5-aminolevulinic acid-mediated photodynamic therapy of intraepithelial neoplasia and human papillomavirus of the uterine cervix--a new experimental approach

Long-term follow-up of photodynamic therapy of cervical intraepithelial neoplasia grade 2 (CIN2)

BACKGROUND

To determine the long-term efficacy and safety of 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) for treating cervical intraepithelial neoplasia grade 2 (CIN2) as well as the suitability of ALA-PDT in treating of cervical lesions divided into cervical transformation zone type 3.

METHODS

We included 81 patients diagnosed with CIN2 at the Department of Gynecology of the Affiliated Hospital of Qingdao University with data collected between January 2019 and January 2021 following ALA-PDT. Furthermore, we analyzed the superiority of ALA-PDT in fertility preservation among women of childbearing age based on follow-up data from 11 patients with fertility requirements.

RESULTS

Our findings confirmed the long-term efficacy of ALA-PDT for CIN2 treatment, with an overall efficacy of 95.83 % (23/24) at follow-up of 25-36 months. Moreover, the cervical transformation zone type 3 improvement and human papillomavirus (HPV)-negative efficacy were 69.2 % (18/26) and 82.4 % (14/17), respectively. ALA-PDT is recommended for consenting patients with cervical transformation zone type 3. Additionally, women without primary infertility could experience natural pregnancy and full-term birth of more than one baby following ALA-PDT for CIN2 treatment, with a satisfaction rate of ≈100 %.

CONCLUSIONS

ALA-PDT is recommendable for treating high-grade squamous intraepithelial lesions, especially in patients with fertility requirements.

Evaluation of combination of ALA-PDT and interferon for cervical low-grade squamous intraepithelial lesion (LSIL)

BACKGROUND

Cervical LSIL is a precancerous disease which requires regular follow-up. High risk patients need active interventions. Interferon and topical PDT have been used in the treatment of cervical LSIL. The aim of this study was to evaluate the combination use of topical PDT and interferon in the treatment of cervical LSIL.

MATERIALS AND METHODS

A prospective study was carried out involving 159 women with cervical LSIL and high risk human papillomaviruses (hr-HPV) infection. Patients were divided into three groups. Group 1-receiving interferon suppository only, Group 2-receiving 19 mg/cm2 ALA plus post PDT interferon, and Group 3-receiving 38 mg/cm2 ALA plus post PDT interferon. The primary endpoint was pathological regression. The secondary endpoints were the HPV negative conversion rate and the adverse effects of treatment.

RESULTS

At 6-12 months after PDT, for Group 1, the effective rate, CR rate and HPV negative conversion rate was 48.3 %, 43.3 % and 24.0 %, respectively. For Group 2, the effective rate, CR rate and HPV negative conversion rate were 89.3 %, 71.4 %, and 72.4 %, respectively. For Group 3, the effective rate, CR rate and HPV negative conversion rate were 91.5 %, 66.1 %, and 64.4 %, respectively, significantly higher than those of interferon only group. Two ALA dose group study showed similar efficacy. No patient experienced serious adverse effects.

CONCLUSIONS

ALA-PDT combined with interferon therapy was feasible and tolerable. Two ALA dose groups showed similar outcomes in treating cervical LSIL.

A novel PDT: 5-aminolevulinic acid combined 450 nm blue laser photodynamic therapy significantly promotes cell death of HR-HPV infected cells

Human papillomavirus (HPV) infection and related diseases are clinical challenges. The efficacy of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) using red laser (630 ± 5 nm) is remarkable and safe. In this study, we aim to investigate the efficacy of ALA-450 nm PDT comparing with ALA-635 nm PDT. We detected cell proliferation and cell apoptosis through MTT assay and flow cytometry assay respectively. Flow cytometry assay determined the intracellular reactive oxygen species (ROS) generation. Western blotting analysis investigated the protein expression. In vivo, immunohistochemical staining assay and TUNEL assay were performer to detect cell apoptosis. ALA-450 nm PDT inhibited the proliferation of End1 and HeLa cells, promoted cell apoptosis more effectively than ALA-635 nm PDT, and induced cell death probably through increasing the intracellular ROS generation and caspase-dependent apoptosis pathway. In vivo, ALA-450 nm PDT significantly inhibited tumour growth and activated cell apoptosis. The ALA-450 nm PDT had an advantage over ALA-635 nm PDT on inhibiting the proliferation of End1 and HeLa cells and inducing cell apoptosis. The ALA-450 nm PDT might be a promising therapeutic strategy for eradicating the HR-HPV infected cells and promoting the integration of diagnosis and treatment of HR-HPV related diseases.HighlightsWe combined 5-aminolevulinic acid with 450 nm blue laser using as a novel type of photodynamic therapy.The ALA-450 nm PDT had an advantage over ALA-635 nm PDT on inhibition of the proliferation of End1 and HeLa cells and inducing cell apoptosis in vitro and in vivo.The ALA-450 nm PDT may provide a novel alternative therapeutic option in patients with persistent HPV infection and promote the integration of diagnosis and treatment.

CD44 Receptor-Mediated/Reactive Oxygen Species-Sensitive Delivery of Nanophotosensitizers against Cervical Cancer Cells

Stimulus-sensitive, nanomedicine-based photosensitizer delivery has an opportunity to target tumor tissues since oxidative stress and the expression of molecular proteins, such as CD44 receptors, are elevated in the tumor microenvironment. The aim of this study is to investigate the CD44 receptor- and reactive oxygen species (ROS)-sensitive delivery of nanophotosensitizers of chlorin e6 (Ce6)-conjugated hyaluronic acid (HA) against HeLa human cervical cancer cells. For the synthesis of nanophotosensitizers, thioketal diamine was conjugated with the carboxyl group in HA and then the amine end group of HA-thioketal amine conjugates was conjugated again with Ce6 (Abbreviated as HAthCe6). The HAthCe6 nanophotosensitizers were of small diameter, with sizes less than 200. Their morphology was round-shaped in the observations using a transmission electron microscope (TEM). The HAthCe6 nanophotosensitizers responded to oxidative stress-induced changes in size distribution when H₂O₂ was added to the nanophotosensitizer aqueous solution, i.e., their monomodal distribution pattern at 0 mM H₂O₂ was changed to dual- and/or multi-modal distribution patterns at higher concentrations of H₂O₂. Furthermore, the oxidative stress induced by the H₂O₂ addition contributed to the disintegration of HAthCe6 nanophotosensitizers in morphology, and this phenomenon accelerated the release rate of Ce6 from nanophotosensitizers. In a cell culture study using HeLa cells, nanophotosensitizers increased Ce6 uptake ratio, ROS generation and PDT efficacy compared to free Ce6. Since HA specifically bonds with the CD44 receptor of cancer cells, the pretreatment of free HA against HeLa cells decreased the Ce6 uptake ratio, ROS generation and PDT efficacy of HAthCe6 nanophotosensitizers. These results indicated that intracellular delivery of HAthCe6 nanophotosensitizers can be controlled by the CD44 receptor-mediated pathway. Furthermore, these phenomena induced CD44 receptor-controllable ROS generation and PDT efficacy by HAthCe6 nanophotosensitizers. During in vivo tumor imaging using HeLa cells, nanophotosensitizer administration showed that the fluorescence intensity of tumor tissues was relatively higher than that of other organs. When free HA was pretreated, the fluorescence intensity of tumor tissue was relatively lower than those of other organs, indicating that HAthCe6 nanophotosensitizers have CD44 receptor sensitivity and that they can be delivered by receptor-specific manner. We suggest that HAthCe6 nanophotosensitizers are promising candidates for PDT in cervical cancer.

