Luis Mariñas-Pardo

SUMMARY: The current health crisis caused by multidrug resistant (MDR) pathogens is one of the health problems of most concern globally. Infections caused by these pathogens, such as Pseudomonas aeruginosa , lead to high rates of complications, particularly in compromised patients such as cystic fibrosis (CF) patients. The need to counteract and minimize the forecast future impact has led to the rescue of phage therapy. The use of bacteriophages has important advantages, including highly specific targeting, self-amplification at the infection site, minimal disruption of the microbiome, safety and biocompatibility. However, the capacity of bacteria to escape these entities results in a form of resistance that compromises the effectiveness of the therapy. This involves the search for potential alternatives, such as the phage tail-like bacteriocins (PTLBs), also named as tailocins. These high molecular weight particles resemble the tail structure of bacteriophages and are characterized by the absence of genetic material, avoiding the development of resistance, one of the major handicaps associated with phage therapy. In this study, we detected 34 different PTLBs in 75 P. aeruginosa genomes, with different serotypes and sequence types, 11 of which were characterized as novel F-type PTLBs subtypes (F13-F24). Furthermore, we report that four selected PTLBs (R1, F15, F19, R3-F24) can deal with bacterial infection, with the R1 and the F15 PTLBs being the most efficient in clearing infection in vitro , yielding a survival rate of more than 75% in the Galleria mellonella larvae in vivo model. This reaffirms the potential of PTLBs to control P. aeruginosa infections, which can cause chronic infections in some patients, such as people with CF, due to its strong impact as a MDR bacterium. GRAPHICAL HIGHLIGHTS: -The 75 Pseudomonas aeruginosa genomes from people with cystic fibrosis in the study collection included at least one Phage tail-like bacteriocins (PTLB) cluster. -From the 34 different PTLBs detected in the study collection, 7 were R-type, 10 were complex (R and F-type encoded) and 14 were F-type PTLBs. -11 new F-type PTLBs were described in the Pseudomonas aeruginosa collection under study. -An association between the O-antigen present on the surface of the Pseudomonas aeruginosa isolate and the encoded PTLB subtype was detected. -The R1 and F15 PTLBs subtypes display high antimicrobial activity both in vitro and in vivo ( Galleria mellonella ).

Asthma, a debilitating chronic inflammatory airway disorder, necessitates innovative therapeutic approaches. Equine spontaneous asthma (SEA) provides a unique, naturally occurring model, mirroring human asthma characteristics. SEA, linked to environmental factors, offers insights into inflammatory processes in equine medicine. This study explores the safety and efficacy of inhaled mesenchymal stem cell (MSC) supernatant as a treatment for SEA. Methods: Supernatants obtained from equine MSCs, primed with Toll-like Receptor ligands or immune-related factor, were developed as a new SEA treatment. First, we develop a safety protocol in mice. Second, horses diagnosed with SEA underwent bronchoalveolar lavage, and respiratory mechanics were treated with polarized and non-polarized MSC supernatants. Clinical and cellular responses were monitored. Results: Polarized equine MSC supernatant were obtained and used as treatment. Respiratory mechanics in mice showed no significant differences between control and treated groups. Safety trials in horses demonstrated good clinical responses and stability in cell counts post-treatment. Polarized MSC treatment showed diverse responses, with a notable decrease in neutrophils and clinical improvement after 10 days in some horses. Conclusions: Inhaled polarized-MSC supernatant presents a potential therapeutic avenue for SEA, although specific efficacy trials to support this hypothesis are needed. Moreover, the equine model provides translational insights, offering a bridge between rodent studies and human trials, emphasizing the potential of this approach in managing human asthma.

Acute myocardial infarction (AMI) is a pandemic in which conventional risk factors are inadequate to detect who is at risk early in the asymptomatic stage. Although gene variants in genes related to cholesterol, which may increase the risk of AMI, have been identified, no studies have systematically screened the genes involved in this pathway. In this study, we included 105 patients diagnosed with AMI with an elevation of the ST segment (STEMI) and treated with primary percutaneous coronary intervention (PPCI). Using next-generation sequencing, we examined the presence of rare variants in 40 genes proposed to be involved in lipid metabolism and we found that 60% of AMI patients had a rare variant in the genes involved in the cholesterol pathway. Our data show the importance of considering the wide scope of the cholesterol pathway in order to assess the genetic risk related to AMI.

