Morphometric Analysis of the Human Scalp Hair Follicle: Practical Implications for the Hair Transplant Surgeon and Hair Regeneration Studies

Incorporation of suvorexant and lemborexant into hair and their distributions after a single intake

PURPOSE

This study examined the applicability of hair analysis as an approach to identify suvorexant (SUV) and lemborexant (LEM) intake by analyzing black hair specimens collected from study participants after a single oral administration.

METHODS

Hair specimens were collected form participants who took a single dose of 10 mg SUV or 5 mg LEM. Identification of the dual orexin receptor antagonists (DORAs) and their metabolites was performed by liquid chromatography-tandem mass spectrometry. Reference standards of S-M9 and L-M4, the metabolites of SUV and LEM, respectively, were synthesized in our laboratory. Sectional analysis of 1-mm segments of the single-hair strands was also performed to investigate the incorporation behavior of the drugs into hair.

RESULTS

Unchanged SUV and LEM, and their metabolites S-M9 and L-M4 were detected even in the single-hair specimens. Results of the segmental hair analysis showed predominant incorporation of the drugs into hair through the hair bulb region rather than through the upper dermis zone of the hair root. The drug concentrations in the hair specimens, collected about 1 month after intake, were 0.033-0.037 pg/hair strand (0.17-0.19 pg/mg) for SUV and 0.054-0.28 pg/hair strand (0.28-1.5 pg/mg) for LEM. The calculated distribution ratios of the DORAs into hair to the oral doses were much lower than those of benzodiazepines and zolpidem reported in a previous study.

CONCLUSIONS

This is the first report of the detection of the DORAs in hair. The incorporation behavior of the DORAs into hair revealed herein are crucial for proper interpretation of hair test results.

Use of fractionated laser therapy for the treatment of androgenetic alopecia: a systematic review and meta-analysis

Procedural management, including fractionated laser therapy, has been increasingly investigated for the management of androgenetic alopecia (AGA). However, no comprehensive resources exist detailing the efficacy of fractionated laser therapies used for the treatment of AGA. A systematic review investigating fractionated laser use for AGA was performed, separated into each distinct fractionated laser modality. A meta-analysis was performed to examine improvement in hair counts and hair shaft diameter. Fourteen studies were included for systematic review, which identified the use of erbium-glass, thulium, erbium-ytrrium:aluminum garnet (YAG), and carbon dioxide (CO2) fractionated laser for the treatment of AGA. In the meta-analysis, fractionated laser combination therapy showed significant improvement in hair shaft diameter (2.51, 95% CI 2.37-2.65, I2 = 90.54). Fractionated laser monotherapy alone significantly improved hair shaft diameter (2.28 95% CI 2.03-2.52, I2 = 91.20%). This effect was durable on subgroup analysis for both erbium-glass (2.36 95% CI 2.01-2.71, I2 = 92.05%) and thulium (1.61 95% CI 1.08-2.15, I2 = < 0.00%). There was no improvement in hair shaft count for any laser modality. Erbium-glass laser is an effective modality as either monotherapy or combination with topical/injectable therapies to improve hair shaft diameter in AGA.

Observation on cadavers and through ultrasonography using a 2 mm needle length for intradermal injections

BACKGROUND

An intradermal injection is a medical procedure that involves administering a small amount of medication or substance into the dermal layer of the skin. This research focused on identifying the most suitable injection needle for precise intradermal administration of skin boosters.

METHODS

The study involved conducting intradermal injections on four cadavers and participants using a 2 mm length, 34-gauge needle (N-Finders, Inc., South Korea). During the cadaveric study, the polynucleotide prefilled syringe was dyed green, and an anatomist performed dissections, removing only the skin layer. Ultrasonographic observations were carried out to ensure accurate intradermal injection placement.

RESULTS

In all four cadavers, the facial injections at the anterior cheek region were precisely administered intradermally at a 30-degree injection angle. However, the 90-degree injection was found just below the dermal layer upon skin layer removal.

DISCUSSION

The findings suggest that using a 2 mm needle length allows for easy and convenient intradermal injections.

Atmospheric pressure plasma treatment of skin: penetration into hair follicles

Sterilization of skin prior to surgery is challenged by the reservoir of bacteria that resides in hair follicles. Atmospheric pressure plasma jets (APPJs) have been proposed as a method to treat and deactivate these bacteria as atmospheric plasmas are able to penetrate into structures and crevices with dimensions similar to those found in hair follicles. In this paper, we discuss results from a computational investigation of an APPJ sustained in helium flowing into ambient air, and incident onto a layered dielectric similar to human skin in which there are idealized hair follicles. We found that, depending on the location of the follicle, the bulk ionization wave (IW) incident onto the skin, or the surface IW on the skin, are able to launch IWs into the follicle. The uniformity of treatment of the follicle depends on the location of the first entry of the plasma into the follicle on the top of the skin. Typically, only one side of the follicle is treated on for a given plasma pulse, with uniform treatment resulting from rastering the plasma jet across the follicle over many pulses. Plasma treatment of the follicle is sensitive to the angle of the follicle with respect to the skin, width of the follicle pocket, conductivity of the dermis and thickness of the underlying subcutaneous fat layer, the latter due to the change in capacitance of the tissue.

