Mesenchymal stem/stromal cells have unique properties favorable to their use in clinical practice and have been studied for cardiac repair. However, these cells are larger than coronary microvessels ...and there is controversy about the risk of embolization and microinfarctions, which could jeopardize the safety and efficacy of intracoronary route for their delivery. The index of microcirculatory resistance (IMR) is an invasive method for quantitatively assessing the coronary microcirculation status.
To examine heart microcirculation after intracoronary injection of mesenchymal stem/stromal cells with the index of microcirculatory resistance.
Healthy swine were randomized to receive by intracoronary route either 30x106 MSC or the same solution with no cells (1% human albumin/PBS) (placebo). Blinded operators took coronary pressure and flow measurements, prior to intracoronary infusion and at 5 and 30 minutes post-delivery. Coronary flow reserve (CFR) and the IMR were compared between groups.
CFR and IMR were done with a variance within the 3 transit time measurements of 6% at rest and 11% at maximal hyperemia. After intracoronary infusion there were no significant differences in CFR. The IMR was significantly higher in MSC-injected animals (at 30 minutes, 14.2U vs. 8.8U, p = 0.02) and intragroup analysis showed a significant increase of 112% from baseline to 30 minutes after cell infusion, although no electrocardiographic changes or clinical deterioration were noted.
Overall, this study provides definitive evidence of microcirculatory disruption upon intracoronary administration of mesenchymal stem/stromal cells, in a large animal model closely resembling human cardiac physiology, function and anatomy.
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Several processing technologies and engineering strategies have been combined to create scaffolds with superior performance for efficient tissue regeneration. Cartilage tissue is a ...good example of that, presenting limited self-healing capacity together with a high elasticity and load-bearing properties. In this work, novel porous silk fibroin (SF) scaffolds derived from horseradish peroxidase (HRP)-mediated crosslinking of highly concentrated aqueous SF solution (16 wt%) in combination with salt-leaching and freeze-drying methodologies were developed for articular cartilage tissue engineering (TE) applications. The HRP-crosslinked SF scaffolds presented high porosity (89.3 ± 0.6%), wide pore distribution and high interconnectivity (95.9 ± 0.8%). Moreover, a large swelling capacity and favorable degradation rate were observed up to 30 days, maintaining the porous-like structure and β-sheet conformational integrity obtained with salt-leaching and freeze-drying processing. The in vitro studies supported human adipose-derived stem cells (hASCs) adhesion, proliferation, and high glycosaminoglycans (GAGs) synthesis under chondrogenic culture conditions. Furthermore, the chondrogenic differentiation of hASCs was assessed by the expression of chondrogenic-related markers (collagen type II, Sox-9 and Aggrecan) and deposition of cartilage-specific extracellular matrix for up to 28 days. The cartilage engineered constructs also presented structural integrity as their mechanical properties were improved after chondrogenic culturing. Subcutaneous implantation of the scaffolds in CD-1 mice demonstrated no necrosis or calcification, and deeply tissue ingrowth. Collectively, the structural properties and biological performance of these porous HRP-crosslinked SF scaffolds make them promising candidates for cartilage regeneration.
In cartilage tissue engineering (TE), several processing technologies have been combined to create scaffolds for efficient tissue repair. In our study, we propose novel silk fibroin (SF) scaffolds derived from enzymatically crosslinked SF hydrogels processed by salt-leaching and freeze-drying technologies, for articular cartilage applications. Though these scaffolds, we were able to combine the elastic properties of hydrogel-based systems, with the stability, resilience and controlled porosity of scaffolds processed via salt-leaching and freeze-drying technologies. SF protein has been extensively explored for TE applications, as a result of its mechanical strength, elasticity, biocompatibility, and biodegradability. Thus, the structural, mechanical and biological performance of the proposed scaffolds potentiates their use as three-dimensional matrices for cartilage regeneration.
The many clinical trials currently in progress will likely lead to the widespread use of stem cell‐based therapies for an extensive variety of diseases, either in autologous or allogeneic settings. ...With the current pace of progress, in a few years' time, the field of stem cell‐based therapy should be able to respond to the market demand for safe, robust and clinically efficient stem cell‐based therapeutics. Due to the limited number of stem cells that can be obtained from a single donor, one of the major challenges on the roadmap for regulatory approval of such medicinal products is the expansion of stem cells using Good Manufacturing Practices (GMP)‐compliant culture systems. In fact, manufacturing costs, which include production and quality control procedures, may be the main hurdle for developing cost‐effective stem cell therapies. Bioreactors provide a viable alternative to the traditional static culture systems in that bioreactors provide the required scalability, incorporate monitoring and control tools, and possess the operational flexibility to be adapted to the differing requirements imposed by various clinical applications. Bioreactor systems face a number of issues when incorporated into stem cell expansion protocols, both during development at the research level and when bioreactors are used in on‐going clinical trials. This review provides an overview of the issues that must be confronted during the development of GMP‐compliant bioreactors systems used to support the various clinical applications employing stem cells.
With the current pace of progress, in a few years, stem cell‐based therapy should be able to respond to the market demand for safe, robust and clinically efficient stem cell‐based therapeutics. Bioreactors provide a viable alternative to the traditional static culture systems in that they provide the required scalability, monitoring and control tools, as well as the operational flexibility to be adapted to the different requirements of various clinical applications.
