Isolation and Characterization of Stem Cells from the Anal Canal Transition Zone in Pigs.

BACKGROUND: Utilization of autologous stem cells has been proposed for the treatment of anal incontinence despite a lack of understanding of their mechanism of action and of the physiological healing process of anal sphincters after injury. AIMS: We aim to develop a technique allowing isolation and further study of local mesenchymal stem cells, directly from anal canal transition zone in pig. METHODS: Anal canal was resected "en bloc" from two young pigs and further microdissected. The anal canal transition zone was washed and digested with 0.1% type I collagenase for 45 min at 37 °C. The isolated cells were plated on dishes in mesenchymal stem cell medium and trypsinized when confluent. Cells were further used for flow cytometry analysis and differentiation assays. RESULTS: The anal canal transition zone localization was confirmed with H&E staining. Following culture, cells exhibited a typical "fibroblast-like" morphology typical of stem cells. Isolated cells were positive for CD90 and CD44 but negative for CD14, CD34, CD45, CD105, CD106, and SLA-DR. Following incubation with specific differentiation medium, isolated cells differentiated into adipocytes, osteoblasts, and chondrocytes, confirming in vitro multipotency. CONCLUSIONS: Herein, we report for the first time the presence of mesenchymal stem cells in the anal canal transition zone in pigs and the feasibility of their isolation. This preliminary study opens the path to the isolation of human anal canal transition zone mesenchymal stem cells that might be used to study sphincters healing and to treat anal incontinence.

Adipose-derived stem cell spheroids are superior to single-cell suspensions to improve fat autograft long-term survival.

Autologous fat transplantation is a widely used procedure for surgical reconstruction of tissues. The resorption rate of this transplantation remains high and unpredictable, reinforcing the need of adjuvant treatments that increase the long-term stability of grafts. Adipose-derived stem cells (ASC) introduced as single cells in fat has been shown clinically to reduce the resorption of fat grafts. On the other hand, the formulation of ASC into cell spheroids results in the enhancement of their regenerative potential. In this study, we developed a novel method to produce highly homogeneous ASC spheroids and characterized their features and efficacy on fat transplantation. Spheroids conserved ASC markers and multipotency. A regenerative gene expression profile was maintained, and genes linked to autophagy were upregulated whereas proliferation was decreased. Their secreted proteome was enriched in comparison with single-cell ASC suspension. Addition of spheroids to fat graft in an animal model of transplantation resulted in a better graft long-term stability when compared to single ASC suspension. In conclusion, we provide a novel method to manufacture homogenous ASC spheroids. These ASC spheroids are superior to ASC in single-cell suspension to improve the stability of fat transplants, reinforcing their potential in reconstructive surgery.

IL-25 participates in keratinocyte-driven dermal matrix turnover and is reduced in systemic sclerosis epidermis.

OBJECTIVES: Evidence shows that dysfunctional SSc keratinocytes contribute to fibrosis by altering dermal homeostasis. Whether IL-25, an IL-17 family member regulating many epidermal functions, takes part in skin fibrosis is unknown. Here we address the role of IL-25 in skin fibrosis. METHODS: The expression of IL-25 was evaluated by immunofluorescence and in situ hybridization in 10 SSc and seven healthy donor (HD) skin biopsies. Epidermal equivalents (EE) reconstituted by primary HD keratinocytes were used as a model to study transcriptomic changes induced by IL-25 in the epidermis. RNA expression profile in EEs was characterized by RNAseq. The conditioned medium (CM) from primary SSc and HD keratinocytes primed with IL-25 was used to stimulate fibroblasts. IL-6, IL-8, MMP-1, type-I collagen (Col-I), and fibronectin production by fibroblasts was assessed by ELISA. RESULTS: SSc epidermis expressed lower levels of IL-25 compared with HDs. In EEs, IL-25 regulated several molecular pathways related to wound healing and extracellular matrix remodelling. Compared with control CM, the CM from IL-25-primed keratinocytes enhanced the fibroblast production of MMP-1, IL-6 and IL-8, but not of Col-I nor fibronectin. However, IL-25 significantly reduced the production of Col-I when applied directly to fibroblasts. The activation of keratinocytes by IL-25 was receptor-dependent and evident after a very short incubation time (10 min), largely mediated by IL-1, suggesting enhanced and specific release of preformed mediators. CONCLUSIONS: These results show that IL-25 participates in skin homeostasis, and its decreased expression in SSc may contribute to skin fibrosis by favouring extracellular matrix deposition over degradation.

