Introduction
Interaction between gut microbiota and thyroid gland: gut-thyroid axis
Dysbiosis in HT
Cohort | Country | Method | Increase | Decrease | References |
---|---|---|---|---|---|
HT versus healthy individuals | Brazil | Real-time PCR | Bacteroides | Bifidobacterium | [24] |
HT versus healthy individuals | China | 16S rRNA gene sequencing | Blautia Roseburia Ruminococcus Romboutsia Dorea Fusicatenibacter Eubacterium | Faecalibacterium Bacteroides Prevotella_9 Lachnoclostridium | [35] |
HT versus healthy individuals | China | PCR-DGGE, Real-time PCR, 16S rRNA gene sequencing | Proteobacteria Cyanobacteria Actinobacteria Enterobacteriaceae Alcaligenaceae | Firmicutes Bacteroidetes Veillonelliaceae Prevotellaceae Dialister Bifidobacterium Lactobacillus | [36] |
HT with ab/normal thyroid function versus healthy individuals | China | 16S rRNA gene sequencing | Akkermansia Lachnospiraceae Bifidobacterium Shuttleworthia Clostriworthdia | Lachnoclostridium Bilophila | [37] |
HT with ab/normal thyroid function versus healthy individuals | China | 16S rRNA gene sequencing | Phascolarctobacterium Lachnospiraceae_ Lactonifactor Alistipes Subdoligranulum | – | [41] |
Primary hypothyroidism versus healthy individuals | China | 16S rRNA gene sequencing | Neisseria Rheinheimera | Veillonella Paraprevotella | [23] |
HT versus GD and healthy individuals | Spanish | 16S rRNA gene sequencing | Victivallaceae Streptococcus Rikenellaceae | Faecalibacterium | [38] |
Effect of microbiota on the immune system
Microbiota and innate immunity
Microbiota and adaptive immunity
Microbiota and thyroid autoimmunity
The intestinal barrier in HT
Microbiota and autophagy defect
Microbiota and metabolites regulate inflammation
Intestinal microbiota affects thyroid function
Effect of thyroid on the gastrointestinal tract
The relationship between HT and related digestive diseases
HT and celiac disease (CD)
HT and Hp infection gastritis
HT and autoimmune atrophic gastritis(AAG)
Potential therapeutic strategies by regulating the gut-thyroid axis
Intestinal non-absorbable antibiotics
Rebuild intestinal ecology
Dietary therapy and trace element intake
Biomarkers provide new targets
Source | Mechanism | Significance | References | |
---|---|---|---|---|
Zonulin/I-FABP/DAO | IECs | Adjust TJ | Reflect intestinal permeability | |
Claudin-2 | IECs | Regulate cell bypass permeability | Increased claudin-2 expression is associated with autophagy inhibition | |
NLRP1/ASC | TFCs | Mediates pyroptosis and cytokine (IL-1 β, IL-18) release to induce immune response | The mRNA level is correlated with the serum TPOAb and TgAb levels | [28] |
NLRP3 | TFCs | Mediates pyroptosis and cytokine (IL-1 β, IL-18) release to induce immune response | Increased expression in HT patients; Maintain intestinal microflora homeostasis | |
TMAO | Microbial metabolites | Enhance the activation and formation of NLRP3, ASC, IL-1b and caspase-1 | Promote inflammatory reaction | [111] |
SCFAs | Microbial metabolites | Inhibit HDAC; Reduce INF-γ; Regulate T cell polarization; Strengthen TJs with thyroid hormone | Affect immune regulation, Anti-inflammatory Maintain intestinal barrier | |
DCA | Microbial metabolites | Reduce bacterial overgrowth by inducing membrane damage | Signs of overgrowth of small intestinal bacteria | |
LPS | Microbial metabolites | Increasing the expression of Tg and NIS genes; TLR-4 mediates the downstream activation of NF-kB; Affects the activity of deiodinase | Sensitive index of bacterial translocation; Cause thyroid homeostasis disorder | |
H3K4me3 | Histone | Abnormal PTMP | Epigenetic marker | |
Cag-A | Helicobacter pylori | The nucleotide sequence of Cag-A positive Helicobacter pylori is similar to TPO sequence | Serum positive rate is related to AITD | [149] |