Characterization of the host tissue response induced by a biosynthetic material composed of poly (4-hydroxybutyrate)

Biomaterial-associated infections and bacterial resistance to antibiotics represent two of the major causes of implant failure. Pre-clinical and clinical studies have associated the use of biosynthetic surgical mesh materials composed of poly (4-hydroxybutyrate) (P4HB) with decreased surgical site infection (SSI) and an improved long-term remodeling response. The mechanisms driving these beneficial effects of P4HB remain unknown. 4-hydroxybutyrate (4HB), the main degradation product of P4HB, is an endogenous short chain fatty acid (SCFA) that has been exhaustively studied for its role as a modulator of the neurotransmitter γ-aminobutyric acid (GABA) in the central nervous system (CNS) and as a modulator of reactive oxygen species (ROS) in endothelium. Other functions of 4HB within non-CNS tissues have been less studied; however, this SCFA is a hydroxylated form of butyrate, a known histone deacetylase (HDAC) inhibitor, which is secreted by commensal bacteria within the gastrointestinal tract. Butyrate exerts its immunomodulatory functions by suppressing pro-inflammatory macrophage activation and promoting antimicrobial peptide (AMP) secretion. However, the immunomodulatory effects of 4HB upon cells of the immune system and the ability of 4HB to induce the expression of AMP have not been studied. The present dissertation evaluates the 4HB-mediated effects upon macrophage expression. The molecular mechanisms by which a specific AMP, cathelicidin LL-37, is expressed are described. A rat model of a partial thickness abdominal wall defect and a rat model of deliberate contamination in a subcutaneous tissue pocket are used to evaluate the host macrophage response and the expression of cathelicidin LL-37 in the presence of P4HB surgical mesh. 4HB promotes a pro-remodeling, regulatory phenotype and increases expression of AMP in subjected macrophages. The associated molecular mechanism involves transcriptional activation of cathelicidin LL-37 through MAP-kinase and NF-κB pathways. In vivo, P4HB mitigates the acute, pro-inflammatory host response and provides an increased resistance to bacterial contamination. The results of this work expand the understanding of the biologic activity of 4HB in cells of the immune system and show its potential to promote a constructive tissue remodeling effect for regenerative medicine applications

Matrix construction as dermal substitutes: potential application in skin regeneration

La pérdida de grandes porciones de piel limita su capacidad de regeneración, haciendo difícil su tratamiento. Mediante la ingeniería de tejidos se han desarrollado sustitutos dérmicos que promueven la regeneración; sin embargo, es necesario hallar un material para el crecimiento de fibroblastos que sea un sustituto dérmico adecuado. En este trabajo se construyeron matrices tridimensionales porosas de colágeno y colágeno-ácido hialurónico evaluando su potencial como sustituto dérmico. Las matrices se entrecruzaron con 1-etil-3-(3-dimetilaminopropil) carbodiimida hidrocloruro. Se evaluó la porosidad, se realizaron pruebas de degradación, evaluación de adherencia celular con fibroblastos humanos y, ensayos de viabilidad y proliferación. Las matrices presentaron poros de 50 μm de diámetro uniformemente distribuidos. Las matrices de colágeno y colágeno-ácido hialurónico (2:8 y 4:6) presentaron una degradación progresiva con pesos similares. Luego de 24 horas en cultivo, los resultados de la prueba de MTT mostraron que los fibroblastos en colágeno proliferaron; mientras que los fibroblastos en colágeno-ácido hialurónico no evidenciaron proliferación. Aunque la estructura porosa y la tasa de degradación de las matrices son similares, las de colágeno brindan mejores condiciones de adhesión y proliferación a los fibroblastos cultivados en comparación con las que tienen ácido hialurónico como adición, convirtiéndose en el mejor andamio para ser empleado como sustituto dérmico entre las matrices evaluadas.Wounds can cause loss of skin that limits the skin regeneration, making the treatment more difficult to address. The tissue engineering has developed skin substitutes that promote skin regeneration; however, it is imperative to find materials that allow fibroblast growth in order to find an appropriate skin substitute. The construction of tridimensional porous collagen and collagenhyaluronic acid matrixes crosslinked with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride is presented in order to evaluate their potential use in skin regeneration therapies. Matrix porosity was evaluated. Degradation tests, human fibroblast adherence, viability and proliferation tests were performed. Matrixes had a uniform distributed porosity with mean diameters of 50 μm. Both collagen and collagen-hyaluronic acid (2:8 and 4:6) matrixes presented a progressive degradation rate with similar weight. After 24 hours under culture, the number of fibroblasts seeded on collagen matrixes were doubled, while the number of fibroblast seeded on collagen-hyaluronic acid matrixes remained similar. Even though porous structure and degradation rate of different types of constructed matrixes in this study are similar, collagen matrixes offer better adhesion and proliferation conditions for seeded fibroblasts in comparison with hyaluronic acid added matrixes, making them the best scaffold to be employed as a dermic substitute among the matrixes compared here