Quantitative magnetic resonance imaging: differentiating soft tissue implants and fillers used in cosmetic and reconstructive surgery.

OBJECTIVE: To evaluate the value of synthetic magnetic resonance imaging (MRI) and T2 mapping in distinguishing between different types of fillers in soft tissues. MATERIALS AND METHODS: Ex vivo fillers of buttock soft tissues (silicone, collagen, and different types of hyaluronic acid) were scanned using a synthetic MRI sequence at 1.5 and 3 T and an optimized T2 mapping sequence to measure the T2 relaxation times of the fillers ex vivo. Three patients addressed to assess complications with buttock fillers underwent MRI with the standard morphological sequences and an additional synthetic MRI sequence; T2 mapping was not performed for the patients. Two patients had silicone fillers, whereas the exact filler composition for the third patient was unknown. RESULTS: Measurements of T1 and T2 relaxation times of ex vivo fillers at 1.5 and 3 T using synthetic MRI showed that the silicone, collagen, and hyaluronic acid had distinct relaxation time characteristics. In vivo, the synthetic MRI correctly identified silicone in the two patients with known silicone fillers, showing low T1 and T2 values, whereas in the third patient with an unknown filler type, the synthetic MRI suggested a collagen filler, with intermediate relaxation time values. CONCLUSION: Quantitative sequences have the potential to differentiate between filler types in a noninvasive fashion.

[Training in reconstructive surgery in sub-Saharan Africa : the « 2nd Chance ¼ model]. / Formation en chirurgie réparatrice en Afrique subsaharienne : le modèle « 2nd Chance ¼.

Based in Geneva since 2010, 2nd Chance's mission is the development of reconstructive surgery care in resource-limited countries with a focus on sub-Saharan Africa, through teaching and advocacy activities. We develop the surgical management of patients on the one hand, providing training for African surgical teams. On the other hand, we support surgical procedures for patients, in the areas of reconstructive surgery, giant goiters, obstetric fistulas and anesthesia so that quality care is guaranteed for the long term. Despite the hurdles caused by the COVID crisis, training programs resumed at the end of 2020, with the implementation of the 2021-2025 strategy focusing on patient care and follow-up in the surgical setting through improved peri-operative safety and prevention of complications.

Basée à Genève depuis 2010, « 2nd Chance ¼ a pour mission le développement des soins en chirurgie réparatrice dans les pays à ressources limitées avec un focus sur l'Afrique subsaharienne, au moyen d'activités d'enseignement et de plaidoyer. Nous développons la prise en charge chirurgicale des patients tout en assurant la formation des équipes chirurgicales africaines dans les domaines de la chirurgie reconstructive, des goitres géants, des fistules obstétricales et de l'anesthésie afin que des soins de qualité soient garantis à long terme. Malgré les obstacles induits par la crise du Covid-19, les programmes de formation ont repris fin 2020, avec une stratégie 2021-2025 mettant l'accent sur les soins et le suivi du patient dans son contexte chirurgical.

The renin-angiotensin system in cutaneous hypertrophic scar and keloid formation.

