Ornithine aspartate effects on bacterial composition and metabolic pathways in a rat model of steatotic liver disease.

BACKGROUND: Metabolic-dysfunction associated steatotic liver disease (MASLD) is a hepatic manifestation of metabolic syndrome. Studies suggest ornithine aspartate (LOLA) as drug therapy. AIM: To analyze the influence of LOLA intake on gut microbiota using a nutritional model of MASLD. METHODS: Adult male Sprague Dawley rats were randomized into three groups: Control (10 rats fed with a standard diet), MASLD (10 rats fed with a high-fat and choline-deficient diet), and LOLA (10 rats receiving 200 mg/kg/d LOLA, after the 16th week receiving high-fat and choline-deficient diet). After 28 wk of the experiment, animals were euthanized, and feces present in the intestine were collected. Following fecal DNA extraction, the V4 region of the 16S rRNA gene was amplified followed by sequencing in an Ion S5™ system. RESULTS: Alpha and beta diversity metrics were comparable between MASLD and LOLA. 3 OTUs were differentially abundant between MASLD and LOLA, which belong to the species Helicobacter rodentium, Parabacteroides goldsteinii, and Parabacteroides distasonis. The functional prediction provided two different metabolic profiles between MASLD and LOLA. The 9 pathways differentially abundant in MASLD are related to a change in energy source, adenosine/purine nucleotides degradation as well as guanosine and adenosine deoxyribonucleotides biosynthesis. The 14 pathways differentially abundant in LOLA are associated with four major metabolic functions primarily influenced by L-aspartate, including tricarboxylic acid cycle pathways, purine/guanosine nucleotides biosynthesis, pyrimidine ribonucleotides biosynthesis and salvage as well as lipid IVA biosynthesis. CONCLUSION: Although LOLA had no influence on alpha and beta diversity in this nutritional model of MASLD, it was associated with changes in specific gut microbes and their related metabolic pathways.

Ornithine Aspartate and Vitamin-E Combination Has Beneficial Effects on Cardiovascular Risk Factors in an Animal Model of Nonalcoholic Fatty Liver Disease in Rats.

Cardiovascular (CV) disease is the main cause of death in nonalcoholic fatty liver disease (NAFLD), a clinical condition without any approved pharmacological therapy. Thus, we investigated the effects of ornithine aspartate (LOLA) and/or Vitamin E (VitE) on CV parameters in a steatohepatitis experimental model. Adult Sprague Dawley rats were randomly assigned (10 animals each) and treated from 16 to 28 weeks with gavage as follows: controls (standard diet plus distilled water (DW)), NAFLD (high-fat choline-deficient diet (HFCD) plus DW), NAFLD+LOLA (HFCD plus LOLA (200 mg/kg/day)), NAFLD+VitE (HFCD plus VitE (150 mg twice a week)) or NAFLD+LOLA+VitE in the same doses. Atherogenic ratios were higher in NAFLD when compared with NAFLD+LOLA+VitE and controls (p < 0.05). Serum concentration of IL-1ß, IL-6, TNF-α, MCP-1, e-selectin, ICAM-1, and PAI-1 were not different in intervention groups and controls (p > 0.05). NAFLD+LOLA decreased miR-122, miR-33a, and miR-186 (p < 0.05, for all) in relation to NAFLD. NAFLD+LOLA+VitE decreased miR-122, miR-33a and miR-186, and increased miR-126 (p < 0.05, for all) in comparison to NAFLD and NAFLD+VitE. NAFLD+LOLA and NAFLD+LOLA+VitE prevented liver collagen deposition (p = 0.006) in comparison to NAFLD. Normal cardiac fibers (size and shape) were lower in NAFLD in relation to the others; and the inverse was reported for the percentage of regular hypertrophic cardiomyocytes. NAFLD+LOLA+VitE promoted a significant improvement in atherogenic dyslipidemia, liver fibrosis, and paracrine signaling of lipid metabolism and endothelial dysfunction. This association should be further explored in the treatment of NAFLD-associated CV risk factors.