Reactive Oxygen Species-Sensitive Nanophotosensitizers of Methoxy Poly(ethylene glycol)-Chlorin e6/Phenyl Boronic Acid Pinacol Ester Conjugates Having Diselenide Linkages for Photodynamic Therapy of Cervical Cancer Cells

The aim of this study is to fabricate nanophotosensitizers composed of methoxy poly(ethylene glycol) (mPEG), chlorin e6 (Ce6), and phenylboronic acid pinacol ester (PBAP) with diselenide linkages for reactive oxygen species (ROS)-sensitive photodynamic therapy (PDT) of cervical cancer cells. To fabricate nanophotosensitizers, Ce6 was conjugated with mPEG via selenocystamine linkage and then remaining carboxylic acid groups of Ce6 was attached to PBAP (mPEGseseCe6PBAP conjugates). Nanophotosensitizers of mPEGseseCe6PBAP conjugates were prepared by dialysis method. In transmission electron microscope (TEM) observation, nanophotosensitizers of mPEGseseCe6PBAP conjugates have spherical shapes and their diameters were less than 150 nm. The average diameter of mPEGseseCe6PBAP nanophotosensitizers was 92.7 ± 9.6 nm in particle size analysis. When H₂O₂ was added to the nanophotosensitizer solution, nanophotosensitizers were sensitively disintegrated according to the H₂O₂ concentration and then changed from monomodal distribution to multimodal distribution in particle size distribution. Furthermore, Ce6 release from nanophotosensitizers also increased according to the H₂O₂ concentration. When H₂O₂ was added to cell culture of HeLa human cervical cancer cells, intracellular Ce6 uptake of nanophotosensitizers were gradually increased according to the H₂O₂ concentration, indicating that nanophotosensitizers showed ROS-sensitive delivery of Ce6 against cancer cells.As well as free Ce6, nanophotosensitizers in the absence of light irradiation have low intrinsic cytotoxicity against RAW264.7 cells and HeLa cells. However, nanophotosensitizers induced cell death dose-dependently under light irradiation. Especially, nanophotosensitizers showed significantly higher ROS generation and phototoxicity against HeLa cells in vitro. When nanophotosensitizers were intravenously administered to animal tumor xenograft model of HeLa cells, tumor tissues revealed stronger fluorescence intensity than other tissues by light irradiation while absence of light irradiation induced relatively lower fluorescence intensity in tumor tissues, indicating that nanophotosensitizers have sensitivity against oxidative stress in tumor tissues. We suggest that nanophotosensitizers of mPEGseseCe6PBAP conjugates are promising vehicle for PDT of cervical cancer cells.

Redox-Sensitive and Folate-Receptor-Mediated Targeting of Cervical Cancer Cells for Photodynamic Therapy Using Nanophotosensitizers Composed of Chlorin e6-Conjugated β-Cyclodextrin via Diselenide Linkage

The aim of this study was to fabricate a reactive oxygen species (ROS)-sensitive and folate-receptor-targeted nanophotosensitizer for the efficient photodynamic therapy (PDT) of cervical carcinoma cells. Chlorin e6 (Ce6) as a model photosensitizer was conjugated with succinyl β-cyclodextrin via selenocystamine linkages. Folic acid (FA)-poly(ethylene glycol) (PEG) (FA-PEG) conjugates were attached to these conjugates and then FA-PEG-succinyl β-cyclodextrin-selenocystamine-Ce6 (FAPEGbCDseseCe6) conjugates were synthesized. Nanophotosensitizers of FaPEGbCDseseCe6 conjugates were fabricated using dialysis membrane. Nanophotosensitizers showed spherical shapes with small particle sizes. They were disintegrated in the presence of hydrogen peroxide (H₂O₂) and particle size distribution changed from monomodal distribution pattern to multimodal pattern. The fluorescence intensity and Ce6 release rate also increased due to the increase in H₂O₂ concentration, indicating that the nanophotosensitizers displayed ROS sensitivity. The Ce6 uptake ratio, ROS generation and cell cytotoxicity of the nanophotosensitizers were significantly higher than those of the Ce6 itself against HeLa cells in vitro. Furthermore, the nanophotosensitizers showed folate-receptor-specific delivery capacity and phototoxicity. The intracellular delivery of nanophotosensitizers was inhibited by folate receptor blocking, indicating that they have folate-receptor specificity in vitro and in vivo. Nanophotosensitizers showed higher efficiency in inhibition of tumor growth of HeLa cells in vivo compared to Ce6 alone. These results show that nanophotosensitizers of FaPEGbCDseseCe6 conjugates are promising candidates as PDT of cervical cancer.

Clinical treatment of intra-epithelia cervical neoplasia with photodynamic therapy

OBJECTIVES

This clinical study was developed to primarily evaluate the Complete Cytopathological Response Rate of Cervical Intraepithelial Neoplasms to PDT using chitosan nanocapsules containing Chlorocyan-aluminum phthalocyanine as a photoactive agent. Analyses of the Free Recurrence Interval, toxicity profile (immediate and late), and complications (immediate and late), were secondarily analyzed.

METHODS

This study was previously approved by the National Council of Ethics in Research of Brazil (CONEP), on May 28, 2014, under case number 19182113.4.0000.5009. On the surface of the cervix of each selected patient was applied one mL of the formulated gel, and after 30 min, the light was applied. Reports or the identification of adverse effects and/or complications were observed in follow-up visits, in addition to the collection of cervical oncotic cytology.

RESULTS

Out of the total group, 11 (91.7%) primarily treated patients evolved with negative cervical oncotic cytology as soon as in the first evaluation following treatment, and one did not achieve any therapeutic benefit, even after reapplication. Two patients with initially positive response presented cytological recurrence determined by histopathology. A new round of PDT was developed, and both evolved with cytological remission three weeks later, remaining negative until the last follow-up. No important side effects were observed in all the patients.

CONCLUSIONS

Our trial demonstrates that treatment of CIN 1 and 2 lesions using our PDT formulation is feasible and safe. Large randomized clinical trials are required to establish efficacy.

Photodetection and Safety of 5-Aminolevulinic Acid-Induced Porphyrin in Patients With Cervical Intraepithelial Neoplasia

BACKGROUND AND OBJECTIVES

5-Aminolevulinic acid (5-ALA) is a porphyrin-based photosensitizer and has been used for photodynamic therapy of cervical intraepithelial neoplasia (CIN). In this study, photodetection and safety of 5-ALA-induced porphyrin in CIN tissues were assessed.