Hypertrophic scar and keloid are two types of fibroproliferative conditions that result from excessive extracellular matrix production. The underlying pathological mechanism is not entirely clear. Activation of the renin-angiotensin system (RAS) is associated with fibrosis in various organs. RAS components including angiotensin II (Ang II), angiotensin AT1 and AT2 receptors, and angiotensin-converting enzyme (ACE) are expressed in the skin and act independently from the plasma RAS. AT1 receptors, which are usually the dominating receptor subtype, promote fibrosis and scar formation, while AT2 receptors inhibit the aforementioned AT1 receptor-coupled effects. Elevated angiotensin II (Ang II) levels acting on the AT1 receptor contribute to skin scar formation through increased expression of inflammatory factors such as interleukin-6 (IL-6), angiogenic factors such as vascular endothelial growth factor (VEGF) and fibrinogenic factors such as transforming growth factor-ß1 (TGF-ß1) and connective tissue growth factor (CTGF), while at the same time suppressing the anti-fibrotic tissue inhibitors of matrix metalloproteinase (TIMPs). First, small clinical trials have provided evidence that inhibition of the ACE/Ang II/ AT1 receptor axis may be effective in the treatment of hypertrophic scars/keloids. This review provides a detailed overview of the current literature on the RAS in skin, wound healing and scar formation and discusses the translational potential of targeting this hormonal system for treatment and prevention of hypertrophic scars and keloids.

Optimisation of phytochemical characteristics and antioxidative properties of Foeniculum vulgare Mill. seeds and Ocimum basilicum L. leaves superfine powders using new parting process.

INTRODUCTION: Fennel (Foeniculum vulgare Mill.) and basil (Ocimum basilicum L.) are two aromatic medicinal plants. Recently, a new parting process which is named CDS "Comminution and to control Diffraction Sieving" is taken into consideration and its positive effect on the extraction of bioactive compounds from the plants, without any solvent, is reported. OBJECTIVE: Study the effect of CDS on phytochemical properties of superfine powders of fennel seeds and basil leaves. METHODS: Fennel seeds and basil leaves superfine powders were fractionated as follows: 100-180 µm, 180-315 µm, 315-500 µm, > 500 µm and unsieved superfine powders. Extraction of polyphenols was carried out using hydromethanolic maceration. The essential oils were extracted by maceration with dichloromethane. The antioxidant activities were evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. Using liquid chromatography ultraviolet electrospray ionisation mass spectrometry (LC-UV-ESI-MS), concentrations of characterised phenolic compounds were measured. The essential oils compositions were characterised using gas chromatography mass spectrometry (GC-MS). RESULTS: In fennel seeds, the 100-180 µm fraction had maximum antioxidant activity and LC-UV-ESI-MS analyses proved that the best extraction of certain polyphenols was obtained in the 100-180 µm fraction. In basil leaves, the best antioxidant activity corresponded to the 315-500 µm fraction and LC-UV-ESI-MS analyses showed that the polyphenols were concentrated in the < 315 µm fractions. For both plants, GC-MS presented that the essential oils were concentrated in the 315-500 µm fraction. CONCLUSION: CDS as a new green parting process leads to improve the phytochemical properties of these two superfine plant powders in the specific granulometric classes.

[Keloid treatment†: Where do we stand†?] / Traitement des chéloïdes: où en sommes-nous?

Keloids are debilitating skin lesions that develop often as a result of minor skin lesions. Unlike hypertrophic scars, their main clinical feature is the tendency to extend beyond the initial limits of the wound. They can be responsible for pain and itching and may appear several months after the trauma. Their pathophysiology remains unknown but various mechanisms seem to be involved. Their management includes invasive and non-invasive approaches. At present, there is no satisfactory method or consensus on their management. Since the risk of recurrence after treatment is particularly high, a combination of different methods is proposed. In this article, we present the therapeutic strategy used in our institution concerning these problematic lesions.

