Gut microbiota and Hashimoto’s thyroiditis
About two third of the human microbial commensal community, namely the gut microbiota, is hosted by the gastrointestinal tract which represents the largest interface of the organism to the external environment. This microbial community co-evolved in a symbiotic relationship with the human beings. Growing evidence support the notion that the microbiota plays a significant role in maintaining nutritional, metabolic and immunologic homeostasis in the host. Microbiota, beside the expected role in maintaining gastrointestinal homeostasis also exerts metabolic functions in nutrients digestion and absorption, detoxification and vitamins’ synthesis. Intestinal microbiota is also key in the correct development of the lymphoid system, 70% of which resides at the intestinal level. Available studies, both in murine models and humans, have shown an altered ratio between the different phyla, which characterize a” normal” gut microbiota, in a number of different disorders including obesity, to which a significant part of the studies on intestinal microbiota has been addressed so far. These variations in gut microbiota composition, known as dysbiosis, has been also described in patients bearing intestinal autoimmune diseases as well as type 1 diabetes mellitus, systemic sclerosis and systemic lupus erythematosus. Being Hashimoto’s thyroiditis the most frequent autoimmune disorder worldwide, the analysis of the reciprocal influence with intestinal microbiota gained interest. The whole thyroid peripheral homeostasis may be sensitive to microbiota changes but there is also evidence that the genesis and progression of autoimmune thyroid disorders may be significantly affected from a changing intestinal microbial composition or even from overt dysbiosis. In this brief review, we focused on the main features which characterize the reciprocal influence between microbiota and thyroid autoimmunity described in the most recent literature.
KeywordsMicrobiota Dysbiosis Thyroid autoimmunity Hashimoto’s thyroiditis Probiotic
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
- 18.Graessler J, Qin Y, Zhong H, Zhang J, Licinio J, Wong ML, et al. Metagenomic sequencing of the human gut microbiome before and after bariatric surgery in obese patients with type 2 diabetes: correlation with inflammatory and metabolic parameters. Pharmacogenomics J. 2013;13:514–22.CrossRefGoogle Scholar
- 58.Kristensen B. Regulatory B and T cell responses in patients with autoimmune thyroid disease and healthy controls. Dan Med J. 2016;63 pii: B5177.Google Scholar
- 75.Sohail MU, Ijaz A, Yousaf MS, Ashraf K, Zaneb H, Aleem M, et al. Alleviation of cyclic heat stress in broilers by dietary supplementation of mannan-oligosaccharide and Lactobacillus-based probiotic: dynamics of cortisol, thyroid hormones, cholesterol, C-reactive protein, and humoral immunity. Poult Sci. 2010;89:1934–8.CrossRefGoogle Scholar
- 76.Chotinsky D, Mihaylov R. Effect of probiotics and Avotan on the level of thyroid hormones in the blood plasma of broiler chickens. Bulg J Agric Sci. 2013;19:817–21.Google Scholar
- 77.Varian BJ, Poutahidis T, Levkovich T, Ibrahim YM, Lakritz JR, Chatzigiagkos A, et al. Beneficial bacteria stimulate youthful thyroid gland activity. J Obes Weight Loss Ther. 2014;4:220.Google Scholar
- 85.Penhale WJ, Young PR. The influence of the normal microbial flora on the susceptibility of rats to experimental autoimmune thyroiditis. Clin Exp Immunol. 1988;7:288–92.Google Scholar