Acute effect of solar-simulated radiation on epidermal thickness assessed by confocal laser scanning microscopy in vivo

Acute effects of local cold therapy in superficial burns on pain, in vivo microcirculation, edema formation and histomorphology

BACKGROUND

Local cold therapy for burns is generally recommended to relief pain and limit tissue damage, however, there is limited data of its physiological benefit. This study aimed to evaluate pathophysiological effects of cold therapy in superficial burn on microcirculation, edema formation, and histomorphology.

METHODS

In 12 volunteers (8f, 4m; aged 30.4±14.1 years) circumscribed superficial burn was induced on both hand back and either left untreated as control (control-group) or treated by local-cold-application (cold-treatment-group). Prior to burn (t0), immediately (t1), 15 min (t2), and 30 min (t3) following cold therapy, following parameter was evaluated using intravital-microscopy; epidermal-thickness (ET), granular-cell-size (GCS), individual-blood-cell-flow (IBCF), and functional-capillary-density (FCD).

RESULTS

Both ET and GCS increased significantly more in control-group and slightly in cold-treatment-group in t1, while turns to insignificant t2 onwards. IBCF and FCD raised up in control-group compared to dramatically decrease in cold-treatment-group in t1. In t2 both parameter remains in control-group and increased in cold-treatment-group. Comparison of both groups for IBCF and FCD indicates significant difference in t1 and t2, however, insignificant in t0 and t3.

CONCLUSIONS

Microcirculation, edema formation, and histomorphology of superficial burn has been significantly influenced through immediate cold therapy, however, this alterations are transient and turns to ineffective after 30 min.

Protective effects of green tea extracts on photoaging and photommunosuppression

OBJECTIVES

This study aimed to investigate whether the sunscreen-containing 2-5% green tea extracts (GTEs) protect ultraviolet irradiation (UVR)-induced photoaging and photoimmunosuppression.

MATERIALS AND METHODS

Twenty volunteers were exposed to repetitive solar-simulated UVR (ssUVR) on the upper back at a dosage of 1.5 minimal erythema doses (MED) per day for four consecutive days. Thirty minutes before each UVR and 6, 24, and 48 h after the last UV exposure, the products containing vehicle, and 2-5% GTEs were applied onto five sites on the dorsal skin, respectively. The skin biopsies were obtained 72 h after the last UVR. The thickness of the stratum corneum and epidermis was measured under the microscope and the expression of cytokeratins (CK)-5/6, CK16, metalloproteinases (MMP)-2, MMP-9, and the CD1a(+) Langerhans cells (LCs) were determined using immunohistochemistry.

RESULTS

Our results showed that UVR substantially induced cutaneous erythema, thickening of the epidermis, overexpression of CK5/6, CK16, MMP-2, MMP-9, and depletion of CD1a(+) LCs. The sunscreens containing different concentrations of GTEs conferred significant protection against the photoaging and photoimmunology-related biological events. Interestingly, the protective effects were not parallel to the concentrations of GTEs, with 2% and 3% GTEs showing the most efficacious photoprotection.

CONCLUSIONS

GTEs-containing sunscreens have potential photoprotective effects on UVR-induced photoaging and photoimmunosuppression.

Assessment of microcirculatory influence on cellular morphology in human burn wound healing using reflectance-mode-confocal microscopy

Previous studies have assessed the effects of changes in microcirculation on wound healing; however, the influence of microcirculation on tissue histomorphology remains widely unknown. Reflectance-mode-confocal microscopy (RMCM) enables in vivo tissue observation on a cellular level. We present RMCM data evaluating the local microcirculation and assess the influence on histomorphology during burn healing. RMCM was performed in 12 patients (aged; 36.2+/-14.2 years, maximum-burn-extent: 4% total body surface area) at times 12, 36, and 72 hours after a superficial burn. The following parameters were assessed: quantitative blood-cell-flow (cbf), epidermal thickness (Emin), basal-layer thickness (tbl), and granular cell-size (Agran). Cbf was found to be 54+/-3.6 cells/minutes (control), increased to 91+/-3.6 cells/minutes (p<0.05) 12 hours postburn; decreased to 71+/-6.1 cells/minutes (p<0.05) (36 hours), and to 63+/-2.3 cells/minutes (p>0.05) 72 hours postburn. Emin was 43.74+/-3.87 mum (control), increased to 51.67+/-4.04 mum (p<0.05) 12 hours, decreased to 48.67+/-3.51 mum (p<0.05) 36 hours, and to 45.33+/-3.21 mum (p>0.05) at 72 hours postburn. Tbl was 14.17+/-0.6 mum (control), increased to 16.93+/-1.15 mum (p<0.05) 12 hours, decreased to 15.93+/-1.20 mum (p<0.05) 32 hours, and to 15.00+/-0.85 mum (p>0.05) 72 hours postburn. Agran was 718+/-56.20 mum(2) (control), increased to 901+/-66.02 mum(2) (p<0.05) 12 hours, decreased to 826+/-56.86 mum(2) 36 hours, and 766+/-65.06 mum(2) at 72 hours postburn. RMCM enables in vivo observation of wound microcirculation and allows direct assessment of vascular effects on cutaneous histomorphology during the healing course of superficial burns.

