Autogenous Arteriovenous Bundle Implantation Maintains Viability Without Increased Immune Response in Large Porcine Bone Allotransplants.

BACKGROUND: Transplantation of living allogeneic bone segments may permit reconstruction of large defects, particularly if viability is maintained without immunosuppression. Development of a new autogenous osseous blood supply accomplishes this goal in rodent experimental models. This study evaluates potential systemic and local inflammatory responses to this angiogenesis in a large-animal model. METHODS: Vascularized allogeneic tibia segments were transplanted orthotopically into matched tibial defects in Yucatan minipigs. Microvascular anastomoses of bone nutrient artery and vein were supplemented by intramedullary placement of an autogenous arteriovenous (AV) bundle in group 1. Group 2 served as a no-angiogenesis control. A 3-drug immunosuppression regimen was withdrawn after 2 weeks. During the 20-week survival period, periodic leukocyte counts and inflammatory cytokine levels were measured. Thereafter, osteocyte survival was quantified and transplant rejection graded by histologic examination and quantitative real-time polymerase chain reaction of immunologic markers. RESULTS: Both groups developed an initial systemic response, which resolved after 4 to 6 weeks. No differences were seen in blood cytokine levels. Interleukin 2 expression was diminished in group 1 tibiae. As expected, nutrient pedicles had thrombosed without sustained immunosuppression, occluded by intimal hyperplasia. In group 1, angiogenesis from the autogenous AV bundle resulted in significantly less osteonecrosis (P = .04) and fibrosis (P = .02) than group 2 allotransplants. CONCLUSIONS: Systemic immune responses to large-bone allotransplants were not increased by generation of an autogenous osseous blood supply within porcine tibial bone allotransplants. Implanted AV bundles diminished inflammation and fibrosis and improved bone viability when compared to no-angiogenesis controls.

Autograft immune content and survival in non-Hodgkin's lymphoma: A post hoc analysis.

The infusion of autograft absolute lymphocyte and monocyte counts affect survival in patients undergoing autologous peripheral hematopoietic stem cell transplantation (APHSCT). However, the specific autograft immune effector cells affecting survival post-APHSCT are unknown. Thus, we performed an ad hoc analysis from our published double-blind, randomized phase III clinical trial in non-Hodgkin's lymphoma (NHL) patients, looking at the infused autograft immune effector cells and their relationship with clinical outcomes post-APHSCT. Between December 2007 and October 2010, we performed a double-blind phase III randomized study registered with ClinicalTrials.gov, number NCT00566228. A total of 111 patients finished the trial and apheresis collection samples were analyzed for immune effector cells. Overall survival (OS) and progression-free survival (PFS) were calculated from the date of APHSCT. With a median follow-up of 82.8 months (range: 2.1-122.3 months), we identified by univariate analysis that the autograft numbers of macrophage type 1 (M 1), macrophage type 2 (M 2), dendritic cell type 1 (DC 1), dendritic cell type 2 (DC 2), myeloid-derived suppressor cells (MDSC), CD4+PD-1-, CD4+PD-1+, CD8+PD-1-, CD8+PD-1+, lymphocyte to monocyte ratio (A-LMR), NKp30, and KIR2DL2, were predictors for OS and PFS. Multivariate analysis revealed that A-LMR, MDSC, NKp30, KIR2DL2 and lactate dehydrogenase were independent predictors for OS. Independent predictors for PFS identified by multivariate analysis included DC1, MDSC, NKp30, CD4+PD-1- and M 2. Our findings indicate that the number of specific infused autograft immune effector cells affect survival ; thus providing a platform to develop an immunocompetent autograft with direct impact on clinical outcomes in NHL post-APHSCT.

Evaluation of the host immune response and functional recovery in peripheral nerve autografts and allografts.

