Alteration in gut microbial characteristics of patients with acromegaly.

Purpose: Studies on intestinal microbiota in acromegaly are scant. This study aimed to characterize the gut microbiome in patients with acromegaly.

Method: Stool samples were collected from 11 patients newly diagnosed with acromegaly and 12 healthy controls matched for body mass index (BMI) and age after three days on a standard diet. Clinical and gut microbial composition assessments were performed for the two participant groups using 16S rRNA gene amplicon sequencing.

Results: There was no difference in the alpha diversity of the microbiota between the samples from patients with acromegaly and those from the healthy controls. Based on beta diversity measurements, differences in microbial community structures were found to be significant only when compared using the Jaccard similarity index. The corresponding Firmicutes/Bacteroidota ratio tended to be higher in individuals with acromegaly than in healthy controls. The mean relative abundance of Actinobacteriota was 2.3 times higher in the acromegaly patient group than in the control group. Eggerthellaceae, Christensenellaceae, and Bacteroidaceae were among the significantly abundant bacterial families in the samples from the acromegaly patient group, while Butyricicoccaceae and Tannerellaceae were decreased. At the level of the genus, the most discriminative features were the abundance of Prevotella 7, Bacteroides, Senegalimassilia, Enterohabdus, the Family XIII AD3011 group, Howardella, and Hungatella in the samples from the acromegaly patient group. In contrast, the Butyrivibrio and the Eubacterium eligens group were the most discriminative genera for the healthy controls and were significantly less abundant in patients with acromegaly. While there were no significantly differentiated taxa between the diabetic and non-diabetic subgroups, Prevotella_7 was significantly enriched in the osteoarthritis (OA) subgroup. No significant association was found between individual genera and growth hormone (GH) levels and insulin-like growth factor-1 (IGF-1) levels as well as the upper limit of normal (ULN).

Conclusion: Although alpha and beta diversity were mainly similar between the two groups, significant differences were observed between the acromegaly group and the control group at the family and genus levels. These results suggest that the differences between the microbial communities in patients with acromegaly and those in healthy individuals consist primarily of compositional differences independent of abundance. Prospective studies are needed to further explore the clinical implications of gut microbiome dysbiosis in patients with acromegaly.