Stem Cells as a Source of Pancreatic Cells for Production of 3D Bioprinted Bionic Pancreas in the Treatment of Type 1 Diabetes.

Type 1 diabetes (T1D) is the third most common autoimmune disease which develops due to genetic and environmental risk factors. Often, intensive insulin therapy is insufficient, and patients require a pancreas or pancreatic islets transplant. However, both solutions are associated with many possible complications, including graft rejection. The best approach seems to be a donor-independent T1D treatment strategy based on human stem cells cultured in vitro and differentiated into insulin and glucagon-producing cells (ß and α cells, respectively). Both types of cells can then be incorporated into the bio-ink used for 3D printing of the bionic pancreas, which can be transplanted into T1D patients to restore glucose homeostasis. The aim of this review is to summarize current knowledge about stem cells sources and their transformation into key pancreatic cells. Last, but not least, we comment on possible solutions of post-transplant immune response triggered stem cell-derived pancreatic cells and their potential control mechanisms.

Bionic Organs: Shear Forces Reduce Pancreatic Islet and Mammalian Cell Viability during the Process of 3D Bioprinting.

BACKGROUND: 3D bioprinting is the future of constructing functional organs. Creating a bioactive scaffold with pancreatic islets presents many challenges. The aim of this paper is to assess how the 3D bioprinting process affects islet viability. METHODS: The BioX 3D printer (Cellink), 600 µm inner diameter nozzles, and 3% (w/v) alginate cell carrier solution were used with rat, porcine, and human pancreatic islets. Islets were divided into a control group (culture medium) and 6 experimental groups (each subjected to specific pressure between 15 and 100 kPa). FDA/PI staining was performed to assess the viability of islets. Analogous studies were carried out on α-cells, ß-cells, fibroblasts, and endothelial cells. RESULTS: Viability of human pancreatic islets was as follows: 92% for alginate-based control and 94%, 90%, 74%, 48%, 61%, and 59% for 15, 25, 30, 50, 75, and 100 kPa, respectively. Statistically significant differences were observed between control and 50, 75, and 100 kPa, respectively. Similar observations were made for porcine and rat islets. CONCLUSIONS: Optimal pressure during 3D bioprinting with pancreatic islets by the extrusion method should be lower than 30 kPa while using 3% (w/v) alginate as a carrier.

Novel Strategies in Artificial Organ Development: What Is the Future of Medicine?

The technology of tissue engineering is a rapidly evolving interdisciplinary field of science that elevates cell-based research from 2D cultures through organoids to whole bionic organs. 3D bioprinting and organ-on-a-chip approaches through generation of three-dimensional cultures at different scales, applied separately or combined, are widely used in basic studies, drug screening and regenerative medicine. They enable analyses of tissue-like conditions that yield much more reliable results than monolayer cell cultures. Annually, millions of animals worldwide are used for preclinical research. Therefore, the rapid assessment of drug efficacy and toxicity in the early stages of preclinical testing can significantly reduce the number of animals, bringing great ethical and financial benefits. In this review, we describe 3D bioprinting techniques and first examples of printed bionic organs. We also present the possibilities of microfluidic systems, based on the latest reports. We demonstrate the pros and cons of both technologies and indicate their use in the future of medicine.

The Influence of the Flow of Detergent and Donor Characteristics on the Extracellular Matrix Composition After Human Pancreas Decellularization.

INTRODUCTION: The extracellular matrix (ECM) consists, among others, of polysaccharides, glycosaminoglycans, and proteins. It is being increasingly used in tissue bioengineering. Obtaining ECM of the highest quality through decellularization is a big challenge because of some differences in organ structure. To deprive organs of the cellular part, chemical, enzymatic, or mechanical methods are used. After decellularization, we get a scaffold made of a variety of proteins, and it is the role of these proteins that can significantly affect the maintenance of the spatial structure and be a suitable environment for cells to rebuild a specific organ. AIM: Estimation of the detergent (Triton X-100) flow parameters and anthropometric donors' decellularization process accuracy on the final ECM composition. MATERIALS: Five human pancreata, rejected from transplantation, were used for decellularization. All organs were harvested from brain-dead donors age 13 to 60 years. METHODS: Decellularization was carried out using the flow method with Triton X-100 as an active agent. The experiment compared 5 different flow values. After decellularization, an assessment of the final DNA concentration and the protein composition was performed. Results were compared to anthropometric data of donors. In addition, a microscopic analysis was also carried out. RESULTS: The best results were obtained using a flow of 120 mL/minute. A higher detergent flow was associated with a lower concentration of residual DNA in scaffold. Analysis of the protein profile with anthropometric data has shown that LAM A2 was increasing with age and LAMA5 was decreasing. Being overweight was associated with a higher proportion of COL1 and 4 and a smaller proportion of COL6.

Type 1 diabetes: genes associated with disease development.

Type 1 diabetes (T1D) is the third most common autoimmune disease which develops due to genetic and environmental risk factors. Based on the World Health Organization (WHO) report from 2014 the number of people suffering from all types of diabetes ascended to 422 million, compared to 108 million in 1980. It was calculated that this number will double by the end of 2030. In 2015 American Diabetes Association (ADA) announced that 30.3 million Americans (that is 9.4% of the overall population) had diabetes of which only approximately 1.25 million had T1D. Nowadays, T1D represents roughly 10% of adult diabetes cases total. Multiple genetic abnormalities at different loci have been found to contribute to type 1 diabetes development. The analysis of genome-wide association studies (GWAS) of T1D has identified over 50 susceptible regions (and genes within these regions). Many of these regions are defined by single nucleotide polymorphisms (SNPs) but molecular mechanisms through which they increase or lower the risk of diabetes remain unknown. Genetic factors (in existence since birth) can be detected long before the emergence of immunological or clinical markers. Therefore, a comprehensive understanding of the multiple genetic factors underlying T1D is extremely important for further clinical trials and development of personalized medicine for diabetic patients. We present an overview of current studies and information about regions in the human genome associated with T1D. Moreover, we also put forward information about epigenetic modifications, non-coding RNAs and environmental factors involved in T1D development and onset.

Changes in Gene Expression of Selected Genes in Patients with Type 1 Diabetes and Pancreas Transplant in Peripheral Blood.

BACKGROUND: Diabetes is an autoimmunologic disease that may have a different background. The aim of our study was to show that type 1 diabetes is accompanied by changes in gene expression in peripheral blood mononuclear cells. We analyzed the genes characteristic of pancreatic islet cells and genes playing a big part in autoimmune diseases and cancer. DESIGN: The study included 21 patients and was performed to examine the expression of 9 genes. The patients were divided into 3 research groups: people with type 1 diabetes, people with diabetes after pancreas transplant, and a control group of healthy patients. To assess the level of expression, RNA material was obtained from peripheral blood collected from individuals qualified for the study. RESULTS: The results of the study showed many interesting changes in the expression level of the analyzed genes. It was demonstrated that CASR gene expression was significantly higher in transplant patients than in diabetic patients. Differences in the level of activity are also noted in genes that take part in autoimmune diseases. PROPOSAL: Profiling gene expression in peripheral blood samples may be a useful and noninvasive diagnostic tool that allows early detection of changes leading to the onset or resumption of diabetes.