The effects of combined application of autogenous fibroblast cell culture and full-tissue skin graft (FTSG) on wound healing and contraction in full-thickness tissue defects

Transcriptomic and in vivo approaches introduced human iPSC-derived microvesicles for skin rejuvenation

The skin undergoes the formation of fine lines and wrinkles through the aging process; also, burns, trauma, and other similar circumstances give rise to various forms of skin ulcers. Induced pluripotent stem cells (iPSCs) have become promising candidates for skin healing and rejuvenation due to not stimulating inflammatory responses, low probability of immune rejection, high metabolic activity, good large-scale production capacity and potentials for personalized medicine. iPSCs can secrete microvesicles (MVs) containing RNA and proteins responsible for the normal repairing process of the skin. This study aimed to evaluate the possibility, safety and effectiveness of applying iPSCs-derived MVs for skin tissue engineering and rejuvenation applications. The possibility was assessed using the evaluation of the mRNA content of iPSC-derived MVs and the behavior of fibroblasts after MV treatment. Investigating the effect of microvesicle on stemness potential of mesenchymal stem cells was performed for safety concerns. In vivo evaluation of MVs was done in order to investigate related immune response, re-epithelialization and blood vessel formation to measure effectiveness. Shedding MVs were round in shape distributed in the range from 100 to 1000 nm in diameter and positive for AQP3, COL2A, FGF2, ITGB, and SEPTIN4 mRNAs. After treating dermal fibroblasts with iPSC-derived MVs, the expressions of collagens Iα1 and III transcripts (as the main fibrous extracellular matrix (ECM) proteins) were upregulated. Meanwhile, the survival and proliferation of MV treated fibroblasts did not change significantly. Evaluation of stemness markers in MV treated MSCs showed negligible alteration. In line with in vitro results, histomorphometry and histopathology findings also confirmed the helpful effect of MVs in skin regeneration in the rat burn wound models. Conducting more investigations on hiPSCs-derived MVs may lead to produce more efficient and safer biopharmaceutics for skin regeneration in the pharmaceutical market.

Evaluation of contraction of the split-thickness skin graft using three dermal matrices in the treatment of burn contractures: a randomized clinical trial

Burn injuries commonly result in serious sequelae (such as skin contractures) in surviving patients, for which no single optimal solution is known. The goal of this study was to compare the late contraction of autologous skin grafts with or without dermal matrices used in the treatment of patients with burn contractures. This parallel design prospective, randomized, and controlled clinical trial included patients with burn contracture treated using autologous skin grafts and dermal matrix. Patients were randomly assigned to one of the four groups: Integra® matrix (n=10), Pelnac® matrix (n=10), Matriderm® matrix (n=9), or a Control Group (n=10, without dermal matrix, only skin graft). The boundaries of skin defect were marked and transferred to a flat sterile surface for area measurement. The current area of the skin grafts was measured during surgery and compared with those obtained at 1, 3, 6, and 12 months postoperatively. Twelve months after surgery, the Control Group presented lower rates of skin graft contraction than Integra® (p<0.01), Matriderm® (p=0.01), and Pelnac® (p<0.01) groups. Pelnac® resulted in larger skin graft contraction than Matriderm® (p<0.01) and Integra® (p=0.02), while differences between Integra® and Matriderm® were not significant (p=0.16). The comparison between intraoperative and 12 months after surgery showed that the worst mean rates of skin graft contraction were from the Pelnac® (51.79%) and Matriderm® (59.17%). In patients with burn contractures, the use of these three dermal matrices did not reduce or avoid the occurrence of late contraction of the skin graft, so their use for this purpose should be carefully evaluated.

Potential of Tissue-Engineered and Artificial Dermis Grafts for Fingertip Reconstruction

BACKGROUND

Management of skin and soft-tissue defects of the fingertips is functionally and aesthetically important, but controversial, especially when bones are exposed. Recent advances in wound healing technology allow the use of cells or biological dermis. The authors studied the clinical efficacy of tissue-engineered dermis grafts and artificial dermis grafts versus immediate reconstructive procedures, such as the reverse digital artery island flap, in treating bone-exposed fingertip defects.

METHODS

One hundred eighty-two patients with bone-exposed fingertip defects treated with tissue-engineered dermis grafts (n = 71), artificial dermis grafts (n = 23), or reverse digital artery island flaps (n = 88) were included in this retrospective cohort study. Surgical time, duration of hospitalization, total cost, success rate, healing time, sensory recovery, range of motion, scar quality, and patient satisfaction were compared.

