Angiogenic potential of mesenchymal stem cells derived from patients with diabetes seeded on decellularized micro fragments.

Mesenchymal stem cells (MSCs) are a potential source of angiogenic factors which may promote wound healing in poorly vascularized diabetic foot ulcers. We demonstrate that MSCs of patients with diabetic foot ulcers seeded on decellularized micro-fragments transcribe and secrete angiogenic factors in amounts comparable to MSCs derived from healthy individuals.

Creation of a vascular inducing device using mesenchymal stem cells to induce angiogenesis.

Conventional treatments of peripheral vascular disease and coronary artery disease have partial success but are still limited. Methods to deliver angiogenic factors into ischemic areas using gene, protein and cell therapies are faced with difficult issues such a delivery, effective concentration and duration of action. Tissue engineering offers the possibility of creating a functional self-contained three-dimensional (3D) unit that works as a coordinated biological pump that can secrete a whole range of angiogenic factors.

Paracrine Signaling from a Three-Dimensional Model of Bladder Carcinoma and from Normal Bladder Switch the Phenotype of Stromal Fibroblasts.

We present a three-dimensional model based on acellular scaffolds to recreate bladder carcinoma in vitro that closely describes the in vivo behavior of carcinoma cells. The integrity of the basement membrane and protein composition of the bladder scaffolds were examined by Laminin immunostaining and LC-MS/MS. Human primary bladder carcinoma cells were then grown on standard monolayer cultures and also seeded on the bladder scaffolds.

An Like Micro-Carcinoma Model.

We here present a novel micro-system which allows to reconstitute an in vivo lung carcinoma where the various constituting epithelial and/or stromal structural and/or cellular components can be incorporated at will. In contrast to various "organs on a chip" the model is based on the observation that in nature, epithelial cells are always supported by a connective tissue or stroma. The model is based on acellular micro-scaffolds of microscopic dimensions which enable seeded cells to obtain gases and nutrients through diffusion thus avoiding the need for vascularization.

Lung-Derived Microscaffolds Facilitate Diabetes Reversal after Mouse and Human Intraperitoneal Islet Transplantation.

There is a need to develop three-dimensional structures that mimic the natural islet tissue microenvironment. Endocrine micro-pancreata (EMPs) made up of acellular organ-derived micro-scaffolds seeded with human islets have been shown to express high levels of key beta-cell specific genes and secrete quantities of insulin per cell similar to freshly isolated human islets in a glucose-regulated manner for more than three months in vitro. The aim of this study was to investigate the capacity of EMPs to restore euglycemia in vivo after transplantation of mouse or human islets in chemically diabetic mice.

Frog skin cultures secrete anti-yellow fever compounds.

There is an urgent need to develop novel antimicrobial substances. Antimicrobial peptides (AMPs) are considered as promising candidates for future therapeutic use. Because of the re-emergence of the Flavivirus infection, and particularly the yellow fever virus (YFV), we have compared the antiviral activities from skin secretions of seven different frog species against YFV (strain 17D).

Beta Cells Secrete Significant and Regulated Levels of Insulin for Long Periods when Seeded onto Acellular Micro-Scaffolds.

The aim of this work is to obtain significant and regulated insulin secretion from human beta cells ex vivo. Long-term culture of human pancreatic islets and attempts at expanding human islet cells normally result in loss of beta-cell phenotype. We propose that to obtain proper ex vivo beta cell function, there is a need to develop three-dimensional structures that mimic the natural islet tissue microenvironment.

Kidney-specific microscaffolds and kidney-derived serum-free conditioned media support in vitro expansion, differentiation, and organization of human embryonic stem cells.

We report a novel method for culturing human embryonic stem cells (HES) using 300-μm-thick acellular kidney-derived microscaffolds (KMSs) that allow cells to obtain nutrients and gasses simply by diffusion, enabling the KMSs to be used readily ex vivo under defined culture conditions, without the need for vascularization/perfusion or transplantation. Standard histology and scanning electron microscopy show that HES grow and expand according to the complex structure dictated by the scaffold. We further show that the expression levels of NPHS-1, REN, AQP-1, SLC2A2, and ANPEP were 7.

