Skin grafting with the modified Meek technique in the standing horse using full thickness skin: Evaluation of acceptance, wound contraction and wound closure in chronic wounds

BACKGROUND

The modified Meek technique is not commonly used in equine wound management, despite the consistent reliable and superior results compared with other grafting techniques. Major drawbacks are the need for specialised, expensive equipment and general anaesthesia.

OBJECTIVES

To describe adjustments of the modified Meek technique enabling use in the standing horse without the need for the full equipment. This implied the use of full-thickness skin grafts manually harvested from the pectoral area and manually cut into micrografts. Graft acceptance; healing progress; and final functional and cosmetic result were outcome parameters.

STUDY DESIGN

Descriptive case series.

METHODS

Eight horses with traumatic wounds at the dorsal side of the carpus or tarsus, healing by second intention, were treated. Original wound areas and areas of graft acceptance and rejection were determined from post-processing of digital photographs and percentage acceptance, wound contraction and epithelialisation were calculated.

RESULTS

The initial mean wound area was 55.4 cm2 . Graft acceptance was 95.3 ± 2.5%. Wound closure was due to 46.0 ± 25.6% wound contraction and 54.0 ± 25.6% epithelialisation and resulted in 96.8 ± 1.9% reduction of the initial wound area 28.0 ± 8.5 days after grafting. The scar was flat, flexible and functional, usually with thin and regular hair growth. The adapted procedure was fast and efficient, with a learning curve for the increased manual work.

MAIN LIMITATIONS

Small study population.

CONCLUSIONS

This adapted modified Meek technique can successfully be performed in the standing horse and obviates the need for the full expensive equipment and general anaesthesia. The acceptance of the full-thickness grafts is excellent resulting in fast and satisfactory healing.

Fragmented Dermo-Epidermal Units (FdeU) as an Emerging Strategy to Improve Wound Healing Process: An In Vitro Evaluation and a Pilot Clinical Study

Innovative strategies have shown beneficial effects in healing wound management involving, however, a time-consuming and arduous process in clinical contexts. Micro-fragmented skin tissue acts as a slow-released natural scaffold and continuously delivers growth factors, and much other modulatory information, into the microenvironment surrounding damaged wounds by a paracrine function on the resident cells which supports the regenerative process. In this study, in vitro and in vivo investigations were conducted to ascertain improved effectiveness and velocity of the wound healing process with the application of fragmented dermo-epidermal units (FdeU), acquired via a novel medical device (Hy-Tissue® Micrograft Technology). MTT test; LDH test; ELISA for growth factor investigation (IL) IL-2, IL-6, IL-7 IL-8, IL-10; IGF-1; adiponectin; Fibroblast Growth Factor (FGF); Vascular Endothelial Growth Factor (VEGF); and Tumor Necrosis Factor (TNF) were assessed. Therefore, clinical evaluation in 11 patients affected by Chronic Wounds (CW) and treated with FdeU were investigated. Functional outcome was assessed pre-operatory, 2 months after treatment (T0), and 6 months after treatment (T1) using the Wound Bed Score (WBS) and Vancouver Scar Scale (VSS). In this current study, we demonstrate the potential of resident cells to proliferate from the clusters of FdeU seeded in a monolayer that efficiently propagate the chronic wound. Furthermore, in this study we report how the discharge of trophic/reparative proteins are able to mediate the in vitro paracrine function of proliferation, migration, and contraction rate in fibroblasts and keratinocytes. Our investigations recommend FdeU as a favorable tool in wound healing, displaying in vitro growth-promoting potential to enhance current therapeutic mechanisms.