Adipose tissue derived mesenchymal stem cells, isolation and differentiation into the osteogenic lineage

El tejido adiposo es una de las principales fuentes de células madre de fácil obtención y con alto potencial de diferenciación hacia linajes celulares especializados. Con el objetivo de estandarizar la obtención de estas células y dirigir su diferenciación hacia el linaje osteogénico, se utilizó tejido adiposo procedente de liposucción y de abdominoplastia. Se aplicaron métodos de disgregación mecánica y enzimática del tejido para obtener las células. La morfología celular obtenida fue similar a fi broblastos y a células madre reportadas por otros autores. Se encontró una mayor efi ciencia en el procesamiento del lipoaspirado en comparación con el tejido resultante de abdominoplastia, y la disgregación enzimática del tejido permitió una mayor liberación de células y una temprana adhesión al plato de cultivo. La inducción de las células madre derivadas de lipoaspirado hacia el linaje osteogénico permitió la observación, mediante tinción con alizarina roja S, de depósitos de calcio en la matriz extracelular en las células bajo condiciones de diferenciación, pero no en aquellas sin suplementos osteogénicos. Se obtuvieron cultivos de células madre derivadas de lipoaspirado con capacidad de diferenciación hacia el linaje osteogénico, a través de inducción controlada, que podrían ser utilizadas en la ingeniería de tejido óseo.Adipose tissue is one of the main sources of stem cells readily available and with a high potential to differentiate into specifi c mesenchymal and non-mesenchymal lineages. Therefore, to standardize the collection of these cells, adipose tissue from surgical liposuctions and abdominoplasty was used. Methods of enzymatic and mechanical digestion were used to release the cells. With regard to cell morphology, the cells displayed a fi broblast-like spindleshaped morphology as cited by other authors. There was a higher effi ciency in processing tissue from liposuctions compared with tissue from abdominoplasty. Likewise, the enzymatic digestion allowed faster initial cell adhesion than the mechanical digestion. Finally, calcium deposits were observed by alizarin red staining in cultures under osteogenic conditions, but were absent in cultures lacking osteogenic supplements. In conclusion, isolated adiposedderived stem cells were capable of osteogenic differentiation and therefore with potential applications in bone tissue engineering

Supracondylar fractures of the humerus in children aged 2-14 years. Demographic profile and therapeutic approach at a third-level hospital in Medellín, Colombia

