Basic fibroblast growth factor-impregnated collagen gelatin sponge completes formation of dermis-like tissue within 2 weeks: A prospective cohort study

Introduction

Methods

Results

Conclusion

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This study examined the usefulness of bFGF-CGS for skin defects.

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bFGF-CGS completes dermis-like tissue within 2 weeks.

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bFGF-CGS rapidly achieved wound closure of acute full-thickness skin defects.

Corrigendum to "Dedifferentiated fat cells in polyglycolic acid-collagen nerve conduits promote rat facial nerve regeneration" [Regen Ther 11 (2019) 240-248]

[This corrects the article DOI: 10.1016/j.reth.2019.08.004.].

Alda-1, an Aldehyde Dehydrogenase 2 Agonist, Improves Cutaneous Wound Healing by Activating Epidermal Keratinocytes via Akt/GSK-3β/β-Catenin Pathway

BACKGROUND

The cutaneous wound healing process mainly comprises re-epithelialization, fibrosis, and neovascularization. Impaired wound healing is common but tricky in plastic surgery. Aldehyde dehydrogenase 2 (ALDH2), the most effective subset of the ALDH enzyme family, is known to exert a major role in detoxification of aldehydes. Activation of ALDH2 by Alda-1 (a specific agonist) has been found to protect against cardiovascular diseases. However, no research has paid attention to the potential of ALDH2 activation in regulating wound healing. The previous studies suggested a high expression of ALDH2 in normal skin tissue. The aim of this study was to investigate if Alda-1 may ameliorate wound healing.

METHODS

A full-thickness excisional wound model was established in vivo. Adult male C57BL/6 mice were randomly divided into DMSO and Alda-1 groups. Mice received an intraperitoneal injection of DMSO or 10 mg/mL Alda-1 (10 mg/kg body weight, dissolved in DMSO) for 7 days. The wound healing rate was measured at 0, 3, 5, and 7 days. Distribution of ALDH2 in wound tissue was showed. ALDH2 enzymatic activity was examined at 3, 5, and 7 days. The elongation of epithelial tongue was detected by hematoxylin-eosin staining, and collagen deposition was analyzed by Masson's trichrome staining at 7 days. Expressions of alpha-smooth muscle actin (alpha-SMA), transforming growth factor beta (TGF-beta), CD31, collagen 1, collagen 3, and elastin were stained by immunohistochemistry at 5 and 7 days. The HaCaT cell line was applied in vitro. Proliferation and migration were tested using CCK8 and wound healing assay separately. The level of TGF-β was examined by ELISA. Protein levels of the Akt/glycogen synthase kinase-3 beta (GSK-3 beta)/beta-catenin pathway were determined by western blotting.

RESULTS

Alda-1 accelerated wound healing rates. ALDH2 activity in wound sites was restored. Alda-1 promoted the length of the epithelial tongue, collagen deposition, as well as expressions of alpha-SMA, TGF-beta, collagen 1/3, elastin, but did not affect CD31. Proliferation, migration, and TGF-β secretion were promoted by Alda-1 and deregulated by CVT-10216 (an ALDH2 inhibitor). Protein variations of the Akt/GSK-3β/β-catenin pathway were found to accord with ALDH2 changes.

CONCLUSIONS

Alda-1, an ALDH2 agonist, improves cutaneous wound healing in a full-thickness excisional wound model. Alda-1 activates proliferation, migration, and TGF-β secretion of HaCaT (epidermal keratinocytes) by regulating the Akt/GSK-3β/β-catenin pathway.

NO LEVEL ASSIGNED

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Dedifferentiated fat cells in polyglycolic acid-collagen nerve conduits promote rat facial nerve regeneration

Introduction

Polyglycolic acid (PGA) nerve conduits, an artificial biodegradable nerve regeneration-inducing tube currently used in clinical practice, are effective in regenerating peripheral nerves. Dedifferentiated fat (DFAT) cells differentiate into various cells including adipocytes, osteoblasts, chondrocytes, skeletal muscle cells, and myofibroblasts, when cultured in appropriate differentiation-inducing conditioned culture medium. This study made a hybrid artificial nerve conduit by filling a PGA conduit with DFAT cells, applied the conduit to a rat facial nerve defect model, and investigated the facial nerve regenerative ability of the conduit.