Understanding the mechanism of action of peptide (p-BthTX-I)2 derived from C-terminal region of phospholipase A2 (PLA2)-like bothropstoxin-I on Gram-positive and Gram-negative bacteria.

Based on the antimicrobial activity of bothropstoxin-I (BthTX-I) and on the premise that a C-terminal peptide of Lys49 myotoxin can reproduce the antimicrobial activity of the parent protein, we aimed to study the mechanism of action of a peptide derived from the C-terminal region of the myotoxin BthTX-I [(p-BthTX-I)2, sequence: KKYRYHLKPFCKK, disulfide-linked dimer] against Gram-positive and Gram-negative bacteria. Fluorescence quenching technique showed that the carboxyfluorescein labeled-peptide [CF-(p-BthTX-I)2] when incubated with E. coli displayed a superior penetration activity than when incubated with S. aureus. Cell death induced by the peptide (p-BthTX-I)2 showed a loss of membrane integrity in E. coli and S. aureus; however, the mechanisms of cell death were different, characterized by the presence of necrosis-like and apoptosis-like deaths, respectively. Scanning electron microscopy studies in E. coli and S. aureus showed morphological changes in the cells, with superficial deformities, appearance of wrinkles and bubbles, and formation of vesicles. Our results demonstrate that the mechanism of action of the peptide (p-BthTX-I)2 is different in Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. Knowledge of the mechanism of action of these peptides is important, since they are promising prototypes for new antimicrobial drugs.

ORTHOPEDIC RELATED COMORBIDITIES IN SPINAL CORD-INJURED INDIVIDUALS.

OBJECTIVE: This study aims to review, identify and study the determinations of the main orthopedic aspects in SCI patients. METHODS: A total of 80 articles from PUBMED and three theses (MSc. /DSc.) were examined. RESULTS: The results refer to the most essential joints. There is a chronic overload on the shoulder girdle due to the use of the upper limb as a supporting joint. The elbow presents osteoarthritis, subclinical, acute and chronic pain, mainly in quadriplegic patients. In the hand and wrist joints there are cases of paralysis, osteoporosis and osteoarthritis. Hips are the main weight-bearing joints while sitting which leads to a substantial degenerative process of this joint. Lastly, on the knee, feet and ankles, spasticity, contractures, osteoporosis and deformities can arise. CONCLUSION: Along with the increase in cases and research that analyze the alterations that spinal cord-injured individuals suffer, it is necessary to recognize the orthopedic changes to understand their limits and identify the relevance of the rehabilitation program to improve the muscle performance. Level of Evidence II, Prognostic Studies - Investigating the Effect of a Patient Characteristic on the Outcome of Disease.

OBJETIVO: O objetivo do estudo foi identificar, através de uma revisão sistemática, os aspectos ortopédicos e suas determinações nos pacientes lesados medulares. MÉTODOS: Foram examinados 80 artigos na base Pubmed e três teses de mestrado e doutorado. RESULTADOS: Os resultados obtidos referem-se às principais articulações. No ombro há uma sobrecarga crônica na cintura escapular devido ao uso como articulação de suporte. O cotovelo apresenta alterações osteocartilaginosas e dores subaguda, aguda e crônica principalmente no paciente tetraplégico. Nas articulações da mão e punho, a lesão leva à perda da capacidade de compressão por paralisia, osteoporose e osteoartrite. O quadril constitui a principal articulação de sustentação de peso quando sentado, ocorrendo um processo degenerativo importante nesses pacientes. Nos joelhos, pés e tornozelos surgem espasticidade, contraturas e osteoporose levando a deformidades. CONCLUSÃO: Devido ao aumento de casos e de pesquisas que analisam as alterações que os lesados medulares sofrem, se faz necessário o conhecimento das alterações ortopédicas do lesado medular para compreendermos a sua limitação e identificar a relevância do programa de reabilitação para melhora da performance muscular. Nível de Evidência II, Estudos Prognósticos - Investigação do efeito de característica de um paciente sobre o desfecho da doença.

Influence of light intensity and irradiation mode on methylene blue, chlorin-e6 and curcumin-mediated photodynamic therapy against Enterococcus faecalis.