ABSTRACT: Supracondylar fractures of the distal humerus are the most frequent injuries that require surgical treatment in the pediatric population. Reports on the demographic profile and the therapeutic approach of patients with these fractures in Medellín, Colombia, are limited. This study was carried out in order to know the local epidemiology of these lesions, and to detect during the follow-up the good therapeutic decisions and the mistakes, as a basis for more complex research. Materials and methods: A comprehensive search was conducted of electronic medical records at a thirdlevel hospital; 205 cases of supracondylar fractures of the humerus were found in children aged 2-14 years, admitted to the emergency service (Hospital Pablo Tobón Uribe) between January 2005 and September 2009. Demographic and therapeutic aspects were analyzed. Results: Average age was 6.6 years; 61.5% of the patients were males. In 62.4% fractures affected the left side. Classification (Gartland) was as follows: type I: 41.5%; type II: 12.2%; type III: 46.3%. Fractures were closed in 95.5% of the patients. Treatment was surgical in 103 patients (50.2%). Average time between admission and surgery was 6.7 hours. The most frequently used surgical technique was closed reduction with percutaneous fixation with crossed pins (45.6%). There were 31 cases of neurological injuries, 28 of which affected the ulnar nerve. Nine of the 31 were observed in the immediate postoperative evaluation and all of these occurred in patients treated with crossed pins. There were no vascular injuries or compartment syndromes. Conclusion: This series presents the current demographic profile of patients with supracondylar fractures of the distal humerus in children, as well as the therapeutic approaches in a third-level hospital in Medellín, Colombia. These results may be the basis for future more complex studies.RESUMEN: Las fracturas supracondíleas del húmero distal son las lesiones más frecuentes de tratamiento quirúrgico en la población pediátrica. Los informes sobre el perfil demográfico y el enfoque terapéutico de las mismas en Medellín son limitados; este trabajo se llevó a cabo para conocer la epidemiología local de estas lesiones y detectar en el seguimiento los aciertos y errores del tratamiento como base para desarrollar estudios de mayor complejidad. Materiales y métodos: mediante una búsqueda exhaustiva en los registros de historias clínicas electrónicas se encontraron 205 casos de fracturas supracondíleas del húmero en niños entre dos y 14 años que ingresaron al Servicio de Urgencias del Hospital Pablo Tobón Uribe entre enero de 2005 y septiembre de 2009. Se analizaron en ellas los aspectos demográficos y terapéuticos. Resultados: el 61,5% de los pacientes fueron varones, la media de la edad fue de 6,6 años, en 62,4% de los casos la fractura afectó el lado izquierdo. La clasificación (Gartland) fue como sigue: tipo I: 41,5%; tipo II: 12,2%; tipo III: 46,3%. El 95,6% fueron fracturas cerradas. Se hizo tratamiento quirúrgico en 103 casos (50,2%). El tiempo promedio entre el ingreso y la cirugía fue de 6,7 horas. La técnica quirúrgica más frecuente fue la reducción cerrada con fijación percutánea con clavos cruzados (45,6% de los casos). Se observaron 31 casos (15,1%) de lesiones neurológicas, 28 de ellas del nervio ulnar; nueve de las 31 lesiones se registraron en la evaluación posquirúrgica inmediata, todas ellas en pacientes tratados con clavos cruzados. No se registraron lesiones vasculares ni síndromes compartimentales. Conclusión: esta serie presenta el estado actual del perfil demográfico de los pacientes con fracturas supracondíleas del húmero distal en niños y de las modalidades de tratamiento en un hospital de tercer nivel de la ciudad de Medellín. Los resultados pueden ser la base para futuros estudios de mayor elaboración metodológica

Host macrophage response to injectable hydrogels derived from ECM and α-helical peptides

Tissue engineering materials play a key role in how closely the complex architectural and functional characteristics of native healthy tissue can be replicated. Traditional natural and synthetic materials are superseded by bespoke materials that cross the boundary between these two categories. Here we present hydrogels that are derived from decellularised extracellular matrix and those that are synthesised from de novo α-helical peptides. We assess in vitro activation of murine macrophages to our hydrogels and whether these gels induce an M1-like or M2-like phenotype. This was followed by the in vivo immune macrophage response to hydrogels injected into rat partial-thickness abdominal wall defects. Over 28 days we observe an increase in mononuclear cell infiltration at the hydrogel-tissue interface without promoting a foreign body reaction and see no evidence of hydrogel encapsulation or formation of multinucleate giant cells. We also note an upregulation of myogenic differentiation markers and the expression of anti-inflammatory markers Arginase1, IL-10, and CD206, indicating pro-remodelling for all injected hydrogels. Furthermore, all hydrogels promote an anti-inflammatory environment after an initial spike in the pro-inflammatory phenotype. No difference between the injected site and the healthy tissue is seen after 28 days, indicating full integration. These materials offer great potential for future applications in regenerative medicine and towards unmet clinical needs

Consumption of ground flaxseed for overweight individuals to lose weight

ABSTRACT: To describe changes in weight, body fat mass and food intake in overweight and obese people, who consumed 30g of ground flaxseed daily during eight weeks and to report the tolerance to this treatment. Materials and methods: It was an intervention study. A group of 10 overweight adults were selected to voluntarily consume 30g of ground flaxseed through eight weeks. They were asked not to change their usual food intake and their physical activity routine during the intervention. Food consumption, physical activity and anthropometric variables were measured at baseline, week four and week eight. Subject’s tolerance to consumption of ground flaxseed was measured each week. Results: No significant changes in weight (p=0,610), and body fat mass (p=0,866) were observed. Participants did not report adverse effects. Conclusions: Intake of 30 g of ground flaxseed daily for eight weeks, without reductions of caloric intake and without increases in physical activity didn’t show significant weight reductions in overweight individuals.RESUMEN: describir los cambios en el peso, el porcentaje de grasa corporal y la ingesta de alimentos de personas con sobrepeso y obesidad, que consumieron 30g diarios de linaza molida durante ocho semanas y reportar su tolerancia a este tratamiento. Materiales y métodos: se intervino un grupo de 10 participantes adultos con exceso de peso, voluntarios, quienes consumieron una dosis diaria de 30g de linaza molida durante ocho semanas, a quienes se les solicitó no modificar su ingesta usual de alimentos y no cambiar su patrón de actividad física durante la intervención. Se midieron variables antropométricas, de consumo de alimentos y de actividad física en las semanas cero, cuatro y ocho, y se evaluó semanalmente la aceptación y tolerancia al tratamiento. Resultados: al finalizar la intervención, los participantes no tuvieron cambios significativos en su peso (p=0,610), ni en su porcentaje de grasa corporal (p=0,866). No se presentaron efectos adversos. Conclusión: el consumo de 30g diarios de linaza molida durante ocho semanas, sin hacer reducciones en el consumo calórico y sin incrementos en la realización de actividad física, no permite reducciones de peso corporal en personas con exceso de peso

