title: Metformin improves the angiogenic potential of human CD34⁺ cells co-incident with downregulating CXCL10 and TIMP1 gene expression and increasing VEGFA under hyperglycemia and hypoxia within a therapeutic window for myocardial infarction.
abstract: BACKGROUND
  Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in patients with diabetes mellitus (DM). To identify the most effective treatment for CVD, it is paramount to understand the mechanism behind cardioprotective therapies. Although metformin has been shown to reduce CVD in Type-2 DM clinical trials, the underlying mechanism remains unexplored. CD34(+) cell-based therapies offer a new treatment approach to CVD. The aim of this study was to investigate the effect of metformin on the angiogenic properties of CD34(+) cells under conditions mimicking acute myocardial infarction in diabetes.
  
  
  METHODS
  CD34(+) cells were cultured in 5.5 or 16.5 mmol/L glucose ± 0.01 mmol/L metformin and then additionally ± 4 % hypoxia. The paracrine function of CD34(+) cell-derived conditioned medium was assessed by measuring pro-inflammatory cytokines, vascular endothelial growth factor A (VEGFA), and using an in vitro tube formation assay for angiogenesis. Also, mRNA of CD34(+) cells was assayed by microarray and genes of interest were validated by qRT-PCR.
  
  
  RESULTS
  Metformin increased in vitro angiogenesis under hyperglycemia-hypoxia and augmented the expression of VEGFA. It also reduced the angiogenic-inhibitors, chemokine (C-X-C motif) ligand 10 (CXCL10) and tissue inhibitor of metalloproteinase 1 (TIMP1) mRNAs, which were upregulated under hyperglycemia-hypoxia. In addition metformin, increased expression of STEAP family member 4 (STEAP4) under euglycemia, indicating an anti-inflammatory effect.
  
  
  CONCLUSIONS
  Metformin has a dual effect by simultaneously increasing VEGFA and reducing CXCL10 and TIMP1 in CD34(+) cells in a model of the diabetic state combined with hypoxia. Therefore, these angiogenic inhibitors are promising therapeutic targets for CVD in diabetic patients. Moreover, our data are commensurate with a vascular protective effect of metformin and add to the understanding of underlying mechanisms.
authors: Institute of Cellular Medicine, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK. sbakhashab@kau.edu.sa.|Biochemistry Department, King Abdulaziz University, Jeddah, Saudi Arabia. sbakhashab@kau.edu.sa.|Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia. sbakhashab@kau.edu.sa.
authors: Sherin
authors: S
authors: Bakhashab
authors: Institute of Cellular Medicine, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK. fahad.ahmed@newcastle.ac.uk.|Queen Elizabeth Hospital, Gateshead, Newcastle upon Tyne, UK. fahad.ahmed@newcastle.ac.uk.
authors: Fahad W
authors: FW
authors: Ahmed
authors: Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia. hschulten@kau.edu.sa.
authors: Hans-Juergen
authors: HJ
authors: Schulten
authors: Institute of Cellular Medicine, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK. ayatbashir@yahoo.co.uk.
authors: Ayat
authors: A
authors: Bashir
authors: Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia. skarim@kau.edu.sa.
authors: Sajjad
authors: S
authors: Karim
authors: Biochemistry Department, King Abdulaziz University, Jeddah, Saudi Arabia. alalmalki@kau.edu.sa.
authors: Abdulrahman L
authors: AL
authors: Al-Malki
authors: Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia. mgari@kau.edu.sa.
authors: Mamdooh A
authors: MA
authors: Gari
authors: Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia. aabuzenadah@kau.edu.sa.
authors: Adel M
authors: AM
authors: Abuzenadah
authors: Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia. chaudhary@kau.edu.sa.
authors: Adeel G
authors: AG
authors: Chaudhary
authors: Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia. mhalqahtani@kau.edu.sa.
authors: Mohammed H
authors: MH
authors: Alqahtani
authors: Biochemistry Department, King Abdulaziz University, Jeddah, Saudi Arabia. slary@kau.edu.sa.
authors: Sahira
authors: S
authors: Lary
authors: Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia. fahmed1@kau.edu.sa.
authors: Farid
authors: F
authors: Ahmed
authors: Institute of Cellular Medicine, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK. Jolanta.Weaver@newcastle.ac.uk.|Queen Elizabeth Hospital, Gateshead, Newcastle upon Tyne, UK. Jolanta.Weaver@newcastle.ac.uk.
authors: Jolanta U
authors: JU
authors: Weaver
mesh_terms: D043925:Angiogenesis Inducing Agents / Q000494:pharmacology*; D018952:Antigens, CD34 / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D015687:Cell Hypoxia; D002478:Cells, Cultured; D054357:Chemokine CXCL10 / Q000235:genetics / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D020869:Gene Expression Profiling; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D006801:Humans; D006943:Hyperglycemia / Q000188:drug therapy* / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008687:Metformin / Q000494:pharmacology*; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D013234:Stem Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
chemical_list: D043925:Angiogenesis Inducing Agents; D018952:Antigens, CD34; D015415:Biomarkers; C114753:CXCL10 protein, human; D054357:Chemokine CXCL10; D007004:Hypoglycemic Agents; D008565:Membrane Proteins; C560822:TIMP1 protein, human; D019715:Tissue Inhibitor of Metalloproteinase-1; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D008687:Metformin; D010088:Oxidoreductases; C503310:STEAP4 protein, human