Micro-segmental hair analysis: detailed procedures and applications in forensic toxicology

PURPOSE

Since the 1980s, the detection sensitivity of mass spectrometers has increased by improving the analysis of drugs in hair. Accordingly, the number of hair strands required for the analysis has decreased. The length of the hair segment used in the analysis has also shortened. In 2016, micro-segmental hair analysis (MSA), which cuts a single hair strand at a 0.4-mm interval corresponding to a hair growth length of approximately one day, was developed. The advantage of MSA is that the analytical results provide powerful evidence of drug use in the investigation of drug-related crimes and detailed information about the mechanism of drug uptake into hair. This review article focuses on the MSA technique and its applications in forensic toxicology.

METHODS

Multiple databases, such as SciFinder, PubMed, and Google, were utilized to collect relevant reports referring to MSA and drug analysis in hair. The experiences of our research group on the MSA were also included in this review.

RESULTS

The analytical results provide a detailed drug distribution profile in a hair strand, which is useful for examining the mechanism of drug uptake into hair in detail. Additionally, the analytical method has been used for various scenarios in forensic toxicology, such as the estimation of days of drug consumption and death.

CONCLUSIONS

The detailed procedures are summarized so that beginners can use the analytical method in their laboratories. Moreover, some application examples are presented, and the limitations of the current analytical method and future perspectives are described.

Quantified Facial Rejuvenation Utilizing High Intense Focus Ultrasound with Multiple Penetrative Depths

Background

Multiple penetration depths of high-intensity focused ultrasound (HIFU) treatment for facial rejuvenation have not been quantified.

Methods

We enrolled 12 participants (n=24) to undergo one session of HIFU rejuvenation between January 1, 2019, and January 10, 2020. We used a 2-, 4.5-, and 6-mm focal depth transducer on the upper and middle face. We evaluated efficacy on days 60 and 90 by using our specific assessment system.

Results

The average eyebrow peak and pupil-eyebrow peak angles significantly increased by 2° (p < 0.0005) and decreased by 1° (p < 0.0001), respectively, at day 90. The shortened eyebrow-iris length indicated that the forehead tissues had lifted and moved medially to the central face. Supraorbital tissues were also vertically elevated, marked by the eyebrow-orbital (p = 0.0016) and vertical palpebral fissure lengths (p = 0.0052), which both exhibited a 0.8-cm elevation. For the midface, the increased canthus-oral-nasal angle (p = 0.5881) and decreased tragus-oral length (p = 0.5881) indicated that laxity had been corrected through lifted oral commissure, though the data were not statistically significant. No serious side effects were observed.

Conclusion

HIFU treatment with multiple depths quantitatively improved both upper-facial rejuvenation and midface rejuvenation after a single session.

Longitudinal isotope ratio variations in human hair and nails

Due to the straightforward and non-invasive sampling, ease of transport and long-term storage and access to time-resolved information, determination of element concentrations and isotope ratios in hair and nails finds increasing use. Multi-isotopic information preserved in keratinous tissues allows one to reveal dietary, physiological and environmental influences, but progress in this area is still limited by complicated and time-consuming analytical procedures and challenges in accuracy assessment. In this study, longitudinal distributions of δ³⁴S, ⁸⁷Sr/⁸⁶Sr, ^207,208Pb/²⁰⁶Pb, δ⁶⁶Zn, δ⁵⁶Fe, δ⁶⁵Cu, δ²⁶Mg, and δ¹¹⁴Cd were obtained for hair and nails collected from nine subjects with different age, biological sex, diet and/or place of residence. For S and Zn, the distribution along hair strands revealed a trend towards a heavier isotopic signature from the proximal to the distal end, with a maximum difference within the hair of a single subject of 1.2‰ (Δ³⁴S) and 0.4‰ (Δ⁶⁶Zn). For Fe, Cu, Mg and Cd, a shift towards either a lighter (Cu) or heavier (Fe, Mg and Cd) isotopic composition is accompanied by increasing concentration towards the distal hair end, indicating possible isotope fractionation during deposition or external contamination with a different isotopic composition. Pb and Sr isotope ratios are relatively stable throughout the hair strands despite notable concentration increases towards the distal end, likely reflecting external contamination. The isotopic composition of Sr points to tap water as a probable main source, explaining the relative stability of the ratio for individuals from the same geographical location. For Pb, isotopic compositions suggest tap water and/or indoor dust as possible sources. Similar δ³⁴S, ⁸⁷Sr/⁸⁶Sr, ^207,208Pb/²⁰⁶Pb, δ⁶⁶Zn, δ⁵⁶Fe, and δ⁶⁵Cu observed for hair, fingernails and toenails sampled from the same individual suggest that keratinous tissues are conservative receivers of internal and external inputs and can be used complementary. Seasonal variation in δ³⁴S, ^207,208Pb/²⁰⁶Pb, and δ⁶⁵Cu was observed for fingernails.

Microneedling and Its Use in Hair Loss Disorders: A Systematic Review

Introduction

Microneedling (MN) is a minimally invasive procedure involving the induction of percutaneous wounds with medical-grade needles. In this literature review, we investigate clinical data on MN for the treatment of hair loss disorders.

Methods

A literature search was conducted through PubMed up to November 2021 to identify original articles evaluating the use of MN on hair loss disorders. The database was searched using the following keywords: “microneedling,” “micro needling,” “micro needle,” “microneedle,” “needle,” “dermaroller” and “alopecia,” “hair loss,” “alopecia,” “areata,” “cicatricial,” or “effluvium.”

