Photodynamic treatment as a novel approach in the therapy of arthritic joints

Synthesis, characterization of dialkylated erythrosin B derivatives and their utility as a propitious anti-microbial agent

The development of small molecule based drugs as an antimicrobial agent is an important area of research nowadays. In the present work, two new molecular entities based on dialkylated erythrosin B has been synthesized via Arbuzov type of rearrangement using dialkyl sulphite as a reagent in the presence of Et3N. Ethyl and methyl based dialkylated derivatives of erythrosin B were characterized using 1H NMR, 13C NMR and HRMS data. Keeping in mind the biological safety of erythrosin B, synthesized derivatives were checked for their antimicrobial activity against the microbial strains Escherichia coli (E.coli). The two were found to be effective against the E. coli with the antimicrobial activity similar to that of Ampicillin. Further, the trend of antimicrobial activity has been supported by DFT data analysis and it was observed that compound, B with low HOMO (–5.93 eV) and LUMO (–3.11 eV) energies is a better antimicrobial agent than compound A.

Ruthenium-based assemblies incorporating tetrapyridylporphyrin panels: a photosensitizer delivery strategy for the treatment of rheumatoid arthritis by photodynamic therapy

Ruthenium-based assemblies containing tetrapyridylporphyrin derivatives in their structures have been evaluated as photosensitizers to treat rheumatoid arthritis by photodynamic therapy.

Targeted photodynamic therapy selectively kills activated fibroblasts in experimental arthritis

Objective

In RA, synovial fibroblasts become activated. These cells express fibroblast activation protein (FAP) and contribute to the pathogenesis by producing cytokines, chemokines and proteases. Selective depletion in inflamed joints could therefore constitute a viable treatment option. To this end, we developed and tested a new therapeutic strategy based on the selective destruction of FAP-positive cells by targeted photodynamic therapy (tPDT) using the anti-FAP antibody 28H1 coupled to the photosensitizer IRDye700DX.

Methods

After conjugation of IRDye700DX to 28H1, the immunoreactive binding and specificity of the conjugate were determined. Subsequently, tPDT efficiency was established in vitro using a 3T3 cell line stably transfected with FAP. The biodistribution of [¹¹¹In]In-DTPA-28H1 with and without IRDye700DX was assessed in healthy C57BL/6N mice and in C57BL/6N mice with antigen-induced arthritis. The potential of FAP-tPDT to induce targeted damage was determined ex vivo by treating knee joints from C57BL/6N mice with antigen-induced arthritis 24 h after injection of the conjugate. Finally, the effect of FAP-tPDT on arthritis development was determined in mice with collagen-induced arthritis.

Results

28H1-700DX was able to efficiently induce FAP-specific cell death in vitro. Accumulation of the anti-FAP antibody in arthritic knee joints was not affected by conjugation with the photosensitizer. Arthritis development was moderately delayed in mice with collagen-induced arthritis after FAP-tPDT.

Conclusion

Here we demonstrate the feasibility of tPDT to selectively target and kill FAP-positive fibroblasts in vitro and modulate arthritis in vivo using a mouse model of RA. This approach may have therapeutic potential in (refractory) arthritis.

Energy Conversion-Based Nanotherapy for Rheumatoid Arthritis Treatment

Rheumatoid arthritis (RA) is characterized by synovial hyperplasia and cartilage/bone destruction, which results in a high disability rate on human health and a huge burden on social economy. At present, traditional therapies based on drug therapy still cannot cure RA, in accompany with the potential serious side effects. Based on the development of nanobiotechnology and nanomedicine, energy conversion-based nanotherapy has demonstrated distinctive potential and performance in RA treatment. This strategy employs specific nanoparticles with intrinsic physiochemical properties to target lesions with the following activation by diverse external stimuli, such as light, ultrasound, microwave, and radiation. These nanoagents subsequently produce therapeutic effects or release therapeutic factors to promote necrotic apoptosis of RA inflammatory cells, reduce the concentration of related inflammatory factors, relieve the symptoms of RA, which are expected to ultimately improve the life quality of RA patients. This review highlights and discusses the versatile biomedical applications of energy conversion-based nanotherapy in efficient RA treatment, in together with the deep clarification of the facing challenges and further prospects on the final clinical translations of these energy conversion-based nanotherapies against RA.

