Therapeutic Cloning and Tissue Engineering

Advancements in craniofacial prosthesis fabrication: A narrative review of holistic treatment

The treatment of craniofacial anomalies has been challenging as a result of technological shortcomings that could not provide a consistent protocol to perfectly restore patient-specific anatomy. In the past, wax-up and impression-based maneuvers were implemented to achieve this clinical end. However, with the advent of computer-aided design and computer-aided manufacturing (CAD/CAM) technology, a rapid and cost-effective workflow in prosthetic rehabilitation has taken the place of the outdated procedures. Because the use of implants is so profound in different facets of restorative dentistry, their placement for craniofacial prosthesis retention has also been widely popular and advantageous in a variety of clinical settings. This review aims to effectively describe the well-rounded and interdisciplinary practice of craniofacial prosthesis fabrication and retention by outlining fabrication, osseointegrated implant placement for prosthesis retention, a myriad of clinical examples in the craniofacial complex, and a glimpse of the future of bioengineering principles to restore bioactivity and physiology to the previously defected tissue.

Cell behavior on the alginate-coated PLLA/PLGA scaffolds

Here, we investigated the effect of preparation temperature and alginate-coating on L929 fibroblast behavior on lyophilized microporous PLLA/PLGA (95:5, w/w) scaffolds. The lower freezing temperature used during lyophilization (-80 °C) resulted in smaller pores (around 50 μm) and higher compressive modulus (1500 kPa) than those prepared at the higher temperature (-20 °C) (pore size: 120 μm, compressive modulus: 600 kPa) (p < 0.01). Cell proliferation was significantly lower on the alginate-coated scaffolds (p < 0.05), probably due to weak cell adhesion on alginate, rapid degradation/dissolution of the alginate hydrogel (40% weight loss after 2 weeks of incubation) (p < 0.05), which resulted in loss of material and cells, and the decrease in the pH (p < 0.05), which probably resulted in decreased cell metabolic activity. Cells tended to get less round on the scaffolds prepared at -20 °C, which had lower compressive modulus and larger pores, and upon coating with alginate, which resulted in a hydrophilic surface that had lower stiffness. When the scaffolds had closer stiffness to the cells, the cells tended to get more branched. The most branched morphology of the fibroblasts was obtained in the presence of alginate, a natural polymer having a similar stiffness with that of the L929 fibroblasts (4 kPa).

Isolation and Culture of Embryonic Stem Cells, Mesenchymal Stem Cells, and Dendritic Cells from Humans and Mice

Stem cells are cells capable of proliferation, self-renewal, and differentiation into specific phenotypes. They are an essential part of tissue engineering, which is used in regenerative medicine in case of degenerative diseases. In this chapter, we describe the methods of isolating and culturing various types of stem cells, like human embryonic stem cells (hESCs), human umbilical cord derived mesenchymal stem cells (hUC-MSCs), murine bone marrow derived mesenchymal stem cells (mBM-MSCs), murine adipose tissue derived mesenchymal stem cells (mAD-MSCs), and murine bone marrow derived dendritic cells (mBMDCs). All these cell types can be used in tissue engineering techniques.

Cell Therapy for Stress Urinary Incontinence

Urinary incontinence (UI) is the involuntary loss of urine and is a common condition in middle-aged and elderly women and men. Stress urinary incontinence (SUI) is caused by leakage of urine when coughing, sneezing, laughing, lifting, and exercise, even standing leads to increased intra-abdominal pressure. Other types of UI also exist such as urge incontinence (also called overactive bladder), which is a strong and unexpected sudden urge to urinate, mixed forms of UI that result in symptoms of both urge and stress incontinence, and functional incontinence caused by reduced mobility, cognitive impairment, or neuromuscular limitations that impair mobility or dexterity. However, for many SUI patients, there is significant loss of urethral sphincter muscle due to degeneration of tissue, the strain and trauma of pregnancy and childbirth, or injury acquired during surgery. Hence, for individuals with SUI, a cell-based therapeutic approach to regenerate the sphincter muscle offers the advantage of treating the cause rather than the symptoms. We discuss current clinically relevant cell therapy approaches for regeneration of the external urethral sphincter (striated muscle), internal urethral sphincter (smooth muscle), the neuromuscular synapse, and blood supply. The use of mesenchymal stromal/stem cells is a major step in the right direction, but they may not be enough for regeneration of all components of the urethral sphincter. Inclusion of other cell types or biomaterials may also be necessary to enhance integration and survival of the transplanted cells.