Results

A total of 22 clinical studies featuring 1127 subjects met our criteria for inclusion. Jadad scores ranged from 1 to 3, with a mean of 2. As an adjunct therapy, MN improved hair parameters across genders and a range of hair loss types, severities, needling devices, needling depths of 0.50–2.50 mm, and session frequencies from once weekly to monthly. Across 17 investigations totaling 911 androgenic alopecia (AGA) subjects, MN improved hair parameters when paired with 5% minoxidil, growth factor solutions, and/or platelet-rich plasma (PRP) topicals, or when introduced to subjects whose hair count changes had plateaued for ≥ 6 months on other treatments. Across four investigations on 201 alopecia areata (AA) subjects, MN improved hair parameters as a standalone therapy versus cryotherapy, as an adjunct to 5-aminolevulinic acid and photodynamic therapy, and equivalently when paired with topical PRP versus carbon dioxide laser therapy with topical PRP. Across 657 subjects receiving MN, no serious adverse events were reported.

Conclusions

Clinical studies demonstrate generally favorable results for MN as an adjunct therapy for AGA and AA. However, data are of relatively low quality. Significant heterogeneity exists across interventions, comparators, and MN procedures. Large-scale randomized controlled trials are recommended to discern the effects of MN as a standalone and adjunct therapy, determine best practices, and establish long-term safety.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-021-00653-2.

Melanogenesis markers expression in premature graying of hair- a cross-sectional study

BACKGROUND

Studies on mice and aging human hair follicles provide compelling evidence that graying of hair results from premature differentiation of Melanocyte stem cells (MeSC) in the niche/bulge.

OBJECTIVE

  To analyze whether differentiation of melanocyte stem cells is responsible for premature graying of hair (PGH).

METHODS

  Twenty- five patients of PGH (n=25) attending dermatology department were recruited. Five unpigmented and five pigmented hairs were obtained per patient by separating individual follicles by 1 mm punch biopsies. The hairs were dissected at a distance of 2 mm from the bulb to separate the stem cells (upper segment) (US) from the melanocytes (lower segment) (LS). RNA was extracted from hair follicle segments US and LS, and expression of GP100, Tyrosinase (TYR) and Tyrosinase related protein-1 (TYRP1) genes was quantified using Qiagen one-step RT-PCR kit.

RESULTS

  We found melanogenesis gene expression in both temporary (US) and permanent (LS) segments of unpigmented and pigmented hair follicles. When compared between the US and LS of white hair, the expression of TYR and GP100 was much higher in US than LS, suggestive of melanogenesis in the bulge. Similarly, when compared between white and black US, the expression of all three genes was higher in white US than black US, although not statistically significant.

LIMITATIONS

Low samples size and lack of data pertaining to the expression of genes at protein level are the limitations of current study.

CONCLUSION

Even though this pilot study data yielded key information about the expression of GP100, TYR and TYRP-1 at mRNA level, further studies quantifying the expression of these genes at protein level are needed to provide additional clues to further address the results in detail.

Effect of De-epithelialization on Graft Survival Rate After Follicular Unit Extraction

BACKGROUND

To achieve a natural postoperative appearance, hair grafts are often de-epithelialized from the epidermis during follicular unit extraction (FUE). However, the effect of de-epithelialization on the survival rate of transplanted hair follicles (HFs) has not been investigated.

OBJECTIVE

To investigate the effect of de-epithelialization on the survival rate of transplanted HFs.

METHODS

A total of 64 male patients with androgenetic alopecia were included in this study. They were randomly divided into de-epithelialization and control groups. Organ culture was performed to assess the elongation of hair shaft and the percentage of anagen HFs in both groups. Patients were followed up postoperatively to evaluate complications, postoperative shedding, survival rates, and satisfaction.

RESULTS

No significant difference in hair shaft elongation and percentage of anagen HFs was observed between both groups. The immediate postoperative satisfaction in the control group was much lower than that in the de-epithelialization group (71.25% and 100%, respectively). No significant differences in shedding rate, graft survival rate, and complications were noticed between both groups.

CONCLUSION

Follicular de-epithelialization does not affect the survival rate of graft in FUE. Based on these data, de-epithelialization may improve immediate postoperative appearance and lead to a more pleasing cosmetic outcome.

Hair Transplantation: Basic Overview

Modern hair restoration surgery is based on a technique known as follicular unit transplantation in which follicular units (FUs) are the exclusive structures used as hair grafts. In Part 1 of this two-part review, we describe how the techniques employed in hair transplantation have evolved into their present forms. Anatomic concepts of specific relevance for dermatologists are discussed, including the distribution and ex-vivo morphology of scalp FUs. Male androgenetic alopecia and female pattern hair loss are the most common reasons for hair loss consultations with dermatologists and will be the primary focus of this review. However, as not all hair disorders are suitable for transplantation, this review will also describe which scalp conditions are amenable to surgery and which are not. In addition, guidelines are provided to help dermatologists better define good or bad candidates for hair transplantation. Finally, other conditions for which hair transplantation surgery is indicated are reviewed.

Establishment of an Efficient Primary Culture System for Human Hair Follicle Stem Cells Using the Rho-Associated Protein Kinase Inhibitor Y-27632

Background

Hair follicle tissue engineering is a promising strategy for treating hair loss. Human hair follicle stem cells (hHFSCs), which play a key role in the hair cycle, have potential applications in regenerative medicine. However, previous studies did not achieve efficient hHFSC expansion in vitro using feeder cells. Therefore, there is a need to develop an efficient primary culture system for the expansion and maintenance of hHFSCs.

