Watching death glow in real time

Researchers at the UCL Institute of Opthalmology describe in Nature their novel use of fluorescent proteins to monitor nerve cell death in real time. All neurodegenerative disorders involve nerve cell death at some point in their pathology. Research into the molecular events underlying apoptosis and necrosis has advanced significantly, with many elements and triggers recognized as common between difference neurodegenerative disorders. However, research investigating the progression and dynamics of disorders has relied upon histological or in vitro analysis, limiting the types of results obtainable.

Happily for the advancement of knowledge, the UCL group has tagged two cell death markers with fluorescent labels, allowing in vivo imaging of disease progression in live cultures cells. The two markers in question are annexin V and propidium iodide (PI), which have been previously established as a method for differentiating between apoptosis and necrosis (presumably in histological sections).

The UCL groups paper in Cell Disease and Death details their use of fluorescent-labelled annexin V and PI to image retinal ganglion cell apoptosis in the mammalian eye. They report that they were able to track changes to individual neurons over hours, days, and week. All together, sounds like another win in the fluorescent protein column.

Oddly, the conclusion of the paper states that the reported imaging could be useful in a clinical setting.

"Although the equipment we use in these studies has been customised to suit animal models, the instruments are essentially the same as those used in hospitals and clinics around the world. This raises the possibility that in the near future, clinicians may be able to assess retinal nerve cell death in vivo as a method of monitoring disease progression and treatment efficacy."

With an experimental procedure that requires the injection of fluorescent labeled proteins, I will be very curious to see how (and if) the technique transitions from rats and mice to humans.

Cordeiro MF et al. Imaging multiple phases of neurodegeneration: a novel approach to assessing cell death in vivo. Cell Death and Disease: 1, e3 (2010)


Astra Bryant

Astra Bryant is a graduate of the Stanford Neuroscience PhD program in the labs of Drs. Eric Knudsen and John Huguenard. She used in vitro slice electrophysiology to study the cellular and synaptic mechanisms linking cholinergic signaling and gamma oscillations – two processes critical for the control of gaze and attention, which are disrupted in many psychiatric disorders. She is a senior editor and the webmaster of the NeuWrite West Neuroblog