A primer on pigmentation

Scar changes over time after artificial dermis grafting for full-thickness temporal defects following skin cancer excision: A colorimetric and anthropometric study

Advances in biotechnology have introduced artificial dermis as an alternative to autologous tissue reconstruction. Our group has employed artificial dermis grafting for full-thickness temporal defects to overcome the limitations of traditional reconstructive methods, such as local flaps and skin grafts. This study evaluates the changes in colour matching and the degree of scar contraction following artificial dermis grafting and explores its potential for reconstructing such defects. This retrospective study included 25 patients who underwent artificial dermis grafting after skin cancer excision in the temporal region. Colour differences between the scar and surrounding skin were quantified using dE2000 scores. Scar contraction was assessed by measuring scar areas. These two parameters were evaluated intraoperatively, immediately after wound healing, and at 3, 6, and 12 months post-healing. The dE2000 scores immediately after healing and at 3, 6, and 12 months were 15.4 ± 7.4, 14.9 ± 6.8, 10.4 ± 4.6, and 6.3 ± 2.0, respectively (p < 0.01). According to reference values, the colour mismatch was rated as "fair" until 6 months post-healing and as "very good" at 12 months. The amounts of scar contraction immediately after healing and at 3, 6, and 12 months were 55.3 ± 10.5%, 65.6 ± 8.6%, 32.5 ± 15.9%, and 20.6 ± 14.8%, respectively (p < 0.01). These findings indicate that artificial dermis grafting for full-thickness temporal defects initially leads to significant colour mismatch and scar contraction. However, both parameters improve over time, achieving favourable outcomes within 12 months. Artificial dermis grafting may be a viable option for reconstructing skin and soft tissue defects in the temporal region.

Comparison of Tissue-Engineered Dermis with Micronized Adipose Tissue and Artificial Dermis for Facial Reconstruction Following Skin Cancer Resection

Our group has previously demonstrated that tissue-engineered dermis containing cultured fibroblasts or adipose-derived stromal vascular fraction cells is superior to artificial dermis in terms of scar quality for covering facial defects. However, using these cells for clinical applications requires Food and Drug Administration approval and involves complex procedures for cell culture or isolation. This retrospective study aimed to compare effects of tissue-engineered dermis containing micronized adipose tissue (MAT) and artificial dermis for facial reconstruction. Tissue-engineered dermis consisting of MAT seeded on artificial dermis was applied in 30 cases, while artificial dermis without MAT was grafted in 35 cases. Healing time and severities of scar contraction, color mismatch, and landmark distortion at one year after healing were evaluated. Wounds in the tissue-engineered dermis group re-epithelialized in 30.0 ± 4.3 days compared to 34.3 ± 5.4 days in the artificial dermis group (p < 0.05). The average dE2000 score in color mismatch analysis was 4.9 ± 1.7 in the tissue-engineered dermis group and 5.1 ± 1.7 in the artificial dermis group (p = 0.57). The extent of scar contraction was 16.2 ± 12.3% in the tissue-engineered dermis group and 23.2 ± 12.8% in the artificial dermis group (p < 0.05). The average severity grade of landmark distortion was 0.20 ± 0.50 in the tissue-engineered dermis group and 0.50 ± 0.71 in the artificial dermis group (p < 0.05). These findings indicate that tissue-engineered dermis grafts containing MAT are superior to artificial dermis grafts for facial reconstruction in terms of healing time, scar contraction, and landmark distortion severity. However, there was no significant difference in color mismatch between the two groups.

Irritant Contact Dermatitis Due to Fecal, Urinary, or Dual Incontinence: It Is Time to Focus on Darkly Pigmented Skin

GENERAL PURPOSE

To review best practices related to the assessment of irritant contact dermatitis due to fecal, urinary, or dual incontinence (ICD-FIUIDI) among patients with darkly pigmented skin.

TARGET AUDIENCE

This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and registered nurses with an interest in skin and wound care.

LEARNING OBJECTIVES/OUTCOMES

After participating in this educational activity, the participant will:1. Identify risk factors for the development of ICD-FIUIDI.2. Describe clinical features and manifestations of ICD-FIUIDI.3. Propose recommendations to improve care related to ICD-FIUIDI.