Histometric and histomorphologic comparison of combustion and ambustion using in vivo reflectance-confocal microscopy

BACKGROUND

When combustion and ambustion induce a superficial injury, they are summarized as superficial burns, regardless of the underlying cause. Reflectance-confocal microscopy (RCM) allows noninvasive imaging of the human skin on morphological features. We hypothesized that combustion and ambustion have different histomorphological effects on the human skin.

METHODS

Superficial burns caused by combustion (CO-group, five females, three males; aged 26.8 +/- 14.2 years) and caused by ambustion (AM-group, four females, four males; aged 28.1 +/- 13.8 years) were evaluated 24 h after injury. The following parameters were obtained using RCM on injured and noninjured (control) site: horny layer thickness, epidermal thickness, granular cell size, basal layer thickness.

RESULTS

Compared with the controls (12.8 +/- 2.5 microm), horny layer thickness decreased significantly to 10.6 +/- 2.1 microm in the CO-group, whereas it increased significantly to 17.8 +/- 2.8 microm in the AM-group. The epidermal thickness did not differ significantly in CO-group (47.9 +/- 2.1 microm) and AM-group (49.0 +/- 3.1 microm), however, both increased significantly compared with the controls (42.7 +/- 1.6 microm). The basal layer thickness increased more in AM-group (17.0 +/- 1.2 microm) compared to CO-group (15.4 +/- 1.1 microm). Both differed significantly compared with their controls (13.9 +/- 0.9 microm). The granular cell size increased significantly in both groups compared to the controls (721 +/- 42 microm), however, a significantly higher increase was observed in CO-group compared to AM-group (871 +/- 55 microm vs. 831 +/- 51 microm).

CONCLUSIONS

RCM evaluates significant histomorphological differences in superficial burns caused by combustion and ambustion. The term "superficial burn" should consider the underlying cause and thus supplemented by the term "combustion" or "ambustion."

Insight in human skin microcirculation using in vivo reflectance-mode confocal laser scanning microscopy

Reflectance-mode confocal laser scanning microscopy allows in vivo imaging of the human skin. We hypothesized that this high-resolution technique enables observation of dynamic changes of the cutaneous microcirculation. Twenty-two volunteers were randomly divided in two groups. Group 1 was exposed to local heating and group 2 to local cold stress. Confocal microscopy was performed prior t (0) (control), directly t (1) and 5 min t (2) after local temperature changes to evaluate quantitative blood cell flow, capillary loop diameter, and density of dermal capillaries. In group 1, blood flow increased at t (1) (75.82 +/- 2.86/min) and further at t (2) (84.09 +/- 3.39/min) compared to the control (61.09 +/- 3.21/min). The control capillary size was 9.59 +/- 0.25 microm, increased to 11.16 +/- 0.21 microm (t (1)) and 11.57 +/- 0.24 microm (t (2)). The dermal capillary density increased in t (1) (7.26 +/- 0.76/mm(2)) and t (2) (8.16 +/- 0.52/mm(2)), compared to the control (7.04 +/- 0.62/mm(2)). In group 2, blood flow decreased at t (1) (41.73 +/- 2.61/min) and increased at t (2) (83.27 +/- 3.29/min) compared to the control (60.73 +/- 2.90/min). The control capillary size was 9.55 +/- 0.25 microm, decreased at t (1) (7.78 +/- 0.26 microm) and increased at t (2) (11.38 +/- 0.26 microm). Capillary density decreased at t (1) (5.01 +/- 0.49/mm(2)) and increased at t (2) (7.28 +/- 0.53/mm(2)) compared to the control (7.01 +/- 0.52/mm(2)). Confocal microscopy is a sensitive and noninvasive imaging tool for characterizing and quantifying dynamic changes of cutaneous microcirculation on a histomorphological level.

A Comparative Pilot Study on Ultraviolet-induced Skin Changes Assessed by Noninvasive Imaging Techniques in Vivo

The effects of acute and chronic ultraviolet (UV) on the morphology of human skin have been extensively studied ex vivo by means of histological investigations. However, innovative skin imaging techniques enable visualization of micromorphological structures in vivo. We aimed to perform a correlation study evaluating in vivo dose and time dependent skin changes following solar-simulated irradiation using noninvasive techniques such as optical coherence tomography (OCT) and confocal laser scanning microscopy (CLSM). The forearms of 10 healthy subjects were exposed to 1 minimal erythema dose (MED) and 3 MED of solar-simulated radiation. Noninvasive measurements were performed before and 24 h and 72 h after UV exposures. We demonstrate definite OCT and CLSM findings obtained from UV-exposed skin, including an increase in epidermal thickness (hyperproliferation, acanthosis), a reduction in dermal reflectivity (dermal edema), an increase in brightness of the basal layer (pigmentation), and an increase in vessel diameter within the dermal papillae (vasodilatation). A moderate to strong linear association between the methods employed was observed. In conclusion, noninvasive high-resolution imaging techniques such as OCT and CLSM may be promising tools for photobiological studies aimed at assessing photoadaptive and/or phototoxic processes in vivo. However, larger studies are needed to demonstrate the applicability of the findings presented in this pilot study.