Cell therapy for wound healing

Altered protein secretions during interactions between adipose tissue- or bone marrow-derived stromal cells and inflammatory cells

Introduction

Paracrine effects can be exploited in cell-based therapies that secrete factors, such as chemokines and cytokines, and can recruit inflammatory cells to transplants. In this study, mouse adipose tissue-derived stromal cells (ASCs) and bone marrow-derived stromal cells (ST2 cells) were used to examine changes in paracrine interactions with inflammation cells.

Methods

Green fluorescent protein positive (GFP⁺) bone marrow cells (BMCs) were injected into an irradiated mouse via the femoral vein, and ASCs and ST2 cells were transplanted intradermally. Subsequently, an in vivo imaging system was used to observe behaviors of GFP⁺ BMCs. To detect bone marrow-derived inflammatory cells which migrated to the ASC and ST2 cell transplantation area, the sections were immunostained using antibodies against Gr1, CD11c, and F4/80, and secretory proteins were detected in culture medium using enzyme-linked immunosorbent assay.

Results

Many bone marrow-derived inflammatory cells migrated to ASC and ST2 cell transplantation sites. Among these, neutrophils were detected during the early period and macrophages were predominantly detected at a later point in time. Many chemokines, cytokines, growth factors, matrix metalloproteinases (MMPs), and tissue inhibitors of metalloproteinases (TIMPs) were secreted in abundance from ASCs, and the secretion increased by co-culturing with inflammatory cells, except for secretions of insulin-like growth factor-1, MMP-9 and MMP-13. Although secretions from ST2 cells were less than those from ASCs, co-culture with inflammatory cells increased these secretions to levels similar to those of ASCs. However, unlike ASCs, the ST2 cells did not secrete angiostatin, MMP-2, or MMP-3. Finally, ASCs secreted not only proinflammatory cytokines, angiogenic factors and MMPs but also anti-inflammatory cytokines, anti-angiogenesis factors, and TIMPs.

Conclusions

The effects of cell-based therapies using ASCs and ST2 cells are depended on paracrine effects that are mediated by chemokines, cytokines, growth factors, MMPs, and TIMPs, which comprise responses to interactions between transplanted cells and inflammatory cells. Moreover, paracrine effects of transplanted cells are influenced by inflammatory cells, and are moderated by a balance of secreted inhibitors.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0052-y) contains supplementary material, which is available to authorized users.

Microporous dermal-mimetic electrospun scaffolds pre-seeded with fibroblasts promote tissue regeneration in full-thickness skin wounds

Electrospun scaffolds serve as promising substrates for tissue repair due to their nanofibrous architecture and amenability to tailoring of chemical composition. In this study, the regenerative potential of a microporous electrospun scaffold pre-seeded with dermal fibroblasts was evaluated. Previously we reported that a 70% collagen I and 30% poly(Ɛ-caprolactone) electrospun scaffold (70:30 col/PCL) containing 160 μm diameter pores had favorable mechanical properties, supported fibroblast infiltration and subsequent cell-mediated deposition of extracellular matrix (ECM), and promoted more rapid and effective in vivo skin regeneration when compared to scaffolds lacking micropores. In the current study we tested the hypothesis that the efficacy of the 70:30 col/PCL microporous scaffolds could be further enhanced by seeding scaffolds with dermal fibroblasts prior to implantation into skin wounds. To address this hypothesis, a Fischer 344 (F344) rat syngeneic model was employed. In vitro studies showed that dermal fibroblasts isolated from F344 rat skin were able to adhere and proliferate on 70:30 col/PCL microporous scaffolds, and the cells also filled the 160 μm pores with native ECM proteins such as collagen I and fibronectin. Additionally, scaffolds seeded with F344 fibroblasts exhibited a low rate of contraction (~14%) over a 21 day time frame. To assess regenerative potential, scaffolds with or without seeded F344 dermal fibroblasts were implanted into full thickness, critical size defects created in F344 hosts. Specifically, we compared: microporous scaffolds containing fibroblasts seeded for 4 days; scaffolds containing fibroblasts seeded for only 1 day; acellular microporous scaffolds; and a sham wound (no scaffold). Scaffolds containing fibroblasts seeded for 4 days had the best response of all treatment groups with respect to accelerated wound healing, a more normal-appearing dermal matrix structure, and hair follicle regeneration. Collectively these results suggest that microporous electrospun scaffolds pre-seeded with fibroblasts promote greater wound-healing than acellular scaffolds.

[Regenerative therapy approaches in plastic surgery]

BACKGROUND

The regeneration of tissue lost due to trauma or disease is considered as being ideal for reconstruction with respect to repair in which a donor defect arises in a different part of the body. Through a better understanding of the cellular and molecular mechanisms of healing, possibilities for regenerative therapies have been developed in recent years.