Kidney derived micro-scaffolds enable HK-2 cells to develop more in-vivo like properties.

Many cell lines, despite the fact that they are easy to culture, tend to lose some of their in vivo characteristics in vitro, we therefore decided to investigate whether culturing HK-2 cells on kidney derived micro-scaffolds (KMS) could improve proximal tubule functionality to these cells. Kidney derived micro-scaffolds (KMS) have been prepared that, due to the fact that they are only 300 µm in depth, allow for transfer of gases and nutrients via diffusion whilst maintaining the kidney's intricate microstructure. Culturing HK-2 on KMS shows significant increase in expression of AQP-1, ATP1B1, SLC23A1 and SLC5A2 after 1, 2 and 3 weeks compared with HK-2 grown under standard tissue culture conditions.

Genes related to differentiation are correlated with the gene regulatory network structure.

Motivation: Many secondary messengers, receptors and transcription factors are related to cell differentiation. Their role in cell differentiation can be affected by their position in the gene regulatory network. Here, we test whether the properties of the gene regulatory network can highlight which genes and proteins are associated with cell differentiation.

Mathematical conditions for induced cell differentiation and trans-differentiation in adult cells.

We present a theoretical framework for the analysis of the effect of a fully differentiated cell population on a neighboring stem cell population in Multi-Cellular Organisms (MCOs). Such an organism is constituted by a set of different cell populations, each set of which converges to a different cycle from all possible options, of the same Boolean network. Cells communicate via a subset of the nodes called signals.

Skin micro-organs from several frog species secrete a repertoire of powerful antimicrobials in culture.

This work is an attempt to take advantage of the rich biodiversity that exists in Colombia in order to start a systematic analysis of antimicrobial substances that have emerged through amphibian evolution. For this purpose we have developed a technique to grow intact frog skin derived micro-organs (SMOs) in vitro in the absence of serum. We show that in SMOs, the skin glands remain intact and continue to secrete into the medium substances with potent antibacterial activity, for several days in culture.

Fertility preservation in girls.

Children that undergo treatment for cancer are at risk of suffering from subfertility or hormonal dysfunction due to the detrimental effects of radiotherapy and chemotherapeutic agents on the gonads. Cryopreservation of ovarian tissue prior to treatment offers the possibility of restoring gonadal function after resumption of therapy. Effective counseling and management of pediatric patients is crucial for preserving their future reproductive potential.

Biopump: Autologous skin-derived micro-organ genetically engineered to provide sustained continuous secretion of therapeutic proteins.

A novel approach for sustained production of therapeutic proteins is described, using genetic modification of intact autologous micro-organ tissue explants from the subject's own skin. The skin-derived micro-organ can be maintained viable ex vivo for extended periods and is transduced with a transgene encoding a desired therapeutic protein, resulting in protein-secreting micro-organ (biopump (BP)). The daily protein production from each BP is quantified, enabling drug dosing by subcutaneous implantation of the requisite number of BPs into the patient to provide continuous production to the circulation of a known amount of the therapeutic protein.

Organ-specific scaffolds for in vitro expansion, differentiation, and organization of primary lung cells.

In light of the increasing need for differentiated primary cells for cell therapy and the rapid dedifferentiation occurring during standard in vitro cultivation techniques, there is an urgent need for developing three-dimensional in vitro systems in which expanded cells display in vivo-like differentiated phenotypes. It is becoming clear that the natural microenvironment provides the optimal conditions for achieving this aim. To this end, we prepared natural decellularized scaffolds of microscopic dimensions that would allow appropriate diffusion of gases and nutrients to all seeded cells.

Micro-organ ovarian transplantation enables pregnancy: a case report.

A 19-year-old thalassemic woman had tissue from one of her ovaries cryopreserved prior to bone marrow transplantation, total body irradiation and sterilizing chemotherapy. As expected, premature ovarian failure resulted from this treatment. Transplantation of her thawed ovarian tissue resulted in return of menstrual cycling and the patient then underwent several IVF cycles.

An integrative quantitative model of factors influencing the course of anorexia nervosa over time.

Objective: To identify factors influencing the course of anorexia nervosa (AN) over time.

