Pharmacokinetics and selectivity of aminolevulinic acid-induced porphyrin synthesis in patients with cervical intra-epithelial neoplasia

Comparative study of photodynamic therapy (PDT) of cervical low-grade squamous intraepithelial lesion (LSIL)

BACKGROUND

Prevention of high-risk HPV (HR-HPV) infection and effective medical intervention of persistent HPV infection and precancerous lesions are critical for the prevention of cervical cancer.

AIMS

The aim of this retrospective comparative study was to evaluate the outcomes of ALA PDT and observation only in the management of low-grade squamous intraepithelial lesions (LSIL).

METHODS

In PDT Group (n = 138), ALA PDT was applied to patients with colposcopic biopsy confirmed cervical LSIL accompanied with HR-HPV infection longer than 1 year or HPV 16/18 subtype infection. Cervical LSIL only patients received 3 times of ALA PDT and those with concurrent cervical canal or vaginal lesions received 6 times ALA PDT. Control Group (n = 69) received observation only. Colposcopy, TCT and HPV typing were performed before and after treatment. Patients were followed up for up to two years.

RESULT

The observation group showed 26.1%, 34.8% and 53.6% HR-HPV negative conversion at 3-6, 12 and 24 months, respectively. LSIL regression rate of the observation group was 33.33%, 36.23% and 65.22% at 3-6, 12 and 24 months, respectively. There was 62.32%, 80.56% and 89.22% patients achieved HPV clearance at 3-6, 12 and 24 months after PDT treatment, respectively. The LSIL remission rate was 89.86%, 94.40% and 96.08% at 3-6, 12 and 24 months after ALA PDT, respectively. The abnormal TCT (≧ ASCUS) was reduced from 92% to 10.1%, 4.6% and 3.9% at 3-6, 12 and 24 months after ALA PDT, respectively. The patient age was not a factor affecting the clearance of HPV infection and the LSIL regression rate of PDT treatment.

CONCLUSIONS

This study demonstrates that the application of multiple ALA PDT treatments has added value in achieving both short-term and long-term HPV and lesion clearance.

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.

A comparative study of treatment of cervical low-grade squamous intraepithelial lesions (LSIL)

BACKGROUND AND AIMS

Low-grade squamous intraepithelial lesion (LSIL) is one of two categories of cervical intraepithelial lesions. Given that controversy exists regarding its management, this comparative study aimed to evaluate the effect of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in treating LSIL of the high-risk human papillomavirus (HR-HPV)-infected cervix.

METHODS

A total of 218 patients (25-45 years old) with cervical LSIL associated with HR-HPV who underwent ALA-PDT, loop electrosurgical excision procedure (LEEP), or observation only were included. The clearance rates of cervical LSIL and HR-HPV between the ALA-PDT, LEEP, and observation groups were compared at 6 and 12 months follow-up. Adverse reactions were also compared. The factors affecting the clearance on ALA-PDT of cervical LSIL were evaluated.

RESULTS

There were no statistically significant differences in lesion and HR-HPV clearance rates between the ALA-PDT and LEEP groups at 6 and 12 months. However, the lesion and HR-HPV clearance rates were significantly higher in the ALA-PDT group than that in the observation group. The adverse reaction rate was significantly lower in the ALA-PDT group than in the LEEP group.

CONCLUSION

For patients with cervical LSIL, the lesion and HR-HPV clearance rates after ALA-PDT were close to those after LEEP and significantly higher than in the observation group. Moreover, the adverse reaction rate for ALA-PDT was much lower than that for LEEP. Therefore, ALA-PDT provides a new option for the minimally invasive treatment of cervical LSIL.

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.

Mechanistic study of PpIX accumulation using the JFCR39 cell panel revealed a role for dynamin 2-mediated exocytosis

