Hair Curvature: A Natural Dialectic and Review

March 2014 in “ Biological reviews/Biological reviews of the Cambridge Philosophical Society ”

J. Nissimov, Amala Chaudhuri

Studysummary This study introduces the multiple papillary centres model, offering a new explanation for hair twisting by combining known hair morphology features with differential growth rates caused by dermal papillae. Our plain-language summary of this paper — not a Tressless recommendation.

The article explored the genetic and physical mechanisms behind hair curvature, proposing a multiple papillary centres (MPC) model to explain hair twisting. This model suggested that differential growth rates in hair cortical material, induced by partially or completely separated dermal papillae within single follicles, could account for various hair forms. The study reviewed evidence supporting the involvement of the Wnt and mTOR pathways in hair bending and twisting, respectively. It also considered epithelial-to-mesenchymal (EMT) and mesenchymal-to-epithelial (MET) transitions as mechanisms influencing hair growth and morphology. The MPC model aimed to provide a unified framework for understanding hair growth and development from neural-crest stem cell (NCSC) lineages to differentiated hair follicle (HF) cell types.

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This study cataloged human type II hair keratins, detailing their expression and differentiation roles in hair follicles and comparing them with type I keratins to explore keratin-pairing principles.

research The Transcriptional Repressor CDP (Cutl1) Is Essential for Epithelial Cell Differentiation of the Lung and the Hair Follicle

165 citations , September 2001 in “Genes & development”

This study found that Cutl1 mutant mice experienced retarded lung differentiation and abnormal hair follicle morphogenesis, indicating the vital role of CDP in lung development and hair follicle cell-lineage specification.

research Control of Hair Growth and Follicle Size by VEGF-Mediated Angiogenesis

520 citations , February 2001 in “Journal of Clinical Investigation”

This study found that VEGF significantly enhances perifollicular vascularization during the hair growth phase, accelerating hair regrowth and increasing follicle and hair size, while its inhibition retards hair growth.

research Morphogenesis and Renewal of Hair Follicles from Adult Multipotent Stem Cells

949 citations , January 2001 in “Cell”

This study demonstrated that multipotent stem cells in adult mice whisker follicles migrate to produce whisker growth, and that this process requires precise control of stem cell trafficking.

research Two Distinct Signaling Pathways in Hair Cycle Induction: Stat3-Dependent and Independent Pathways

73 citations , November 2000 in “Proceedings of the National Academy of Sciences of the United States of America”

This study demonstrated that anagen can be induced in Stat3-disrupted mice, suggesting that both Stat3-dependent and independent pathways, possibly involving PKC, mediate hair cycle progression with required PI3K activation.

research Modeling the Dynamics of Human Hair Cycles by a Follicular Automaton

67 citations , July 2000 in “Proceedings of the National Academy of Sciences”

This study developed a follicular automaton model that simulates human hair cycle dynamics and can replicate hair pattern changes associated with diffuse or androgenetic alopecia.

research Differences in Hair Follicle Dermal Papilla Volume Are Due to Extracellular Matrix Volume and Cell Number: Implications for the Control of Hair Follicle Size and Androgen Responses

231 citations , December 1999 in “Journal of Investigative Dermatology”

This study found that the volume of a hair follicle's dermal papilla is strongly correlated with its size, primarily due to the number of cells it contains and the volume of extracellular matrix.

research Induction of the Hair Growth Phase in Postnatal Mice by Localized Transient Expression of Sonic Hedgehog

231 citations , October 1999 in “Journal of Clinical Investigation”

This study found that administering an adenovirus vector to increase Sonic hedgehog gene expression in mouse skin accelerated the transition of hair follicles into the growth phase, promoting hair growth.

research The Biology of Hair Follicles

1113 citations , August 1999 in “The New England Journal of Medicine”

This article discusses the biologic and psychosocial significance of hair, the current limitations in hair growth drugs, and anticipates future therapies based on advancing hair follicle research.

research Manipulation of Outer Root Sheath Cell Survival Perturbs the Hair-Growth Cycle

37 citations , July 1999 in “The EMBO Journal”

Overexpression of certain genes can shorten hair by disrupting the hair-growth cycle.

research Ultrastructural Localization of S100A3, a Cysteine-Rich, Calcium Binding Protein, in Human Scalp Hair Shafts Revealed by Rapid-Freezing Immunocytochemistry

40 citations , April 1999 in “Journal of Histochemistry & Cytochemistry”

In this study, the researchers identified the specific subcellular localization of the protein S100A3 in the endocuticle and cortex of human hair shafts.

research WNT Signaling in the Control of Hair Growth and Structure

271 citations , March 1999 in “Developmental biology”

This study reveals that overexpression of Wnt3 in transgenic mouse skin leads to a short-hair phenotype and cyclical balding due to structural defects in hair shafts, highlighting a role for WNT signaling in hair growth regulation.

research Gene Expression of Mouse S100A3, a Cysteine-Rich Calcium-Binding Protein, in Developing Hair Follicle

40 citations , November 1998 in “The journal of investigative dermatology/Journal of investigative dermatology”

