Kate Cristina Blanco

Fluorescence guided PDT for optimization of the outcome of skin cancer treatment

The photodynamic therapy (PDT) is an alternative technique that can be indicated for superficial basal cell carcinoma (sBCC), Bowen’s disease and actinic keratosis with high efficiency. The objective of this study is to present the importance of fluorescence imaging for PDT guidance and monitoring in real time. Confirming that the lesion is well prepared and the photosensitizer shows a homogenous distribution, the outcome after few PDT sessions will be positive and the recurrence should be lower. Our proposition in this study is use the widefield fluorescence imaging to evaluate the PDT protocol in situ and in real time for each lesion. This evaluation procedure is performed in two steps: first with the monitoring of the production of protoporphyrin IX (PpIX) induced by methyl aminolevulinate (MAL), an derivative of 5-aminolevulinic acid (ALA) and second with the detection of PpIX photobleaching after illumination. The fluorescence images provide information correlated with distinct clinical features and with the treatment outcome. Eight BCC lesions are presented and discussed in this study. Different fluorescence patterns of PpIX production and photobleaching could be correlated with the treatment response. The presented results show the potential of using widefield fluorescence imaging as a guidance tool to customized PDT.

Photodynamic inactivation of contaminated blood with Staphylococcus aureus

The presence of bacteria in the bloodstream can trigger a serious systemic inflammation and lead to sepsis that cause septic shock and death. Studies have shown an increase in the incidence of sepsis over the years and it is mainly due to the increased resistance of microorganisms to antibiotics, since these drugs are still sold and used improperly. The bacterial contamination of blood is also a risk to blood transfusions. Thus, bacteria inactivation in blood is being studied in order to increase the security of the blood supply. The purpose of this study was to decontaminate the blood using the photodynamic inactivation (PDI). Human blood samples in the presence of Photogem® were illuminated at an intensity of 30 mW/cm2, and light doses of 10 and 15 J/cm2. Blood counts were carried out for the quantitative evaluation and blood smears were prepared for qualitative and morphological evaluation by microscopy. The results showed normal viability values for the blood cells analyzed. The light doses showed minimal morphological changes in the membrane of red blood cells, but the irradiation in the presence of the photosensitizer caused hemolysis in red blood cells at the higher concentrations of the photosensitizer. Experiments with Staphylococcus aureus, one of the responsible of sepsis, showed 7 logs10 of photodynamic inactivation with 50 μg/mL and 15 J/cm2 and 1 log10 of this microorganism in a co-culture with blood.

Adapting smartphones for low-cost optical medical imaging

Optical images have been used in several medical situations to improve diagnosis of lesions or to monitor treatments. However, most systems employ expensive scientific (CCD or CMOS) cameras and need computers to display and save the images, usually resulting in a high final cost for the system. Additionally, this sort of apparatus operation usually becomes more complex, requiring more and more specialized technical knowledge from the operator. Currently, the number of people using smartphone-like devices with built-in high quality cameras is increasing, which might allow using such devices as an efficient, lower cost, portable imaging system for medical applications. Thus, we aim to develop methods of adaptation of those devices to optical medical imaging techniques, such as fluorescence. Particularly, smartphones covers were adapted to connect a smartphone-like device to widefield fluorescence imaging systems. These systems were used to detect lesions in different tissues, such as cervix and mouth/throat mucosa, and to monitor ALA-induced protoporphyrin-IX formation for photodynamic treatment of Cervical Intraepithelial Neoplasia. This approach may contribute significantly to low-cost, portable and simple clinical optical imaging collection.

Reduced methicillin-resistant Staphylococcus aureus biofilm formation in bone cavities by photodynamic therapy

Photodynamic Therapy (PDT) is a promising alternative for the treatment of infectious bone lesions in the oral cavity. The objective of this study was to evaluate the antimicrobial effectiveness of PDT using blue LED associated with curcumin in methicillin-resistant Staphylococcus aureus biofilms (MRSA) in bovine bone cavities by fluorescence spectroscopy. Standardized suspensions of MRSA culture were inoculated into bone lesions to form biofilm. Forty bone species were distributed in three distinct groups: L-C- (control); L + C- (LED for 5 min); L-C+ (curcumin incubation for 5 min) and L + C+ (PDT). Aliquots of 100 μL were collected from the bone cavities after the treatments and were cultived in BHI for 24 h at 36 °C ± 1 and bacterial colonies counting were performed. Statistical analysis were performed using the paired t-test and analysis of variance (ANOVA) for the variables studied. RESULTS The control and PDT groups presented statistically significant differences (p < 0.001). It was possible to reduce 3.666 log10 CFU/mL of MRSA and a reduction in the fluorescence emitted after the treatments was observed. The MRSA reduction in biofilms by PDT was the most efficient treatmnent. There was a significant reduction of biofilms in the L + C- and non-PDT groups by fluorescence spectroscopy images.

Optical techniques for the diagnosis and treatment of lesions induced by the human papillomavirus — A resource letter

Human papillomaviruses (HPV) are the most common sexually-transmitted virus, and carcinogenic HPV strains are reported to be responsible for virtually all cases of cervical cancer and its precursor, the cervical intraepithelial neoplasia (CIN). About 30% of the sexually active population are considered to be affected by HPV. Around 600 million people are estimated to be infected worldwide. Diseases related to HPV cause significant impact from both the personal welfare point of view and public healthcare perspective. This resource letter collects relevant information regarding HPV-induced lesions and discusses both diagnosis and treatment, with particular attention to optical techniques and the challenges involved to the implementation of those approaches.

