Stereological and Morphometric Study of Type 3 Collagen Formation in the Cutaneous Wounds of Diabetic Mice Treated with Mesenchymal Stem Cells

Introduction: Wound healing is a progressive, essential and complex physiological process that occurs as a restorative response after a tissue injury. It involves three phases: inflammation, proliferation and maturation. Exogenous, endogenous and pathological factors may interfere in the cicatricial process in humans and animals by altering the balance between the synthesis, degradation and remodelling of collagen and elastic fibres. Diabetes mellitus is a progressive metabolic disease that alters elastogenesis and collagenesis and induces delays in the healing process. Scientific evidence suggests that mesenchymal stem cells modulate the cicatricial response. Thus the objective of this work was to perform stereological and morphometric analysis to determine the formation of dermal fibres in cutaneous fragments of a murine model of diabetes mellitus.Materials, Methods & Results: Histological sections were obtained from the cutaneous wounds of diabetic mice. The cutaneous wounds were previously treated with autogenous mesenchymal stem cells, physiological solution or polyurethane membrane. The histological sections were subsequently processed and stained for type 1 and 3 collagen fibres and elastic fibres using Picrosirius Red and Weigert staining, respectively. Histological sections stained with Picrosirius Red presented three types of birefringence under polarised light microscopy that corresponded to red colours for type 1 collagen and green and yellow colours for type 3 collagen. Weigert staining presented three colours for histological structures under white light microscopy that corresponded to black colours for elastic fibres, variations in colour from pink to purple for other structures and dermal attachments. The elastic fibres, represented by a black colour, presented in a heterogeneous form and were either identified as thin, punctiform or rectangular fibres or as elastic agglomerates. A greater volume of elastic fibres was observed in the superficial dermis than in the deep dermis, arranged irregularly. These fibres were organised longitudinally to the dermo-epidermal junction and surrounding the blood vessels and hair follicles. The images obtained were evaluated using the Cavalieri principle of stereology to obtain quantitative data in three-dimensions (3D), represented by the volume of the dermal fibres, and by the colour segmentation method. The K-means clustering plug-in in Image J® was used to quantify the area of the dermal fibres in the cutaneous wounds after the proposed dermatological treatments. A total of 90 images were obtained and analysed. No statistically significant differences (P > 0.01) were observed in the volume or area of type 1 collagen fibres between the treatment groups. Significant differences (P < 0.01) were only identified for the volumes and areas of type 3 collagen, with treated animals also presenting lower mean values for the volume and area of elastic fibres compared to the control group.Discussion: The preponderance of type 3 immature collagen in the cutaneous wounds of animals treated with stem cells indicates active collagenase and greater fibroblastic activity, which is probably induced by stem cells. Diametrically, the identification of lower levels of elastic fibres in the cutaneous fragments treated with stem cells suggests that cell therapy does not contribute satisfactorily to elastogenesis. Previous reports suggested that mesenchymal stem cells may decrease elastin synthesis, and such a situation may have occurred in this study. The autologous mesenchymal stem cells increased the formation of collagen fibres in diabetic mice at the detriment of the formation of elastic fibres, thus suggesting active early collagen in the first 2 weeks of the cicatricial process

Xenogeneic Mesenchymal Stem Cells in the Formation of Hyaline Cartilage in Osteochondral Goat Failure

Background: Osteochondral knee failures are among the most common causes of disability among the elderly human population and animal athletes. The xenogeneic transplantation of mesenchymal stem cells is a questionable therapeutic alternative that, despite the low expression of Major Histocompatibility Complex type II by these cells, still has relevantuncertainties about the safety and clinical efficacy. The main objective of the present study was to investigate whether the xenogeneic transplantation of mesenchymal stem cells induces hyaline cartilage formation, without histopathological evidence of rejection, in osteochondralfailures of goats.Materials, Methods & Results: Five female goats were used, submitted to three surgical osteocondral failures in the right knee, treated with xenogenic mesenchymal stem cells of dental pulp, xenogenic platelet-rich plasma and hemostatic sponge of hydrolyzed collagen, respectively. The lesions were evaluated after 60 days of treatment, aiming to identify thepresence of hyaline cartilage or fibrocartilage and the subchondral bone pattern (regenerated or disorganized). Transplantation of xenogenic mesenchymal stem cells induced predominant formation of hyaline cartilage (P 0.05). Macroscopically, the lesions of the stem cell treated group showed formation of firm repair tissue, opaque staining, integrated with adjacent cartilage and with the failure filling almost completely. The groups treated with PRP and hemostatic sponge of hydrolyzed collagen presented, on average, partial filling of the lesion, with irregular shape and darkened coloration.Discussion. The absence of macroscopic and histopathological evidences of an inflammatory process on the surface and in the internal portion of the osteochondral lesions treated with xenogeneic stem cells, probably due to the low expression of Major Histocompatibility Complex type II by these cells, which would theoretically induce low rejection response. Such observations are of great importance, since graft-versus- host disease syndrome is a serious condition, responsible for the low therapeutic efficacy with transplantation of cells or grafts in humans. The formation of fibrocartilage, although without macro and microscopic evidence of degeneration or necrosis, in the osteochondral failures treated with PRP and hemostatic collagen sponge suggest that paracrine factors of the local microenvironment of the osteochondral failure are possibly responsible for the formation of fibrocartilaginous tissue or by inhibition of normal cartilage formation. The fibrocartilage formed in the Plasmaand Control groups, contributed to the commitment in the filling of the lesion, contrasting with the almost complete fill of the lesions treated with stem cells. The xenotransplantation of mesenchymal stem cells induced formation of hyaline cartilage and did not promote histopathological evidence of rejection in osteochondral lesions of goat knees. The treatments with PRP and hemostatic sponge of hydrolyzed collagen induced greater formation of fibrocartilaginous cartilaginous surface in the osteochondral failures

