This work reports important advances in the study of magnetic nanoparticles (MNPs) related to their application in different research fields such as magnetic hyperthermia. Nanotherapy based on targeted nanoparticles could become an attractive alternative to conventional oncologic treatments as it allows a local heating in tumoral surroundings without damage to healthy tissue. RGD-peptide-conjugated MNPs have been designed to specifically target αVβ3 receptor-expressing cancer cells, being bound the RGD peptides by “click chemistry” due to its selectivity and applicability. The thermal decomposition of iron metallo-organic precursors yield homogeneous Fe3O4 nanoparticles that have been properly functionalized with RGD peptides, and the preparation of magnetic fluids has been achieved. The nanoparticles were characterized by transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), electron magnetic resonance (EMR) spectroscopy and magnetic hyperthermia. The nanoparticles present superparamagnetic behavior with very high magnetization values, which yield hyperthermia values above 500 W/g for magnetic fluids. These fluids have been administrated to rats, but instead of injecting MNP fluid directly into liver tumors, intravascular administration of MNPs in animals with induced colorectal tumors has been performed. Afterwards the animals were exposed to an alternating magnetic field in order to achieve hyperthermia. The evolution of an in vivo model has been described, resulting in a significant reduction in tumor viability.
Background: Lately, major advances in crucial aspects of magnetic hyperthermia (MH) therapy have been made (nanoparticle synthesis, biosafety, etc.). However, there is one key point still lacking improvement: the magnetic field-frequency product (H × f = 4.85 × 108 Am−1s−1) proposed by Atkinson–Brezovich as a limit for MH therapies. Herein, we analyze both local and systemic physiological effects of overpassing this limit. Methods: Different combinations of field frequency and intensity exceeding the Atkinson–Brezovich limit (591–920 kHz, and 10.3–18 kA/m) have been applied for 21 min to WAG/RijHsd male rats, randomly distributed to groups of 12 animals; half of them were sacrificed after 12 h, and the others 10 days later. Biochemical serum analyses were performed to assess the general, hepatic, renal and/or pancreatic function. Results: MH raised liver temperature to 42.8 ± 0.4 °C. Although in five of the groups the exposure was relatively well tolerated, in the two of highest frequency (928 kHz) and intensity (18 kA/m), more than 50% of the animals died. A striking elevation in liver and systemic markers was observed after 12 h in the surviving animals, independently of the frequency and intensity used. Ten days later, liver markers were almost recovered in all of the animals. However, in those groups exposed to 591 kHz and 16 kA/m, and 700 kHz and 13.7 kA/m systemic markers remained altered. Conclusions: Exceeding the Atkinson–Brezovich limit up to 9.59 × 109 Am−1s−1 seems to be safe, though further research is needed to understand the impact of intensity and/or frequency on physiological conditions following MH.
Surgery under ischemic conditions, lasting up to 3 h, is routinely performed in orthopedic surgery, causing undesirable injury due to ischemia-reperfusion syndrome, with short and medium-term functional repercussions. To date, there is no established prophylactic treatment. In this work we evaluated folinic acid (FA) in a rodent model of lower limb ischemia-reperfusion (IRI-LL). 36 male WAG rats underwent 3 h of lower limb ischemia. In the saline group, rats received intraperitoneal administration of saline (used as vehicle for treatment). In the experimental group, rats were pretreated with FA (2.5 mg/kg) before the end of ischemia. After ischemia, animals were sacrificed at 3 h, 24 h or 14 days (for biochemical determination (Na+, K+, Cl-, urea, creatinine, CK, LDH, ALP, ALT, and AST), pathological assessment, or functional study using the rotarod test; respectively). Another six animals were used to establish the reference values. The prophylactic administration of FA significantly reduced the elevation of biochemical markers, especially those that most directly indicate muscle damage (CK and LDH). In addition, it also improved direct tissue damage, both in terms of edema, weight, PMN infiltrate and percentage of damaged fibers. Finally, the administration of FA allowed the animals to equal baseline values in the rotarod test; what did not occur in the saline group, where pre-ischemia levels were not recovered. Following 3 h of lower limb ischemia, FA minimizes the increase of CK and LDH, as well as local edema and leukocyte infiltration, allowing a faster recovery of limb functionality. Therefore, it could be considered as a prophylactic treatment when tourniquet is used in clinics.