Management of the Sequelae of Skin Grafting: Pruritis, Folliculitis, Pigmentation Changes, and More

Scars commonly give rise to unpredictable, potentially irritating, cutaneous complications including pruritis, folliculitis, and pigment changes. These problems can be self-limiting and are prevalent in many burn cases, although their expression varies among individuals. A better understanding of the presentation, risk factors, and pathophysiology of these long-term sequelae allows for more comprehensive care of burn survivors.

Nonsurgical Treatment of Postburn Hypopigmentation: A Literature Review

The treatment of postburn hypopigmentation was primarily surgical before the advent of new technologies. Medical devices and therapies are emerging to manage scar sequelae that can be disfiguring and associated with severe psychosocial impact. These innovations have been poorly investigated for hypopigmentation, but they represent a real hope. We reviewed all articles published on Pubmed up to June 2022. Included studies had to specifically focus on treating postburn hypopigmented scars. All articles evaluating transient solutions such as make-up, and articles describing inflammation-linked hypopigmentation with no etiological details or no burn injury history were excluded. Through this review, we have highlighted 6 different types of nonsurgical treatments reported in postburn leukoderma potentially allowing definitive results. Electrophoto-biomodulation or E light (combining intensive pulsed light, radiofrequency, and cooling), topical daylight psoralen UVA therapy, and lasers (fractional lasers using pulse energies or CO2FL devices, lasers-assisted drug delivery as local bimatoprost and tretinoin or pimecrolimus) have been explored with encouraging results in hypopigmented burns. Finally, other promising medical strategies include using FK506, a nonsteroidal anti-inflammatory drug, to induce melanogenesis or using melanocyte-stimulating hormones with fractional laser-assisted drug deliveries, which are expected to emerge soon.

Young Chinese female body skin pigmentation map: A pilot study

BACKGROUND

Most studies have discussed variations in facial skin colour based on age, gender, and anatomical site within a specific ethnic group. However, skin pigmentation on the body is also a concern for many people.

AIM

The aim of this study is to gather baseline data for Chinese young females, conduct a comprehensive assessment of body skin pigmentation, and create a body skin pigmentation map.

METHOD

Individual type angle (ITA°) was registered by CL 400 and melanin index (MI) was registered by MX 18 in 100 body points of 20 Chinese females. A total of 12,000 measurements were recorded.

RESULT

Our results showed significant differences among the symmetrical points on both sides of the body, including the clavicle, inner wrists, groin, inner ankle, elbow, armpit, waist side, the space between the thumb and index finger, instep, back shoulder, and popliteal space. Of all the points tested on the body, the points with the most severe skin pigmentation were the back of the neck, the heel, the elbow, and the popliteal space.

CONCLUSION

This is the first comprehensive study of skin pigmentation conducted on the human body. In young Chinese women, the points with the most severe skin pigmentation were the back of the neck, heels, elbows, and the popliteal space.

Operative Management of Burns: Traditional Care

Surgical treatment of burn wounds has had a tremendous impact on burn patients. The survival of patients with massive burns is now very common. Expeditious coverage of the wound has been a major contributor to improved survival, but survival is not enough. There is a need to improve the ultimate functional and cosmetic outcomes of the wound in order to facilitate a patient's return to society. This paper reviews strategies, using fairly basic techniques, to optimize the outcomes of burn patients. While there are many new skin products available, the strategies presented here can apply to any surgeon treating burns throughout the entire world.

Sustainable Approach of Functional Biomaterials-Tissue Engineering for Skin Burn Treatment: A Comprehensive Review

Burns are a widespread global public health traumatic injury affecting many people worldwide. Non-fatal burn injuries are a leading cause of morbidity, resulting in prolonged hospitalization, disfigurement, and disability, often with resulting stigma and rejection. The treatment of burns is aimed at controlling pain, removing dead tissue, preventing infection, reducing scarring risk, and tissue regeneration. Traditional burn wound treatment methods include the use of synthetic materials such as petroleum-based ointments and plastic films. However, these materials can be associated with negative environmental impacts and may not be biocompatible with the human body. Tissue engineering has emerged as a promising approach to treating burns, and sustainable biomaterials have been developed as an alternative treatment option. Green biomaterials such as collagen, cellulose, chitosan, and others are biocompatible, biodegradable, environment-friendly, and cost-effective, which reduces the environmental impact of their production and disposal. They are effective in promoting wound healing and reducing the risk of infection and have other benefits such as reducing inflammation and promoting angiogenesis. This comprehensive review focuses on the use of multifunctional green biomaterials that have the potential to revolutionize the way we treat skin burns, promoting faster and more efficient healing while minimizing scarring and tissue damage.