Methods

The hHFSCs were obtained by two-step proteolytic digestion combined with microscopy. The cell culture dishes were coated with human fibronectin and inoculated with hHFSCs. The hHFSCs were harvested using a differential enrichment procedure. The effect of Rho-associated protein kinase (ROCK) inhibitor Y-27632, supplemented in keratinocyte serum-free medium (K-SFM), on adhesion, proliferation, and stemness of hHFSCs and the underlying molecular mechanisms were evaluated.

Results

The hHFSCs cultured in K-SFM, supplemented with Y-27632, exhibited enhanced adhesion and proliferation. Additionally, Y-27632 treatment maintained the stemness of hHFSCs and promoted the ability of hHFSCs to regenerate hair follicles in vivo. However, Y-27632-induced proliferation and stemness in hHFSCs were conditional and reversible. Furthermore, Y-27632 maintained propagation and stemness of hHFSCs through the ERK/MAPK pathway.

Conclusion

An efficient short-term culture system for primary hHFSCs was successfully established using human fibronectin and the ROCK inhibitor Y-27632, which promoted the proliferation, maintained the stemness of hHFSCs and promoted the ability to regenerate hair follicles in vivo. The xenofree culturing method used in this study provided a large number of high-quality seed cells, which have applications in hair follicle tissue engineering and stem cell therapy.

Single hair analysis: Validation of a screening method for over 150 analytes and application on documented single-dose cases

Hair is the matrix of choice in forensic toxicology when retrospective analysis is needed. Nonetheless, due to misalignment, different growth stages and segmentation lengths of 0.5-1 cm, resolution of time is limited. By segmental analysis of single hairs, most of these factors can be compensated and resolution of time is enhanced. A method for manually segmenting single hairs in 2-mm sections and screening for 156 analytes by liquid chromatography coupled to tandem mass spectrometry has been developed and validated. The method was applied to 15 single-dose cases concerning different pharmaceuticals by analyzing 10 hairs each, sampled 1 and 2 months after ingestion in most cases. The validation showed a lower limit of quantification of ≤1.25 pg/segment for ~90% of analytes and good accuracy. Many substances could be detected in the presented cases, whereas detection of benzodiazepines and low dosed opioids remains challenging. In positive cases, characteristic peak-shaped concentration profiles across the hairs were obtained. The segment with most coinciding peak maxima can be allocated to the time of ingestion. A method for the determination of individual hair growth rate was applied and revealed a gap between expected and actual position of peak maxima. Additionally, different localization of simultaneously administered substances was observed. These findings were tried to be explained by different routes of incorporation and may contribute to current knowledge. The presented method may directly be applied to similar questions in hair analysis, and the findings are considered important for interpreting further results in single hair analysis.

A Literature Review of the Microneedle Therapy System for Hair Loss

This literature review was designed to investigate the effects of the microneedle therapy system (MTS) on alopecia in experimental, and clinical studies. The MTS is acupuncture needling therapy delivered by a roller. A literature review of studies published before May 2020 was conducted using 9 online databases, and a total of 13 studies (4 in vivo studies and 9 clinical trials) were included. Most studies showed that the MTS was effective when used in combination with other treatments. In vivo studies reported an increased level of hair growth factors following treatment. Typically, 1.5 mm needles were used in the MTS treatment and photographic evaluation (by either camera or microscope) was reported in most studies. Oriental medicine research included 2 in vivo studies, which reported positive effects when combined with the MTS. There were no reported severe side effects. the MTS might be safe and has a drug delivery effect. Further studies need to be conducted regarding the frequency and needle length depending on the type of alopecia using Oriental and Western medicine.

Dosimetric study of whole-brain irradiation with high-energy photon beams for dose reduction to the scalp

OBJECTIVE

To evaluate the efficiency of high-energy photons for mitigating alopecia due to whole-brain irradiation (WBRT).

METHODS

Planning CT data from 10 patients who received WBRT were collected. We prepared 4 WBRT plans that used 6 or 15 MV photon beams, with or without use of a field-in-field (FiF) technique, and compared outcomes using a treatment planning system. The primary outcome was dose parameters to the scalp, including the mean dose, maximum dose, and dose received to 50% scalp(D50%). Secondary outcomes were minimum dose to the brain surface.

RESULTS

Using FiF, the mean doses were 24.4-26.0 and 22.4-24.1 Gy, and the maximum doses were 30.5-32.1 and 28.5-30.8 Gy for 6 and 15 MV photon beams, respectively. Without FiF, the mean doses were 24.6-26.9 and 22.6-24.5 Gy, and the maximum doses were 30.8-34.6 and 28.6-32.4 Gy for 6 and 15 MV photon beams. The 15 MV plan resulted in a lower scalp dose for each dose parameter (p < 0.001). Using FiF, the minimum doses to the brain surface for the 6 and 15 MV plans were 28.9 ± 0.440 and 29.0 ± 0.557 Gy, respectively (p = 0.70). Without FiF, the minimum doses to the brain surface for the 6 and 15 MV plans were 28.9 ± 0.456 and 29.0 ± 0.529, respectively (p = 0.66).

CONCLUSION

Compared with the 6 MV plan, the 15 MV plan achieved a lower scalp dose without impairing the brain surface dose.

ADVANCES IN KNOWLEDGE

High-energy photon WBRT may mitigate alopecia of patients who receiving WBRT.