Method: Former female patients with AN (36 remitted and 24 nonremitted) and 31 healthy females responded to standardized interviews and self-rating questionnaires. Remitted patients maintained normal eating, normal weight, and regular menses for the past 12 months.

Skin-derived microorgan autotransplantation as a novel approach for therapeutic angiogenesis.

Despite promising preclinical results, transient single-factor-based therapeutic angiogenesis has shown no definitive benefits in clinical trials. The use of skin-derived microorgans (SMOs), capable of sustained expression of angiogenic factors and sustained viability with their cellular and extracellular elements, constitutes an attractive alternative. We sought to evaluate the efficacy of SMO implantation in a porcine model of chronic myocardial ischemia.

Skin-derived micro-organs induce angiogenesis in rabbits.

We have recently reported an alternative cell therapy approach to induce angiogenesis. The approach is based on small organ fragments--micro-organs (MOs)--whose geometry allows preservation of the natural epithelial/mesenchymal interactions and ensures appropriate diffusion of nutrients and gases to all cells. We have shown that lung-derived MOs, when implanted into hosts, transcribe a wide spectrum array of angiogenic factors and can induce an angiogenic response that can rescue experimentally induced ischemic regions in mice.

Epithelial-mesenchymal interactions allow for epidermal cells to display an in vivo-like phenotype in vitro.

We here report that preservation of the basic epithelial-mesenchymal interactions allows for highly complex ex vivo function of epidermal cells. The approach taken is based on the preparation of organ fragments that preserve the basic epithelial/mesenchymal interactions but also ensure appropriate diffusion of nutrients and gases to all cells. Human and mice keratinocytes in such organ fragments, remain viable, proliferate and express epidermal-specific gene products when cultured in serum-free medium without added growth factors, for several weeks in vitro.

Solid tissues can be manipulated ex vivo and used as vehicles for gene therapy.

Background: Organ fragments can be cultured for weeks in vitro if they are prepared of microscopic thickness and if the basic organ structure is preserved. Such organ fragments, which we termed micro-organs (MOs), express in culture endogenous tissue-specific gene products. We have exploited this methodology to engineer MOs ex vivo by gene transfer.

A cell-based multifactorial approach to angiogenesis.

We here propose an alternative cell therapy approach to induce angiogenesis. We prepared small organ fragments whose geometry allows preservation of the natural epithelial/mesenchymal interactions and ensures appropriate diffusion of nutrients and gases to all cells. Fragments derived from lung are shown to behave as fairly independent units, to undergo a marked upregulation of angiogenic factors and to continue to function for several weeks in vitro in serum-free media.

Development of a scaled up liver device incorporating cryo-preserved pig liver micro-organs.

Background/aims: Currently there is no effective therapy for most patients with fulminant or end stage liver disease.

Methods: Pig liver micro-organs (LMOs), which preserve liver micro-architecture and ensure a maximal 150-200mum distance from a source of nutrients and gases have been prepared and a method to cryo-preserve them has been developed. A new scaled-up extra-corporeal liver device termed aLIVE-H in which LMOs are exposed to liver-like hemodynamic conditions has also been developed.

Liver micro-organs transcribe albumin and clotting factors and increase survival of 92% hepatectomized rats.

Background/aims: Currently there is no effective non-surgical therapy for most patients with fulminant or end stage chronic liver disease.

Methods: We have prepared rat liver micro-organs (LMOs), which preserve the liver micro-architecture and ensure that no cell is more than 150 microm away from a source of nutrients and gases. The function of LMOs has been evaluated in vitro and in a new extra-corporeal liver device termed aLIVE in which LMOs are exposed to liver-like hemodynamic conditions.

Cell surface expression and secretion of heparanase markedly promote tumor angiogenesis and metastasis.

The present study emphasizes the importance of cell surface expression and secretion of heparanase (endo-beta-D-glucuronidase) in tumor angiogenesis and metastasis. For this purpose, nonmetastatic Eb mouse lymphoma cells were transfected with the predominantly intracellular human heparanase or with a readily secreted chimeric construct composed of the human enzyme and the chicken heparanase signal peptide. Eb cells overexpressing the secreted heparanase invaded a reconstituted basement membrane to a much higher extent than cells overexpressing the intracellular enzyme.