RESULTS

No tissue-engineered or artificial dermis graft exhibited graft rejection or failure, whereas there was one partial loss and one total loss after reverse digital artery island flap surgery. Tissue-engineered dermis grafts were superior in scar quality, and artificial dermis grafts had shorter surgical times and lower surgical costs; both groups demonstrated superior results in postoperative range of motion and sensory recovery in two-point discrimination tests and shorter hospitalization, compared with the reverse digital artery island flap group. The reverse digital artery island flap had shorter complete closure time and less postoperative tingling sensation. There were no differences in overall patient satisfaction among the groups.

CONCLUSIONS

Tissue-engineered and artificial dermis grafts may be promising alternatives for fingertip reconstruction. In particular, tissue-engineered dermis grafts may deliver superior functional results, including recovery of sensory discomfort and aesthetic results in terms of scar quality over artificial dermis grafts.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Does survivin overexpression enhance the efficiency of fibroblast cell-based wound therapy?

Cell-based wound therapy is faced with some limiting factors that decrease the therapeutic efficacy of transplanted cells. In this study, we aimed to genetically modify fibroblast cells with anti-apoptotic Survivin gene (Birc5) before cell transplantation. In vitro, pIRES2-eGFP-Survivin plasmid was transfected into the fibroblast cells and the growth curve was evaluated for transfected and normal cells performing MTT assay. In vivo, two 6-diameter cutaneous wounds were created at mice dorsal skin. Fibrin clot was used as a delivery vehicle to transfer cells into the wound bed. The effects of four treatment groups including (a) Cell-SVV-Clot (b) Cell-GFP-Clot, (c) Normal cell-Clot and, (d) Clot alone were evaluated. After 1,2,3,7 and 14 days post-transplantation, the wounds were photographed for evaluating the wound closure rate and wound samples were obtained. Angiogenesis and formation of granulated tissue were assessed via H&E staining for wound samples. The expression levels of Survivin, VEGF, and bFGF genes were also determined using qRT-PCR. The MTT assay showed similar proliferation potential of transfected cells with normal cells verifying that Survivin had no detrimental effect. Compared to the Normal cell-Clot group, the Survivin overexpression was seen for 3 days in the Cell-SVV-Clot group verifying the cell survival during the early stage of wound healing. The Survivin further upregulated VEGF and bFGF expressions resulting in more angiogenesis and formation of granulated tissue by day 3 and 14. The treated wounds with Cell-SVV-Clot were regenerated with a higher wound closure rate by day 7 compared to Normal cell-Clot and Clot groups. Survivin enhanced wound healing through induction of VEGF and bFGF at particular times post-wounding that led to a more structured-epidermis with higher angiogenesis and granulation tissue formation rate.

Cell-Assisted Skin Grafting: Improving Texture and Elasticity of Skin Grafts through Autologous Cell Transplantation

BACKGROUND

Full-thickness skin grafts are widely used in plastic and reconstructive surgery. Their poor textural durability and associated contracture make them less desirable than skin flaps. Currently, stromal vascular fraction cells hold great promise because of their angiogenic potential, which may ameliorate the hypoxic period after skin grafting. In this study, autologous transplantation of stromal vascular fraction cells was used in combination with skin grafts to determine whether it improved the texture and other physical property of skin grafts.

METHODS

Stromal vascular fraction cells were isolated and injected under full-thickness skin grafts in a cohort of 20 rats; a second cohort of 20 rats served as controls. Skin grafts were harvested and analyzed on days 14, 30, and 90 after injections. Bioluminescent imaging with luciferase-stromal vascular fraction cells was used for cell tracing. Contracture ratios, elasticity modulus, and the stiffness of each graft were evaluated. Angiogenesis was evaluated using immunohistochemical techniques against vascular endothelial growth factor. Blood flow signals of the graft were also measured, and expression of vascular endothelial growth factor, hepatocyte growth factor, and basic fibroblast growth factor was assessed in all grafts.

RESULTS

Stromal vascular fraction cells markedly decreased the contracture of skin grafts and improved their resilience and elasticity after 1 month. Histologically, the cells enhanced skin thickness and skin vascularization. Moreover, expression of vascular endothelial growth factor, basic fibroblast growth factor, and hepatocyte growth factor also increased in the stromal vascular fraction group.

CONCLUSION

Autologous stromal vascular fraction cell transplantation enhances angiogenesis after skin grafting and improves the texture and elasticity of skin grafts.