Microneedling in androgenetic alopecia; comparing two different depths of microneedles

BACKGROUND

Microneedling has shown to have positive therapeutic effects in treatment of androgenetic alopecia (AGA); however, the best microneedling protocol is still controversial.

AIMS

Investigating effect of microneedling with 2 different depths of penetration on promoting hair growth in patients with AGA.

METHODS

Sixty patients, in the age of 18-45 years old with moderate and severe AGA, were allocated into 3 groups of control: treatment with minoxidil 5% lotion; group A: treatment with minoxidil 5% lotion and biweekly microneedling with a depth of 1.2 mm and group B: treatment with minoxidil 5% lotion and biweekly microneedling with a depth of 0.6 mm during 12 weeks. Efficacy parameters including change of hair count and hair thickness from baseline and assessment of hair growth by patient and investigator were evaluated.

RESULTS

Compared with the baseline, a significant increase in hair count and hair thickness was observed in all three groups after completion of the treatment course (P < .05). The mean rise in hair count (P = .017) and hair thickness (P = .007) was significantly greater in group B compared with control group. Investigator's evaluation of hair regrowth was significantly greater in group A (P = .04) and group B (P = .007) compared with control group.

CONCLUSION

Microneedling with a depth of 0.6 mm in combination with minoxidil is more effective than minoxidil monotherapy in patients with AGA in terms of hair count and hair thickness. This depth of penetration tended to be more beneficial than depth of 1.2 mm.

Revisiting Perioperative Hair Removal Practices

The standard of practice for perioperative hair removal is largely based on research that is outdated and underpowered. Although there is evidence to support the practice of clipping instead of shaving, current recommendations are to remove hair only when absolutely necessary. Human hair is bacteria-laden and challenging to disinfect, and clipping can be a safe method of hair removal that does not damage the skin. This article considers the removal of hair at the incision site with clippers, either before the patient enters the OR or in a manner that completely contains clipped hair, for every procedure, not just when absolutely necessary. There have been only two studies to date comparing clipping with no hair removal; more research is needed on this subject.

Mohs Surgery for Advanced Tumors of the Scalp

BACKGROUND

The scalp presents unique surgical challenges, and specialized techniques are sometimes required to achieve optimal results. Tumors arising on the scalp may also be at increased risk of complications such as in-transit metastasis and perineural invasion.

OBJECTIVE

To review challenges to Mohs micrographic surgery on the scalp and techniques for successful tumor extirpation and reconstruction.

METHODS AND MATERIALS

This article reviews our experience with tumors of the scalp including techniques that we have found helpful both for tumor removal and for reconstruction.

CONCLUSION

Familiarity with the anatomy of the scalp as well as common challenges encountered during Mohs surgery may help improve outcomes and impart increase confidence to the practicing surgeon.

Modelling the risk of radiation induced alopecia in brain tumor patients treated with scanned proton beams

PURPOSE

To develop normal tissue complication probability (NTCP) models for radiation-induced alopecia (RIA) in brain tumor patients treated with proton therapy (PT).

METHODS AND MATERIALS

We analyzed 116 brain tumor adult patients undergoing scanning beam PT (median dose 54 GyRBE; range 36-72) for CTCAE v.4 grade 2 (G2) acute (≤90 days), late (>90 days) and permanent (>12 months) RIA. The relative dose-surface histogram (DSH) of the scalp was extracted and used for Lyman-Kutcher-Burman (LKB) modelling. Moreover, DSH metrics (Sx: the surface receiving ≥ X Gy, D_2%: near maximum dose, D_mean: mean dose) and non-dosimetric variables were included in a multivariable logistic regression NTCP model. Model performances were evaluated by the cross-validated area under the receiver operator curve (ROC-AUC).

RESULTS

Acute, late and permanent G2-RIA was observed in 52%, 35% and 19% of the patients, respectively. The LKB models showed a weak dose-surface effect (0.09 ≤ n ≤ 0.19) with relative steepness 0.29 ≤ m ≤ 0.56, and increasing tolerance dose values when moving from acute and late (22 and 24 GyRBE) to permanent RIA (44 GyRBE). Multivariable modelling selected S_21Gy for acute and S_25Gy, for late G2-RIA as the most predictive DSH factors. Younger age was selected as risk factor for acute G2-RIA while surgery as risk factor for late G2-RIA. D_2% was the only variable selected for permanent G2-RIA. Both LKB and logistic models exhibited high predictive performances (ROC-AUCs range 0.86-0.90).

CONCLUSION

We derived NTCP models to predict G2-RIA after PT, providing a comprehensive modelling framework for acute, late and permanent occurrences that, once externally validated, could be exploited for individualized scalp sparing treatment planning strategies in brain tumor patients.

Histopathology of aging of the hair follicle

Hair follicles experience several changes with aging, the most noticeable of which is graying of the hair shaft due to loss of melanin. Additional changes in the diameter and length of the hair have contributed to the concept of senescent alopecia, which is different from androgenetic alopecia according to most. Graying happens in most individuals, although in different grades and starting at different ages. It is related to a decrease in the number and activity of the melanocytes of the hair bulb, which eventually completely disappear from the bulb of the white hair. Residual non-active melanocytes remain in the outer root sheath and in the bulge, which allows for repigmentation of the hair under certain stimuli or conditions.

