In vivo imaging of Malassezia yeasts on human skin using confocal laser scanning microscopy

Abstract

Fiber-based confocal laser scanning microscopy affords a vast field of application in medical research and clinical practice. The application of fluorescent dye allows real-time imaging of yeasts of the genus Malassezia on human skin in vivo. An Ar + -laser is used to excite the fluorescent food dye sodium fluorescein at 488 nm. Its emission is simultaneously detected in the spectral region from 500-600 nm. Topically applied fluorescein labels fungal microstructures in native habitat. Cumulative intradermal injection of the same dye enables a subsurface view of the underlying cutaneous area. In the present paper, we report the ability of the combination of in vivo confocal microscopy and sodium fluorescein application to produce real-time and high-resolution images of fungal structures on human skin. The obtained confocal images demonstrate the micro architecture of superficial Malassezia yeasts and corneocytes in horizontal plane. Taxonomic classification into different Malassezia species and observation of their colonisation patterns in native milieu brings new conclusions to fungal skin behaviour and diseases. We demonstrate advantages in clinical investigation practice over traditional laboratory routine using this non-invasive imaging tool. The described method opens new promising prospects and the possibility for further studies in fungal research.

The role of the microbiome in scalp hair follicle biology and disease

“…This is most likely due to the fact that sebaceous glands exhibit lower activity and different sebum composition before puberty . Yeasts were also identified in the infundibulum by light and electron microscopy in biopsy samples and in vivo on the scalp by confocal laser scanning microscopy …”

Malassezia species and their associated skin diseases

“…The histopathological findings of lesional skin biopsy specimens in PV demonstrated that follicular abnormalities included atrophy, degeneration, miniaturization, keratotic plugs and infundibular dilatation, as well as a slight hyperkeratosis and mild acanthosis. Malassezia is known to reside within the infundibulum of the hair follicle, suggesting that PV is a hair follicular centric infectious disease. Consistent with this hypothesis, hair loss and/or thinning within PV lesions were reported .…”

Application of in vivo Laser Scanning Microscopy to Visualise the Penetration of a Fluorescent Dye in Solution and in Liposomes into the Skin after Pre-Treatment with Microneedles

“…CLSM can be applied both in vitro and in vivo. For example, Meyer et al imaged Malassezia yeasts on living human cutaneous tissue using sodium fluorescein to label both the skin surface and the micro-flora structures with this method (Meyer et al, 2005). As well as visualising the penetration of substances into the skin, the effect of encapsulation of a dye into particles on the penetration pathways can be studied (Ossadnik et al, 2006), and CLSM can be used to study morphological changes of the skin (Dietterle et al, 2008, Eichert et al, 2010, Meyer et al, 2007.…”