Allogeneic peripheral nerve (PN) transplants are an effective bridge for stimulating regeneration of segmental PN defects, but there are currently no detailed studies about the timeline and scope of the immunological response for PN allografting. In this study, the cellular immune response in PN allografts and autograft was studied during the acute and chronic phases of a 1.0 cm critical size defect in the rat sciatic nerve at 3, 7, 14, 28 and 98 days after grafting autologous or allogeneic nerves without any immunosuppressive treatment. The assessment was based on functional, histomorphometrical and immunohistochemical criteria. Results showed modestly better functional outcomes for autografts with coordinate and adaptive immune response represented by the presence of CD11c, CD3, CD4, NKp46 and CD8 cells at 3 days, CD45R positive cells and CD25 positive cells at seven and CD45R positive cells at 14 days which seems an adaptive immune response. In contrast, allograft in the early time points showed innate immune response instead of adaptive immune response until day 14, when there was some increase in cell-mediated immunity. In conclusion, in PN autografts the immune system is synchronic initiating with a more robust early innate response that more rapidly transitions to adaptive while for PN allografts the infiltration of immune cells is slower and more gradually progresses to a moderate adaptive response.

The Disturbed Function of Neutrophils at the Early Stage of Fat Grafting Impairs Long-Term Fat Graft Retention.

BACKGROUND: Fat grafting is a popular soft-tissue filler method; however, the mechanism of its survival and regeneration is still not fully understood. Neutrophils are the frontier inflammatory cells and closely associated with tissue regeneration. To understand the role of neutrophils in fat graft retention, we adopted neutrophil depletion and up-regulation models. METHODS: Mouse inguinal fat (approximately 200 mg) was transferred autologously. The anti-mouse Ly6G antibody and lipopolysaccharides were used in the mouse fat grafting model for neutrophil depletion or activation, respectively. We examined the blood and graft stromal vascular fraction by fluorescence-activated cell sorting in manipulation/control groups. Graft weight, vascularization, and secreted factors were also compared. RESULTS: There was a significant reduction/increase of neutrophil counts in the circulation and the transferred fat before day 7 with Ly6G antibody/lipopolysaccharides treatment. Early depletion of neutrophils resulted in incompetent angiogenesis and eventually a poor retention rate (27 ± 8 percent) compared with control (51 ± 10 percent; p < 0.05), whereas up-regulated neutrophils increased the inflammation and reactive oxygen species level, leading to tissue damage and poor retention rate (20 ± 9 percent) compared with control (51 ± 10 percent; p < 0.05). Enhanced macrophage infiltration could be found in both neutrophil depletion and up-regulation groups after week 4. CONCLUSIONS: Undisturbed neutrophil function is the key to initiating downstream responses of macrophage infiltration, stimulating vessel formation, and regulating inflammation level; thus, it exerts a great impact on the long-term retention rate. Disturbed neutrophil function, either enhanced or weakened, can lead to impaired fat graft retention.

Autograft immune effector cells and survival in autologous peripheral blood hematopoietic stem cell transplantation.

In addition to stem cells, T-cells, natural killer cells, dendritic cells, and monocytes are also collected and infused from the autograft in patients undergoing autologous peripheral blood hematopoietic stem cell transplantation. Recent reports have shown that these autograft immune effector cells can affect the clinical outcome postautologous peripheral blood hematopoietic stem cell transplantation. In this article, I will review the clinical impact on the survival of these autograft immune effector cells conferring the concept of autologous graft versus tumor effect.

Germline Stem Cells: A Useful Tool for Therapeutic Cloning.

BACKGROUND: Numerous articles have been published on the potential of using embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) in clinical applications. As these types of stem cell are well studied, the research on germline stem cells (GSCs), which hold a huge potential for clinical application and permanent treatment for infertility, is left behind. Besides possessing the characteristics of being able to self-renew and to give rise to differentiated progeny throughout postnatal life, the potential of GSCs to transform into pluripotent status is remarkable but is unexploited. OBJECTIVE: To explore the potential of germline stem cells in therapeutic usage, it's required to understand the underlying transformation mechanism of germline stem cells into pluripotent cells. RESULTS: In this review, we summarized development of ESCs, GSCs, iPSCs, and embryonic stem-like (ES-like) cells derived from GSCs, discussed feasibility and the technical hurdles of using these types of stem cells in therapeutic cloning, and finally focused on the comparison of the ESCs, iPSCs and ESlike cells in current as well as potential applications in medicine. Moreover, the prospects of female germline stem cells (FGSCs) and their derived ES-like cells were also discussed as a novel alternative in clinical application. CONCLUSION: With the capacity of germline reconstitution and transformation into pluripotent status, GSCs possess significant potential for clinic usage and therapeutic cloning.