Current methodology described to mimic lower limb ischaemia–reperfusion injury (LL-IRI) does not accurately define the procedures and pressures exerted to induce and maintain ischaemia. In this piece of work, we propose a well-defined and detailed rat model that simulates the conditions established in clinical practice guidelines for tourniquet application and allows us to test treatments that aim to prevent/reduce LL-IRI. Eighty-six male WAG/RijHsd rats were subjected to hind limb IRI (LL-IRI), using a mechanical system applying a 1 kg tension to induce and maintain ischemia for 2 or 3 h, and assessed the damage caused by reperfusion at biochemical and muscular levels at different time points. At the biochemical level, both 2 and 3 h of ischemia induced changes (except for electrolyte levels); 3 h of ischemia induced greater changes in specific markers of muscular damage: creatine kinase (CK) and lactate dehydrogenase (LDH). At the histopathological level, 3 h of ischemia and 24 h of reperfusion was associated with an increase in hind limb girth, cross-sectional area, and weight and presence of neutrophils, as well as histological damage in more than 60% of muscle fibres. Our model allows to reliably reproduce the damage associated with the use of a pneumatic tourniquet. CK and LDH, as well as measures of tissue damage, allow to define and characterize the response to LL-IRI-related damage. A period of 3 h of ischemia followed by 3 h of reperfusion caused only local damage but showed greater sensitivity to detect differences in future studies on prophylactic treatments against LL-IRI.
En la atención asistencial, las habilidades de comunicación resultan fundamentales en el quehacer de los profesionales de la salud. La adquisición adecuada de dichas habilidades por parte del alumnado ha de ser uno de los objetivos de los equipos docentes. Conscientes de esta necesidad, en el grado en odontología de la UPV/EHU, se está llevando a cabo un proyecto de innovación educativa impulsando la labor y coordinación horizontal y vertical de los equipos docentes, dando lugar a las siguientes acciones: i, definición de una guía de habilidades comunicacionales; ii, diseño de actividades complejas basadas en escenarios realistas, implementadas mediante metodologías activas; iii, evaluación continua con la pertinente retroalimentación; y iv, seguimiento de todo el proceso con registro de evidencias. Tras un periodo de dos años, dicha evaluación está permitiendo tomar conciencia de los avances y dificultades presentes, tanto en el proceso como en la adquisición de algunos de los resultados de aprendizaje. La discusión, reflexión y consenso de los equipos docentes, intra e interasignatura, ha dado lugar a la mejora de las guías docentes, al rediseño de algunas de las actividades académicas, a un mayor grado de colaboración para la mejora de documentos de comunicación (ej.: consentimiento informado, elaboración de informes médicos) y para unificar criterios de evaluación, e, incluso, al diseño de talleres formativos sobre comunicación dirigidos al profesorado. Todo ello traerá consigo un impacto educativo, fruto del esfuerzo de los componentes de dichos equipos docentes que, sin duda, redundará en beneficio de la atención de los pacientes. In healthcare, communication skills are essential in the work of health professionals. The suitable acquisition of these skills by the students must therefore be one of the objectives of the teaching teams. Aware of this need, in the degree in dentistry at the UPV/EHU, an educational innovation project is being carried out by promoting the horizontal and vertical coordination and work of teaching teams, which has led to the following actions: i, definition of a communication skills guide; ii, design of complex activities based on realistic scenarios, implemented using active methodologies; iii, continuous assessment with pertinent feedback; and iv, monitoring of the entire process with evidence record. After a period of two years, we are becoming aware of the advances and difficulties present, both in the process and in the acquisition of some of the learning outcomes. The discussion, reflection and consensus of the teaching teams, intra and intersubject, has led to the improvement of the teaching guides, the redesign of some of the academic activities, a greater degree of collaboration for the improvement of communication documents (eg., informed consent, preparation of medical reports) and to unify evaluation criteria, and even the design of training workshops on communication aimed at teachers. All of this will have an educational impact, as a result of the efforts of the members of the teaching teams, that will undoubtedly benefit patient care.
