title: The relationship of systemic markers of renal function and vascular function with retinal blood vessel responses.
abstract: OBJECTIVE
  To test the hypothesis of a significant relationship between systemic markers of renal and vascular function (processes linked to cardiovascular disease and its development) and retinal microvascular function in diabetes and/or cardiovascular disease.
  
  
  METHODS
  Ocular microcirculatory function was measured in 116 patients with diabetes and/or cardiovascular disease using static and continuous retinal vessel responses to three cycles of flickering light. Endothelial function was evaluated by von Willebrand factor (vWf), endothelial microparticles and soluble E selectin, renal function by serum creatinine, creatinine clearance and estimated glomerular filtration rate (eGFR). HbA1c was used as a control index.
  
  
  RESULTS
  Central retinal vein equivalence and venous maximum dilation to flicker were linked to HbA1c (both p < 0.05). Arterial reaction time was linked to serum creatinine (p = 0.036) and eGFR (p = 0.039); venous reaction time was linked to creatinine clearance (p = 0.018). Creatinine clearance and eGFR were linked to arterial maximum dilatation (p < 0.001 and p = 0.003, respectively) and the dilatation amplitude (p = 0.038 and p = 0.048, respectively) responses in the third flicker cycle. Of venous responses to the first flicker cycle, HbA1c was linked to the maximum dilation response (p = 0.004) and dilatation amplitude (p = 0.017), vWf was linked to the maximum constriction response (p = 0.016), and creatinine clearance to the baseline diameter fluctuation (p = 0.029). In the second flicker cycle, dilatation amplitude was linked to serum creatinine (p = 0.022).
  
  
  CONCLUSIONS
  Several retinal blood vessel responses to flickering light are linked to glycaemia and renal function, but only one index is linked to endothelial function. Renal function must be considered when interpreting retinal vessel responses.
authors.affiliation: Aston University, School of Life and Health Sciences, Aston Triangle, B4 7ET, Birmingham, UK.
authors.forename: R
authors.initials: R
authors.lastname: Heitmar
authors.affiliation: Department of Cardiology, City Hospital, Birmingham, B18 7QH, UK.
authors.forename: C
authors.initials: C
authors.lastname: Varma
authors.affiliation: Department of Diabetes and Endocrinology, City Hospital, Birmingham, B18 7QH, UK.
authors.forename: P
authors.initials: P
authors.lastname: De
authors.affiliation: University of Birmingham Institute for Cardiovascular Sciences, City Hospital, Birmingham, B18 7QH, UK.
authors.forename: Y C
authors.initials: YC
authors.lastname: Lau
authors.affiliation: University of Birmingham Institute for Cardiovascular Sciences, City Hospital, Birmingham, B18 7QH, UK. andrew.blann@hotmail.com.
authors.forename: A D
authors.initials: AD
authors.lastname: Blann
mesh_terms: D015415:Biomarkers / Q000378:metabolism*; D001794:Blood Pressure / Q000502:physiology; D002318:Cardiovascular Diseases / Q000378:metabolism / Q000503:physiopathology; D003404:Creatinine / Q000378:metabolism; D003920:Diabetes Mellitus / Q000097:blood* / Q000503:physiopathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D010775:Photic Stimulation; D012171:Retinal Vessels / Q000503:physiopathology*; D014664:Vasodilation / Q000502:physiology*
chemical_list: D015415:Biomarkers; D003404:Creatinine; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: Diabetes; Microcirculation; Renal function; Retinal vessels; Vascular function