This study aimed to evaluate the effect of the continuous irradiation with low intensity (continuous mode) and fractioned irradiation with high intensity (fractionated mode), keeping the same dose of light by using Light Emitting Diode (LEDs) with wavelength emission centered at 450 and at 660 nm, using methylene blue (MB), chlorin-e6 (Ce6) and curcumin (CUR) as photosensitizers (PSs) against planktonic phase of E. faecalis. Cell viability was assessed by counting colonies forming per mL (CFU/mL), and the quantification of reactive species was performed by fluorescence with the photodegradation rate evaluated by measurements of absorbance of PSs at different times. The results revealed that MB-mediated PDT was efficient to achieve total microbial load reduction in both irradiation modes, but in fractional mode it was possible to use a lower light dose. Using Ce6, a total bacterial reduction was observed when fractional light was used, but at the same light dose, there was no reduction in the continuous irradiation mode. CUR-mediated PDT under continuous irradiation mode promoted the total microbial load reduction. However, for fractional mode, a higher concentration of CUR was required to completely reduce E. faecalis cell viability. Our results suggest that the biological response to PDT is variable depending on the irradiation mode and on the photosensitizer. Therefore, these studies indicate that the irradiation mode, intensity and the specific PSs should be taken into account for the development of clinical protocols for PDT.

Phthalocyanine-loaded nanostructured lipid carriers functionalized with folic acid for photodynamic therapy.

Breast cancer is a serious public health problem that causes thousands of deaths annually. Chemotherapy continues to play a central role in the management of breast cancer but is associated with extreme off-target toxicity. Therefore, treatments that directly target the tumor and display reduced susceptibility to resistance could improve the outcome and quality of life for patients suffering from this disease. Photodynamic therapy is a targeted treatment based on the use of light to activate a photosensitizer (PS) that then interacts with molecular oxygen and other biochemical substrates to generate cytotoxic levels of Reactive Oxygen Species. Currently approved PS also tends to have poor aqueous solubility that can cause problems when delivered intravenously. In order to circumvent this limitation, in this manuscript, we evaluate the potential of a phthalocyanine-loaded nanostructured lipid carrier (NLC) functionalized with folic acid (FA). To prepare the FA labelled NLC, the polymer PF127 was first esterified with FA and emulsified with an oil phase containing polyoxyethylene 40 stearate, capric/caprylic acid triglycerides, ethoxylated hydrogenated castor oil 40 and the PS zinc phthalocyanine. The resulting PS loaded FA-NLC had a hydrodynamic diameter of 180 nm and were stable in suspension for >90 days. Interestingly, the amount of singlet oxygen generated upon light activation for the PS loaded FA-NLC was substantially higher than the free PS, yet at a lower PS concentration. The PS was released from the NLC in a sustained manner with 4.13 ±â€¯0.58% and 27.7 ±â€¯3.16% after 30 min and 7 days, respectively. Finally, cytotoxicity assays showed that NLC in the concentrations of 09.1 µM of PS present non-toxic with >80 ±â€¯6.8% viable and after 90 s of the light-exposed the results show a statistically significant decrease in cell viability (57 ±â€¯4%). The results obtained allow us to conclude that the functionalized NLC incorporated with PS associated with the PDT technique have characteristics that make them potential candidates for the alternative treatment of breast cancer.

Hepatocellular carcinoma staging systems: Hong Kong liver cancer vs Barcelona clinic liver cancer in a Western population.

