Tailoring the growth and proliferation of human dermal fibroblasts by DNA-based polymer films for skin regeneration.

The use of DNA as a functional biomaterial for therapeutic, diagnostic, and drug delivery applications has been prominent in recent years, but its use as a scaffold for tissue regeneration is still limited. This study aimed to evaluate the biocompatibility and interaction of DNA-based polymeric films (DNA-PFs) with primary human fibroblasts (PHF) for regenerative medicine and wound healing purposes. The morphological characterization of the films was performed by scanning electron microscopy, SEM-energy-dispersive X-ray spectroscopy, and atomic force microscopy analysis. Cell viability, cell cycle kinetics, oxidative stress, and migration studies were carried out at 48 and 72 hr of incubation and compared to control cells. Cell adhesion was impaired in the first 24 hr, DNA-PFs with higher concentrations of DNA (1.0 and 2.0 g/L) this effect was not seen in DNA-PFs (0.5 g/L), explained by the difference in topography and roughness of DNA-PFs, but it was overcome after 48 hr of incubation. PHF seeded on DNA films showed higher proliferation and migration rates than the control after 48 hr of incubation, with the maintenance of cell morphology and lower cytotoxicity and oxidative stress during the evaluation time. Therefore, these results indicate that DNA-PFs are highly biocompatible and provide a suitable microenvironment for dermal fibroblasts to maintain their activity, helping build new and more complex biomaterials suitable for future tissue repair applications.

Radiofrequency therapy in esthetic dermatology: A review of clinical evidences.

BACKGROUND: Chronological skin aging causes the modification of genetic material through enzymes and proteins changes. The process reduces cellular proliferation, along with loss of tissue elasticity, reduced ability to regulate aqueous exchanges, and inefficient tissue replication. Appearance is negatively affected by cumulative changes in coloration, texture, and elasticity over time. The increase in the population's average life expectancy boosts the search for cosmetic therapies that can delay aging, mostly for the noninvasive modalities. Among the various options, radiofrequency therapy is a technique that can help reduce the effects of skin aging. AIM: Therefore, this study aims to review clinical evidence provided by scientific literature on the benefits of using radiofrequency therapy in reducing skin aging effects. METHODS: A review of the literature concerning skin aging, characteristics of radiofrequency therapy, and radiofrequency therapy in the treatment of skin laxity and mechanism of action was conducted using PubMed. RESULTS: The included studies have suggested that the mechanism of radiofrequency action is heating the dermis while preserving the epidermis. This heating causes immediate collagen denaturation, which is followed by the formation of new collagen, naturally providing skin tightening and greater elasticity. CONCLUSION: Even when used as single therapeutic modality, radiofrequency seems to meet the expectations in reducing the effects of skin aging.

Skin thickness as a potential marker of gestational age at birth despite different fetal growth profiles: A feasibility study.

BACKGROUND: New methodologies to estimate gestational age (GA) at birth are demanded to face the limited access to obstetric ultrasonography and imprecision of postnatal scores. The study analyzed the correlation between neonatal skin thickness and pregnancy duration. Secondarily, it investigated the influence of fetal growth profiles on tissue layer dimensions. METHODS AND FINDINGS: In a feasibility study, 222 infants selected at a term-to-preterm ratio of 1:1 were assessed. Reliable information on GA was based on the early ultrasonography-based reference. The thicknesses of the epidermal and dermal skin layers were examined using high-frequency ultrasonography. We scanned the skin over the forearm and foot plantar surface of the newborns. A multivariate regression model was adjusted to determine the correlation of GA with skin layer dimensions. The best model to correlate skin thickness with GA was fitted using the epidermal layer on the forearm site, adjusted to cofactors, as follows: Gestational age (weeks) = -28.0 + 12.8 Ln (Thickness) - 4.4 Incubator staying; R2 = 0.604 (P<0.001). In this model, the constant value for the standard of fetal growth was statistically null. The dermal layer thickness on the forearm and plantar surfaces had a negative moderate linear correlation with GA (R = -0.370, P<0.001 and R = -0.421, P<0.001, respectively). The univariate statistical analyses revealed the influence of underweight and overweight profiles on neonatal skin thickness at birth. Of the 222 infants, 53 (23.9%) had inappropriate fetal growths expected for their GA. Epidermal thickness was not fetal growth standard dependent as follows: 172.2 (19.8) µm for adequate for GA, 171.4 (20.6) µm for SGA, and 177.7 (15.2) µm for LGA (P = 0.525, mean [SD] on the forearm). CONCLUSIONS: The analysis highlights a new opportunity to relate GA at birth to neonatal skin layer thickness. As this parameter was not influenced by the standard of fetal growth, skin maturity can contribute to clinical applications.

Skin gland concentrations adapted to different evolutionary pressures in the head and posterior regions of the caecilian Siphonops annulatus.

Amphibian skin is rich in mucous glands and poison glands, secreting substances important for gas exchange and playing a fundamental role in chemical defense against predators and microorganisms. In the caecilian Siphonops annulatus (Mikan, 1920) we observed a concentration of enlarged mucous glands in the head region. In the posterior region of the body a similar concentration is made up of enlarged poison glands. These accumulations of glands structurally resemble the macroglands previously reported in anurans and salamanders. The skin glands in these regions are each surrounded by collagen walls forming a honeycomb-like structure. The collagen network in the head region firmly attaches to tiny pits in the bones of the skull. The two extremities of the body produce different secretions, containing exclusive molecules. Considering the fossorial lifestyle of caecilians, it seems evident that the secretions of the head and caudal region serve different functions. The anterior macrogland of mucous glands, rich in mucous/lipid secretion, in conjunction with the funnel-shaped head, may act to lubricate the body and penetrate the soil, thus facilitating locomotion underground. The blunt posterior end bearing an internalized macrogland of poison glands in the dermis may act in chemical defense and/or by blocking invasion of tunnels.

