| Autor: |
Langbøl, Mia, Baskaran, Thisayini, Tiedemann, Daniel, Saruhanian, Sarkis, Katrine Toft‐Kehler, Anne, Koch Jensen, Peter, Skov Jensen, Peter, Vidiendal Olsen, Niels, Vohra, Rupali, Kolko, Miriam |
| Předmět: |
|
| Zdroj: |
Acta Ophthalmologica (1755375X); Dec2019 Supplement S263, Vol. 97, pN.PAG-N.PAG, 1p |
| Abstrakt: |
Purpose: Autoregulation is essential for a constant circulation of O2. The apparent dissimilarity of vulnerability towards increased intraocular pressure in patients with normal‐tension glaucoma (NTGs) and individuals with ocular hypertension (OHTs) has been linked to disturbed autoregulation. The retina is particularly O2‐dependent and susceptible towards oxidative stress. The purpose was to evaluate the impact of a fluctuating O2 level on retinal vessel diameters and plasma levels of vasoregulators, nitric oxide (NO) and endothelin‐1 (ET‐1), and total antioxidant capacity (TAC) in strictly characterized NTGs, OHTs and age‐matched controls. Methods: NTGs (n = 10–16), OHTs (n = 9–10) and controls (n = 9–14) were exposed to 2 h of hypoxia followed by 30 min of normoxia. Fundus pictures and blood samples were taken before hypoxia ("baseline"), during hypoxia ("hypoxia") and after hypoxia ("recovery"). NO, ET‐1 and TAC was measured in plasma. Retinal arterial and vein diameters were measured with MATLAB. Results: Retinal arteries dilated in NTGs and OHTs during hypoxia, while controls constricted. No significant changes were seen in retinal veins. During hypoxia controls and NTGs increased plasma levels of ET‐1 and NTGs sustained a high level in recovery. OHTs did not regulate ET‐1 but maintained a lower level compared to NTGs during hypoxia and recovery. No significant differences were seen in NO. OHTs had a higher TAC compared to NTGs and controls throughout the experiment. Conclusions: The present study suggests a link between NTG and dysfunctional autoregulation. ET‐1 increase in controls and NTGs during hypoxia. As a vasoconstrictor, a vascular constriction is expected as evident in controls. The observed dilation in NTGs therefore might indicate that molecular mechanisms for vasoregulation are abolished. Surprisingly, OHTs present a similar pattern of autoregulation to NTGs but there is a prominent difference in the TAC. The higher level of TAC in OHTs compared to NTGs and controls indicates that the antioxidant defence might be important in providing resistance towards glaucomatous neurodegeneration. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
Plný text