TY - JOUR
T1 - Real-time imaging of single neuronal cell apoptosis in patients with glaucoma
AU - Cordeiro, Maria F.
AU - Normando, Eduardo M.
AU - Cardoso, M. Jorge
AU - Miodragovic, Serge
AU - Jeylani, Seham
AU - Davis, Benjamin M.
AU - Guo, Li
AU - Ourselin, Sebastien
AU - A'Hern, Roger
AU - Bloom, Philip A.
PY - 2017/6
Y1 - 2017/6
N2 - Retinal cell apoptosis occurs in many ocular neurodegenerative conditions including glaucoma-the major cause of irreversible blindness worldwide. Using a new imaging technique that we have called DARC (detection of apoptosing retinal cells), which until now has only been demonstrated in animal models, we assessed if annexin 5 labelled with fluorescent dye DY-776 (ANX776) could be used safely in humans to identify retinal cell apoptosis. Eight patients with glaucomatous neurodegeneration and evidence of progressive disease, and eight healthy subjects were randomly assigned to intravenous ANX776 doses of 0.1, 0.2, 0.4 and 0.5 mg in an open-label, phase 1 clinical trial. In addition to assessing the safety, tolerability and pharmacokinetics of ANX776, the study aimed to explore whether DARC could successfully visualize individual retinal cell apoptosis in vivo in humans, with the DARC count defined as the total number of unique ANX776-labelled spots. DARC enabled retinal cell apoptosis to be identified in the human retina using ANX776. Single ANX776-labelled cells were visualized in a dose-dependent pattern (P50.001) up to 6 h after injection. The DARC count was significantly higher (2.37-fold, 95% confidence interval: 1.4-4.03, P = 0.003) in glaucoma patients compared to healthy controls, and was significantly (P = 0.045) greater in patients who later showed increasing rates of disease progression, based on either optic disc, retinal nerve fibre layer or visual field parameters. Additionally, the DARC count significantly correlated with decreased central corneal thickness (Spearman's R = 0.68, P = 0.006) and increased cup-disc ratios (Spearman's R = 0.47, P = 0.038) in glaucoma patients and with increased age (Spearman's R = 0.77, P = 0.001) in healthy controls. Finally, ANX776 was found to be safe and well-tolerated with no serious adverse events, and a short half-life (10-36 min). This proof-of-concept study demonstrates that retinal cell apoptosis can be identified in the human retina with increased levels of activity in glaucomatous neurodegenerative disease. To our knowledge, this is the first time individual neuronal apoptosis has been visualized in vivo in humans and is the first demonstration of detection of individual apoptotic cells in a neurodegenerative disease. Furthermore, our results suggest the level of apoptosis ('DARC count') is predictive of disease activity, indicating the potential of DARC as a surrogate marker. Although further trials are clearly needed, this study validates experimental findings supporting the use of DARC as a method of detection and monitoring of patients with glaucomatous neurodegeneration, where retinal ganglion cell apoptosis is an established process and where there is a real need for tools to non-invasively assess treatment efficacy.
AB - Retinal cell apoptosis occurs in many ocular neurodegenerative conditions including glaucoma-the major cause of irreversible blindness worldwide. Using a new imaging technique that we have called DARC (detection of apoptosing retinal cells), which until now has only been demonstrated in animal models, we assessed if annexin 5 labelled with fluorescent dye DY-776 (ANX776) could be used safely in humans to identify retinal cell apoptosis. Eight patients with glaucomatous neurodegeneration and evidence of progressive disease, and eight healthy subjects were randomly assigned to intravenous ANX776 doses of 0.1, 0.2, 0.4 and 0.5 mg in an open-label, phase 1 clinical trial. In addition to assessing the safety, tolerability and pharmacokinetics of ANX776, the study aimed to explore whether DARC could successfully visualize individual retinal cell apoptosis in vivo in humans, with the DARC count defined as the total number of unique ANX776-labelled spots. DARC enabled retinal cell apoptosis to be identified in the human retina using ANX776. Single ANX776-labelled cells were visualized in a dose-dependent pattern (P50.001) up to 6 h after injection. The DARC count was significantly higher (2.37-fold, 95% confidence interval: 1.4-4.03, P = 0.003) in glaucoma patients compared to healthy controls, and was significantly (P = 0.045) greater in patients who later showed increasing rates of disease progression, based on either optic disc, retinal nerve fibre layer or visual field parameters. Additionally, the DARC count significantly correlated with decreased central corneal thickness (Spearman's R = 0.68, P = 0.006) and increased cup-disc ratios (Spearman's R = 0.47, P = 0.038) in glaucoma patients and with increased age (Spearman's R = 0.77, P = 0.001) in healthy controls. Finally, ANX776 was found to be safe and well-tolerated with no serious adverse events, and a short half-life (10-36 min). This proof-of-concept study demonstrates that retinal cell apoptosis can be identified in the human retina with increased levels of activity in glaucomatous neurodegenerative disease. To our knowledge, this is the first time individual neuronal apoptosis has been visualized in vivo in humans and is the first demonstration of detection of individual apoptotic cells in a neurodegenerative disease. Furthermore, our results suggest the level of apoptosis ('DARC count') is predictive of disease activity, indicating the potential of DARC as a surrogate marker. Although further trials are clearly needed, this study validates experimental findings supporting the use of DARC as a method of detection and monitoring of patients with glaucomatous neurodegeneration, where retinal ganglion cell apoptosis is an established process and where there is a real need for tools to non-invasively assess treatment efficacy.
KW - Apoptosis
KW - Glaucoma
KW - Real-time visualization
KW - Retinal imaging
UR - http://www.scopus.com/inward/record.url?scp=85021929078&partnerID=8YFLogxK
U2 - 10.1093/brain/awx088
DO - 10.1093/brain/awx088
M3 - Article
C2 - 28449038
AN - SCOPUS:85021929078
SN - 0006-8950
VL - 140
SP - 1757
EP - 1767
JO - Brain
JF - Brain
IS - 6
ER -