Les chéloïdes sont des lésions cutanées débilitantes se développant suite à un traumatisme cutané souvent mineur. Contrairement aux cicatrices hypertrophiques, leur principale caractéristique clinique est la tendance à envahir la peau saine et à s'étendre au-delà des limites initiales de la plaie. Elles peuvent être responsables de douleurs et démangeaisons et apparaître plusieurs mois après le traumatisme. Leur physiopathologie reste inconnue mais divers mécanismes semblent impliqués. Leur prise en charge comprend des approches invasives et non invasives. A l'heure actuelle, il n'y a pas de méthode satisfaisante ni de réel consensus concernant leur traitement. Le risque de récidive étant particulièrement élevé, une combinaison de différentes méthodes est proposée. Dans cet article, nous présentons la stratégie utilisée dans notre établissement concernant ces lésions complexes.

Long-Segment Tracheal Reconstruction With Free Radial Forearm Flap Reinforced by Rib Cartilage.

Long-segment tracheal reconstruction remains a challenge. The ideal tracheal substitute should be an epithelialized tube to prevent stenosis and sufficiently rigid to maintain airflow patency. An autologous technique using a radial forearm free flap reinforced by rib cartilage has been recently described for tracheal reconstruction. We report here two cases of complex tracheal reconstruction with a modification of this technique, which consists of the creation of two independent skin paddles to allow the reconstruction of the trachea and a second adjacent defect (eg, cervical skin, esophagus). Airway patency was achieved with no stenosis, prolonged stenting, fistula, or necrosis after 26 and 44 months, respectively. We suggest that the satisfactory outcome obtained with this modified technique is a valuable option for tracheal and adjacent defect reconstruction without the need for a second flap.

Breast Reconstruction: A Century of Controversies and Progress.

Breast cancer treatment has dramatically changed over the past century. Since Halsted's first description of radical mastectomy in 1882, breast reconstruction has evolved slowly from being considered as a useless or even dangerous procedure by surgeons to the possibility nowadays of reconstructing almost any kind of defect. In this review on the development of breast reconstruction, we outline the historical milestone innovations that led to the current management of the mastectomy defect in an attempt to understand the economic, social and psychological factors, which contributed to slow down its acceptance for several decades.

Reactive Oxygen Species and NOX Enzymes Are Emerging as Key Players in Cutaneous Wound Repair.

Our understanding of the role of oxygen in cell physiology has evolved from its long-recognized importance as an essential factor in oxidative metabolism to its recognition as an important player in cell signaling. With regard to the latter, oxygen is needed for the generation of reactive oxygen species (ROS), which regulate a number of different cellular functions including differentiation, proliferation, apoptosis, migration, and contraction. Data specifically concerning the role of ROS-dependent signaling in cutaneous wound repair are very limited, especially regarding wound contraction. In this review we provide an overview of the current literature on the role of molecular and reactive oxygen in the physiology of wound repair as well as in the pathophysiology and therapy of chronic wounds, especially under ischemic and hyperglycemic conditions.

Factors Associated With Treatment Failure of Infected Pressure Sores.

OBJECTIVE: In this study, we assess interdisciplinary surgical and medical parameters associated to recurrences of infected pressure ulcers. BACKGROUND: There is a little in the published literature regarding factors associated with the outcome of treatment of infected pressure ulcers. METHODS: We undertook a single-center review of spinal injured adults hospitalized for an infected pressure ulcer or implant-free osteomyelitis and reviewed the literature on this topic from 1990-2015. RESULTS: We found 70 lesions in 31 patients (52 with osteomyelitis) who had a median follow-up of 2.7 years (range, 4 months to 19 years). The median duration of antibiotic therapy was 6 weeks, of which 1 week was parenteral. Clinical recurrence after treatment was noted in 44 infected ulcers (63%), after a median interval of 1 year. In 86% of these recurrences, cultures yielded a different organism than the preceding episode. By multivariate analyses, the following factors were not significantly related to recurrence: number of surgical interventions (hazard ratio 0.9, 95% confidence interval 0.5-1.5); osteomyelitis (hazard ratio 1.5; 0.7-3.1); immune suppression; prior sacral infections, and duration of total (or just parenteral) antibiotic sue. Patients with antibiotic treatment for <6 weeks had the same failure rate as those with as >12 weeks (χ test; P = 0.90). CONCLUSIONS: In patients with infected pressure ulcers, clinical recurrence occurs in almost two-thirds of lesions, but in only 14% with the same pathogen(s). The number of surgical debridements, flap use, or duration of antibiotic therapy was not associated with recurrence, suggesting recurrences are caused by reinfections caused by other extrahospital factors.

