RESUMO
The present work aims to investigate whether it is possible to identify and quantify the contributions of the interstitial fluid and the solid skeleton to the overall time-dependent behavior of tendons based on a single mechanical test. For this purpose, the capabilities of three different time-dependent models (a viscoelastic, a poroelastic and a poroviscoelastic) were investigated in the modeling of the experimental behavior obtained from semi-confined compression with stress relaxation tests transverse to collagen fibers. The main achieved result points out that the poroviscoelastic model was the only one capable to characterize both the experimental responses of the force and volume changes of the tissue samples. Moreover, further analysis of this model shows that while the kinematics of the sample are mainly governed by the fluid flow (pore pressure contribution of the model), the behavior intrinsically associated with the viscoelastic solid skeleton makes a significant contribution to the experimental force response. This study reinforces the importance of taking both the experimental kinematics and kinetics of tendon tissues into account during the constitutive characterization procedure.
Assuntos
Modelos Biológicos , Tendões , Elasticidade , Estresse Mecânico , ViscosidadeRESUMO
BACKGROUND/AIM: Tumor interstitial fluid (TIF), a component of the tumor microenvironment, is a valuable source of molecules and substances that help in diagnosis and prognosis of solid tumors. There is still no consensus on the optimal method for collecting TIF. Therefore, this study aimed to evaluate the effectiveness of a new method of collecting TIF in invasive ductal carcinoma (IDC) samples for cytokine interleukin 1ß (IL1ß) quantification. MATERIALS AND METHODS: Forty women allowed the collection of TIF using absorbent paper strips during the performance of the core biopsy. The samples were stored at a temperature of -80°C and then analyzed using an enzyme-linked immunoassay. RESULTS: The mean values for IL1ß and total protein were 11.39 mg/ml and 2.15 mg/ml, respectively. CONCLUSION: it was possible to quantify the cytokine IL1ß and the total protein concentration present in the tumor tissue through TIF collection with the use of absorbent paper filters, demonstrating the effectiveness of this new method in oncology.
Assuntos
Biomarcadores Tumorais/análise , Neoplasias da Mama/imunologia , Carcinoma Ductal de Mama/imunologia , Líquido Extracelular/imunologia , Interleucina-1beta/análise , Adulto , Idoso , Biópsia com Agulha de Grande Calibre , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Pessoa de Meia-Idade , Microambiente TumoralRESUMO
Cell migration is a process of crucial importance for the human body. It is responsible for important processes such as wound healing and tumor metastasis. Migration may occur in response to stimuli of chemical, physical and mechanical nature occurring in the cellular microenvironment. The interstitial flow (IF) can generate mechanical stimuli in cells that influence the cell behavior and interactions of the cells with the extracellular matrix (ECM). One of the phenomena is upstream migration, which is observed in some tumors. In this work, we present a new approach to study the adherent cell migration in a porous medium using a mechanobiological model, attempting to understand if upstream migration can be generated exclusively by mechanical factors. The influence of IF on the behavior of cells and the extracellular matrix was considered. The model is based on a system of coupled nonlinear differential equations solved by the finite element method. Several simulations were performed to study the upstream cell migration and evaluate the effects of pressure, permeability, ECM stiffness and cellular concentration variations on the cell velocity. The results indicated that upstream migration can occur in the presence of mechanical stimuli generated by IF and that the tested parameters have a direct influence on the cellular velocity, especially the pressure and the permeability.