Methods

Under inhalational anesthesia, the buccal branch of the facial nerve in Lewis rats was exposed, and a 7-mm nerve defect was created. PGA nerve conduits were filled with DFAT cells, which were prepared from rat subcutaneous adipose tissue with type I collagen as a scaffold, and then grafted into the nerve defect sites in rats with a microscope (DFAT group) (n = 10). In other rats, PGA artificial nerve conduits alone were similarly grafted into the nerve defect sites (the control group) (n = 10). Reinnervation was confirmed at 13 weeks postoperatively by a retrograde tracer, followed by histological and physiological comparative studies.

Results

The mean number of myelinated fibers was significantly higher in DFAT group (1605 ± 806.23) than in the control group (543.6 ± 478.66). Myelin thickness was also significantly lager in DFAT group (0.57 ± 0.17 μm) than in the control group.

(0.46 ± 0.14 μm). Although no significant difference was found in the amplitude of compound muscle action potential (CMAP) between DFAT group (2.84 ± 2.47 mV) and the control group (0.88 ± 0.56 mV), whisker motion was lager in DFAT group (9.22° ± 0.65°) than in the control group (1.9° ± 0.84°).

Conclusions

DFAT cell-filled PGA conduits were found to promote nerve regeneration in an experimental rat facial nerve defect model.

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PGA artificial conduits containing DFAT cells were made in this study.

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The facial nerve regenerative ability of conduits was evaluated in a rat model.

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Reinnervation was confirmed at 13 weeks postoperatively.

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The nerve regeneration promoting effect of DFAT cells was found in the model.

Full-thickness skin reconstruction with basic fibroblast growth factor-impregnated collagen-gelatin sponge

Introduction

This study examined the usefulness of basic fibroblast growth factor impregnated collagen-gelatin sponge (bFGF-CGS) in reconstructive surgery for various acute skin defects including deep dermal burns, facial full-thickness skin defects, and finger amputations as the first clinical application.

Methods

Reconstructive surgery was performed in two stages with bFGF-CGS in 8 male subjects, ranging in age from 6 to 84 years, with acute full-thickness skin defects. Following the adequate debridement of the defect, surgeons prepared a bFGF-CGS with bFGF solution at a dose of 7–14 mg/cm² approximately 10 min just before application and then secured the bFGF-CGS in place with non-absorbable sutures. Second-stage wound closure was performed with autologous skin grafting following adequate dermis-like tissue regeneration at the site postoperatively. Follow-up was continued for 6 months.

Results

Of the 8 subjects, the mean duration from the adequate vascularization of the dermis-like tissue until the second-stage autologous skin graft was 22 ± 4 days. Wound closure was achieved in all cases; the mean duration until wound closure was 32 ± 8 days. During the 6-month follow-up period, no wound infection, recurrent skin ulceration, and no exposure of tendon, bone, and cartilage were observed, and there were no cases of indirectly restricted range of motion from postoperative scar contracture and none with disfiguring scars.

Conclusion

The authors achieved favorable outcomes following reconstructive surgery with a hybrid artificial dermis impregnated with bFGF for treating acute full-thickness skin defects. bFGF-CGS serves as a convenient regenerative device requiring no specialized medical facilities.

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This study examined the usefulness of bFGF-impregnated collagen gelatin sponge for skin defects.

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bFGF-CGS achieved wound closure with acute full-thickness skin defects in a short period of time.

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bFGF-CGS is a convenient device without requiring specialized medical facilities.

