Enhanced gene delivery to the neonatal retina through systemic administration of tyrosine-mutated AAV9.

Delivery of therapeutic genes to a large region of the retina with minimal damage from intraocular surgery is a central goal of treatment for retinal degenerations. Recent studies have shown that AAV9 can reach the central nervous system (CNS) and retina when administered systemically to neonates, which is a promising strategy for some retinal diseases. We investigated whether the retinal transduction efficiency of systemically delivered AAV9 could be improved by mutating capsid surface tyrosines, previously shown to increase the infectivity of several AAV vectors. Specifically, we evaluated retinal transduction following neonatal intravascular administration of AAV9 vectors containing tyrosine to phenylalanine mutations at two highly conserved sites. Our results show that a novel, double tyrosine mutant of AAV9 significantly enhanced gene delivery to the CNS and retina, and that gene expression can be restricted to rod photoreceptor cells by incorporating a rhodopsin promoter. This approach provides a new methodology for the development of retinal gene therapies or creation of animal models of neurodegenerative disease.

Spinal cord excitatory amino acid receptors and plasma catecholamine autonomic responses in the conscious rabbit.

Intrathecal administration of the specific glutamate subtype receptor agonist NMDA (N-methyl-D-aspartate), or the non-NMDA receptor agonist AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid), at the level of the lower thoracic spinal cord in the conscious rabbit, produces increased levels of plasma norepinephrine and a rise in blood pressure. These responses are specifically inhibited with prior intrathecal administration of the NMDA receptor antagonist AP-5 (2-amino-5-phosphonovaleric acid) or non-NMDA receptor antagonist DNQX (6, 7-dinitroquinoxaline-2, 3-dione), respectively. In contrast, arterial baroreflex activation induced by transient hypotension following intravenous sodium nitroprusside increases levels of plasma norepinephrine which are inhibited with intrathecal AP-5, but not DNQX. The experiments are consistent with glutamate acting as a neurotransmitter in the spinal cord influencing control of sympathetic nerve function via activation of spinal cord NMDA and non-NMDA subtype receptors. The results support previous work suggesting that baroreflex function is predominantly mediated by spinal NMDA receptors and that spinal glutamate receptors are important in baroreflex control of the circulation.

Thrombolytic treatment and proteinuria.

OBJECTIVES: To determine whether patients with acute myocardial infarction undergoing thrombolysis with streptokinase develop changes in renal function. DESIGN: Prospective assessment of renal function in 60 consecutive patients admitted with acute myocardial infarction. SETTING: Tertiary referral centre and city general hospital. PATIENTS: 60 consecutive patients with acute myocardial infarction. Thirty eight were given streptokinase and 17 tissue plasminogen activator (alteplase) and five no thrombolytic agent (non-streptokinase group). MAIN OUTCOME MEASURES: Proteinuria and creatinine clearance on admission (day 1) and on days 3 and 6; serum urea and creatinine concentrations on days 1 and 7; streptokinase IgG on days 1, 2, and 7. RESULTS: Significant proteinuria (> 0.15 g/24 h) was found in 31 (82%) of the 38 patients in the streptokinase group (mean 0.47 g/24 h (95% confidence interval 0.35 to 0.6 g/24 h)) in the 24 hours after admission compared with six (27%) out of 22 in the non-streptokinase group (mean 0.17 g/24 h (0.12 to 0.2 g/24 h); P = 0.008). In the streptokinase group this decreased to the normal range by day 3 (mean 0.15 g/24 h (0.1 to 0.22 g/24 h); P = 0.0001 v baseline). Electrophoresis of urine showed the proteinuria to be glomerular in origin. Creatinine clearance and serum creatinine and urea concentrations were similar in both groups. In the streptokinase group detectable streptokinase IgG titres were found in 28 out of 32 (87%) patients. The median titre on admission was 16 (range 0-110); it fell to 3 (range 0-80; P = 0.001) by day 2 and increased to 61 (range 0-7700; P = 0.0002 v baseline) by day 7. CONCLUSIONS: Streptokinase was associated with significant early onset proteinuria of glomerular origin. This started to resolve by day 3 and resulted in no deterioration in overall renal function. The temporal relation to the initial fall in antibody titre suggests that it could be the result of immune complex deposition in the glomeruli.