Cross-linked gelatin microspheres with continuously tunable degradation profiles for renal tissue regeneration.

Collagen and gelatin-based biomaterials are widely used in tissue engineering applications. Various methods have been reported for the cross-linking of these macromolecules for the purpose of delaying their biodegradation to prolong their in vivo residence (in tissue engineering applications) or tailoring their drug releasing capacity (when used as drug carriers). In this study, a carbodiimide-based cross-linking method, also used in the production of United States Food and Drug Administration-approved products, was employed to obtain differentially cross-linked gelatin beads.

Formulation of selected renal cells for implantation into a kidney.

Delivery of cells to organs has primarily relied on formulating the cells in a nonviscous liquid carrier. We have developed a methodology to isolate selected renal cells (SRC) that have provided functional stability to damaged kidneys in preclinical models (Kelley et al. Poster presentation at 71st scientific sessions of American diabetes association , 2011; Kelley et al.

Isolation of human cadaveric pancreatic islets for clinical transplantation.

Diabetes is a debilitating condition which can lead to chronic vascular, renal, and ophthalmic disease. Type I or Juvenile Diabetes is caused by the destruction of beta cells within the islets of Langerhans within the pancreas. The beta cells are able to maintain tight control of blood glucose levels by virtue of their ability to secrete insulin in response to small increases in blood glucose concentration.

Bioreactor design considerations for hollow organs.

There are many important considerations in the design, construction, and use of a bioreactor for growing hollow organs such as vessels, gastrointestinal tissue, esophagus, and others. The growth of new organs requires a specialized container that provides sterility and an environment conducive to cell-seeding and attachment onto a three-dimensional bioabsorbable porous scaffold, incubation, maturation, and shipping for implantation. The materials' selection, dimensions, manufacturing, testing, and use of the bioreactor are all factors that should be considered in designing a bioreactor for the development of hollow organs.

Characterization of the human smooth muscle cell secretome for regenerative medicine.

Smooth muscle cells (SMC) play a central role in maintaining the structural and functional integrity of muscle tissue. Little is known about the early in vitro events that guide the assembly of 'bioartificial tissue' (constructs) and recapitulate the key aspects of smooth muscle differentiation and development before surgical implantation. Biomimetic approaches have been proposed that enable the identification of in vitro processes which allow standardized manufacturing, thus improving both product quality and the consistency of patient outcomes.

Expansion of the human adipose-derived stromal vascular cell fraction yields a population of smooth muscle-like cells with markedly distinct phenotypic and functional properties relative to mesenchymal stem cells.

Adipose tissue contains a heterogeneous cell population composed of endothelial cells, adipocytes, smooth muscle cells (SMC), and mesenchymal progenitors and stromal cells that meet the criteria put forth by the International Society for Cellular Therapy as defining mesenchymal stem cells (MSC). In this study, we expanded the stromal vascular fraction (SVF) of human adipose tissue and characterized the resulting adherent primary cell cultures by quantitative reverse transcription-polymerase chain reaction, antigen expression, protein fingerprinting, growth kinetics, in vitro tri-lineage differentiation bioactivity, and functional responses to small molecules modulating SMC-related developmental pathways and compared the results to those obtained with functionally validated MSC cultures. SVF-derived initial cultures (P0) were expanded in a defined medium that was not optimized for MSC growth conditions, neither were recombinant cytokines or growth factors added to the media to direct differentiation.

Functional evaluation of primary renal cell/biomaterial neo-kidney augment prototypes for renal tissue engineering.

Development of a tissue-engineered neo-kidney augment (NKA) requires evaluation of defined, therapeutically relevant cell and cell/biomaterial composites (NKA constructs) for regenerative potential in mammalian kidney. Previous work identified primary renal cell populations that extended survival and improved renal function in a rodent model of chronic kidney disease (CKD). This study extends that work toward the goal of developing NKA by (i) screening in vivo inflammatory and fibrotic responses to acellular biomaterials delivered to healthy rodent renal parenchyma, (ii) evaluating the functionality of renal cell/biomaterial combinations in vitro, (iii) generating NKA constructs by combining therapeutically relevant cell populations with biocompatible biomaterial, and (iv) evaluating in vivo neokidney tissue development in response to NKA constructs delivered to healthy rodent renal parenchyma.

Microencapsulation of engineered cells to deliver sustained high circulating levels of interleukin-6 to study hepatocellular carcinoma progression.

Interlukin-6 (IL-6) is a pleitropic cytokine that plays a central role in normal and abnormal hepatic function and response. The aims of the current study were to determine the viability of using cell encapsulation technology to introduce a genetically modified xenogeneic (CHO) cell population to elevate circulating levels of rhIL-6 in a rat model and determine the effects of sustained high rhIL-6 levels on hepatocellular carcinoma (HCC) progression in vivo. An alginate matrix was combined with transfected CHO cells, selected for their ability to synthesize rhIL-6, and used to generate uniform alginate-cell beads.

Nano to the meso scale: influence on cell transplantation.

The success of organ transplantation is one of medicine's finest accomplishments. Ironically, this same success has led to a dilemma in that there are simply too few donor organs available to treat the millions of patients that would benefit from their procurement and transplantation. The answer(s) to this shortage will likely come from transplanting specific cells, i.

Combining cell therapy and nanotechnology.

