Hair Bulb Research Articles

Vasoactive intestinal peptide, whose receptor-mediated signalling may be defective in alopecia areata, provides protection from hair follicle immune privilege collapse.

Alopecia areata (AA) is an autoimmune disorder whose pathogenesis involves the collapse of the relative immune privilege (IP) of the hair follicle (HF). Given that vasoactive intestinal peptide (VIP) is an immunoinhibitory neuropeptide released by perifollicular sensory nerve fibres, which play a role in IP maintenance, it may modulate human HF-IP and thus be therapeutically relevant for AA. To answer the following questions: Do human HFs express VIP receptors, and does their stimulation protect from or restore experimentally induced HF-IP collapse? Is VIP signalling defective in AA HFs? Firstly, VIP and VIP receptor (VPAC1, VPAC2) expression in human scalp HFs and AA skin was assessed. In HF organ culture, we then explored whether VIP treatment can restore and/or protect from interferon-γ-induced HF-IP collapse, assessing the expression of the key IP markers by quantitative (immuno-)histomorphometry. Here we provide the first evidence that VIP receptors are expressed in the epithelium of healthy human HFs at the gene and protein level. Furthermore, VIP receptor protein expression, but not VIP(+) nerve fibres, is significantly downregulated in lesional hair bulbs of patients with AA, suggesting defects in VIP receptor-mediated signalling. Moreover, we show that VIP protects the HF from experimentally induced IP collapse invitro, but does not fully restore it once collapsed. These pilot data suggest that insufficient VIP receptor-mediated signalling may contribute to impairing HF-IP in patients with AA, and that VIP is a promising candidate 'HF-IP guardian' that may be therapeutically exploited to inhibit the progression of AA lesions.

12-O-tetradecanoylphorbol-13-acetate activates hair follicle melanocytes for hair pigmentation via Wnt/β-catenin signaling

Melanocyte stem cells (McSCs) undergo cyclical activation and quiescence together with hair follicle stem cells (HFSCs). This process is strictly controlled by the autonomous and extrinsic signaling environment. However, the modulation of factors important for the activation of McSCs for hair pigmentation remains unclear. 12-O-tetradecanoylphorbol-13-acetate (TPA) mimics vital signaling pathways involved in melanocyte growth and melanogenesis in vitro. To investigate whether TPA regulates quiescent McSCs for hair pigmentation, we topically smeared TPA on 7-week-old mouse dorsal skin and found that TPA stimulated hair growth and hair matrix pigmentation. These changes were associated with a significant increase in the number of hair bulb melanocytes. Moreover, in the TPA-treated group, hair bulge McSCs and hair bulb melanoblasts actively proliferated. At the molecular level, nuclear β-catenin, a key factor of Wnt/β-catenin signaling, was highly synthesized in melanocytes and keratinocytes in TPA-induced hair bulbs. Inhibition of Wnt/β-catenin signaling by injecting Dickkopf1 plasmids into TPA-treated skin decreased hair matrix pigmentation and inhibited the proliferation and differentiation of McSCs. Our findings suggest that the topical application of TPA stimulates the proliferation and differentiation of McSCs and their progeny for hair matrix pigmentation by activating Wnt/β-catenin signaling. This might provide a useful experimental model for the study of signals controlling the activation of McSCs.

Loose Anagen Syndrome: A Retrospective Chart Review of 37 Cases.

Loose anagen syndrome (LAS) is a disorder of abnormal anchorage of the hair to the scalp. Its symptoms include an inability to grow hair long and hair that is easily pulled out. We conducted a retrospective chart review of patients with LAS over the last 10 years at the Children's Hospital of Philadelphia and found 37 cases. LAS was more common in females and was found in all hair colors and skin types. Diagnosis of LAS should be made based on history, microscopic findings, and hair bulb and shaft features.

The CS Sulfation Motifs 4C3, 7D4, 3B3[-]; and Perlecan Identify Stem Cell Populations and Their Niches, Activated Progenitor Cells and Transitional Areas of Tissue Development in the Fetal Human Elbow.

