Clinical, biophysical, immunohistochemical, and in vivo reflectance confocal microscopy evaluation of the response of subjects with sensitive skin to home-use fractional non-ablative photothermolysis device.

BACKGROUND: Fractional photothermolysis using professional devices is a well-accepted and a widely used technique for skin rejuvenation. Recently, the technology has also been implemented in devices for home-use. Yet, a subpopulation of consumers exists that reacts excessively to this stimulation and reports "sensitive skin" (SS). OBJECTIVE: The goal of this study was to evaluate the response of subjects with SS and NSS to fractional non-ablative photothermolysis to provide additional insights in the pathophysiology of SS. METHODS: Subjects with SS and non-sensitive skin (NSS), selected using a proprietary questionnaire were stimulated by applying a home-use fractional non-ablative photothermolysis device. Self-reported perceptions and objective effects were evaluated after 0.5, 8, 24, and 72 hours by clinical, biophysical and immunohistochemical assessment, and in vivo reflectance confocal microscopy (RCM). RESULTS: Significantly fewer mast cells were found in SS compared to NSS subjects, 0.5 and 72 hours after stimulus based on tryptase staining, and SS subjects report discomfort more frequently. Immunohistochemical biomarkers revealed new insights in the effects of fractional non-ablative photothermolysis, which were supported by RCM: peri- and interlesional epidermal proliferation, and changes in keratinocyte differentiation. CONCLUSION: Previously, we have already reported that SS could be elicited by mechanical and chemical stimuli. Thus, mild yet excessive self-reported perceptions described here supports the hypothesis about existence of generalized skin sensitivity. Furthermore, it supports a view point suggesting involvement of TRPV1 receptors in this phenomenon. While histological evaluation, in line with our previous results points to the role of mast cells in SS, overall, however, fractional non-ablative photothermolysis causes only mild damage, nearly equal in SS and NSS and could be used as an in vivo model for skin regeneration without manipulating the skin barrier. Lasers Surg. Med. 48:474-482, 2016. © 2016 Wiley Periodicals, Inc.

Heat shocks enhance procollagen type I and III expression in fibroblasts in ex vivo human skin.

BACKGROUND: The well-known characteristics of aging skin are the development of fine lines and wrinkles, but changes in skin tone, skin texture, thickness and moisture content are also aspects of aging. Rejuvenation of the skin aims at reversing the signs of aging and can be established in the epidermis as well as in the dermis. Aged dermis, in fact, has a degenerated collagen matrix. To regenerate this matrix, fibroblasts need to be stimulated into synthesizing new collagen. AIMS: In this study, the effects of heat shocks of different temperatures on human dermal fibroblasts in ex vivo skin on the expression of procollagen 1, procollagen 3, heat shock protein (hsp)27, hsp47, and hsp70 are investigated. MATERIALS AND METHODS: The heat shocks were applied on ex vivo skin samples by immersing the samples in heated phosphate-buffered saline of 45 °C or 60 °C. Metabolic activity was measured and at similar time points propidium-iodide-calceine staining was performed to establish cell viability. Quantitative polymerase chain reaction (qPCR) was performed after the heat shock to determine gene expression levels relative to the reference temperature. Furthermore, PicroSirius Red and hematoxylin stainings were performed to visualize the collagen network and the cells. RESULTS: The skin samples were shown to be viable and metabolically active. Histology indicated that the heat shocks did not influence the structure of the collagen network or cell appearance. qPCR results showed that in contrast to the 45 °C heat shock the 60 °C heat shock resulted in significant upregulations of procollagen type I and III, hsp70 and hsp47. CONCLUSION: A 60 °C, heat shock stimulates the human dermal fibroblasts in ex vivo skin to upregulate their procollagen type I and type III expression.

Pulsed heat shocks enhance procollagen type I and procollagen type III expression in human dermal fibroblasts.

BACKGROUND: The formation of wrinkles is associated with degeneration of the collagen matrix. For regeneration of the matrix, fibroblasts need to be stimulated in producing new collagen. AIMS: In this study, the effect of short-pulsed heat shocks on gene expression of procollagen type I, procollagen type III, heat shock protein (hsp)27, hsp47 and hsp70 and on the expression of remodeling markers, procollagen type I carboxy-terminal peptide (P1P) and carboxy-terminal telopeptide of type I (ICTP), of human dermal fibroblasts in vitro, is investigated. MATERIALS AND METHODS: Temperatures of 45 degrees C and 60 degrees C were used for the heat shocks. The proliferation rates, viability and metabolic activity were measured directly after the pulsed heat shocks and quantitative PCR was performed at five different time points after the heat shocks. Enzyme Immuno Assays were performed to determine the concentrations of P1P and ICTP. RESULTS: A decreased proliferation rate of the 60 degrees C heat shocked cells was shown, whereas the viability and metabolic activity did not differ. Furthermore, gene expressions were upregulated in both 45 degrees C and 60 degrees C heat-shocked cells. However, remodeling marker analyses showed a larger amount of collagen produced by 60 degrees C heat-shocked cells. CONCLUSION: It can be concluded that these findings, together with upregulation in gene expression, show that it is possible to stimulate the cells to produce more collagen with short-pulsed heat shocks.

