Apoptotic cell death induced by 5-aminolaevulinic acid-mediated photodynamic therapy of hypertrophic scar-derived fibroblasts

Advances in photodynamic therapy of pathologic scar

Pathologic scars include keloids and hypertrophic scars due to abnormal wound healing. Both cause symptoms of itching and pain; they also affect one's appearance and may even constrain movement. Such scars place a heavy burden on the individual's physical and mental health; moreover, treatment with surgery alone is highly likely to leave more scarring. Therefore, there is an urgent need for a treatment that is both minimally invasive and convenient. Photodynamic therapy (PDT) is an emerging safe and noninvasive technology wherein photosensitizers and specific light sources are used to treat malignant tumors and skin diseases. Research on PDT from both the laboratory and clinic has been reported. These findings on the treatment of pathologic scars using photosensitizers, light sources, and other mechanisms are reviewed in the present article.

ALA-PDT promotes the death and contractile capacity of hypertrophic scar fibroblasts through inhibiting the TGF-β1/Smad2/3/4 signaling pathway

BACKGROUND

Hypertrophic scars, an abnormal wound-healing response to burn injuries, are characterized by massive fibroblast proliferation and excessive deposition of extracellular matrix and collagen. 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) is a promising therapy for hypertrophic scar, details of the mechanisms remain to be elucidated. In this study, we aimed to investigate the molecular mechanisms involved in ALA-PDT against hypertrophic scar fibroblasts.

METHODS

The morphologies of hypertrophic scar fibroblasts (HSFs) treated with ALA-PDT were observed under a light microscopy. The viability of HSFs was detected using the CCK-8 assay. HSFs-populated collagen gel contraction assays were conducted to examine the fibroblast contractility and the cytotoxicity of HSFs in 3D collagen tissues were observed using confocal microscopy. The effect of ALA-PDT on TGF-β1/Smad2/3/4 signaling pathway activation and effector gene expression were verified by immunoprecipitation, western blot and real-time quantitative PCR analysis.

RESULTS

We observed significant changes in cell morphology after ALA-PDT treatment of HSFs. As ALA concentration and light dose increased, the viability of HSFs significantly decreased. ALA-PDT can significantly alleviate the contractile capacity and promote the death of HSFs induced by TGF-β1 treatment in a three-dimensional collagen culture model. TGF-β1 treatment of HSFs can significantly induce phosphorylation of Smad2/3 (p-Smad2/3) in whole cells, as well as p-Smad2/3 and Smad4 proteins into the nucleus and increase the mRNA levels of collagen 1/3 and α-SMA. ALA-PDT hampers the TGF-β1-Smad2/3/4 signaling pathway activation by inducing K48-linked ubiquitination and degradation of Smad4.

CONCLUSIONS

Our results provide evidence that ALA-PDT can inhibit fibroblast contraction and promote cell death by inhibiting the activation of the TGF-β1 signaling pathway that mediates hypertrophic scar formation, which may be the basis for the efficacy of ALA-PDT in the treatment of hypertrophic scars.

Indocyanine green based photodynamic therapy for keloids: Fundamental investigation and clinical improvement

BACKGROUND

Keloid, a prevalent pathological skin lesion, presents significant challenges in terms of treatment efficacy. Photodynamic therapy (PDT), an increasingly popular adjuvant treatment, has shown significant potential in the management of various disorders, including cancer. However, the therapeutic potential of indocyanine green-mediated photodynamic therapy (ICG-PDT) for keloids has not yet been demonstrated.

METHODS

In this study, we divided the experimental groups into control group, Photothermal Therapy group, Photodynamic Therapy group, and Combined Therapy group. The in vitro investigation aimed to optimize the clinical application of PDT for keloid treatment by elucidating its underlying mechanism. Subsequently, on this basis, we endeavored to manage a clinical case of keloid by employing surgical intervention in conjunction with modified ICG-PDT.

RESULTS

Our investigation revealed an unexpected outcome that ICG-PDT maximally inhibited the cellular activity and migration of keloid fibroblasts only when photodynamic mechanism took effect. Additionally, the induction of autophagy and apoptosis, as well as the inhibition of collagen synthesis, were particularly evident in this experimental group. Furthermore, the above therapeutic effect could be achieved at remarkably low drug concentrations. Building upon the aforementioned experimental findings, we successfully optimized the treatment modality for the latest case and obtained a more favorable treatment outcome.