A Histological Evaluation of Artificial Dermal Scaffold Used in Micrograft Treatment: A Case Study of Micrograft and NPWT Performed on a Postoperative Ulcer Formation after Tumor Resection

Background and Objectives: Wound healing (WH) is a complex natural process: the achieving of a proper WH with standard therapies sometimes is not fulfilled and it is often observed in aged and diabetic patients, leading to intractable ulcers. In recent years, autologous micrograft (AMG) therapies have become a new, effective, and affordable wound care strategy among both researchers and clinicians. In this study, a 72-year-old female patient underwent a combination of treatments using micrograft and negative pressure wound therapy (NPWT) on a postoperative skin ulcer after a benign tumor resection on the back with the aim to present an innovative method to treat skin ulceration using AMG combined with an artificial dermal scaffold and NPWT. Materials and Methods: A section of the artificial dermal scaffold, infused with micrografts, was sampled prior to transplant, and sections were collected postoperatively on days 3 and 7. Hematoxylin-eosin (HE) and immunohistochemical stains were employed for the evaluation of Cytokeratin AE1/AE3, desmin, and Factor VIII. Additionally, on postoperative day 3, NPWT dressing was evaluated using HE stains, as well. The resulting HE and immunostaining analysis revealed red blood cells and tissue fragments within the collagen layers of the artificial dermis prior to transplant. On postoperative day 3, collagen layers of the artificial dermis revealed red blood cells and neutrophils based on HE stains, and scattering of cytokeratin AE1/AE3-positive cells were detected by immunostaining. The HE stains on postoperative day 7 showed more red blood cells and neutrophils within the collagen layers of the artificial dermis than on day 3, an increase in cytokeratin AE1/AE3-positive cells, and tissue stained positively with desmin and Factor VIII. Results: Results suggest that the effects of both micrografts and migratory cells have likely accelerated the wound healing process. Furthermore, the NPWT dressing on day 3 showed almost no cells within the dressing. This indicated that restarting NPWT therapy immediately after micrograft transplant did not draw out cells within the scaffold. Conclusions: Micrograft treatment and NPWT may serve to be a useful combination therapy for complex processes of wound healing.

The Role of Adipose Tissue in Hair Regeneration: A Potential Tool for Management?

Human adipose tissue (AT) is a rich and easily harvestable source of stem cells and various growth factors (GFs). It has been widely used hitherto for facial rejuvenation and volumization. Increasing evidence shows that dermal adipocytes are intricately associated with hair follicles (HFs) and may be necessary to drive follicular stem cell activation. Early published data have shown encouraging preliminary results for the use of adipocytes and their stem cells as a treatment option for hair growth. The aim of this review study is to analyze published literature on the effect of fat on hair growth and to summarize the current evidence.

Surgical Strategies to Promote Cutaneous Healing

Usually, cutaneous wound healing does not get impeded and processes uneventfully, reaching wound closure easily. The goal of this repair process is to restore the integrity of the body surface by creating a resilient and stable scar. Surgical practice and strategies have an impact on the course of wound healing and the later appearance of the scar. By considering elementary surgical principles, such as the appropriate suture material, suture technique, and timing, optimal conditions for wound healing can be created. Wounds can be differentiated into clean wounds, clean–contaminated wounds, contaminated, and infected/dirty wounds, based on the degree of colonization or infection. Furthermore, a distinction is made between acute and chronic wounds. The latter are wounds that persist for longer than 4–6 weeks. Care should be taken to avoid surgical site infections in the management of wounds by maintaining sterile working conditions, using antimicrobial working techniques, and implementing the principles of preoperative antibiotics. Successful wound closure is influenced by wound debridement. Wound debridement removes necrotic tissue, senescent and non-migratory cells, bacteria, and foreign bodies that impede wound healing. Additionally, the reconstructive ladder is a viable and partially overlapping treatment algorithm in plastic surgery to achieve successful wound closure.

Novel application of autologous micrografts in a collagen-glycosaminoglycan scaffold for diabetic wound healing

BACKGROUND

Therapeutic strategies that successfully combine two techniques-autologous micrografting and biodegradable scaffolds-offer great potential for improved wound repair and decreased scarring. In this study we evaluate the efficacy of a novel modification of a collagen-glycosaminoglycan scaffold with autologous micrografts using a murine dorsal wound model.

METHODS

db/db mice underwent dorsal wound excision and were treated with a collagen-glycosaminoglycan scaffold (CGS), a modified collagen-glycosaminoglycan scaffold (CGS+MG) or simple occlusive dressing (Blank). The modified scaffold was created by harvesting full thickness micrografts and transplanting these into the collagen-glycosaminoglycan membrane. Parameters of wound healing, including cellular proliferation, collagen deposition, keratinocyte migration, and angiogenesis were assessed.