Photobiomodulation with 630-nm LED radiation inhibits the proliferation of human synoviocyte MH7A cells possibly via TRPV4/PI3K/AKT/mTOR signaling pathway

Phototherapy has been used to treat postoperative pain and inflammatory response in rheumatoid arthritis. Confidence in this approach, however, is impaired by lack of understanding of the light-triggered cellular and molecular mechanisms. The purpose of this study was to characterize the response of human synoviocyte MH7A cells to visible LED red light in an attempt to elucidate the associated action mechanism. Human synoviocyte MH7A cells were treated with 630-nm LED light after stimulation of tumor necrosis factor-α (TNF-α). The effects of light radiation on cell proliferation and migration were detected by MTT assay and scratch test. The expressions of inflammatory cytokines were measured using RT-qPCR. This was followed by detection of the levels of extracellular proteins IL-6 and IL-8 after differential radiation. Furthermore, the expression levels and activation of proteins on PI3K/AKT/mTOR signaling pathway were examined with Western blot. In terms of the proliferation and migration, repeated radiation with LED red light (630 nm, 26 and 39 J/cm²) exerted an inhibitory effect on synoviocyte MH7A cells. Expression of inflammatory factors (IL-6, IL-1β, IL-8, and MMP-3) was reduced; meanwhile, the expression of anti-inflammatory factor IL-10 was promoted. At the protein level, treatment with 39 J/cm² of LED red light could decrease the level of extracellular protein (IL-6 and IL-8) and affect the expression and phosphorylation of proteins on TRPV4/PI3K/AKT/mTOR signaling pathway induced by TNF-α. These results demonstrated that LED red light (630 nm) inhibits proliferation and migration of MH7A cells. The growth-inhibiting effects of LED red light on human synoviocyte MH7A cells appear to be associated with regulation of the TRPV4/PI3K/AKT/mTOR signaling pathway.

Correlation of synovial caspase-3 concentration and the photodynamic effectiveness in osteoarthritis treatment

BACKGROUND

The present study focuses on investigation of Intra-articular PDT mechanisms for OA treatment. Also, a search for determination of the most effective dose of chlorin e6 (Ce6) for anti-inflammatory PDT of OA was carried out.

METHODS

The study was carried out on laboratory animals (11 Chinchilla rabbits, 1 year, 2.5 kg) with a gonarthritis model of post-traumatic OA. According to the instructions for using Photoditazin (Ce6 based PS) for PDT of human oncological and non-oncological diseases, the recommended dose is 0.7-1.2 mg/kg. For studies on rabbits, taking into account the conversion coefficient (3.2), the PS doses of 2.4, 3.2 and 6.4 mg/kg were selected. Fluorescence spectra were measured intra-articular before and after PDT using spectrometer with fiber-optic probe. The intrajoint PDT was carried out using a laser (662 ± 10 nm) and a fiber-optic catheter with a cylindrical diffuser inside a sapphire needle for a uniform distribution of the laser radiation. The immunohistochemical study was carried out by staining the samples with caspase-3.

RESULTS

Histological and immunohistochemical analysis showed that the best PS dose for intravenous administration for PDT of rabbit gonarthritis is 3.2 mg/kg. The PS concentration directly in the synovial tissue was 0.5 mg/kg, and this was enough to achieve the most positive results to reduce the caspase-3 level.

CONCLUSION

The caspase-3 level correlates well with other signs of inflammation in the synovial membrane (edema, etc.). Therefore, to assess the PDT effectiveness in the treatment of gonarthritis accompanied by synovitis, it is sufficient to analyze only for caspase-3. The efficacy of PDT with Ce6 showed that 3.2 mg/kg PS dose (1 mg/kg for a human) is the most effective.