CONCLUSIONS

This study investigated the mechanism of ICG-PDT treatment and optimized the in vivo treatment regimen, demonstrating the significant therapeutic potential of ICG-PDT treatment in clinical keloid treatment.

5-ALA-PDT induced ferroptosis in keloid fibroblasts via ROS, accompanied by downregulation of xCT, GPX4

Keloids display many cancerous properties, including uncontrolled and invasive growth, high rates of recurrence as well as similar bioenergetics. 5-aminolevulinic acid-based photodynamic therapy (5-ALA-PDT) is an effective treatment that performs cytotoxic effects by producing reactive oxygen species (ROS), which is linked to lipid peroxidation and ferroptosis. Herein, we explored underlying mechanisms of 5-ALA-PDT against keloids. We identified that 5-ALA-PDT led to elevated levels of ROS and lipid peroxidation in keloid fibroblasts, accompanied by downregulation of xCT and GPX4, which are associated with anti-oxidation effects and ferroptosis inhibition. These results may indicate that 5-ALA-PDT treatment increases ROS while inhibiting xCT and GPX4, thus promoting lipid peroxidation to induce ferroptosis in keloid fibroblasts.

Combination of high-frequency electric with 5-ALA photodynamic therapy in cellular angiofibroma of vulva: A case report

Cellular angiofibroma is a rare benign tumor and difficult to diagnose. Surgery was used in most cases of prior treatment. However, due to the individual differences, this method may be limited, and there is a risk of recurrence. After signing informed consent for treatment, we treated an 18-year-old female with cellular angiofibroma successfully by using the High-Frequency electric pretreatment combined with 5-Aminolevulinic Acid (5-ALA) photodynamic therapy. The tumor was numerous and irregularly shaped on the right labia majora. The specific treatment process was as follows:5-Aminolevulinic Acid (5-ALA) photodynamic therapy was administered after pretreatment with high-frequency electric ion. We did five treatments in total, 10 days apart. And the therapeutic effect was satisfactory for patients. The wound healed well and no recurrence during 12 months follow-up, and the follow-up is continuing. For similar cases, our experience can be taken into account.

5-Aminolevulinic Acid-Hyaluronic Acid Complexes Enhance Skin Retention of 5-Aminolevulinic Acid and Therapeutic Efficacy in the Treatment of Hypertrophic Scar

Hypertrophic scar is a serious skin disorder, which reduces the patient's quality of life. 5-aminolevulinic acid (5-ALA)-mediated photodynamic therapy has been used to treat patients with hypertrophic scar. However, the poor skin retention of 5-ALA limited the therapeutic effect. In this study, we constructed the 5-ALA-hyaluronic acid (HA) complex to potentially prolong the skin retention of 5-ALA for improving the therapeutic efficacy. HA is a polysaccharide with viscoelasticity and the carboxyl groups could conjugate with amino groups of 5-ALA via electrostatic interaction. The protoporphyrin IX (PpIX) assay revealed that 5-ALA-HA complexes markedly enhanced the skin retention, resulting in increased generation and accumulation of endogenous photosensitizer PpIX. Furthermore, 5-ALA-HA complexes allowed PpIX to be maintained at a high level for 12 h, much longer than the 3 h of 5-ALA alone. And then, the accumulative PpIX induced by 5-ALA-HA in human hypertrophic scar fibroblasts (HSF) was triggered by laser irradiation to produce sufficient reactive oxygen species, leading to efficient necrosis and apoptosis of HSF. In vivo therapeutic efficacy study indicated that 5-ALA-HA effectively reduced the appearance and scar thickness, and the scar elevation index with 5-ALA-HA treatment was significantly lower than other groups, suggesting that the 5-ALA-HA-treated scar became flattened and was closely matched to the unwounded tissues. Moreover, 5-ALA-HA treatment markedly downregulated the gene expression levels of α-SMA and TGF-β1, demonstrating attenuated the scar formation and growth. Therefore, the 5-ALA-HA complex enhancing skin retention and PpIX accumulation at the lesion site provide a promising therapeutic strategy for hypertrophic scar.

Evaluating the efficacy of photodynamic therapy with indocyanine green in the treatment of keloid

BACKGROUND

This study aimed to evaluate the efficacy of photodynamic therapy (PDT) with topical indocyanine green (ICG) in the treatment of keloid lesions.