Biofilm Destruction on Endotracheal Tubes by Photodynamic Inactivation

BACKGROUND Hospital infections are a public health problem that can occur with the use of catheters and endotracheal tubes (ETT). Pathogenic microorganisms may adhere to surfaces of these materials forming a biofilm and produce an extracellular polymer matrix that promotes resistance of microorganisms to factors such as pH, temperature and drugs. The conventional treatment is being made by antibiotics, which has serious adverse effects in immunocompromised patients. Photodynamic therapy (PDT) is an alternative for microbial inactivation noninvasive without the stimulus of microbial resistance. PDT combines light and a photosensitive molecule for produce reactive oxygen species leading to bacterial death. OBJECTIVE The objective of this study was to determine the efficacy of a PDT protocol in bacterial inactivation of biofilm ETT. METHOD The photosensitizer (PS) used was curcumin and the light source LED at 450nm. A statistical experimental design was used for optimization of antimicrobial PDT. RESULTS The highest microbial inactivation was observed with 70% biofilm reduction in conditions 1.25 mg/mL curcumin, 2 h of PS incubation and 50 J/cm2. CONCLUSION This study described the photodynamic death of bacteria forming a biofilm on ETT. Parameters optimization was important for clinical application of this system.

PDT, an Adjuvant Therapy to Antibiotic Failure in Streptococcal Tonsillopharyngitis

In the last decades, the emergence and spread of antimicrobial resistance bacteria has been viewed. Multidrug resistant bacteria are currently considered agents of worldwide emerging diseases and thus an important public health problem. Coordinated efforts to develop new therapeutic strategies are necessary. Photodynamic therapy (PDT) is a therapeutic modality based in photochemical and photophysical processes. PDT has been shown to be effective in bacterial lysis and safe in oral cavity for oral disinfection [1,2]. We report a clinical case of recurrent pharyngotonsillitis (FT) in presence of microorganisms that did not respond to antibiotic treatment. The PDT was applied in three sessions in two steps: application of pharmaceutical formulations containing 0.75 mg/mL curcumin and illumination at 450 nm and 6.57 J/cm2. It was concluded that the PDT may be used as treatment in cases of antibiotic failure. In addition, periodically the PDT may be applied in case of recurrent pharyngitis.

PDT and emerging therapies for Actinic Keratosis—A resource letter

Aktinic Keratosis is common and if left untreated may develop into life threatening squamous cell carcinoma. Therefore early intervention is the standard of care. While many treatments are available PDT continues to move to the for - front for this indication (Brito et al., 2016 [31]). Topical PS is commercially available that are able to reliably ablate these lesions. Innovative protocols including sunlight, large volume LED arrays and maneuvers to improve treatment parameters and cosmesis continue to make this a worldwide treatment of choice for AK.

Antimicrobial Efficacy of Curcumin Formulations by Photodynamic Therapy

URTI (upper respiratory tract infections) are caused by acute, chronic or recurrent infections including pharyngitis and tonsillitis. The etiologic agents involved are bacteria, virus, and fungi. The standard treatment for bacterial infections is the use of antibiotics. The antibiotic resistance, side effects of drugs and URTI complications indicate the importance of new therapies. PDT (photodynamic therapy) is a treatment option with a fast onset of action, low side effects, and easy administration of PS (photosensitizer) based on this study. The main aim of this study was to develop a new modality for the treatment of infectious pharyngotonsillitis by photodynamic therapy. In addition, this study aims to evaluate components of the therapy as the PS, curcumin, in two formulations and irradiation conditions in the effectiveness of treatment. The procedure consists of two steps: oral administration of CFs (curcumin formulations) containing a PS and illumination (450 nm and 0-60 J/cm). Bacterial isolates were obtained from patients in a routine clinical pratice. The new methodology has been developed from the principle of PI (photodynamic inactivation). The strain identification number of colony forming units determined the efficacy of PI using each component, lighting and PS. The use of curcumin formulations in PI presented microbial reduction of 5 log.

Photodynamic Therapy for the Treatment of Skin Cancer in Patients with Idiopathic Thrombocytopenia: A Case Report

Idiopathic Thrombocytopenia (IT) is an autoimmune disease in which the patients present a reduction of blood platelets, increasing the risk of bleeding and its complications. Especially, elderly patients those with neoplasia associated to idiopathic thrombocytopenia are more likely to severe risks of bleeding. Here were report a case of an eighty-year-old man with diagnosis of idiopathic thrombocytopenia and confirmed biopsy of nodular basal cell carcinoma (nBCC) located on the nose. The use of the standard treatment surgery was not carried in this case due to risks generated by autoimmune disease. Photodynamic Therapy (PDT) was indicated as an adjuvant therapy associated to shaving and electrocoagulation providing elimination of recent cancer cells. This PDT is an alternative for the treatment of modular basal cell carcinoma no greater than 2 cm of diameter and small depth. The patient was treated with shaving, electrocoagulation and topical PDT using 20% methyl aminolevulinate (MAL) and fluency of 150 J/cm2 with 630 nm light. This adjuvant treatment of nodular BCC is minimally invasive and can be indicated to patients with surgical risks, and that is the importance for this report. The success of this case is an important precedent for thousands of patients’ with similar conditions.