Hair growth
In vivo cytokine and receptor gene expression during the rat hair growth cycle. Analysis by semi-quantitative RT-PCR.

Little JC, Redwood KL, Granger SP, Jenkins G.

Unilever Research, Sharnbrook, Bedford, UK.

A number of cytokines have previously been localised within the developing and adult hair follicle, however, the role they play in producing a mature hair follicle remains unknown. In an attempt to identify dermal papilla specific cytokines and thus those that may have an important controlling role, cytokine gene expression profiles, obtained by reverse transcriptase-polymerase chain reaction (RT-PCR), were compared between whole anagen rat hair follicles, passage 2 dermal papillae (a cell type with hair inductive capacity), and footpad fibroblasts (a non-hair inducing cell type). Based on this qualitative data, we were unable to identify a dermal papilla specific gene. The analysis of the pattern and timing of cytokine gene expression during the hair cycle is likely to be more informative. A semi-quantitative RT-PCR technique was therefore developed for studying trends in the level of in vivo expression of the following cytokines and their receptors from early anagen to early catagen in the rat hair growth cycle: insulin-like growth factor I, transforming growth factor beta 1, tumour necrosis factor, and basic fibroblast growth factor. These genes were found to be differentially expressed and this was correlated with their possible functions in controlling the hair growth cycle, providing valuable insights into the role of cytokines in regulating the hair growth process.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8889467&dopt=Abstract alopecia, hair loss hair growth



Hair growth
Fibroblast growth factor signalling in the hair growth cycle: expression of the fibroblast growth factor receptor and ligand genes in the murine hair follicle.

Rosenquist TA, Martin GR.

Department of Anatomy, University of California at San Francisco 94143-0452, USA.

Using RNA in situ hybridization analysis, we have characterized the expression domains of the four known members of the FGF receptor-tyrosine kinase gene family in the murine hair follicle at various stages of the hair growth cycle. During anagen, we detected Fgfr1 RNA in the dermal papilla, Fgfr2 RNA in hair matrix cells near the dermal papilla, Fgfr3 RNA in pre-cuticle cells in the periphery of the hair bulb, and Fgfr4 RNA in cells in the periphery of the hair bulb and also in the inner and outer root sheath in the lower half of the follicle neck. No RNA expression of these genes was detected during late catagen or telogen. We have previously shown that Fgf5 is expressed in the outer root sheath in the transient portion of the follicle (Hebert et al. [1994] Cell 78:1017-1025). In the present study we have also assayed for the expression of six other members of the FGF ligand gene family, Fgf3, Fgf4, Fgf6, Fgf7, Fgf8, and Fgf9. Among these FGF genes, only Fgf7 was found to be expressed in the hair follicle. Fgf7 RNA is localized to the dermal papilla during anagen, but expression is down-regulated by the late-anagen VI stage. We have also demonstrated that addition of FGF5 protein to the culture medium changes the behavior of dermal papilla cells in vitro, indicating that they are capable of responding to FGF5. Together with previously published data, these results provide a complete analysis of FGF ligand and FGF receptor-tyrosine kinase gene expression in the hair follicle, and suggest that FGF signalling may have several functions in the hair growth cycle.

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Hair growth
An estrogen receptor pathway regulates the telogen-anagen hair follicle transition and influences epidermal cell proliferation.

Oh HS, Smart RC.

Department of Toxicology, North Carolina State University, Raleigh 27695-7633, USA.

The hair follicle is a cyclic, self renewing epidermal structure which is thought to be controlled by signals from the dermal papilla, a specialized cluster of mesenchymal cells within the dermis. Topical treatments with 17-beta-estradiol to the clipped dorsal skin of mice arrested hair follicles in telogen and produced a profound and prolonged inhibition of hair growth while treatment with the biologically inactive stereoisomer, 17-alpha-estradiol, did not inhibit hair growth. Topical treatments with ICI 182,780, a pure estrogen receptor antagonist, caused the hair follicles to exit telogen and enter anagen, thereby initiating hair growth. Immunohistochemical staining for the estrogen receptor in skin revealed intense and specific staining of the nuclei of the cells of the dermal papilla. The expression of the estrogen receptor in the dermal papilla was hair cycle-dependent with the highest levels of expression associated with the telogen follicle. 17-beta-Estradiol-treated epidermis demonstrated a similar number of 5-bromo-2'-deoxyuridine (BrdUrd) S-phase cells as the control epidermis above telogen follicles; however, the number of BrdUrd S-phase basal cells in the control epidermis varied according to the phase of the cycle of the underlying hair follicles and ranged from 2.6% above telogen follicles to 7.0% above early anagen follicles. These findings indicate an estrogen receptor pathway within the dermal papilla regulates the telogen-anagen follicle transition and suggest that diffusible factors associated with the anagen follicle influence cell proliferation in the epidermis.