Hyperbaric oxygen therapy promotes wound repair in ischemic and hyperglycemic conditions, increasing tissue perfusion and collagen deposition.

The treatment of chronic wounds remains inconsistent and empirical. Hyperbaric oxygen therapy (HBOT) is a promising method to improve wound repair but there is still a lack of understanding of its mechanisms of action and its indications are not yet clearly defined. We studied the effects of HBOT in four different wound conditions by inflicting bilateral wounds on the dorsal aspect of the feet of nonischemic or ischemic limbs in normoglycemic or hyperglycemic rats. To create an ischemic condition, arterial resection was performed unilaterally. Forty-four animals received HBOT five times a week until complete wound closure. Wound repair was compared with 44 rats receiving standard dressing only. HBOT increased blood flow and accelerated wound closure in ischemic and hyperglycemic wounds, most significantly when the two conditions were combined. Wound contraction and reepithelialization were similarly stimulated by HBOT. The acceleration of wound contraction was not associated with increased myofibroblasts expression, nor fibroblast recruitment or higher cell count in the granulation tissue. Of note, we observed a significant increase in collagen deposition in early time points in ischemic wounds receiving HBOT. This data emphasizes that an early application of HBOT might be crucial to its efficacy. We concluded that wounds where ischemia and hyperglycemia are combined, as it is often the case in diabetic patients, have the best chance to benefit from HBOT.

Liver Trauma During Combined Liposuction and Abdominoplasty: A Rare but Potentially Lethal Complication.

Liposuction is a well-established procedure that is generally safe. However, rare complications can occur. The authors report on a 38-year-old woman who underwent combined abdominoplasty and liposuction at a private clinic. Four hours after the procedure, severe hypovolemic shock developed and required emergency transfer to a tertiary-care center. After primary fluid resuscitation, abdominal ultrasonography and computerized tomography revealed severe right-sided liver trauma, with active bleeding and free intra-abdominal fluid. Two attempts at right hepatic artery embolization failed to fully control the bleeding, and surgical hemostasis was required. After a 2-week hospitalization, the patient was discharged, and she returned to work 3 months later. Although it appears that this is the first reported case of liver trauma during liposuction, this potential complication should be kept in mind and identified early to permit efficient and effective management.

Long-term follow-up of cadaveric breast augmentation: what can we learn?

Breast augmentation with cadaveric fat graft has long been available to patients in Eastern European countries, primarily in the Soviet Union and Eastern Germany. Most such procedures were performed from the 1970s to the 1990s. Although only a few case reports have been published, all of which involved complications that appeared several years after the procedure, it appears that, surprisingly, this nonvascularized and incompatible immunologic tissue is relatively well tolerated. We present the case of a 45-year-old Russian woman who underwent breast explantation, due to breast hardness and pain, 15 years after breast augmentation with cadaveric fat grafting. Through genetic studies, we confirmed that the host and the graft were HLA incompatible. Moreover, results of analyses excluded the possibility of an acute or chronic immunologic rejection by the host. We suppose that the early complications that often occur in such cases might result from a nonspecific, inflammatory reaction induced by acute tissue ischemia and necrosis, and the late local complications that occur years later may relate more to chronic inflammation, due to nonvascularized tissue, than to immunologic rejection. Therefore, we propose that different mechanisms may explain how this allogenic fat tissue could have been tolerated by the patient's immune system. We particularly underline the immunomodulatory effect of mesenchymal stem cells, which are abundant in adipose tissues. This characteristic of fat tissue should be investigated further to assess its potential in treating autoimmune diseases or reducing the likelihood of allograft rejections.

Nipple-areola complex prosthesis as a new arsenal for breast reconstruction.

