Interaction between organ-specific stem cells and extracellular matrix (ECM) is crucial for regeneration. We therefore, investigated novel stem cells markers in human kidney and verified the potential of human fetal kidney cells (hFKC) to repopulate decellularized porcine kidneys. Adult and fetal human kidneys were stained by immunohistochemistry for putative stem cell markers. In addition, hFKC were isolated and characterized phenotypically and by gene expression. Furthermore, whole porcine kidneys were decellularized using detergents, cut into 1 mm slices, seeded with hFKC, cultured for 14 days and characterized by histology and qPCR. We found that, decellularized porcine kidneys showed significant loss of DNA but preserved some ECM components. Human fetal kidneys including hFKC expressed stem cell markers CD133, DLK-1, EPCAM and ephrin receptor EphA6. Interestingly, EphA7 and SIX2 were markedly expressed only in fetus. Furthermore, in fetal kidneys EphA7 was co-expressed with DLK-1. Recellularized kidney pieces showed cell infiltration, growing in orchestrated fashion distributed around the scaffold. These pieces also demonstrated cells expressing CK8, CK18, DLK-1, CD133, EphA7, EphB3, PCNA, podocin and increased levels of transcriptional factors in kidney development (SIX2, EYA1, CITED1, LHX1, SALL1, DLK-1 and WT1). We conclude that decellularized porcine kidneys support the culture, proliferation of hFKC and regenerate by upregulation of transcription factors. We suggest that expanded hFKC may be the ideal cell source for whole kidney regeneration in the future. We also postulate EphA7 might be a novel stem cell marker in kidneys.

Intensive research has been performed to identify the pathological mechanisms of many pediatric neurogenetic disorders and to identify potential therapeutic targets. Although research into many pediatric neurological disorders has provided tremendous insight into the mechanisms of disease, effective treatments remain elusive. A significant impediment to progress has been a lack of thorough disease models. Transgenic/knockout animal models have been very valuable in determining the mechanisms of many neurogenetic disorders; however, these models cannot always mimic human-specific pathology and can be inadequate in representing human pathogenesis. This can be especially true for diseases of the nervous system. Alternatively, human patient-derived nervous tissue can be dangerous to acquire and difficult to propagate. The development of patient-derived induced pluripotent stem cells (IPSCs) has given researchers a fresh means of modeling these disorders with renewable human cells that can be used to generate neurons and glia. IPSCs are somatic cells that are reprogrammed back to a pluripotent stage, which can provide an unlimited source of human cells possessing patient-specific genetic mutations. Their potential to be differentiated into any cell type enables them to be a flexible platform to investigate neurogenetic disease. Of course, efficient methods for differentiating IPSCs into homogeneous populations of somatic cells must be established to provide the “disease-in-a-dish” systems. We will discuss the current methods for generating IPSC-derived neural cells to model pediatric neurogenetic disorders, as well as provide examples of the disorders that have been studied that include several neurodevelopmental and neurodegenerative disorders (Rett syndrome, spinal muscular atrophy, hereditary spastic paraplegias, and leukodystrophies). In addition, we provide examples on how patient-specific neural cells can be used in therapeutic development with high-throughput drug screening platforms or with correction via genome editing.

Regenerative medicine employs stem cells to repair or to restore the function of damaged tissues. Major sources of stem cells are embryonic as well as adult tissues; however, adult stem cells are preferred for cell based regenerative therapies. Mesenchymal stem cells (MSCs) are a type of adult stem cells and they hold great promise for regenerative therapeutics. Beside other sources adipose tissue, bone marrow and cord tissue are common sources of MSCs. Significant biological differences may exist in MSCs derived from different sources due to which cells from some sources may be favoured over others for clinical use. MSC origin may be an important consideration to determine biological activity and potential use in regenerative medicine. Therefore, it is important to consider the biological characteristics of MSCs isolated from these sources. The current study briefly discusses essential characteristics (such as isolation procedures, identification, proliferative capacity and differentiation potential) of MSCs derived from umbilical cord tissue, adipose tissue and bone marrow.