5-aminolevulinic acid (5-ALA) has recently been employed for photodynamic diagnosis (ALA-PDD) and photodynamic therapy (ALA-PDT) of various types of cancer because hyperproliferating tumor cells do not utilize oxidative phosphorylation and do not efficiently produce heme; instead, they accumulate protoporphyrin IX (PpIX), which is a precursor of heme that is activated by violet light irradiation that results in the production of red fluorescence and singlet oxygen. The efficiencies of ALA-PDD and ALA-PDT depend on the efficient cellular uptake of 5-ALA and the inefficient excretion of PpIX. We employed the JFCR39 cell panel to determine whether tumor cells originating from different tissues can produce and accumulate PpIX. We also investigated cellular factors/molecules involved in PpIX excretion by tumor cells with the JFCR39 cell panel. Unexpectedly, the expression levels of ABCG2, which has been considered to play a major role in PpIX extracellular transport, did not show a strong correlation with PpIX excretion levels in the JFCR39 cell panel, although an ABCG2 inhibitor significantly increased intracellular PpIX accumulation in several tumor cell lines. In contrast, the expression levels of dynamin 2, which is a cell membrane-associated molecule involved in exocytosis, were correlated with the PpIX excretion levels. Moreover, inhibitors of dynamin significantly suppressed PpIX excretion and increased the intracellular levels of PpIX. This is the first report demonstrating the causal relationship between dynamin 2 expression and PpIX excretion in tumor cells.

Efficacy of commercially available biological agents for the topical treatment of cervical intraepithelial neoplasia: a systematic review

BACKGROUND

Cervical cancer is a major public health issue in the world, especially in developing countries. It can be prevented through vaccination against HPV (primary prevention) and through screening and treatment of cervical intraepithelial neoplasia (CIN) (secondary prevention). Surgical methods for treatment of CIN are linked to complications such as bleeding and adverse pregnancy outcomes. Furthermore, these methods are not generally available in resource-poor settings. Therefore, topical agents for local application on the cervix have been used since decades to overpass complications and limitations of the surgical methods.

AIMS

Review of the literature on the efficacy of commercially available biological agents used for topical treatment of cervical intraepithelial neoplasia (CIN).

METHODS

A systematic search through PubMed and the Cochrane database was performed up to December 2017, using the medical subheadings (MesH) for topical agent, treatment, and cervical intraepithelial neoplasia. Appropriate inclusion/exclusion criteria have been used for the selection of eligible clinical studies. Clinical studies containing a minimum of 20 women, aged 18-50 with a diagnosis of CIN 1-3, and at least a 4 weeks follow-up after the end of the topical treatment were included.

RESULTS

The initial electronic database search resulted in a total of 849 articles. After screening titles and abstracts, 62 articles were selected as potential studies. Of these, six articles were included in the review after reading the full text: two were on 5-FluoroUracil, two on trans retinoic acid, one on Imiquimod, and one on Cidofovir. The reported regression/remission rates for CIN differed among studies. In CIN2 patients, the overall remission rate ranged between 43 and 93% for the active agents.

CONCLUSION

Among the topical agents studied, 5-FluoroUracil showed good remission rates above 80%. Varying results seen in this review is due to the differences in quality of the design between studies. Large-scale and less biaised studies are needed to elucidate the true efficacy and safety of topical agents in the treatment of CIN.

Ex vivo evaluation of the effect of photodynamic therapy on skin scars and striae distensae

BACKGROUND

Skin scars and striae distensae (SD) are common dermal disorders with ill-defined treatment options. There is emerging clinical evidence for use of photodynamic therapy (PDT) in treating skin fibrosis. Therefore, the aim here was to investigate the effect of PDT on skin scars and SD in an ex vivo model of human skin scarring.

METHODS

Photodynamic therapy, with 5ALA or MALA in addition to illumination with 40 J/cm(2) of red light, was applied to striae alba, fine line, hypertrophic and keloid scars ex vivo (n = 18). General morphology was assessed by H&E, Herovici's and Weigert's differential staining. Apoptosis, proliferation, metalloproteinase 3 and tropoelastin expression were quantified immunohistochemically, and differential gene expression of proliferating cell nuclear antigen (PCNA), collagen (COL) type I and type III, matrix metalloproteinase 3 (MMP3) and tropoelastin (ELN) was assessed by real-time quantitative reverse transcription polymerase chain reaction.

RESULTS

Apoptosis increased, which correlated with decreased proliferation and PCNA gene expression. Post-PDT, matrix components were found to be re-organised in both hypertrophic and keloid scars. COLI and COLIII gene expression levels decreased, whilst MMP3 and ELN increased significantly post-PDT compared to normal skin and untreated controls (P < 0.05). However, no significant difference between 5ALA and MALA-PDT treatments was observed.

CONCLUSION

Using our unique ex vivo model, we show for the first time morphological and cellular effect of application of PDT, which correlates with the degree and severity of dermal fibrosis. In view of this, PDT may be ideal in targeting treatment of abnormal skin scarring.

