Exploring photobiomodulation in the management of bowel diseases: a concise critical review.

The complexity of the gastrointestinal system plays a crucial role in coordinating essential processes such as digestion, nutrient absorption, and waste elimination. inflammatory bowel diseases (IBD) pose significant treatment challenges due to their complex aetiology and varied symptoms. Conventional therapeutic approaches often involve pharmacological interventions, which may have side effects and limited efficacy. Photobiomodulation (PBM), also known as low-level light therapy, has emerged as a promising therapeutic or adjunctive alternative in the treatment of intestinal diseases. The search was conducted in the MEDLINE database via PubMed, SCOPUS, covering the period from 1990 to 2024. A total of 72 studies were selected, of which 9 focused on inflammatory bowel diseases IBD, including ulcerative colitis (UC) and Crohn's disease (CD). Among these studies, 1 was clinical protocol while eight experimental. The results showed that PBM has a significant positive effect in IBD studies in rats, with reduction of intestinal inflammation, improvement of mucosal integrity, and modulation of the immune response. However, no clinical studies were found necessary to obtain results and establish effective and safe treatment protocols. Nevertheless, PBM holds potential as a non-invasive and complementary therapeutic approach for managing IBD, offering new perspectives for the treatment of chronic intestinal diseases. Therefore, this brief review emphasizes the need to transition from preclinical research to clinical research on this topic and highlights the scarcity of clinical studies.

Classification of Multiple H&E Images via an Ensemble Computational Scheme.

In this work, a computational scheme is proposed to identify the main combinations of handcrafted descriptors and deep-learned features capable of classifying histological images stained with hematoxylin and eosin. The handcrafted descriptors were those representatives of multiscale and multidimensional fractal techniques (fractal dimension, lacunarity and percolation) applied to quantify the histological images with the corresponding representations via explainable artificial intelligence (xAI) approaches. The deep-learned features were obtained from different convolutional neural networks (DenseNet-121, EfficientNet-b2, Inception-V3, ResNet-50 and VGG-19). The descriptors were investigated through different associations. The most relevant combinations, defined through a ranking algorithm, were analyzed via a heterogeneous ensemble of classifiers with the support vector machine, naive Bayes, random forest and K-nearest neighbors algorithms. The proposed scheme was applied to histological samples representative of breast cancer, colorectal cancer, oral dysplasia and liver tissue. The best results were accuracy rates of 94.83% to 100%, with the identification of pattern ensembles for classifying multiple histological images. The computational scheme indicated solutions exploring a reduced number of features (a maximum of 25 descriptors) and with better performance values than those observed in the literature. The presented information in this study is useful to complement and improve the development of computer-aided diagnosis focused on histological images.

Rose bengal-encapsulated chitosan nanoparticles for the photodynamic treatment of Trichophyton species.

Rose bengal (RB) solutions coupled with a green laser have proven to be efficient in clearing resilient nail infections caused by Trichophyton rubrum in a human pilot study and in extensive in vitro experiments. Nonetheless, the RB solution can become diluted or dispersed over the tissue and prevented from penetrating the nail plate to reach the subungual area where fungal infection proliferates. Nanoparticles carrying RB can mitigate the problem of dilution and are reported to effectively penetrate through the nail. For this reason, we have synthesized RB-encapsulated chitosan nanoparticles with a peak distribution size of ~200 nm and high reactive oxygen species (ROS) production. The RB-encapsulated chitosan nanoparticles aPDT were shown to kill more than 99% of T. rubrum, T. mentagrophytes, and T. interdigitale spores, which are the common clinically relevant pathogens in onychomycosis. These nanoparticles are not cytotoxic against human fibroblasts, which promotes their safe application in clinical translation.

In vitro cell compatibility study of rose bengal-chitosan adhesives.

BACKGROUND AND OBJECTIVES: Photochemical tissue bonding (PTB) using rose bengal (RB) in conjunction with light is an alternative technique to repair tissue without suturing. It was recently demonstrated that laser-irradiated chitosan films, incorporating RB, bonded firmly to calf intestine in vitro. It is thus required to investigate the possible cytotoxic effects of the RB-chitosan adhesive on cells before testing its application to in vivo models. MATERIALS AND METHODS: Adhesive films, based on chitosan and containing ~0.1 wt% RB were fabricated. Their cytotoxicity was assessed by growing human and murine fibroblasts either in media in which adhesive strips had been incubated, or directly on the adhesive. The adhesive was either laser-irradiated or not. Cells were stained after 48 hours with Trypan blue and the number of live and dead cells was recorded for cell viability. RESULTS: Murine and human fibroblasts grew confluent on the adhesives with no apparent morphological changes or any exclusion zone. Cell numbers of murine fibroblasts were not significantly different when cultured in media that was extracted from irradiated (86 ± 7%) and non-irradiated adhesive (89 ± 4%). A similar result was obtained for the human fibroblasts. CONCLUSIONS: These findings support that the RB-chitosan films induced negligible toxicity and growth retardation in murine and human fibroblasts.