Mechanical properties and failure of Streptococcus mutans biofilms, studied using a microindentation device.

Knowledge of mechanical properties and failure mechanisms of biofilms is needed to determine how biofilms react on mechanical stress. Methods currently available cannot be used to determine mechanical properties of biofilms on a small scale with high accuracy. A novel microindentation apparatus in combination with a confocal microscope was used to determine the viscoelastic properties of Streptococcus mutans biofilms. The apparatus comprises a small glass indenter and a highly sensitive force transducer. It was shown that the present biofilm, grown under still conditions, behaves as a viscoelastic solid with a storage modulus of 1-8 kPa and a loss modulus of 5-10 kPa at a strain of 10%. Biofilm failure was investigated visually through a confocal microscope by dragging the indenter through the biofilm. It was shown that the tensile strength of the biofilm is predominantly determined by the tensile strength of the extracellular polysaccharide matrix. The combination of microindentation and confocal microscopy is a promising technique to determine and characterize the mechanical properties of soft materials in various fields of microbiology.

The effectiveness of massage treatment on cellulite as monitored by ultrasound imaging.

BACKGROUND/AIMS: The visual appearance of cellulite or the'orange peel'look of skin is a common cosmetic problem for many women. Cellulite, or more correctly lipodystrophy, is a modification of the adipose tissue, whereby the fat lobules are swollen as the result of a disturbed blood and lymph micro-circulation and fibrosclerose of connective tissue. In the wealthy diversity of products against cellulite, objective methods to measure their efficacy are of growing importance. The purpose of this study is to establish the effectiveness of a skin massage treatment by quantifying the changes in the skin via ultrasound imaging, during and following treatment. METHODS: Using 20 MHz C-mode ultrasound scanning, a three-dimensional subsurface is constructed that represents the dermis-hypodermis tissue interface. In normal cellulite-free skin, this interface is smooth. In the case of cellulite, however, the dermis-hypodermis junction appears as an irregular surface. Qualitatively, the effect of cellulite treatment is inferred from changes in the shape of this junction. In order to quantify the effect, we chose to monitor the junction area. For the treatments, we used a specially designed handheld electro-mechanical massage device that was moved along the thigh. Treatments were conducted for 3 months, three times a week, during 15 min on each upper leg of 20 healthy female volunteers with moderate symptoms of cellulite (Curri's classification 1-2). Ultrasound measurements were performed monthly, and continued for 2 months after the treatments were stopped. RESULTS: The results, on average, indicate a significant smoothening of the dermis-hypodermis surface (relative surface area reduction 34+3%, 50±3% and 56±2% after 1, 2 and 3 months of treatment, respectively). The smoothening can be described by a mono-exponential function with a time constant of 1.1 month. After the treatments were discontinued, the relative surface area gradually increased (with a time constant of 2.6 month), which indicates that the effect of massage is not permanent. CONCLUSION: Treatment of cellulite by means of an electro-mechanical skin fold massage apparatus significantly smoothens the structure of the dermis-hypodermis interface. Three-dimensional ultrasound imaging of the dermis-hypodermis junction could serve as an objective method to monitor the effectiveness of cellulite treatment.

Diffraction and scattering at antiglare structures for display devices.

Antiglare layers for display devices feature a rough surface structure that scatters the incident light and thereby reduces the specular reflectivity of the screen. The same structure will, however, also diffuse part of the light from the phosphor layer, resulting in a degradation of image quality. The microstructure, light-scattering properties, and effects on image contrast and resolution of some relevant antiglare structures are examined. A model based on scalar diffraction theory that relates the various optical properties to the surface microstructure is presented.

Excited states and primary photochemical reactions in the photosynthetic bacterium Heliobacterium chlorum.

The charge separation and excited states of antenna bacteriochlorophyll in membrane fragments of the recently discovered photosynthetic bacterium Heliobacterium chlorum were studied by absorbance-difference spectroscopy. Formation of singlet excited states of bacteriochlorophyll g with a lifetime of 200 ps or less was observed as the disappearance of the ground state absorption bands. From the absorbance-difference spectra, it was concluded that the primary photochemical reaction consists of the transfer of an electron from the primary donor P-798 to a possibly bacteriochlorophyll c-like pigment absorbing at 670 nm. Electron transfer to the secondary acceptor occurred with a time constant of about 500 ps. The midpoint potential of this acceptor (between -450 and -560 mV) and the absence of significant absorbance changes in the near-infrared upon its reduction suggest that this acceptor is an iron-sulfur center. It is concluded that the primary photochemistry of H. chlorum is similar to that of green sulfur bacteria.