Effect of Mature Adipocyte-Derived Dedifferentiated Fat Cells on Formation of Basement Membrane after Cultured Epithelial Autograft on Artificial Dermis

BACKGROUND

Artificial dermis is an important option for preparing full-thickness wounds for cultured epithelial autografting. Long-term fragility after cultured epithelial autografting remains a problem, probably because of the lack of basement membrane proteins. The authors hypothesized that treating artificial dermis with mesenchymal stem cells would promote basement membrane protein production. The authors tested this using dedifferentiated fat cells in a porcine experimental model.

METHODS

This study used four male crossbred (Landrace, Large White, and Duroc) swine. Cultured epithelium and dedifferentiated fat cells were prepared from skin and subcutaneous fat tissue harvested from the cervical region. Full-thickness open dorsal wounds were created and treated with artificial dermis to prepare a graft bed for cultured epithelial autograft. Two groups were established: the control group (artificial dermis treated with 0.5 ml of normal saline solution applied to the wounds) and the dedifferentiated fat group (artificial dermis treated with 0.5 × 10 dedifferentiated fat cells suspended in 0.5 ml of normal saline solution sprayed onto the wounds). On postoperative day 10, the prepared cultured epithelium was grafted onto the generated dermis-like tissue. Fourteen days later, tissue specimens were harvested and evaluated histologically.

RESULTS

Light microscopy of hematoxylin and eosin-stained sections revealed the beginning of rete ridge formation in the dedifferentiated fat group. Synthesis of both collagen IV and laminin-5 was significantly enhanced in the dedifferentiated fat group. Transmission electron microscopy revealed a nearly mature basement membrane, including anchoring fibrils in the dedifferentiated fat group.

CONCLUSION

Combined use of artificial dermis and dedifferentiated fat cells promotes post-cultured epithelial autograft production and deposition of basement membrane proteins at the dermal-epidermal junction and basement membrane development, including anchoring fibrils.

Adipose-derived stem cells and the stromal vascular fraction in polyglycolic acid-collagen nerve conduits promote rat facial nerve regeneration

Adipose-derived stem cells (ADSCs) and the stromal vascular fraction (SVF) promote nerve regeneration. Biodegradable nerve conduits are used to treat peripheral nerve injuries, but their efficiencies are lower than those of autologous nerve grafts. This study developed biodegradable nerve conduits containing ADSCs and SVF and evaluated their facial nerve regenerating abilities in a rat model with a 7-mm nerve defect. SVF and ADSCs were individually poured into nerve conduits with polyglycolic acid-type I collagen as a scaffold (ADSCs and SVF groups). The conduits were grafted on to the nerve defects. As the control, the defect was bridged with polyglycolic acid-collagen nerve conduits without cells. At 13 weeks, after transplantation, the regenerated nerves were evaluated physiologically and histologically. The compound muscle action potential of the SVF group was significantly higher in amplitude than that of the control group. Electron microscopy showed that the axon diameter of the SVF group was the largest, followed by the ADSC group and control group with significant differences among them. The SVF group had the largest fiber diameter, followed by the ADSC group and control group with significant differences among them. The ADSC group had the highest myelin thickness, followed by the SVF group and control group with significant differences among them. Identical excellent promoting effects on nerve regeneration were observed in both the ADSC and SVF groups. Using SVF in conduits was more practical than using ADSCs because only the enzymatic process was required to prepare SVF, indicating that SVF could be more suitable to induce nerve regeneration.

Delivery systems of current biologicals for the treatment of chronic cutaneous wounds and severe burns

While wound therapy remains a clinical challenge in current medical practice, much effort has focused on developing biological therapeutic approaches. This paper presents a comprehensive review of delivery systems for current biologicals for the treatment of chronic wounds and severe burns. The biologicals discussed here include proteins such as growth factors and gene modifying molecules, which may be delivered to wounds free, encapsulated, or released from living systems (cells, skin grafts or skin equivalents) or biomaterials. Advances in biomaterial science and technologies have enabled the synthesis of delivery systems such as scaffolds, hydrogels and nanoparticles, designed to not only allow spatially and temporally controlled release of biologicals, but to also emulate the natural extracellular matrix microenvironment. These technologies represent an attractive field for regenerative wound therapy, by offering more personalised and effective treatments.