Keratoconjunctivitis sicca (KCS) is characterized by ocular discomfort, conjunctival hyperaemia, and corneal scarring, causing reduced aqueous tear production that can be measured using the standard Schirmer tear test (STT). Canine adipose tissue-derived MSCs (cATMSCs) have been proposed as treatment due to their anti-inflammatory effect, by releasing cytokines and immunomodulatory soluble factors. Purpose: The aim of this study was to evaluate the effect of the systemic administration of cATMSCs on tear production in dogs with immune-mediated KCS, compared to classical Cyclosporine A (CsA) treatment. Methods: Twenty-eight client-owned dogs with spontaneous KCS were allocated in the experimental group (n = 14, treated with systemic cATMSCs or control group (n = 14, treated with CsA). SST values increased significantly at days 15 (p = 0.002), 45 (p = 0.042) and 180 (p = 0.005) with no observed side-effects in the experimental group. Eyes with an initial STT value of 11–14 mm/min maintained significant improvement at day 180, needing only artificial tears as treatment. Eyes with an initial STT value <11 mm/min needed cyclosporin treatment at day 45, so follow-up was stopped. Control animals treated with CsA did not improve their STT at day 180. Results and Conclusions: Systemic allogeneic cATMSCs application appeared to be a feasible and effective therapy with positive outcome in dogs with initial STT between 11–14 mm/min, with a significant improvement in tear production. The STT increment was maintained for at least 180 days, without needing additional medication, thus suggesting it could constitute an alternative therapy to classical immunosuppressive treatments.

Environmental Health Perspectives is an Open Access journal published by the National Institute of Environmental Health Sciences. Environmental Health Perspectives is an Open Access journal published by the National Institute of Environmental Health Sciences.

New sampling techniques to analyse lung diseases, such as exhaled breath condensate (EBC), are a breakthrough in research field since they are less invasive and less traumatic for the patients compared to lung biopsies. Nevertheless, there is an increasing need to optimize not only the sampling protocols but the storage and processing of specimens to get accurate results.

OA Text is an independent open-access scientific publisher showcases innovative research and ideas aimed at improving health by linking research and practice to the benefit of society.

Canine atopic dermatitis (AD) is a common skin disease with a 10–15 per cent prevalence. Current treatments vary in their efficacy and safety. The immunomodulatory properties of mesenchymal stem cells (MSCs) make them a promising alternative treatment. The aim of this study was to evaluate the therapeutic efficacy and safety of allogeneic canine adipose MSCs (cAd‐MSCs) in dogs with refractory AD. Twenty‐six dogs, suffering from AD for at least 12 months, not responding to conventional therapy, received an intravenous dose of 1.5×10 ⁶ cAd‐MSCs/kg bodyweight. Clinical signs, haematological and biochemistry profiles, and AD severity were assessed in a six‐month follow‐up using a validated scoring system (Canine Atopic Dermatitis Extent and Severity Index, version 4 (CADESI‐04)). The degree of pruritus was quantified using a validated visual analogue scale, and also owner's global assessment of treatment efficacy. Twenty‐two animals completed the study. Pruritus and CADESI‐04 scores decreased significantly after one week or month of treatment, respectively, and remained stable for six months. Owner's global assessment score was 2.15±1.15 for all the animals in the study. In conclusion, systemic administration of allogeneic cAd‐MSCs appeared to be a simple therapy with positive outcome in the remission of clinical signs for AD refractory to conventional medications, for at least six months and with no adverse events.