[Buried chipped skin grafts for patients in failure of treatment]

Local conditions can lead to a failure of traditional skin grafts. We propose here our technique about the realization of autologous skin graft using it buried chipped grafts, for wounds in failure of treatments or at risk of failure. The protocol includes cutting the skin graft within little squared pieces of a few millimeters of length, that are then buried directly deep into the wound. We can then obtain little islands of epidermisation on the random places of the wound that will heal by confluence of those epidermal islands.

Treatment of hyperpigmentation after burn: A literature review

OBJECTIFY

Skin pigmentation disorders are one of the most frequent sequelae after burn injury. While these conditions often improve over time, some are permanent and cause severe psychological disorders (especially on the face). Given the frequency of these disorders and their benign nature, the scientific community has great difficulty postponing these patient follow-ups. Publications on their management are rare, and there is no consensus on the gold standard treatment for skin dyschromia. Herein, we performed a literature review including the various treatments currently proposed to manage these hyperpigmentations.

METHODS

All reported articles up to February 2021 were reviewed on Pubmed. Studies on the treatment of hyperpigmented scars were included if they were secondary to burn injuries. Excluded articles evaluated transient treatments, such as makeup, and articles on inflammatory hyperpigmentation without etiological details or not secondary to burns.

RESULTS

201 articles were identified, and 13 studies were included. Topical creams used in inflammatory hyperpigmented lesions such as hydroquinone and first-line retinoids are controversial due to their inconstant efficacy. Various types of laser and pulsed light treatments have shown their effectiveness but can also aggravate pigmentation.

CONCLUSION

Dyschromia after burn remains a therapeutic challenge. Hyperpigmentations after burn should be treated on a case-by-case basis, using data from the literature, clinical experience and measuring the risk/benefit ratio.

LncRNA XIST accelerates burn wound healing by promoting M2 macrophage polarization through targeting IL-33 via miR-19b

Burn injuries are a serious threat to quality of life. The aim of this study was to investigate the mechanism of burn wound healing. The lncRNA XIST has been associated with burn wound healing, but the mechanism is not clear. In the present study, in vitro and in vivo models of burn injuries were established by thermal injury treatment of human skin fibroblasts (HSFs) and mice, respectively. Pathological changes in skin tissues were detected by haematoxylin and eosin (HE) staining. Immunofluorescence double staining was performed to detect M2 macrophages. Furthermore, the changes of cell proliferation, apoptosis and migration by CCK-8, flow cytometry, scratch and Transwell assays to evaluate the effect of XIST on burn wound healing. The binding relationships among XIST, miR-19b and IL-33 were analyzed by RNA immunoprecipitation (RIP) and dual luciferase reporter assays. Our results found that there were targeted binding sites between XIST and miR-19b, miR-19b and IL-33. We investigated whether XIST enhanced the polarization of M2 macrophages to promote the healing of burn wounds. After fibroblast burn injury, the expression levels of XIST and IL-33 increased in a time-dependent manner, whereas miR-19b expression decreased in a time-dependent manner. XIST contributed to the proliferation and migration of skin fibroblasts by inhibiting miR-19b and enhanced fibroblast extracellular matrix production by promoting the transformation of macrophages to the M2 phenotype. In short, these findings indicate that XIST can promote burn wound healing and enhance the polarization of M2 macrophages by targeting the IL-33/miR-19b axis, which may serve as a potential theoretical basis for the treatment of burn wound healing.

Laser Treatment of Hypopigmentation in Scars: A Review

BACKGROUND

Despite history of multiple treatment modalities, repigmentation of hypopigmented scars remains a difficult clinical problem.

OBJECTIVE

The purpose of this review is to evaluate the literature on laser and combination laser plus adjunct topical therapy for hypopigmented burn and traumatic scars.

MATERIALS AND METHODS

A search on PubMed and on Oxford Academic was conducted with additional relevant literature obtained from reference lists.