Background Umbilical cord blood (UCB) is a clinically relevant alternative source of hematopoietic stem/progenitor cells (HSPC). To overcome the low cell number per UCB unit, ex vivo expansion of UCB ...HSPC in co-culture with mesenchymal stromal cells (MSC) has been established. Bone marrow (BM)-derived MSC have been the standard choice, but the use of MSC from alternative sources, less invasive and discardable, could ease clinical translation of an expanded CD34.sup.+ cell product. Here, we compare the capacity of BM-, umbilical cord matrix (UCM)-, and adipose tissue (AT)-derived MSC, expanded with/without xenogeneic components, to expand/maintain UCB CD34.sup.+-enriched cells ex vivo. Methods UCB CD34.sup.+-enriched cells were isolated from cryopreserved mononuclear cells and cultured for 7 days over an established feeder layer (FL) of BM-, UCM-, or AT-derived MSC, previously expanded using fetal bovine serum (FBS) or fibrinogen-depleted human platelet lysate (HPL) supplemented medium. UCB cells were cultured in serum-free medium supplemented with SCF/TPO/FLT3-L/bFGF. Fold increase in total nucleated cells (TNC) as well as immunophenotype and clonogenic potential (cobblestone area-forming cells and colony-forming unit assays) of the expanded hematopoietic cells were assessed. Results MSC from all sources effectively supported UCB HSPC expansion/maintenance ex vivo, with expansion factors (in TNC) superior to 50x, 70x, and 80x in UCM-, BM-, and AT-derived MSC co-cultures, respectively. Specifically, AT-derived MSC co-culture resulted in expanded cells with similar phenotypic profile compared to BM-derived MSC, but resulting in higher total cell numbers. Importantly, a subpopulation of more primitive cells (CD34.sup.+CD90.sup.+) was maintained in all co-cultures. In addition, the presence of a MSC FL was essential to maintain and expand a subpopulation of progenitor T cells (CD34.sup.+CD7.sup.+). The use of HPL to expand MSC prior to co-culture establishment did not influence the expansion potential of UCB cells. Conclusions AT represents a promising alternative to BM as a source of MSC for co-culture protocols to expand/maintain HSPC ex vivo. On the other hand, UCM-derived MSC demonstrated inferior hematopoietic supportive capacity compared to MSC from adult tissues. Despite HPL being considered an alternative to FBS for clinical-scale manufacturing of MSC, further studies are needed to determine its impact on the hematopoietic supportive capacity of these cells. Keywords: Umbilical cord blood, Human hematopoietic stem/progenitor cells, Mesenchymal stromal cells, Bone marrow, Adipose tissue, Umbilical cord matrix, Ex vivo expansion
The development of bioactive and cell-responsive materials has fastened the field of bone tissue engineering. Gellan gum (GG) spongy-like hydrogels present high attractive properties for the tissue ...engineering field, especially due to their wide microarchitecture and tunable mechanical properties, as well as their ability to entrap the responsive cells. Lactoferrin (Lf) and Hydroxyapatite (HAp) are bioactive factors that are known to potentiate faster bone regeneration. Thus, we developed an advanced three-dimensional (3D) biomaterial by integrating these bioactive factors within GG spongy-like hydrogels. Lf-HAp spongy-like hydrogels were characterized in terms of microstructure, water uptake, degradation, and concomitant release of Lf along the time. Human adipose-derived stem cells (hASCs) were seeded and the capacity of these materials to support hASCs in culture for 21 days was assessed. Lf addition within GG spongy-like hydrogels did not change the main features of GG spongy-like hydrogels in terms of porosity, pore size, degradation, and water uptake commitment. Nevertheless, HAp addition promoted an increase of the pore wall thickness (from ~13 to 28 µm) and a decrease on porosity (from ~87% to 64%) and mean pore size (from ~12 to 20 µm), as well as on the degradability and water retention capabilities. A sustained release of Lf was observed for all the formulations up to 30 days. Cell viability assays showed that hASCs were viable during the culture period regarding cell-laden spongy-like hydrogels. Altogether, we demonstrate that GG spongy-like hydrogels containing HAp and Lf in high concentrations gathered favorable 3D bone-like microenvironment with an increased hASCs viability with the presented results.
In the present work we report a high selective synthesis of the bicyclic core present in an important angiotensin II inhibitor family of drugs (Sartans) under continuous flow conditions. The key step ...in our approach was a Suzuki–Miyaura coupling using for the first time the recently described 4-toluylboronic acid MIDA ester.
A quantitative structure-activity relationship model for Morita-Baylis-Hillman adducts with leishmanicidal activities was developed which correlates molecular orbital energy and dipole with ...percentage in the promastigote stage
Ocimum gratissimum oil is used for various medicinal, food and cosmetic applications due to its high chemical variability. Local businesses have considered the economic exploitation of this plant. A ...specimen sampled at São Luís, MA, Brazil, with thymol and derivatives oil, was subjected to seasonal and circadian study, and to antifungal and antioxidant assays. It was possible to observe that the weather conditions showed a direct influence on the oil yield and variation of its constituents, mainly oxygenated monoterpenes and monoterpene hydrocarbons, with the predominance of thymol, γ-terpinene, and p-cymene. Principal component analysis (PCA) was able to justify the oil chemical variability of the seasonal (70%) and circadian (86%) study. Oil displayed inhibition for the fungus Corynespora cassiicola at a concentration above 0.3 µL mL-1, and it showed a more significant activity by comparison to thymol. Using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay, the oil antioxidant activity was about 75% of thymol.
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