Laser Photobiomodulation of the Induratio Penis Plastica or La Peyronie's Syndrome.

Background: Since 1980, laser therapy has been proposed with success in the treatment of the Induratio Penis Plastica (IPP), also called La Peyronie's Syndrome, but still few physicians use it. Objective: We would like to investigate the clinical effects of using more laser sequentially in each session, in the treatment of chronic IPP. We used high levels of energy, watts rather than milliwatts, reducing the duration of each application, and the number of the cycles in total. Materials and methods: Laser wavelengths used for photobiomodulation (PBM) were 808, 1064, and 10,600 nm. Taking into account the clinical aspect of the lesion being treated, the specific dosage for each patient was determined. Penis echography established the exact localization and extension of the pathologic fibrous tissue as plaque, nodules, and ring. From 2012 to 2019, we treated 41 patients, 35-65 years old, who were selected using the same criteria: inflammatory signs present since ≥12 months, negative results with two other types of physical therapy, and exclusion of surgical cases. Results: Echographic test was repeated 1 month after the end of the treatment, for the evaluation of the results. Further parameters of results evaluation were presence/absence of pain, inflammation, recurvation, and functional limitation. The control was done comparing similar cases not treated with laser, selected with random criteria. Discussion and conclusions: Results were positive in a high percentage of patients, the majority after one cycle of treatment, and follow-up was positive after 2 years. The sequential use of more laser with wavelengths listed above gave better results than the wavelengths used up until the year 2000, in our previous experience. We need fewer cycles to obtain positive results, and follow-up improved significantly.

Stimulation and Repair of Peripheral Nerves Using Bioadhesive Graft-Antenna.

An original wireless stimulator for peripheral nerves based on a metal loop (diameter ≈1 mm) that is powered by a transcranial magnetic stimulator (TMS) and does not require circuitry components is reported. The loop can be integrated in a chitosan scaffold that functions as a graft when applied onto transected nerves (graft-antenna). The graft-antenna is bonded to rat sciatic nerves by a laser without sutures; it does not migrate after implantation and is able to trigger steady compound muscle action potentials for 12 weeks (CMAP ≈1.3 mV). Eight weeks postoperatively, axon regeneration is facilitated in transected nerves that are repaired with the graft-antenna and stimulated by the TMS for 1 h per week. The graft-antenna is an innovative and minimally-invasive device that functions concurrently as a wireless stimulator and adhesive scaffold for nerve repair.

Effects of laser therapy and Grimaldi's muscle shortening manoeuvre on motor control of subjects with incomplete spinal cord injuries.

BACKGROUND AND OBJECTIVES: From year 2003 we treated positively 251 patients with Traumatic Spinal Cord Injuries (TSCI), using Non-Surgical Laser Therapy (NSLT). In order to increase muscle strength, we have also started using a physical therapy practice called Grimaldi's Muscle Shortening Manoeuvre (GMSM)The goal of our study is to obtain objective data suggesting the real effectiveness of the association of these two treatments. STUDY DESIGN AND METHODS: In 2015, 10 patients with incomplete TSCI were enrolled. Further 10 subjects with similar features were included as control group. All patients have subtotal sensory loss and motor paralysis below the level of the lesion. Lasers used were 808, 10600, and 1064 nm, applied with a first cycle of four sessions per day for a total of 20 sessions. The patients participated in specific physical therapy training (GMSM) twice a day, for a total of eight sessions.Each cycle of laser and GMSM was replicated each month. RESULTS: Results were considered positive if sensitivity increased at least two dermatomes per cycle under the level of the lesion. Results in muscle activity (on/off) were regarded as positive if sEMG showed modifications in CNS-muscle. Objective assessment of force displayed encouraging results. After each cycle, patients showed improvements in motor function and voluntary command. Follow-up is positive after 3 months. CONCLUSION: Associating laser treatment and Grimaldi's Muscle Shortening Manoeuvre (MSM) seems to be effective on muscle strength and motor control in patients affected by subtotal SCI compared to a control group.

Features based on the percolation theory for quantification of non-Hodgkin lymphomas.

Non-Hodgkin lymphomas are a health problem that affects over 70,000 people per year in the United States alone. The early diagnosis and the identification of this lymphoma are essential for an effective treatment. The classification of non-Hodgkin lymphomas is a task that continues to rank as one of the main challenges faced by hematologists, pathologists, as well as in the producing of computer vision methods due to its inherent complexity. In this paper, we present a new method to quantify and classify tissue samples of non-Hodgkin lymphomas based on the percolation theory. The method consists of associating multiscale and multidimensional approaches in order to divide the image into smaller regions and then verifying color similarity between pixels. A cluster labeling algorithm was applied to each region of interest to obtain the values for the number of clusters, occurrence of percolation and coverage ratio of the largest cluster. The method was tested on different classifiers aiming to differentiate three different groups of non-Hodgkin lymphomas. The obtained results (AUC rates between 0.940 and 0.993) were compared to those provided by methods consolidated in the Literature, which indicates that the percolation theory is a suitable approach for identifying these three classes of non-Hodgkin lymphomas, those being: mantle cell lymphoma, follicular lymphoma and chronic lymphocytic leukemia.

