Tropism of engineered and evolved recombinant AAV serotypes in the rd1 mouse and ex vivo primate retina.

There is much debate on the adeno-associated virus (AAV) serotype that best targets specific retinal cell types and the route of surgical delivery-intravitreal or subretinal. This study compared three of the most efficacious AAV vectors known to date in a mouse model of retinal degeneration (rd1 mouse) and macaque and human retinal explants. Green fluorescent protein (GFP) driven by a ubiquitous promoter was packaged into three AAV capsids: AAV2/8(Y733F), AAV2/2(quad Y-F) and AAV2/2(7m8). Overall, AAV2/2(7m8) transduced the largest area of retina and resulted in the highest level of GFP expression, followed by AAV2/2(quad Y-F) and AAV2/8(Y733F). AAV2/2(7m8) and AAV2/2(quad Y-F) both resulted in similar patterns of transduction whether they were injected intravitreally or subretinally. AAV2/8(Y733F) transduced a significantly smaller area of retina when injected intravitreally compared with subretinally. Retinal ganglion cells, horizontal cells and retinal pigment epithelium expressed relatively high levels of GFP in the mouse retina, whereas amacrine cells expressed low levels of GFP and bipolar cells were infrequently transduced. Cone cells were the most frequently transduced cell type in macaque retina explants, whereas Müller cells were the predominant transduced cell type in human retinal explants. Of the AAV serotypes tested, AAV2/2(7m8) was the most effective at transducing a range of cell types in degenerate mouse retina and macaque and human retinal explants.

Early treatment of acute submacular haemorrhage secondary to wet AMD using intravitreal tissue plasminogen activator, C3F8, and an anti-VEGF agent.

PurposeAcute submacular haemorrhage secondary to wet age-related macular degeneration (AMD) has a poor prognosis for which there is currently no 'gold standard' treatment. We evaluated the efficacy of early treatment using intravitreal triple therapy of tissue plasminogen activator (tPA), expansile gas, and an anti-VEGF agent.MethodsThis retrospective case series included eight patients presenting with acute submacular haemorrhage involving the fovea. All patients received treatment with 50 µg (0.05 ml) tPA, 0.3 ml 100% perfluoropropane (C3F8), and an anti-VEGF agent (0.05 mg Ranibizumab or 1.25 mg Bevacizumab in 0.05 ml) administered via intravitreal injection. An anterior chamber paracentesis post injection or vitreous tap was performed before injection to prevent retinal vascular occlusion secondary to raised intra-ocular pressure. Outcomes assessed were visual acuity, change in macular morphology, and complications.ResultsPatients presented promptly with delay between symptom onset and clinic review being 1.9±0.6 days (mean±SD). Treatment was delivered quickly with interval from presentation to treatment being 1.1±1.2 days. Symptom onset to treatment was 3.0±1.0 days. Subfoveal haemorrhage was effectively displaced in all patients. LogMAR visual acuity improved from 1.67±0.47 at presentation to 0.63±0.33 at final follow-up (P<0.0001), a mean of 7.9±4.8 months after treatment. Central retinal thickness improved from 658.1±174.2 µm at presentation to 316.6±142.4 µm at final follow-up (P=0.0028).ConclusionsEarly treatment of submacular haemorrhage using intravitreal tPA, C3F8, and anti-VEGF was effective in significantly improving visual acuity in this series of patients who presented soon after symptom onset. Treatment was well tolerated in this group of elderly and potentially frail patients.

Long-term visual and retinopathy outcomes in a predominately type 2 diabetic patient population undergoing early vitrectomy and endolaser for severe vitreous haemorrhage.