Nipple and areola complex (NAC) recreating is primordial to achieve a complete breast reconstruction. Some patients would not benefit or choose to undergo surgical or tattoo NAC reconstruction. Recently, innovative NAC silicone prostheses have been developed that are applied over the skin and come in various shapes, sizes, and colors to match different NAC tones and sizes. Our prospective study aims to evaluate for the first time, to our knowledge, the safety of these prostheses and patients' and surgeons' satisfaction using a 30-day survey. Twenty patients using these NAC prostheses after unilateral breast reconstruction postmastectomy with NAC excision were included. All patients except one (95%) were satisfied/very satisfied with the aspect and symmetry of NAC prostheses compared with native contralateral NAC. All patients were more/much more satisfied with their body image and self-esteem using the NAC prostheses. Except for 2 (90%), no participant presented any skin reaction, infection, or erosion. Most patients (68.75%) used the prosthesis every day, and others-occasionally. All participants stated they would recommend these prostheses to other women as a temporary or definitive solution. With these promising results demonstrating a high safety and satisfaction rate, we are confident that this simple, safe, noninvasive, and cost-effective device should be proposed to all patients to improve the management of breast reconstruction and offer body integrity to patients. Health insurance should consider reimbursement for these prostheses in patients after mastectomy or with NAC deformation after trauma, surgery, or congenital.

The Impact of the COVID-19 Pandemic on Reconstructive Surgery and Training Programs in Sub-Saharan Africa: A Cross-Sectional Survey.

Background: In Sub-Saharan Africa, which already faces challenges due to a lack of surgeons and facilities, the COVID-19 pandemic could significantly disrupt surgical activities and training programs. "2nd Chance", a non-governmental organization providing training program to enhance local reconstructive surgery capacity in this region since 2015, could play a crucial role in addressing these issues. We aimed to investigate the impact of the COVID-19 on the activity of sub-Saharan African reconstructive surgeons collaborating with "2nd Chance" organization and evaluate its effect on the organization's training programs. Methods: In the course of 2022, an online cross-sectional survey was conducted among reconstructive surgeons working in sub-Saharan African countries and collaborating with "2nd Chance". The survey consisted of 57 questions covering demographics, impacts of COVID-19 on personal life, clinical and training activities. Results: Of 469 surgeons eligible for the study, 240 were included and 51 responded. The impact of COVID-19 was felt personally in terms of health and stress. Clinical activities were severely affected, with some reporting higher mortality due to surgical cancellations and delays. Regarding training, there was a shift from practical to theoretical learning, though overall impact was moderate. One-third of participants were able to attend "2nd Chance" workshops. Among the 17 planned workshops, 9 were successfully conducted, and 4 of them exclusively featured African trainers. Conclusion: The COVID-19 pandemic had substantial consequences on reconstructive surgery in sub-Saharan Africa, impacting more clinical practices than training programs. Collaboration between African and European trainers proved essential during the pandemic. In future pandemics, South-South collaborations should be prioritized.

NADPH oxidase 4 is dispensable for skin myofibroblast differentiation and wound healing.

Differentiation of fibroblasts to myofibroblasts is governed by the transforming growth factor beta (TGF-ß) through a mechanism involving redox signaling and generation of reactive oxygen species (ROS). Myofibroblasts synthesize proteins of the extracellular matrix (ECM) and display a contractile phenotype. Myofibroblasts are predominant contributors of wound healing and several pathological states, including fibrotic diseases and cancer. Inhibition of the ROS-generating enzyme NADPH oxidase 4 (NOX4) has been proposed to mitigate fibroblast to myofibroblast differentiation and to offer a therapeutic option for the treatment of fibrotic diseases. In this study, we addressed the role of NOX4 in physiological wound healing and in TGF-ß-induced myofibroblast differentiation. We explored the phenotypic changes induced by TGF-ß in primary skin fibroblasts isolated from Nox4-deficient mice by immunofluorescence, Western blotting and RNA sequencing. Mice deficient for Cyba, the gene coding for p22phox, a key subunit of NOX4 were used for confirmatory experiments as well as human primary skin fibroblasts. In vivo, the wound healing was similar in wild-type and Nox4-deficient mice. In vitro, despite a strong upregulation following TGF-ß treatment, Nox4 did not influence skin myofibroblast differentiation although a putative NOX4 inhibitor GKT137831 and a flavoprotein inhibitor diphenylene iodonium mitigated this mechanism. Transcriptomic analysis revealed upregulation of the mitochondrial protein Ucp2 and the stress-response protein Hddc3 in Nox4-deficient fibroblasts, which had however no impact on fibroblast bioenergetics. Altogether, we provide extensive evidence that NOX4 is dispensable for wound healing and skin fibroblast to myofibroblast differentiation, and suggest that another H2O2-generating flavoprotein drives this mechanism.

