Comparison between local abdominal and transcutaneous tail vein photobiomodulation in experimental rat model of ulcerative colitis.

Ulcerative colitis (UC) is a chronic autoimmune disease that impacts the quality of life, but current pharmacological treatments are limited. Photobiomodulation (PBM) is a light-based treatment that can be applied either locally or systemically. Here, we compare the effects of local and vascular PBM (VPBM) in an experimental rat model of UC. Male Wistar rats were induced with UC by rectal instillation of acetic acid and treated with either local abdominal PBM or VPBM to the tail vein using a 660-nm LED. The findings indicated that local PBM but not VPBM reduced intestinal histological scores. Both local and VPBM increased mucus production, decreased mast cell degranulation, and modulated TNF-α and IL-1 ß levels in the intestines. Local PBM also affected the expression of the mRNAs for IL-6, TNF-α, and IFN-γ. In conclusion, we suggest that local PBM appears to be more promising than VPBM for treating UC. However, further research is needed to fully understand the mechanisms and to optimize the parameters of PBM for UC treatment.

Can Photons Pass through Primary Coatings Used to Treat Cutaneous Wounds?

OBJECTIVE: To determine the transmittance spectrum of primary dressings commonly used in the treatment of cutaneous wounds to verify if there is a real need to remove them during photobiomodulation. METHODS: Spectroscopic analysis was performed on 17 dressings using a spectrophotometer (USB 2000+; OceanOptics, Delray Beach, Florida). A piece of each dressing was inserted into a quartz cuvette; the reflection from the slide walls was corrected for using a 0.9% saline solution to completely fill the cuvette (baseline). The transmittance of each dressing was measured between 350 and 950 nm, and a transmittance table was created based on the main wavelengths used in photobiomodulation. RESULTS: Six dressings (Supriderme, Membracel, Cuticell Contact, UrgoTul, Tegaderm, and Opsite Flexigrid) have a transmittance greater than 50% in most of the spectral range and therefore may remain on wounds during irradiation. CONCLUSIONS: It may not always be necessary to remove a primary dressing when lasers or LED lights are used to treat wounds. It is the authors' hope that the results of this article will increase the effectiveness of both photobiomodulation and primary dressings and reduce patient discomfort as well as the cost of primary dressings via a reduction in unnecessary dressing changes.

Effects of photobiomodulation on interleukin-10 and nitrites in individuals with relapsing-remitting multiple sclerosis - Randomized clinical trial.

OBJECTIVE: Investigate the effects of photobiomodulation (PBM) on the expression of IL-10 and nitrites in individuals with Relapsing-Remitting multiple sclerosis (MS), as these biomarkers play a fundamental role in the physiopathology of the disease. The modulation of IL-10 and nitrites through treatment with PBM may be a novel treatment modality for MS. METHODS: A randomized, uncontrolled, clinical trial was conducted involving 14 individuals with a diagnosis of Relapsing-Remitting MS and a score of up to 6.0 on the Expanded Disability Status Scale (EDSS). THE PARTICIPANTS WERE RANDOMIZED TO TWO GROUPS: Group 1 -PBM in the sublingual region; Group 2 -PBM over the radial artery. Irradiation was administered with a wavelength of 808 nm and output power of 100 mW for 360 seconds twice a week, totaling 24 sessions. Peripheral blood was analyzed for the determination of serum levels of IL-10 and nitrites. RESULTS: After treatment with PBM, the expression of IL-10 increased in both the sublingual group (pre-treatment: 2.8 ± 1.4 pg/ml; post-treatment: 8.3 ± 2.4 pg/ml) and the radial artery group (pre-treatment: 2.7 pg/ml ± 1.4; post-treatment: 11.7 ± 3.8 pg/ml). In contrast, nitrite levels were not modulated in the sublingual group (pre-treatment: 65 ± 50 nmol/mg protein; post-treatment: 51 ± 42 nmol/mg protein) or the radial artery group (pre-treatment: 51 ± 16 nmol/mg protein; post-treatment: 42 ± 7 nmol/mg protein). CONCLUSION: Treatment with PBM positively modulated the expression of IL-10 but had no effect on nitrite levels. Further studies should be conducted with a larger sample and a control group, as PBM may be a promising complementary treatment for the management of MS. This trial is registered at ClinicalTrials.gov. Identifier: NCT03360487.

Checkpoint inhibitor blockade and epigenetic reprogrammability in CD8+ T-cell activation and exhaustion.

CD8+ T-cell exhaustion is a dysfunctional state that is regulated through the expression of inhibitory checkpoint receptor genes including the cytotoxic T-lymphocyte-associated antigen 4, programmed death 1, and DNA methylation of effector genes interferon-γ, perforin, and granzyme B. Different strategies have been used to reverse T-cell exhaustion, which is an adverse event of checkpoint inhibitor blockade. Here, we present the mechanisms by which DNA methyltransferase inhibitors and Simian virus 40 large T antigen through viral mimicry can promote the reversion of exhausted CD8+ T cells. We examine how these pharmacological strategies can work together to improve the clinical efficacy of immunotherapies.

Photobiomodulation is associated with a decrease in cell viability and migration in oral squamous cell carcinoma.