Assuntos
Movimento Celular , Modelos Biológicos , Fenômenos Biomecânicos , Matriz Extracelular/metabolismo , Humanos , Microfluídica , Análise Numérica Assistida por Computador , Estresse MecânicoRESUMO
Protein malnutrition is a risk factor for developing visceral leishmaniasis. Because we previously demonstrated that protein malnutrition and infection with Leishmania infantum disrupts the splenic microarchitecture in BALB/c mice, alters T cell-subsets and increases splenic parasite load, we hypothesize that splenic microenvironment is precociously compromised in infected animals that suffered a preceding malnutrition. To evaluate this, we characterized the abundance of proteins secreted in the splenic interstitial fluid (IF) using an iTRAQ-based quantitative proteomics approach. In addition, local levels of pro-inflammatory and proliferation molecules were analyzed. Whereas well-nourished infected animals showed increased IL-1ß and IL-2 levels, malnourished-infected mice displayed significant reduction of these cytokines. Remarkably, a two-weeks infection with L. infantum already modified protein abundance in the splenic IF of well-nourished mice, but malnourished animals failed to respond to infection in the same fashion. Malnutrition induced significant reduction of chemotactic and pro-inflammatory molecules as well as of proteins involved in nucleic acid and amino acid metabolism, indicating an impaired proliferative microenvironment. Accordingly, a significant decrease in Ki67 expression was observed, suggesting that splenocyte proliferation is compromised in malnourished animals. Together, our results show that malnutrition compromises the splenic microenvironment and alters the immune response to the parasite in malnourished individuals. SIGNIFICANCE: Protein malnutrition is recognized as an important epidemiological risk factor for developing visceral leishmaniasis (VL). Locally secreted factors present in the interstitial fluid have important roles in initiating immune responses and in regulating fluid volume during inflammation. However, the regulation of secreted factors under pathological conditions such as malnutrition and infection are widely unknown. To analyze how protein malnutrition alters secreted proteins involved in the immune response to L. infantum infection we evaluated the proteomic profile of the interstitial fluid of the spleen in malnourished BALB/c mice infected with L. infantum. Our work revealed new elements that contribute to the understanding of the immunopathological events in the spleen of malnourished animals infected with L. infantum and opens new pathways for consideration of other aspects that could improve VL treatment in malnourished individuals.
Assuntos
Proliferação de Células , Líquido Extracelular/metabolismo , Perfilação da Expressão Gênica , Leishmania infantum/metabolismo , Leishmaniose Visceral/metabolismo , Desnutrição/metabolismo , Proteômica , Baço/metabolismo , Animais , Líquido Extracelular/parasitologia , Inflamação/metabolismo , Inflamação/parasitologia , Inflamação/patologia , Leishmaniose Visceral/patologia , Masculino , Desnutrição/parasitologia , Desnutrição/patologia , Camundongos , Camundongos Endogâmicos BALB C , Baço/parasitologia , Baço/patologiaRESUMO
Detrimental effects of malnutrition on immune responses to pathogens have long been recognized and it is considered a main risk factor for various infectious diseases, including visceral leishmaniasis (VL). Thymus is a target of both malnutrition and infection, but its role in the immune response to Leishmania infantum in malnourished individuals is barely studied. Because we previously observed thymic atrophy and significant reduction in cellularity and chemokine levels in malnourished mice infected with L. infantum, we postulated that the thymic microenvironment is severely compromised in those animals. To test this, we analyzed the microarchitecture of the organ and measured the protein abundance in its interstitial space in malnourished BALB/c mice infected or not with L. infantum. Malnourished-infected animals exhibited a significant reduction of the thymic cortex:medulla ratio and altered abundance of proteins secreted in the thymic interstitial fluid. Eighty-one percent of identified proteins are secreted by exosomes and malnourished-infected mice showed significant decrease in exosomal proteins, suggesting that exosomal carrier system, and therefore intrathymic communication, is dysregulated in those animals. Malnourished-infected mice also exhibited a significant increase in the abundance of proteins involved in lipid metabolism and tricarboxylic acid cycle, suggestive of a non-proliferative microenvironment. Accordingly, flow cytometry analysis revealed decreased proliferation of single positive and double positive T cells in those animals. Together, the reduced cortical area, decreased proliferation, and altered protein abundance suggest a dysfunctional thymic microenvironment where T cell migration, proliferation, and maturation are compromised, contributing for the thymic atrophy observed in malnourished animals. All these alterations could affect the control of the local and systemic infection, resulting in an impaired response to L. infantum infection.