A Bilayer Engineered Skin Substitute for Wound Repair in an Irradiation-Impeded Healing Model on Rat

Objective: An engineered skin substitute is produced to accelerate wound healing by increasing the mechanical strength of the skin wound via high production of collagen bundles. During the remodeling stage of wound healing, collagen deposition is the most important event. The collagen deposition process may be altered by nutritional deficiency, diabetes mellitus, microbial infection, or radiation exposure, leading to impaired healing. This study describes the fabrication of an engineered bilayer skin substitute and evaluates its effectiveness for the production of collagen bundles in an impaired healing model. Approach: Rats were exposed to 10 Gy of radiation. Two months postirradiation, the wounds were excised and treated with one of three skin replacement products: bilayer engineered skin substitutes, chitosan skin templates, or duoderm^©. The collagen deposition was analyzed by hematoxylin and eosin staining. Results: On day 21 postwound, the irradiated wounds displayed increased collagen bundle deposition after treatment using bilayer engineered skin substitutes (3.4±0.25) and chitosan skin templates (3.2±0.58) compared with duoderm (2.0±0.63). Innovation: We provide the first report on the fabrication of bilayer engineered skin substitutes using high density human dermal fibroblasts cocultured with HFSCs on chitosan skin templates. Conclusion: The high density of fibroblasts significantly increases the penetration of cells into chitosan skin templates, contributing to the fabrication of bilayer engineered skin substitute.

Primary chicken embryo fibroblasts seeded acellular dermal matrix (3-D ADM) improve regeneration of full thickness skin wounds in rats

Rat skins were deepithelialized and decellularized by hypertonic saline and sodium deoxycholate (SDC), respectively. Primary chicken embryo fibroblasts (P-CEF) were cultured and seeded on prepared acellular dermal matrix (ADM). A full thickness skin defect (20×20 mm(2)) was created in thirty-six rats and randomly divided into three equal groups. Defect was left open, repaired with ADM and ADM seeded with P-CEF (3-D ADM) in groups 1, 2 and 3, respectively. By day 28, the treated wounds healed completely without scar. By day 7 hydroxyproline contents was higher in group 3 as compared to groups 1 and 2. There was slightly more B cell response in animals implanted with ADM and 3-D ADM. At day 21, stimulation index was lower with acellular dermis antigen as compared to 3-D ADM antigen. In group 1 on day 3, the granulation tissue showed more inflammatory reaction, fibroplasia and neovascularization as compared to group 2 and 3. By day 28, there was complete epithelization was observed in all groups over. However, a large scar was observed in group 1. The graft was completely absorbed and replaced with densely thick and best arranged collagen fibers. On day 7, malonyldialdehyde and superoxide dismutase levels were significantly (P<0.05) increased in group 1. Reduced glutathione values increased and reached to near normal in groups 2 and 3. Catalase values were significantly (P<0.05) higher in group 1 at different time intervals. SEM samples of group 2 showed ingrowth of fibroblasts into acellular matrix at host graft junction. However, in group 3 fibroblasts were infiltrated within the pores of graft. It was concluded that P-CEF cells seeded ADM facilitated early and better healing.

Allogenous skin fibroblast transplantation enhances excisional wound healing following alloxan diabetes in sheep, a randomized controlled trial

BACKGROUND

Healing of skin wound is a multi-factorial and complex process. Treatment of diabetic wounds is still a major clinical challenge. Recently, stem cell transplantation to chronic wounds is favored. The objective of this study was to evaluate effects of pre-labeled allogenous skin fibroblasts on healing of ovine diabetic wound model.

METHODS

Eight 4-month-old Iranian Makoui wethers were used in this study. Alloxan monohydrate was used for induction of diabetes. In each wether two excisional wound were created on dorsum of the animal. Wounds of one side were randomly chosen as treatment group (n = 8), and wounds of the other side were considered as control group (n = 8). Pre-labeled skin fibroblasts with bromodeoxyuridine were used in wounds of one side as treatment. Photographs were taken in distinct times for planimetric evaluation. Wound samples were taken for BrdU detection and histopathologic evaluations on day 21 post-wounding.

RESULTS

The planimetric study showed closure of fibroblast treated wounds is significantly faster than control group (P < 0.05). Immunohistochemical staining with anti-bromodeoxyuridine antibody indicated presence of transplanted cells in the wounds. Histopathologic evaluations of H&E stained sections disclosed significantly increasing of re-epithelialization, number of fibroblasts, and number of blood vessels in treatment group in comparison to control group (P < 0.05).

CONCLUSION

[corrected] The results of this study indicated that allogenous skin fibroblast transplantation can positively affect wound healing in diabetic sheep.