One challenge faced by stem cell biologists is the bioengineering of an organ. Ehama et al. (2007, this issue) used cells derived from human and rodent epidermis and dermal papilla to reconstitute hair-follicle mini-organs. Some result in hair follicles; others are hair follicle-like. The challenge calls for the development of a set of criteria to define a hair follicle so that bioengineered pr...

The dermal papilla is a cluster of mesenchymal cells located at the base of the hair follicle which have a number of important roles in the regulation of hair growth. As a consequence, in vitro models of these cells are widely used to study the molecular mechanisms which underlie hair follicle induction, growth and maintenance. While dermal papilla from rodent hair follicles can be digested pri...

Hair can be engineered at different levels--its structure and surface--through modification of its constituent molecules, in particular proteins, but also the hair follicle (HF) can be genetically altered, in particular with the advent of siRNA-based applications. General aspects of hair biology are reviewed, as well as the most recent contributions to understanding hair pigmentation and the re...

Here, we sketch why significant progress in the as yet very unsatisfactory pharmacological management of hair loss demands more rational strategies for ‘hair drug’ development, which effectively target defined key events in hair follicle cycling and transformation. Chiefly, drugs need to be identified that serve as inhibitors of catagen, exogen and/or the terminal-to-vellus transformation, or t...

Hearing loss is the most common form of sensory impairment in humans and is frequently progressive in nature. Here we link a previously uncharacterized gene to hearing impairment in mice and humans. We show that hearing loss in the ethylnitrosourea (ENU)-induced samba mouse line is caused by a mutation in Loxhd1. LOXHD1 consists entirely of PLAT (polycystin/lipoxygenase/alpha-toxin) domains and...

This paper reviews the current knowledge about human hair photodamage and the photodegradation mechanisms proposed in the literature. It is shown that there are still a number of questions without answer regarding this issue. For example, a better understanding of the hair structural changes caused by different radiation wavelengths is still lacking. We also find controversies about the effects...

We present data on the carbon (δ(13)C), nitrogen (δ(15)N) and sulfur (δ(34)S) isotope ratios of human hair collected in the central portions of the USA. These elements are incorporated into hair from the diet and thus provide a record of dietary inputs that may also document geospatial patterns. We detected regional differences in hair δ(34)S values across the USA, with the lowest values in the...