Effect of fucoidan on gut microbiota and its clinical efficacy in Helicobacter pylori eradication: A randomized controlled trial

OBJECTIVE

To assess the clinical efficacy of fucoidan-assisted standard quadruple therapy (SQT) in Helicobacter pylori (H. pylori) eradication and the improvement of gut microbiota.

METHODS

An open-label randomized controlled trial was conducted at the Affiliated Hospital of Qingdao University in Shandong Province, China. Ninety patients who tested positive for H. pylori were randomized to the standard quadruple therapy (SQT) group (SQ), SQT + fucoidan combination group (SF), and fucoidan + sequential SQT group (FS), respectively. Stool samples were collected for gut microbiota composition at baseline and after treatment.

RESULTS

After H. pylori eradication, the relative abundances of most conditional pathogens in the SQ decreased, while those of several beneficial bacteria increased or decreased (P < 0.05). In FS, the abundances of most beneficial bacteria increased gradually from baseline to week 12, while those of the conditional pathogens decreased (P < 0.05). The abundance of Bifidobacterium had a decreasing trend in SQ, but remained unchanged in SF and increased in FS (P < 0.05). The abundances of most beneficial bacteria were significantly higher in FS than in SQ and SF (P < 0.05). Addition of fucoidan enhanced symptom improvement during H. pylori eradication compared with SQT alone.

CONCLUSIONS

Fucoidan considerably improved gut dysbiosis during SQT for H. pylori eradication. Gut microbiota can be maintained by the addition of fucoidan before eradication therapy with SQT rather than by concomitant addition with therapy. Fucoidan-assisted SQT could relieve gastrointestinal symptoms during H. pylori eradication.

Transcriptome sequencing of Saccharina japonica sporophytes during whole developmental periods reveals regulatory networks underlying alginate and mannitol biosynthesis

BACKGROUND

Alginate is an important cell wall component and mannitol is a soluble storage carbon substance in the brown seaweed Saccharina japonica. Their contents vary with kelp developmental periods and harvesting time. Alginate and mannitol regulatory networks and molecular mechanisms are largely unknown.

RESULTS

With WGCNA and trend analysis of 20,940 known genes and 4264 new genes produced from transcriptome sequencing of 30 kelp samples from different stages and tissues, we deduced that ribosomal proteins, light harvesting complex proteins and "imm upregulated 3" gene family are closely associated with the meristematic growth and kelp maturity. Moreover, 134 and 6 genes directly involved in the alginate and mannitol metabolism were identified, respectively. Mannose-6-phosphate isomerase (MPI2), phosphomannomutase (PMM1), GDP-mannose 6-dehydrogenase (GMD3) and mannuronate C5-epimerase (MC5E70 and MC5E122) are closely related with the high content of alginate in the distal blade. Mannitol accumulation in the basal blade might be ascribed to high expression of mannitol-1-phosphate dehydrogenase (M1PDH1) and mannitol-1-phosphatase (M1Pase) (in biosynthesis direction) and low expression of mannitol-2-dehydrogenase (M2DH) and Fructokinase (FK) (in degradation direction). Oxidative phosphorylation and photosynthesis provide ATP and NADH for mannitol metabolism whereas glycosylated cycle and tricarboxylic acid (TCA) cycle produce GTP for alginate biosynthesis. RNA/protein synthesis and transportation might affect alginate complex polymerization and secretion processes. Cryptochrome (CRY-DASH), xanthophyll cycle, photosynthesis and carbon fixation influence the production of intermediate metabolite of fructose-6-phosphate, contributing to high content of mannitol in the basal blade.

CONCLUSIONS

The network of co-responsive DNA synthesis, repair and proteolysis are presumed to be involved in alginate polymerization and secretion, while upstream light-responsive reactions are important for mannitol accumulation in meristem of kelp. Our transcriptome analysis provides new insights into the transcriptional regulatory networks underlying the biosynthesis of alginate and mannitol during S. japonica developments.