PURPOSE: To evaluate the long-term visual outcome of type 2 diabetic patients receiving early vitrectomy and endolaser for severe vitreous haemorrhage (VH). MATERIALS AND METHODS: Retrospective case note review of 88 eyes (69 type 2 diabetics and 19 type 1 diabetics) of 80 patients who underwent vitrectomy and endolaser within 6 months of VH. Post-operative and most recent VA, in addition to long-term retinopathy grading, were analysed. A subset of patients fulfilling the criteria for the Diabetic Retinopathy Vitrectomy Study was compared with this study. RESULTS: Mean pre-operative visual acuity (VA) in the type 2 group was 0.64 logMAR, with 1 eye showing perception light (PL), 10 eyes detecting hand movements (HMs), and 7 eyes counting fingers (CFs). At the 2-week post-operative visit, the mean VA had improved to 0.46 logMAR, with two eyes showing PL, two eyes detecting HM, and one eye CF (P=0.0002); at the last review, mean VA score was 0.36 logMAR, with three eyes showing PL and four eyes detecting HM (P=0.0008). Mean pre-operative VA in the type 1 group was 0.47 logMAR, with one eye showing PL, one eye detecting HM, and two eyes CF. At the 2-week post-operative visit, the mean VA had improved to 0.37 logMAR, with one eye showing PL (P=0.002), and at the latest review, the mean VA was 0.20 logMAR (P=0.027). CONCLUSION: Our study shows that type 2 DM patients can observe improvement in VA and stabilisation of their proliferative retinopathy after early vitrectomy and endolaser for vitreous haemorrahage, which is maintained after long-term follow-up.

A geographical information system technique for record-matching in a study of cancer deaths in welders.

Retrospective studies are frequently complicated by incomplete worker identifiers. We encountered this problem when evaluating the risk of cancer death in a welding cohort. We dealt with it by developing birth-date ranges for each welder with unknown birth dates and using geographical information system techniques in conjunction with last name, gender, and birth-date range to assign death certificates to welders on the basis of residential proximity to the worksite. Deaths for total malignant cancers and lung/tracheobronchial/pleural cancers among these welders were not significantly different from those in county, state, and US populations, using standardized mortality ratios. The ratios in our study subjects were consistent with ratios found in other published welder cohorts.

Plasma fibrinogen in diabetes mellitus.

Plasma fibrinogen was measured in 285 diabetics (age range 15-85 years) and 209 controls (age range 23-74 years). Plasma fibrinogen concentration showed a positive skew distribution and an approximate normal distribution was obtained by log transformation. The mean log plasma fibrinogen in the diabetics was significantly increased (p less than 0.0001). Patients treated with a sulphonylurea (n = 81) had the highest mean log plasma fibrinogen concentration and this was significantly higher than in patients treated with insulin (n = 76; p less than 0.01), biguanides (n = 28; p less than 0.01) or sulphonyluera plus biguanides (n = 38; p less than 0.05). The biganide treated group had the lowest mean log plasma fibrinogen concentrations. No correlation was found between plasma fibrinogen and blood glucose, duration of diabetes or the presence of complications. Subjects with proliferative retinopathy (n = 38) had a similar mean plasma fibrinogen to those with background retinopathy (n = 55). Twenty-two maturity onset diabetics treated with a sulphonylurea and followed prospectively showed a significant increase in plasma fibrinogen after five months (p less than 0.0001), while a control diet treated group showed no alteration in plasma fibrinogen. It is concluded that plasma fibrinogen is significantly increased in diabetics and apart from age, the main factor related to the increase is treatment with sulphonylureas. It remains speculative whether this association has any correlation with long term cardiovascular morbidity.

Metformin and clofibrate in maturity onset diabetes mellitus: advantages of combined treatment.

Blood glucose, lipoproteins, non-esterified fatty acids, fibrinogen and intermediary metabolites were measured in twenty-two diet failed maturity onset diabetics during a double blind crossover study of metformin (1.7 g/day) or clofibrate (2 g/day) therapy. Patients received combined therapy for a final two month period. Four patients had 12 hour metabolic profiles performed during each treatment period. A more significant improvement in fasting blood glucose and glycosuria occured with metformin and combined therapy. However, clofibrate and combined therapy significantly decreased total and low density lipoprotein cholesterol, total and very low density lipoprotein triglyceride and fibrinogen. Metabolic profiles demonstrated significant elevations of blood lactate and alanine with metformin treatment but these parameters returned to normal with combined therapy. Non-esterified fatty acids and glycerol were significantly lower during combined therapy compared with metformin or clofibrate alone. Despite the recent adverse report on clofibrate, this study indicates that the addition of clofibrate to metformin therapy may have advantages in the management of maturity onset diabetics.