Diabetic Macular Edema (DME)
DME is the main cause of vision loss in working-age adults
in the U.S. It develops when breakdown of the
blood-retinal barrier allows fluid and other plasma components, to leak from
blood vessels into the retina.
Blood-retinal barrier breakdown, detected as increased retinal
vascular permeability, is observed very early in the diabetic retina
before any other retinopathic changes.
The greater the amount of retinal vascular permeability, the greater the
chance of progression to DME and vision loss.
Current clinical thinking identifies increased retinal vascular
permeability as critical to the pathophysiology of DME.
An estimated 1 to 2 million individuals in the U.S. have
DME, and another 6 to 9 million worldwide, numbers that are expected to grow as
the incidence of diabetes increases globally.
Current treatment approaches are dominated by invasive procedures: laser
photocoagulation, and off-label intravitreal injection of corticosteroids and
anti-VEGF agents. None of these
treatments are fully effective.
Importantly, none of these treatments are used prior to the occurrence
of significant vision loss, owing to their invasive nature. No pharmaceutical therapy is currently
approved for DME.
Hemorrhagic Stroke (ICH)
An intracerebral hemorrhage (ICH) is a deadly
and disabling cerebrovascular event caused by bleeding into the brain. It is estimated that up to 10% of all strokes in the U.S. result from a spontaneous ICH. The one-month fatality rate is 25-35%, with high incidence of disability amongst the survivors. High blood pressure and high blood glucose measured on admission are predictors of hematoma expansion and poor outcome. There are no pharmaceutical treatments.
Plasma Kallikrein in DME & ICH
Recent studies
carried out by ActiveSite and its' collaborators demonstrate that
hyperglycemia-induced cerebral hematoma expansion is mediated by the vascular serine protease plasma
kallikrein, and that plasma kallikrein also mediates retinal vascular dysfunction and causes retinal thickening in diabetic rats. These studies also show that ASP-440, a novel prototype plasma kallikrein inhibitor developed by ActiveSite, strongly suppressed both hyperglycemia-induced hematoma expansion, and diabetes-induced retinal vascular permeability. ActiveSite's small molecule plasma kallikrein inhibitors may provide a new therapeutic approach to these two diseases.
|