Osteoarthritis (OA) commonly causes lameness in the horse and has a great impact in performance animals. Due to the limitations of current medical therapies, allogenic mesenchymal stem cells (MSCs) may become an alternative method to control inflammation, reduce tissue damage and pain, and therefore improve lameness. We present the results of a regulatory clinical trial testing adipose derived MSCs (Horse Allo 20) in veterinary (Agencia Española del Medicamento y Productos Sanitarios, AEMPS, Spanish Medicines Agency, Reference number 325/ECV) involving a total number of 80 participants and with 90 days of follow-up period. The manufacturing process of Horse Allo 20 was robust with no influence of the adipose tissue donor (gender, age or breed), sample origin (intraperitoneal or subcutaneous) or storage conditions (fresh versus frozen product presentations) on the quality, safety and efficacy of the drug product. An in vivo safety study showed that local and systemic tolerance was safe even after repeated intra-articular (IA) administration (three injections). An in vivo efficacy study demonstrated the efficacy of the treatment after one or two injections by a reduction in lameness (P<0.05) for an extended period of time (90 days), decreasing the need for prolonged local and/or systemic anti-inflammatory therapies and their well-known deleterious effects and toxicities.

Background: The ability of optical coherence tomography (OCT) to visualise macrophages in vivo in coronary arteries is still controversial. We hypothesise that imaging of macrophages in OCT could be enhanced by means of superparamagnetic nanoparticles. Methods: We compared the optical backscattering and attenuation of cell pellets containing RAW 264.7 macrophages with those of macrophagic cell pellets labelled with very small superparamagnetic oxydised nanoparticles (VSOP) by means of light intensity analysis in OCT. The labelled macrophages were incubated with VSOP at a concentration of 1 mM Fe, corresponding to intracellular iron concentrations of 8.8 pg/cell. To study the effect of intracellular accumulation on the backscattering, VSOP dilutions without cells were also compared. OCT pullbacks of the PCR tubes containing the cell pellets were obtained and light intensity analysis was performed on raw OCT images in polar view, after normalisation by the backscattering of the PCR tube. The backscattering was estimated by the peak normalised intensity, whilst the attenuation was estimated by the number of pixels between the peak and the normalised intensity 1 (peak-to-one). Results: VSOP-loaded macrophages have higher backscattering than the corresponding unlabelled macrophages (peak normalised intensity 6.30 vs. 3.15) with also slightly higher attenuation (peak-to-one 61 vs. 66 pixels). The backscattering of the nanoparticles in suspension was negligible in the light intensity analysis. Conclusions: VSOP increase significantly the optical backscattering of macrophages in the near-infrared region, with minimal increase in signal attenuation. This finding enables the enhancement of macrophages in conventional OCT imaging with an easily implementable methodology. Background: The ability of optical coherence tomography (OCT) to visualise macrophages in vivo in coronary arteries is still controversial. We hypothesise that imaging of macrophages in OCT could be enhanced by means of superparamagnetic nanoparticles. Methods: We compared the optical backscattering and attenuation of cell pellets containing RAW 264.7 macrophages with those of macrophagic cell pellets labelled with very small superparamagnetic oxydised nanoparticles (VSOP) by means of light intensity analysis in OCT. The labelled macrophages were incubated with VSOP at a concentration of 1 mM Fe, corresponding to intracellular iron concentrations of 8.8 pg/cell. To study the effect of intracellular accumulation on the backscattering, VSOP dilutions without cells were also compared. OCT pullbacks of the PCR tubes containing the cell pellets were obtained and light intensity analysis was performed on raw OCT images in polar view, after normalisation by the backscattering of the PCR tube. The backscattering was estimated by the peak normalised intensity, whilst the attenuation was estimated by the number of pixels between the peak and the normalised intensity 1 (peak-to-one). Results: VSOP-loaded macrophages have higher backscattering than the corresponding unlabelled macrophages (peak normalised intensity 6.30 vs. 3.15) with also slightly higher attenuation (peak-to-one 61 vs. 66 pixels). The backscattering of the nanoparticles in suspension was negligible in the light intensity analysis. Conclusions: VSOP increase significantly the optical backscattering of macrophages in the near-infrared region, with minimal increase in signal attenuation. This finding enables the enhancement of macrophages in conventional OCT imaging with an easily implementable methodology.