scholarly journals Long Term Sustained Growth of Insulin Producing Cells Using Agarose-Chitosan Coated Silver Nanocomposites

2021 ◽  
Vol 3 (1) ◽  
pp. 1-13
Author(s):  
Anasuya Ganguly ◽  
Keyword(s):  
Tissue Engineering ◽  
Insulin Secretion ◽  
Western Blotting ◽  
Extended Period ◽  
Transcript Level ◽  
Pancreatic Tissue ◽  
Isolated Population ◽  
Sustained Growth ◽  
Pancreatic Cells

Diabetes is a group of diseases characterized by high levels of blood sugar for an extended period. Despite newer and effective therapy, current treatment is riddled with fundamental challenges. To overcome the adverse effects of existing drugs, regenerative medicine has emerged as an essential treatment, for which tissue engineering may serve as a foundation for the repair of pancreatic cells secreting insulin. Different polymeric scaffolds have been explored for pancreatic tissue engineering. In the current study, a continuation of our preceding work we attempt to test the role of previously synthesized agarose-chitosan coated silver nanocomposite scaffold (AG-CHNp) for the long-term growth of pancreatic cells. Pancreatic cells were isolated from BALB/c mice and were characterized by dithizone (DTZ) staining, real time polymerase chain reaction (RT-PCR), western blotting, and flow cytometry for characteristic pancreatic markers. The isolated population of cells was grown on scaffolds and its effectiveness towards insulin secretion was studied. The isolated population was found to be positive for glucagon, PDX-1 and Pax-4, while a 200-fold change transcript level of insulin was observed. The cells upon seeding on the scaffolds exhibited sustained growth and insulin secretion as confirmed by western blotting. Overall, the study demonstrates the suitability and application of AG-CHNp for pancreatic tissue engineering.

Local Integrin Activation in Pancreatic Cells Targets Insulin Secretion to the Vasculature

2018 ◽  
Author(s):  
WannJun Gan ◽  
OanhhHoang Do ◽  
Louise Cottle ◽  
Elena Kosobrodova ◽  
Justin CooperrWhite ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Integrin Activation ◽  
Pancreatic Cells

Population fragmentation causes inadequate gene flow and increases extinction risk

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Gene Flow ◽  
Extinction Risk ◽  
Random Mating ◽  
Large Population ◽  
Isolated Population ◽  
Population Fragmentation ◽  
Single Population ◽  
Total Size ◽  
Limited Gene Flow

Most species now have fragmented distributions, often with adverse genetic consequences. The genetic impacts of population fragmentation depend critically upon gene flow among fragments and their effective sizes. Fragmentation with cessation of gene flow is highly harmful in the long term, leading to greater inbreeding, increased loss of genetic diversity, decreased likelihood of evolutionary adaptation and elevated extinction risk, when compared to a single population of the same total size. The consequences of fragmentation with limited gene flow typically lie between those for a large population with random mating and isolated population fragments with no gene flow.

scholarly journals Long-Term Cryopreservation Does Not Affect Quality of Peripheral Blood Stem Cell Grafts: A Comparative Study of Native, Short-Term and Long-Term Cryopreserved Haematopoietic Stem Cells

2021 ◽  
Vol 30 ◽  
pp. 096368972110360
Author(s):  
Daniel Lysak ◽  
Michaela Brychtová ◽  
Martin Leba ◽  
Miroslava Čedíková ◽  
Daniel Georgiev ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Statistical Significance ◽  
Extended Period ◽  
High Dose ◽  
Atp Production ◽  
Cd34 Cells ◽  
Negative Effect

Cryopreserved haematopoietic progenitor cells are used to restore autologous haematopoiesis after high dose chemotherapy. Although the cells are routinely stored for a long period, concerns remain about the maximum storage time and the possible negative effect of storage on their potency. We evaluated the effect of cryopreservation on the quality of peripheral stem cell grafts stored for a short (3 months) and a long (10 years) period and we compared it to native products.The viability of CD34+ cells remained unaffected during storage, the apoptotic cells were represented up to 10% and did not differ between groups. The clonogenic activity measured by ATP production has decreased with the length of storage (ATP/cell 1.28 nM in native vs. 0.63 in long term stored products, P < 0.05). Only borderline changes without statistical significance were detected when examining mitochondrial and aldehyde dehydrogenase metabolic activity and intracellular pH, showing their good preservation during cell storage. Our experience demonstrates that cryostorage has no major negative effect on stem cell quality and potency, and therefore autologous stem cells can be stored safely for an extended period of at least 10 years. On the other hand, long term storage for 10 years and longer may lead to mild reduction of clonogenic capacity. When a sufficient dose of stem cells is infused, these changes will not have a clinical impact. However, in products stored beyond 10 years, especially when a low number of CD34+ cells is available, the quality of stem cell graft should be verified before infusion using the appropriate potency assays.

scholarly journals Long-Term Cryostorage of Mesenchymal Stem Cell-Containing Hybrid Hydrogel Scaffolds Based on Fibrin and Collagen

Gels ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 44
Author(s):  
Marfa N. Egorikhina ◽  
Yulia P. Rubtsova ◽  
Diana Ya. Aleynik
Keyword(s):  
Tissue Engineering ◽  
Proliferative Activity ◽  
Experimental Protocol ◽  
Hydrogel Scaffold ◽  
Hybrid Hydrogel ◽  
Hydrogel Scaffolds ◽  
High Viability ◽  
Scaffold Structure ◽  
Difficult Issue