Mission impossible: Dermal delivery of growth factors via microneedling

The clinical application of transdermal delivery has been limited to lipophilic drugs with a molecular weight of less than 500 Da. The development of polymeric microneedles enabled the transdermal delivery of larger proteins and drugs. Extensive research has been conducted on the molecular size, solubility, pH, concentration, and polarity of transdermal delivery; however, the maximal molecular weight for transdermal microneedle delivery has not been established. Clinicians often use simple microneedles to deliver high molecular weight growth factors of platelet-rich plasma across the skin; thus, we set out to explore the feasibility of delivering growth factors through microneedling. In this communication, we present histological evidence that microneedling do not enhance transdermal delivery of growth factors and thus provide no clinical benefit.

Targeted heat activation of HSP promoters in the skin of mammalian animals and humans

The use of highly inducible HSP promoters for exerting spatial and/or temporal control over the expression of therapeutic transgenes has long been discussed. Localized and time-limited induction of the heat shock response may potentially also be of medical interest. However, such applications would require targeted delivery of heat doses capable of activating HSP promoters in tissues or organs of interest. Accessible areas, including the skin and tissues immediately underneath it, may be most readily targeted. A few applications for heat-directed or heat-controlled therapy in the skin might involve expression of proteins to restore or protect normal skin function, protein antigens for vaccination/immunotherapy, vaccine viruses or even systemically active proteins, e.g., cytokines and chemokines. A review of the literature relating to localized heat activation of HSP promoters and HSP genes in the skin revealed that a multitude of different technologies has been explored in small animal models. In contrast, we uncovered few publications that examine HSP promoter activation in human skin. None of these publications has a therapeutic focus. We present herein two, clinically relevant, developments of heating technologies that effectively activate HSP promoters in targeted regions of human skin. The first development advances a system that is capable of reliably activating HSP promoters in human scalp, in particular in hair follicles. The second development outlines a simple, robust, and inexpensive methodology for locally activating HSP promoters in small, defined skin areas.

Scalp as a donor site in children: Is it really the best option?

BACKGROUND

Since 2003 we have used the scalp as a donor site for split skin grafts (SSGs) in major burns when there was a shortage of conventional donor areas. However, we seen a high incidence of complications, contrary to international experience.

OBJECTIVE

The aim of this study was to analyze the results and complications related to the scalp as a donor site and to determine whether there is an association between our specific patient population and the complications encountered.

METHODS

A retrospective review of our scalp donor site outcomes over a 12-year period was conducted. The cohort included 25 patients, 15 of black African descent, nine of mixed race and one Caucasian. The various hair types were identified based on ethnicity and classified into eight types. Most of our patients had hair types VI-VIII. None of these patients had scalp burns and all received standard burn treatment. The SSGs were taken with an electric dermatome with a standard micrometric setting of 0.2mm. Complications were categorized into short- or long-term, with a mean follow-up time of 1.59years.

RESULTS

The mean age of the 25 children was 5.7years. Nineteen sustained flame burns and 6 sustained hot water burns, with a mean total body surface area of 44.9%. A total of 43 scalp procurements were performed in the 25 patients studied. The group of 15 black African patients (hair types VI-VIII) had a total of 22 procurements, the nine patients of mixed race (hair types III-V) had 18 procurements and the single Caucasian patient (hair types II-III) had two procurements. The median healing time was 15days, 11.8days and 8.5days, respectively, per group. Significant complications were encountered, including folliculitis 44%, non-healing wounds 52%, alopecia 16% and visible, hypopigmented scars 3%. One patient had a hypertrophic scar and no hair transfers to the recipient areas were observed. The various hair types correlated with the complications encountered. Five children, with an average burn size of 65.2% (range: 40-85%) died of sepsis. Due to the small sample size, the only statistically significant findings were related to the total body surface area of the burn and the number of times skin was harvested from the scalp, with a p-value of 0.005. The p-values for the healing times related to the first, second and third croppings, were p=0.022, p=0.00032 and p<0.001 respectively.

CONCLUSION

Our study suggests that in pediatric patients of black African descent (hair types VI-VIII) the scalp is not an ideal donor area, due to the unacceptably high incidence of complications. Hence, every precaution should be taken when it becomes necessary to harvest donor skin from the scalp.

Alopecia and platelet-derived therapies

Background

Platelet rich plasma (PRP) injections have emerged as a promising regenerative therapy for androgenetic alopecia (AGA). To date, injections of both autologous native and activated PRP have been administered to hair loss patients, and positive results have been observed. However, little to no work has yet to be seen wherein PRP treatments are combined with hair restoration surgeries. Furthermore, the PRP activation protocol in the hair restoration setting employs compounds with potentially deleterious side effects, namely thrombin or calcium gluconate. Therefore, the objectives of this work are to evaluate the effectiveness of platelet and platelet-derived products as augmented graft therapies in hair restoration surgeries and to compare the follicular regeneration rate of follicles transplanted in the presence of platelet lysate (PL) versus activated PRP (AA-PRP).

Methods

PL was administered to the frontal scalp of three male AGA patients. Three treatment zones measuring 4 cm^-2 were mapped in the midline scalp region of each patient and equal number of follicular grafts were placed in each box along with PL, AA-PRP, or normal saline. The transplanted follicular grafts of a fourth patient were placed solely with PL. Hair checks in which the surface area of hair coverage was quantified were performed at follow-up appointments ranging from 3.5 to 7 months post-surgery. In these appointments, the number of follicular units with hairs measuring 50 mm or more were counted to determine the percentage of graft hair regeneration. Growth factor (GF) concentrations [vascular endothelial growth factor (VEGF), transforming growth factor beta 1 (TGF-β1), PDGF-BB, IGF-1] in PL and AA-PRP were also measured for an independent subject set.