Photobiomodulation improves cutaneous wound healing in an animal model of type II diabetes.

OBJECTIVE: We investigated the effects of photobiomodulation (PBM) on cutaneous wound healing in an animal model of type II diabetes, Psammomys obesus (Sand Rats). BACKGROUND DATA: 632-nm light has been established as the most effective wavelength for treatment of cutaneous wounds; however, the inconsistent efficacy of PBM may be due to inadequate treatment parameter selection. METHODS: Using 632-nm light, an initial series of experiments were done to establish optimal treatment parameters for this model. Following creation of bilateral full-thickness skin wounds, non-diabetic Sand Rats were treated with PBM of differing dosages. Wound healing was assessed according to wound closure and histological characteristics of healing. Optimal treatment parameters were then used to treat type II diabetic Sand Rats while a diabetic control group received no irradiation. In order to elucidate the mechanism behind an improvement in wound healing, expression of basic fibroblast growth factor (bFGF) was assessed. RESULTS: Significant improvement in wound healing histology and wound closure were found following treatment with 4 J/cm(2) (16 mW, 250-sec treatments for 4 consecutive days; p < 0.05). The 4 J/cm(2) dosage significantly improved histology and closure of wounds in the diabetic group in comparison to the non-irradiated diabetic group. Quantitative analysis of bFGF expression at 36 h post-injury revealed a threefold increase in the diabetic and non-diabetic Sand Rats after PBM. CONCLUSIONS: The results demonstrate that PBM at an energy density of 4 J/cm(2) is effective in improving the healing of cutaneous wounds in an animal model of type II diabetes, suggesting that PBM (632 nm, 4 J/cm(2)) would be effective in treating chronic cutaneous wounds in diabetic patients.

Fabrication and application of rose bengal-chitosan films in laser tissue repair.

Photochemical tissue bonding (PTB) is a sutureless technique for tissue repair, which is achieved by applying a solution of rose bengal (RB) between two tissue edges(1,2). These are then irradiated by a laser that is selectively absorbed by the RB. The resulting photochemical reactions supposedly crosslink the collagen fibers in the tissue with minimal heat production(3). In this report, RB has been incorporated in thin chitosan films to fabricate a novel tissue adhesive that is laser-activated. Adhesive films, based on chitosan and containing ~0.1 wt% RB, are fabricated and bonded to calf intestine and rat tibial nerves by a solid state laser (λ=532 nm, Fluence~110 J/cm(2), spot size~0.5 cm). A single-column tensiometer, interfaced with a personal computer, is used to test the bonding strength. The RB-chitosan adhesive bonds firmly to the intestine with a strength of 15 ± 6 kPa, (n=30). The adhesion strength drops to 2 ± 2 kPa (n=30) when the laser is not applied to the adhesive. The anastomosis of tibial nerves can be also completed without the use of sutures. A novel chitosan adhesive has been fabricated that bonds photochemically to tissue and does not require sutures.

A reasonable mechanism for visible light-induced skin rejuvenation.

In recent years, much research has been done in the field of non-ablative skin rejuvenation. This comes as a response to the continuous demand for a simple method of treating rhytides, UV exposure, and acne scars. Numerous researches involve visible light-pulsed systems (20-30 J/cm(2)). The mechanism of action is believed to be a selective heat-induced denaturalization of dermal collagen that leads to subsequent reactive synthesis (Bitter Jr., Dermatol. Surg., 26:836-843, 2000; Fitzpatrick et al., Arch. Dermatol., 132:395-402, 1996; Kauvar and Geronemus, Dermatol. Clin., 15:459-467, 1997; Negishi et al., Lasers Surg. Med., 30:298-305, 2002; Goldberg and Cutler, Lasers Surg. Med., 26:196-200, 2000; Hernandez-Perez and Ibeitt, Dermatol. Surg., 28:651-655, 2002). In this study, we suggest a different mechanism for photorejuvenation based on light-induced reactive oxygen species (ROS) formation. We irradiated collagen in vitro with a broadband of visible light (400-800 nm, 24-72 J/cm(2)) and used the spin trapping coupled with electron paramagnetic resonance spectroscopy to detect ROS. Irradiated collagen resulted in hydroxyl radicals formation. We propose, as a new concept, that visible light at the energy doses used for skin rejuvenation (20-30 J/cm(2)) produces high amounts of ROS, which destroy old collagen fibers, encouraging the formation of new ones. On the other hand, at inner depths of the skin, where the light intensity is much weaker, low amounts of ROS are formed, which are well known to stimulate fibroblast proliferation.