The most difficult issue when using tissue engineering products is enabling the ability to store them without losing their restorative capacity. The numbers and viability of mesenchymal stem cells encapsulated in a hydrogel scaffold after cryostorage at −80 °C (by using, individually, two kinds of cryoprotectors—Bambanker and 10% DMSO (Dimethyl sulfoxide) solution) for 3, 6, 9, and 12 months were determined, with subsequent assessment of cell proliferation after 96 h. The analysis of the cellular component was performed using fluorescence microscopy and the two fluorochromes—Hoechst 3334 and NucGreenTM Dead 488. The experimental protocol ensured the preservation of cells in the scaffold structure, retaining both high viability and proliferative activity during storage for 3 months. Longer storage of scaffolds led to their significant changes. Therefore, after 6 months, the proliferative activity of cells decreased. Cryostorage of scaffolds for 9 months led to a decrease in cells’ viability and proliferative activity. As a result of cryostorage of scaffolds for 12 months, a decrease in viability and proliferative activity of cells was observed, as well as pronounced changes in the structure of the hydrogel. The described scaffold cryostorage protocol could become the basis for the development of storage protocols for such tissue engineering products, and for helping to extend the possibilities of their clinical use while accelerating their commercialization.

scholarly journals How Do Trade-Offs and Synergies between Ecosystem Services Change in the Long Period? The Case Study of Uxin, Inner Mongolia, China

2019 ◽  
Vol 11 (21) ◽  
pp. 6041 ◽  
Author(s):  
Zhang ◽  
Li ◽  
Buyantuev ◽  
Bao ◽  
Zhang
Keyword(s):  
Ecosystem Services ◽  
Inner Mongolia ◽  
Stepwise Regression ◽  
Driving Forces ◽  
Extended Period ◽  
Trade Offs ◽  
Development And Utilization ◽  
Long Term Trends

Ecosystem services management should often expect to deal with non-linearities due to trade-offs and synergies between ecosystem services (ES). Therefore, it is important to analyze long-term trends in ES development and utilization to understand their responses to climate change and intensification of human activities. In this paper, the region of Uxin in Inner Mongolia, China, was chosen as a case study area to describe the spatial distribution and trends of 5 ES indicators. Changes in relationships between ES and driving forces of dynamics of ES relationships were analyzed for the period 1979–2016 using a stepwise regression. We found that: the magnitude and directions in ES relationships changed during this extended period; those changes are influenced by climate factors, land use change, technological progress, and population growth.

scholarly journals Pancreatic beta-cells expressing the Arg64 variant of the beta(3)-adrenergic receptor exhibit abnormal insulin secretory activity

2001 ◽  
Vol 27 (2) ◽  
pp. 133-144 ◽  
Author(s):  
R Perfetti ◽  
H Hui ◽  
K Chamie ◽  
S Binder ◽  
M Seibert ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Beta Cells ◽  
Western Blotting ◽  
Adrenergic Receptor ◽  
Pancreatic Beta Cells ◽  
Secretory Activity ◽  
Host Cells ◽  
Human Pancreas ◽  
Dependent Manner ◽  
Wild Type

The Arg64 beta(3)-adrenergic receptor (beta(3)AR) variant is associated with an earlier age of onset of diabetes and lower levels of insulin secretion in humans. The aims of this study were to investigate whether beta(3)AR is expressed by islet cells, if receptor binding affects insulin secretion and, finally, if the beta(3)AR Arg64 variant induces abnormal insulin secretory activity. Human pancreas extracts were subjected to RT-PCR, Western blotting and immunostaining analyses. DNA sequencing and Western blotting demonstrated that the beta(3)AR gene is transcribed and translated in the human pancreas; immunostaining showed that it is expressed by the islets of Langerhans. Cultured rat beta-cells responded to human beta(3)AR agonists in a dose- and time-dependent manner. Transfection of cultured rat beta-cells with the wild-type human beta(3)AR produced an increased baseline and ligand-dependent insulin secretion compared with parental cells. On the other hand, cells transfected with the Arg64 variant of the beta(3)AR secreted less insulin, both spontaneously and after exposure to human beta(3)AR agonists. Furthermore, while transfection with the wild-type beta(3)AR preserved the glucose-dependent secretion of insulin, expression of the variant receptor rendered the host cells significantly less responsive to glucose. In summary, cells express the beta(3)AR, and its activation contributes to the regulation of insulin secretion. These findings may help explain the low levels of insulin secretion in response to an i.v. glucose tolerance test observed in humans carrying the Arg64 polymorphism.

A Paradigm for Functional Tissue Engineering

2000 ◽  
Author(s):  
David L. Butler
Keyword(s):  
Tissue Engineering ◽  
Tendon Repair ◽  
National Committee ◽  
New Paradigm ◽  
Functional Tissue Engineering ◽  
Functional Tissue ◽  
Tissue Engineer ◽  
Surgical Implants ◽  
The Us

Abstract Clinicians, biologists, and engineers face difficult challenges in engineering effective, cell-based composites for repair of orthopaedic and cardiovascular tissues. Whether repairing articular cartilage, bone, or blood vessel, the demands placed on the surgical implants can threaten the long-term success of the procedure. In 1998, the US National Committee on Biomechanics addressed this problem by suggesting a new paradigm for tissue engineering called “functional tissue engineering” or FTE. FTE seeks to address several important questions. What are the biomechanical demands placed upon the normal tissue and hence the tissue engineered implant after surgery? What parameters should a tissue engineer design into the implant before surgery? And what biomechanical parameters should the tissue engineer track to determine if the resulting repair is successful? To illustrate the principles, this presentation will discuss tendon repair as a model system for functional tissue engineering.

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