The treatment of squamous cell carcinoma (SCC) involves surgery, chemotherapy, and/or radiotherapy, which can cause mucositis (inflammation of the oral mucosa that causes considerable pain and can compromise the continuity of oncological treatment). Photobiomodulation (PBM) has been successfully used in the treatment of mucositis, but doubts arise regarding the use of laser for areas in which tumor cells may remain. In this study, the effect of PBM on the viability, mitochondrial activity, proliferation, apoptosis, and migration of cells derived from oral SCC was evaluated. SCC9 cells were irradiated with laser (660 and 780 nm, using 11 dosimetric parameters) and submitted to mitochondrial and caspase 3 activity tests after 1 and 3 days. Based on the results, cell viability (neutral red assay), proliferation (BrdU assay), and migration (scratch-wound assay) were evaluated using only the dosimetric parameters recommended for mucositis. Non-irradiated cells served as the control. The experiments were performed in triplicate. The 11 parameters diminished mitochondrial activity and induced tumor cell apoptosis. Using the parameters recommended for mucositis, irradiation with 780 nm (70 mW, 4 J/cm2) proved to be the safest and led to a reduction in cell viability, the induction of apoptosis, and a reduction in the migration capacity of the tumor cells.

When and how NK cell-induced programmed cell death benefits immunological protection against intracellular pathogen infection.

NK cells are innate lymphoid cells that exert a key role in immune surveillance through the recognition and elimination of transformed cells and viral, bacterial, and protozoan pathogen-infected cells without prior sensitization. Elucidating when and how NK cell-induced intracellular microbial cell death functions in the resolution of infection and host inflammation has been an important topic of investigation. NK cell activation requires the engagement of specific activating, co-stimulatory, and inhibitory receptors which control positively and negatively their differentiation, memory, and exhaustion. NK cells secrete diverse cytokines, including IFN-γ, TNF-α/ß, CD95/FasL, and TRAIL, as well as cytoplasmic cytotoxic granules containing perforin, granulysin, and granzymes A and B. Paradoxically, NK cells also kill other immune cells like macrophages, dendritic cells, and hyper-activated T cells, thus turning off self-immune reactions. Here we first provide an overview of NK cell biology, and then we describe and discuss the life-death signals that connect the microbial pathogen sensors to the inflammasomes and finally to cell death signaling pathways. We focus on caspase-mediated cell death by apoptosis and pro-inflammatory and non-caspase-mediated cell death by necroptosis, as well as inflammasome- and caspase-mediated pyroptosis.

Effects of Cetuximab and Erlotinib on the behaviour of cancer stem cells in head and neck squamous cell carcinoma.

The therapeutic responses of many solid tumours to chemo- and radio-therapies are far from fully effective but therapies targeting malignancy-related cellular changes show promise for further control. In head and neck squamous cell carcinoma, the epidermal growth factor receptor (EGFR) is commonly overexpressed and investigation of agents that block this receptor indicate a limited response when used alone but an ability to enhance the actions of other drugs. The hierarchical stem cell patterns present in tumours generate cellular heterogeneity and this is further complicated by cancer stem cells (CSC) shifting between epithelial (Epi-CSC) and mesenchymal (EMT-CSC) states. To clarify how such heterogeneity influences responses to EGFR blocking, we examined the effects of Cetuximab and Erlotinib on the cell sub-populations in HNSCC cell lines. These agents reduced cell proliferation for all subpopulations but induced little cell death. They did however induce large shifts of cells between the EMT-CSC, Epi-CSC and differentiating cell compartments. Loss of EMT-CSCs reduced cell motility and is expected to reduce invasion and metastasis. EGFR blocking also induced shifts of Epi-CSCs into the differentiating cell compartment which typically has greater sensitivity to chemo/radiation, an effect expected to enhance the overall response of tumour cell populations to adjunctive therapies.

Embryonic stem cells markers Oct4 and Nanog correlate with perineural invasion in human salivary gland mucoepidermoid carcinoma.

BACKGROUND: Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy and is successfully treated by surgery and radiation. However, some patients have recurrent tumours and in these cases, few treatments options are available. Cancer stem cells (CSC) have been observed and isolated from different solid tumours based on the expression of stem cell markers. These cells are associated with tumour initiation, progression as well as treatment resistance. In this study, the expression of stem cell markers CD44, Bmi1, Oct4 and Nanog was evaluated in non-neoplastic salivary tissue and in MEC. METHODS: Twenty-eight samples of MEC and their corresponding non-neoplastic salivary tissue were examined by immunohistochemistry and the stem cell markers expression was correlated with histological and clinical parameters. RESULTS: CD44 was expressed in the membrane of serous and mucous acini as well as in the ductal cells in normal gland tissue. Bmi1, Oct4 and Nanog were mainly expressed in ductal structures. In MEC, CD44 and Bmi1 showed strong expression in all types of neoplastic cells and both markers revealed intense expression in tumour invasive front. Oct4 and Nanog protein expression was associated with desmoplasia and perineural invasion. Only Oct4 positive tumours were associated with dissociative growth pattern and committed margins. CONCLUSION: The stem cell markers CD44, Bmi1, Oct4 and Nanog are frequently expressed in MEC in relation to normal salivary gland and Oct4 and Nanog expression may contribute to aggressiveness and worst prognosis in MEC patients.