Fatty acid supplements improve hair coat condition in rhesus macaques

As captive rhesus macaques often exhibit hair loss, alopecia was quantified and behavior was recorded before, during, and after fatty acid supplementation in six macaques. Fatty acid treatment was associated with a decrease in alopecia and in self‐grooming behavior. Therefore, fatty acids may be a viable treatment for alopecia in some captive primates.     

Exosomes derived from uMSCs promote hair regrowth in alopecia areata through accelerating human hair follicular keratinocyte proliferation and migration

Alopecia areata (AA) is a complex genetic disease that results in hair loss due to an autoimmune-mediated attack on the hair follicle. Mesenchymal stem cells (MSCs) have great potential to induce hair regeneration due to their strong secretion ability and multidirectional differentiation. Recent studies have revealed that the therapeutic potential of MSCs comes from their secretion ability, which can produce large amounts of bioactive substances and regulate the key physiological functions of subjects. The secretion products of MSCs, such as vesicles, exosomes, and conditioned media, have significant advantages in preparing of biological products derived from stem cells. Human umbilical cord mesenchymal stem cells (uMSCs) are the best choice for exosome production. uMSCs are obtained from the human umbilical cord. The umbilical cord is easy to obtain, and the efficiency of uMSCs isolation and culture higher than that of obtaining MSCs from bone marrow or adipose tissue. In this study, we investigated the effects of exosomes released from uMSCs in AA mice. In summary, due to easy isolation and cultivation, simple preparation, and convenient storage, it is possible to obtain uMSCs, or uMSCs exosomes for research and clinical treatment.     

Telogen elongation in the hair cycle of ob/ob mice

Alopecia impairs the physical and mental health of patients. We have previously shown that 8-week-old ob/ob mice have no reactivity to depilation, which is a stimulus that induces anagen transition in normal mice, while no hair cycle abnormalities have been reported in other studies until mice reach 7 weeks of age. Therefore, we hypothesized that ob/ob mice have abnormalities in hair cycle progression beyond 7 weeks of age. We examined 6- to 24-week-old ob/ob and 6- to 10-week-old normal mice. After acclimation, the dorsal skin was harvested and the hair cycle phase was identified histologically and immunohistochemically. Normal mice showed catagen–telogen and telogen–anagen transitions at 6 and 8–9 weeks old, respectively. In contrast, the anagen–catagen transition was observed in 7-week-old mice and the telogen phase was maintained from 10 to 24 weeks in most ob/ob mice. These results suggests that ob/ob mice are a possible model animal for telogen effluvium.     

脱发相关差异表达基因的生物信息学分析

利用生物信息学方法分析脱发相关差异表达基因,有望帮助了解脱发发生发展的分子机制。本研究从NCBI的子数据库GEO中选择基因表达谱GSE45512和GSE45513数据集,利用R语言limma工具包,筛选出两个物种斑秃样本与正常样本的共同显著差异表达基因。对这部分基因进行功能注释和蛋白互作网络分析,同时对全部差异表达基因进行基因集富集分析。结果发现,人头皮斑秃样本共筛选出225个差异表达基因;C3H/HeJ小鼠自发斑秃皮肤样本共筛选出337个差异表达基因;两个物种的共同显著差异表达基因有23个。GO功能富集分析和蛋白互作网络分析显示,这部分差异基因显著富集于免疫相关功能,并且彼此间存在蛋白互作关系。基因集富集分析显示两个物种的差异基因都能显著富集到趋化因子信号通路、细胞因子受体相互作用、金葡菌感染及抗原加工与呈递通路;而且人的下调差异基因不仅映射到了人类表型数据库的脱发表型,也映射到皮肤附属物病理相关表型。综上所述,本研究通过生物信息方法分析脱发皮肤组织与正常皮肤组织的差异表达基因,最终筛选出23个在人和小鼠中共同存在的显著差异表达基因;此外,分析发现脱发与免疫过程及皮肤附属物病变密切相关,这些结果为脱发的诊断和治疗提供了新思路。     

基于肠-皮肤轴的益生菌改善脱发机制研究进展

随着人们生活压力的提升,许多男性在中年时期出现脱发,严重者甚至会出现斑秃、全秃现象,其中以雄激素脱发最为常见。雄激素脱发的发生主要由于头皮中睾酮(testosterone,T)及其代谢产物二氢睾酮(dihydrotestosterone,DHT)含量较多,其主要机制为毛囊中5α-还原酶将游离的T转化为活性更高的DHT,导致雄激素水平过高。雄激素水平过高会引起毛囊微小化,使毛发生长周期变短而产生脱发。基于肠-皮肤轴的理论,越来越多的研究表明益生菌(probiotics)能够改善或治疗脱发症状。通过益生菌调节肠道菌群的平衡,可促进体内毛发生长因子的表达和毛囊细胞的生长,改善由于压力过大或雄激素水平过高等因素引起的脱发症状。本文主要探讨益生菌与毛发生长的相关性,通过其对神经系统、免疫系统和内分泌系统的调节作用,对益生菌改善脱发的功能和机理进行综述,以期为研发改善脱发的食品和药物提供理论依据。     

