Meniscal repair with additive manufacture of bioresorbable polymer: From physicochemical characterization to implantation of 3D printed poly (L-co-D, L lactide-co-trimethylene carbonate) with autologous stem cells in rabbits.

Three-dimensional (3D) structures are actually the state-of-the-art technique to create porous scaffolds for tissue engineering. Since regeneration in cartilage tissue is limited due to intrinsic cellular properties this study aims to develop and characterize three-dimensional porous scaffolds of poly (L-co-D, L lactide-co-trimethylene carbonate), PLDLA-TMC, obtained by 3D fiber deposition technique. The PLDLA-TMC terpolymer scaffolds (70:30), were obtained and characterized by scanning electron microscopy, gel permeation chromatography, differential scanning calorimetry, thermal gravimetric analysis, compression mechanical testing and study on in vitro degradation, which showed its amorphous characteristics, cylindrical geometry, and interconnected pores. The in vitro degradation study showed significant loss of mechanical properties compatible with a decrease in molar mass, accompanied by changes in morphology. The histocompatibility association of mesenchymal stem cells from rabbit's bone marrow, and PLDLA-TMC scaffolds, were evaluated in the meniscus regeneration, proving the potential of cell culture at in vivo tissue regeneration. Nine New Zealand rabbits underwent total medial meniscectomy, yielding three treatments: implantation of the seeded PLDLA-TMC scaffold, implantation of the unseeded PLDLA-TMC and negative control (defect without any implant). After 24 weeks, the results revealed the presence of fibrocartilage in the animals treated with polymer. However, the regeneration obtained with the seeded PLDLA-TMC scaffolds with mesenchymal stem cells had become intimal to mature fibrocartilaginous tissue of normal meniscus both macroscopically and histologically. This study demonstrated the effectiveness of the PLDLA-TMC scaffold in meniscus regeneration and the potential of mesenchymal stem cells in tissue engineering, without the use of growth factors. It is concluded that bioresorbable polymers represent a promising alternative for tissue regeneration.

Crosslinked Collagen-Hyaluronic Acid Scaffold Enhances Interleukin-10 Under Co-Culture of Macrophages And Adipose-Derived Stem Cells.

The skin, the human body's largest organ, possesses a protective barrier that renders it susceptible to various injuries, including burns. Following burn trauma, the inflammatory process triggers both innate and adaptive immune responses, leading to the polarization of macrophages into two distinct phenotypes: the pro-inflammatory M1 and the anti-inflammatory M2. This dual response sets the stage for wound healing and subsequent tissue regeneration. Contributing to this transition from M1 to M2 polarization are human adipose-derived stem cells (ASCs), which employ paracrine signaling and inflammation suppression to enhance the remodeling phase. ASCs, when combined with biocompatible polymers, can be integrated into functional scaffolds. This study introduces an 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-crosslinked (EDC-crosslinked) collagen-hyaluronic acid (Col-HA) scaffold assembled with ASCs, designed as a natural biomaterial device to modulate macrophage behavior in vitro under co-culture conditions. This innovation aims to improve wound healing processes. The EDC-crosslinked Col-HA scaffold favored the release of anti-inflammatory cytokines by ASCs, which indicated the M2 prevalence. In tissue engineering, a critical objective lies in the development of functional biomaterials capable of guiding specific tissue responses, notably the control of inflammatory processes. Thus, this research not only presents original findings but also points toward a promising avenue within regenerative medicine.

Electrospun Membrane Based on Poly(L-co-D,L lactic acid) and Natural Rubber Containing Copaiba Oil Designed as a Dressing with Antimicrobial Properties.

Drug delivery systems of natural antimicrobial compounds, such as copaiba oil (CO), have become relevant in the scientific community due to the recent prevalence of the public health complications related to antibiotic resistance. Electrospun devices act as an efficient drug delivery system for these bioactive compounds, reducing systemic side effects and increasing the effectiveness of the treatment. In this way, the present study aimed to evaluate the synergistic and antimicrobial effect of the direct incorporation of different concentrations of CO in a poly(L-co-D,L lactic acid) and natural rubber (NR) electrospun membrane. It was observed that CO showed bacteriostatic and antibacterial effects against S. aureus in antibiogram assays. The prevention of biofilm formation was confirmed via scanning electron microscopy. The test with crystal violet demonstrated strong bacteria inhibition in membranes with 75% CO. A decrease in hydrophilicity, observed in the swelling test, presented that the addition of CO promotes a safe environment for the recovery of injured tissue while acting as an antimicrobial agent. In this way, the study showed strong bacteriostatic effects of the CO incorporation in combination with electrospun membranes, a suitable feature desired in wound dressings in order to promote a physical barrier with prophylactic antimicrobial properties to avoid infections during tissue healing.

Thiamethoxam and picoxystrobin reduce the survival and overload the hepato-nephrocitic system of the Africanized honeybee.