STUDY DESIGN/MATERIALS AND METHODS

A total of 42 patients for whom colposcopy or loop electrosurgical excision procedure (LEEP) was planned were administered 10%, 20%, or 30% 5-ALA locally on the surface of the cervix for 1.5-18 hours. At different times after application, the fluorescence intensity of 5-ALA-induced porphyrin on CIN and non-CIN lesions of the cervix was detected.

RESULTS

Fluorescence intensity was correlated with drug concentration and application time. With 20% 5-ALA, the porphyrin fluorescence intensity increased over time, reaching a peak after 6 hours of application intervals in CIN. There was no significant difference in fluorescence intensity between CIN lesions and chronic cervicitis (benign tissue) or among CIN lesions of different severities. Three adverse events were considered related to the drug; however, these had no significant correlation with the drug concentration or application time.

CONCLUSIONS

5-ALA at 10%-30% concentration is safe in patients with CIN. For further treatment, we recommend the application of 20% 5-ALA, 6 hours before photodynamic therapy in CIN.

CLINICAL TRIAL REGISTRATION

This study was registered at http://www.chinadrugtrials.org.cn (registration number: CTR20130326) in accordance with the requirements of the National Medical Products Administration in China. Considering that there is no English version of the above website, we made a retrospective registration on http://www.chictr.org.cn (registration number ChiCTR1800016755) in 2018. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Efficacy of 5-aminolevulinic acid and LED photodynamic therapy in cervical intraepithelial neoplasia: A clinical trial

BACKGROUND

5-Aminolaevulinic acid (5ALA) is a precursor of the strong sensitizer protoporphyrin IX (PpIX) in the heme synthesis pathway. We conducted aclinical trial designed to evaluate the efficacy and safety of 5ALA photodynamic therapy (PDT) using a light-emitting diode (LED) in patients with cervical intraepithelial neoplasia (CIN).

METHODS

Data for 51 CIN patients who underwent 5ALA-PDT between 2012 and 2017 were prospectively analysed. After a 20 % 5ALA jelly formulation was topically applied to the cervix, the region was irradiated with red light at approximately 633 nm to excite PpIX for treatment. We estimated outcomes by cytology, pathology, and human papilloma virus (HPV) testing after PDT.

RESULTS

Patients underwent two PDT sessions at one-week intervals during outpatient treatment and achieved favourable results without photosensitivity and severe adverse events. Over a long follow-up period, 96.1 % of all patients showed some positive effects, including approximately 70 % with a complete response (CR), 10 % with a partial response, and 15 % with downgrades. The HPV clearance rate in patients with CR was 79.4 %. Recurrence occurred in five patients who mostly remained HPV-positive after PDT.

CONCLUSIONS

Based on our study, topical 5ALA-PDT using an LED light source potentially represents a safe treatment for CIN on an outpatient basis.

Efficacy and safety of photodynamic therapy for cervical intraepithelial neoplasia and human papilloma virus infection: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

We sought to conduct a systemic review and meta-analysis of randomized clinical trials to assess the efficacy and safety of photodynamic therapy (PDT) in cervical intraepithelial neoplasia (CIN) and cervical human papilloma virus (HPV) infection.

METHODS

The Medline, EMBASE, and Cochrane Central Register databases were searched using relevant keywords for entries up to May 1, 2017, irrespective of year of publication. The language was restricted to English. Randomized clinical trials and qualitative studies comparing PDT and placebo for CIN or HPV-positive patients were included. We assessed the evidence quality using a risk of bias graph in RevMan V5.3 and the Grading of Recommendations Assessment, Development, and Evaluation scoring system.

RESULTS

Of the 168 studies identified, only 4 RCTs met the inclusion criteria for meta-analysis. In all, 292 and 141 patients received PDT or placebo, respectively. PDT significantly increased the complete remission rate (CRR) among those with CIN (odds ratio [OR]: 2.51 [1.23-5.12]; P = .01) and HPV infection (OR: 3.82 [1.91-7.65]; P = .0002). The adverse events rate (AER) for PDT was greater than that for placebo (OR: 13.32 [4.44, 40.02]; P < .00001). The overall evidence quality was very low. Similarly, in a systematic review including 21 qualitative records, the CRRs for CIN patients with PDT and cervical HPV infection patients with PDT were 82.0% and 77.5%, respectively. The AER for PDT was 31.6%, which was lower than that observed in our meta-analysis (74.6%).

CONCLUSIONS

PDT that targets CIN or cervical HPV infection improves the CRR, but slightly compromises safety. Further studies are necessary to identify the most effective and least toxic photosensitizer.

Efficacy and safety of hexaminolevulinate photodynamic therapy in patients with low-grade cervical intraepithelial neoplasia

OBJECTIVE

Non-surgical therapies are needed to reduce the rate of progression of low-grade cervical intraepithelial neoplasia (CIN 1) to high grade CIN (CIN 2/3). The aim of this study was to assess the efficacy and safety of hexaminolevulinate (HAL) photodynamic therapy (PDT) in the treatment of patients with CIN 1.

STUDY DESIGN

This phase IIa prospective double-blind study randomized patients with CIN 1 into three groups: HAL vaginal suppository, placebo vaginal suppository or follow-up only. Patients in the first two groups received HAL or placebo suppositories 5 hours before illumination with 50 J/cm(2) red coherent light (633 nm) using a special light catheter. All patients had a follow up including colposcopy, cytology and human papilloma virus (HPV) testing 3 and 6 months and additional biopsy 6 months after PDT. The main outcome measure was efficacy, defined as complete histologic remission 6 months after PDT. Secondary outcomes were histologic remission 3 months and HPV eradication 6 months after first PDT.

RESULTS

Seventy patients were randomized: 47 to HAL, 12 to placebo, 11 to follow up only. After 6 months CIN lesions had cleared in 57% of patients in the HAL-PDT group compared to 25% in the combined control group (per protocol population, P = 0.04). Twenty-six patients (37%) reported 44 adverse events (AEs), of which 40 were mild or moderate. Nineteen treatment-related AEs were reported by 15 patients (32%) in the HAL PDT group, one in the placebo PDT group (8%), and none in the follow-up group. The most common adverse events were local discomfort including mild pain/cramping (11) and leucorrhoea (2).

CONCLUSION

HAL PDT shows a favorable efficacy and safety profile and represents a promising alternative to observation and surgical procedures in patients with CIN 1.

Efficacy and safety of photodynamic therapy for cervical intraepithelial neoplasia: a systemic review

BACKGROUND

The current treatment of cervical intraepithelial neoplasia (CIN) is primarily based on surgical excision using laser, a loop electrosurgical procedure, or a cold knife technique. Unfortunately, these treatments often lead to obstetrical problems during the subsequent pregnancy, particularly in young women. Photodynamic therapy (PDT), which uses a topical or intravenous photosensitizer (PS) activated by a light source to ablate abnormal tissue, offers a minimally invasive alternative. The purpose of this study was to comprehensively assess the effectiveness and safety of PDT in the treatment of CIN.