RESULTS

Treatment regimens that address hypopigmentation within scars were reviewed. A combination of nonablative fractional or ablative fractional laser treatment with topical prostaglandin analogue with or without topical retinoid were found to result in superior repigmentation.

CONCLUSION

Reliable improvement of hypopigmentation in scars after laser treatment is challenging. Laser can achieve success in some cases. Ultraviolet laser can achieve modest repigmentation; however, results are short-lived and require continued re-treatment. Modest improvement in pigmentation is seen with nonablative fractional laser or ablative fractional laser alone and enhanced repigmentation is demonstrated when combining fractional laser resurfacing with topical application of synthetic prostaglandin analogues and other known modulators of melanogenesis.

Hypopigmented burn hypertrophic scar contains melanocytes that can be signaled to re-pigment by synthetic alpha-melanocyte stimulating hormone in vitro

There are limited treatments for dyschromia in burn hypertrophic scars (HTSs). Initial work in Duroc pig models showed that regions of scar that are light or dark have equal numbers of melanocytes. This study aims to confirm melanocyte presence in regions of hypo- and hyper-pigmentation in an animal model and patient samples. In a Duroc pig model, melanocyte presence was confirmed using en face staining. Patients with dyschromic HTSs had demographic, injury details, and melanin indices collected. Punch biopsies were taken of regions of hyper-, hypo-, or normally pigmented scar and skin. Biopsies were processed to obtain epidermal sheets (ESs). A subset of ESs were en face stained with melanocyte marker, S100β. Melanocytes were isolated from a different subset. Melanocytes were treated with NDP α-MSH, a pigmentation stimulator. mRNA was isolated from cells, and was used to evaluate gene expression of melanin-synthetic genes. In patient and pig scars, regions of hyper-, hypo-, and normal pigmentation had significantly different melanin indices. S100β en face staining showed that regions of hyper- and hypo-pigmentation contained the same number of melanocytes, but these cells had different dendricity/activity. Treatment of hypo-pigmented melanocytes with NDP α-MSH produced melanin by microscopy. Melanin-synthetic genes were upregulated in treated cells over controls. While traditionally it may be thought that hypopigmented regions of burn HTS display this phenotype because of the absence of pigment-producing cells, these data show that inactive melanocytes are present in these scar regions. By treating with a pigment stimulator, cells can be induced to re-pigment.

Chemical eye injury: pathophysiology, assessment and management

Chemical eye injury (CEI) is an acute emergency which can threaten sight and life. These commonly occur at home or the workplace with the former being generally mild and the latter more severe and bilateral. Major workplace accidents involve other parts of the body and can be associated with inhalation or ingestion of the chemical. Alkali injuries cause damage by saponification of tissue and deeper penetration as a consequence. Acid injuries cause rapid coagulation of tissue, which impedes penetration and limits damage. Irritants such as alcohols, cause superficial epithelial denudation. Severe chemical insult can affect all anterior segment structures causing iris, pupil and lens abnormalities. Eye pressure is variably affected and can be low or high or start as one and rapidly change to the other. Chorioretinal changes in the form of vasculopathy are seen and ascribed to be secondary to anterior segment inflammation rather than due to the direct effect of CEI. Final outcome related to structure and function is determined by the injurious agent, duration of exposure, nature of treatment and the rapidity with which it is instituted. Prevention of further damage by profuse and prolonged eye wash, after ascertaining pH of both eyes, together with exploration and removal of all particulate matter, is the key. Other management principles include a complete and thorough assessment, control of inflammation, facilitation of healing and prevention and management of sequelae and complications. Intraocular pressure is often forgotten and must be assessed and managed. Management often requires a multidisciplinary approach.

A Systematic Review on Classification, Identification, and Healing Process of Burn Wound Healing

Because of the intrinsic complexity, the classification of wounds is important for the diagnosis, management, and choosing the correct treatment based on wound type. Generally, burn injuries are classified as a class of wounds in which injury is caused by heat, cold, electricity, chemicals, friction, or radiation. On the other hand, wound healing is a complex process, and understanding the biological trend of this process and differences in the healing process of different wounds could reduce the possible risk in many cases and greatly reduce the future damage to the injured tissue and other organs. The aim of this review is to provide a general perspective for the burn wound location among the other types of injuries and summarizing as well as highlighting the differences of these types of wounds with emphasizing on factors affecting thereof.

