Lutetium texaphyrin (Lu-Tex): a potential new agent for ocular fundus angiography and photodynamic therapy.
OBJECTIVE
To investigate the suitability of lutetium texaphyrin (lu-tex) as a fluorescence imaging agent in the delineation of retinal vascular and choroidal vascular diseases. The utilization of an efficient fluorescent molecule that is also a photosensitizer represents a unique opportunity to couple diagnosis and therapy.


METHODS
Fundus fluorescence angiography comparing lu-tex (motexafin lutetium, Optrin, Pharmacyclics Inc, Sunnyvale, California) with the conventional angiographic dyes, sodium fluorescein, and indocynanine green (ICG), was performed on the eyes of normal and laser-injured New Zealand white rabbits. Plasma pharmacokinetic data and plasma protein binding were assessed in addition to light microscopy of the retina in both imaged and laser-injured eyes.


RESULTS
Normal retinal and choroidal vasculature was well delineated by lu-tex angiography. Experimentally induced choroidal and retinal vascular lesions were enhanced by lu-tex and demonstrated different staining patterns than fluorescein or ICG, particularly at the margins of the lesions. Lu-tex cleared rapidly from the plasma, with 39.7% bound to the high-density lipoprotein (HDL) fraction while 15.8% was bound to the low-density lipoprotein (LDL) fraction. No evidence of retinal toxicity after dye administration was observed by either ophthalmoscopy and fundus photography or by light microscopy.


CONCLUSIONS
Lu-tex angiography is a potentially valuable method for retinal vascular and choroidal vascular evaluation, and it has advantages over fluorescein and ICG angiography. The same agent could conceivably be used for both the identification of abnormal vasculature and subsequent photodynamic treatment.
Blumenkranz
M S
MS
Pharmacyclics Inc, Sunnyvale, CA, USA. mu.msb@forsythe.stanford.edu
Woodburn
K W
KW
Qing
F
F
Verdooner
S
S
Kessel
D
D
Miller
R
R
D000818:Animals; D002829:Choroid / Q000098:blood supply / Q000378:metabolism / Q000473:pathology; D020256:Choroidal Neovascularization / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D019793:Fluorescein; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D007208:Indocyanine Green; D008187:Lutetium / Q000493:pharmacokinetics / Q000627:therapeutic use; D008297:Male; D008665:Metalloporphyrins / Q000493:pharmacokinetics / Q000627:therapeutic use; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000493:pharmacokinetics / Q000627:therapeutic use; D011817:Rabbits; D015861:Retinal Neovascularization / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D012171:Retinal Vessels / Q000378:metabolism / Q000473:pathology
D008665:Metalloporphyrins; D017319:Photosensitizing Agents; C102825:motexafin lutetium; D008187:Lutetium; C437683:motexafin gadolinium; D007208:Indocyanine Green; D019793:Fluorescein