We compared the immunohistochemical distribution of (1) the novel chondroitin sulfate (CS) sulfation motifs 7D4, 4C3, and 3B3[-], (2) native heparan sulfate (HS) and Δ-HS "stubs" generated by heparitinase III digestion and (3) the HS-proteoglycan (PG), perlecan, in the fetal human elbow joint. Putative stem cell populations associated with hair bulbs, humeral perichondrium, humeral and ulnar rudiment stromal/perivascular tissues expressed the CS motifs 4C3, 7D4, and 3B3[-] along with perlecan in close association but not colocalized. Chondrocytes in the presumptive articular cartilage of the fetal elbow expressed the 4C3 and 7D4 CS sulfation motifs consistent with earlier studies on the expression of these motifs in knee cartilage following joint cavitation. This study also indicated that hair bulbs, skin, perichondrium, and rudiment stroma were all perlecan-rich progenitor cell niches that contributed to the organization and development of the human fetal elbow joint and associated connective tissues. One of the difficulties in determining the precise role of stem cells in tissue development and repair processes is their short engraftment period and the lack of specific markers, which differentiate the activated stem cell lineages from the resident cells. The CS sulfation motifs 7D4, 4C3, and 3B3[-] decorate cell surface PGs on activated stem/progenitor cells and thus can be used to identify these cells in transitional areas of tissue development and in repair tissues and may be applicable to determining a more precise mode of action of stem cells in these processes. Isolation of perlecan from 12 to 14 week gestational age fetal knee rudiments demonstrated that perlecan in these fetal tissues was a HS-CS hybrid PG further supporting roles for CS in tissue development.

Trichoscopy of Focal Alopecia in Children - New Trichoscopic Findings: Hair Bulbs Arranged Radially along Hair-Bearing Margins in Aplasia Cutis Congenita

Purpose: To establish whether trichoscopy can be useful in the differential diagnosis of patchy alopecia in children. Procedures: The study was a retrospective analysis (2012-2015) and included 68 patients under 6 years of age. The inclusion criteria were age and the presence of 1-3 alopecia patches. A total of 124 alopecia patches were examined with the use of a videodermoscope: 102 alopecia areata, 8 tinea capitis, 6 trichotillomania, 3 temporal triangular alopecia and 5 aplasia cutis congenita. Results: In all aplasia cutis congenita lesions, trichoscopy revealed elongated hair bulbs visible through the semitranslucent epidermis, seen at the hair-bearing margin and radially arranged. Hair regrowth [upright regrowing hairs (44%), circular hairs (23%) and vellus hairs (20%)] was observed in the majority of alopecia areata patches. For triangular alopecia, upright regrowing hairs (100%; 3/3), vellus hairs (100%; 3/3) and circle hairs (33%; 1/3) were seen inside the alopecia patch. Conclusion: Trichoscopy is a useful technique for the differential diagnosis of patchy alopecia in children. A novel finding in this study indicates that radially arranged hair bulbs visible through the translucent epidermis are characteristic of nonbullous type aplasia cutis congenita.

Differential Expression between Human Dermal Papilla Cells from Balding and Non-Balding Scalps Reveals New Candidate Genes for Androgenetic Alopecia

Androgenetic alopecia (AGA) is a common heritable and androgen-dependent hair loss condition in men. Twelve genetic risk loci are known to date, but it is unclear which genes at these loci are relevant for AGA. Dermal papilla cells (DPCs) located in the hair bulb are the main site of androgen activity in the hair follicle. Widely used monolayer-cultured primary DPCs in hair-related studies often lack dermal papilla characteristics. In contrast, immortalized DPCs have high resemblance to intact dermal papilla. We derived immortalized human DPC lines from balding (BAB) and non-balding (BAN) scalp. Both BAB and BAN retained high proportions of dermal papilla signature gene and versican protein expression. We performed expression analysis of BAB and BAN and annotated AGA risk loci with differentially expressed genes. We found evidence for AR but not EDA2R as the candidate gene at the AGA risk locus on chromosome X. Further, our data suggest TWIST1 (twist family basic helix-loop-helix transcription factor 1) and SSPN (sarcospan) to be the functionally relevant AGA genes at the 7p21.1 and 12p12.1 risk loci, respectively. Down-regulated genes in BAB compared to BAN were highly enriched for vasculature-related genes, suggesting that deficiency of DPC from balding scalps in fostering vascularization around the hair follicle may contribute to the development of AGA.