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.

Treatment of HPV infection-associated cervical condylomata acuminata with 5-aminolevulinic acid-mediated photodynamic therapy

The aim of this study was to investigate the efficacy of 5-aminolaevulinic acid (ALA)-mediated photodynamic therapy (PDT) in treatment of human papillomavirus (HPV)-associated cervical condylomata. A total of 56 patients with cervical and external condylomata lesions were recruited for this open-label study. HPV genotyping of exfoliated cells collected from the cervix and external lesions was performed. Cervical lesions were treated with PDT by applying ALA gel (10%) to the surface of the cervix for 4 h followed by irradiating with a 635 nm laser at 100 J cm(-2). PDT was repeated at 2-week intervals if lesion and HPV infection remained. Patients were followed up for 6-24 months. Genotyping analysis revealed four HPV subtypes (HPV6, 11, 16 and 18). The overall complete remission rate of 1-4 sessions of treatments was 98.2% and the corresponding HPV clearance rate was 83.9%. Ten cases showed complete removal of cervical lesions and HPV infection after a single treatment. Recurrence rate was 3.6%. Adverse effects were minimal and no structural complications were reported. In conclusion, topical ALA PDT is safe and effective for eradicating cervical HPV infection and eliminating condylomata lesion. Its definitive role in treating cervical condylomata deserves further investigation.

Successful photodynamic therapy with topical 5-aminolevulinic acid for five cases of cervical intraepithelial neoplasia

OBJECTIVES

Photodynamic therapy (PDT) is a minimally invasive treatment for cervical intraepithelial neoplasia. The purpose of this study was to assess the feasibility and effectiveness of PDT in patients with CIN and high-risk HPV infection.

METHODS

Five patients diagnosed CIN 2 or CIN 3 with human papillomavirus (HPV) infection were included. Each patient had gynecologic examination including cervical cytology, HPV DNA testing, colposcopy and biopsy. Two grams of 5-aminolevulinic acid (ALA) gel (118 mg/g) was topically applied to the cervix and covered with a special plastic cap for 3-4 h, followed by 20 min illumination of both ecto- and endo-cervical canal with red coherent light (wavelength 633 nm) using a PDT laser and a special light catheter. The PDT therapy was repeated with an interval of 1 week. Follow-up examination including biopsy and histology, colposcopy, HPV DNA testing were carried out after 3, 6 and 9 months.

RESULTS

Treatment could be accomplished in all cases and no severe side effect was encountered. All the CIN2 patients had a complete response for 9 months and one CIN3 HPV remained positive for 6 months after three or four treatments.

CONCLUSION

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

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.

Medical management of vulvar intraepithelial neoplasia

OBJECTIVE

To determine which nonsurgical treatments have been assessed for the treatment of vulvar intraepithelial neoplasia (VIN) and what the outcomes of such treatment might be.

MATERIALS AND METHODS

The English literature over the last 25 years was searched on Medline.

RESULTS

A wide variety of nonsurgical treatments was identified and the outcomes were very similar. These treatments showed responses rates varying between 10% and 60%. Responses were poorly defined, however, and few if any studies had large enough subject numbers or long enough follow-up to allow robust conclusions.

CONCLUSIONS

Although VIN is a condition in which there would seem to be a pressing need for nonsurgical interventions, none of the nonsurgical treatments reviewed resulted in optimal outcomes. No one treatment seemed to be superior. There is a need for consensus on how outcomes are measured and a move toward large well-constructed studies is recommended. Because VIN is uncommon, there is a strong case for establishing research collaboratives.

Fluorophor-labeled spermidine derivatives as fluorescent markers in optical tumor imaging

Up-regulation of polyamine transporters on the surface of tumor cells and the internalization of biogenic polyamines by active transport processes may be exploited for the accumulation of spermidine derivatives as reporter molecules. We have synthesized and tested fluorophor-labeled spermidine derivatives for the development of a new class of intraoperative tumor imaging agents. In vitro uptake experiments and initial in vivo imaging studies illustrated that fluorophor tagged spermidine derivatives show tumor accumulation.

Photodynamic effects of Radachlorin on cervical cancer cells

PURPOSE

Photodynamic therapy (PDT) is a novel treatment modality, which produces local tissue necrosis with laser light following the prior administration of a photosensitizing agent. Radachlorin has recently been shown to be a promising PDT sensitizer. In order to elucidate the antitumor effects of PDT using Radachlorin on cervical cancer, growth inhibition studies on a HPV-associated tumor cell line, TC-1 cells in vitro and animals with an established TC-1 tumor in vivo were determined.

