnumber the host cells 10 to 1, essentially making humans a microbial ecosystem of sorts. Before the advent of the high-throughput sequencing technologies such elusive microorganisms were uncultivable and could not be studied using traditional microbiological techniques. However, since the past decade, with the establishment of the Human Microbiome Project reference database in 2012, research in this area has grown logarithmically (Grogan, 2015). The human microbiota is introduced from mother to the fetus and even infants, and remains with the growing individual for the rest of his/her life, being effected by and also affecting the individual's lifestyle, food habits, and metabolism. Friendly microbes have been shown to protect from several diseases and a dysbiosis in the microbiota has been linked to infections by pathogens, autoimmunity and lifestyle disorders. The establishment of the brain-gut axis (reviewed in Carabotti et al., 2015) in the past few years has even shown that gut microbiota and brain affect each other (Carabotti et al., 2015). A very recent study established the missing link between the central nervous system (CNS) and the immune system i.e., the CNS lymphatic vessels, thus completing the microbiota-neuronal-immune system triangle (Louveau et al., 2015). Even stress, and behavioral changes can result in an altered microbiota and vice–versa (Schmidt, 2015). This has brought microbiologists and neuroscientists together to look into the probable mechanisms in which dysbiosis of gut microbiota may affect development of neurodegenerative diseases and even neuronal autoimmunity. Autoimmune diseases of both the central and the peripheral nervous system (PNS) have been linked to microbiota, although the extent to which the link has been established is very different. While some like multiple sclerosis (MS) has working mice-models, others like Guillain–Barré syndrome (GBS), a rare autoimmune disorder of the PNS has no defined models, although experimental autoimmune neuritis (EAN) may be used to study some aspects of GBS, especially macrophage mediated demyelination (Kieseier et al., 2012). Even so, we have been warned against the fallacies of studying such models in isolation, as there is no strict one model-one disorder kind of relationship between human autoimmunity and mouse/rat model (Gold et al., 2000). Since probiotics have been found to be useful in the treatment of autoimmune diseases like Inflammatory Bowel Disease (IBD) (Sheil et al., 2007), type1 diabetes (Calcinaro et al., 2005) and even extra-intestinal neuronal and systemic-autoimmune disorders like MS (Lavasani et al., 2010) and systemic lupus erythematosus (SLE) (Manirarora et al., 2008; Alard et al., 2009), testing the efficacy of probiotics in the treatment of GBS might offer a less invasive and more acceptable and economical treatment alternative.?