METHODS

Following Cochrane guidelines, a comprehensive systematic review of all clinical studies and reports examining the use of PDT for CIN was conducted. Study quality was assessed using the Oxford Levels of Evidence Scale.

RESULTS

The 14 studies included two randomized control trials (RCTs), one case-control study, and 11 case series. Among the 506 patients studied, 472 were included to study the effectiveness of PDT on CIN and 10 were lost to follow-up. An assessment of clinical effectiveness included the response of the lesion to treatment (may include lesion recurrence) reported by all 14 studies. The complete response rate (CRR) of PDT on CIN ranged from 0% to 100%. HPV eradication rate (HER) was reported in seven studies, with rates ranging from 53.4% to 80.0%.

CONCLUSIONS

PDT is a safe and tolerable treatment for CIN. Evidence regarding the efficacy of PDT for CIN is conflicting, which may, in part, be explained by the limited number of controlled comparative clinical trials.

Photodynamic therapy of cervical intraepithelial neoplasia 1-3 and human papilloma virus (HMV) infection with methylaminolevulinate and hexaminolevulinate--a double-blind, dose-finding study

INTRODUCTION

Cervical intraepithelial neoplasia (CIN) 1-3 is the precursor of invasive cervical cancer and associated with human papillomavirus infection. Standard treatment is surgical and may be associated with subsequent pregnancy complications. Photodynamic therapy (PDT) of CIN may be an interesting alternative.

MATERIAL AND METHODS

Patients were treated by PDT using hexaminolevulinate (HAL) and methylaminolevulinate in six dose and light groups and two incubation periods in a double-blind setting. Follow-up examinations were performed after 3, 6, and 12 months with histology, cytology, and HPV testing.

RESULTS

We included eight patients with CIN1, 23 with CIN2, and 36 with CIN3. Treatment was well tolerated. HAL 40 mM with 3-hour application turned out to be the most-effective group with 67% (10/15) complete response rate. The combined complete and partial response for patients with CIN2 was 83% (20/24).

CONCLUSION

PDT with CIN may be a safe and effective procedure for CIN treatment.

Photodynamic therapy for gynecological diseases and breast cancer

Photodynamic therapy (PDT) is a minimally invasive and promising new method in cancer treatment. Cytotoxic reactive oxygen species (ROS) are generated by the tissue-localized non-toxic sensitizer upon illumination and in the presence of oxygen. Thus, selective destruction of a targeted tumor may be achieved. Compared with traditional cancer treatment, PDI has advantages including higher selectivity and lower rate of toxicity. The high degree of selectivity of the proposed method was applied to cancer diagnosis using fluorescence. This article reviews previous studies done on PDT treatment and photodetection of cervical intraepithelial neoplasia, vulvar intraepithelial neoplasia, ovarian and breast cancer, and PDT application in treating non-cancer lesions. The article also highlights the clinical responses to PDT, and discusses the possibility of enhancing treatment efficacy by combination with immunotherapy and targeted therapy.

Screening of drugs to counteract human papillomavirus 16 E6 repression of E-cadherin expression

Persistent infections with certain high-risk human papillomavirus (HPV) types such as 16 and 18 can result in the development of cervical cancer. Neither of the two prophylactic vaccines against HPV16 and 18 that are in current use have any therapeutic efficacy for prevalent HPV infections. Ablative therapy is widely used for the treatment of HPV cervical dysplasia however disease recurrence is a widely recognized problem. Thus there is a continuing need for therapeutic approaches for the treatment of HPV infections. The HPV16 E6 viral oncoprotein represses surface expression of the cellular adhesion molecule, E-cadherin. Reduced E-cadherin expression on HPV-infected keratinocytes is associated with lowered numbers of antigen-presenting Langerhans cells in the infected epidermis, potentially reducing immune surveillance for HPV. Four chemicals reported to up-regulate E-cadherin were screened for their ability to counteract E6 repression of surface E-cadherin. 5-Aza-2'-deoxycytidine (AzaDC), a DNA methyltransferase inhibitor, and Indole-3-carbinol (I3C), reported to increase E-cadherin through a p21(Waf1/Cip1)-dependent mechanism, had low cytotoxicity and increased or restored E-cadherin expression and adhesive function in HPV16 E6 expressing HCT116 cells. Doxorubicin, also known to induce p21(Waf1/Cip1), increased E-cadherin in E6 expressing cells but had some associated cytotoxicity. Tamoxifen, which can restore adhesive function of surface E-cadherin, was ineffective in counteracting E6 repression of E-cadherin. AzaDC and I3C both show potential to restore antigen-presenting cells to HPV infected skin by antagonizing E6 repression of E-cadherin, thereby counteracting an important immune evasion mechanism of HPV16 and reinstating immune function at the infected site.

Photodynamic therapy based on 5-aminolevulinic acid and its use as an antimicrobial agent

Exogenous 5-aminolevulinic acid (ALA) is taken up directly by bacteria, yeasts, fungi, and some parasites, which then induces the accumulation of protoporphyrin IX (PPIX). Subsequent light irradiation of PPIX leads to the inactivation of these organisms via photodamage to their cellular structures. ALA uptake and light irradiation of PPIX produced by host cells leads to the inactivation of other parasites, along with some viruses, via the induction of an immune response. ALA-mediated PPIX production by host cells and light irradiation result in the inactivation of other viruses via either the induction of a host cell response or direct photodynamic attack on viral particles. This ALA-mediated production of light-activated PPIX has been extensively used as a form of photodynamic therapy (PDT) and has shown varying levels of efficacy in treating conditions that are associated with microbial infection, ranging from acne and verrucae to leishmaniasis and onychomycosis. However, for the treatment of some of these conditions by ALA-based PDT, the role of an antimicrobial effect has been disputed and in general, the mechanisms by which the technique inactivates microbes are not well understood. In this study, we review current understanding of the antimicrobial mechanisms used by ALA-based PDT and its role in the treatment of microbial infections along with its potential medical and nonmedical applications.

Photodynamic therapy for intraepithelial neoplasia of the lower genital tract

Photodynamic Diagnosis (PDD) and Therapy (PDT) are modern methods which are evaluated in different fields in gynaecology. PDT has been successfully evaluated in human papillomavirus-related (HPV) genital dysplasia like CIN and VIN. The aim of this review is to give an overview about current applications.

[Diagnosis of cervical squamous intraepithelial lesions by fluorescence imaging: clinical feasibility study]

OBJECTIVE

Fluorescence diagnosis is still undeveloped in gynaecology. In order to diagnose and localize squamous intraepithelial lesion (SIL) of the cervix, a new method improving the low specificity of colposcopy would be useful. The goal of this study was to assess the feasibility and safety of colposcopic fluorescence diagnosis of SIL after topically application of methyl aminolevulinate (MAL).

PATIENTS AND METHODS

Patients with histologic proved cervical intraepithelial neoplasia (CIN) and planned for loop electrosurgical excision procedure (LEEP) under general anesthesia were included in a prospective study. Before general anesthesia, a thick layer of MAL (Metvix-160 mg/mL cream) was applied on the cervix for 35-150 min. Fluorescent colposcopic inspection of the cervix was performed using a rigid 10-mm laparoscope inserted in the vaginal cavity and connected to D-light AF system (Karl Storz Endoskope, Tuttlingen Germany). In order to confirm neoplasic status, fluorescent foci underwent directed punch biopsy(ies).