MATERIALS AND METHODS

TC-1 tumor cells were exposed to various concentrations of Radachlorin and PDT, with irradiation of 12.5 or 25 J/cm(2) at an irradiance of 20 mW/cm(2) using a Won-PDT D662 laser at 662 nm in vitro. C57BL/6 mice with TC-1 tumor were injected with Radachlorin via different routes and treated with PDT in vivo. A growth suppression study was then used to evaluate the effects at various time points after PDT.

RESULTS

The results showed that irradiation of TC-1 tumor cells in the presence of Radachlorin induced significant cell growth inhibition. Animals with established TC-1 tumors exhibited significantly smaller tumor sizes over time when treated with Radachlorin and irradiation.

CONCLUSION

PDT after the application of Radachlorin appears to be effective against TC-1 tumors both in vitro and in vivo.

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.

Cellular damage to human hepatocytes through repeated application of 5-aminolevulinic acid

BACKGROUND/AIMS

5-Aminolevulinic acid (ALA), a precursor of porphyrins is used for photodynamic diagnosis and therapy within topical or systemic applications. A potential toxic effect on the human liver is of major interest and therefore we investigated the impact of a repeated application of ALA without illumination on cultures of human hepatocytes.

METHODS

After ALA treatment of hepatocytes in vitro the porphyrin synthesis, albumin secretion, liver-specific enzyme release, and malondialdehyde levels were determined. In order to reduce levels of reactive oxygen substances, mannitol and the antioxidant enzymes superoxide dismutase and catalase were supplemented.

RESULTS

Porphyrin biosynthesis by human hepatocytes in vitro was repeatedly stimulated by ALA (0.001-1.0 mM), which was indicated by an accumulation of protoporphyrin IX. A repetitive treatment (up to four times) of hepatocytes with ALA resulted in an impairment of the hepatic function and viability, depending on the ALA concentration (0.1-1.0 mM) and frequency of application (2-3 times). This was also accompanied by increased malondialdehyde levels indicating enhanced lipid peroxidation. Only superoxide dismutase was able to reduce cellular damage and prevent specific function.

CONCLUSIONS

Repeated, not single, ALA treatment without illumination may cause deleterious effects to the liver, which are mediated by oxygen radicals and inhibited by an antioxidant.

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.

Management of precursor lesions of cervical carcinoma: history, host defense, and a survey of modalities

Before the initiation of screening and treatment for cervical cancer precursors, approximately 3% to 4% of women were destined to eventually develop cervical cancer. During the last 50 years the rate of cervical cancer incidence and mortality has decreased by more than 75% primarily because of the widespread availability of cervical cytologic screening and of treatment for documented cervical precancer. Successful screening of the entire population and appropriate treatment of lesions could theoretically reduce this risk to one tenth of the risk of an unscreened population [7,28]. The relatively recent understanding of the etiology of cervical cancer precursor lesions and of the immune response to them has given new direction to management options that incorporate healthy habits and dietary measures as part of traditional ablative or excisional treatment options. As we look to the future we can expect that new markers that more specifically identify individuals at-risk for cervical precancer and cancer will be developed and take precedence in cervical screening. At the same time, treating the cause of these lesions, rather than the result, should provide less traumatic and more successful therapies. To this end, harnessing the immune system through immune response modifiers and HPV vaccines seems to be on the horizon, as do new chemopreventative approaches. Of all human cancers, only cervical cancer, once the second most common cancer among women, stands on the threshold of being virtually eliminated.

Synthesis and characterization of water-insoluble and water-soluble dibutyltin(IV) porphinate complexes based on the tris(pyridinyl)porphyrin moiety, their anti-tumor activity in vitro and interaction with DNA