Isolation, Expansion, Differentiation and Growth Kinetics Essay in Mesenchymal Stem Cells Culture from the Bone Marrow of Collared Peccaries (Tayassu tajacu)

Background: There are few studies on stem cell isolation in wild animals that provide isolation and culture protocols of these cells in vitro. Among the wild species studied, we present the collared peccary (Tayassu tajacu) as a model with potential to obtain and use MSC in preclinical studies. These animals are phylogenetically close to the domestic pig, popularly known as peccaries and found naturally in South America, Central America and the South of the United States. The aim of the present study was to establish a protocol for the isolation, in vitro cell expansion, differentiation and assessment of the stromal MSC growth curve before and after thawing.Materials, Methods &amp; Results: Mesenchymal stem cells (MSC) from collared peccary bone marrow (Tayassu tajacu) were isolated and expanded by centrifuge in Ficoll® solution and cultured in DMEM® High Glucose medium. The culture was assessed by assays of colony forming units CFU-F and growth curve by saturation (GCS). Cultures in the third passage, with 70% confluence, were replicated at 105 cells/mL concentration in the culture media to induce osteogenic cell differentiation and adipogenic cell differentiation, respectively. The MSC were frozen in nitrogen for 40 days, thawed and re-assessed for cell viability and GCS.Discussion: The bone marrow collected presented high mononuclear cellularity, with a mean variability of 94.5% and 60.83 ± 4.27 UFC were identified in the samples and cells with fibroblast-like-cell morphology were observed. When they were expanded, the mean cell viability was 95%, the mean cell concentration obtained was 233.31 ± 20.04 cells per 25cm2 bottle and the culture reached the growth plateau in GCS between the 13th and 16th day. The osteoblastic cell differentiation assay showed after 18 days, morphology similar to osteoblasts, with irregular cytoplasm limits, cell prolongation formation and flattened appearance. After staining with Alizarin Red, the nucleus presented a wine red coloring and the cytoplasm, more basophilic and well-defined, with calcium deposits inside the cells. The cultures submitted to adipogenic differentiation were large, hexagonal, irregular and presented birrefringent cytoplasm granules after the third week of culture. When stained with Oil Red it was observed that the cytoplasm granules were scattered small fat vacuoles and stained maroon. The viability after thawing was 78% and the mean cell concentration obtained in GCS was 199.71 ± 14.72 cells per 25 cm2 bottle. The curves reached the saturation plateau early, on the eighth day of observation. From then onwards the cultures entered became exhausted and the cell concentration of the samples decreased progressively until minimum values. These results showed the presence of a well-defined MSC population in the collared peccary bone marrow with a high rate of replication in vitro and potential for differentiation confirmed by the adipogenic and osteogenic lines. The cryopreservation technique adopted presented satisfactory results, but indicated a significant cell stress after thawing that justifies investigation of the apoptosis rates induced post thawing in the species. Furthermore, the bone marrow collection did not harm the animals and the facility of stromal MSC isolation and culture qualifies the collared peccary as a viable alternative model to obtain MSC and for studies in the area of cell therapy

COVID-19 e dengue: ocorrência síncrona, em cidade endêmica, no sul da Bahia: COVID-19 and dengue: synchronous occurrence in an endemic city in southern Bahia

No Brasil, a pandemia provocada pelo novo coronavírus, SARS-Cov-2, teve início em fevereiro de 2020, desde então, vem provocando um aumento de novos casos acompanhados por um elevado número de óbitos. Aliado ao avanço dessa nova doença está o agravo de caráter endêmico responsável por eventos de epidemias cíclicas, como a dengue, provocada por um arbovírus. Devido a semelhança entre sintomas clínicos da dengue e da COVID, essa dificuldade em realizar diagnósticos pode afetar negativamente estudos que apontem correlação entre a COVID-19 e a dengue, dessa forma, esse trabalho visa apontar a ocorrência de infecções síncronas para esses dois agravos e quais suas correlações clínicas. Foram utilizados pacientes que estavam positivos, laboratorialmente, para COVID-19 e dengue, no mesmo período, na cidade de Itabuna/BA em 2020. Observou-se predomínio de pacientes masculinos e uma correlação entre sintomas, sendo febre e distúrbios gustativos/olfatórios os sintomas mais frequentes para a infecção síncrona. Não foi observado um predomínio em relação a idade, não sendo possível avaliar um grupo de risco específico. Ademais, dentre os casos encontrados, não se verificou nenhum óbito. Com esse trabalho se concluiu que embora a ocorrência síncrona de COVID e dengue seja positiva, a sobrecarga do serviço de saúde provocou uma subnotificação de dengue, dispondo assim uma necessidade maior de estudos que visem elucidar o mecanismo de ação e interação desses agravos, a fim de fornecer um atendimento de melhor qualidade para a população

