Intradermal Indocyanine Green for In Vivo Fluorescence Laser Scanning Microscopy of Human Skin: A Pilot Study

BACKGROUND: In clinical diagnostics, as well as in routine dermatology, the increased need for non-invasive diagnosis is currently satisfied by reflectance laser scanning microscopy. However, this technique has some limitations as it relies solely on differences in the reflection properties of epidermal and dermal structures. To date, the superior method of fluorescence laser scanning microscopy is not generally applied in dermatology and predominantly restricted to fluorescein as fluorescent tracer, which has a number of limitations. Therefore, we searched for an alternative fluorophore matching a novel skin imaging device to advance this promising diagnostic approach. METHODOLOGY/PRINCIPAL FINDINGS: Using a Vivascope®-1500 Multilaser microscope, we found that the fluorophore Indocyanine-Green (ICG) is well suited as a fluorescent marker for skin imaging in vivo after intradermal injection. ICG is one of few fluorescent dyes approved for use in humans. Its fluorescence properties are compatible with the application of a near-infrared laser, which penetrates deeper into the tissue than the standard 488 nm laser for fluorescein. ICG-fluorescence turned out to be much more stable than fluorescein in vivo, persisting for more than 48 hours without significant photobleaching whereas fluorescein fades within 2 hours. The well-defined intercellular staining pattern of ICG allows automated cell-recognition algorithms, which we accomplished with the free software CellProfiler, providing the possibility of quantitative high-content imaging. Furthermore, we demonstrate the superiority of ICG-based fluorescence microscopy for selected skin pathologies, including dermal nevi, irritant contact dermatitis and necrotic skin. CONCLUSIONS/SIGNIFICANCE: Our results introduce a novel in vivo skin imaging technique using ICG, which delivers a stable intercellular fluorescence signal ideal for morphological assessment down to sub-cellular detail. The application of ICG in combination with the near infrared laser opens new ways for minimal-invasive diagnosis and monitoring of skin disorders

Quantification of skin lesions with a 3D stereovision camera system: Validation and clinical applications

Background/purpose: Three-dimensional (3D) imaging of the skin is a challenging technique. A new 3D digital camera system has been developed that enables 3D reconstruction of the skin and subsequently allows volumetric quantification. Herein we present validation data on calibrated phantoms and the clinical application of this technology. Methods: Absolute and relative geometric 3D measurements were validated with a static imaging phantom manufactured by a metrology institution and a dynamic imaging phantom adjustable for different volume quantities, respectively. Consecutively, in a clinical study, 3D baseline and follow up images from 27 basal cell carcinomas under topical therapy were captured for volumetric analysis. Results: Validation experiments have demonstrated an average accuracy for surface position of 55 μm and a precision of 8 μm, as well as excellent correlation (0.999) between injected and measured volumes. The geometric baseline analysis of 27 basal cell carcinomas exhibited a high correlation and agreement between 2D and 3D surface measurements. Under topical therapy, it was possible to gain statistically significant differences between verum- and vehicle-treated basal cell carcinomas when analyzing geometric measurements of 3D volume (P = 0.01) and 3D surface (P = 0.001). Conclusion: In our study we were able to demonstrate that this newly developed 3D camera system offers a precise objective dimensional representation of the skin. This technique is easily applicable and sensitive enough to measure small differences in area and volume before and after intervention. © 2012 John Wiley & Sons A/S

The PKC inhibitor AEB071 may be a therapeutic option for psoriasis

PKC isoforms t, α, and β play fundamental roles in the activation of T cells and other immune cell functions. Here we show that the PKC inhibitor AEB071 both abolishes the production of several cytokines by activated human T cells, keratinocytes, and macrophages in vitro and inhibits an acute allergic contact dermatitis response in rats. To translate these findings into humans, single and multiple ascending oral doses of AEB071 were administered to healthy volunteers and patients with psoriasis, respectively. AEB071 was well tolerated with no clinically relevant laboratory abnormalities. Ex vivo stimulation of lymphocytes from subjects exposed to single doses of AEB071 resulted in a dose-dependent inhibition of both lymphocyte proliferation and IL2 mRNA expression. Clinical severity of psoriasis was reduced up to 69% compared with baseline after 2 weeks of treatment, as measured by the Psoriasis Area Severity Index (PASI) score. The improvement in psoriasis patients was accompanied by histological improvement of skin lesions and may be partially explained by a substantial reduction of p40+ dermal cells, which are known to mediate psoriasis. These data suggest that AEB071 could be an effective novel treatment regimen for psoriasis and other autoimmune diseases, and that AEB071 warrants long-term studies to establish safety and efficacy

George Tucker photograph, Southampton Fair, 1955.

Photograph of Alf Whitelegg and Son's steam 3 Abreast, taken April 1955 full view building up, centre on gantry. Ex G. A. Whittle. G1