The water-insoluble and water-soluble organotin(IV)porphinate complexes based on the tris-(4-pyridinyl)porphyrin and tris(N-methyl-4-pyridiniumyl)porphyrin moieties were synthesized and characterized by elemental analysis, (1)H NMR, IR and electrospray ionization mass spectra. The in vitro activity of the compounds against P388 leukemia and A-549 was determined. The results show that the anti-tumor activities of organotin(IV)porphinate is related to the water solubility of the compounds and the central ion in the porphyrin ring. The interaction between the water-soluble dibutyltin(IV) porphinate (7 and 10) complexes and DNA has been investigated. The result shows that compounds 7 and 10 cause DNA hypochromism measured by A(260), a slight increase in the viscosity of the DNA, and an increase in the melting point of DNA by 2.9 and 1.6 degrees C, respectively at DNA(base)/Drug(Por) ratios of 60. The binding constants to DNA were 1.35+/-0.16 x 10(7) M(-1) (7) and 1.45+/-0.12 x 10(6) M(-1) (10) determined using EB competition method based on the porphyrin concentration, which is 20 and five times greater than that of precursor porphyrins [5-p,o-(carboxy)methoxyphenyl-10,15,20-tris(N-methyl-4-pyridiniumyl)] porphyrin (p,o-tMPyPac) to DNA. Electrophoresis test shows that the compounds cannot cleave the DNA. According to the electrophoresis test result and all the above results, the cytotoxic activity against P388 and A-549 tumor cells appears not to come from the cleavage of DNA caused by the compounds but from the high affinity of compounds to DNA.

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.

Localization and staging of cervical intraepithelial neoplasia using double ratio fluorescence imaging

A phase zero evaluation of a new fluorescence imaging technique for diagnosing cervical intraepithelial neoplasia (CIN) was performed. The fluorescence imaging prototype performed quantitative imaging of Protoporphyrin induced by a topically applied aminolevulinic acid using double ratio (DR) fluorescence imaging technique developed by our group. A total of 38 patients were in the protocol, with 16 colposcopically selected for biopsy. Fluorescence images of these 16 patients were taken, 19 sites were biopsied, and the disease was staged histopathologically. DR fluorescence imaging of the cervix using our general purpose prototype appeared to be cumbersome but feasible. In four cases strongly localized fluorescent hotspots were observed at the location where the disease was colposcopically visible. In the other cases the fluorescence showed a more diffuse multifocal image. The value of the DR determined at the site of biopsy correlated in a statistically significant way with the histopathologically determined stage of the disease [Spearman rank correlation, r=0.881, p<0.001 (confidence interval 0.7044-0.9552)]. This suggests that noninvasive staging of CIN using this technique is feasible. We believe that the results of this study justify the development of a dedicated device that combines regular white light colposcopy with DR fluorescence imaging.

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.

Fluorescence staining of oral cancer using a topical application of 5-aminolevulinic acid: fluorescence microscopic studies

INTRODUCTION

Topical application of 5-aminolevulinic acid (5-ALA) by means of a rinsing solution has been shown to be a promising new procedure in the diagnosis of oral malignancies. However, for assessing the reliability of this method regarding fluorescence-guided tumor resections and photodynamic therapy, further information on the distribution and penetration depth of 5-ALA-induced protoporphyrin IX (PPIX) in the tissue is needed.

METHODS

24 patients suffering from oral cancer were included in this investigation. Biopsies were taken immediately after fluorescence examination and either used as native sections for immediate fluorescence microscopic examination (n = 3) or shock frozen in liquid nitrogen and prepared as frozen sections (n = 46). Fluorescence imaging and digital image processing were utilized in order to determine the presence of PPIX in regions of various histologies as well as the penetration depth of PPIX into solid tumor.

RESULTS

PPIX fluorescence in the tissue was limited to the epithelium. Both normal and dysplastic epithelium showed PPIX fluorescence. In the stroma, no PPIX fluorescence was found. In some cases (n = 3/4) invasive carcinomas did not show PPIX fluorescence, while the adjacent or overlying normal epithelium was strongly fluorescent. The penetration depth of PPIX after topical application of 5-ALA was found to be limited to less than 1 mm.

CONCLUSION

PPIX fluorescence induced by topical application of 5-ALA can be very useful in the determination of superficial tumor margins. However, due to the limited penetration depth there is a risk of not accurately recognizing the infiltration depth of solid tumors. The aim of further investigations will be to assess the tissue distribution and depth of penetration of PPIX following systemic application of 5-ALA.