Implementation and cost analysis of a regional farm animal cryobank: an Italian case study

Scientific and technical reports on farm animal genetic resources (AnGR) cryoconservation activities, and related costs, are needed to optimise conservation programmes. In this paper, we presented the recent Italian AnGR gene banking development, including the creation of the first regional animal cryobank, the ‘Lombardia Farm Animal Genetic Resources Cryobank’ (LABank). In order to provide indications on cryobanking costs, a detailed analysis of the expenses incurred during the creation of LABank was carried out. Currently, in LABank genetic material (spermatozoa, blood and hair bulbs) of Italian cattle, sheep and goat local breeds is cryopreserved, for a total amount of approximately 2500 semen doses collected from 46 donors of five local breeds. The costs incurred by creating the semen storage showed differences among species and semen collection procedures, providing indications to enhance the setting up of regional cryobanks.

Analysis of bovine viral diarrhoea virus in Korea dairy farms

A total of 2,194 bulk-tank milks from dairy farms were investigated, and of which 842 dairy farms (55,263 cattle) were assessed to detect persistently infected (PI) individual cattle by performing ELISA. Reverse transcription (RT)-PCR and immunohistochemistry (IHC) were used to develop a rapid screening test for detecting Bovine viral diarrhoea virus (BVDV) in ear tissues. Testing for the bulk-milk tank from dairy farms showed that 2,007 (91.5%) out of a total of 2,194 farms were determined to be positive for BVDV, while only 187 bulk-milk tanks (8.5%) were negative. A total of 55,263 cattle were tested for BVDV, of which 669 (1.2%) cattle from 387 farms (46%) were identified as PI. The distribution of PI was 178 (65.4%) of 272 herds under 14 months. A 220 (80.9%) herds were found in less than 23 month ages. Four infected herds were identified as PI based on RT-PCR analysis. BVDV protein was shown to be localized within epidermal hair bulb cells. This approach of targeted testing of dairy herds using ELISA and RT-PCR for pre-diagnostic testing proves to markedly reduce BVDV-infected herds in Korean dairy farms and in Korean Native Cows.

Influence of pesticide physicochemical properties on the association between plasma and hair concentration.

Although the relationship between chemical intake and resulting concentration in hair remains incompletely elucidated, the transfer from blood to hair bulb living cells is generally considered the main route of incorporation. The present work investigated the correlation between blood and hair concentration of 23 pesticides/metabolites from different chemical classes in rats submitted to chronic controlled exposure. Long-Evans rats were administered pesticides by gavage three times per week over a 90-day period. After hair sample decontamination, pulverization, and extraction, compounds were analyzed by gas chromatography tandem mass spectrometry (GC-MS/MS). Blood was collected at sacrifice, immediately turned into plasma, and analyzed after extraction for the same compounds by GC-MS/MS. The data obtained for all the investigated compounds demonstrated significant association between plasma and hair concentrations (P value of 2.97E-45 and R(Pearson) of 0.875), with the exception of three outliers. For all the target compounds, water solubility, lipophilicity, molecular weight, and charge were therefore investigated in order to understand the role of these parameters in outliers' specific behavior. Although a possible change in the charge through the transfer from blood to hair might be suspected for two outliers, on the whole the physicochemical parameters investigated here did not seem to influence incorporation of chemicals into hair. Our results support that the concentration of chemicals in hair mainly depends on the respective concentration in plasma and suggest that for most compounds, the transfer from blood to hair would not represent a limiting step in the incorporation.