Apis mellifera perform important pollination roles in agroecosystems. However, there is often intensive use of systemic pesticides in crops, which can be carried to the colony by forage bees through the collection of contaminated pollen and nectar. Inside the colony, pollen loads are stored by bees that add honey and several enzymes to this pollen. Nevertheless, intra-colonial chronic exposure could induce sublethal effects in young bees exposed to a wide range of pesticides present in these pollen loads. This study was aimed to both determine the survival rate and evaluate the sublethal effects on the hepato-nephrocitic system in response to continuous oral exposure to lower concentrations of neonicotinoid thiamethoxam (TXT) and picoxystrobin fungicide (PXT). Exposure to a single chemical and co-exposure to both pesticides were performed in newly emerged honeybee workers. A significant decrease in the bee survival rates was observed following exposure to TXT (0.001 ng a.i./µL) and PXT (0.018 ng a.i./µL), as well as following co-exposure to TXT+PXT/2. After five days of continuous exposure, TXT induced sub-lethal effects in the organs involved in the detoxification of xenobiotics, such as the fat body and pericardial cells, and it also induced a significant increase in the hemocyte number. Thus, the hepato-nephrocitic system (HNS) reached the greatest level of activity of pericardial cells as an attempt to eliminate this toxic compound from hemolymph. The HNS was activated at low levels by PXT without an increase in the hemocyte number; however, the mobilization of neutral glycoconjugates from the trophocytes of the fat body was prominent only in this group. TXT and PXT co-exposure induced intermediary morphological effects in trophocytes and pericardial cells, but oenocytes from the fat body presented with atypical cytoplasm granulation only in this group. These data showed that the realistic concentrations of these pesticides are harmful to newly emerged Africanized honeybees, indicating that intra-colonial chronic exposure drastically reduces the longevity of bees exposed to neonicotinoid insecticide (TXT) and the fungicide strobilurin (PXT) as in single and co-exposure. Additionally, the sublethal effects observed in the organs constituting the HNS suggest that the activation of this system, even during exposure to low concentrations of theses pesticides, is an attempt to maintain homeostasis of the bees. These data together are alarming because these pesticides can affect the performance of the entire colony.

Microvascular reactivity in type 1 diabetics.

OBJECTIVE: To evaluate whether differences are present in microvascular response to the schemia induced by dynamic videocapillaroscopy (VCD), through analysis of the measured capillar transverse segment area (CTSA) in patients with type 1 diabetes mellitus (T1DM). METHODS: The vascular reactivity of the CTSA was studied by VCD, using a reactive hyperemia test in 61 volunteers, being 31 healthy controls without diabetes family history (Group 1) and 30 patients with T1DM without complications (Group 2). The images were captured every two seconds, during reperfusion after one minute induced ischaemia, and they were analyzed by the program Studio Version 8 and Motic Image Plus. The pre-ischemia capillary transverse segment (basal area, BA), the maximum strain post-ischemia (maximum area, MA), and time to achieve it (MAt) were measured during reperfusion, and the increased area percentage (Ap) was estimated. RESULTS: The mean differences between groups were evaluated by the t-test. The median comparisons between the groups were studied by the Mann-Whitney test. There was no difference in BA between the groups. The Ap was significantly lower among the diabetic patients, and there was a significant increase in the Mat among the patients of Group 2 when compared to Group 1. CONCLUSIONS: These data suggest that type 1 diabetes provokes earlier endothelial dysfunction, before the onset of clinically detectable degenerative complications. The outcomes from these alterations need further studies.

Microvascular reactivity in type 1 diabetics / Reatividade microvascular em diabéticos tipo 1

OBJECTIVE: To evaluate whether differences are present in microvascular response to the schemia induced by dynamic videocapillaroscopy (VCD), through analysis of the measured capillar transverse segment area (CTSA) in patients with type 1 diabetes mellitus (T1DM). METHODS: The vascular reactivity of the CTSA was studied by VCD, using a reactive hyperemia test in 61 volunteers, being 31 healthy controls without diabetes family history (Group 1) and 30 patients with T1DM without complications (Group 2). The images were captured every two seconds, during reperfusion after one minute induced ischaemia, and they were analyzed by the program Studio Version 8 and Motic Image Plus. The pre-ischemia capillary transverse segment (basal area, BA), the maximum strain post-ischemia (maximum area, MA), and time to achieve it (MAt) were measured during reperfusion, and the increased area percentage (Ap) was estimated. RESULTS: The mean differences between groups were evaluated by the t-test. The median comparisons between the groups were studied by the Mann-Whitney test. There was no difference in BA between the groups. The Ap was significantly lower among the diabetic patients, and there was a significant increase in the Mat among the patients of Group 2 when compared to Group 1. CONCLUSIONS: These data suggest that type 1 diabetes provokes earlier endothelial dysfunction, before the onset of clinically detectable degenerative complications. The outcomes from these alterations need further studies.

OBJETIVO: Avaliar se há diferença de resposta microcirculatória à isquemia induzida pela videocapilaroscopia dinâmica (VCD), por meio da análise de medida da área do segmento transverso capilar (ASTC) em pacientes com diabetes melito tipo 1 (DMT1). MÉTODOS: A reatividade vascular do ASTC foi estudada pela VCD usando o teste de hiperemia reativa em 61 voluntários, sendo 31 controles sadios sem história familiar de diabetes (Grupo 1) e 30 pacientes com DMT1, sem complicações (Grupo 2). As imagens foram capturadas a cada dois segundos, durante a reperfusão após um minuto de isquemia induzida, e analisadas pelo programa Studio Version 8 e Motic Image Plus. O segmento transverso pré-isquemia (área basal, AB), a área máxima pós-isquemia (área máxima, AM) e o tempo para alcançá-la foram medidos durante a reperfusão, e o percentual de incremento foi estimado. RESULTADOS: As principais diferenças entre os grupos foram avaliadas pelo teste t. As médias comparativas entre os grupos foram avaliadas pelo teste Mann-Whitney. Não houve diferença na área basal entre os dois grupos. O percentual de incremento foi significativamente menor entre os pacientes diabéticos e houve um aumento significativo no ASTC entre os pacientes do Grupo 2 quando comparados com o Grupo 1. CONCLUSÕES: Os dados sugerem que o diabetes tipo 1 provoca disfunção endotelial precoce, antes mesmo de complicações degenerativas serem detectadas clinicamente. Os fatores que levam a essas alterações necessitam de estudos adicionais.