RESULTS

Fourteen patients were included in the study. Colposcopic fluorescence imaging revealed red fluorescent foci in 71.4% of cases (10/14) (neoplasic status of fluorescent foci was confirmed in 80%). Concerning MAL, the mean of application time was 73 min (35-150). Two cases presented a false-positive fluorescence and four cases of false-negative fluorescence. For all cases of false-negative fluorescence, application time of MAL was less than 60 min. We observed no systemic or local toxicity of MAL application in any group.

DISCUSSION AND CONCLUSION

Using topical application of MAL to the cervix, we demonstrated that fluorescence diagnosis of SIL is feasible. This study justifies the further development of fluorescence imaging that combines classical white light colposcopy with the use of a photosensitizer.

Photodynamic therapy of cervical intraepithelial neoplasia with hexaminolevulinate

BACKGROUND AND OBJECTIVE

CIN is a disease of women in their reproductive years, and treatment includes excisional techniques with increased risk of preterm deliveries. Photodynamic therapy (PDT) using topical precursor of photoactive porphyrins may be a non-invasive alternative with minimal side effects. This study assessed the feasibility and response rate of PDT with hexaminolevulinate (HAL) in cervical intraepithelial neoplasia (CIN) and human papillomavirus (HPV) infection.

STUDY DESIGN/MATERIALS AND METHODS

Twenty four patients with a CIN 2 or 3 or a persistent CIN 1 and a positive high-risk HPV-DNA test were included. Each patient had gynaecologic examination including cervical cytology, HPV DNA testing, colposcopy and biopsy. Ten milliliters of HAL-thermogel (10 mM) were topically applied to the cervix for 3-5 hours, followed by 1,000 seconds of illumination of both ecto- and endocervical canal with red coherent light (wave length 633 nm) using a PDT laser and a special light catheter. Follow-up examinations were carried out after 3 (cytology, colposcopy, HPV DNA testing, and if needed re-PDT) and 6 months.

RESULTS

Seven, 10, and 7 patients had a CIN 1, 2, or 3, respectively. Treatment could be accomplished in all cases and no severe side effects were encountered. Fifteen out of the 24 patients had a complete response (15/24 = 63%) and a HPV remission 6 months after 1-3 treatments. The remission rates were 71%, 50%, and 71% for CIN 1, 2 and 3.

CONCLUSION

HAL PDT seems to be a non-invasive, repeatable procedure for CIN and cervical HPV infection with minimal side effects which can be easily performed on outpatient basis.

Photosensitiser delivery for photodynamic therapy. Part 1: Topical carrier platforms

BACKGROUND

Photodynamic therapy (PDT) is a medical treatment in which a combination of a photosensitising drug and visible light causes destruction of selected cells. Due to the lack of true selectivity of preformed photosensitisers for neoplastic tissue and their high molecular weights, PDT of superficial skin lesions has traditionally been mediated by topical application of the porphyrin precursor 5-aminolevulinic acid (ALA).

OBJECTIVE

This article aims to review the traditional formulation-based approaches taken to topical delivery of ALA and discusses the more innovative strategies investigated for enhancement of PDT mediated by topical application of ALA and preformed photosensitisers.

METHODS

All of the available published print and online literature in this area was reviewed. As drug delivery of agents used in PDT is still something of an emerging field, it was not necessary to go beyond literature from the last 30 years.

RESULTS/CONCLUSION

PDT of neoplastic skin lesions is currently based almost exclusively on topical application of simple semisolid dosage forms containing ALA or its methyl ester. Until expiry of patents on the current market-leading products, there is unlikely to be a great incentive to engage in design and evaluation of innovative formulations for topical PDT, especially those containing the more difficult-to-deliver preformed photosensitisers.

Thermosetting Gel for the Delivery of 5-Aminolevulinic Acid Esters to the Cervix

5-Aminolevulinic acid (5-ALA)-mediated photodynamic therapy has been proposed as an alternative, cervix-sparing treatment for cervical intraepithelial neoplasia (CIN). In this context, topical application of 5-ALA to the cervix is beneficial due to the small necessary dose and its minimal side effects. Therefore, lipophilic 5-ALA esters, such as hexylaminolevulinate (HAL), have led to improved local bioavailability and therapeutic efficacy. Hydrogels have shown to be more appropriate for the local delivery of these derivatives, but due to the limited long-term stability of such formulations at 25 degrees C, the development of an extemporaneously prepared hydrogel targeting CIN can be advantageous. Therefore, a poloxamer 407 thermosetting gel, which is liquid at room temperature and becomes a semi-solid when in contact with the female genital tract, has been evaluated in vitro and in vivo. Rheological evaluation has shown that a 17.0% poloxamer 407 hydrogel with a sol-gel transition at 24.8 +/- 0.6 degrees C was the best formulation for easy application and optimal residence time. Furthermore, similarly to other hydrogels previously tested, such a formulation shows a more complete HAL release in vitro than conventional cream vehicles, and tends to increase porphyrin accumulation in nude mice skin. Finally, in vitro release profiles were correlated to the in vivo results.

Pharmacokinetics and selectivity of porphyrin synthesis after topical application of hexaminolevulinate in patients with cervical intraepithelial neoplasia

OBJECTIVE

Photodynamic therapy has the potential of a minimal invasive outpatient procedure for CIN patients at reproductive ages. The purpose of this study was to examine the pharmacokinetics and selectivity of porphyrin synthesis after topical application of hexaminolevulinate (HAL) in patients with cervical intraepithelial neoplasia (CIN).

STUDY DESIGN

Twenty-four women with CIN 1-3 received 4 mmol/L or 10 mmol/L HAL dissolved in thermolabile pluronic F 127 gel topically 5-720 minutes before surgical conization. The microscopic fluorescence pattern was quantified by ex vivo fluorescence spectroscopy at a wavelength of 635 nm and semiquantitatively by digital image analysis from cryosections.

RESULTS

With 4 and 10 mmol/L HAL, porphyrin fluorescence intensity increased over time, reaching a peak after 180-540 minutes application intervals in CIN and normal epithelium. However, the peak was much more pronounced in CIN than in normal tissues. The fluorescence intensity with 10 mmol/L was significantly higher than that with 4 mmol/L in CIN tissues (P < .05). Maximum intensity could generally be detected in the lower layer of the epithelium.

CONCLUSION

HAL seems to be a promising molecule for fluorescence diagnosis. For further treatment studies, we recommend application of 10 mmol/L HAL 300-540 minutes before photodynamic therapy in CIN.