RESULTS

The group treated with the micrograft-modified scaffold healed at a faster rate, showed greater cellular proliferation, collagen deposition, and keratinocyte migration with higher density and greater maturity of microvessels. The grafts remained viable within the scaffold with no evidence of rejection. Keratinocytes were shown to migrate from the wound border and from the micrograft edges towards the center of the wound, while cellular proliferation was present both at the wound border and wound bed.

CONCLUSION

We report successful treatment of diabetic wounds with a novel collagen-glycosaminoglycan scaffold modified with full-thickness automicrografts. Differences in cellular migration and proliferation offer maiden evidence on the mechanisms of wound healing. Clinically, the successful scaffold engraftment, micrograft viability and improved wound healing offer promising results for the development of a new therapeutic modality for wound repair.

Acceleration of Skin Wound-Healing Reactions by Autologous Micrograft Tissue Suspension

Background and objectives: Skin grafting is a method usually used in reconstructive surgery to accelerate skin regeneration. This method results frequently in unexpected scar formations. We previously showed that cutaneous wound-healing in normal mice is accelerated by a micrograft (MG) technique. Presently, clinical trials have been performed utilizing this technology; however, the driving mechanisms behind the beneficial effects of this approach remain unclear. In the present study, we focused on five major tissue reactions in wound-healing, namely, regeneration, migration, granulation, neovascularization and contraction. Methods: Morphometrical analysis was performed using tissue samples from the dorsal wounds of mice. Granulation tissue formation, neovascularization and epithelial healing were examined. Results: The wound area correlated well with granulation sizes and neovascularization densities in the granulation tissue. Vascular distribution analysis in the granulation tissue indicated that neovessels extended and reached the subepidermal area in the MG group but was only halfway developed in the control group. Moreover, epithelialization with regeneration and migration was augmented by MG. Myofibroblast is a known machinery for wound contraction that uses α-smooth muscle actin filaments. Their distribution in the granulation tissue was primarily found beneath the regenerated epithelium and was significantly progressed in the MG group. Conclusions: These findings indicated that MG accelerated a series of wound-healing reactions and could be useful for treating intractable wounds in clinical situations.

Free skin micrografts with cyanoacrylate as outpatient treatment for venous leg ulcers

OBJECTIVE

The present study describes an ambulatory, free skin micrograft technique with cyanoacrylate as a coadjuvant venous leg ulcer (VLU) healing strategy and its outcomes after one month.

METHODS

This prospective study involved Comprehensive Classification System for Chronic Venous Disorders (CEAP) stage C6 patients with good granulation tissue and negative culture results, consecutively recruited in January 2017 in the Hospital Clinico San Carlos. A skin micrograft was harvested from the anterior surface of the patient's thigh with a 0.4cm punch (0.12cm²). The graft was adhered to the ulcer bed with cyanoacrylate. Anti-adherent dressing and double-layer bandaging was applied, with weekly replacements. Measurements were obtained of the surface of the VLU and graft progression (in cm²) using a photographic grid.

RESULTS

A total of 12 VLUs in 12 patients were included, with a mean treated surface of 20.32±13.9cm². A total of 18 grafts were placed and all were found to be viable after one week. Average graft growth was not noticeable after one week but was found to be 0.25±0.08cm² after week two, 0.41±0.98cm² after week three, and 0.70±0.15cm² after week four (p<0.001). There were no complications in the donor zone.

CONCLUSION

The findings of this study show that free skin micrografting with cyanoacrylate as outpatient treatment for VLUs was simple, rapid and without complication in this study, and may contribute to its wider application in clinical use.