METHODS

In this pilot study, fifteen keloids (6 lesions on the sternal area, 3 on the shoulders, 2 on the abdomen, 2 on the legs, and 2 on the forearms) were selected. To enhance drug penetration, pretreatment with CO2 laser was performed. Then Lesions were covered with 0.2% transfersomal ICG gel with 1mm thickness and occluded with light-proof plastic nylon for 2 hours. Afterward, it was wiped off and underwent photodynamic therapy with source LumaCare with 730 nm probe and fluence of 23 J/cm2 every week for 6 sessions. Patients were also assessed 6 and 12 weeks after the treatment for any recurrences. The Patient and Observer Scar Assessment Scale (POSAS) was used to evaluate the scars.

RESULTS

The mean POSAS score significantly reduced by 23.69% from 46.86 at baseline to 35.76 at the 6^th treatment session (P< 0.001). The mean scores of patient and observer overall opinion significantly decreased by 16.35% (P< 0.001) and 12.31 % (P= 0.001) respectively. No side effects were observed during treatment and after 3 months of follow-ups. After discontinuation of therapy, the mean score of POSAS significantly increased by 13.77% to 40.80. (P= 0.001) CONCLUSION: : According to our study, ICG-PDT is an effective and safe treatment for keloid. However, due to the recurrence following discontinuation of treatment, further studies are needed.

A clinical study of carbon dioxide lattice laser-assisted or microneedle-assisted 5-aminolevulinic acid-based photodynamic therapy for the treatment of hypertrophic acne scars

OBJECTIVE

To study the clinical efficacy, recurrence rate and safety of 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) combined with microneedle or CO2 lattice laser (CO2FL), in comparison with intrascar betamethasone injection in the treatment of hypertrophic acne scar.

METHODS

Fifty-two patients with hypertrophic acne scars at the mandibular angle were enrolled and assigned to different therapy groups. Sixteen patients were treated with microneedle-assisted incorporation of ALA. Twenty-eight patients underwent CO2FL-assisted incorporation of ALA. Eight patients received standard therapy with intrascar injection of glucocorticoid. Two dermatologists, blinded to the therapy groups, independently evaluated the scars in all patients using the average value of the Vancouver Scar Scale score, which was treated as an integer variable.

RESULTS

After three rounds of treatment, there was no significant difference in therapeutic effective rate among the microneedle, laser and topical glucocorticoid groups (93.75% vs 100% vs 100%, P = .855). One out of 16 patients (6.25%) in the microneedle group, no patient (0%) in the laser group and two out of eight patients (25%) in the topical glucocorticoid group had recurrence. The laser group showed a higher rate of adverse effects, which were usually mild and reversible, except for pigmentation. Adverse reactions could be completely subsided within 3 weeks.

CONCLUSIONS

Either CO2FL or microneedle combined ALA-PDT for hypertrophic scar, as to topical glucocorticoid therapy, showed equivalent clinical effects but lower recurrence rate within 6 months of follow-up period.

Synergistic transdermal delivery of nanoethosomes embedded in hyaluronic acid nanogels for enhancing photodynamic therapy

Photodynamic therapy (PDT) is a new therapeutic strategy for hypertrophic scars (HS), but it is limited by low drug utilization. Transdermal delivery based on nanoethosomes (ES) has attracted considerable attention as a potential clinical strategy in PDT treating HS. However, free ES are unsatisfactory due to their instability and non-targeting, which causes non-effective delivery and low drug utilization. Herein, 5-aminolevulinic acid (ALA)-loaded ES (ES-ALA) embedded in hyaluronic acid (HA) meshes (HA/ES-ALA), a novel synergistic transdermal delivery nanogel, are developed for enhancing PDT of HS. HA/ES-ALA has a unique structure and property to protect unilaminar ES-ALA with HA meshes and actively target hypertrophic scar fibroblasts (HSFs) with HA receptors. Both in vitro and in vivo experiments demonstrate that HA/ES-ALA has a remarkable transdermal delivery ability with penetrating channels and a membrane-fusion mechanism. Meanwhile, the synergistic delivery mechanism is visually characterized as three stages: synergistic penetration, targeting aggregation and transmembrane delivery. With the synergistic effect, HA/ES-ALA can realize a targeted transdermal delivery, and significantly improve ALA utilization and enhance PDT efficacy. The results demonstrate an effective transdermal delivery route to enhance therapy for HS as well as other skin diseases.