Histological Evaluation of Equine Cadaver Skin Cores Dependent on Needle Type and Skin Preparation Method to Investigate Intramuscular Injection Complications in Horses

To histologically determine number and size of skin cores and hair fragments resulting from intramuscular injection techniques using equine cadaver skin explants. Clipped (clip) and nonclipped (no.clip) skin specimens, of the hamstring region (n = 10 horses), were obtained from freshly euthanized horses and punctured with 18G needles (18G), 18G needles with stylet (18GM), and 22G needles (22G). Needles were flushed with 0.2 mL of sterile saline solution. The saline was collected on slides and stained (Pappenheim). Skin cores, produced with 18G, were fixed with formalin solution (4%) and embedded in paraffin. Sections were stained with Masson's trichrome. Light microscopy was used for evaluation. Each different injection technique resulted in the identification of skin cores within a subset of slides obtained from the different 10 skin samples. Displaced skin cores were identified more frequently in clip samples than no.clip samples; 18G needle punctures resulted in the highest number and largest surface area of skin cores in both no.clip and clip samples as compared to 22G and 18GM punctures (P < .05); 18G needles with stylet punctures in no.clip samples resulted in the lowest number of skin cores. Histology of paraffin sections identified connective tissue (14/16 samples), stratum corneum (13/16), epidermis (12/16), isolated hair shafts and sweat glands (11/16), hair shafts integrated with epidermis and sebaceous glands (6/16), and hair bulbs (5/16). Skin cores can contain bacteria which may initiate infective injection complications. The coring incidence and hair fragmentation correlate with needle size; therefore, smaller needle sizes should be used.

Activation of the OVOL1-OVOL2 Axis in the Hair Bulb and in Pilomatricoma

OVOL1 and OVOL2, ubiquitously conserved genes encoding C2H2 zinc finger transcription factors in mammals, control epithelial cell proliferation, and differentiation, including those in skin. OVOL1 and OVOL2 expression is coordinately mediated via the Wnt signaling pathway, and OVOL1 negatively regulates OVOL2 expression in a transcriptional manner. Our previous study of OVOL1 expression in human skin revealed that OVOL1 is preferentially expressed in the inner root sheath of the hair follicle. Therefore, we hypothesized that the OVOL1-OVOL2 axis is involved in normal and neoplastic follicular differentiation. Immunohistochemical analysis showed that OVOL1 and OVOL2 were strongly expressed in a mutually exclusive manner in the cytoplasm of inner root sheath cells and matrix cells, respectively, in normal follicles. OVOL2 was also expressed in pilomatricoma, with only partial expression of OVOL1. Cultured human keratinocytes expressed OVOL1 and OVOL2 on both the mRNA and protein levels. The expression of OVOL2 was higher in keratinocytes transfected with siRNA of OVOL1. Ketoconazole, a hair growth stimulant, up-regulated the expression of OVOL1 but did not affect OVOL2 expression. These results indicated that the OVOL1-OVOL2 axis may actively contribute to cell differentiation and proliferation in the hair bulb, suggesting that the OVOL1 and OVOL2 may be therapeutic targets of hair disorders, including alopecia, and play important roles in the tumorigenesis of pilomatricoma.

Characterization and expression of soluble guanylate cyclase in skins and melanocytes of sheep

