{
  "abstract": "Introduction Type II diabetes mellitus is a rapidly growing worldwide health challenge. Diabetic cardiomyopathy is a heart muscle disease caused independently by a diabetic milieu and is driven by metabolic dysfunction, oxidative stress, calcium mishandling and mitochondrial impairment. Classical disease models are deficient in replicating human-specific disease mechanisms. Induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) provide a strong patient-specific model for investigating cellular and molecular changes in diabetic cardiomyopathy, as they retain patient-specific metabolic and epigenetic characteristics.Methods Human iPSCs derived from diabetic (DB) and non-diabetic (ND) donor groups (n = 3 each) were maintained under feeder-free conditions until confluence. Cardiac differentiation was performed using a commercially available differentiation kit that modulates the WNT/β-catenin pathway with small molecules to promote mesodermal and cardiac lineage commitment. After day 15 of differentiation, RT-PCR, Western blotting, and immunocytochemistry were performed to confirm the presence of cardiac markers and compare the DB and ND iPS-CMs groups. Flow cytometry analysed cell populations and phenotypic changes related to diabetic remodelling. Functional assays measured mitochondrial reactive oxygen species (MitoSOX), calcium transients (Fura-2), and apoptotic index (TUNEL). RNA sequencing revealed differentially expressed genes and pathways, which were validated through bioinformatic analyses and PCR.Results Functional iPS-CMs displayed spontaneous contractions and expressed cardiac markers like troponin T, confirming effective differentiation. Relative to controls, DB iPS-CMs exhibited stressful alterations accompanied by hypertrophic and fibrotic changes, such as increased mitochondrial reactive oxygen species levels and apoptosis. Visual analysis of the mitochondrial network revealed greater fission rates in DB iPS-CMs, while the collagen contraction assay showed increased ECM remodelling and collagen deposition.Flow cytometry analysis revealed an increased forward scatter in DB iPS-CMs, indicative of a hypertrophic phenotype. Furthermore, shifts in PDGFRα-positive populations and a higher proportion of α-SMA-positive cells is suggestive of increased cardiac fibroblast proliferation and myofibroblast activation. Calcium uptake assays demonstrated elevated basal intracellular calcium levels in DB iPS-CMs that reflect deficient SERCA2a function, accompanied by increased calcium peaks and prolonged recovery kinetics following Isoprenaline administration. Whilst Carbachol suppressed calcium transients in control cardiomyocytes, DB iPS-CMs exhibited inefficient calcium clearance and reduced functional reserve.RNA sequencing identified 1,412 differentially expressed genes. Pathway enrichment and gene ontology revealed significant upregulation of gene networks related to cardiac hypertrophy, fibrosis, extracellular matrix remodelling, and ion channel regulation in DB iPS-CMs. Notably, TGF-β and WNT/β-catenin signalling pathways were prominently enriched, both serving as key regulators of pathological cardiac remodelling. The convergence of WNT and TGF-β signalling pathways indicates coordinated transcriptional mechanisms that drive maladaptive hypertrophic and fibrotic remodelling in the diabetic cardiac phenotype.Future Work Ongoing research aims to investigate novel pathways and utilise targeted overexpression and knockout strategies to elucidate their causal roles in disease pathogenesis. Collectively, the mechanistic and functional assays corroborate the transcriptomic findings, demonstrating that DB iPS-CMs retain disease-relevant epigenetic and functional characteristics inherent from their donors. This human-based model offers significant potential for investigating the mechanisms underlying diabetic cardiomyopathy and evaluating therapeutic strategies to restore function and longevity.",
  "authors": [
    {
      "affiliations": [
        "Queen’s University Belfast, Belfast, United Kingdom",
        "King Abdulaziz University, Jeddah, Saudi Arabia"
      ],
      "name": "Asim Tashkandi"
    },
    {
      "affiliations": [
        "Queen’s University Belfast, Belfast, United Kingdom"
      ],
      "name": "Alyssa Tong"
    },
    {
      "affiliations": [
        "Queen’s University Belfast, Belfast, United Kingdom"
      ],
      "name": "Refik Kuburas"
    },
    {
      "affiliations": [
        "Queen’s University Belfast, Belfast, United Kingdom"
      ],
      "name": "Derek Brazil"
    },
    {
      "affiliations": [
        "Queen’s University Belfast, Belfast, United Kingdom"
      ],
      "name": "Andriana Margariti"
    }
  ],
  "title": "550 Investigating the mechanisms underlying cardiomyopathy in diabetes mellitus using iPS-derived cardiomyocytes",
  "uid": "22f5837a-018e-5c05-af88-e57d9bc8baeb"
}