Intestinal ischemia-reperfusion injury (i-IRI) is a rare disorder with a high mortality rate, resulting from the loss of blood flow to an intestinal segment. Most of the damage is triggered by the restoration of flow and the arrival of cytokines and reactive oxygen species (ROS), among others. Inactivation of these molecules before tissue reperfusion could reduce intestinal damage. The aim of this work was to analyze the preventive effect of allopurinol and nitroindazole on intestinal mucosal damage after i-IRI. Wag/RijHsd rats were subjected to i-IRI by clamping the superior mesenteric artery (for 1 or 2 h) followed by a 30 min period of reperfusion. Histopathological intestinal damage (HID) was assessed by microscopic examination of histological sections obtained from injured intestine. HID was increased by almost 20% by doubling the ischemia time (from 1 to 2 h). Nitroindazole reduced HID in both the 1 and 2 h period of ischemia by approximately 30% and 60%, respectively (p < 0.001). Our preliminary results demonstrate that nitroindazole has a preventive/protective effect against tissue damage in the early stages of i-IRI. However, to better understand the molecular mechanisms underlying this phenomenon, further studies are needed.
Background: New therapeutic approaches are an essential need for patients suffering from colorectal cancer liver metastases. Curcumin, a well-known plant-derived polyphenol, has been shown to play a role in the modulation of multiple signaling pathways involved in the development and progression of certain cancer cells in vitro. This study aims to assess the anti-tumor effect of curcumin on CC531 colorectal cancer cells, both in vitro and in vivo. Methods: On CC531 cultures, the cell viability and cell migration capacity were analyzed (wound healing test) 24, 48, and 72 h after treatment with curcumin (15, 20, 25, or 30 µM). Additionally, in WAG/RijHsd tumor-bearing rats, the total and individual liver lobe tumor volume was quantified in untreated and curcumin-treated animals (200 mg/kg/day, oral). Furthermore, serum enzyme measurements (GOT, GPT, glucose, bilirubin, etc.) were carried out to assess the possible effects on the liver function. Results: In vitro studies showed curcumin’s greatest effects 48h after application, when all of the tested doses reduced cell proliferation by more than 30%. At 72 h, the highest doses of curcumin (25 and 30 µM) reduced cell viability to less than 50%. The wound healing test also showed that curcumin inhibits migration capacity. In vivo, curcumin slowed down the tumor volume of liver implants by 5.6-fold (7.98 ± 1.45 vs. 1.41 ± 1.33; p > 0.0001). Conclusions: Curcumin has shown an anti-tumor effect against liver implants from colorectal cancer, both in vitro and in vivo, in this experimental model.
Background: Due to their self-renewal, proliferation, differentiation, and angiogenesis-inducing capacity, human adipose mesenchymal stem cells (AMSC) have potential clinical applications in the treatment of limb ischemia. AMSC from healthy donors have been shown to induce neovascularization in animal models. However, when cells were obtained from donors suffering from any pathology, their autologous application showed limited effectiveness. We studied whether liposuction niche and obesity could determine the regenerative properties of cells meaning that not all cell batches are suitable for clinical practice. Methods: AMSC obtained from 10 donors, obese and healthy, were expanded in vitro following a good manufacturing practice-like production protocol. Cell viability, proliferation kinetics, morphological analysis, phenotype characterization, and stemness potency were assessed over the course of the expansion process. AMSC selected for having the most suitable biological properties were used as an experimental treatment in a preclinical mouse model of hind limb ischemia. Result: All cell batches were positively characterized as mesenchymal stem cells, but not all of them showed the same properties or were successfully expanded in vitro, depending on the characteristics of the donor and the extraction area. Notably, AMSC from the abdomen of obese donors showed undesirable biological properties. AMSC with low duplication times and multilineage differentiation potential and forming large densely packed colonies, were able, following expansion in vitro, to increase neovascularization and repair when implanted in the ischemic tissue of mice. Conclusion: An extensive AMSC biological properties study could be useful to predict the potential clinical efficacy of cells before in vivo transplantation. Thus, peripheral ischemia and possibly other pathologies could benefit from stem cell treatments as shown in our preclinical model in terms of tissue damage repair and regeneration after ischemic injury.
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