BACKGROUND: Despite being the world's most widely used system for staging and therapeutic guidance in hepatocellular carcinoma (HCC) treatment, the Barcelona clinic liver cancer (BCLC) system has limitations, especially regarding intermediate-grade (BCLC-B) tumors. The recently proposed Hong Kong liver cancer (HKLC) staging system appears useful but requires validation in Western populations. AIM: To evaluate the agreement between BCLC and HKLC staging on the management of HCC in a Western population, estimating the overall patient survival. METHODS: This was a retrospective study of HCC patients treated at a university hospital in southern Brazil between 2011 and 2016. Demographic, clinical, and laboratory data were collected. HCC staging was carried out according to the HKLC and BCLC systems to assess treatment agreement. Overall survival was estimated based on the treatment proposed in each system. RESULTS: A total of 519 HCC patients were assessed. Of these, 178 (34.3%) were HKLC-I; 95 (18.3%) HKLC-IIA; 47 (9.1%) HKLC-IIB; 29 (5.6%) HKLC-IIIA; 30 (5.8%) HKLC-IIIB; 75 (14.4%) HKLC-IV; and 65 (12.5%) HKLC-V. According to the BCLC, 25 (4.9%) were BCLC-0; 246 (47.4%) BCLC-A; 107 (20.6%) BCLC-B; 76 (14.6%) BCLC-C; and 65 (12.5%) BCLC-D. The general agreement between the two systems was 80.0% - BCLC-0 and HKLC-I (100%); BCLC-A and HKLC-I/HKLC-II (96.7%); BCLC-B and HKLC-III (46.7%); BCLC-C and HKLC-IV (98.7%); BCLC-D and HKLC-V (41.5%). When sub-classifying BCLC-A, HKLC-IIB, HKLC-IIIA and HKLC-IIIB stages according to the up-to-7 in/out criterion, 13.4, 66.0, 100 and 36.7%, respectively, of the cases were classified as up-to-7 out. CONCLUSION: In a Western population, the general agreement between the two systems was 80.0%, although in BCLC-B cases the agreement was low, suggesting that some individuals could be candidates for the curative treatment recommended by the HKLC. The authors suggest that the BCLC system should be routinely employed, although for BCLC-B cases it should be associated with the HKLC system.

Photodynamic and peptide-based strategy to inhibit Gram-positive bacterial biofilm formation.

The self-produced extracellular polymeric matrix of biofilms renders them difficult to eliminate once they are established. This makes the inhibition of biofilm formation key to successful treatment of biofilm infection. Antimicrobial photodynamic therapy (aPDT) and antimicrobial peptides offer a new approach as antibiofilm strategies. In this study sub-lethal doses of aPDT (with chlorin-e6 (Ce6-PDT) or methylene blue (MB-PDT)) and the peptides AU (aurein 1.2 monomer) or (AU)2K (aurein 1.2 C-terminal dimer) were combined to evaluate their ability to prevent biofilm development by Enterococcus faecalis. Biofilm formation was assessed by resazurin reduction, confocal microscopy, and infrared spectroscopy. All treatments successfully prevented biofilm development. The (AU)2K dimer had a stronger effect, both alone and combined with aPDT, while the monomer AU had significant activity when combined with Ce6-PDT. Additionally, it is shown that the peptides bind to the lipoteichoic acid of the E. faecalis cell wall, pointing to a possible key mechanism of biofilm inhibition.

Carboxyethyl aminobutyric acid (CEGABA) lacks cytotoxicity and genotoxicity and stimulates cell proliferation and migration in vitro.

Cosmeceuticals are cosmetics formulated using compounds with medical-like benefits. Though the antiaging effect of carboxyethyl aminobutyric acid (CEGABA) has been discussed, its action mechanism in cosmeceuticals remains unclear. This study assessed the in vitro efficacy and safety of CEGABA. NHI-3T3 mouse fibroblast cell line was treated with two CEGABA concentrations (50 and 500 µmol/L) for 24 h, 48 h, and 72 h. Cytotoxicity and genotoxicity were evaluated by colorimetry (MTT) and the alkaline version of the comet assay, respectively. Flow cytometry and the scratch-wound assay were used to assess cell-cycle phase distributions and cell migration rates. Compared with the untreated control, CEGABA increased cell growth 1.6 times after 72 h, independent of dose. The compound also decreased cell replication time by 4 h. These findings seem to be related with the approximately 1.5-times increase in phase S cells numbers. Importantly, in vitro wound healing improved roughly 20% after treatment with CEGABA for 24 h and persisted after 48 h, indicating culture recovery. The time-dependent proliferation and migration of fibroblasts induced by CEGABA besides the fact that the compound is neither genotoxic nor cytotoxic makes it an ideal candidate in the development of cosmeceuticals in antiaging therapy.