Characterization and plasticity of wharton's jelly mesenchymal stem cells of goat

Mesenchymal stem cells (MSCs), obtained from several anatomical sites, have already been described, characterized and used in therapeutic models for tissue repair. The umbilical cord mesenchymal stem cells, represented by cells from arteries and veins walls, as well as Wharton's jelly are easy to be obtained, highly available, require no invasive procedure, do not present risk to donors and do not present ethical limitation. The aim of this research was to analyze the plasticity of Wharton's jelly mesenchymal stem cells (WJ-MSCs) of goat, evaluating their behavior in vitro and characterizing them immunophenotypically. Thus, tests were performed on colony forming units, viability and cell growth curve, flow cytometry analysis and plasticity potential. Goat umbilical cord matrix cells exhibited fibroblastoid morphology with colony formation and self-renewal ability, always maintaining their undifferentiated state up to the eighth passage (P8). The growth curve kinetics exhibited the LAG, LOG, and DECAY phases, without displaying a PLATEAU phase. The plasticity assay demonstrated positive differentiation for osteogenic, adipogenic and chondrogenic lines, characterized by the synthesis of intracytoplasmic granules or extracellular matrix with the presence of calcium, lipids and proteoglycans. Flow cytometry demonstrated the expression of CD90 and CD105; absence of CD14 expression.  It is concluded that the cell population isolated from the Wharton's  jelly of goat constitutes a representative sample of mesenchymal stem cells, with great possibilities in the field of regenerative and reproductive medicine

The effect of mesenchymal stem cells combined with platelet-rich plasma on skin wound healing

INTRODUCTION: Mesenchymal stem cells (MSCs) are multipotent stem cells that have the potential of proliferation, high self-renewal, and the potential of multilineage differentiation. The differentiation potential of the MSCs in vivo and in vitro has caused these cells to be regarded as potentially appropriate tools for wound healing. After the burn, trauma or removal of the tumor of wide wounds is developed. Although standard treatment for skin wounds is primary healing or skin grafting, they are not always practical mainly because of limited autologous skin grafting. EVIDENCE ACQUISITIONS: Directory of Open Access Journals (DOAJ), Google Scholar, PubMed (NLM), LISTA (EBSCO), and Web of Science have been searched. EVIDENCE SYNTHESIS: For clinical use of the MSCs in wound healing, two key issues should be taken into account: First, engineering biocompatible scaffolds clinical use of which leads to the least amount of side effects without any immunologic response and secondly, use of stem cells secretions with the least amount of clinical complications despite their high capability of healing damage. CONCLUSION: In light of the MSCs' high capability of proliferation and multilineage differentiation as well as their significant role in modulating immunity, these cells can be used in combination with tissue engineering techniques. Moreover, the MSCs' secretions can be used in cell therapy to heal many types of wounds. The combination of MSCs and PRP aids wound healing which could potentially be used to promote wound healing

Uso de drogas e o aumento das infecções sexualmente transmissíveis: uma revisão sistemática: Drug use and the increase in sexually transmitted infections: a systematic review

Populações de usuários de drogas têm sido associadas a epidemias de infecções ou Infecções Sexualmente Transmissíveis, especialmente a infecção pelo HIV (que está associada a drogas injetáveis, uso de equipamentos contaminados para drogas injetáveis e sexo inseguro). A droga mais associada às DSTs é a cocaína fumável de base livre (crack), devido ao aumento dos comportamentos sexuais de risco. Diante disso, o presente estudo teve como objetivo compreender o impacto do uso de drogas no aumento das infecções sexualmente transmissíveis. Para isso, adotou-se como metodologia a revisão sistemática de literatura, realizando buscas nas bases de dados Scielo, Pubmed e BVS/Medline a partir do uso de descritores DeCS/MeSH e aplicação de critérios de inclusão e exclusão. A partir da análise e interpretação dos dados, concluiu-se que que pessoas que fazem uso abusivo de drogas lícitas ou ilícitas, sejam elas mulheres, homens, adolescentes, jovens, adultos, idosos, em situação de rua ou não, tendem a desenvolver comportamentos vulneráveis que pode resultar em IST. Somado a isso, enquanto comportamento de risco, tem-se a preferência por não usar preservativo, seja em relações sexuais com pessoas monogâmicas como com dois ou mais parceiros. Nesses casos, tanto o uso exacerbado de drogas como a falta de informação sobre comportamento sexual demonstram-se insuficientes