Sustituto dérmico: Experiencia en el postgrado de cirugía plástica reconstructiva del Instituto Autónomo Hospital Universitario de los Ándes / Dermal substitute: Postgraduate experience in reconstructive plastic surgery at the Instituto Autonomo Hospital Universitario de los Andes

La piel tiene una función primordial en el control de la integridad del medio interno. En consecuencia, su pérdida en proporciones importantes como aquellas que ocurren en las perdidas traumáticas, cirugías reconstructivas, cirugías oncológicas y grandes quemados, es factor predisponente a complicaciones. En las últimas décadas se han desarrollado diversos métodos que permiten remplazar los principales componentes de la piel. Es así como el tejido dérmico ha sido homologado mediante sustitutos a base de biopolímeros de origen animal. Los equivalentes dérmicos le confieren resistencia mecánica a los injertos y gradualmente facilitan su colonización y reemplazo por fibroblastos y células endoteliales del paciente. La matriz dérmica es un biomaterial que ha sido utilizado por la cirugía plástica, con el propósito de reconstruir en superficie o volumen un tejido que ha sido afectado y que presenta alteraciones en su morfología. Se presenta una revisión y análisis de un ensayo clínico multicéntrico de los pacientes donde se efectuaron 336 biopsias en serie de 131 pacientes participantes, en un lapso de 7 días a 2 años post-aplicación del producto. Se obtiene como resultado que la matriz de regeneración dérmica fue bien tolerada, no hubo notificaciones de respuestas inmunológicas o histológicas con importancia clínica a la implantación del producto. En las evaluaciones clínicas no hubo notificaciones de rechazo a la matriz. Además se recopilaron datos sobre la colonización o infección de las heridas. Las consecuencias de una infección en los lugares tratados con la matriz incluyen pérdida parcial o total de absorción del producto(AU)

The skin has a major role in controlling the integrity of the internal environment. Consequently, their loss in major proportions as those occurring in traumatic losses, reconstructive surgery, cancer surgery and severe burns, is a predisposing factor for complications. In the last decades various methods have been developed that allow replacing the main components in the skin. Thus the dermal tissue has been approved by biopolymers based substitutes animal. Dermal equivalents confer mechanical strength to the grafts and gradually facilitate colonization and replacement by fibroblasts and endothelial cells of the patient. Dermal matrix is a biomaterial that has been used for plastic surgery, for the purpose of reconstructing or surface tissue that volume has been affected and having alterations in morphology. A review and analysis of a multicenter clinical trial of 336 patients where biopsies were performed in series of 131 patients participating in a span of 7 days to 2 years post- spraying. As result the dermal regeneration matrix was well tolerated, no notifications immune responses or clinically significant histological to implantation of the device. In no clinical assessments of rejection notices to the matrix. Also collected data on the colonization or infection of wounds. The consequences of infection sites treated with the matrix include partial or total loss of absorption(AU)

Hyaluronan in the epidermal and the dermal extracellular matrix: its role in cutaneous hydric balance and integrity of anuran integument.

New researches have revealed that hyaluronan (HA) is not a passive molecule. HA has being pointed out to participate in many processes, such as cell interactions, proliferating and migrating cell events and function as hydrate agent. The present study was undertaken to localize HA in Bufo ictericus integument providing a better understating for the role of cutaneous HA. Paraffinized sections were stained with haematoxylin-eosin and with 1% Alcian blue 8GX at pH 1.0 and 2.5. Alcianophilic reaction was visualized in both spongious dermis and Eberth-Katschenko layer. The mucus cells of mucus glands were also stained with AB methods. Besides these histological techniques, the localization of HA was performed using the FITC-labeled HA probe labeled with fluorescein isothiocyanate. In the extracellular matrix of spongious dermis, the reaction for HA was evident, being less intense in hypodermis and in pericellular keratinocyte matrix of the cornified tubercles regions. Thus, since HA was localized in the pericellular epidermal matrix and in the spongious dermis of anuran integument, it plays an important role in hydric balance, and is essential for integument integrity and functionality.

Histology of the sternal and suprapubic skin areas in lion tamarins (Leontopithecus sp. Callitrichidae-primates).

Though knowledge regarding the biology and morphology of lion tamarins is scarce in the literature, it is very important for their conservation. This paper focuses on the anatomical and histological aspects of the glands involved in the scent-marking behavior of lion tamarins. It examines the histological aspects of sternal and suprapubic skin sections of specimens that were preserved in formaldehyde and were the property of the Rio de Janeiro Primatology Center Museum. Eighteen specimens from three lion tamarin (Leontopithecus sp.) species (L. rosalia, L. chrysomelas, and L. chrysopygus) were analyzed. Both sexes were represented, and macroscopic hypertrophy was quantified by direct observation of the tegument on the sternal area and classified as discrete, moderate, or accentuated for each specimen. The skin of both sexes had a high degree of histological resemblance to that of other primates, including humans. The epidermis presented stratified squamous keratinous epithelia, with a few cellular layers and dermis with cutaneous appendages (i.e., hair follicles and both sebaceous and sweat glands). The dermal papillae were short, and the sebaceous and apocrine sweat glands resembled those of humans. These glands were present in the dermis of the analyzed skin fragments of both sternal and suprapubic regions in great numbers. Furthermore, we were able to establish a relationship between the macroscopic appearance of the sternal tegument and the degree of microscopic gland hyperplasia.