Changes in gut microbiome composition and metabolites associated with diabetic heart failure in mice

Background Diabetes mellitus increases the risk of heart failure by inducing progressive myocardial structural and functional changes (diabetic cardiomyopathy, DCM). Emerging evidence implicates the gut microbiome and microbiome-derived metabolites in cardiometabolic disease, but the integrated relationships among gut community shifts, specific metabolites and progression from diabetes to heart failure remain incompletely defined. Methods Using C57BL/6J mice, we established three high-fat/high-sugar feeding plus streptozotocin models representing DCM, the intermediate stage of the diabetes-related heart failure (DHF) and diabetes-related systolic heart failure (SHF). Fecal microbiome composition was profiled by 16 S rRNA gene sequencing and predicted functional pathways were inferred (KEGG/MetaCyc). Targeted high-throughput serum metabolomics (LC-MS/MS, 600-MRM panel) identified differential metabolites. Spearman correlation analysis linked microbial genera with serum metabolites. Cardiomyocyte mitochondrial function was assessed by mitochondrial membrane potential (ΔΨm), ROS measurement and Seahorse XFe96 respiration assays. Results The composition of the mice gut microbiome differed across groups. Relative to Controls, Cryptobacteroides , Porphyromonadaceae bacterium UBA7173 and Dubosiella decreased in DCM, DHF, and SHF, while Kineothrix , Faecalibaculum , Phocaeicola_A and Lawsonibacter increased. Microbiome functional prediction found that amino acid metabolism was among the most enriched pathways. Metabolomics revealed 20 shared differential metabolites, including L‑phenylalanine, N‑acetyl‑5‑hydroxytryptamine, L‑cystine, L‑carnitine, O‑acetylcarnitine, nicotinamide N‑oxide and 1,5‑anhydro‑D‑glucitol. Pathway analysis found that Phenylalanine, tyrosine and tryptophan biosynthesis were the key metabolic pathways. Spearman correlations linked L‑phenylalanine, L‑tyrosine, L‑tryptophan with genera such as Lachnospira and Ruminiclostridium_E . Cardiomyocytes from model mice showed reduced ΔΨm, increased ROS and decreased basal, ATP, maximal respiration and spare capacity, most pronounced in SHF. Conclusions Diabetes-related heart failure in these mouse models was associated with distinct gut microbiome alterations and serum metabolic shifts. Perturbation of phenylalanine, tyrosine and tryptophan biosynthesis was identified as a candidate microbiome‑metabolome axis associated with cardiomyocyte mitochondrial dysfunction and cardiac impairment. These findings nominate microbial groups, metabolites and pathways for mechanistic validation and potential biomarkers.