Melatonin reduces the oxidation of nuclear DNA and membrane lipids induced by the carcinogen delta-aminolevulinic acid

Well known are the anti-oxidant, free radical-scavenging and anti-tumorigenic properties of melatonin. delta-Aminolevulinic acid (ALA) is a precursor of heme synthesis. When over-produced and accumulated in tissues, ALA is a potential carcinogen, such as in the course of acute intermittent porphyria, hereditary tyrosinemia and lead poisoning. Our aim was to examine the potential protective effect of melatonin against oxidative damage to nuclear DNA and membrane lipids in rat lung and spleen caused by ALA. Changes in 8-hydroxy-2;-deoxyguanosine (8-OHdG) levels, an index of DNA damage, and the level of malondialdehyde + 4-hydroxyalkenals, an index of lipid peroxidation, were measured. Rats were injected with ALA (i.p., 40 mg/kg body weight, every other day) and/or with melatonin (i.p., 10 mg/kg body weight, 3 times daily) for 2 weeks. Both 8-OHdG and lipid peroxidation levels increased significantly in lung and spleen due to ALA treatment. Co-treatment with melatonin completely counteracted the effects of ALA. In conclusion, melatonin effectively protects nuclear DNA and lipids in rat lung and spleen against oxidative damage caused by the carcinogen ALA, and the indole may be of value as a supplement in patients suffering from molecular damage related to ALA accumulation.

Photodetection with 5-Aminolevulinic acid-induced protoporphyrin IX in the rat abdominal cavity: drug-dose-dependent fluorescence kinetics

In 75% of cases, ovarian carcinoma has already metastasized in the abdominal cavity at the time of diagnosis. For determination of the necessity for a supplementary therapy, in addition to surgical resection, it is important to localize and stage microscopical intraperitoneal metastases of the tumor. Intraperitoneal photodetection of tumor metastases is based on preferential tumor distribution of a fluorescent tumor marker. The time-dependent differences in drug concentration between tumor and normal (T/N) tissues can be used to visualize small tumors. We performed fluorescence measurements on abdominal organs and tumor in the peritoneal cavity of rats. 5-Aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) was used as the fluorescent marker. Three different drug doses (100, 25 and 5 mg/kg) were used and PpIX fluorescence profiles were followed up to 24 h after intravenous administration. Maximum T/N ratios were found 2-3 h after administration of ALA with all drug doses. A significant T/N tissue contrast was obtained for all abdominal organs tested after administration of 5 mg/kg.

Photodetection of cervical intraepithelial neoplasia using 5-aminolevulinic acid-induced porphyrin fluorescence

BACKGROUND

Screening for cervical carcinoma and its precursors is based on cervical cytology and diagnostic colposcopy. Despite the decrease in the incidence of cervical carcinoma in countries with a good screening program, this rate of decline is leveling off. Known problems are false-negative rates of cytology and low specificity of colposcopy. This clinical study examined the diagnostic potential of porphyrin fluorescence in patients with cervical intraepithelial neoplasia Grade 1-3 (CIN 1-3).

METHODS

Sixty-eight women attending our colposcopy clinic underwent a gynecologic examination, including cytology, human papillomavirus (HPV) testing, and colposcopy. They received 10 mL 0.5% or 1.0% 5-aminolevulinic acid (5-ALA) topically. After 30-360 minutes, real-time image analysis was performed, and spectra were obtained from 685 sites.

RESULTS

Due to rapid photobleaching, 0.5% 5-ALA proved ineffective for fluorescence assessment. Using 1% 5-ALA, the authors found that fluorescence intensities correlated with incubation time; however, fluorescence contrast showed a maximum at 60-90 minutes (ratio 11:1). HPV DNA positive lesions showed significantly higher fluorescence. Fluorescence imaging after 60-90 minutes achieved similar sensitivity and specificity compared with colposcopy in detecting CIN with 94% and 51% versus 95% and 50%, respectively. However, the specificity was markedly improved by fluorescence spectroscopy, achieving 75%. The evaluation of spectral measurements revealed significantly higher values for CIN compared with normal tissue and for CIN 2/3 compared with CIN 1 (P < 0.001).

CONCLUSIONS

Using a time interval of 60-90 minutes after topical application of 1% 5-ALA, the authors observed specific porphyrin fluorescence of CIN. Fluorescence spectroscopy promises to become a valuable tool for the diagnosis of CIN.