OBJECTIVES

To give an exemplary representation of current regenerative therapy approaches and their effect and clinical application.

MATERIAL AND METHODS

The PubMed database was searched for different regenerative approaches in plastic surgery and various methods are presented in this article.

RESULTS

Cell-based approaches, in which autologous mesenchymal stem cells from adipose tissue are preferably used, led to excellent healing results with minimal donor site morbidity. Likewise, growth factor-based approaches or the use of platelet-rich plasma achieve very good results in the field of wound and bone healing.

DISCUSSION

By using different cells or molecules and thus taking advantage of biological mechanisms, the regenerative capabilities of adult organisms could be improved. Many methods have already been implemented in clinical practice, not only in reconstructive but also in aesthetic surgery. However, the success should not conceal the potential risk that is inherent in both cell and growth factor-based approaches. Until long-term experiences of such therapies have been acquired, they should be used cautiously.

Effect of n-butyl-2-cyanoacrylate on the tensile strength and pressure resistance of tracheal anastomoses ex vivo

OBJECTIVES

To investigate the effects of n-butyl-2-cyanoacrylate on tracheal anastomoses in terms of increased tension and intraluminal pressure ex vivo.

STUDY DESIGN

Ex vivo experimental study.

SETTING

Tertiary referral center (Department of Otolaryngology).

SUBJECTS AND METHODS

Thirty sheep tracheas were used. Four cartilage rings were resected from the tracheas that were 20 cm in length. End-to-end anastomoses were performed by using Vicryl only (group 1), Vicryl and n-butyl-2-cyanoacrylate (group 2), and n-butyl-2-cyanoacrylate only (group 3). The amount of force to break off the anastomosis and the amount of intraluminal pressure to arouse air leakage through the anastomosis were measured.

RESULTS

The mean force required to break off was 171.9 ± 29.7 N in group 1, 164.8 ± 26 N in group 2, and 13.52 ± 2 N in group 3. The mean force required to break off in group 3 was significantly lower than those in groups 1 and 2 (P = .008 and P = .008, respectively). The mean pressure required to cause air leakage was 49.6 ± 9.1 mm Hg in group 1, 113 ± 14.4 mm Hg in group 2, and 15 ± 4.2 mm Hg in group 3. Group 2 was found to be more resistant to intraluminal pressure than groups 1 and 3 (P = .008 and P = .008, respectively).

CONCLUSION

n-Butyl-2-cyanoacrylate had no significant effect on tensile strength. However, its application on the suture line provided extra pressure resistance ex vivo. We believe that further studies need to be conducted to investigate its long-term effects and histological impact on tracheal anastomoses in vivo.

Effects of platelet-rich plasma, adipose-derived stem cells, and stromal vascular fraction on the survival of human transplanted adipose tissue

Traditional adipose tissue transplantation has unpredictable viability and poor absorption rates. Recent studies have reported that treatment with platelet-rich plasma (PRP), adipose-derived stem cells (ASCs), and stromal vascular fraction (SVF) are related to increased survival of grafted adipose tissue. This study was the first simultaneous comparison of graft survival in combination with PRP, ASCs, and SVF. Adipose tissues were mixed with each other, injected subcutaneously into the back of nude mice, and evaluated at 4, 8, and 12 weeks. Human adipocytes were grossly maintained in the ASCs and SVF mixtures. Survival of the adipose tissues with PRP was observed at 4 weeks and with SVF at 8 and 12 weeks. At 12 weeks, volume reduction in the ASCs and SVF mixtures were 36.9% and 32.1%, respectively, which were significantly different from that of the control group without adjuvant treatment, 51.0%. Neovascular structures were rarely observed in any of the groups. Our results suggest that the technique of adding ASCs or SVF to transplanted adipose tissue might be more effective than the conventional grafting method. An autologous adipose tissue graft in combination with ASCs or SVF may potentially contribute to stabilization of engraftment.

Stem cell and research in plastic surgery

Regenerative medicine using stem cells has progressed significantly over the last decade. Plastic surgeons historically have used tissues of human being to restore various defect sites and utilized a single cell lines for the tissue regeneration. The cell sources (autologous or allogeneic), cell types (embryonic stem cell or adult stem cell), and source of tissues (bone marrow, muscle, adipose, cartilage, or blood) are very important for stem cell-based tissue coverage. Embryonic stem cells are pluripotent precursors obtained from the inner cell mass of the blastocyst and reported to be used for preventing muscle atrophy after peripheral nerve injury. Multipotent adult stem cells are easily accessed for plastic surgeons during many routine procedures. This article briefly review the current state of overall stem cell research and clinical applications in the plastic surgical field.