The study reported the characterization of soluble guanylate cyclase (sGC) with the size of CDS of 1860bp, encoding a protein of 620 amino acids and containing several conserved functional domains including HNOB, HNOBA, and CHD. Quantitative real time PCR analysis of sGC showed that the expression of sGC mRNA is higher (∼5 fold) in white sheep skin relative to black sheep skin with significant difference (P<0.01). Using a rabbit polyclonal anti-sGC antibody, an immune reactive band corresponding to sheep sGC protein was detected in the skin samples by Western blotting analysis, and the expression of sGC protein was significantly higher in white sheep skin compared to black sheep skin (P<0.01). Immunohistochemical analysis revealed that sGC protein was localized in cytoplasm and intercellular substance of upper hair papilla in hair follicles of white sheep skin, but the protein was localized in cytoplasm and intercellular substance of lower hair bulb and outer root sheath cells in hair follicles of black sheep skin. The immunocytochemical analysis revealed that sGC was expressed in melanocytes in vitro of sheep skin. Over expression of sGC in melanocytes resulted in decreased expression of key melanogenic genes including microphthalmia transcription factor (MITF), tyrosinase (TYR), tyrosinase related protein 1(TYRTP1), and tyrosinase related protein 2(TYRP2) both at mRNA and protein level. Moreover, the melanocytes was capable of producing cGMP and cAMP. The observed differential expression and localization of sGC in sheep skins and melanocytes and the capability of producing cGMP and cAMP, which suggested a potential role for this gene in hair color regulation.

Development of a Model for Chemotherapy-Induced Alopecia: Profiling of Histological Changes in Human Hair Follicles after Chemotherapy

Optimized research models are required to further understand the pathogenesis and prophylaxis of chemotherapy-induced alopecia. Our aim was to develop a mouse model for chemotherapy-induced alopecia by follicular unit transplantation of human hair follicles onto immunodeficient mice. Twenty-two weeks after transplantation, a single dose of cyclophosphamide (Cph) was administered to mice in the Cph100 (100 mg/kg) and Cph150 (150 mg/kg) groups. On day 6, hair follicles showed dystrophic changes, with swollen dermal papilla and ectopic melanin clumping in the hair bulb. In addition, upregulated expression of apoptotic regulators [P53, Fas/Fas-ligand, tumor necrosis factor-related apoptosis-inducing ligand/tumor necrosis factor-related apoptosis-inducing ligand receptor (TRAIL/TRAIL receptor), and Bax], increased apoptotic matrix keratinocytes, downregulated Ki67 expression, and decreased melanogenic protein in the hair bulb were noted in both groups. After 12 treatment days, hair follicles in Cph100 mice appeared to diminish dystrophic changes. In contrast, hair follicles of Cph150 mice prematurely entered a dystrophic catagen phase after 9 treatment days, and immunofluorescence staining for Ki67 and melanogenic protein expressions was barely visible. Two hair follicle damage response pathways were observed in this model, namely dystrophic anagen (Cph100) and catagen (Cph150) pathways. Our model might be useful for further understanding the impact of chemotherapy on human hair follicles.

Miliacin Associated with Polar Lipids: Effect on Growth Factors Excretion and Extracellular Matrix of the Dermal Papilla Hair Follicle Model Maintained in Survival Conditions

Background: The Dermal Papilla (DP) consists in specialized dermal fibroblasts located at the base of hair follicles and secreting extracellular matrix, especially collagen and glycosaminoglycans. DP cells are responsible for the production of hair fibers, by inducing anagen phase, and by maintaining the hair in this growth phase. Miliacin (contained in millet oil) is known for its healing properties and activity thereof on cellular proliferation. Miliacin has been associated with polar lipids, which are known to act as a vector, for increasing the bioavailability of the active compounds. Objectives: To explain the cellular hair bulb stimulation by miliacin associated with polar lipids (MPL), we used a model of hair follicle maintained in survival conditions. The modulation of collagen and glycosaminoglycans in the DP, the mitotic index for keratinocytes in the hair bulb and the growth factors excretion (IGF1 and KGF assays) were studied. Materials and Methods: Human hair scalp fragments were maintained in survival conditions for 7 days and treated by MPL diluted in the culture media. Results: A significant increase (14.1%) of IGF1 with an important (140%) and significant stimulation of mitotic index (Ki67 positive cells) was observed in the epithelial cells of hair bulb with MPL. A significant increase (20.8%) of collagen thickness was measured in the connective tissue sheath of the hair in contact with MPL. Conclusion: Miliacin associated with polar lipids acts on dermal papilla where it stimulates IGF1 growth factor production and renewal of keratinocytes in hair bulb. It also increases the thickness of extracellular matrix of the connective tissue sheaths.