Results

Follicular regeneration in transplanted grafts was found to be superior for those placed with PL rather than AA-PRP or saline at all follow-up dates. Specifically, at 3.5 months post-op, 89%±9%, 74%±7%, and 57%±10% of follicular units had regenerated hair in the PL, AA-PRP, and saline treatment zones, respectively. At 4 months post-op, 99%, 75%, and 71% of follicle regeneration had occurred in the PL, AA-PRP, and saline treatment areas, respectively. Impressively, when PL was injected alone, the patient experienced a 50% increase in follicular unit density and a 122% increase in hair density 7 months post-injection. When GF concentrations were measured, PL generated from a 30-min sonication of PRP was found to have significantly higher levels of VEGF, PDGF-BB, and TGF-β1 than AA-PRP.

Conclusions

PRP remains a promising hair loss therapy and should be evaluated further for use not only as an independent therapeutic tool, but also as a treatment to augment surgical procedures. PL in particular affords an effective and efficacious therapeutic product given that the lysate may be obtained by mechanical rather than chemical means. Ultrasonic waves provide sufficient energy to rupture platelet cell walls, and centrifugation may be used to separate the lysate from cell fragments prior to delivery.

The scalp as a donor site for skin grafting in burns: retrospective study on complications

Background

Split skin grafting (SSG) is the cornerstone in the treatment of deep burns and large skin defects. Frequently used donor sites are the thigh, abdomen and buttocks. The scalp is less common while considered as a reliable donor site. Advantages are a large surface area, rapid wound healing, cosmetically favourable results and multiple harvests from the same donor site. Complications include scab formation, chronic folliculitis and alopecia but have been recorded sporadically in previous studies. This article evaluates the complication rate of the scalp donor site in the treatment of deep burns in the Beverwijk Burn Centre.

Methods

A retrospective study was performed of all patients who received a skin graft from the scalp at the Beverwijk Burn Centre between January 2004 and December 2012. Data were collected from medical files of included patients, including gender, age, type of burn (scald, flame, other) and total body surface area (TBSA) burned at the time of first surgery. Postoperative variables were healing time of the donor site and incidence of complications. During follow-up, the incidence of late complications was reviewed.

Results

A total number of 105 grafts were analysed in 93 patients: 58 males (62 %) and 35 females (38 %), with a median age of 2 years and 3 months old. Of the patients, 30 (32 %) had flame burns and 57 (61 %) had scald burns. Eighty-seven percent of patients had a TBSA burned of 5 % or less. All donor sites healed within 14 days. No alopecia or scar hypertrophy developed at the donor sites. Two patients (2.2 %) developed folliculitis; one patient (1.1 %) showed scab formation.

Conclusions

The scalp as a donor site in our Burn Centre shows a comparable short-term complication rate to the previous literature, with quick healing and no long-term complications. Therefore, we propose the consideration of the scalp as a primary donor site, especially in young children, where the scalp offers a larger donor site area than the buttocks or thighs.

Expression of pluripotency markers in Arbas Cashmere goat hair follicle stem cells

In our previous work, we found that the Inner Mongolia Arbas Cashmere goat hair follicle stem cells (gHFSCs) can be successfully differentiated into adipocyte, chondrocyte, and osteocyte lineages. In this study, we further examined the expression of the pluripotency and stemness markers Oct4, Nanog, Sox2, AKP, and TERT in gHFSCs by immunocytochemistry, flow cytometry, real-time PCR, and Western blot. Immunofluorescent staining showed that the gHFSCs were positive for all five markers. Fluorescence-activated cell sorting (FACS) further analyzed the positive expression of Oct4, Nanog, and Sox2 in the gHFSCs. Compared with Arbas Cashmere goat adipose-derived stem cells (gADSCs) at the mRNA expression level, Oct4 was relatively highly expressed in gHFSCs, 41.36 times of the gADSCs, and Nanog was 5.61, AKP was 2.74, and TERT was 2.10 times, respectively (p < 0.01). Western blot indicated that all markers are expressed at the protein level in the gHFSCs. When compared with gADSCs, using α-tubulin as a reference protein, gray intensity analysis showed that the expression of Oct4, Nanog, AKP, and TERT were, respectively, 5.94, 10.78, 1.33, and 1.39 times of gADSCs. Additionally, mRNA and protein expression of Sox2 were detected in the gHFSCs but not in the gADSCs. The protein expression pattern of these markers was consistent with the mRNA results.

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 in vivo 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 in vivo imaging with other phenotyping, genotyping, and microbial analyses. The available imaging techniques are limited in their ability for deep tissue in vivo 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.

Human epithelial hair follicle stem cells and their progeny: current state of knowledge, the widening gap in translational research and future challenges

Epithelial hair follicle stem cells (eHFSCs) are required to generate, maintain and renew the continuously cycling hair follicle (HF), supply cells that produce the keratinized hair shaft and aid in the reepithelialization of injured skin. Therefore, their study is biologically and clinically important, from alopecia to carcinogenesis and regenerative medicine. However, human eHFSCs remain ill defined compared to their murine counterparts, and it is unclear which murine eHFSC markers really apply to the human HF. We address this by reviewing current concepts on human eHFSC biology, their immediate progeny and their molecular markers, focusing on Keratin 15 and 19, CD200, CD34, PHLDA1, and EpCAM/Ber-EP4. After delineating how human eHFSCs may be selectively targeted experimentally, we close by defining as yet unmet key challenges in human eHFSC research. The ultimate goal is to transfer emerging concepts from murine epithelial stem cell biology to human HF physiology and pathology.

