Rat reproductive performance following photodynamic therapy with topically administered Photofrin

Applications of Photodynamic Therapy in Endometrial Diseases

Photodynamic therapy (PDT) is a medical procedure useful for several benign conditions (such as wound healing and infections) and cancer. PDT is minimally invasive, presents few side effects, good scaring, and is able to minimal tissue destruction maintaining organ anatomy and function. Endoscopic access to the uterus puts PDT in the spotlight for endometrial disease treatment. This work systematically reviews the current evidence of PDT’s potential and usefulness in endometrial diseases. Thus, this narrative review focused on PDT applications for endometrial disease, including reports regarding in vitro, ex vivo, animal, and clinical studies. Cell lines and primary samples were used as in vitro models of cancer, adenomyosis and endometrioses, while most animal studies focused the PDT outcomes on endometrial ablation. A few clinical attempts are known using PDT for endometrial ablation and cancer lesions. This review emphasises PDT as a promising field of research. This therapeutic approach has the potential to become an effective conservative treatment method for endometrial benign and malignant lesions. Further investigations with improved photosensitisers are highly expected.

Photodynamic detection of diseased axillary sentinel lymph node after oral application of aminolevulinic acid in patients with breast cancer

Benign as well as malignant tumour tissues of the breast demonstrate higher fluorescence intensity (FI) than normal breast tissue after application of a photosensitiser. As a follow-up study, we evaluated the FI of metastatic sentinel lymph nodes and metastatic axillary lymph nodes compared to nonmetastatic sentinel and axillary lymph nodes in patients with breast cancer. In all, 11 patients received 30 mg 5-aminolevulinic acid (ALA) kg(-1) bodyweight orally 3 h prior to surgery. The sentinel lymph node was marked with Nanocoll preoperatively and with a blue dye intraoperatively. Tumour excision, excision of the sentinel lymph node and an axillary lymph node dissection were performed during the same surgical session. The operation site was illuminated with blue light (400 nm) to obtain macroscopic tissue characterisation of fluorescence. Tissue samples were stored protected from light, and analysed using a fluorescence microscope. Results were correlated with histopathology. In all, 14 sentinel lymph nodes, seven axillary lymph nodes and seven primary tumours were analysed. Metastatic sentinel lymph nodes demonstrated a statistically significant higher FI than nonmetastatic sentinel lymph nodes (2630 vs 526, P<0.0001). The FI of metastatic sentinel lymph nodes, of metastatic axillary lymph nodes and of the primary tumour were comparably high, and were statistically significantly higher compared to the normal mammary tissue. Intraoperatively, only in a few cases, it was possible to recognise the metastatic sentinel lymph node macroscopically with blue light. Our study indicates that photodynamic diagnosis with ALA has a potential in the diagnosis and detection of the sentinel lymph node in patients with breast cancer, and is worth to be further investigated and developed for intraoperative photodynamic diagnosis and possibly therapy.

Photodynamic therapy in dermatology

The combination of light and chemicals to treat skin diseases is widely practiced in dermatology. Within this broad use of light and drugs, in recent years the concept of photodynamic therapy (PDT) has emerged. PDT is a promising modality for the management of various tumors and nonmalignant diseases, based on the combination of a photosensitizer that is selectively localized in the target tissue and illumination of the lesion with visible light, resulting in photodamage and subsequent cell death. Moreover, the fluorescence of photosensitizing compounds is also utilized as a helpful diagnostic tool for the detection of neoplastic tissue. Intensive basic and clinical research culminated in the worldwide approval of PDT for bladder, esophageal, and lung cancer. The expanding use of this relatively new therapeutic modality in dermatology at many centers around the world has revealed its efficacy for the treatment of cutaneous precancer and cancer, as well as selected benign skin disorders. The following article summarizes the main principles of PDT considering the most recent developments and provides a comprehensive synopsis of the present status of the use of PDT in dermatology. (J Am Acad Dermatol 2000;42:389-413.)

