title: Hemorheologic abnormalities associated with HIV infection: in vivo assessment of retinal microvascular blood flow.
abstract: OBJECTIVE
  To evaluate retinal microvascular blood flow in human immunodeficiency virus (HIV)-infected individuals using scanning laser Doppler flowmetry (SLDF) and to seek correlations between flow and various laboratory measures that may predict alterations in flow.
  
  
  METHODS
  The Heidelberg Retina Flowmeter and SLDF software were used to acquire in vivo retinal blood flow data from 24 HIV-infected individuals and 16 HIV-negative control subjects. In each subject, separate scans were performed in each of six retinal regions: nasal parapapillary retina; macula; and the superior, nasal, inferior, and temporal periphery. Erythrocyte aggregation (assessed in vitro by a fully automatic erythrocyte aggregometer and by zeta sedimentation ratio [ZSR, a hematocrit-independent sedimentation rate]), serum fibrinogen level, plasma viscosity, and leukocyte rigidity (assessed in vitro with a cell transit analyzer) were compared with flow in selected regions.
  
  
  RESULTS
  Flow was significantly higher in the periphery (superior, nasal, inferior, temporal) than in the posterior retina (nasal parapapillary retina, macula). Flow was highest in the temporal periphery for both HIV-infected subjects and control subjects. Flow in the posterior retina was significantly lower in HIV-infected subjects than in control subjects (P < 0.0001). Among HIV-infected individuals, flow in the macula correlated negatively with ZSR (r = -0.397, P = 0.0547) and leukocyte rigidity (r = -0.505, P = 0.0119).
  
  
  CONCLUSIONS
  Microvascular blood flow in the posterior retina is reduced in HIV-infected individuals. Both increased erythrocyte aggregation and increased leukocyte rigidity contribute to this hemorheologic abnormality.
authors.affiliation: Ocular Inflammatory Disease Center, Jules Stein Eye Institute, UCLA, Los Angeles, CA 90095-7003, USA.
authors.forename: Hajir
authors.initials: H
authors.lastname: Dadgostar
authors.forename: Gary N
authors.initials: GN
authors.lastname: Holland
authors.forename: Xin
authors.initials: X
authors.lastname: Huang
authors.forename: Adnan
authors.initials: A
authors.lastname: Tufail
authors.forename: Alisa
authors.initials: A
authors.lastname: Kim
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Fisher
authors.forename: William G
authors.initials: WG
authors.lastname: Cumberland
authors.forename: Herbert J
authors.initials: HJ
authors.lastname: Meiselman
authors.forename: Arthur
authors.initials: A
authors.lastname: Benjamin
authors.forename: Dirk-Uwe
authors.initials: DU
authors.lastname: Bartsch
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D001799:Blood Sedimentation; D001809:Blood Viscosity; D017726:Cytomegalovirus Retinitis / Q000097:blood / Q000209:etiology / Q000503:physiopathology; D004903:Erythrocyte Aggregation; D004907:Erythrocyte Deformability; D005340:Fibrinogen / Q000032:analysis; D015658:HIV Infections / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008833:Microcirculation / Q000502:physiology; D008875:Middle Aged; D012166:Retinal Hemorrhage / Q000097:blood / Q000209:etiology / Q000503:physiopathology*; D012171:Retinal Vessels / Q000502:physiology*
chemical_list: D005340:Fibrinogen