Light or Dark Pigmentation of Engineered Skin Substitutes Containing Melanocytes Protects Against Ultraviolet Light-Induced DNA Damage In Vivo

Engineered skin substitutes (ESS) containing autologous fibroblasts and keratinocytes provide stable wound closure in patients with large, full-thickness burns, but are limited by hypopigmentation due to absence of added melanocytes. DNA damage caused by ultraviolet radiation (UV) increases risk for skin cancer development. In human skin, melanocytes provide pigmentation that protects skin from UV-induced DNA damage. This study investigated whether inclusion of human melanocytes (hM) affects the response of ESS to UV in vivo. Specifically, pigmentation and formation of cyclobutane pyrimidine dimers (CPDs), the most prevalent UV-induced DNA photoproduct, were analyzed. Three groups of ESS were prepared with fibroblasts and keratinocytes, ± melanocytes, and grafted orthotopically to immunodeficient mice: ESS without melanocytes (ESS-hM), ESS with light skin-derived (Caucasian) melanocytes (ESS+hM-L), and ESS with dark skin-derived (African-American) melanocytes (ESS+hM-D). Pigmentation of ESS+hM-L and ESS+hM-D increased significantly after grafting; pigmentation levels were significantly different among groups. Mean melanocyte densities in ESS+hM-L and ESS+hM-D were similar to each other and to densities in normal human skin. After 8 weeks in vivo, grafts were irradiated with 135 mJ/cm2 UV; non-UV-treated mice served as controls. UV modestly increased pigmentation in the ESS+hM groups. UV significantly increased CPD levels in ESS-hM, and levels in ESS-hM were significantly greater than in ESS+hM-L or ESS+hM-D. The results demonstrate that light or dark melanocytes in ESS decreased UV-induced DNA damage. Therefore, melanocytes in ESS play a photoprotective role. Protection against UV-induced DNA damage is expected to reduce skin cancer risk in patients grafted with ESS containing autologous melanocytes.

The use of 4% hydroquinone, 0.1% tretinoin, and 0.1% betamethasone creams to prevent hyperpigmentation of split-thickness skin grafts in Long-Evans rats

BACKGROUND

The increase in the pigmentation of skin grafts during the healing process is a cosmetic problem. There are a variety of medical and surgical treatment options for skin graft darkening.

AIMS

The aim of this study was to investigate the effects of topical hydroquinone, tretinoin, and betamethasone application on hyperpigmentation of skin grafts.

METHODS

A skin defect was created on the backs of 17 Long-Evans rats, and a 2 × 2 cm split-thickness skin graft was sutured. After 15 days, eight rats in the treatment group were treated with application of hydroquinone, tretinoin, and betamethasone cream, while nine rats in the control group were not treated. Visual evaluation was performed on days 45 and 75 using the Melasma Severity Scale (MSS), and histological evaluation was performed on day 75 using S100 and Masson Fontana (MF) staining. The Mann-Whitney U test was used for statistical analysis.

RESULTS

Mean MSS values of the treatment group on days 45 were significantly lower compared to the control group (P = .036). On day 75, the mean MSS score of the treatment group was also lower; however, the difference was not statistically significant (P = .302). Histological evaluation of S100 and MF staining scores of the treatment group showed fewer melanocytes and fewer pigments in epidermis (P = .009 and P = .002, respectively).

CONCLUSIONS

This study showed that topical application of hydroquinone, tretinoin, and betamethasone reduced the hyperpigmentation, number of melanocytes, and melanin pigment intensity that developed on the rat skin graft models. Clinical studies are needed to assess whether a similar effect could be observed with human skin grafts.