BCLC-B Subclassification and the Hong Kong Liver Cancer System in Intermediate Hepatocellular Carcinoma: Identifying Candidates for Curative Therapy.

INTRODUCTION: The intermediate stage of the Barcelona Clinic Liver Cancer (BCLC) classification includes a heterogenous population of patients with hepatocellular carcinoma (HCC), and palliative treatment with transarterial chemoembolization is recommended for all of them. In this regard, 2 other classifications could be useful, the subclassification BCLC-B (SUB) and the classification Hong Kong Liver Cancer (HKLC). OBJECTIVE: To determine the indication of curative or palliative treatment between SUB and HKLC in BCLC-B patients. PATIENTS AND METHODS: A retrospective study in HCC patients seen between 2011 and 2016 in southern Brazil. Demographic, clinical, and laboratory data were collected. HCC staging was performed with BCLC, SUB, and HKLC. RESULTS: A total of 570 patients with HCC were assessed, of whom 95 were classified as BCLC-B: 25 (26.0%) B1, 48 (50.5%) B2, 9 (9.5%) B3, and 13 (13.7%) B4. Overall median survival was 21.1 (95% confidence interval, 14.2-28.0) months. Median survival was higher for BCLC-B1 patients than in subgroups B3 (P=0.046) and B4 (P=0.001), and this was also seen for B2 versus B4 (P=0.044). Regarding the HKLC classification, a significantly higher median survival was observed for HKLC-I and HKLC-IIB in relation to the categories HKLC-IIIA (P<0.001 and 0.004, respectively) and HKLC-IIIB (P<0.001 and 0.006, respectively). When HKLC was applied, the following were identified as candidates for curative treatment: BCLC-B1, 24 (96.0%); BCLC-B2, 26 (54.2%); BCLC-B3, 0 (0%); and BCLC-B4, 3 (23.1%). CONCLUSION: In intermediate HCC, SUB was able to identify a subset of patients with a higher overall survival. According to HKLC, 55.8% of BCLC-B patients could receive curative treatment.

Effective treatment and decolonization of a dog infected with carbapenemase (VIM-2)-producing Pseudomonas aeruginosa using probiotic and photodynamic therapies.

BACKGROUND: Carbapenem-resistant bacterial infections are a critical problem in veterinary medicine with limited treatment options. OBJECTIVE: To describe effective probiotic and photodynamic therapy of a dog with gut colonization and ear infection caused by a hospital-associated lineage of carbapenemase (VIM-2)-producing Pseudomonas aeruginosa. ANIMALS: A 5-year-old Lhasa apso dog presented with otitis externa. METHODS AND MATERIALS: Unilateral otitis externa caused by carbapenem-resistant P. aeruginosa was treated with antimicrobial photodynamic therapy (aPDT) using methylene blue as photosensitizer [wavelength 660 nm, fluence 140 J/cm2 , 8 J and 80 s per point (six equidistant points), 100 mW, spot size 0.028 cm2 and fluence rate 3.5 W/cm2 ]. The isolated bacterial strain also was tested for susceptibility to in vitro aPDT where the survival fraction was quantified by colony forming unit counts after exposure to increasing light doses. For decolonization, probiotic supplements were orally administered (once daily) for 14 days. Effectiveness of probiotics and photodynamic therapy was evaluated by clinical and microbiological culture assays. RESULTS: Complete resolution of clinical signs was achieved by Day 7 after aPDT. Samples collected immediately and after seven and 14 days following aPDT were negative for VIM-2-producing P. aeruginosa. Oral and rectal swabs collected on days 7, 14 and 21 after probiotic therapy, confirmed effective gastrointestinal decolonization. CONCLUSIONS AND CLINICAL IMPORTANCE: Combined use of aPDT and probiotics could be a promising therapeutic strategy for treatment of superficial infections produced by carbapenem-resistant bacteria, while avoiding recurrent infection due to intestinal bacterial carriage of these multidrug-resistant pathogens.

Sorafenib for Advanced Hepatocellular Carcinoma: A Real-Life Experience.