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Hair growth
Hair growth in neonatally undernourished rats.

Salas M, Pulido S, Torrero C, Regalado M, Loranca A.

Centro de Neurobiologia, Universidad Nacional Autonoma de Mexico. D.F., Mexico.

Interaction between neonatal undernutrition and the increased self-grooming activity upon hair growth of several body areas was analyzed in rats of 10, 20 and 30 days of age. Light microscopic observations on methylene blue impregnated hairs showed that these perinatal influences delayed the growth of hair follicles and thickness and length of hair measurements of the head and thoracic areas. The hair growth of lateral abdominal regions was less affected. Data suggest that hair alterations are primarily related to food deprivation since hair follicle measures of all skin areas were more affected than the distal hair measurements. Moreover, the distribution of impaired hair growth on different body areas correlates well with the increased self-grooming components associated to neonatal undernourishment.

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Hair growth
Cytokines and growth factors influence hair growth in vitro. Possible implications for the pathogenesis and treatment of alopecia areata.

Hoffmann R, Eicheler W, Huth A, Wenzel E, Happle R.

Department of Dermatology, Philipp University, Marburg, Germany.

Factors that influence the growth of the anagen hair follicle or initiate the switch to a catagen growth pattern have so far not been definitely determined, but there is increasing evidence that cytokines and growth factors play an important role during these processes. Recently we detected an aberrant in situ expression pattern of cytokines of the Th1 type (IFN gamma, IL-2) plus IL-1 beta expression in untreated alopecia areata (AA), and a switch to high levels of IL-10 TGF-beta 1 expression after successful treatment with the contact allergen diphenylcyclopropenone (DCP). Hence the question arose as to whether cytokines are able to arrest hair growth and whether IL-10 or TGF beta 1 have the capacity to antagonize this process. Using whole-organ cultures of microdissected human hair follicles we studied the effect of a panel of cytokines and growth factors on hair growth and on the gross morphology of the hair follicles in vitro. IL-2, IL-10 and IFN-gamma had no effect in this regard, whereas TGF beta 1 partially inhibited hair growth and EGF, TNF alpha and IL-1 beta completely abrogated it. EGF and TNF alpha induced the formation of a club-like hair follicle, similar to catagen morphology of the hair bulb, whereas hair follicles grown in the presence of IL-1 beta or TGF beta 1 showed no particular morphological changes. We conclude that cytokines and growth factors are pivotal regulators of hair growth at least in vitro. IL-1 is suggested as playing an important role during the pathogenesis of AA. Possible mediators of therapeutic contact dermatitis (IL-10, TGF beta 1, TNF alpha, PGE2) are, at least in vitro, not able to antagonize the IL-1 beta-triggered hair growth inhibition. Therefore, we infer that these mediators rather "modulate' the immune response in AA.

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Hair growth
Clinical and cost comparison of three postoperative skin preparation protocols in CABG patients.

De Geest S, Kesteloot K, Adriaenssen G, Lenaerts K, Thelissen MJ, Mekers G, Sergeant P, Daenen W.

Department of Health Services and Nursing Research, School of Public Health, Catholic University of Leuven, Belgium.

This descriptive pilot study includes a clinical and cost comparison of three preoperative skin preparation protocols (razor, clipper, and depilatory cream, in combination with whole body disinfection) in 82 patients undergoing coronary artery bypass graft (CABG) surgery. The clinical research protocol included an evaluation of body surface area, index of body hair growth, depilatory effect, skin integrity after depilation, and side effects of body disinfection with chlorhexidine solution, as well as protocol-specific evaluation criteria. The cost comparison was performed by keeping a record of the materials used and the workload for each separate activity associated with the three preoperative skin preparation protocols. Material and labor costs were calculated for each of the different aspects of the protocols. Clinical evaluation revealed that the clipper protocol (if necessary, in combination with cream depilation) is most convenient for depilation of patients with heavy hair growth. The depilatory cream protocol is an appropriate method to depilate patients with slight or moderate hair growth. The razor method should be eliminated from clinical practice due to previous documented evidence of an associated increased risk of postoperative wound infection. Cost calculations revealed that the median hospital cost (standardized for differences in hair growth index, working hours and nurse qualification levels) of the razor, clipper, and cream protocols is $6.13, $9.84, and $8.16 (U.S. dollars), respectively. In 1995, yearly raw (i.e. non-standardized) hospital costs for the three procedures were $14,402, $16,114, and $16,765, respectively, with 708 CABG procedures performed. Although changing to a clipper and/or cream protocol may be associated with an initial, although moderate, increase in hospital costs, compared to the razor method, substantial cost savings could be expected long-term. The superiority of these protocols is primarily due to a decreased incidence of postoperative wound infections, as compared to that associated with the razor protocol.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8969001&dopt=Abstract alopecia, hair loss hair growth