Exogenous Keratinocyte Growth Factor Is Not Required for Pigmentation of Skin Substitutes with Three Isogeneic Cell Types

Engineered skin substitutes (ESS) containing human fibroblasts (hF) and human keratinocytes (hK) provide significant medical benefits for treatment of acute and chronic skin wounds, including, but not limited to, burns, burn scars, congenital skin lesions, and cutaneous ulcers. However, anatomic deficiencies, such as lack of pigment, can contribute to long-term morbidity, including hypopigmentation and reduced solar protection. To address the deficiency of hypopigmentation, ESS were populated sequentially with cultured hF, human melanocytes (hM), and hK to generate ESS with pigment (ESS-P). Constructs were incubated in media containing 0.0, 1.5, or 5.0 ng/mL keratinocyte growth factor (KGF), which promotes survival and differentiation of hM in ESS-P, and had media changed at 24 or 48 h intervals. ESS-P were evaluated in vitro for surface hydration, surface color, and distribution of hM. Proliferation was assessed by measuring incorporation of 5-bromo-2'-deoxyuridine into replicating DNA in basal epidermal cells. ESS-P from test conditions were grafted to immunodeficient mice, and were assessed over 12 weeks for pigmented area, pigment density, and distribution of hM in healed human grafts. The in vitro data showed differences among test groups, including increase in hydration of the epidermal surface with higher KGF, increase of surface pigmentation with 24 h media changes, increase of hM density with higher KGF and 24 h media changes, and time-dependent decrease of proliferation. At 12 weeks after grafting, differences among groups were found for pigment density, but not for distribution of hM or percentage of pigmented area. These differences demonstrate that a higher concentration of KGF (5 ng/mL) in the maturation medium of ESS-P and more frequent media changes (24 h interval) promote higher viability and hM differentiation of ESS-P before grafting, but are not required for full pigmentation (pigmented area, pigment density, hM distribution) of grafted wounds. Based on these results, reductions of the concentration of KGF (i.e., 1.5 ng/mL) in the maturation medium, and of the frequency of medium changes (48 h intervals) would be expected to support survival, continued replication, and restoration of skin color by hM in therapeutic transplantation of ESS-P. Impact Statement Restoration of skin color after traumatic injury affects personal identity and provides protection from exposure to solar radiation. Keratinocyte growth factor (KGF) and nutrient supply are known to regulate survival of melanocytes before transplantation in engineered skin substitutes with pigment (ESS-P). This report demonstrates that exogenous KGF is not required to restore skin color and that replacement of the nutrient medium at lower frequency (48 versus 24 h) does not inhibit development of skin color after melanocyte transplantation. These results offer new alternatives to conserve resources in fabrication of ESS-P and to maintain efficacy for restoration of skin color.

Acquired disorders with hypopigmentation: A clinical approach to diagnosis and treatment

Acquired hypopigmented skin changes are commonly encountered by dermatologists. Although hypopigmentation is often asymptomatic and benign, occasional serious and disabling conditions present with cutaneous hypopigmentation. A thorough history and physical examination, centered on disease distribution and morphologic findings, can aid in delineating the causes of acquired hypopigmented disorders. The second article in this 2-part continuing medical education series focuses on conditions with a hypopigmented phenotype. Early diagnosis and appropriate management of these disorders can improve a patient's quality of life, halt disease progression, and prevent irreversible disability.

Tissue engineering of skin and regenerative medicine for wound care

Engineering of biologic skin substitutes has progressed over time from individual applications of skin cells, or biopolymer scaffolds, to combinations of cells and scaffolds for treatment, healing, and closure of acute and chronic skin wounds. Skin substitutes may be categorized into three groups: acellular scaffolds, temporary substitutes containing allogeneic skin cells, and permanent substitutes containing autologous skin cells. Combined use of acellular dermal substitutes with permanent skin substitutes containing autologous cells has been shown to provide definitive wound closure in burns involving greater than 90% of the total body surface area. These advances have contributed to reduced morbidity and mortality from both acute and chronic wounds but, to date, have failed to replace all of the structures and functions of the skin. Among the remaining deficiencies in cellular or biologic skin substitutes are hypopigmentation, absence of stable vascular and lymphatic networks, absence of hair follicles, sebaceous and sweat glands, and incomplete innervation. Correction of these deficiencies depends on regulation of biologic pathways of embryonic and fetal development to restore the full anatomy and physiology of uninjured skin. Elucidation and integration of developmental biology into future models of biologic skin substitutes promises to restore complete anatomy and physiology, and further reduce morbidity from skin wounds and scar. This article offers a review of recent advances in skin cell thrapies and discusses the future prospects in cutaneous regeneration.