Comparison of scalp and abdomen as split-thickness skin graft donor sites for aural stenosis repair

To evaluate and compare the scalp and the abdomen as split-thickness skin graft donor sites for aural stenosis repair. A total of 34 patients with aural stenosis were included in the study. All the patients underwent meatoplasty using split-thickness skin grafts. Among them, the skin graft donor site was the scalp in 11 patients and the abdomen in the other 23 patients. The surgical team followed the patients in the outpatient department for at least 6 months after surgery. Evaluations concerned healing of the donor site, hair regeneration of the donor site, survival of split-thickness skin grafts, reoccurrence of aural stenosis and hair growth in the ear canal. The incidences of reoccurrence of aural stenosis in the two groups were compared. Subjective scar evaluation of the donor sites was performed using the Patient Scar Assessment Scale (PASA). The scale items were pain, itching, color, stiffness, thickness and irregularity. All the scalp and abdominal donor sites healed well with no sign of infection. Hair regrowth and reepithelialization was observed at all the scalp donor sites. Pink discoloration was observed at the scalp donor sites in six patients 2-3 months after surgery and disappeared 6-9 months after surgery. Scars were observed at the scalp donor sites in two patients 6 months after surgery. No alopecia was observed at the scalp donor sites. The scars and pink discoloration were hidden in the hair. Scars and/or discoloration were observed at all the abdominal donor sites 12 months after surgery. All the scalp and abdominal skin grafts survived with no sign of infection. Hair growth was observed in the ear canals in two patients in the scalp group. The incidences of reoccurrence of aural stenosis were 0 % (0/23) in the abdominal group and 9.1 % (1/11) in the scalp group, respectively (Chi square test, p > 0.05). The PASA values about color, stiffness, thickness and irregularity were higher in the abdominal group than in the scalp group (Mann-Whitney U test, p < 0.001). The PASA values about pain and itching were the same (Mann-Whitney U test, p > 0.05). The scalp meets most requirements of an ideal donor site of skin grafts for aural stenosis. The advantages of scalp as a donor site include easy accessibility in the operative field, simple postoperative care, low risk of infection, rapid wound healing, minimal interference with rehabilitation, and minimal scar formation.

Hair restoration surgery: the state of the art

Hair restoration is a highly sophisticated subspecialty that offers significant relief to patients with hair loss. An improved understanding of the aesthetics of hair loss and cosmetic hair restoration, hair anatomy and physiology, and the development of microvascular surgical instrumentation has revolutionized the approach to surgical hair restoration since the original description. Additional elements that contribute to the current state of the art in hair restoration include graft size, site creation, packing density, and medical control of hair loss. The results of hair restoration are natural in appearance and are provided with a very high level of patient satisfaction and safety. This aspect of cosmetic surgery is a very welcome addition to a traditional aesthetic practice and serves as a tremendous source for internal cross-referral. The future of hair restoration surgery is centered on minimal-incision surgery as well as cell-based therapies.

Scalp as split thickness skin graft donor site for congenital atresia repair

OBJECTIVE

Describe the use of the scalp as a donor site for split thickness skin grafts in otologic surgery.

MATERIALS AND METHODS

Review of the literature with detailed description of surgical technique and authors' experience.

RESULTS

One hundred and forty- four scalp split thickness skin grafts were obtained between 2007 and 2011. No significant complications were observed with optimal cosmetic results.

CONCLUSIONS

The scalp is a viable option as a split thickness skin graft donor site for otologic and other head and neck surgery. Advantages include improved cosmetic results at the donor site, quick healing with low complication rates, and easy accessibility in the operative field.

Improving optical contact for functional near‑infrared brain spectroscopy and imaging with brush optodes

A novel brush optode was designed and demonstrated to overcome poor optical contact with the scalp that can occur during functional near infrared spectroscopy (fNIRS) and imaging due to light obstruction by hair. The brush optodes were implemented as an attachment to existing commercial flat-faced (conventional) fiber bundle optodes. The goal was that the brush optodes would thread through hair and improve optical contact on subjects with dense hair. Simulations and experiments were performed to assess the magnitude of these improvements. FNIRS measurements on 17 subjects with varying hair colors (blonde, brown, and black) and hair densities (0-2.96 hairs/mm(2)) were performed during a finger tapping protocol for both flat and brush optodes. In addition to reaching a study success rate of almost 100% when using the brush optode extensions, the measurement setup times were reduced by a factor of three. Furthermore, the brush optodes enabled improvements in the activation signal-to-noise ratio (SNR) by up to a factor of ten as well as significant (p < 0.05) increases in the detected area of activation (dAoA). The measured improvements in SNR were matched by Monte Carlo (MC) simulations of photon propagation through scalp and hair. In addition, an analytical model was derived to mathematically estimate the observed light power losses due to different hair colors and hair densities. Interestingly, the derived analytical formula produced excellent estimates of the experimental data and MC simulation results despite several simplifying assumptions. The analytical model enables researchers to readily estimate the light power losses due to obstruction by hair for both flat-faced fiber bundles and individual fibers for a given subject.