Lull pgm system: A suitable technique to improve the regenerative potential of autologous fat grafting

Autologous fat grafting and methods of purification of harvested tissue have become one of the most current themes in regenerative medicine. The aim of this study was to evaluate the in vitro regenerative potential of abdomen lipoaspirates subjected to a combined washing-decantation purifying procedure, the Lull pgm System (Lull). Blood cells and stromal-vascular fraction (SVF) cells contained in the aspirates were investigated and compared with those obtained through more conventional fat-processing methods, that is, the decantation and Coleman's centrifugation techniques. The lowest number of erythrocytes, which are proinflammatory cells, was observed in the Lull samples, corresponding to about 50% of those isolated by decantation and centrifugation. The highest amount of SVF cells were isolated from the Lull samples whose number of colony forming units, representative of the amount of adipose-derived stem cells (ADSCs), was about fourfold and sixfold higher than in the decantation and centrifugation samples, respectively. Adipocyte and osteoblast commitment of SVF cells obtained from all the three procedures also confirmed that the subpopulation of ADSCs was actively represented in the processed aspirates. Moreover, the growth rate of the SVF cells was more accentuated in the samples obtained from decantation and Lull than centrifugation. In conclusion, Lull seems to be the best processing technique for adipose tissue graft with respect to decantation and centrifugation, because it clears more efficiently the fat from proinflammatory blood cells and provides the greatest number of proliferating SFV cells and ADSCs.

Cell viability and extracellular matrix synthesis in a co-culture system of corneal stromal cells and adipose-derived mesenchymal stem cells

AIM

To investigate the impact of adipose-derived mesenchymal stem cells (ADSCs) on cell viability and extracellular matrix (ECM) synthesis of corneal stromal cells (CSCs).

METHODS

ADSCs and CSCs were obtained from the corneas of New Zealand white rabbits and indirectly co-cultured in vitro. The proliferative capacity of CSCs in the different groups was assessed by CCK-8 assays. Annexin V-fluorescein isothiocyanate (FITC)/proliferation indices (PI) assays were used to detect the apoptosis of CSCs. The expression levels of matrix metalloproteinase (MMP), such as MMP1, MMP2, MMP9, and collagens were also evaluated by Western blot.

RESULTS

ADSCs significantly promoted proliferation and invasion of CSCs in the indirect co-culture assays. The co-cultural group displayed much higher ability of proliferation, especially under the co-culture conditions of ADSCs for 3d, compared with that CSCs cultured alone. The PI of CSCs in the co-culture system were increased approximately 3-8-fold compared with the control group. A significant change was observed in the proportions of cells at apoptosis (early and late) between the negative control group (6.34% and 2.06%) and the ADCSs-treated group (4.69% and 1.59%). The expression levels of MMPs were down regulated in the co-culture models. Compared with the control group, the decrease intensities of MMP-1, MMP-2 and MMP-9 in CSCs/ADSCs group were observed, 3.90-fold, 1.09-fold and 3.03-fold, respectively. However, the increase intensities of collagen type (I, II, III, IV, and V) in CSCs were observed in CSCs/ADSCs group, 3.47-fold, 4.30-fold, 2.35-fold, 2.55-fold and 2.43-fold, respectively, compared to that in the control group. The expressions of aldehyde dehydrogenase and fibronectin in CSCs were upregulated in the co-culture models.

CONCLUSION

ADSCs play a promotive role in CSCs' growth and invasion, which may be partially associated with MMPs decrease and collagens increase, resulting in a positive participation in the plasticity and ECM synthesis of CSCs. This provided a new insight into the extensive role of ADSCs in CSCs and a potential molecular target for corneal therapy.