Adipose-Derived Stromal Cells within a Gelatin Matrix Acquire Enhanced Regenerative and Angiogenic Properties: A Pre-Clinical Study for Application to Chronic Wounds.

This study evaluates the influence of a gelatin sponge on adipose-derived stromal cells (ASC). Transcriptomic data revealed that, compared to ASC in a monolayer, a cross-linked porcine gelatin sponge strongly influences the transcriptome of ASC. Wound healing genes were massively regulated, notably with the inflammatory and angiogenic factors. Proteomics on conditioned media showed that gelatin also acted as a concentrator and reservoir of the regenerative ASC secretome. This secretome promoted fibroblast survival and epithelialization, and significantly increased the migration and tubular assembly of endothelial cells within fibronectin. ASC in gelatin on a chick chorioallantoic membrane were more connected to vessels than an empty sponge, confirming an increased angiogenesis in vivo. No tumor formation was observed in immunodeficient nude mice to which an ASC gelatin sponge was transplanted subcutaneously. Finally, ASC in a gelatin sponge prepared from outbred rats accelerated closure and re-vascularization of ischemic wounds in the footpads of rats. In conclusion, we provide here preclinical evidence that a cross-linked porcine gelatin sponge is an optimal carrier to concentrate and increase the regenerative activity of ASC, notably angiogenic. This formulation of ASC represents an optimal, convenient and clinically compliant option for the delivery of ASC on ischemic wounds.

Epigenetic remodeling of downstream enhancer regions is linked to selective expression of the IL1F10 gene in differentiated human keratinocytes.

Interleukin (IL)-38, encoded by the IL1F10 gene, is a member of the IL-1 family of cytokines. IL-38 is constitutively expressed in epithelia in healthy humans, and in particular in epidermal keratinocytes in the skin. IL-38 expression is closely correlated with keratinocyte differentiation. The aim of this study was to further characterize the regulation of IL1F10 expression and the mechanisms involved in its selective induction in differentiated human keratinocytes. We observed coordinated expression of two IL1F10 transcripts, transcribed from two different promoters, upon differentiation of primary human keratinocytes. Using ENCODE datasets and ChIP-qPCR on ex vivo isolated normal human epidermis, we identified regulatory regions located downstream of the IL1F10 gene, which displayed features of differentiated keratinocyte-specific enhancers. Expression of the IL1F10 gene was linked to changes in the epigenetic landscape at these downstream enhancer regions in human epidermis. Overexpression of the transcription factors KLF4 and TAp63ß in an immortalized normal human keratinocyte (iNHK) cell line promoted the expression of mRNA encoding the differentiation markers keratin 10 and involucrin, and of IL1F10. ChIP-qPCR experiments indicated that KLF4 and TAp63ß overexpression also modified the chromatin state of the proximal downstream enhancer region, suggesting a role for KLF4 and TAp63ß in directly or indirectly regulating IL1F10 transcription. In conclusion, expression of the IL1F10 gene in differentiated keratinocytes in normal human epidermis involves coordinated transcription from two promoters and is linked to epigenetic remodeling of enhancer regions located downstream of the gene.