What’s new in hair — February 2017 | Dr. Claire A. Higgins
Hair follicle changes following intense pulsed light axillary hair reduction: histometrical, histological and immunohistochemical evaluation
Arch Dermatol Res. 2017 Feb 22. doi: 10.1007/s00403-017-1714-7. [Epub ahead of print]
Laser hair removal is commonly used to treat unwanted hair, however there are alternatives such as Intense Pulsed Light (IPL) therapy which may also prove cosmetically beneficial. IPL is characterised by pulses of 400-1200nm light. It is thought that melanin in the hair fiber absorbs this light in the 625-825nm wavelength range, producing energy which destroys the follicle. In this study, El-Domyati et al evaluate the morphological changes that occur in follicles after IPL therapy. The axillary hair on the right axille of 21 healthy female volunteers was treated 6 times with IPL over a 12 week period, while the left axille was shaved as a control. They found significant decreases in hair fiber count 1 month after cessation of treatment, while regrown hair had significantly smaller diameters that those regrown after shaving. Authors found a significant decrease in follicular number, and in addition, of the follicles which were present, significantly more were in telogen compared to anagen. Alluding to mechanism, they also found decreases in cell proliferation after treatment, and increases in p53 which activates apoptosis. These observations suggest that the thermal injury elicited as a result of IPL results in cell death within the follicle. IPL is a cheap alternative to laser hair removal, and as the authors show here, it is also an effective alternative.
Dermatol Surg. 2017 Feb 17. doi: 10.1097/DSS.0000000000001049. [Epub ahead of print]
Platelet Rich Plasma (PRP) is fast becoming a popular, and alternative treatment for hair loss. Despite this, there is still a lack of clinical evidence supporting claims it works for Androgenetic Alopecia. In this study, Anitua et al took 29 patients (13 male, 16 female) with patterned hair loss, and treated them with five intradermal injections of Platelet Rich Growth Factor (PRGF), a specific type of autologous PRP, over a 12 month period. Efficacy of PRGF was assessed by phototrichogram, and digital image analysis was used to calculate hair density, diameter and the terminal to vellus ratio. The results showed that hair density and diameter both significantly increased with PRGF treatment, while the terminal to vellus ratio remained the same. Of the 29 patients assessed, only one indicated they were unsatisfied with the treatment, however, care must be taken evaluating patient responses since many will be happier as a result of them being treated by a clinician in the first place. While the figures in this manuscript showing the cosmetic benefit of PRGF are impressive, to make critical evaluations and test the true efficacy of PRGF a placebo should also be assessed. Specifically, a placebo introduced by an intradermal injection should be used, since the mode of delivery itself may result in increased blood flow and subsequently hair growth.
Expression profiling and bioinformatic analyses suggest new target genes and pathways for human hair follicle related microRNAs
BMC Dermatol. 2017 Feb 22;17(1):3. doi: 10.1186/s12895-017-0054-9.
MicroRNAs (miRNAs) are small non-coding RNAs which can influence gene expression by targeting messenger RNAs (mRNAs). Previous studies have characterised the miRNA profile of mouse skin with hair follicles in different cycle stages; anagen, catagen and telogen. In this study, Hochfeld et al collected hair follicles from the frontal and occipital scalp of 25 male donors, and performed both whole transcriptome analysis of mRNA, and profiling of 10 candidate miRNAs. Of the 10 miRNAs assessed, miR-205 was found at the highest levels in human follicles. This miRNA was selected as a candidate miRNA as it is essential for hair follicle stem cell proliferation in murine skin morphogenesis. Despite this miRNA having the highest expression in human follicles, the authors did not correlate its’ expression with any mRNAs. Instead, they focused on miR-31, miR-24 and miR-106a, as the miRNA target prediction algorithms demonstrated that these three targeted the highest number of mRNAs which were also present in human follicles. Work to elucidate the differential expression of both mRNAs and miRNAs in hair from different body sites would be an interesting line of research going forward.
Induction of hair follicle dermal papilla cell properties in human induced pluripotent stem cell-derived multipotent LNGFR(+)THY-1(+) mesenchymal cells
Sci Rep. 2017 Feb 21;7:42777. doi: 10.1038/srep42777.