Brown adipose tissue (BAT) is considered a potential tool for the treatment of obesity and type 2 diabetes due to its ability to uncouple oxidative phosphorylation and stimulate non-shivering thermogenesis that utilizes glucose and lipids as its source of energy. Previous results from our lab demonstrated that co-expression of HB-EGF and ADAM 12S resulted in lipid accumulation and a BAT-like phenotype, including up-regulation of BAT genes, down-regulation of genes involved in formation of white adipose tissues, and increased mitochondrial staining in three cell lines including mouse fibroblasts, human epidermoid carcinoma cells, and human preadipocytes. Furthermore, qRT-PCR results demonstrated up-regulation of cellular reprogramming factors such as KLF4, KLF3, and FGF-2 and down-regulation of LMNA, a marker gene involved in differentiation, in the BAT-like reprogrammed cells. This study substantiates these finding using immunohistochemical analysis of reprogrammed BAT-like cells that demonstrate increased immunofluorescent detection of FGF-2, KLF3, and PGC-1α and decreased immunofluorescence for C/EBPα. Supportive evidence of cellular reprogramming involves the use of a stem-cell transcription factor RT-profiler array that results in enhanced expression of HOXA10 (3.04-fold) and HOXC5 (6.46-fold). In order to demonstrate that HB-EGF/ADAM 12S reprogrammed BAT-like cells function as BAT, oxygen consumption and extracellular acidification rates were measured using a Seahorse XFe24 Analyzer with and without catecholamine exposure followed by FCCP + Oligomycin exposure. HB-EGF/ADAM 12S reprogrammed BAT-like cells demonstrate a significant metabolic increase compared to MLC, HB-EGF, ADAM 12S. HB-EGF/ADAM12S reprogrammed BAT-like cells exhibit a metabolic profile similar to 3T3-L1 induced BAT cells. Collectively, these results demonstrate that HB-EGF/ADAM 12S co-expression stimulates cellular reprogramming into metabolically active BAT and may be a putative therapeutic tool to combat obesity and type 2 diabetes.

The discovery of induced pluripotent stem cells (iPSC) 12 years ago has fostered the development of innovative patient-derived <em>in vitro</em> models for better understanding of disease mechanisms. This is particularly relevant to neurodegenerative diseases, where availability of live human brain tissue for research is limited and post-mortem interval changes influence readouts from autopsy-derived human tissue. Hundreds of iPSC lines have now been prepared and banked, thanks to several large scale initiatives and cell banks. Patient- or engineered iPSC-derived neural models are now being used to recapitulate cellular and molecular aspects of a variety of neurodegenerative diseases, including early and pre-clinical disease stages. The broad relevance of these models derives from the availability of a variety of differentiation protocols to generate disease-specific cell types and the manipulation to either introduce or correct disease-relevant genetic modifications. Moreover, the use of chemical and physical three-dimensional (3D) matrices improves control over the extracellular environment and cellular organization of the models. These iPSC-derived neural models can be utilised to identify target proteins and, importantly, provide high-throughput screening for drug discovery. Choosing Alzheimer’s disease (AD) as an example, this review describes 3D iPSC-derived neural models and their advantages and limitations. There is now a requirement to fully characterise and validate these 3D iPSC-derived neural models as a viable research tool that is capable of complementing animal models of neurodegeneration and live human brain tissue. With further optimization of differentiation, maturation and aging protocols, as well as the 3D cellular organisation and extracellular matrix to recapitulate more closely, the molecular extracellular-environment of the human brain, 3D iPSC-derived models have the potential to deliver new knowledge, enable discovery of novel disease mechanisms and identify new therapeutic targets for neurodegenerative diseases.

Parkinson’s disease, type 1 diabetes, and coronary artery disease are some of the few difficult diseases to control. As a result, there has been pressure in the scientific community to develop new technologies and techniques that can treat, or ultimately cure these life-threatening diseases. One such scientific advancement in bridging the gap is the use of stem cell therapy. In recent years, stem cell therapy has gained the spotlight in becoming a possible intervention for combating chronic diseases due to their unique ability to differentiate into almost any cell line. More precisely, embryonic stem cell therapy may hold the potential for becoming the ideal treatment for a multitude of diseases as embryonic stem cells are not limited in their ability to differentiate like their counterpart adult stem cells. Although there has been controversy around the usage of embryonic stem cells, there has been found a great deal of potential within the usage of these cells to treat a multitude of life-threatening diseases. In this article, we will break down the categories of diseases in which embryonic stem cell therapy can be applied into: autoimmune, neurological, and cardiovascular with three diseases relating to each category. Our aim is to provide a comprehensive review on the advantages of embryonic stem cells (ESCs) that can solve current obstacles and push advances towards stem cell therapies in the field for the most common diseases.