Effect of flaxseed consumption on lipid profile, the control of cancer and hormone replacement therapy in menopause : a systematic review of randomized controlled trials

ABSTRACT: To evaluate the effects of flaxseed consumption in changing the lipid profile, cancer control and hormone replacement therapy at menopause and andropause in individuals of all ages. Materials and methods: We conducted a systematic review of randomized controlled trials that examined the effects of flaxseed consumption on body weight reduction, change in blood lipid levels, cancer control and menopausal symptoms. We used Pub-Med, Lilacs, the libraries of PAHO and WHO, and clinical trials published in Cochrane between January 1, 2000 and June 30, 2010. The articles that met the inclusion criteria were assessed for methodological quality. Results: We included 49 articles. Studies reported that flaxseed consumption generates small changes in blood lipid concentrations, improvement in menopausal symptoms, promotes the reduction of tumor proliferation rates and increased apoptosis in breast and prostate cancer Conclusions: The results are not yet sufficient to recommend the use of flaxseed for the control of hypercholesterolemia in patients with dyslipidemia. The evidence favors flaxseed as an alternative adjuvant therapy for breast and prostate cancer treatment, and reduction of menopause symptoms.RESUMEN: evaluar los efectos del consumo de linaza sobre el perfil lipídico, control del cáncer y como reemplazo hormonal en la menopausia y en la andropausia. Materiales y métodos: se realizó una revisión sistemática de ensayos clínicos aleatorizados que examinaron los efectos del consumo de linaza sobre el peso corporal, la concentración de lípidos sanguíneos, el control del cáncer y los síntomas menopáusicos, usando las bases de datos de PubMed, Lilacs, OPS, OMS y Cochrane, publicados entre el 1 de enero de 2000 y el 30 de junio de 2010. A los artículos que cumplieron con criterios de inclusión se les evaluó su calidad metodológica. Resultados: fueron incluidos 49 artículos. Los estudios reportan que el consumo de linaza genera pequeños cambios en la concentración de los lípidos sanguíneos, mejora la sintomatología en mujeres menopáusicas, promueve la reducción de índices de proliferación tumoral y el aumento de apoptosis en cáncer de mama y próstata. Conclusiones: los resultados aún no son suficientes para recomendar el uso de la linaza para el control de la hipercolesterolemia en pacientes dislipidémicos. La evidencia favorece la linaza como una alternativa en la terapia coadyuvante del tratamiento del cáncer de mama y de próstata, y en la reducción de síntomas durante la menopausia

Matrix-Bound Nanovesicles: The Effects of Isolation Method upon Yield, Purity, and Function

Identification of matrix-bound nanovesicles (MBV) as ubiquitous components of the extracellular matrix (ECM) raises questions regarding their biologic functions and their potential theranostic application. Unlike liquid-phase extracellular vesicles (e.g., exosomes), MBV are tightly bound to the ECM, which makes their isolation and harvesting more challenging. The indiscriminate use of different methods to harvest MBV can alter or disrupt their structural and/or functional integrity. The objective of the present study was to compare the effect of various MBV harvesting methods upon yield, purity, and biologic activity. Combinations of four methods to solubilize the ECM (collagenase [COL], liberase [LIB], or proteinase K [PK] and nonenzymatic elution with potassium chloride) and four isolation methods (ultracentrifugation, ultrafiltration [UF], density barrier, and size exclusion chromatography [SEC]) were used to isolate MBV from urinary bladder-derived ECM. All combinations of solubilization and isolation methods allowed for the harvesting of MBV, however, distinct differences were noted. The highest yield, purity, cellular uptake, and biologic activity were seen with MBV isolated by a combination of liberase or collagenase followed by SEC. The combination of proteinase K and UF was shown to have detrimental effects on bioactivity. The results show the importance of selecting appropriate MBV harvesting methods for the characterization and evaluation of MBV and for analysis of their potential theranostic application