Evaluating the biodegradability of Gelatin/Siloxane/Hydroxyapatite (GS-Hyd) complex in vivo and its ability for adhesion and proliferation of rat bone marrow mesenchymal stem cells

Recent studies have shown that the use of biomaterials and new biodegradable scaffolds for repair or regeneration of damaged tissues is of vital importance. Scaffolds used in tissue engineering should be biodegradable materials with three-dimensional structures which guide the growth and differentiation of the cells. They also tune physical, chemical and biological properties for efficient supplying of the cells to the selected tissues and have proper porosity along with minimal toxic effects. In this manner, the study of these characteristics is a giant stride towards scaffold design. In this study, Gelatin/Siloxane/Hydroxyapatite (GS-Hyd) scaffold was synthesized and its morphology, in vivo biodegradability, cytotoxic effects and ability for cell adhesion were investigated using mesenchymal stem cells (MSCs). The cells were treated with different volumes of the scaffold suspension for evaluation of its cytotoxic effects. The MSCs were also seeded on scaffolds and cultured for 2 weeks to evaluate the ability of the scaffold in promoting of cell adhesion and growth. To check the biodegradability of the scaffold in vivo, scaffolds were placed in the rat body for 21 days in three different positions of thigh muscle, testicle, and liver and they were analyzed by scanning electron microscopy (SEM) and weight changes. According to the results of the viability of this study, no cytotoxic effects of GS-Hyd scaffold was found on the cells and MSCs could adhere on the scaffold with expanding their elongations and forming colonies. The rate of degradation as assessed by weight loss was significant within each group along with significant differences between different tissues at the same time point. SEM micrographs also indicated the obvious morphological changes on the surface of the particles and diameter of the pores through different stages of implantation. The greatest amount of degradation happened to the scaffold particles implanted into the muscle, followed by testicle and liver, respectively.

Ex vivo-expanded bone marrow stem cells home to the liver and ameliorate functional recovery in a mouse model of acute hepatic injury

BACKGROUND

Stem cell transplantation provides a theoretical approach for liver regeneration medicine; it may promote liver regeneration and self-repair. However, the transplantation of bone marrow-mesenchymal stem cells expanded ex vivo as a therapy for liver disease has rarely been investigated. This study aimed to explore whether bone marrow stem cells expanded ex vivo home to the liver and foster hepatic recovery after CCl4 injury.

METHODS

Bone marrow cells from BALB/c mice were expanded ex vivo by multiple-passage cultivation, characterized by cytoflow immunofluorescence, and pre-labeled with PKH26 before intravenous infusion into animals treated with CCl4. The integration of bone marrow cells into the liver was examined microscopically, and plasma hepatic enzymes were determined biochemically.

RESULTS

Cultured bone marrow cells exhibited antigenic profiles comparable to those of primary medullary stem cells. Double immunofluorescence showed colocalization of these cells with proliferative activity and albumin expression in the liver of CCl4-treated mice. Densitometry showed increased in situ cell proliferation (50+/-14 vs 20+/-3 cells/high-power field, P<0.05) and albumin expression (149+/-25 vs 20+/-5 cells/high-power field, P<0.05) in the liver, as well as reduced serum aminotransferase levels (P<0.05) and better survival rates (P<0.05) in animals receiving cultured bone marrow cells relative to controls.

CONCLUSIONS

Ex vivo-expanded bone marrow cells are capable of relocating to and proliferating in the chemically-injured liver. Transplantation of these pluripotent stem cells appears to improve serum indices of liver function and survival rate in mice after CCl4-induced hepatic damage.

Regrow or repair: potential regenerative therapies for the kidney

Regenerative medicine is being heralded in a similar way as gene therapy was some 15 yr ago. It is an area of intense excitement and potential, as well as myth and disinformation. However, with the increasing rate of end-stage renal failure and limited alternatives for its treatment, we must begin to investigate seriously potential regenerative approaches for the kidney. This review defines which regenerative options there might be for renal disease, summarizes the progress that has been made to date, and investigates some of the unique obstacles to such treatments that the kidney presents. The options discussed include in situ organ repair via bone marrow recruitment or dedifferentiation; ex vivo stem cell therapies, including both autologous and nonautologous options; and bioengineering approaches for the creation of a replacement organ.

In situ stem cell therapy: novel targets, familiar challenges

Tissue engineering approaches for expanding, differentiating and engrafting embryonic or adult stem cells have significant potential for tissue repair but harnessing endogenous stem cell populations offers numerous advantages over these approaches. There has been rapid basic biological progress in the identification of stem cell niches throughout the body and the molecular factors that regulate their function. These niches represent novel therapeutic targets and efforts to use them involve the familiar challenges of delivering molecular medicines in vivo. Here we review recent progress in the use of genes, proteins and small molecules for in situ stem cell control and manipulation, with a focus on using stem cells of the central nervous system for neuroregeneration.

Tissue Engineering in Urology: Between Basic Research and Clinical Applications

Tissue engineering follows the principles of cell and tissue culture, cloning and stem cell production, and materials science to develop biological substitutes, which could repair and maintain normal function. The biomaterials must be able to control the structure and function of engineered tissue by interacting with both transplanted and host cells. Either natural or synthetic biodegradable materials have been used as cell delivery scaffolds. The stem cell field is also advancing rapidly, opening new options for regenerative medicine. In the genitourinary system, tissue engineering has been applied experimentally for the reconstitution of pelvis, ureter, bladder, urethra, penile corpora cavernosa and testis. This literature review underlines recent advances that have occurred in tissue engineering and describes their clinical repercussions, particularly in offering novel therapies in urogenital pathology.