Nanomedicine - advantages for their use in rheumatoid arthritis theranostics

Rheumatoid arthritis (RA) is an autoimmune disease accompanies with synovial inflammation and progressive bone destruction. Currently, anti-rheumatic drugs need high dose and frequent use for a long-term, which lead to serious side effect and low patient compliance. To overcome above problems and improve clinical efficacy, nano-technology with targeting ability, sustained release and so forth, has been proposed on RA treatment and already achieved success in RA animal models. In this review, authors summarize and illustrate representative nanomedicine targeting to RA states, which is achieved either through passive or active targeting with high affinity to the receptors that are over-expressed in macrophages or angiogenesis. In particular, authors highlight the new strategies to promote the efficacy of nanoscale treatments through phototherapy and the addition of contrast elements for theranostic application. The described advances may pave the way to better understanding and designing the novel nanomedicine and multifunctional nano-system on efficient RA treatment.

Photosensitizers Used in the Photodynamic Therapy of Rheumatoid Arthritis

Photodynamic Therapy (PDT) has become one of the most promising treatment against autoimmune diseases, such as rheumatoid arthritis (RA), as well as in the treatment of different types of cancer, since it is a non-invasive method and easy to carry out. The three main ingredients of PDT are light irradiation, oxygen, and a photosensitizer (PS). Light irradiation depends on the type of molecule or compound to be used as a PS. The concentration of O₂ fluctuates according to the medium where the target tissue is located and over time, although it is known that it is possible to provide oxygenated species to the treated area through the PS itself. Finally, each PS has its own characteristics, the efficacy of which depends on multiple factors, such as solubility, administration technique, retention time, stability, excitation wavelength, biocompatibility, and clearance, among others. Therefore, it is essential to have a thorough knowledge of the disease to select the best PS for a specific target, such as RA. In this review we will present the PSs used in the last three decades to treat RA under PDT protocol, as well as insights on the relevant strategies.

Efficacy of Indocyanine Green-Mediated Sonodynamic Therapy on Rheumatoid Arthritis Fibroblast-like Synoviocytes

Sonodynamic therapy (SDT) has become a new therapeutic method because of its activation of certain sensitizers by ultrasound. Some studies have reported that indocyanine green (ICG) has the characteristics of a sonosensitizer and favorable fluorescence imaging in synovitis of early inflammatory arthritis. In this study, we aimed to investigate the cytotoxic effect of ICG-mediated SDT on MH7A cells in vitro and the potential mechanisms involved. ICG was found to be taken up mainly in cytoplasm, with maximal uptake in 4 h. Cell viability in ICG-mediated SDT (SDT-0.5 and SDT-1.0) groups decreased significantly to 73.09 ± 1.97% and 54.24 ± 4.66%, respectively; cell apoptosis increased significantly to 26.43 ± 0.91% and 45.93 ± 6.17%, respectively. Moreover, marked loss in mitochondrial membrane potential and greatly increased generation of reactive oxygen species were observed in ICG-mediated SDT groups. Interestingly, the loss in cell viability could be effectively rescued with pretreatment with the reactive oxygen species scavenger N-acetylcysteine. These results indicate that ICG-mediated SDT is cytotoxic to fibroblast-like synoviocytes and is a potential modality for targeted therapy of synovitis in rheumatoid arthritis.

Gonarthritis photodynamic therapy with chlorin e6 derivatives

BACKGROUND

The new methods of osteoarthritis treatment are in constant demand due to the complexity of the early diagnosis and therapy. Specific features of Сhlorin e6 derivative (Ce6) accumulation in knee joint tissues and the efficiency of photodynamic therapy (PDT) of gonarthritis were studied.

METHODS

The experimental research was conducted on the model of posttraumatic gonarthritis on rabbits. The analysis of dynamics of change of Ce6 concentration in tissues of a knee joint was carried out by the method of fluorescent diagnostics. The intra-joint PDT was carried out using 662nm laser with energy density of 120-150J/cm(2) and a sapphire diffuser. An analysis of slices was conducted to confirm the anti-inflammatory effect through apoptosis.

