A novel potential application for 99mTc-HMPAO: endothelial cell labeling for in vitro investigation of cell-biomaterial interactions.
Good adherence of endothelial cells (ECs) seeded on vascular prostheses and cell retention under flow conditions are important factors to consider in the use of functionalized prostheses in vascular surgery. Because 111In-oxine radiolabeling presents disadvantages, we wondered whether, because of its well-known physical properties, 99mTc-hexamethyl propyleneamine oxime (HMPAO or exametazime) could be used.


METHODS
The cytotoxicity of unlabeled HMPAO and 99mTc-HMPAO at increasing concentrations and activities was tested on monolayers of the EC line EA-hy-926. The influence of temperature and time on tracer incorporation into cells was also tested. The optimal labeling conditions were applied to evaluate the retention of ECs seeded on polyester grafts under flow conditions by gamma camera detection.


RESULTS
The activity of 10 MBq/10(6) cells corresponding to 4.5 microg/10(6) cells of unlabeled HMPAO, applied for 3 h at 37 degrees C (cellular uptake = 18%), was the best compromise between the maintenance of cell viability and metabolic activity and efficient detection by the gamma camera. Spontaneous leakage was observed and analyzed by high-performance liquid chromatography. A cell loss of 13% after 180-min exposure to shear stress was obtained.


CONCLUSIONS
Our data thus indicate the feasibility of using such a radiolabeling technique to investigate EC-biomaterial interactions.
Fernandez
P
P
Laboratoire de Biophysique, Université Victor Ségalen Bordeaux 2, France.
Bordenave
L
L
Celerier
C
C
Bareille
R
R
Brouillaud
B
B
Basse-Cathalinat
B
B
D001807:Blood Vessel Prosthesis; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D004727:Endothelium / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D006801:Humans; D009499:Neutral Red; D010091:Oximes / Q000494:pharmacology; D011849:Radioactive Tracers; D019275:Radiopharmaceuticals / Q000494:pharmacology; D019690:Technetium Tc 99m Exametazime / Q000032:analysis / Q000494:pharmacology; D013997:Time Factors
D010091:Oximes; D011849:Radioactive Tracers; D019275:Radiopharmaceuticals; C068296:hexamethylpropyleneamine oxime; D009499:Neutral Red; D019690:Technetium Tc 99m Exametazime