Design of new protein drug delivery system (PDDS) with photoactive compounds as a potential application in the treatment of glioblastoma brain cancer

Glioblastoma multiforme (GBM) is an extremely aggressive malignant brain tumor. Despite advances in treatment modalities, it remains largely incurable. This unfavorable prognosis for GBM is at least partly due to the lack of a successful drug delivery system across the blood-brain barrier (BBB). The delivery of drugs through nanomedicines combined with less invasive alternative therapies represents an important hope for the future of these incurable brain tumors. Whey protein nanocarriers represent promising strategy for targeted drug delivery to tumor cells by enhancing the drug's bioavailability and distribution, and reducing the body's response towards drug resistance. They have been extensively studied to find new alternatives for capacity to encapsulate different drugs and no need for cross-linkers. In this study, we report for the first time the incorporation and administration of Aluminum phthalocyanine chloride (AlClPc)-loaded whey protein drug delivery system (AlClPc-PDDS) for the treatment of glioblastoma brain cancer. This system was designed and optimized (with the use of the spray drying technique) to obtain the required particle size (in the range of 100 to 300 nm), zeta potential and drug loading. Our results suggest that we have developed a drug delivery system from a low-cost raw material and preparation method that is capable of incorporating hydrophobic drugs which, in combination with irradiation, cause photodamage to neoplasic cells, working as an effective adjuvant treatment for malignant glioma.

Photodynamic therapy for keloids and hypertrophic scars: a review

PURPOSE

Keloid is a poorly understood disease that is unique to humans. Hypertrophic scars are similar to keloids and may transform into keloids over time. The standard treatments for these scars are limited by inconsistent efficacy and long treatment/follow-up times. Therefore, a new treatment that is effective for all abnormal scar cases is needed. One option may be photodynamic therapy (PDT). This review assesses the current evidence regarding the safety and efficacy of PDT for keloids and hypertrophic scars.

METHODS

PubMed, Medline and Web of Science were searched from 1900 onwards for the following terms: 'keloid and photodynamic therapy (PDT)'; 'hypertrophic scar and photodynamic therapy (PDT)'; and 'scar and photodynamic therapy (PDT)'. Articles were included if they reported using topical PDT to treat keloids or hypertrophic scars, the patient(s) had one or more keloids and/or hypertrophic scars, and the effect of PDT on these abnormal scars was described.

RESULTS

In total, 538 articles were identified. Thirteen fulfilled all inclusion criteria. Eight were laboratory studies on keloid/hypertrophic scar explants, fibroblasts or tissue-engineered skin models and five were clinical studies/case reports. The clinical results of PDT on keloids and hypertrophic scars are encouraging.

CONCLUSION

PDT appears to play a promising role in keloid and hypertrophic scar therapy but additional clinical studies, particularly randomised clinical trials, are needed.

Transdermal Delivery of 5-Aminolevulinic Acid by Nanoethosome Gels for Photodynamic Therapy of Hypertrophic Scars

5-Aminolevulinic acid (ALA)-loaded nanoethosome (ALA-ES) gels are successfully prepared to realize a transdermal delivery of ALA, and they provide a feasible approach for the photodynamic therapy (PDT) of hypertrophic scars (HS). Herein, the morphological and physicochemical features indicate that ALA-ES is stable in gel matrix. In vitro transdermal penetration studies suggest ALA-ES gels can overcome the compact dermal barrier and deliver more ALA into human HS tissue. In vivo delivery studies further reveal that ALA-ES gels can penetrate into rabbit HS tissue to facilitate ALA accumulating in hypertrophic scar fibroblast (HSF) and converting into protoporphyrin IX in the cytoplasm. Utilizing transmission electron microscopy, the visual in vivo penetration process indicates ALA-ES penetrate into HS tissue utilizing its deformable membrane, enters HSF by a pinocytotic-like mechanism, and then releases ALA in the cytoplasm. Subsequently, PDT efficacy is assessed using rabbit HS models. The morphological and histological analysis reveal that ALA-ES gels can improve HS by promoting HSF apoptosis, remodelling collagen fibers and increasing MMP3 expression. The results demonstrate that ALA-ES gels are suitable in clinical treatment of HS and make a substantial progress within the field.