RESULTS

The method of fluorescent spectroscopy revealed that the highest amount of Ce6 was accumulated in the synovial membrane of a damaged knee joint 2.5h after its intravenous introduction. On 14th day after gonarthritis modeling but before PDT the synovial membrane showed signs of synovitis. On 21st day after PDT the synovial membrane possessed noticeable villous structure, and no cells of inflammatory nature were observed.

CONCLUSION

Fluorescent diagnostics in knee joint tissues can be used in clinical practice of gonarthritis before, during and after PDT for monitoring the Ce6 accumulation and for treatment control. Optimal radiation energy density was determined to be 150J/cm(2). In the studied time intervals (5-25min) no dependency of PDT effect on irradiation time at the same energy density was observed. The analysis of results of clinical and morphological research shows that PDT is a low-invasive method of gonarthritis treatment with a high degree of efficiency and selectivity.

Photodynamic therapy relieves colitis and prevents colitis-associated carcinogenesis in mice

BACKGROUND

Inflammatory bowel diseases are incurable illnesses of the gastrointestinal tract, which substantially enhance the risk of developing colorectal carcinogenesis. Conventional photodynamic therapy is a clinically approved therapeutic modality used in the treatment of neoplastic diseases. Recent preclinical and clinical studies have shown that photodynamic therapy with low doses of photosensitizer and/or light improves inflammatory conditions, including colitis. This study aims therefore at investigating the therapeutic potential of low-dose photodynamic therapy (LDPDT) with a liposomal formulation of meta-tetra(hydroxyphenyl)chlorin (namely Foslip) in the prevention of colitis-associated cancer in mice.

METHODS

LDPDT efficacy was evaluated by endoscopic, macroscopic, and histological analysis. Myeloperoxidase levels were quantified by enzyme linked immunosorbent assay and cytokines expression by quantitative RT-PCR analysis. The integrity of the intestinal barrier was evaluated by immunostaining, and bacterial composition of the fecal microbiota was determined by 454 pyrosequencing of V3-V4 region of bacterial 16S rRNA genes.

RESULTS

LDPDT reduced intestinal tumor growth by decreasing the expression of a wide range of inflammatory mediators and by lowering neutrophil influx. LDPDT treatment prevents onset of a dysbiotic microbiota in the colitis-associated cancer model.

CONCLUSIONS

LDPDT with Foslip could be considered as a novel treatment modality to prevent colorectal carcinogenesis in patients with inflammatory bowel disease.

Induction of protoporphyrin IX in patient-derived synoviocytes, cartilage explants and chondrons after application of 5-aminolevulinic acid or its methyl ester

OBJECTIVE

To compare the accumulation of protoporphyrin IX between synoviocytes of patients with rheumatoid arthritis (RA) or osteoarthritis (OA) and cartilage explants (CE) as well as chondrons of patients with OA after the application of 5-aminolevulinic acid (ALA) or its methyl ester (ALA-Me).

MATERIALS AND METHODS

Samples of synovial and cartilage tissues were obtained from joint replacement surgeries. The accumulation of PpIX was determined by measuring fluorescence spectra from 2 × 10(5) synoviocytes or chondrons suspended in a glass tube or directly from CE surface after 2, 4, 8 and 24h of incubation with ALA or ALA-Me.

RESULTS

No differences were found between the average fluorescence intensity values of PpIX in synoviocytes of patients with RA and OA. These values were non-significantly higher after incubation with ALA in comparison with ALA-Me at almost all time points. The average fluorescence intensity of PpIX in CE and chondrons was about ten times lower than in synoviocytes. The presence of preparation of hyaluronic acid (HA) significantly enhanced PpIX induction in chondrons versus treatment only with ALA.

CONCLUSIONS

A potential for the selective synovial sensitization with endogenous PpIX in comparison with cartilage tissue has been demonstrated in vitro after application of ALA or ALA-Me.

