The structure and function of the skin details the individual components of the epidermis, dermis, and their roles in normal skin health. The individual cell types in the epidermis, the different epidermal layers, and the roles of the keratinocyte are explained. The epidermis and dermis, and their important relation to each other through the dermoepidermal junction are described. The dermal adnexal structures of hair follicles (pilosebaceous units), sweat glands, and nerves are all considered. The functions of skin and barrier function are also listed. Rare but important causes of disordered sweating (hyperhidrosis and hypohidrosis) are described. In addition, presentations of hyperhidrosis are discussed.

Structure and function of the skin

Nanoparticle-Induced Autophagy in Biomedical Research Karen Peynshaert,†,‡ Bella B. Manshian, Freya Joris,†,‡ Kevin Braeckmans,†,‡ Stefaan C. De Smedt,*,†,∥ Jo Demeester,† and Stefaan J. Soenen*,†,§ †Lab of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, ‡Centre for Nanoand Biophotonics, and Ghent Research Group on Nanomedicine, Ghent University, B9000 Ghent, Belgium Biomedical MRI Unit/MoSAIC, Department of Imaging and Pathology, Faculty of Medicine, Catholic University of Leuven, B3000 Leuven, Belgium

Exploiting intrinsic nanoparticle toxicity: the pros and cons of nanoparticle-induced autophagy in biomedical research.

Abstract In the past decades, much attention has been paid to toxicity assessment of nanoparticles prior to clinical and biological applications. While in vitro studies have been increasing constantly, in vivo studies of nanoparticles have not established a unified system until now. Predictive models and validated standard methods are imperative. This review summarizes the current progress in approaches assessing nanotoxicity in main systems, including the hepatic and renal, gastrointestinal, pulmonary, cardiovascular, nervous, and immune systems. Histopathological studies and specific functional examinations in each system are elucidated. Related injury mechanisms are also discussed.

https://www.degruyter.com/downloadpdf/j/ntrev.2017.6.issue-3/ntrev-2016-0047/ntrev-2016-0047.xml

Toxicity assessment of nanoparticles in various systems and organs

The majority of commercial sunblock preparations use organic or inorganic ultraviolet (UV) filters. Despite protecting against cutaneous phototoxicity, direct cellular exposure to UV filters has raised a variety of health concerns. Here, we show that the encapsulation of padimate O (PO)—a model UV filter—in bioadhesive nanoparticles (BNPs) prevents epidermal cellular exposure to UV filters while enhancing UV protection. BNPs are readily suspended in water, facilitate adherence to the stratum corneum without subsequent intra-epidermal or follicular penetration, and their interaction with skin is water resistant yet the particles can be removed via active towel drying. Although the sunblock based on BNPs contained less than 5 wt% of the UV-filter concentration found in commercial standards, the anti-UV effect was comparable when tested in two murine models. Moreover, the BNP-based sunblock significantly reduced double-stranded DNA breaks when compared with a commercial sunscreen formulation. A water-resistant sunblock based on bioadhesive nanoparticles encapsulating a model ultraviolet filter at low concentrations adheres to the stratum corneum without subsequent intra-epidermal or follicular penetration.

/pdf/a-sunblock-based-on-bioadhesive-nanoparticles-41kpuc44xi.pdf

A Sunblock Based On Bioadhesive Nanoparticles

Integrating biological imaging into early stages of the drug discovery process can provide invaluable readouts of drug activity within complex disease settings, such as cancer. Iterating this approach from initial lead compound identification in vitro to proof-of-principle in vivo analysis represents a key challenge in the drug discovery field. By embracing more complex and informative models in drug discovery, imaging can improve the fidelity and statistical robustness of preclinical cancer studies. In this Review, we highlight how combining advanced imaging with three-dimensional systems and intravital mouse models can provide more informative and disease-relevant platforms for cancer drug discovery.

Marina Le Lamer

Papers

The effect of formulation on the penetration of coated and uncoated zinc oxide nanoparticles into the viable epidermis of human skin in vivo