{
  "abstract": "Introduction Lipoprotein(a) [Lp(a)] is an independent, genetically determined predictor of cardiovascular disease; however, its interaction with vascular repair mechanisms is unclear. Increased intracellular reactive oxygen species (ROS) cause oxidative stress and impair cellular homeostasis. We hypothesize that ROS expression in vascular regenerative (VR) cells differs between people with elevated versus non-elevated Lp(a).Methods This sub-analysis of the cross-sectional, observational Lp(a)-VRCE study compared the frequencies and absolute cell counts of VR cell subsets with high intracellular ROS levels between people with an Lp(a)≥100nmol/L (High Lp(a); n=20) and people with an Lp(a)<100nmol/L (Low Lp(a); n=20). Peripheral blood mononuclear cells were subjected to multi-chromatic flow cytometry analyses based on high aldehyde dehydrogenase (ALDH) activity, a cytoprotective enzyme conserved in progenitor cells, in combination with side scatter property (SSC) and ROS expression.Results Baseline characteristics are shown in table 1. The frequency and absolute cell counts of ALDHhiSSClow primitive progenitor cells with high intracellular ROS expression was similar between the High and Low Lp(a) groups. There was a lower frequency of ALDHhiSSCmid monocyte precursor cells with high intracellular ROS expression in the High Lp(a) group compared to the Low Lp(a) group (84.01 vs 89.96%; p=0.02). There was an increased absolute cell count of ALDHhiSSChi granulocyte precursor cells with high intracellular ROS expression in the High Lp(a) group compared to the Low Lp(a) group (5915 vs 1895 cells; p=0.04). All other frequencies and cell counts were similar between the two Lp(a) groups (figure 1).Conclusion Intracellular ROS expression was similar in pro-vascular primitive progenitor cells, lower in monocyte precursor cells, and higher in granulocyte precursor cells in people with elevated versus non-elevated Lp(a). Further investigation is warranted to understand the impact of Lp(a) on vascular repair mechanisms.Abstract 17 Table 1Data are presented as mean ± standard deviation or n (%). Between-group differences in continuous variables were calculated with the 2-sided student’s t-test assuming unequal variance. Categorical variables were compared using the Fisher exact test Abbreviations: ASCVD, atherosclerotic cardiovascular disease; BMI, body mass index; eGFR, estimated glomerular filtration rate; HbA1c, glycated haemoglobin; HDL-C, high-density lipoprotein cholesterol; hs-CRP, high sensitivity C-reactive protein; LDL-C, low-density lipoprotein cholesterol; Lp(a), lipoprotein (a)Abstract 17 Figure 1People with an Lp(a) ≥100 nmol/L had lower frequency of ALDHhiSSCmid monocyte precursor cells with high ROS content and higher absolute count of ALDHhiSSChi granulocyte precursor cells with high ROS content",
  "authors": [
    {
      "affiliations": [
        "School of Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland"
      ],
      "name": "M Moroney"
    },
    {
      "affiliations": [
        "School of Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland"
      ],
      "name": "JH Casey"
    },
    {
      "affiliations": [
        "Division of Cardiac Surgery, St Michael’s Hospital of Unity Health Toronto, Toronto, Canada",
        "Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada",
        "Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada"
      ],
      "name": "A Krishnaraj"
    },
    {
      "affiliations": [
        "Division of Cardiac Surgery, St Michael’s Hospital of Unity Health Toronto, Toronto, Canada",
        "Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada"
      ],
      "name": "Y Pan"
    },
    {
      "affiliations": [
        "Division of Cardiac Surgery, St Michael’s Hospital of Unity Health Toronto, Toronto, Canada",
        "Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada",
        "Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada"
      ],
      "name": "F Dennis"
    },
    {
      "affiliations": [
        "Division of Cardiac Surgery, St Michael’s Hospital of Unity Health Toronto, Toronto, Canada",
        "Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada",
        "Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada"
      ],
      "name": "A He"
    },
    {
      "affiliations": [
        "Division of Cardiac Surgery, St Michael’s Hospital of Unity Health Toronto, Toronto, Canada",
        "Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada",
        "Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada"
      ],
      "name": "B Park"
    },
    {
      "affiliations": [
        "School of Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland"
      ],
      "name": "R Verma"
    },
    {
      "affiliations": [
        "Division of Cardiac Surgery, St Michael’s Hospital of Unity Health Toronto, Toronto, Canada",
        "Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada",
        "Division of Endocrinology and Metabolism, St. Michael’s Hospital of Unity Health Toronto, Toronto, Canada"
      ],
      "name": "H Teoh"
    },
    {
      "affiliations": [
        "Division of Cardiac Surgery, St Michael’s Hospital of Unity Health Toronto, Toronto, Canada",
        "Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada"
      ],
      "name": "A Quan"
    },
    {
      "affiliations": [
        "Department of Cardiology, University of Texas Southwestern Medical Center, Dallas, USA"
      ],
      "name": "A Pandey"
    },
    {
      "affiliations": [
        "Department of Medicine, University of Mississippi School of Medicine, Jackson, USA"
      ],
      "name": "J Butler"
    },
    {
      "affiliations": [
        "Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada",
        "Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada",
        "Department of Physiology, University of Toronto, Toronto, Canada",
        "Department of Anesthesia, St. Michael’s Hospital of Unity Health Toronto, Toronto, Canada"
      ],
      "name": "CD Mazer"
    },
    {
      "affiliations": [
        "Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada",
        "Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada",
        "Department of Physiology and Toxicology, Western University, London, Canada",
        "Molecular Medicine Research Laboratories, Robarts Research Institute, London, Canada"
      ],
      "name": "DA Hess"
    },
    {
      "affiliations": [
        "Division of Cardiac Surgery, St Michael’s Hospital of Unity Health Toronto, Toronto, Canada",
        "Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada",
        "Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada",
        "Department of Surgery, University of Toronto, Toronto, Canada"
      ],
      "name": "S Verma"
    }
  ],
  "title": "17 Reactive oxygen species expression in vascular regenerative cells in people with elevated lipoprotein(a)",
  "uid": "e91424cf-133e-538c-856e-cda18ef2565e"
}