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be able to describe the basic concepts of PDT, including fundamental knowledge of the most relevant photosensitizers, the light sources, the mechanisms involved in PDT-mediated cell destruction, as well as the indications and limitations of photodynamic treatment of skin diseases.

Uptake of the photosensitizer benzoporphyrin derivative in human endometrium after topical application in vivo

STUDY OBJECTIVE

To determine both the time leading to maximum endometrial drug uptake and distribution of the photosensitizer benzoporphyrin derivative-monoacid ring A (BPD-MA) after intrauterine instillation (Canadian Task Force classification ).

DESIGN

Assessment of histology specimens (Canadian Task Force classification I).

SETTING

University-based facility.

PATIENTS

Twenty-two women scheduled for hysterectomy.

INTERVENTIONS

We instilled 1.5 ml of a 2 mg/ml of BPD-MA-Hyskon solution into the uterine cavity of 22 women before hysterectomy. The fluorescence induced was measured by fluorescence microscopy on frozen sections of uterine samples from 20 of 22 patients. Systemic uptake of BPD-MA was determined in plasma of six patients by spectrofluorometry.

MEASUREMENTS AND MAIN RESULTS

The BPD-MA-induced fluorescence was maximum 1 hour after instillation, with significantly higher uptake in endometrial glands than in underlying stroma. Hormonal endometrial stimulation correlated with fluorescence intensity: atrophy < secretory phase < proliferative phase. Strongest fluorescence was seen in endometrial cancer. Drug uptake by endometrial glands was found at a depth of 2 mm from the surface. Systemic uptake of BPD-MA was under the detection level of 2 ng/ml after application.

CONCLUSION

Fluorescence in human endometrial glands suggests that selective destruction of human endometrium with photodynamic therapy may be possible 1 hour after topical application of BPD-MA for benign and malignant lesions. No systemic drug uptake, side effects, or major technical difficulties were detected. Limited penetration of the drug and selective uptake by endometrial glands provided a high degree of safety for endometrial ablation.

Selective photosensitizer localization in the human endometrium after intrauterine application of 5-aminolevulinic acid

OBJECTIVE

Our purpose was twofold: to determine the distribution of the endogenous photosensitizer protoporphyrin IX in the uterus and to ascertain the time interval leading to maximal endometrial fluorescence after intrauterine instillation of 5-aminolevulinic acid.

STUDY DESIGN

One milliliter of a 400 mg/ml 5-aminolevulinic acid-Hyskon solution was instilled into the uterine cavity of 27 women before hysterectomy. On frozen sections of uterine samples 5-aminolevulinic acid-induced fluorescence was measured with fluorescence microscopy.

RESULTS

5-Aminolevulinic acid-induced fluorescence could first be detected in the superficial endometrial glands 75 minutes after drug injection. In the endometrial gland stumps fluorescence intensity peaked 4 to 8 hours after 5-aminolevulinic acid instillation and was > 48 times higher than in the underlying myometrium.

CONCLUSIONS

Fluorescence in the endometrial glands suggests that selective photodynamic destruction of the endometrium may be possible 4 to 8 hours after intrauterine 5-aminolevulinic acid instillation.

Photodynamic therapy of rat endometrium sensitized with tin ethyl etiopurpurin

STUDY OBJECTIVE

To evaluate endometrial ablation in the rat using photodynamic therapy and the photosensitizer tin ethyl etiopurpurin (SnET2).

DESIGN

Laboratory research.

SETTING

A pharmaceutical and device manufacturing company.

MATERIALS

Forty-five healthy female rats (age 8-10 wks).

INTERVENTIONS

Groups of three to five rats were given SnET2 by either intrauterine or intravenous administration. Light treatment was given at either 3 or 24 hours after SnET2 administration at a light dose of 75, 150, or 200 J/cm.

