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Age-related macular degeneration is associated with increased vascular endothelial growth factor, hemorheology and
P L Lip1, A D Blann, M Hope-Ross
1Haemostasis Thrombosis and Vascular Biology Unit, University Department of Medicine, City Hospital, Birmingham B18 7QH, England, UK.
Insights
This study found higher levels of vascular endothelial growth factor (VEGF), fibrinogen, plasma viscosity, and von Willebrand factor in age-related macular degeneration (ARMD) patients compared to controls. These markers suggest abnormal angiogenesis, hemorheology, and endothelial dysfunction may contribute to ARMD.
Area of Science:
- Ophthalmology
- Vascular Biology
- Biochemistry
Background:
- Age-related macular degeneration (ARMD) is a leading cause of vision loss.
- The pathogenesis of ARMD involves complex biological processes, including angiogenesis and endothelial function.
Purpose of the Study:
- To investigate laboratory evidence of abnormal angiogenesis, hemorheologic factors, endothelial damage/dysfunction, and their association with ARMD.
- To compare these markers between ARMD patients and healthy controls.
Main Methods:
- A comparative cross-sectional study involving 78 ARMD subjects and 25 healthy controls.
- Measurement of vascular endothelial growth factor (VEGF), hemorheologic factors (plasma viscosity, hematocrit, white cell count, hemoglobin, platelets), fibrinogen, and von Willebrand factor.
Main Results:
- ARMD subjects showed significantly higher plasma VEGF, von Willebrand factor, plasma fibrinogen, and plasma viscosity compared to controls.
- No significant differences were found between dry and exudative ARMD subtypes for these markers.
- Smoking status predicted plasma von Willebrand factor levels, but no other clinical predictors were identified for VEGF or fibrinogen.
Conclusions:
- The study suggests an association between markers of angiogenesis, hemorheologic factors, hemostasis, endothelial dysfunction, and ARMD.
- The interplay between abnormal angiogenesis and thrombogenesis may play a role in the pathogenesis of ARMD.
Objective:
To investigate laboratory evidence of abnormal angiogenesis, hemorheologic factors, endothelial damage/dysfunction, and age-related macular degeneration (ARMD).
Design:
Comparative cross-sectional study.
Participants:
We studied 78 subjects (26 men and 52 women; mean age 74 years; standard deviation [SD] 9.0) with ARMD attending a specialist referral clinic. Subjects were compared with 25 healthy controls (mean age, 71 years; SD, 11).
Intervention And Outcome Measures:
Levels of vascular endothelial growth factor (VEGF, an index of angiogenesis), hemorheologic factors (plasma viscosity, hematocrit, white cell count, hemoglobin, platelets), fibrinogen (an index of rheology and hemostasis), and von Willebrand factor (a marker of endothelial dysfunction) were measured.
Results:
Median plasma VEGF (225 vs. 195 pg/ml, P = 0.019) and mean von Willebrand factor (124 vs. 99 IU/dl, P = 0.0004) were greater in ARMD subjects than the controls. Mean plasma fibrinogen and plasma viscosity levels were also higher in the subjects (both P < 0.0001). There were no significant differences in other indices between cases and controls. When "dry" (drusen, atrophy, n = 28) and "exudative" (n = 50) ARMD subjects were compared, there was no significant differences in VEGF, fibrinogen, viscosity, or von Willebrand factor levels. There were no significant correlations between the measured parameters. Stepwise multiple regression analysis did not demonstrate any significant clinical predictors (age, gender, smoking, body mass index, history of vascular disease, or hypertension) for plasma VEGF or fibrinogen levels, although smoking status was a predictor of plasma von Willebrand factor levels (P < 0.05).
Conclusions:
This study suggests an association between markers of angiogenesis (VEGF), hemorheologic factors, hemostasis, endothelial dysfunction, and ARMD. The interaction between abnormal angiogenesis and the components of Virchow's triad for thrombogenesis may in part contribute to the pathogenesis of ARMD.