INTRODUCTION: Sorafenib (SOR) has proved to be effective in patients with advanced hepatocellular carcinoma (HCC), since overall survival was higher in phase III clinical trials; however, disease progression can occur. OBJECTIVES: The study aimed to describe real-life experience in advanced HCC treatment with SOR at a university hospital in Brazil and to estimate the number of patients with indication of second-line therapy. METHODS: This is a retrospective study that included cases of HCC with prescription of SOR based on real-life practice between 2011 and 2016. Demographic, clinical, and laboratory data were collected. RESULTS: From 572 patients with HCC, SOR was prescribed in 103 cases. From them, 62.1% were classified as Child-Pugh (CP)-A, 54.4% as Barcelona Clinic Liver Cancer (BCLC)-C, and 74 (71.8%) started treatment. Overall survival was 25.5 (95% CI 17.0-34.1) months and 1-year survival was greater in patients who received SOR than in non-treated (88.7 vs. 44.4%, p < 0.001). There was no difference in survival between BCLC-B and C (p = 0.405), as well as CP-A and B (p = 0.919). In 21.6% of the patients, a second-line therapy with regorafenib was indicated. CONCLUSION: In this real-life study, SOR significantly increased the survival rate by 1 year in patients with advanced HCC regardless of BCLC staging and CP score. Second-line therapy would be indicated in 21.6% of cases.

Molecular analyses of two bacterial sampling methods in ligature-induced periodontitis in rats.

The prevalence profile of periodontal pathogens in dental plaque can vary as a function of the detection method; however, the sampling technique may also play a role in determining dental plaque microbial profiles. We sought to determine the bacterial composition comparing two sampling methods, one well stablished and a new one proposed here. In this study, a ligature-induced periodontitis model was used in 30 rats. Twenty-seven days later, ligatures were removed and microbiological samples were obtained directly from the ligatures as well as from the periodontal pockets using absorbent paper points. Microbial analysis was performed using DNA probes to a panel of 40 periodontal species in the checkerboard assay. The bacterial composition patterns were similar for both sampling methods. However, detection levels for all species were markedly higher for ligatures compared with paper points. Ligature samples provided more bacterial counts than paper points, suggesting that the technique for induction of periodontitis could also be applied for sampling in rats. Our findings may be helpful in designing studies of induced periodontal disease-associated microbiota.

Antimicrobial Photodynamic therapy enhanced by the peptide aurein 1.2.

In the past few years, the World Health Organization has been warning that the post-antibiotic era is an increasingly real threat. The rising and disseminated resistance to antibiotics made mandatory the search for new drugs and/or alternative therapies that are able to eliminate resistant microorganisms and impair the development of new forms of resistance. In this context, antimicrobial photodynamic therapy (aPDT) and helical cationic antimicrobial peptides (AMP) are highlighted for the treatment of localized infections. This study aimed to combine the AMP aurein 1.2 to aPDT using Enterococcus faecalis as a model strain. Our results demonstrate that the combination of aPDT with aurein 1.2 proved to be a feasible alternative capable of completely eliminating E. faecalis employing low concentrations of both PS and AMP, in comparison with the individual therapies. Aurein 1.2 is capable of enhancing the aPDT activity whenever mediated by methylene blue or chlorin-e6, but not by curcumin, revealing a PS-dependent mechanism. The combined treatment was also effective against different strains; noteworthy, it completely eliminated a vancomycin-resistant strain of Enterococcus faecium. Our results suggest that this combined protocol must be exploited for clinical applications in localized infections as an alternative to antibiotics.

Susceptibility of Enterococcus faecalis and Propionibacterium acnes to antimicrobial photodynamic therapy.