This study found that the S100A3 gene is exclusively expressed in hair follicle cells differentiating into hair shaft components in mice, suggesting its important role in hair formation.

research Angora Mouse Mutation: Altered Hair Cycle, Follicular Dystrophy, Phenotypic Maintenance of Skin Grafts, and Changes in Keratin Expression

69 citations , May 1997 in “Veterinary Pathology”

This study found that the angora mouse mutation prolongs the anagen phase, resulting in excessively long hair and follicular abnormalities, without involving circulating hair cycle factors.

research The Role of Keratin Proteins and Their Genes in the Growth, Structure, and Properties of Hair

228 citations , January 1997 in “Birkhäuser Basel eBooks”

This article integrates existing literature on hair follicle structure and formation at the cellular and molecular level, reporting no new findings.

research Dermal-Epidermal Interactions in Hair Follicle Development and Maintenance

114 citations , October 1996 in “Dermatologic clinics”

This chapter reviews laboratory models used for studying alopecia therapies but provides no new experimental findings.

research Growth Factors in Hair Organ Development and the Hair Growth Cycle

90 citations , October 1996 in “Dermatologic Clinics”

This study found that red ginseng oil may enhance hair growth and protect skin from UV damage in mouse models by promoting regenerative processes and reducing inflammation.

research The Proximal Promoter of the Human Transglutaminase 3 Gene

105 citations , February 1996 in “Journal of biological chemistry/The Journal of biological chemistry”

In this study, sequences upstream of the TGM3 gene were found to regulate epithelial-specific gene expression in keratinocytes, suggesting potential applications in gene therapy.

research Androgen Induction of Follicular Epithelial Cell Growth Is Mediated via Insulin-like Growth Factor-I from Dermal Papilla Cells

173 citations , July 1995 in “Biochemical and biophysical research communications”

This study suggests that IGF-I may mediate androgen-induced hair growth in outer root sheath cells cocultured with beard dermal papilla cells.

research Ultrastructural Visualization of Cross-Linked Protein Features in Epidermal Appendages

43 citations , July 1994 in “Journal of Cell Science”

This study found that the extraction-resistant structures in hair, feathers, and hagfish teeth are due to ε-(γ-glutamyl)lysine cross-linked proteins, emphasizing their role in maintaining the integrity of these materials.

research Effects of Epidermal Growth Factor on the Morphology and Patterns of DNA Synthesis in Isolated Human Hair Follicles

94 citations , February 1994 in “The journal of investigative dermatology/Journal of investigative dermatology”

This study concluded that epidermal growth factor may induce a 'catagen-like' phase in human hair follicles by disrupting normal cellular proliferation and migration patterns.

research Dynamic Expression Patterns of Tenascin, Proteoglycans, and Cell Adhesion Molecules During Human Hair Follicle Morphogenesis

67 citations , February 1994 in “Developmental dynamics”

This study analyzed the distribution of adhesion molecules and extracellular matrix components in human fetal skin, suggesting their roles in hair follicle development.

Melanogenesis Is Coupled to Murine Anagen: Toward New Concepts for the Role of Melanocytes and the Regulation of Melanogenesis in Hair Growth

research Melanogenesis Is Coupled to Murine Anagen: Toward New Concepts for the Role of Melanocytes and the Regulation of Melanogenesis in Hair Growth

210 citations , July 1993 in “The journal of investigative dermatology/Journal of investigative dermatology”

This review discusses the role of intrinsic skin signals, rather than serum signals, in regulating melanin synthesis and hair pigmentation, but reports no new experimental data.

research The Structure of Human Trichohyalin: Potential Multiple Roles as a Functional EF-Hand-Like Calcium-Binding Protein, a Cornified Cell Envelope Precursor, and an Intermediate Filament-Associated (Cross-Linking) Protein

161 citations , June 1993 in “Journal of Biological Chemistry”

This study suggests that human trichohyalin may function as a flexible rod linking keratin intermediate filaments and as a scaffold protein in hair follicle and epidermis cell envelopes.

research Telogen Effluvium: A Comprehensive Review

214 citations , March 1993 in “Archives of Dermatology”

This article proposes five different mechanisms for telogen effluvium, supported by clinical findings, based on changes in different phases of the hair cycle.

research The Secret Life of the Hair Follicle

745 citations , February 1992 in “Trends in genetics”

This article describes the potential role of various growth factors and molecules in regulating mammalian hair follicle development but does not present new experimental results.

research Hair, Wool, Quill, Nail, Claw, Hoof, and Horn

50 citations , January 1986

research The Unit Area Trichogram in the Assessment of Androgen-Dependent Alopecia

90 citations , October 1983 in “British Journal of Dermatology”

This study found that individuals with androgenic alopecia have an increased number of thin hairs (less than 40 microns in diameter) per cm², which may affect their clinical appearance.

research Hair Diameter in Female Baldness

63 citations , October 1972 in “British Journal of Dermatology”

Women with thinning hair have thinner hair strands than women without hair loss.

research Nutritional Factors Influencing Hair and Wool Growth

25 citations , January 1958 in “Elsevier eBooks”