Efficacy of 5-aminolevulinic acid-based photodynamic therapy against keloid compromised by downregulation of SIRT1-SIRT3-SOD2-mROS dependent autophagy pathway

Keloids exhibit cancer-like properties without spontaneous regression and usually recur post excision. Although photodynamic therapy (PDT) is a promising treatment, details of the mechanisms remain to be elucidated. In this study, we investigated mechanisms involved in 5-Aminolevulinic Acid (5-ALA)-based PDT against keloid. Found that 5-ALA-PDT induced superoxide anion-dependent autophagic cell death. Application of autophagy inhibitor 3-Methyladenine (3-MA) significantly prevented the effect that 5-ALA-PDT induced keloid-derived fibroblasts death, but Z-VAK-FMK (apoptotic inhibitor) did not. Interestingly, 5-ALA-PDT promoted the SIRT3 protein expression and the activity of mitochondrial superoxide dismutase 2 (SOD2), but SIRT1 protein expression level was decreased. SOD2 as a key enzyme can decrease mitochondrial ROS (mROS) level, Deacetylation of SOD2 by SIRT3 regulates SOD2 enzymatic activity has been identified. Then we explored SOD2 acetylation level with immunoprecipitation, found that 5-ALA-PDT significantly increased the acetylation levels of SOD2. In order to confirm deacetylation of SOD2 regulated by SIRT3, 3-TYP (SIRT3 inhibitor) was used. Found that inhibition of SIRT3 by 3-TYP significantly increased the level of SOD2 acetylation level compared with control group or 5-ALA-PDT group. To explore the connection of SIRT1 and SIRT3, cells were treated with EX527(SIRT1 inhibitor) or SRT1720 (SIRT1 activator), and EX527 increased SIRT3 protein level, however, SRT1720 displayed the opposite effect in the present or absence of 5-ALA-PDT. Moreover SIRT1-inhibited cells are more resistant to 5-ALA-PDT and showing decreased ROS accumulation. These results may demonstrate that 5-ALA-PDT induced SIRT1 protein level decreased, which promoted the effect of SIRT3 increased activity of SOD2 that can reduce mROS level, and then compromised 5-ALA-PDT induced autophagic cell death.

Photodynamic therapy in dermatology beyond non-melanoma cancer: An update

Photodynamic therapy (PDT) employs a photosensitizer (PS) and visible light in the presence of oxygen, leading to production of cytotoxic reactive oxygen species, which can damage the cellular organelles and cause cell death. In dermatology, PDT has usually taken the form of topical application of a precursor in the heme biosynthesis pathway, called 5-aminolevulinic acid (or its methyl ester), so that an active PS, protoporphyrin IX accumulates in the skin. As PDT enhances dermal remodeling and resolves chronic inflamation, it has been used to treat cutaneous disorders include actinic keratoses, acne, viral warts, skin rejuvenation, psoriasis, localized scleroderma, some non-melanoma skin cancers and port-wine stains. Efforts are still needed to mitigate the side effects (principally pain) and improve the overall procedure.

5-Aminolevulinic acid loaded ethosomal vesicles with high entrapment efficiency for in vitro topical transdermal delivery and photodynamic therapy of hypertrophic scars

Photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) is an alternative therapy for hypertrophic scars (HS), which destroys human hypertrophic scar fibroblasts (HSF). However, the poor permeability of ALA both in HS tissue and HSF significantly restricts the PDT of HS. To overcome these barriers, ALA-loaded ethosomal vesicles (ALA-ES) were developed by a pH gradient active loading method and characterized by morphology, entrapment efficiency (EE) and stability. Results show that prepared ALA-ES are homogenous spherical lamellar vesicles, 53 ± 7 nm in size, 50.6 ± 2.3% in EE and have excellent stability. In vitro transdermal delivery studies through HS tissue were carried out by using Franz diffusion cells. Compared to the traditional ALA hydroalcoholic solution (ALA-HA), ALA-ES achieve higher drug retention in less administration time, and fluorescence microscopy showed that ALA-ES penetrate into the deeper dermis of HS in a shorter time, indicating that ALA-ES can enhance the penetration of ALA into HS. Additionally, ALA-ES was visualized in HS tissue for the first time by transmission electron microscopy (TEM). The irregular and collapsed ALA-ES suggest that they can squeeze through narrow spaces to the target area and release ALA into HS. Taking HSF as the target, the transcellular delivery of ALA-ES into HSF cells was investigated by intracellular protoporphyrin IX (PpIX) accumulation. The efficiency of PDT for HSF cells, including the formation of reactive oxygen species (ROS) and cell apoptosis, were also well investigated. Furthermore, the detailed changes of HSF were observed by TEM. The results strongly indicate that ALA-ES can facilitate ALA penetration into HSF cells, and can cause a higher level of cell apoptosis or necrosis than ALA-HA. ALA-ES with high EE is therefore a promising transdermal delivery system for topical ALA administration and has great potential in ALA-PDT of HS.