Treatment Strategies for Hypopigmentation in the Context of Burn Hypertrophic Scars

Dyspigmentation in burn scars can contribute to the development of psychosocial complications after injury and can be detrimental to social reintegration and quality of life for burn survivors. Although treatments for skin lightening to treat hyperpigmentation have been well reviewed in the literature, skin-darkening strategies to treat hypopigmentation have not. The following potential treatment options in the context of burn hypertrophic scar will be discussed: use of the melanocyte-keratinocyte transplantation procedure, use of ectopic synthetic analogues of alpha-melanocyte stimulating hormone to initiate melanogenesis, and use of FK506 to induce melanogenesis. A proposed future direction of research in laser-assisted drug delivery of inducers of local melanin production, with the hope of developing a targeted, effective approach to dyspigmentation in hypertrophic scar is also discussed.

Autologous adipose-derived regenerative cell therapy modulates development of hypertrophic scarring in a red Duroc porcine model

Background

Effective prevention and treatment of hypertrophic scars (HTSs), a common consequence of deep-partial thickness injury, remain a significant clinical challenge. Previous studies from our group have shown that autologous adipose-derived regenerative cells (ADRCs) represent a promising approach to improve wound healing and, thereby, impact HTS development. The purpose of this study was to assess the influence of local delivery of ADRCs immediately following deep-partial thickness cutaneous injury on HTS development in the red Duroc (RD) porcine model.

Methods

Bilateral pairs of deep-partial thickness excisional wounds (2 mm depth; 58 cm² area) were created using an electric dermatome on RD pigs (n = 12). Autologous ADRCs were isolated from the inguinal fat pad and then sprayed directly onto the wound at a dose of 0.25 × 10⁶ viable cells/cm². The paired contralateral wound received vehicle control. Wound healing and development of HTS were assessed over 6 months using digital imaging, quantitative measurement of skin hardness and pigmentation, and histology.

Results

Data showed that ADRC treatment led to reduced scar hyperpigmentation compared to control (p < 0.05). Using the Durometer, at 2 and 6 months post-injury, skin hardness was 10–20% lower in ADRCs-treated wounds compared to control vehicle (p < 0.05). A similar trend was observed with the skin fibrometer.

ADRC treatment promoted more normal collagen organization, improvement in the number of rete ridges (p < 0.01), longer elastic fiber length (p < 0.01), and reduced hypervascularity (blood vessel density; p < 0.05). ADRC treatment was associated with modulation of IL-6 expression within the wound/scar with upregulation 2 weeks after injury (wound healing phase) and downregulation at 2 months (early scarring phase) post-treatment compared to control

Conclusions

These findings support the potential therapeutic value of autologous ADRC administration for reduction of HTS development following deep-partial cutaneous injury.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0704-1) contains supplementary material, which is available to authorized users.

Skin characteristics: normative data for elasticity, erythema, melanin, and thickness at 16 different anatomical locations

BACKGROUND

The clinical use of non-invasive instrumentation to evaluate skin characteristics for diagnostic purposes and to evaluate treatment outcomes has become more prevalent. The purpose of this study was to generate normative data for skin elasticity, erythema (vascularity), melanin (pigmentation), and thickness across a broad age range at a wide variety of anatomical locations using the Cutometer(®) (6 mm probe), Mexameter(®) , and high-frequency ultrasound in a healthy adult sample.

METHODS

We measured skin characteristics of 241 healthy participants who were stratified according to age and gender. Sixteen different anatomical locations were measured using the Cutometer(®) for maximum skin deformation, gross elasticity, and biological elasticity, the Mexameter(®) for erythema and melanin, and high-frequency ultrasound for skin thickness. Standardized measurement procedures were applied for all participants.

RESULTS

The means and standard deviations for each measured skin characteristic for females and males across five different age groups (20-29, 30-39, 40-49, 50-59, 60-69, and 70-85 years old) are presented. As previously described, there were variations in skin characteristics across age groups, anatomical locations, and between females and males highlighting the need to use site specific, age and gender matched data when comparing skin characteristics.

CONCLUSION

The reported data provides normative data stratified by anatomical location, age, and gender that can be used by clinicians and researchers to objectively determine whether patients' skin characteristics vary significantly from healthy subjects.