The molecular interactions and regulations are dynamically changed in stem cells and reprogramming. This review article mainly focuses on the networks of molecules and epigenetic regulations including microRNA. The stem cells have molecular networks related to the stemness and the reprogramming of differentiated cells include the signaling networks consist of the transcriptional and post-transcriptional regulation of the genes and the protein modification. The gene expression is regulated by the binding of microRNAs towards the regulating regions of the coding genes. The molecular network pathways in stem cells include Wnt/β-catenin signaling and MAPK signaling, Shh signaling and Hippo signaling pathway. The epigenetic regulation of the genes included in the signaling pathways related to stem cells is mediated by the transcription factors and microRNAs consist of 18–25 nucleotides. Molecular interactions of the signaling proteins in stem cells is at least three factors including the quantity of the molecules partly regulated by the gene transcription and protein synthesis, the modification of the proteins such as phosphorylation, and localization of the molecules. In the epigenetic regulation level, the methylation and acetylation of genomes are critical for the regulation of the transcription. The binding sites and the combination of microRNAs, and regulated genes related to the stem cells and reprogramming are discussed in this review.

Stem cell paracrine factors are beneficial in myocardial infarction (MI) treatment. However, specific stem cell factor effects on myocardial cytokines and their molecular pathways have not been precisely identified. We treated 44 rats with MIs with intramyocardial Isolyte or 4 × 106 human umbilical cord blood mononuclear cells (hUCBC) without immune suppression. We measured infarct sizes and myocardial cytokines. We then stressed isolated myocytes with H2O2 to simulate MIs in the absence and presence of paracrine factors from hypoxic hUCBC. We measured myocyte Akt protein kinase, which causes survival, and JNK and p38 protein kinases, which cause myocyte death. In Isolyte treated MIs, TNF-α increased from 6.1% to 51.3%, MCP increased from 5.6% to 39.8%, MIP increased from 8.1% to 25.9%, and IL-1 increased from 7.1% to 20.0%. In hUCBC treated MIs, inflammatory cytokines did not change and there was no hUCBC rejection. MI sizes averaged 30% in Isolyte treated rats and 10% in hUCBC treated rats (p 60% (all p 100% (all p < 0.01 vs. myocytes with H2O2) The Akt inhibitor API prevented hUCBC paracrine factor effects on myocytes. Addition of the JNK inhibitor SP600125 or p38 inhibitor SB203580 to myocytes with H2O2 plus hUCBC factors increased myocyte viability. We conclude that hUCBC secrete growth factors and anti-inflammatory cytokines that increase myocyte Akt activation and myocyte survival and decrease myocyte JNK, p38 and myocyte death in MIs.

Three-dimensional (3D) bioprinting is an evolving technique that is expected to revolutionize the field of regenerative medicine. Since the organ donation does not meet the demands for transplantable organs, it is important to think of another solution, which may and most likely will be provided by the technology of 3D bioprinting. However, even smaller parts of the printed renal tissue may be of help, e.g. in developing better drugs. Some simple tissues such as cartilage have been printed with success, but a lot of work is still required to successfully 3D bioprint complex organs such as the kidneys. However, few obstacles still persist such as the vascularization and the size of the printed organ. Nevertheless, many pieces of the puzzle are already available and it is just a matter of time to connect them together and 3D bioprint the kidneys. The 3D bioprinting technology provides the precision and fast speed required for generating organs. In this review, we describe the recent developments in the field of developmental biology concerning the kidneys; characterize the bioinks available for printing and suitable for kidney printing; present the existing printers and possible printing strategies. Moreover, we identify the most difficult challenges in printing of the kidneys and propose a solution, which may lead to successful bioprinting of the kidney.

This review paper endeavors to provide insights into the emergence of 3D bioprinting as an alternative to longstanding tissue fabrication techniques primarily through an overview of recent advances in bioprinting vascularized tissues. Bioprinting has promise in resolving many issues that persist within tissue engineering including: insufficient perfusion of nutrients to tissue constructs, high rates of cell necrosis, and lack of cell proliferation and proper differentiation. These issues stem from a lack of proper angiogenesis, a primary challenge that remains to be overcome in tissue engineering. This review will discuss emerging 3D bioprinting techniques (such as inkjet printing, extrusion printing, and stereolithography, among others) that have been specially adapted to enhance and improve the vascularization process. Compatible bioinks are also discussed as they are vital to the 3D bioprinting process by allowing for the building of matrices that encourage vasculature to develop, survive, and prosper under physiological flow rates. Currently, these 3D bioprinting techniques have succeeded in increasing the long-term viability of thick tissues, generated luminal structures needed for vascularization, and allowed for differentiation factors to reach cells deep within thick constructs (~1 cm). While great progress has been made, 3D bioprinting continues to have deficits in high-resolution printing, viability at prolonged time scales and larger thicknesses required for organ transplantation, and the mechanical stability needed for long-term organ functioning. Nonetheless, the recent developments in the vascularization of tissues through bioprinting techniques are paving the way for lab-grown tissues and organs, which could have uses in transplants, in vitro drug testing, and enhancing the current knowledge of organ function.