MEASUREMENTS AND MAIN RESULTS

A fluorescence detection system was employed to determine relative drug uptake of SnET2 into uterine tissue. The highest levels of SnET2 were detected at 3 hours. After light treatment, responses of uterine tissues were evaluated histologically. The best endometrial ablation was seen when SnET2 was given by intrauterine administration with light treatment at 150 J/cm 24 hours later. A consistent transmural response was seen with this route of administration at 200 J/cm. Intravenous SnET2 gave inconsistent responses. In light-only controls, all light doses caused no tissue response. The depth of necrosis in tissues treated with photodynamic therapy were light-dose dependent.

CONCLUSION

With either route of SnET2 administration, drug uptake was confirmed and a light-dose-dependent response in the walls of rat uterine horns was demonstrated.

Structural and functional effects of endometrial photodynamic therapy in a rat model

OBJECTIVE

Our purpose was to determine the optical dose required for irreversible endometrial destruction and prevention of implantation by photodynamic therapy with topical 5-aminolevulinic acid.

STUDY DESIGN

Three hours after drug application 74 female Sprague-Dawley rats received varying doses of 630 nm of light delivered by an intrauterine cylindric diffusing fiber.

RESULTS

A 64 J/cm2 in situ optical dose resulted in long-term irreversible endometrial destruction; 43 J/cm2 damaged endometrial stroma and myometrium but not glandular epithelium 1 day after photodynamic therapy. At this lower light dose endometrium regenerated to full thickness within 3 weeks; however, implantation sacs were significantly reduced.

CONCLUSIONS

Photodynamic destruction of glandular epithelium accompanies irreversible endometrial ablation, whereas isolated stromal damage leads to reproductive impairment only. The optical dose required for endometrial ablation is approximately 1.5-fold higher than for reproductive impairment (functional damage) because of differential cell photosensitivity.

A mathematical model for light dosimetry in photodynamic destruction of human endometrium

We are involved in the development of photodynamic therapy (PDT) as a minimally invasive method for treating dysfunctional uterine bleeding, one of the primary clinical indications for hysterectomy. In this paper, we analyse light propagation through the uterus in order to specify the requirements for a light delivery system capable of effectively performing endometrial PDT. Our approach involves developing an analytical model based on diffusion theory to predict optical fluence rate distributions when cylindrical and spherical optical applicators are placed in the uterine cavity. We apply the results of our model calculations to estimate the thermal effects of optical irradiation and the effective photodynamic optical dose. Theoretical fluence rate calculations are compared to fluence rate measurements made in fresh, surgically removed human uteri. Our results show that a trifurcated cylindrical optical applicator inserted into the human uterus can provide a light dose that is sufficient to cause photodynamic destruction of the entire endometrium. When the optical power per unit length of each cylindrical applicator is 100 mW cm-1 (at 630 nm), a fluence rate of 40 mW cm-2 is delivered to the boundary layer between the endometrium and the myometrium (a depth of about 4-6 mm). The optical fluence delivered to the boundary layer after 20 min of exposure is 50 J cm-2, a level that is generally accepted to cause tissue damage throughout the endometrium in most patients.

TNF-α induces dyscohesion of epithelial cells. Association with disassembly of actin filaments

TNF-α induced, in a time and dose-dependent fashion, cell-cell dissociation (dyscohesion) of endometrial epithelial cells. Within the time frame that dyscohesion was induced, TNF-α, in a dose-dependent fashion, reduced filamentous (F) actin and resulted in the loss of F-actin from the intercellular boundaries. Loss of F-actin mediated by TNF-α was not due to a reduction in the overall amount of actin or its β-isoform. Two proteins, Rho and Rho guanine nucleotide dissociation inhibitor (Rho-GDI), have been implicated in the regulation of organization of actin cytoskeleton. The reduced level of F-actin was not associated with altered expression of Rho protein, however, it was associated with an increase in the amount of Rho available for ribosylationin vitro by the C3 exoenzyme of Clostridium botulinum. The amount of Rho-GDI protein did not change after treatment with TNF-α suggesting that elevated expression of this protein is not responsible for the disassembly of actin filaments. These findings show that TNF-α induces dyscohesion. Dyscohesion induced by this cytokine is associated with perturbation of the actin cytoskeleton which may be due to the regulatory role of TNF-α on Rho.