Derivatives of 5-Aminolevulinic Acid for Photodynamic Therapy

Photodynamic therapy (PDT) is a clinical treatment that combines the effects of visible light irradiation with subsequent biochemical events that arise from the presence of a photosensitising drug (possessing no dark toxicity) to cause destruction of selected cells. Today, the most common agent used in dermatological PDT is 5-aminolevulinic acid (ALA). As a result of its hydrophilic character, ALA penetrates skin lesions poorly when applied topically. Its systemic bioavailability is limited and it is known to cause significant side effects when given orally or intravenously. Numerous chemical derivatives of ALA have been synthesised with the aims of either improving topical penetration or enhancing systemic bioavailability, while reducing side effects. In vitro cell culture experiments with ALA derivatives have yielded promising results. However, if ALA derivatives are to demonstrate meaningful clinical benefits, a rational approach to topical formulation design is required, along with a systematic study aimed at uncovering the true potential of ALA derivatives in photodynamic therapy. With respect to systemic ALA delivery, more study is required in the developing area of ALA-containing dendrons and dendrimers.

Efficacy in treatment of cervical HRHPV infection by combination of beta interferon, and herbal therapy in woman with different cervical lesions

Cervical dysplasia, a premalignant lesion that can progress to cervical cancer, is caused primarily by a sexually transmitted infection with an oncogenic strain of the human papillomavirus (HPV). The HPV infections are treated through destroying the clinical lesions: laser, cryotherapy, podophyllin... The hope is that by causing local tissue inflammation that the body will be stimulated to mount an antibody response and thereby prevent recurrence. In contrast to other prevention approaches, vaccines can reduce susceptibility in uninfected partners by stimulating the immune system. Aloe vera has also been reported to retard tumour growth and stimulate the immune response to viruses. A list of possible actions of propolis includes: antibacterial, antifungal, antiviral, antioxidant, anticarcinogenic, antithrombotic and immunomodulatory. Research on the possible role of some B vitamins in preventing cancer began in the last few decades, but however this complex have an influence on immune status. The aim of our study is to try to treat the HPV infection as confirmed cause of neoplastic transformation with some herbal therapy and interferon and to try define the guidelines in the management of the HPV positive patients. Goal of this paper is to search for evidence of efficacy of any treatment for HPV infection of the cervix mostly in woman with no concomitant CIN. Fifty five woman affected by HPV genital infection were enrolled in the study from September 2005 to April 2006. Patients were classified according to the results of the HPV testing prior and after the therapy. Patients were randomized into two groups: the first group was HPV positive woman treated with other than recommended therapy (n=20), (control group); the second group was pharmacologically treated with intravaginal administration of an interferon and aloe vera-propolis in recommended scheme (n=35) with treatment of the possible fungal or bacterial genital infection prior to the specific therapy. The almost same therapy was recommended to the male partner. Patients from the second group used B complex during the therapy. Patients were retested for the HPV presence after three or six month from therapy depend of the presence bacterial or fungal genital coinfection. Three months after applied therapy HPV infection was still present in more than 90% of the patients in the first group. In the second group treated according to the recommended therapy scheme HPV infection disappeared in 71.42% of the patients after three months and in 100% of patients after six months. Samples of the cervical smear for the HPV analysis were being taken during routine gynecological examinations, by using sticks with cotton, taken from the Digene Specimen Collection Kit, from the whole surface of a portion, and by mild rotating moves from the outer cervical entrance. Our results suggest that the combination of interferon and herbal therapy with B complex is effective, atraumatic and simple non-surgical treatment of HPV infection. Since prospective efficacy trials will take several years to complete, considering alternative approaches is also worthwhile.

The future of photodynamic therapy in oncology

The medicinal properties of light-based therapies have been appreciated for millennia. Yet, only in this century have we witnessed the birth of photodynamic therapy (PDT), which over the last few decades has emerged to prominence based on its promising results and clinical simplicity. The fundamental and distinguishing characteristics of PDT are based on the interaction of a photosensitizing agent, which, when activated by light, transfers its energy into an oxygen-dependent reaction. Clinically, this photodynamic reaction is cytotoxic and vasculotoxic. While the current age of PDT is based on oncological therapy, the future of PDT will probably show a significant expansion to non-oncological indications. This harks back to much of the original work from a century ago. Therefore, this paper will attempt to predict the future of PDT, based in part on a review of its origin.

Photodynamic Therapy for Cervical Intraepithelial Neoplasia

OBJECTIVES

Photodynamic therapy (PDT) is a minimally invasive treatment for cervical intraepithelial neoplasia (CIN). We report the effectiveness of PDT in 105 cases of CIN.

METHODS

All patients received photofrin (PHE) 2 mg/kg intravenously and, 48-60 h later, phototherapy was performed using the Excimer dye laser or a YAG-OPO laser with an irradiation dose of 100 J/cm(2) using 630 nm wavelength.

RESULTS

Mild photosensitivity occurred in 48% (50/105) of patients. The complete response (CR) rate was 90% (94/105) at 3 months following treatment. In the remaining 11 patients, 5 patients had CIN1, 2 patients had CIN2, and 4 patients had mild cytologic findings. However, in 9 of these 11 patients, CR was achieved 6 months after PDT. In 69 patients, human papilloma virus (HPV) typing was performed before and after PDT therapy. Pre-treatment, 64 of 69 patients (93%), were HPV-positive including 30 cases of high-risk HPV (43%). Testing performed 3, 6 and 12 months following PDT revealed no HPV-DNA in 75% (52/69), 74% (48/65) and 72% (41/57) of patients. At present, the median follow-up period is 636 days (90-2,232 days). In 3 patients, recurrence requiring surgical treatment was identified at 646, 717 and 895 days after PDT.

CONCLUSIONS

PDT is an effective and minimally invasive treatment for CIN, which also appears to eradicate HPV infection.

Time-dependent hexaminolaevulinate induced protoporphyrin IX distribution after topical application in patients with cervical intraepithelial neoplasia: A fluorescence microscopy study

BACKGROUND AND OBJECTIVES

Compared to the conventional management of cervical intraepithelial neoplasia (CIN) the potential advantage of photodynamic therapy (PDT) for the treatment of cervical human papilloma virus (HPV)-related disease encompasses a minimal invasive procedure with reduced risk of profuse bleeding as a consequence of conization, and possibly more favorable long-term results avoiding cervical stenosis. At present little is known about the precise time-dependent distribution and histological localization of hexaminolaevulinate (HAL) induced protoporphyrin IX (PPIX) fluorescence in healthy tissue and in CIN. The aim of this study was to use ex vivo fluorescence microscopy to determine whether PPIX is selectively induced by neoplastic cells of the cervical epithelium at various times after topical application.

STUDY DESIGN/MATERIALS AND METHODS

Cold cream containing 0.5% HAL was applied by means of cervical cap over various periods of time. We analyzed 52 healthy cervical mucosa and 84 CINs.

RESULTS

At time delay 100 (+/-10) minutes, high epithelial fluorescence and a significant selectivity between epithelium and underlying lamina propria was found. By contrast, no significant difference between healthy and neoplastic tissues, or between low and high-grade epithelial dysplasia (P > or = 0.05), was observed at any time point.

CONCLUSIONS

Application of HAL 0.5% cream to the cervix induced selective fluorescence in epithelial cells. The optimal ratio with a homogeneous PPIX distribution was obtained after 100 ( +/- 10) minutes cream application, which should be evaluated further for PDT.

