Photodynamic diagnosis (PDD) using 5-aminolevulinic acid-supplemented cultures of human endometrial epithelial cells

The studies were aimed at monitoring 5-aminolevulinic acid (5-ALA)-dependent accumulation of endogenous protoporphyrin IX (PpIX) in epithelial cells originating from normal endometrium or endometriotic foci, as related to steroid treatment.

Epithelial cells were cultured in presence of estradiol-17 beta (E2) and progesterone (P) in concentrations typical for the follicular stage (E2 alone, 220 pg/ml) or the luteal stage (E2 100 pg/ml and P 2 ng/ml) or in presence of progesterone alone (2 ng/ml) for a period of 24, 48 or 72 h. Effect of 5-ALA concentration on the accumulation of PpIX was defined in the cells incubated with 2.0 mmol/l 5-ALA for 2 h. PpIX fluorescence was detected using a confocal microscope.

After hormonal stimulation, intensity of PpIX-specific fluorescence was only slightly increased in epithelial cells originating from normal endometrium. Cultures of epithelial cells from endometriosis foci showed higher concentration of PpIX than did the cells originating from normal endometrium. The highest peak of PpIX fluorescence was noted in epithelial endometriotic cells after 48h incubation with progesterone.

The data on PpIX accumulation in epithelial cells in the presence of estradiol-17 beta or progesterone may provide indications as to the menstrual cycle phase(s) in which photodynamic therapy for endometriosis should be performed. It is concluded that hormonal condition of female body must be taken into account for diagnosis and treatment of endometriosis.