Cell transplantation to treat diseases characterised by tissue and cell dysfunction, ranging from diabetes to spinal cord injury, has made great strides preclinically and towards clinical efficacy. In order to enhance clinical outcomes, research needs to continue in areas including the development of a universal cell source that can be differentiated into specific cellular phenotypes, methods to protect the transplanted allogeneic or xenogeneic cells from rejection by the host immune system, techniques to enhance cellular integration of the transplant within the host tissue, strategies for in vivo detection and monitoring of the cellular implants, and new techniques to deliver genes to cells without eliciting a host immune response. Overcoming these obstacles will be of considerable benefit, as it allows understanding, visualising and controlling cellular interactions at a submicron level.

Subcutaneous transplantation of islets into streptozocin-induced diabetic rats.

Pancreatic islet transplantation into type 1 diabetic patients is currently being performed by intraportal infusion. This method, albeit reproducible, has some disadvantages including potential development of portal hypertension, hemorrhage, and an inability to retrieve or detect the transplanted tissue. Other transplant sites have been examined in animal models including the omentum, peritoneal cavity, and the spleen.

Sertoli cells improve survival of motor neurons in SOD1 transgenic mice, a model of amyotrophic lateral sclerosis.

Cell replacement therapy has been widely suggested as a treatment for multiple diseases including motor neuron disease. A variety of donor cells have been tested for treatment including isolated preparations from bone marrow and embryonic spinal cord. Another cell source, Sertoli cells, have been successfully used in models of diabetes, Parkinson's disease and Huntington's disease.

Use of Sertoli cell transplants to provide local immunoprotection for tissue grafts.

The recent success of allogeneic islet transplantation for the treatment of type I diabetes has renewed interest in cell therapy for diseases of secretory cell dysfunction. Unfortunately, widespread clinical use of cell transplantation is limited by tissue availability and the need for long-term immunosuppresion. Testicular Sertoli cells can confer local immunoprotection for co-transplanted cells and may provide a means of overcoming the obstacles associated with cell transplantation.

Substance P augments Borrelia burgdorferi-induced prostaglandin E2 production by murine microglia.

Substance P is a ubiquitous CNS neuropeptide and has recently been demonstrated to augment immune cell function during inflammatory events. Central to the ability of substance P to modulate immune cell function is the interaction of substance P with the substance P neurokinin-1 receptor expressed by a variety of immune cells, including microglia. CNS involvement during Lyme disease can occur when Borrelia burgdorferi, the causative agent of Lyme disease, gains access to the CNS.

Transgenic Sertoli cells as a vehicle for gene therapy.

Gene therapy involves the manipulation of genetic material to replace defective or deficient proteins to restore function in disease states. These genes are introduced into cells by mechanical, chemical, and biological approaches. To date, cell-based gene therapy has been hampered by the lack of an abundant, safe, and immunologically acceptable source of tissue.

Lithography application of a novel photoresist for patterning of cells.

Photolithography is the current workhorse for the microelectronic industry. It has been used extensively for the creation of patterns on two-dimensional surfaces. Various research groups have studied the use of photolithography to pattern surfaces for the alignment of cells.

Genetically engineered Sertoli cells are able to survive allogeneic transplantation.

The immunoprotective nature of the testis has led to numerous investigations for its ability to protect cellular grafts. Sertoli cells (SCs) are at least partially responsible for this immunoprotective environment and survive allogeneic and xenogeneic transplantation. The ability of SCs to survive transplantation leads to the possibility that they could be engineered to deliver therapeutic proteins.

The testicular-derived Sertoli cell: cellular immunoscience to enable transplantation.

There is a renewed enthusiasm for the potential of cellular transplantation as a therapy for numerous clinical disorders. The revived interest is largely due to the unprecedented success of the "Edmonton protocol," which produced a 100% cure rate for type I diabetics following the transplantation of human islet allografts together with a modified immunosuppressive regimen. While these data provide a clear and unequivocal demonstration that transplantation is a viable treatment strategy, the shortage of suitable donor tissue together with the debilitating consequences of lifelong immunosuppression necessitate a concerted effort to develop novel means to enable transplantation on a widespread basis.

Long-term survival of intratesticular porcine islets in nonimmunosuppressed beagles.

Background: The testis is an immunoprivileged organ, and at 37 degrees C, the intratesticular microenvironment supports the survival of allogeneic islets. The objective of this study was to determine whether the immunoprotection afforded by the intratesticular environment is potent enough to prevent the rejection of xenogeneic porcine islets in a large-animal model.

Methods: A bilateral cryptorchid condition was surgically created in sexually mature beagle dogs.

Synthesis, characterization, and preliminary biological study of poly(3-(tert-butoxycarbonyl)-N-vinyl-2-pyrrolidone).

Poly(3-(tert-butoxycarbonyl)-N-vinyl-2-pyrrolidone) has been synthesized and characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, NMR spectroscopy, and thermal analysis. The polymer is a chemically amplified photoresist. Arrays of lines with 25 microm width and 25 microm spacing were successfully patterned with this polymer by photolithography.

Identification of a specific Sertoli cell marker, Sox9, for use in transplantation.

The immunoprivileged environment of the testes was first described in the 1930s, and the Sertoli cell was later identified as the main cell type responsible for this phenomenon. Recent work has examined the possibility of recreating this immunoprivileged environment at heterotopic sites using isolated Sertoli cells. These studies have focused on protection of pancreatic islets and neuronal cells from immune destruction in the hopes of reversing type I diabetes and Parkinson's disease.

Application of magnetic resonance microscopy to tissue engineering: a polylactide model.

Absorbable polymers are unique materials that find application as temporary scaffolds in tissue engineering. They are often extremely sensitive to histological processing and, for this reason, studying fragile, tissue-engineered constructs before implantation can be quite difficult. This research investigates the use of noninvasive imaging using magnetic resonance microscopy (MRM) as a tool to enhance the assessment of these cellular constructs.