Evaluation of biological integration and inflammatory response to blood vessels produced by tissue engineering: experimental model in rabbit

The cardiovascular disease is the main cause of mortality in the western population and the Peripheral Arterial Disease (PAD) evolves, in large proportion, to the amputation of the affected limb. This study aimed to synthesize blood vessels using scaffolds of rabbit’s Inferior Vena Cava (IVC) and test its interaction with the receiver tissue and test inflammatory responses. Methods: The IVC were obtained from 8 rabbits to decellularization or in natura veins. The descellularized veins (DV) were obtained through protocols of decellularization established previously, using sodium dodecyl sulfate 1% (SDS) and mechanical agitation for 2 hours.12 animals were used to the experiment in vivo (3 animals in each group), being the product implanted in the interescapular dorsal area of each animal. The established groups are: Group 1- in natura allogeneic vein; Group 2- DV-SDS no cells added; Group 3- DV- SDS with 1x105 adipose tissue allogeneic Mesenchymal Stem Cells (MSC) added; Group 4- DV-SDS + autologous MSC. The (MSC) of the autologous receptors were collected 21 days before the implant and expanded in vitro. The explants were analyzed by histomorphological/immunohistochemistry and the peripheral blood was collected in the pre operatory in 1d, 7d, 14d, 30d and 60 day post operatory to dose the inflammatory and anti-inflammatory interleukins. Results: IL-10 and PDGF levels were significantly higher in group 4, which also showed neovascularization and large endothelial reconstruction. We may conclude the existence of an inflammatory response to the use of allogeneic grafts, which is lower when associated with autologous MSC

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Deciphering Key microRNA Regulated Pathways in Tissue-Engineered Blood Vessels: Implications for Vascular Scaffold Production

MicroRNAs (miRNAs) are non-coding RNAs involved in the regulation of gene expression associated with cell differentiation, proliferation, adhesion, and important biological functions such as inflammation. miRNAs play roles associated with the pathogenesis of chronic degenerative disorders including cardiovascular diseases. Understanding the influence of miRNAs and their target genes can effectively streamline the identification of key biologically active pathways that are important in the development of vascular grafts through the tissue engineering of blood vessels. To determine miRNA expression levels and identify miRNA target genes and pathways with biological roles in scaffolds that have been repopulated with adipose-derived stem cells (ASCs) generated through tissue engineering for the construction of blood vessels. miRNA quantification assays were performed in triplicate to determine miRNA expression in a total of 20 samples: five controls (natural inferior vena cava), five scaffolds recellularized with ASCs and differentiated into the endothelium (luminal layer), five samples of complete scaffolds seeded with ASCs differentiated into the endothelium (luminal layer) and smooth muscle (extraluminal layer), and five samples of ASC without cell differentiation. Several differentially expressed miRNAs were identified and predicted to modulate target genes with roles in key pathways associated with angiogenesis, vascular system control, and endothelial and smooth muscle regulation, including migration, proliferation, and growth. These findings underscore the involvement of these pathways in the regulatory mechanisms that are essential for vascular scaffold production through tissue engineering. Our research contributes to the knowledge of miRNA-regulated mechanisms, which may impact the design of vascular substitutes, and provide valuable insights for enhancing clinical practice. The molecular pathways regulated by miRNAs in tissue engineering of blood vessels (TEBV) allowed us to elucidate the main phenomena involved in cellular differentiation to constitute a blood vessel, with the main pathways being essential for angiogenesis, cellular differentiation, and differentiation into vascular smooth muscle

Evaluation of Biointegration and Inflammatory Response to Blood Vessels Produced by Tissue Engineering—Experimental Model in Rabbits

Peripheral arterial disease (PAD) is the main cause of mortality in the western population and requires surgical intervention with the use of vascular substitutes, such as autologous veins or Dacron or PTFE prostheses. When this is not possible, it progresses to limb amputation. For cases where there is no autologous vascular substitute, tissue engineering with the production of neovessels may be a promising option. Previous experimental studies have shown in vitro that rabbit vena cava can be decellularized and serve as a scaffold for receiving mesenchymal stem cells (MSC), with subsequent differentiation into endothelial cells. The current study aimed to evaluate the behavior of a 3D product structure based on decellularized rabbit inferior vena cava (IVC) scaffolds seeded with adipose-tissue-derived stem cells (ASCs) and implanted in rabbits dorsally subcutaneously. We evaluated the induction of the inflammatory response in the animal. We found that stem cells were positive in reducing the inflammatory response induced by the decellularized scaffolds

Urinary Bladder Patch Made with Decellularized Vein Scaffold Seeded with Adipose-Derived Mesenchymal Stem Cells: Model in Rabbits

Background: To evaluate tissue regeneration of the urinary bladder after the implantation of a decellularized vein sown with autologous adipose-derived mesenchymal stem cells (ASC) on luminal surfaces. Methods: New Zealand rabbits (n = 10) were distributed in two groups: Group Bioscaffold alone (G1)-decellularized vena cava (1 cm2) was implanted, and Group Bioscaffold plus ACSs (G2)-decellularized vena cava (1 cm2) containing ASCs were implanted. ASCs were expanded, characterized, and maintained for one week in culture with a decellularized vein scaffold. The implants were performed under general anesthesia using a continuous suture pattern. Afterward, 21 d (day) specimens were collected and analyzed by hematoxylin and eosin (HE) histology and scanning electron microscopy (SEM). Results: The integrity of the urinary bladder was maintained in both groups. A superior regenerative process was observed in the G2 group, compared to the G1 group. We observed a greater urothelial epithelialization and maturity of the mucosa and submucosa fibroblasts. Furthermore, SEM demonstrated a notable amount of urothelial villus in the G2 group. Conclusion: Decellularized vena cava scaffolds were able to maintain the integrity of the urinary bladder in the proposed model. In addition, ASCs accelerated the regenerative process development, observed primarily by the new urothelial epithelization and the maturity of mucosa and submucosa fibroblasts