Th1 Chemokine CXCL10 and Alopecia Areata: The Possible Target for the Treatment of Alopecia Areata

Alopecia areata (AA) is an organ-specific and cell-mediated autoimmune disease. Recent studies have suggested the most important effector cell of AA is NKG2D+CD8+T cells, and outer root sheath (ORS) cells highly express NKG2D ligands, such as MICA, in AA lesions. T lymphocytes densely surround lesional hair bulbs, which is histologically referred to as “swarm of bees”. Immunohistochemical and real-time RT-PCR studies reveal that hair follicles of acute-phase AA expressed a high level of Th1-associated chemokine CXCL10. In the skin lesions of acute-phase AA, CXCR3+CD4+ and CXCR3+CD8+ T cells infiltrated in the juxta-follicular area. In chronic-phase AA, CXCR3+CD8+ T cells dominated the infiltrate around hair bulbs, possibly contributing to the prolonged state of hair loss. Lymphocytes obtained from a lesional skin of acute-phase AA contained CXCR3+CD4+ and CXCR3+CD8+ T cells at higher percentages than those of PBMCs, suggesting preferential emigration from the blood. Furthermore, freshly isolated PBMCs from acute-phase AA patients had a strong velocity of chemotaxis toward CXCL10 with increased expression of F-actin. Antihistaminic drugs have been used in Japan, and these have possibility to downregulate chemotactic activity in AA. Olopatadine shows suppressive effects of chemotactic activity in the AA patients’ CD4+ and CD8+ T cells towards CXCL10 by reducing CXCR3 expression, F-actin polymerization, and Ca++ influx. In conclusion, the increased production of CXCL10 from hair follicles induces preferential infiltrates of Th1 and Tc1 cells in the acute phase of AA, and Tc1 infiltration remains prolonged in the chronic phase. Therefore, inhibitory treatment of chemotactic activity might be novel target for the treatment of AA.

Visualization of Hair Bulbs through the Scalp: A Trichoscopic Feature of Erosive Pustular Dermatitis of the Scalp.

Erosive pustular dermatitis of the scalp (EPDS) typically affects elderly people with scarring alopecia. Videodermoscopy (VD) of the scalp has never been assessed in the diagnosis of EPDS. To evaluate the trichoscopy features of EPDS, we carried out a retrospective analysis of VD images obtained in the scalp of ten patients who affected by EPDS and were compared with those obtained from a series of thirty patients who affected by other type of scarring alopecia. The most specific VD feature was thus represented by evident hair bulb in the scarring scalp, observed in all patients.

Localizations of γ-Actins in Skin, Hair, Vibrissa, Arrector Pili Muscle and Other Hair Appendages of Developing Rats.

Six isoforms of actins encoded by different genes have been identified in mammals including α-cardiac, α-skeletal, α-smooth muscle (α-SMA), β-cytoplasmic, γ-smooth muscle (γ-SMA), and γ-cytoplasmic actins (γ-CYA). In a previous study we showed the localization of α-SMA and other cytoskeletal proteins in the hairs and their appendages of developing rats (Morioka K., et al. (2011) Acta Histochem. Cytochem. 44, 141–153), and herein we determined the localization of γ type actins in the same tissues and organs by immunohistochemical staining. Our results indicate that the expression of γ-SMA and γ-CYA is suggested to be poor in actively proliferating tissues such as the basal layer of the epidermis and the hair matrix in the hair bulb, and as well as in highly keratinized tissues such as the hair cortex and hair cuticle. In contrast, the expression of γ-actins were high in the spinous layer, granular layer, hair shaft, and inner root sheath, during their active differentiations. In particular, the localization of γ-SMA was very similar to that of α-SMA. It was located not only in the arrector pili muscles and muscles in the dermis, but also in the dermal sheath and in a limited area of the outer root sheath in both the hair and vibrissal follicles. The γ-CYA was suggested to be co-localized with γ-SMA in the dermal sheath, outer root sheath, and arrector pili muscles. Sparsely distributed dermal cells expressed both types of γ-actin. The expression of γ-actins is suggested to undergo dynamic changes according to the proliferation and differentiation of the skin and hair-related cells.

