Abstract
Purpose: :
Patients infected with the human immunodeficiency virus (HIV) often show microvascular abnormalities ending up in retinal bleedings, cotton wool spots and other typical HIV related retinal pathologies. It has been hypothesized that these vascular alterations may be caused by impaired blood flow regulation, leading to focal ischemia and in turn to tissue hypoxia. In the current study, we used the vasoconstrictory response of retinal vessels to oxygen as a provocation test to assess retinal blood flow regulation in patients with HIV and healthy controls.
Methods: :
12 patients infected with HIV and 12 healthy sex and age matched volunteers have been included in this open, parallel group study. Perimacular retinal white blood cell (WBC) flux was assessed using the blue field entoptic technique. Blood flow was measured at baseline and at the end of a 15 minute 100% oxygen breathing period.
Results: :
As expected, breathing of oxygen induced a decrease in WBC flux of -29.5% ± 9.5% in healthy subjects. However, patients with HIV showed a significantly less pronounced oxygen induced decrease in WBC flux in response to oxygen (-16.2% ± 11.4% p = 0.007 between groups, ANOVA).
Conclusions: :
Patients with HIV infection show a significantly attenuated response of retinal perimacular blood flow to systemic hyperoxia. This indicates for an impaired metabolic autoregulation in this group of patients. Whether this contributes to the pathogenesis of the disease or occurs secondary to HIV infection remains to be investigated.
Clinical Trial: :
www.clinicaltrials.gov NCT00431548
Keywords: AIDS/HIV • oxygen