Therapeutic effects of topical 5-aminolevulinic acid photodynamic therapy

Objective:

To evaluate the therapeutic effects of combined 5-aminolevulinic acid (ALA) and photodynamic therapy (PDT) on genital warts and the safety.

Methods:

One hundred ten patients with genital warts who were treated in our hospital from June 2013 to October 2014 were selected. The warts and affected parts were disinfected with benzalkonium bromide solution, and the warts were covered with absorbent cotton that had already been added freshly prepared 20% ALA solution, packaged and fixed. Then they were wet-dressed in dark, into which ALA solution was added according to the proportion of 5:3:2 every 30 minutes for three consecutive hours. Afterwards, the warts were illuminated by using photodynamic laser apparatus. The clinical outcomes, adverse reactions and recurrence rates were observed.

Results:

Genital warts were relieved in 107 out of the 110 cases (cure rate: 97.3%). Male patients had significantly better treatment outcomes at the urethral orifice than those in other affected parts. In the 107 patients, the cure rate of male patients was 98.8%, and they were cured after being treated four times. In contrast, female patients, who were cured after 5 times of treatment, had the cure rate of 91.7%. Their cure rates were similar (χ²=0, P>0.05), but the males were cured after significantly fewer times of treatment than the females (t=-7.432, P<0.05). Five patients suffered from mild tingling or burning sensation upon dressing at the urethral orifice, and the others were all free from systemic adverse reactions. After illumination, a small portion of the patients had mildly red, swelling, painful affected parts, with mild edema that almost disappeared within three days. Three patients relapsed at the urethral orifice and were then cured after further treatment.

Conclusion:

ALA-PDT can treat genital warts safely with high cure rate and low recurrence rate, particularly working for those of males at the urethral orifice.

Cyclometalated iridium(iii) complexes as lysosome-targeted photodynamic anticancer and real-time tracking agents

We report the rational design and photodynamic anticancer mechanism studies of iridium(iii) complexes with pH-responsive singlet oxygen (¹O₂) production and lysosome-specific imaging properties.

Stimuli-activatable photosensitizers (PSs) are highly desirable for photodynamic therapy (PDT) to selectively demolish tumor cells. On the other hand, lysosomes are emerging as attractive anticancer targets. Herein, four cyclometalated iridium(iii)–β-carboline complexes with pH-responsive singlet oxygen (¹O₂) production and lysosome-specific imaging properties have been designed and synthesized. Upon visible light (425 nm) irradiation, they show highly selective phototoxicities against cancer cells. Notably, complex 2 ([Ir(N^C)₂(N^N)](PF₆) in which N^C = 2-phenylpyridine and N^N = 1-(2-benzimidazolyl)-β-carboline) displays a remarkably high phototoxicity index (PI = IC₅₀ in the dark/IC₅₀ in light) of >833 against human lung carcinoma A549 cells. Further studies show that 2-mediated PDT induces caspase-dependent apoptosis through lysosomal damage. The pH-responsive phosphorescence of complex 2 can be utilized to monitor the lysosomal integrity upon PDT, which provides a reliable and convenient method for in situ monitoring of therapeutic effect and real-time assessment of treatment outcome. Our work provides a strategy for the construction of highly effective multifunctional subcellular targeted photodynamic anticancer agents through rational structural modification of phosphorescent metal complexes.

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.

Aminolevulinic acid (ALA): photodynamic detection and potential therapeutic applications

Aminolevulinic acid (ALA) is a heme precursor that may have potential applications for photodynamic detection and photodynamic therapy-based treatment of solid tumors in a variety of malignancies. ALA may have a role in other applications in surgical oncology based on its ability to discriminate neoplastic tissue from adjacent normal tissue. In this review, we provide a comprehensive summary of the published studies of ALA in noncutaneous solid malignancies.