Bacterial resistance to available antibiotics nowadays is a global threat leading researchers around the world to study new treatment modalities for infections. Antimicrobial photodynamic therapy (aPDT) has been considered an effective and promising therapeutic alternative in this scenario. Briefly, this therapy is based on the activation of a non-toxic photosensitizing agent, known as photosensitizer (PS), by light at a specific wavelength generating cytotoxic singlet oxygen and free radicals. Virtually all studies related to aPDT involve a huge screening to identify ideal PS concentration and light dose combinations, a laborious and time-consuming process that is hardly disclosed in the literature. Herein, we describe an antimicrobial Photodynamic Therapy (aPDT) study against Enterococcus faecalis and Propionibacterium acnes employing methylene blue, chlorin-e6 or curcumin as PS. Similarities and discrepancies between the two bacterial species were pointed out in an attempt to speed up and facilitate futures studies against those clinical relevant strains. Susceptibility tests were performed by the broth microdilution method. Our results demonstrate that aPDT mediated by the three above-mentioned PS was effective in eliminating both gram-positive bacteria, although P. acnes showed remarkably higher susceptibility to aPDT when compared to E. faecalis. PS uptake assays revealed that P. acnes is 80 times more efficient than E. faecalis in internalizing all three PS molecules. Our results evidence that the cell wall structure is not a limiting feature when predicting bacterial susceptibility to aPDT treatment.

Optimization of Antimicrobial Photodynamic Therapy in Biofilms by Inhibiting Efflux Pump.

BACKGROUND: One of the main mechanisms of microbial resistance is given by efflux pumps, which reduce the effectiveness of antimicrobials by decreasing their intracellular concentration. OBJECTIVE AND METHODS: Considering that efflux pump inhibitors are promising adjuvant molecules for antibiotics in infections, in this study, using XTT test and colony forming unit (CFU) counting, we evaluated the association between the pump inhibitor verapamil (VP) and the antimicrobial photodynamic therapy (aPDT) mediated by methylene blue (MB) in biofilms of Escherichia coli and Staphylococcus aureus to optimize the bacterial reduction. RESULTS: By applying 44 J/cm2, 215 µg/mL of VP, and 200 µg/mL of MB, we obtained 80% of metabolism reduction and 3.4 log10 CFU/mL decrease for E. coli. Biofilm of S. aureus presented 80% of metabolism reduction and 3.65 log10 CFU/mL decrease when 22 J/cm2, 312 µg/mL of VP, and 200 µg/mL of MB was used. Applying 200 µg/mL of MB, the E. coli biofilm required a higher dose of light, while the S. aureus biofilm required a higher concentration of VP to obtain the same reduction. CONCLUSIONS: The VP optimized the efficiency of aPDT and showed no toxicity when used alone in both strains, proving that inhibiting efflux pumps in combination with aPDT has great potential for clinical application.

Photodynamic therapy combined to cisplatin potentiates cell death responses of cervical cancer cells.

BACKGROUND: Photodynamic therapy (PDT) has proven to be a promising alternative to current cancer treatments, especially if combined with conventional approaches. The technique is based on the administration of a non-toxic photosensitizing agent to the patient with subsequent localized exposure to a light source of a specific wavelength, resulting in a cytotoxic response to oxidative damage. The present study intended to evaluate in vitro the type of induced death and the genotoxic and mutagenic effects of PDT alone and associated with cisplatin. METHODS: We used the cell lines SiHa (ATCC® HTB35™), C-33 A (ATCC® HTB31™) and HaCaT cells, all available at Dr. Christiane Soares' Lab. Photosensitizers were Photogem (PGPDT) and methylene blue (MBPDT), alone or combined with cisplatin. Cell death was accessed through Hoechst and Propidium iodide staining and caspase-3 activity. Genotoxicity and mutagenicity were accessed via flow cytometry with anti-gama-H2AX and micronuclei assay, respectively. Data were analyzed by one-way ANOVA with Tukey's posthoc test. RESULTS: Both MBPDT and PGPDT induced caspase-independent death, but MBPDT induced the morphology of typical necrosis, while PGPDT induced morphological alterations most similar to apoptosis. Cisplatin predominantly induced apoptosis, and the combined therapy induced variable rates of apoptosis- or necrosis-like phenotypes according to the cell line, but the percentage of dead cells was always higher than with monotherapies. MBPDT, either as monotherapy or in combination with cisplatin, was the unique therapy to induce significant damage to DNA (double strand breaks) in the three cell lines evaluated. However, there was no mutagenic potential observed for the damage induced by MBPDT, since the few cells that survived the treatment have lost their clonogenic capacity. CONCLUSIONS: Our results elicit the potential of combined therapy in diminishing the toxicity of antineoplastic drugs. Ultimately, photodynamic therapy mediated by either methylene blue or Photogem as monotherapy or in combination with cisplatin has low mutagenic potential, which supports its safe use in clinical practice for the treatment of cervical cancer.

