Previous attempts at classifying small graft transplants have focused mainly upon graft size and have not taken into consideration other technical factors involved in graft production that may influence the outcome of the surgery. The proposed classification attempts to consider these factors by including various technical aspects of harvesting, dissection, and placement, all of which impact the quality and quantity of the small grafts used in the procedure. By standardizing the nomenclature, as well as the description of the other factors involved in the surgery, communication between physicians and patients may be facilitated. In addition, different procedures may be more accurately studied and compared.

The blisters in the inherited disorder, Hailey-Hailey disease, may be caused by defective epidermal junctional complexes. We evaluated these structural complexes in vivo and in vitro. We induced a vesicular lesion in the apparently normal skin of a patient with Hailey-Hailey disease and studied a biopsy of this lesion by transmission electron microscopy. To determine whether acantholysis was related to a defect in the number or assembly of intercellular junctions, we cultured Hailey-Hailey disease keratinocytes in medium containing 0.1 mM Ca2+ and increased the [Ca2+] to 1.1 mM in order to induce assembly of cell-cell junctions. Keratinocytes were examined by double immunofluorescence with antibodies to the desmosome protein, desmoplakin, and the adherens junction protein, vinculin, at intervals after the increase in [Ca2+]. Characteristic Hailey-Hailey disease histopathology was observed by electron microscopy of the patient's skin after trauma, but we found no splitting of desmosomes. Based on the location, intensity, and rate of change of immunofluorescent staining, Hailey-Hailey and normal keratinocytes did not differ in their ability to assemble desmosomes and adherens junctions. Furthermore, we observed no significant morphologic differences between normal and Hailey-Hailey keratinocytes cultured in low and high [Ca2+]-containing media; Hailey-Hailey cells contained abundant normal-appearing desmosomes in 1.1 mM [Ca2+]. Since Hailey-Hailey disease keratinocytes can assemble normal-appearing adherens junctions and desmosomes in vitro, the functional defect may not lie in assembly of cell-cell adhering junctions, or additional perturbation may be required to expose the defect.

No abstract

The cells of the adult follicular dermal papilla retain a powerful hair-inductive capacity acquired during embryonic hair morphogenesis. This inductive capacity is the basis of a cell therapy called follicular cell implantation in which dermal papilla cells from a small number of donor follicles are expanded in culture and then implanted into a bald region of scalp. In this manner, many new follicles can be formed from the cells of a few.KEYWORDS: Hair, regenerative medicine, hair cloning, dermal papilla, cell therapyThe dermal papilla (DP) is comprised of fibroblast-like cells that are almost unique among adult mammalian cells in that they possess an inductive property that they acquired in the embryo during hair morphogenesis, a property they maintain throughout adult life. This property is the basis of an emerging cell therapy called follicular cell implantation (FCI) 1 in which dermal papilla cells taken from a few follicles are expanded in culture and then implanted into the skin to induce the formation of many new follicles.The idea behind the DP as a cell therapy to treat hair loss is not new. 2 The DP was long assumed to play a critical role in follicle morphogenesis, 3 and the first direct evidence was the demonstration in the 1960s that transplanted dermal papillae could induce the formation of new follicles. Borrowing from experiments with avian feather papillae, Cohen 4 transplanted dermal papillae into rat ear and observed epidermal downgrowths, the beginnings of new follicles. Oliver 5 placed dermal papillae into the base of whisker follicles that were truncated and thereby rendered unable to regenerate, and the transplanted papillae were able to induce the complete regrowth of those follicles. These experiments first revealed the remarkable hair-inductive power of the adult follicle dermal papilla.Although the concept behind FCI is simple, four decades have passed since the Cohen and Oliver experiments without the introduction of a clinically useful treatment. Here we describe the conceptual and experimental framework behind this therapy, the technical barriers to its development, and how recent advances have brought the technology forward such that FCI may become available in the coming years. BIOLOGY OF THE HAIR FOLLICLEThe hair follicle mainly consists of an epithelial component and a mesenchymal component. The epithelial component is contiguous with interfollicular epidermis and is comprised of specialized keratinocytes (see Fig. 1). Epidermal stem cells reside in the bulge region of the follicle, 6 a portion of the outer root sheath near the attachment point for the arrector pili muscle. The progeny of stem cells migrate down the outer root sheath 7 to the matrix, and from within the matrix they differentiate into the various concentric layers that comprise the inner root sheath and hair shaft. The dermal papilla is a ball of fibroblast-like cells in the lower part of the follicle and is connected to the dermal sheath through a short stalk at its base. KeratinocyteHair Restoration:

The deeper level of this peel explains the improved cosmetic outcome and greater eradication of actinic keratoses. This treatment is particularly well suited for patients with extensive photodamage and widespread actinic keratoses.