Soluciones terapéuticas para la reconstrucción de la dermis y la epidermis. Oportunidades en el medio antioqueño

En Antioquia, es necesario buscar una solución disponible, efectiva y económicamente viable para afrontar los problemas de la piel de los pacientes que, por accidentes o enfermedades, han disminuido su calidad de vida y se encuentran aislados a la espera de tratamientos que les permitan recuperar la funcionalidad de su cuerpo y les reduzcan los riesgos por la exposición de los tejidos internos. Las diferentes soluciones existentes en el mercado todavía no han llegado a superar algunos obstáculos tales como el cubrimiento de todas las extensiones, los altos costos, la funcionalidad de los tejidos restaurados, los rechazos de tipo inmune y la escasez de los sitios donantes. Este artículo presenta una revisión literaria que busca mostrar las diferentes alternativas de solución para pacientes con problemas de piel, dando énfasis en las soluciones clásicas aplicables y económicamente viables desde la ingeniería de tejidos en el sector antioqueño.In Antioquia (Colombia), there are many patients who suffer dermal injuries caused by accident or disease. Therefore, it is necessary to pursue available, effective and affordable solutions to overcome dermal problems. Physicians and patients are both expecting corrective treatments that can reduce inner tissue exposition and allow the possibility of recovering skin functionality. Although there are many solutions for skin replacement, some obstacles remain, such as: high costs, limited availability of skin for implantation in extended areas, adequate functionality of the restored tissue and immunological rejection. Due to these issues, this article presents some of the existing alternative solutions for patients with skin injuries, considering the histology and physiology of the skin, and regarding the classical and economically attainable solutions to be used in Antioquia

Spatiotemporal Characteristics of the Largest HIV-1 CRF02_AG Outbreak in Spain: Evidence for Onward Transmissions

Background and Aim: The circulating recombinant form 02_AG (CRF02_AG) is the predominant clade among the human immunodeficiency virus type-1 (HIV-1) non-Bs with a prevalence of 5.97% (95% Confidence Interval-CI: 5.41–6.57%) across Spain. Our aim was to estimate the levels of regional clustering for CRF02_AG and the spatiotemporal characteristics of the largest CRF02_AG subepidemic in Spain.Methods: We studied 396 CRF02_AG sequences obtained from HIV-1 diagnosed patients during 2000–2014 from 10 autonomous communities of Spain. Phylogenetic analysis was performed on the 391 CRF02_AG sequences along with all globally sampled CRF02_AG sequences (N = 3,302) as references. Phylodynamic and phylogeographic analysis was performed to the largest CRF02_AG monophyletic cluster by a Bayesian method in BEAST v1.8.0 and by reconstructing ancestral states using the criterion of parsimony in Mesquite v3.4, respectively.Results: The HIV-1 CRF02_AG prevalence differed across Spanish autonomous communities we sampled from (p < 0.001). Phylogenetic analysis revealed that 52.7% of the CRF02_AG sequences formed 56 monophyletic clusters, with a range of 2–79 sequences. The CRF02_AG regional dispersal differed across Spain (p = 0.003), as suggested by monophyletic clustering. For the largest monophyletic cluster (subepidemic) (N = 79), 49.4% of the clustered sequences originated from Madrid, while most sequences (51.9%) had been obtained from men having sex with men (MSM). Molecular clock analysis suggested that the origin (tMRCA) of the CRF02_AG subepidemic was in 2002 (median estimate; 95% Highest Posterior Density-HPD interval: 1999–2004). Additionally, we found significant clustering within the CRF02_AG subepidemic according to the ethnic origin.Conclusion: CRF02_AG has been introduced as a result of multiple introductions in Spain, following regional dispersal in several cases. We showed that CRF02_AG transmissions were mostly due to regional dispersal in Spain. The hot-spot for the largest CRF02_AG regional subepidemic in Spain was in Madrid associated with MSM transmission risk group. The existence of subepidemics suggest that several spillovers occurred from Madrid to other areas. CRF02_AG sequences from Hispanics were clustered in a separate subclade suggesting no linkage between the local and Hispanic subepidemics