Mesenchymal Stem Cell Senescence and Osteogenesis

Mesenchymal stem cells (MSCs) are stem cells with the potential ability to differentiate into various cells and the ability to self-renew and resemble fibroblasts. These cells can adhere to plastic to facilitate the culture process. MSCs can be used in research into tissue biotechnology and rejuvenation medicine. MSCs are also beneficial in recipient tissue and differentiate as a breakthrough strategy through paracrine activity. Many databases have shown MSC-based treatment can be beneficial in the reduction of osteogenesis induced by senescence. In this article, we will discuss the potential effect of MSCs in senescence cells related to osteogenesis.

Turkey Ovarian Tissue Transplantation: Effects of Surgical Technique on Graft Attachment and Immunological Status of the Grafts 6 Days Post-surgery

Background: Biobanked poultry ovaries can be revived via transplantation, into a recipient female, which upon maturity will produce donor-derived progeny. Previously, a large portion of these recipients also produced recipient-derived progeny, making them gonadal chimeras. These were potentially created when portions of the recipient’s ovary were inadvertently left behind. Completely removing the recipient ovary would solve this problem, however, leaving a portion of the recipient’s ovary may have inadvertently increased the transplant attachment rate by providing a damaged area for the transplant to attach too. To test this hypothesis in the turkey, we removed various portions (33% to 100%) of recipient ovarian tissue and determined the transplant attachment rate. Furthermore, the use of the abdominal air sac membrane as an additional anchoring point was tested. Finally, the immunological status of the grafts was evaluated by analyzing the presences of CD3 and MUM-1 (T and B cell markers), 6 days post-surgery.Results: The overall attachment rate of transplants was 91% (32/35), while the average size of the transplants was 4.2 ± 0.6 mm2. There was no difference (P > 0.05) in the attachment rates, or transplant size between groups with varying amounts of recipent tissue removed, or by using the abdominal air sac membrane as an anchor. However, all transplants were infiltrated by large numbers of T and B cells. This was shown by a high (P ≤ 0.001) percentage of CD3-positive immunostained cytoplasmic area (49.78 ± 3.90%) in transplants compared to remnant recipient tissue (0.30 ± 0.10%), as well as a high (P ≤ 0.001) percentage of MUM-1-positive immunostained nuclear area (9.85 ± 1.95%) in transplants over remnant recipient tissues (0.39 ± 0.12%).Conclusions: This study showed that neither the portion of the recipient ovary left behind nor the use of the abdominal air sac membrane affected the rate of attachment or the amount of donor tissue that attached. Thus, we recommend removing the entire recipient ovary to prevent gonadal chimeras. The high levels of lymphocytes within the grafts indicate possible tissue rejection, which could be overcome via immunosuppression with or without histocompatibility matching between donors and recipients.

Uptake, recognition and responses to peptidoglycan in the mammalian host

ABSTRACT Microbiota, and the plethora of signalling molecules that they generate, are a major driving force that underlies a striking range of inter-individual physioanatomic and behavioural consequences for the host organism. Among the bacterial effectors, one finds peptidoglycan, the major constituent of the bacterial cell surface. In the steady-state, fragments of peptidoglycan are constitutively liberated from bacterial members of the gut microbiota, cross the gut epithelial barrier and enter the host system. The fate of these peptidoglycan fragments, and the outcome for the host, depends on the molecular nature of the peptidoglycan, as well the cellular profile of the recipient tissue, mechanism of cell entry, the expression of specific processing and recognition mechanisms by the cell, and the local immune context. At the target level, physiological processes modulated by peptidoglycan are extremely diverse, ranging from immune activation to small molecule metabolism, autophagy and apoptosis. In this review, we bring together a fragmented body of literature on the kinetics and dynamics of peptidoglycan interactions with the mammalian host, explaining how peptidoglycan functions as a signalling molecule in the host under physiological conditions, how it disseminates within the host, and the cellular responses to peptidoglycan.

The Role of Visceral Transplantation for Neoplastic Disease

Visceral transplantation has been utilized as the most radical surgical treatment for neoplasms not amenable to conventional resection. The main indications for this procedure include mesenteric desmoid tumors threatening the root of mesentery and metastatic neuroendocrine neoplasms. Published case-series of visceral transplantation for such indications are reviewed in this article. Patients with desmoid tumors associated with familial adenomatous polyposis are transplanted with intestinal or multivisceral allografts. With surgical modification of technique, the native spleen is preserved while duodenopancreatic complex is removed to obviate the risk of malignant transformation of duodenal polyposis after transplantation. Preservation of spleen decreased incidence of post-transplant lymphoproliferative disorder, conferring therapeutic advantage. Patient survival is comparable to that of other indications, and desmoid tumor recurrence has been observed in the recipient tissue but not in the donor allograft. For visceral transplantation of metastatic neuroendocrine neoplasms, the majority of these patients have diffuse liver involvement, thus requiring full multivisceral transplantation. Post-transplant patient survival is acceptable with limited data available on recurrence. Autotransplantation following ex vivo tumor resection using visceral allografts has been also performed in a limited, select cohort of patients with various pathologies. Adenocarcinomas are associated with a prohibitive recurrence rate following the procedure, and its use for this indication is therefore not recommended. A national database of visceral transplantation undertaken for neoplastic disease should be developed to better understand predictors of outcomes and to help produce and standardize selection criteria.