Dose response effect of Paracoccidioides brasiliensis in an experimental model of arthritis

Paracoccidioidomycosis (PCM) is caused by the dimorphic fungus Paracoccidioides brasiliensis (Pb) and corresponds to prevalent systemic mycosis in Latin America. The aim of the present work was to evaluate the dose response effect of the fungal yeast phase for the standardization of an experimental model of septic arthritis. The experiments were performed with groups of 14 rats that received doses of 10³, 10⁴ or 10⁵P. brasiliensis (Pb18) cells. The fungi were injected in 50 µL of phosphate-buffered saline (PBS) directly into the knee joints of the animals. The following parameters were analyzed in this work: the formation of swelling in knees infused with yeast cells and the radiological and anatomopathological alterations, besides antibody titer by ELISA. After 15 days of infection, signs of inflammation were evident. At 45 days, some features of damage and necrosis were observed in the articular cartilage. The systemic dissemination of the fungus was observed in 11% of the inoculated animals, and it was concluded that the experimental model is able to mimic articular PCM in humans and that the dose of 10⁵ yeast cells can be used as standard in this model.

Evaluation of the photodynamic activity of Xanthene Dyes on Artemia salina described by chemometric approaches

The development of drugs for photodynamic therapy (PDT) is an important area of research due to their growing use in medical applications. Therefore, it is important to develop new bioassay methods for PDT photosensitizers that are inexpensive, easy to handle and highly sensitive to environmental conditions. Xanthene dyes (fluorescein, rose bengal B, erythrosine B and eosin Y) with LED light sources were investigated using Artemia salina as a bioindicator of photodynamic activity. In this study, three factors were investigated: (i) photosensitizers concentration, (ii) the LED irradiation time and (iii) the waiting time between the addition of the photosensitizers and the beginning of the irradiation. To analyze the photo-killing of A. salina, it was employed a 23 full factorial design. The death of A. salina was related to dye structure and the interaction between the irradiation time and the photosensitizers concentration. About 60% of crustaceans death was obtained using rose bengal B, which presentes the highest quantum yield of singlet oxygen due to the number of iodide substituents in the xanthenes ring. The proposed bioassay using A. salina, xanthene dyes and LED irradiation was found suitable for quantitative PDT drug evaluation.

Current status of liposomal porphyrinoid photosensitizers

The complete eradication of various targets, such as infectious agents or cancer cells, while leaving healthy host cells untouched, is still a great challenge faced in the field of medicine. Photodynamic therapy (PDT) seems to be a promising approach for anticancer treatment, as well as to combat various dermatologic and ophthalmic diseases and microbial infections. The application of liposomes as delivery systems for porphyrinoids has helped overcome many drawbacks of conventional photosensitizers and facilitated the development of novel effective photosensitizers that can be encapsulated in liposomes. The development, preclinical studies and future directions for liposomal delivery of conventional and novel photosensitizers are reviewed.

Improved in vivo delivery of m-THPC via pegylated liposomes for use in photodynamic therapy

Pegylated liposomal nanocarriers have been developed with the aim of achieving improved uptake of the clinical PDT photosensitiser, m-THPC, into target tissues through increased circulation time and bioavailability. This study investigates the biodistribution and PDT efficacy of m-THPC in its standard formulation (Foscan®) compared to m-THPC incorporated in liposomes with different degrees of pegylation (FosPEG 2% and FosPEG 8%), following i.v. administration to normal and tumour bearing rats. The plasma pharmacokinetics were described using a three compartmental analysis and gave elimination half lives of 90 h, 99 h and 138 h for Foscan®, FosPEG 2% and 8% respectively. The accumulation of m-THPC in tumour and normal tissues, including skin, showed that maximal tumour to skin ratios were observed at ≤ 24 h with FosPEG 2% and 8%, whilst skin photosensitivity studies showed Foscan® induces more damage compared to the liposomes at drug-light intervals of 96 and 168 h. PDT treatment at 24h post-administration (0.05 mg kg⁻¹) showed higher tumour necrosis using pegylated liposomal formulations in comparison to Foscan®, which is attributed to the higher tumour uptake and blood plasma concentrations. Clinically, this improved selectivity has the potential to reduce not only normal tissue damage, but the drug dose required and cutaneous photosensitivity.