EUS-guided photodynamic therapy of the pancreas: a pilot study

BACKGROUND

Photodynamic therapy of pancreatic cancer by using percutaneously placed light catheters has been reported. The feasibility and safety of EUS-guided photodynamic therapy of the pancreas was studied in a porcine model.

METHODS

After injection of porfimer sodium, a 19-gauge needle was inserted into the pancreas, the liver, the spleen, and the kidney under EUS guidance. A small diameter quartz optical fiber was passed through the EUS needle and used to illuminate the tissue with laser light. The tissue response to photodynamic therapy was examined.

RESULTS

Localized tissue necrosis was achieved in all organs, without significant complication. There was no significant difference in inflammation induced by photodynamic therapy within the various organs.

CONCLUSIONS

EUS-guided photodynamic therapy is a safe and simple technique that can induce small areas of focal tissue ablation within the liver, the pancreas, the kidney, and the spleen, and potentially could be used to treat a variety of benign and malignant conditions.

Fluoreszenzdiagnostik mit 5-ALA-Thermogel bei zervikaler intraepithelialer Neoplasie

OBJECTIVE

To study the pharmacokinetics and selectivity of 5-aminolevulinic acid (5-ALA) from 5-ALA thermolabile gel formulation in cervical intraepithelial neoplasia (CIN). The novel thermogel Pluronic F127 is liquid at cold temperatures and turns into a gel-like consistency at body temperature, thereby improving adhesion of 5-ALA to the cervix uteri.

METHODS

27 female patients with CIN 1-3 were included in this study. Thirty minutes to 12 h before conisation, 10 mL of thermo-gel containing either 4, 10, or 20% of 5-ALA were topically applied to the cervix. Biopsies were taken from the lesions as well as normal surrounding epithelial tissue for histological examination, fluorescence microscopy and spectrometry.

RESULTS

The thermogel Pluronic F127 was easy to handle and proved reliable as vehicle carrier. 5-ALA induced porphyrin fluorescence was maximal after application of 10% 5-ALA thermogel. We observed the higher porphyrin fluorescence intensity within the CIN lesions (1,116 +/- 241 AU), as compared to normal adjacent epithelium (704 +/- 166 AU). This difference was statistically significant (p < 0.05). Four to six hours after application, porphyrin fluorescence in dysplastic epithelium reached maximal intensity, and tumor selectivity was the highest in CIN 3 achieving a tumor-to-normal ratio of 3.5. Compared to other studies employing 5-ALA, the thermogel preparation of 5-ALA leads to twofold increase in the porphyrin selectivity.

CONCLUSIONS

The thermogel Pluronic F127 seems to improve the local cervical drug application. Based on these results, we recommend the application of a 10% 5-ALA thermogel formulation 4-6 h prior to photodynamic therapy in CIN.

In vivo fluorescence kinetics and photodynamic therapy in condylomata acuminata

BACKGROUND

Topical application of 5-aminolaevulinic acid (ALA) to condylomata acuminata leads to accumulation of protoporphyrin IX (PpIX); therefore ALA-induced photodynamic therapy (ALA-PDT) appears to be a potential treatment.

OBJECTIVES

To investigate in vivo the PpIX fluorescence time course after topical application of ALA in order to determine the optimal time for irradiation, and to assess the efficacy of subsequently performed ALA-PDT.

METHODS

Fluorescence kinetics was studied in 12 male patients with condylomata acuminata. Confirmation of diagnosis was established with conventional histology and polymerase chain reaction. Lesions were treated with 20% ALA and irradiated at the optimal time with a dose of 70 J cm-2 or 100 J cm-2 light. An additional session with 100 J cm-2 was administered 1 week later to lesions that persisted.

RESULTS

The in vivo study of fluorescence kinetics indicated that the optimal time for irradiation varied among patients from 6 to 11 h. The overall cure rate was 72.9%, 12 months after treatment.

CONCLUSIONS

Topical ALA-PDT is a potentially effective treatment for condylomata acuminata.

Chapter 17: Genital human papillomavirus infections--current and prospective therapies

Many therapies are available for the treatment of human papillomavirus (HPV)-associated disease, particularly external genital warts. However, at present, these therapies aim to remove the lesion rather than specifically target HPV infection. When disease and infection are local, as in cervical intraepithelial neoplasia (CIN), excisional therapies removing lesion and transformation-susceptible cells are highly effective. However, when infection is regional, as is usually the case for the anogenital warts, vulval intraepithelial neoplasia (VIN), anal intraepithelial neoplasia (AIN), penile intraepithelial neoplasia, and vaginal intraepithelial neoplasia, then current treatments are generally inadequate, with high recurrence rates. Future therapies will be directly or indirectly antiviral, targeting HPV protein functions or enhancing the ability of the immune system to resolve infection or inducing apoptosis indirectly in HPV-infected cells. In the short to the medium term, immunotherapies for low-grade disease are the most likely to be in the clinic. Vaccines targeting the E1 and E2 early proteins combined with immunomodulators or conventional adjuvants that induce a strong cell-mediated HPV antigen-specific response and good immune memory would be the predicted combination. Vaccines designed to target high-grade intraepithelial disease, even when used in combination with immunomodulators, are unlikely to effect lesion clearance in more than a fraction of the cases. However, they may have a role as adjunct therapy after cervical conization to prevent the recurrence of CIN or HPV reinfection. They certainly appear to have a role in multifocal disease, such as VIN and AIN, where partial clearance may be effected and lesion size reduced enough for effective ablative or excisional therapy. It seems unlikely that anti-HPV chemotherapies specifically targeting HPV protein functions will be in the clinic in the medium term. However, agents such as indole-3-carbinol have shown efficacy in small clinical trials, and if these effects are confirmed in larger, randomized, placebo-controlled trials, they could be clinically useful.

A randomised, double-blind, placebo-controlled trial of photodynamic therapy using 5-aminolaevulinic acid for the treatment of cervical intraepithelial neoplasia

Photodynamic therapy (PDT) using topical 5-aminolaevulinic acid (ALA) has been used to treat histologically confirmed cervical intraepithelial neoplasia (CIN-I and -I/II) in a randomised, double-blind, placebo-controlled protocol. Fluorescence microscopy revealed that topical application of 3% ALA in Intrasite Gel to the cervix for 3 hr resulted in the accumulation of protoporphyrin IX in the cervical epithelium. Treatment of CIN with ALA-PDT was well tolerated, with only 3/12 patients in the PDT arm (0/13 in the placebo arm) reporting any discomfort during illumination. Histologic examination of the treated tissue following loop excision 3 months post-PDT indicated that 33% of patients had no evidence of CIN, 42% had no change in the grade of their disease, whilst 25% exhibited an apparent progression of disease. In the control group, the respective figures were 31%, 38% and 31%. There was no significant difference in response between the groups receiving ALA-PDT and those receiving placebo treatment.

Photodynamic therapy of high-grade cervical intraepithelial neoplasia with 5-aminolevulinic acid

BACKGROUND AND OBJECTIVES

To determine the safety and efficacy of 5-aminolevulinic acid (ALA) as a topically applied photosensitizer for photodynamic therapy (PDT) of cervical intraepithelial neoplasia (CIN).

