Anticoagulation therapy a risk factor for the development of chronic subdural hematoma.

OBJECTIVE: Chronic subdural hematoma (CSDH) is a common disease among the elderly and with increasing incidence we have chosen to focus on associations between development and recurrence of CSDH and anticoagulation and/or antiplatelet agent therapy. METHODS: We conducted a retrospective review of 239 patients undergoing surgery for CSDH over a period of six years (2006-2011). Risk factors such as age, head trauma, anticoagulant and/or antiplatelet agent therapy and co-morbidity were investigated along with gender, coagulation status, laterality, surgical method and recurrence. RESULTS: Seventy-two percent of the patients were male and the mean age was 71.8 years (range 28-97 years). Previous fall with head trauma was reported in 60% of the patients while 16% were certain of no previous head trauma. The majority of patients (63%) in the non-trauma group were receiving anticoagulants and/or antiplatelet agent therapy prior to CSDH presentation, compared to 42% in the trauma group. Twenty-four percent experienced recurrence of the CSDH. There was no association between recurrence and anticoagulant and/or antiplatelet agent therapy. CONCLUSION: Anticoagulant and/or antiplatelet aggregation agent therapy is more prevalent among non-traumatic CSDH patients but does not seem to influence the rate of CSDH recurrence.

Suppression of retinal neovascularization by erythropoietin siRNA in a mouse model of proliferative retinopathy.

PURPOSE: Erythropoietin (EPO), an oxygen-regulated hormone stimulating erythrocyte production, was recently found to be critical for retinal angiogenesis. EPO mRNA expression levels in retina are highly elevated during the hypoxia-induced proliferation phase of retinopathy. The authors investigated the inhibition of retinal EPO mRNA expression with RNA interference as a potential strategy to suppress retinal neovascularization and to prevent proliferative retinopathy. METHODS: The authors used a mouse model of oxygen-induced retinopathy. Retinal EPO and Epo receptor (EpoR) expression during retinopathy development were quantified with real-time RT-PCR in whole retina and on laser-captured retinal vessels and neuronal layers. Retinal hypoxia was assessed with an oxygen-sensitive hypoxyprobe. A small interference RNA (siRNA) targeting EPO or control negative siRNA was injected intravitreally at postnatal (P) day 12, P14, and P15 during the hypoxic phase, and the effect on neovascularization was evaluated in retinal flatmounts at P17. RESULTS: Retinal EPO mRNA expression in total retina was suppressed during the initial phase of vessel loss in retinopathy and was significantly elevated during the hypoxia-induced proliferative phase in all three neuronal layers in the retina, corresponding to an increased level of retinal hypoxia. EpoR mRNA expression levels also increased during the second neovascular phase, specifically in hypoxia-induced neovascular vessels. Intravitreous injection of EPO siRNA effectively inhibited approximately 60% of retinal EPO mRNA expression and significantly suppressed retinal neovascularization by approximately 40%. CONCLUSIONS: Inhibiting EPO mRNA expression with siRNA is effective in suppressing retinal neovascularization, suggesting EPO siRNA is a potentially useful pharmaceutical intervention for treating proliferative retinopathy.