Polymeric Nanoparticle-Based Photodynamic Therapy for Chronic Periodontitis in Vivo.

Antimicrobial photodynamic therapy (aPDT) is increasingly being explored for treatment of periodontitis. Here, we investigated the effect of aPDT on human dental plaque bacteria in suspensions and biofilms in vitro using methylene blue (MB)-loaded poly(lactic-co-glycolic) (PLGA) nanoparticles (MB-NP) and red light at 660 nm. The effect of MB-NP-based aPDT was also evaluated in a clinical pilot study with 10 adult human subjects with chronic periodontitis. Dental plaque samples from human subjects were exposed to aPDT-in planktonic and biofilm phases-with MB or MB-NP (25 µg/mL) at 20 J/cm² in vitro. Patients were treated either with ultrasonic scaling and scaling and root planing (US + SRP) or ultrasonic scaling + SRP + aPDT with MB-NP (25 µg/mL and 20 J/cm²) in a split-mouth design. In biofilms, MB-NP eliminated approximately 25% more bacteria than free MB. The clinical study demonstrated the safety of aPDT. Both groups showed similar improvements of clinical parameters one month following treatments. However, at three months ultrasonic SRP + aPDT showed a greater effect (28.82%) on gingival bleeding index (GBI) compared to ultrasonic SRP. The utilization of PLGA nanoparticles encapsulated with MB may be a promising adjunct in antimicrobial periodontal treatment.

Synergistic antimicrobial effect of photodynamic therapy and ciprofloxacin.

The occurrence of a variety of pathogens resistant to current antibiotics remains the major problem in medical care, especially when bacterial infections are established as biofilms. In this study, we propose the use of photodynamic therapy (PDT) as a monotherapy and associated with antibiotic as an alternative treatment. The aim of this study was to analyze the effects of PDT mediated by methylene blue (MB) on Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) in both biofilm and planktonic phases. Several concentrations of MB and light doses were tested. The bactericidal effects of PDT as a monotherapy did not increase with the concentration of photosensitizer, but were light dose-dependent. In addition, bacteria in biofilms were less affected than cells in the planktonic phase. Although not concentration-dependent, the disruption effect of PDT on biofilms was clearly illustrated by scanning electron microscopy (SEM). We also carried out experiments that evaluated the synergistic effect of photodynamic therapy and the antibiotic ciprofloxacin. The best results were obtained after combination treatment of photodynamic therapy followed by ciprofloxacin on biofilms, which increased bacterial reduction on biofilms, resulting in a 5.4 log reduction for S. aureus biofilm and approximately 7 log for E. coli biofilm.

Nanotechnology-Based Drug Delivery Systems for Photodynamic Therapy of Cancer: A Review.

Photodynamic therapy (PDT) is a promising alternative approach for improved cancer treatment. In PDT, a photosensitizer (PS) is administered that can be activated by light of a specific wavelength, which causes selective damage to the tumor and its surrounding vasculature. The success of PDT is limited by the difficulty in administering photosensitizers (PSs) with low water solubility, which compromises the clinical use of several molecules. Incorporation of PSs in nanostructured drug delivery systems, such as polymeric nanoparticles (PNPs), solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs), gold nanoparticles (AuNPs), hydrogels, liposomes, liquid crystals, dendrimers, and cyclodextrin is a potential strategy to overcome this difficulty. Additionally, nanotechnology-based drug delivery systems may improve the transcytosis of a PS across epithelial and endothelial barriers and afford the simultaneous co-delivery of two or more drugs. Based on this, the application of nanotechnology in medicine may offer numerous exciting possibilities in cancer treatment and improve the efficacy of available therapeutics. Therefore, the aim of this paper is to review nanotechnology-based drug delivery systems for photodynamic therapy of cancer.