Depigmentation during vitiligo activity spares epithelial grafted areas.

BACKGROUND: Vitiligo is a depigmenting disease characterized by episodes of stability and activity without a fixed sequence, and active phases demonstrate immune attacks toward vulnerable melanocytes. Epithelial grafts were introduced to treat recalcitrant vitiligo patches aiming to provide new generations of melanocytes. AIMS: The aim of study was to evaluate the possible permanency of succeeded epithelial grafts during a coming activity episode. METHODS: This study included 20 nonsegmental vitiligo cases. They were epithelial grafted, success was maintained with the use of UV sessions for a year, and further follow-up was allowed until new phases of activity developed. RESULTS: The grafted areas, in all cases, were spared during the activity episodes in spite of the development of new depigmented lesions in other parts of skin neighboring the grafted areas or in remote sites. CONCLUSION: The permanency of epithelial grafts in spite of disease reactivity is a good sign and magnifies the value of surgical approaches in management of vitiligo. New genetically different melanocytes should have been provided and were able to resist the new immune attacks in spite of the yielding of other skin melanocytes.

Stem cell autograft and allograft in autoimmune diseases.

Autoimmune diseases are characterized by an insufficiency of immune tolerance and, although treated with a number of useful drugs, may need more unconventional therapeutic strategies for their more severe presentations. Among such unconventional therapeutic approaches, stem cell autograft and allograft have been used, with the aim of stimulating disease remission by modifying the pathogenic mechanisms that induce anomalous responses against self-antigens. Autologous transplantation is performed with the purpose of retuning autoimmune cells, whereas allogeneic transplantation is performed with the purpose of replacing anomalous immune effectors and mediators. In this article, we comprehensively review up-to-date information on the autoimmune diseases for which the transplantation of stem cells is indicated.

Alternatively activated M2 macrophages improve autologous Fat Graft survival in a mouse model through induction of angiogenesis.

BACKGROUND: Variability in graft retention with subsequent undercorrection remains a significant limitation of autologous fat grafting. The authors evaluated whether graft retention in a mouse model could be improved via graft supplementation with alternatively activated M2 macrophages, cells known to play a critical role in tissue repair. METHODS: Grafts from C57BL/6 mouse inguinal fat pads were supplemented with M2 macrophages generated by intraperitoneal Brewer's thioglycollate injection and in vitro culture. Grafts with saline or M2 macrophages were injected under recipient mouse scalps and assessed by serial micro-computed tomographic analysis. Explanted grafts underwent immunohistochemical and flow cytometric analyses. M2 culture supernatants were added to stromal vascular fraction adipose-derived stem cells to assess adipogenic gene expression induction. RESULTS: One month after graft injection, no significant difference was noted between M2 macrophage-supplemented (105 ± 7.0 mm) and control graft volumes (72 ± 22 mm). By 3 months after injection, M2 macrophage-supplemented grafts remained stable, whereas controls experienced further volume loss (103 ± 8 mm versus 39.4 ± 15 mm; p = 0.015). Presence of macrophages in supplemented grafts was confirmed by flow cytometry. M2 macrophage-supplemented grafts exhibited a 157 percent increase in vascular density compared with controls (p < 0.05). Induction of adipogenic C/EBPα gene expression was observed with M2 supernatants addition to stromal vascular fraction adipose-derived stem cells. CONCLUSIONS: M2 macrophages improve autologous fat graft volume retention by stimulating angiogenesis. These findings provide proof-of-principle for development of fat grafting techniques that harness reparative properties of M2 macrophages.