Progenitor-cell-enriched micrografts as a novel option for the management of androgenetic alopecia

Regenerative medicine is a multidisciplinary field that combines engineering and life science principles to promote regeneration, potentially restoring the physiological condition in diseased tissues. Specifically, the developments of complex grafts enhance the intrinsic regenerative capacity of the host by altering its environment. Autologous micrografts obtained through Rigenera® micrografting technology are able to promote derma and bone regeneration. Androgenetic alopecia (AGA) leads to a progressive thinning of scalp hair affecting 60-70% of the adult population worldwide. Pharmacological treatment offers moderate results and hair transplantation represents the only permanent treatment option. The aim of this study was to demonstrate the role of dermis micrografting in the treatment of AGA by clinical and histological evaluations after 4, 6, and 12 months. Hair growth and density were improved at all indicated times. Those outcomes were also confirmed by the TrichoScan® analysis, reporting an increase of total hair count and density with an increase and reduction of anagen and telogen phases, respectively. Scalp dermoscopic analysis showed an improvement of hair density and histological analysis indicated a clear amelioration of the scalp, development of hair follicles, and a beginning of cuticle formation. Collectively, those results suggest a possible use of the micrografts as a novel therapeutic option in the management of AGA.

Progress report for intractable ulcer and osteomyelitis cases using autologous micrografts

Intractable ulcers often occur following primary diseases and have a significant impact on the quality of life of affected subjects. The medical treatments now available include compression and continuous debridement or additional interventions such as advanced wound dressings, local or systemic antibiotics with a mild benefit for the patients in the long term. In this report, we describe the use of autologous micrografts obtained by Rigenera^® procedure in the management of two cases of intractable ulcers showing good outcomes for both patients approximately after 30 days from intervention. In the first case, a 74-year-old male with a diagnosis of Fournier's gangrene who underwent several interventions showed a rapid wound epithelization after micrografts application. In the second case, a 63-year-old male affected by a left hallux ulcer with a diagnosis of chronic osteomyelitis also showed a gradual reduction in the ulcer approximately after 1 month from micrografts application.

Acceleration Mechanisms of Skin Wound Healing by Autologous Micrograft in Mice

A micrograft technique, which minces tissue into micro-fragments >50 μm, has been recently developed. However, its pathophysiological mechanisms in wound healing are unclear yet. We thus performed a wound healing study using normal mice. A humanized mouse model of a skin wound with a splint was used. After total skin excision, tissue micro-fragments obtained by the Rigenera protocol were infused onto the wounds. In the cell tracing study, GFP-expressing green mice and SCID mice were used. Collagen stains including Picrosirius red (PSR) and immunohistological stains for α-smooth muscle actin (αSMA), CD31, transforming growth factor-β1 (TGF-β1) and neutrophils were evaluated for granulation tissue development. GFP-positive cells remained in granulation tissue seven days after infusion, but vanished after 13 days. Following the infusion of the tissue micrograft solution onto the wound, TGF-β1 expression was transiently upregulated in granulation tissue in the early phase. Subsequently, αSMA-expressing myofibroblasts increased in number in thickened granulation tissue with acceleration of neovascularization and collagen matrix maturation. On such granulation tissue, regenerative epithelial healing progressed, resulting in wound area reduction. Alternative alteration after the micrograft may have increased αSMA-expressing myofibroblasts in granulation tissue, which may act on collagen accumulation, neovascularization and wound contraction. All of these changes are favorable for epithelial regeneration on wound.

Fast and Standardized Skin Grafting of Leg Wounds With a New Technique: Report of 2 Cases and Review of Previous Methods

BACKGROUND

Chronic leg ulcers remain a challenge to the treating physician. Such wounds often need skin grafts to heal. This necessitates a readily available, fast, simple, and standardized procedure for grafting.

OBJECTIVES

The aim of this work was to test a novel method developed for outpatient transplant procedures.

METHODS

The procedure employs a handheld disposable dermatome and a roller mincer that cut the skin into standardized micrografts that can be spread out onto a suitable graft bed. Wounds were followed until healed and photographed.

RESULTS

The device was successfully used to treat and close a traumatic lower limb wound and a persistent chronic venous leg ulcer. The donor site itself healed by secondary intent with minimal cosmetic impairment.

CONCLUSION

The method was successfully used to graft 2 lower extremity wounds.