STUDY DESIGNS/MATERIALS AND METHODS

Forty women, who were at least 18 years old with persistent biopsy-proven CIN 2 and CIN 3 within the previous 3 months of enrollment, underwent PDT in a phase I and II design. Five escalating radiant energies (increments of 25 J/cm(2), beginning at 50-150 J/cm(2)) using a Coherent Dye Model 920 argon pumped dye laser providing light at 630 nm (maximum output 0.8 W) were used to perform PDT with a fixed dose of ALA (200 mg/ml). ALA was placed in a cervical cap fitted to the cervix. After 90 minutes, the cap was removed and the ectocervix was illuminated for 5-16 minutes, depending on the irradiance. Success was defined as the absence of CIN on Pap smear or colposcopic examination at 12-months. Patients were monitored for toxicity.

RESULTS

Thirty-two women (80%) completed the study with 1 year of follow-up. Sixty percent had CIN 3 and 40% CIN 2. Success rates at 4, 8, and 12 months were 51, 46, and 31%, respectively, and were not light-dose dependent. Three patients progressed from CIN 2 to CIN 3. Toxicity was tolerable and only consisted of spotting, vaginal discharge, mild cramping, and vaginal warmth. There was no apparent dose relationship to toxicity.

CONCLUSIONS

PDT at this light and ALA dose is well tolerated but has minimal activity in the treatment of CIN 2 and CIN 3. Other doses and schedules of light and ALA or novel photosensitizers may improve efficacy.

Detection of female lower genital tract dysplasia using orally administered 5-aminolevulinic acid induced protoporphyrin IX: a preliminary study

OBJECTIVE

Previous studies have suggested that 5-aminolevulinic acid (ALA) may be used topically on the cervix to allow optical detection of cervical dysplasia, based on the fluorescence of protoporphyrin IX (PpIX) synthesized in situ from ALA. However, the uniformity of distribution of topically applied PpIX and the sensitivity and specificity of detection are not optimal. The current study was undertaken to demonstrate the feasibility of administering ALA by mouth (po) with the hypothesis that systemic administration might provide a more reliable diagnostic tool.

METHODS

Oral ALA was administered to 14 patients with abnormal Pap smears in a dose- and time-intensity design. Institutional review board approval was obtained. A starting dose of 10 mg/kg of po ALA was administered and colposcopy was performed in 3 patients at 1 h, 3 patients at 2 h, 6 patients at 3 h, and 2 patients at 4 h. The study was written with the intent to increase the dose in 10 mg/kg increments if fluorescence was not detected; however, fluorescence was detected at the first dose level. Liver function tests were checked pre and post ALA and follow-up telephone calls were made regarding possible side effects. Both white and blue light colposcopy examinations were performed by two blinded clinicians and biopsies of all abnormal areas were performed.

RESULTS

All patients tolerated po ALA well, with no systemic side effects. At the 10 mg/kg dose there was no reported nausea or photosensitivity. Optimal fluorescence was achieved at the 3-h time point, with quenching noted at the 4-h time point. Excellent absorption was documented with fluorescence of the lip demonstrated with Wood's lamp. In some cases fluorescence correlated with dysplasia on biopsy.

CONCLUSION

5-ALA given via the po route and at the dose and time period studied is well tolerated and affords fluorescence of the cervix. Future study is needed to demonstrate the successful identification of dysplastic lesions, with the ultimate goal of treating dysplasia of the lower genital tract with 5-ALA and light therapy.

Photodynamic effects induced by aminolevulinic acid esters on human cervical carcinoma cells in culture

Fluorescence diagnosis and photodynamic therapy using 5-aminolevulinic acid (ALA) provide new methods for the detection and treatment of cervical cancer and especially its precursors. However, these techniques are restricted by the rate of uptake of the hydrophilic ALA, its poor diffusion through the bilayer of biological membranes or both. In this study we evaluated the effect of some esterified ALA derivatives on the induction of the endogenous photosensitizer, protoporphyrin IX (PpIX), and the photodamage in cultured human cervical cells (C33-A and CaSki). The kinetics of PpIX accumulation showed that ALA esters, especially the ALA-hexylester (h-ALA), induced significantly faster PpIX formation than ALA at the same concentration (0.5 mM). The PpIX induction showed a dose-dependent characteristic. The highest PpIX values could be achieved by an up to 1.3-13-fold lower concentration of ALA esters than with ALA. Using the Annexin V assay, apoptosis was found to be induced rapidly after irradiation in both ALA- and ALA esters-treated cells. On measuring mitochondrial activity, the incubation with h-ALA induced a more pronounced photodamage. The results indicate that improved or at least comparable photodynamic effects can be achieved by using remarkably lower doses of ALA esters.

Fluorescence detection of cervical intraepithelial neoplasia for photodynamic therapy with the topical agents 5-aminolevulinic acid and benzoporphyrin-derivative monoacid ring

OBJECTIVE

The aim of this study was to determine whether 2 photosensitizers, benzoporphyrin-derivative monoacid ring and 5-aminolevulinic acid, are selectively absorbed by dysplastic cervical cells after topical administration.

STUDY DESIGN

This phase I clinical trial involved 18 women with biopsy-proven cervical intraepithelial neoplasia at the Beckman Laser Institute, Irvine, Calif. Colposcopically directed cervical biopsy specimens obtained after 1.5, 3, or 6 hours of exposure to a randomly assigned photosensitizer were evaluated for selective drug absorption with hematoxylin and eosin staining and fluorescence microscopy.

RESULTS

After exposure to 5-aminolevulinic acid, cervical tissue showed maximal fluorescence in dysplastic cells relative to normal cells, with negligible stromal fluorescence. According to our detection methods benzoporphyrin-derivative monoacid ring demonstrated nonselective, diffusion-driven uptake, with fluorescence appearing in the superficial cells, followed by nonselective drug absorption in the remaining cells and stroma of the epithelium.

CONCLUSION

Our data demonstrated selective absorption of 5-aminolevulinic acid by dysplastic cervical cells. This agent therefore represents a promising photosensitizing prodrug for the treatment of cervical intraepithelial neoplasia with photodynamic therapy.

Recent advances in diagnosis and therapy of human papillomaviruses

Infection with human papillomavirus is extremely common throughout the world. Almost 50% of sexually active young women are infected with human papillomavirus and although most infections are transient, a subset has the potential to progress to invasive cancer. During the last 20 years, our understanding of the human papillomavirus life cycle and the role of human papillomavirus in human cancer has dramatically increased. Recent technological advances in human papillomavirus detection have provided the means to detect the presence of human papillomavirus with great sensitivity. In the context of patient care, there is still substantial debate regarding the optimal diagnostic and prognostic use of information derived from hybrid capture or polymerase chain reaction-based detection. The inventory of available treatment options is growing somewhat slowly. The most promising advances are being made in the clinical evaluation of candidates for prophylactic vaccination. This review is focused on the current status and future directions of prevention, diagnosis and therapy.