Abstract
BackgroundMany available data have suggested that hyperhomocysteinaemia, an established independent risk factor for thrombosis (arterial and venous), may be associated with an increased risk of retinal vein occlusion (RVO).Aim of the studyTo evaluate homocysteine metabolism in consecutive caucasian patients affected by RVO from Northern Italy.Patients and Methods69 consecutive patients from Northern Italy (mean age 64.1 ± 14.6 yy) with recent RVO, were tested for plasma levels of homocysteine (tHcy: fasting and after loading with methionine), cyanocobalamine and folic acid levels (CMIA-Abbot) and looking for MTHFR C677T mutation (Light Cycler-Roche) and compared to 50 volunteers, enrolled as a control group.ResultsFasting levels of tHcy were significantly higher in patients than in controls: mean value 14.7 ± 7.7 vs 10.2 ± 8 nmol/ml. Post load levels were also significantly higher: mean value 42.7 ± 23.7 vs 30.4 ± 13.3 nmol/ml; Total homocysteine increase was also evaluated (i.e. Δ-tHcy) after methionine load and was also significantly higher in patients compared to control subjects: mean Δ-tHcy 27.8 ± 21.5 vs 21.0 ± 16 nmol/ml (normal value < 25 nmol/ml). Furthermore, patients affected by RVO show low folic acid and/or vitamin B12 levels, although differences with control group did not reach statistical significance. Heterozygous and homozygous MTHFR mutation were respectively in study group 46% and 29% vs control group 56% and 4%.Conclusionour data confirm that hyperhomocysteinaemia is a risk factor for RVO, and also that TT genotype of MTHFR C677T is more frequently associated with RVO: if the mutation per se is a risk factor for RVO remains an open question to be confirmed because another study from US did not reveal this aspect.Hyperomocysteinemia is modifiable risk factor for thrombotic diseases. Therefore, a screening for tHcy plasma levels in patients with recent retinal vein occlusion could allow to identify patients who might benefit from supplementation with vitamins and normalization of homocysteine levels, in fasting and after methionine load.
Highlights
Many available data have suggested that hyperhomocysteinaemia, an established independent risk factor for thrombosis, may be associated with an increased risk of retinal vein occlusion (RVO)
Hypertension was present in 55% of patients compared to 30% of control group (p: 0.014); diabetes was present in 17% of patients compared to 18% of control group (p: ns); smoking was present in 23% of patients compared to 24% of control group (p: ns); dyslipidemia was present in 26% of patients compared to 24% of control group (p: ns); glaucoma was present in 8% of patients was absent in control subjects (p: 0.039); hyperviscosity syndrome and/or vasculytis were not found in study group nor in control subjects (p: ns)
Several reports in last few years, described frequently hyperhomocysteinemia in patients affected by RVO [2934]
Summary
Many available data have suggested that hyperhomocysteinaemia, an established independent risk factor for thrombosis (arterial and venous), may be associated with an increased risk of retinal vein occlusion (RVO). Inherited thrombophilia related to clotting inhibitors deficiency (i.e. protein C, Protein S and Antithrombin III deficiencies) [11,12] has been rarely reported such as clotting XII deficiency [13], while data on the role of factor V Leiden are still matter of discussion [14,15,16,17,18] and few data are available on the role of prothrombin A20210G gene polymorphism in RVO pathogenesis [17,19]. Plasminogen deficiency and 4G/5G gene polymorphism of plasminogen activator inhibitor type 1, have been recently described as risk factors for RVO [22,23]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