Quantification of the foreign body reaction by means of a miniaturized imaging window for intravital nonlinear microscopy

Brand new biomaterials, intended to be used on humans, must undergo in vivo quantification standardized, expensive and unethical procedures mainly based on histopathological analysis, from dissections, as defined by the ISO 10993 normative set. The aim is to prove the biomaterials biocompatibility. There exist no methods based on intravital microscopy able to satisfy the normative quantification requirements both reducing the number of employed animals and related costs. We developed a miniaturized imaging window, the Microatlas, which allows subcutaneous repeated observations in vivo of the foreign body reactions, for example to the implantation of a biomaterial. Confocal and twophoton microscopy inspections at Microatlas implantation sites demonstrated growth of the recipient tissue inside the microgrids both with micro vascularization formation and collagen generation. In conclusion, the Microatlas guided in vivo a quantifiable localized reaction inside its microscaffold, both in terms of cell repopulation, collagen and capillary formation as a probable foreign body reaction.

Introduction

Plastic surgery techniques, developed over the preceding 5,000 years, outline the chapters in the second edition of this original book, along with patient considerations. Chapters address the assessment of the defect, the preoperative factors in addressing the problem at hand, the influence of medical or adjuvant therapy, the pathology of the defect, the role of trauma in operative repair, and the correct marriage of donor to recipient tissue. Contributors also address operative indications, operative room setup, and postoperative care and details of pertinent dressings. Plastic surgery has evolved from the transfer of local, pedicle, and free flaps to the understanding of the requirements for angiogenesis and the physiology of tissue molding. Future discoveries will open new avenues for treatment and care.

CELL AND TISSUE THERAPY OF HEART

The strategy of heart tissue engineering is simple enough: first remove all the cells from a organ then take the protein scaffold left behind and repopulate it with stem cells immunologically matched to the patient in need. While various successful methods for decellularization have been developed, and the feasibility of using decellularized whole hearts and extracellular matrix to support cells has been demonstrated, the reality of creating whole hearts for transplantation and of clinical application of decellularized extracellular matrix-based scaffolds will require much more research. For example, further investigations into how lineage-restricted progenitors repopulate the decellularized heart and differentiate in a site-specific manner into different populations of the native heart would be essential. The scaffold heart does not have to be human. Pig hearts carries all the essential components of the extracellular matrix. Through trial and error, scaling up the concentration, timing and pressure of the detergents, researchers have refined the decellularization process on hundreds of hearts and other organs, but this is only the first step. Further, the framework must be populated with human cells. Most researchers in the field use a mixture of two or more cell types, such as endothelial precursor cells to line blood vessels and muscle progenitors to seed the walls of the chambers. The final challenge is one of the hardest: vascularization, placing a engineered heart into a living animal, integration with the recipient tissue, and keeping it beating for a long time. Much remains to be done before a bioartificial heart is available for transplantation in humans.

CELL AND TISSUE THERAPY OF HEART

The strategy of heart tissue engineering is simple enough: first remove all the cells from a organ then take the protein scaffold left behind and repopulate it with stem cells immunologically matched to the patient in need. While various suc- cessful methods for decellularization have been developed, and the feasibility of using decellularized whole hearts and extracellular matrix to support cells has been demonstrated, the reality of creating whole hearts for transplantation and of clinical application of decellularized extracellular matrix-based scaffolds will require much more research. For example, further investigations into how lineage-restricted progenitors repopulate the decellularized heart and differentiate in a site-specific manner into different populations of the native heart would be essential. The scaffold heart does not have to be human. Pig hearts carries all the essential components of the extracellular matrix. Through trial and error, scaling up the concentration, timing and pressure of the detergents, researchers have refined the decellularization process on hundreds of hearts and other organs, but this is only the first step. Further, the framework must be populated with human cells. Most researchers in the field use a mixture of two or more cell types, such as endothelial precursor cells to line blood vessels and muscle progenitors to seed the walls of the chambers. The final challenge is one of the hardest: vasculariza- tion, placing a engineered heart into a living animal, integration with the recipient tissue, and keeping it beating for a long time. Much remains to be done before a bioartificial heart is available for transplantation in humans.

Angiogenic Synergistic Effect of Adipose-Derived Stromal Cell Spheroids with Low-Level Light Therapy in a Model of Acute Skin Flap Ischemia

Human adipose-derived mesenchymal stem cells (hASCs) are an attractive cell source for tissue engineering. However, one obstacle to this approach is that the transplanted hASC population can decline rapidly in the recipient tissue. The aim of this study was to investigate the effects of low-level light therapy (LLLT) on transplanted spheroid hASCs in skin flaps of mice. hASCs were cultured in monolayers or spheroids. LLLT, hASCs, spheroids and spheroids transplanted with LLLT were applied to the skin flaps. Healing of the skin flaps was assessed by gross evaluation and by hematoxylin and eosin staining and elastin van Gieson staining. Compared with the spheroid group, skin flap healing was enhanced in the spheroid + LLLT group, including the neovascularization and regeneration of skin appendages. The survival of hASCs was enhanced by decreased apoptosis of hASCs in the skin flaps of the spheroid + LLLT group. The secretion of growth factors was stimulated in the spheroid + LLLT group compared with the ASC and spheroid groups. These data suggest that LLLT was an effective biostimulator of spheroid hASCs in the skin flaps, enhancing the survival of hASCs and stimulating the secretion of growth factors.