The dermal papilla (DP) is a small mesenchymal population of cells located at the base of the hair follicle. They are difficult to isolate, and when they are isolated and grown in culture they do not maintain intrinsic DP characteristics. In this manuscript, Veraitch et al assessed whether they could establish DP cells, by directing the differentiation of induced pluripotent stem cells (iPSCs), which would circumvent the requirement to isolate and culture DP from hair follicles. First, they differentiated iPSCs down a mesenchymal lineage, specifically into induced mesenchymal cells (iMCs), which they demonstrated had multipotent potential and could differentiate into osteoblasts, chondrocytes and adipocytes. Next, they exposed iMCs to retinoic acid (RA) and DPAC, which is a DP culture activating medium previously characterised by the group , to attempt to turn iMCs into induced DP cells (iDPSCs). While some DP specific genes were already present in iMCs, the authors found that the RA+DPAC induced additional DP specific genes, while iMC genes concomitantly decreased. In addition, the iMCs changed shape, and started to resemble DP cells. Using a co-culture system they also found that iDPSCs could induce expression of ‘hair related genes’ in keratinocytes, indicating communication and signalling between the mesenchymal and epithelial cells types. Lastly, the cells were also able to respond to minoxidil, in a similar manner to normal DP cells. These iDPSC could therefore be a useful, and unlimited source of cells to identify new therapeutics which target the DP to reverse hair loss, and can be generated without the requirement of obtaining a hair biopsy for DP isolation.
1. Ohyama, M., et al., Restoration of the intrinsic properties of human dermal papilla in vitro. J Cell Sci, 2012. 125(Pt 17): p. 4114-25.
Dermatol Ther (Heidelb). 2017 Feb 20. doi: 10.1007/s13555-017-0171-8. [Epub ahead of print]
Female pattern hair loss (FPHL) is the most common hair loss condition in women, characterised by hair follicle miniaturisation and a shortened anagen. Often women complain of excessive shedding, but when they present at the clinic this is difficult to diagnose. Patients often do not have positive results with the hair pull test, however, this just demonstrates that their hairs are not loose, and it does not inform the clinician about shedding rates. While other hair shedding tests are available, they are either invasive, time consuming, or difficult to conduct in a single consultation. In this paper, Martínez-Velasco et al have developed a visual tool which they propose can be used in an office setting to aid in the assessment of hair shedding. Using this visual tool which has been designed relative to hair length, patents self-evaluate their shedding. Individuals were stratified into groups containing those with short, medium, or long hair, and asked to self-evaluate using the visual tool specific for their hair length. The first self-evaluation was conducted with 60 individuals with no hair loss, and these self-reported a shedding score ranging from 1-4, with an average of 2.35. In comparison, 94 patients who had been diagnosed with FPHL self-evaluated with a score ranging from 5-9, and an average of 7. To verify if patient’s perceptions correlated with the actual number of hairs shed, the authors counted hairs from 14 samples taken from 2 women over a 2 week period. They found that there was a positive correlation (p=0.88) with the amount of hair shed and the self-reported score. In conclusion, patients themselves are the most effective at detecting hair shedding, and they can often detect shedding prior to clinical diagnosis. However, this visual tool may be useful to help clinicians quickly distinguish ‘normal’ shedding which is expected, from excessive shedding in conditions such as FPHL. It is also important to note that the visual tool developed in this study is suitable for use in Caucasian women with thick hair, and alternative scores will need to be developed for different ethnicities.
Int J Dermatol. 2017 Feb 23. doi: 10.1111/ijd.13572. [Epub ahead of print]
Alopecia areata (AA) is an autoimmune disease, which results in hair loss. With current treatment regimes, patients can always be stratified into responders and non-responders, and there not a treatment which suits everyone. As such, there is still a need for alternative treatment plans. In this paper, Herz-Ruelas et al assessed whether UVA-1 treatment, a form of phototherapy which penetrates well into the skin dermis, would be suitable as an alternative treatment for AA. Twenty two patients with AA, with hair loss ranging from <25% hair loss, through 75-99% were treated initially with 30mJ/cm2 UVA-1 3-5 times per week. Response was evaluated after 25 sessions, and if patients were not responding their dose was escalated to 60mJ/cm2 and eventually 120mJ/cm2. When patients were assessed collectively as a group at the end of the study, it was found that there was a significant increase in the number of anagen follicles, and a decrease in catagen follicles. However, like other treatments there was again stratification of patients, with responders and non-responders. At the end of the study, only the patients who had less than 25% hair loss to start with showed total regrowth, while the patients with 75-99% hair loss remained unchanged. Thus, this indicates that UVA-1 treatment can effectively treat AA, but it is only useful for patients with <25% hair loss to start with.