A Study of Noncultured Extracted Hair Follicle Outer Root Sheath Cell Suspension for Transplantation in Vitiligo.

Context:Vitiligo surgeries have come a long way from tissue grafts to cultured and non cultured cell transplantation. Extracted hair follicle outer root sheath cell transplantation (EHF ORS) suspension is more enriched with melanocyte. In a hair bulb, there is one melanocyte for every five keratinocytes which is much higher than the epidermal melanin unit.Aims:To analyse the effectiveness of cultured EHF ORS and to perform objective evaluation based on clinical improvement & photographic evidence. To observe any untoward events or side effects.Settings and Design:The study was open and uncontrolled. All the patients were screened at preliminary visit. Reviews were done every two weeks. The endpoint selected was six months post procedure.Materials and Methods:Twenty five patients of stable Vitiligo were included in the study and follicular unit were harvested by Follicular Unit Extraction method. Outer root sheath cells were extracted by trypsinization. The solution was transplanted over dermabraded recipient site. Pressure dressing was given. Patients were followed up regularly.Statistical Analysis Used:Descriptive Statistics, Chi-Square.Results:Mean ± SD repigmentation was 80.15% ± 22.9% with excellent repigmentation (90-100%) in 60% of patients.Conclusions:This method is safe, effective, and simpler than the other methods involving cell culturing and requiring a laboratory set-up but selection of patients is crucial for the success of the outcome.

Structural and Functional Analysis of Intact Hair Follicles and Pilosebaceous Units by Volumetric Multispectral Optoacoustic Tomography

Visualizing anatomical and functional features of hair follicle development in their unperturbed environment is key in understanding complex mechanisms of hair pathophysiology and in discovery of novel therapies. Of particular interest is invivo visualization of the intact pilosebaceous unit, vascularization of the hair bulb, and evaluation of the hair cycle, particularly in humans. Furthermore, noninvasive visualization of the sebaceous glands could offer crucial insight into the pathophysiology of follicle-related diseases and dry or seborrheic skin, in particular by combining invivo imaging with other phenotyping, genotyping, and microbial analyses. The available imaging techniques are limited in their ability for deep tissue invivo imaging of hair follicles and lipid-rich sebaceous glands in their entirety without biopsy. We developed a noninvasive, painless, and risk-free volumetric multispectral optoacoustic tomography method for deep tissue three-dimensional visualization of whole hair follicles and surrounding structures with high spatial resolution below 80 μm. Herein we demonstrate on-the-fly assessment of key morphometric parameters of follicles and lipid content as well as functional oxygenation parameters of the associated capillary bed. The ease of handheld operation and versatility of the newly developed approach poise it as an indispensable tool for early diagnosis of disorders of the pilosebaceous unit and surrounding structures, and for monitoring the efficacy of cosmetic and therapeutic interventions.

Making use of capuchins’ behavioral propensities to obtain hair samples for DNA analyses

&#x0D; &#x0D; &#x0D; Genotyping wild and captive capuchins has become a priority and hair bulbs have high quality DNA. Here, we describe a method to non-invasively collect fresh-plucked strands of hair that exploits capuchins’ manual dexterity and propensity to grasp and extract food. The apparatus consists of a transparent tube baited with food. Its extraction requires the monkey to place its forearm in contact with double-sided tape applied on the inner surface of the tube entrance. The “tube” method, successfully implemented with captive (N=23) and wild (N=21) capuchins, allowed us to obtain hair bulbs from most indi- viduals and usable genomic DNA was extracted even from a single bulb.&#x0D; &#x0D; &#x0D;