Temoporfin (Foscan®, 5,10,15,20-tetra(m-hydroxyphenyl)chlorin)--a second-generation photosensitizer

This review traces the development and study of the second-generation photosensitizer 5,10,15,20-tetra(m-hydroxyphenyl)chlorin through to its acceptance and clinical use in modern photodynamic (cancer) therapy. The literature has been covered up to early 2011.

DAMPs and PDT-mediated photo-oxidative stress: exploring the unknown

Damage-associated molecular patterns (DAMPs) or cell death associated molecular patterns (CDAMPs) are a subset of endogenous intracellular molecules that are normally hidden within living cells but become either passively released by primary and secondary necrotic cells or actively exposed and secreted by the dying cells. Once released, DAMPs are sensed by the innate immune system and act as activators of antigen-presenting cells (APCs) to stimulate innate and adaptive immunity. Cancer cells dying in response to a subset of conventional anticancer modalities exhibit a particular composition of DAMPs at their cell surface, which has been recently shown to be vital for the stimulation of the host immune system and the control of residual disease. Photodynamic therapy (PDT) for cancer has long been shown to be capable of killing malignant cells and concomitantly stimulate the host immune system, properties that are likely linked to its ability of inducing exposure/release of certain DAMPs. PDT, by evoking oxidative stress at specific subcellular sites through the light activation of organelle-associated photosensitizers, may be unique in incorporating tumour cells destruction and antitumor immune response in one therapeutic paradigm. Here we review the current knowledge about mechanisms and signalling cascades leading to the exposure of DAMPs at the cell surface or promoting their release, the cell death mechanism associated to these processes and its immunological consequences. We also discuss how certain PDT paradigms may yield therapies that optimally stimulate the immune system and lead to the discovery of new DAMPs.

Thrombin-sensitive photodynamic agents: a novel strategy for selective synovectomy in rheumatoid arthritis

Protease-sensitive macromolecular prodrugs have attracted interest for bio-responsive drug delivery to sites with up-regulated proteolytic activities such as inflammatory or cancerous lesions. Here we report the development of a novel polymeric photosensitizer prodrug (T-PS) to target thrombin, a protease up-regulated in synovial tissues of rheumatoid arthritis (RA) patients, for minimally invasive photodynamic synovectomy. In T-PS, multiple photosensitizer units are tethered to a polymeric backbone via short, thrombin-cleavable peptide linkers. Photoactivity of the prodrug is efficiently impaired due to energy transfer between neighbouring photosensitizer units. T-PS activation by exogenous and endogenous thrombin induced an increase in fluorescence emission by a factor of 16 after in vitro digestion and a selective fluorescence enhancement in arthritic lesions in vivo, in a collagen-induced arthritis mouse model. In vitro studies on primary human synoviocytes showed a phototoxic effect only after enzymatic digestion of the prodrug and light irradiation, thus demonstrating the functionality of T-PS induced PDT. The developed photosensitizer prodrugs combine the passive targeting capacity of macromolecular drug delivery systems with site-selective photosensitizer release and activation. They illuminate lesions with pathologically enhanced proteolytic activity and induce cell death, subsequent to irradiation.

The role of photodynamic therapy (PDT) physics

Photodynamic therapy (PDT) is an emerging treatment modality that employs the photochemical interaction of three components: light, photosensitizer, and oxygen. Tremendous progress has been made in the last 2 decades in new technical development of all components as well as understanding of the biophysical mechanism of PDT. The authors will review the current state of art in PDT research, with an emphasis in PDT physics. They foresee a merge of current separate areas of research in light production and delivery, PDT dosimetry, multimodality imaging, new photosensitizer development, and PDT biology into interdisciplinary combination of two to three areas. Ultimately, they strongly believe that all these categories of research will be linked to develop an integrated model for real-time dosimetry and treatment planning based on biological response.