Photodynamic therapy of vulvar intraepithelial neoplasia using 5-aminolevulinic acid

Photodynamic (PDT) therapy is a relatively new technique with unique properties that make it attractive for the local treatment of superficial epithelial disorders. The objective of this study was to investigate the clinical response of PDT with the photosensitizing agent 5-aminolevulinic acid (5-ALA) in patients with vulvar intraepithelial neoplasia (VIN) grades 1 to 3. Twenty-five patients with 111 lesions of VIN 1-3 were topically sensitized with 10 ml of a 20% solution of 5-ALA and treated with 57 cycles of laser light at 635 nm (100 J/cm(2)). Seventy (64%) of the 111 VIN lesions regressed after various PDT cycles. A complete response was achieved in 13 patients (52%) with 27 lesions. All patients with VIN 1 and mono- and bifocal VIN 2-3 showed complete clearance. However, a complete response could be achieved in only 4 (27%) of 15 women with multifocal VIN 2-3, whereas a partial response was noted in 9 of these patients with a total of 70 lesions, out of which 44 (63%) lesions disappeared. No response was seen in 2 patients with multifocal VIN 3. Histological assessment of the fluorescence-directed biopsies revealed that increased pigmentation and hyperkeratosis of the lesions were associated with low response rates. PDT using 5-ALA represents an alternative treatment modality for VIN which is easy to perform and has the advantage of minimal tissue destruction, low side effects and excellent cosmetic results. However, multifocal VIN disease with pigmented and hyperkeratinic lesions remains difficult to treat.

Wavelength and fluence effect on vascular damage with photodynamic therapy on skin

Normal skin phototoxicity is clinically predictable during photodynamic therapy with light at 690 and 458 nm wavelengths, in the first 5 h after intravenous bolus infusion of benzoporphyrin derivative mono-acid ring A. This study goal was to determine histologic milestones that lead to tissue necrosis with exposure to red (690 nm) and blue (458 nm) light. The threshold doses for skin necrosis on rabbits were equal at both wavelengths. Lower, equal to, and higher than threshold fluences were delivered in duplicates at hourly intervals, with 40% increments, at constant irradiance. Pathology specimens from irradiated and control sites, were collected at 0, 2, 7, 24, 48 h, and 2 wk after treatment and were paired to equivalent treated sites for clinical evaluation. Immediately after irradiation, at 690 and 458 nm thresholds, light microscopy showed stasis and inflammatory infiltrate in the papillary dermis, respectively; electron microscopy demonstrated pericyte and endothelial cell damage - greater at 690 than 458 nm. At day 1, vascular stasis in the dermis showed a steeper dose-response with red than blue light, and led to necrosis of skin appendages (day 1) and epidermis (days 1-2) at both wavelengths. Sub-threshold fluences induced similar, but significantly milder (p < 0.05) changes and epidermis recovered. Skin necrosis, at threshold fluences in photodynamic therapy with benzoporphyrin derivative mono-acid ring A, was primarily due to vascular compromise to a depth potentially reaching the subcutaneous muscle at 690 nm, whereas at 458 nm vascular damage was confined to upper dermis. This system facilitates selective destruction of skin vasculature, sparing normal epidermis.

Photodynamic therapy in women with cervical intraepithelial neoplasia using topically applied 5-aminolevulinic acid

Photodynamic therapy (PDT) is a novel treatment modality that produces local tissue necrosis with laser light after prior administration of a photosensitizing agent. We performed a study of topically applied 5-aminolevulinic acid (5-ALA) in the photodynamic treatment of women with high-grade cervical intraepithelial neoplasia (CIN) using fixed 5-ALA doses and application protocols derived from previous in vitro and in vivo results. Three to 5 hr prior to PDT, 10 ml of a 20% solution of 5-ALA was topically applied using a cervical cap. PDT was performed with irradiation of 100 J/cm2 at an irradiance of 100-150 mW/cm2 with an argon-ion-pumped dye laser at 635 nm. For the endocervix, a specifically designed cylindrical applicator was used. Ten treatment cycles of PDT using 5-ALA were performed in 7 patients with high-grade CIN. Non-thermal laser treatment with 100-150 mW/cm2 was well tolerated. Local toxicity was minor as several patients reported burning sensations and vaginal discharge, but no necrosis, sloughing or scarring occurred. After 3 months, a significant reduction in the size of the ectocervical CIN lesions was noted in only 3 patients, who underwent a second PDT cycle. However, no significant improvement in CIN lesions was noted since cold knife conization revealed persistent CIN in all 7 cases. Therefore, PDT after topical application of 5-ALA using an irradiation of 100 J/cm2 produces only minimal side effects. However, it does not appear to be effective in treating CIN.