Activation of Notch1 in the hair follicle leads to cell-fate switch and Mohawk alopecia

The Notch signaling pathway has been shown to control cell-fate decisions during mouse development. To study the role of Notch1 in epidermal differentiation and the development of the various cell types within the mouse hair follicle, we generated transgenic mice that express a constitutive activated form of Notch1 under the control of the involucrin promoter. Transgenic animals express the transgene in the suprabasal epidermal keratinocytes and inner root sheath of the hair follicle, and develop both skin and hair abnormalities. Notch1 overexpression leads to an increase of the differentiated cell compartment in the epidermis, delays inner root sheath differentiation, and leads to hair shaft abnormalities and alopecia associated with the anagen phase of the hair cycle.     

Platelet sonicates activate hair follicle stem cells and mediate enhanced hair follicle regeneration

An increasing number of studies show that platelet‐rich plasma (PRP) is effective for androgenic alopecia (AGA). However, the underlying cellular and molecular mechanisms along with its effect on hair follicle stem cells are poorly understood. In this study, we designed to induce platelets in PRP to release factors by calcium chloride (PC) or by sonication where platelet lysates (PS) or the supernatants of platelet lysate (PSS) were used to evaluate their effect on the hair follicle activation and regeneration. We found that PSS and PS exhibited a superior effect in activating telogen hair follicles than PC. In addition, PSS injection into the skin activated quiescent hair follicles and induced K15⁺ hair follicle stem cell proliferation in K14‐H2B‐GFP mice. Moreover, PSS promoted skin‐derived precursor (SKP) survival in vitro and enhanced hair follicle formation in vivo. In consistence, protein array analysis of different PRP preparations revealed that PSS contained higher levels of 16 growth factors (out of 41 factors analysed) than PC, many of them have been known to promote hair follicle regeneration. Thus, our data indicate that sonicated PRP promotes hair follicle stem cell activation and de novo hair follicle regeneration.     

An analysis of gene expression data involving examination of signaling pathways activation reveals new insights into the mechanism of action of minoxidil topical foam in men with androgenetic alopecia

Androgenetic alopecia is the most common form of hair loss. Minoxidil has been approved for the treatment of hair loss, however its mechanism of action is still not fully clarified. In this study, we aimed to elucidate the effects of 5% minoxidil topical foam on gene expression and activation of signaling pathways in vertex and frontal scalp of men with androgenetic alopecia. We identified regional variations in gene expression and perturbed signaling pathways using in silico Pathway Activation Network Decomposition Analysis (iPANDA) before and after treatment with minoxidil. Vertex and frontal scalp of patients showed a generally similar response to minoxidil. Both scalp regions showed upregulation of genes that encode keratin associated proteins and downregulation of ILK, Akt, and MAPK signaling pathways after minoxidil treatment. Our results provide new insights into the mechanism of action of minoxidil topical foam in men with androgenetic alopecia.     

The cell biology of human hair follicle pigmentation

Although we have made significant progress in understanding the regulation of the UVR‐exposed epidermal‐melanin unit, we know relatively little about how human hair follicle pigmentation is regulated. Progress has been hampered by gaps in our knowledge of the hair growth cycle’s controls, to which hair pigmentation appears tightly coupled. However, pigment cell researchers may have overly focused on the follicular melanocytes of the nocturnal and UVR‐shy mouse as a proxy for human epidermal melanocytes. Here, I emphasize the epidermis‐follicular melanocyte pluralism of human skin, as research models for vitiligo, alopecia areata and melanoma, personal care/cosmetics innovation. Further motivation could be in finding answers to why hair follicle and epidermal pigmentary units remain broadly distinct? Why melanomas tend to originate from epidermal rather than follicular melanocytes? Why multiple follicular melanocyte sub‐populations exist? Why follicular melanocytes are more sensitive to aging influences? In this perspective, I attempt to raise the status of the human hair follicle melanocyte and highlight some species‐specific issues involved which the general reader of the pigmentation literature (with its substantial mouse‐based data) may not fully appreciate.     

Deletion of hypoxia-inducible factor prolyl 4-hydroxylase 2 in FoxD1-lineage mesenchymal cells leads to congenital truncal alopecia

Hypoxia-inducible factors (HIFs) induce numerous genes regulating oxygen homeostasis. As oxygen sensors of the cells, the HIF prolyl 4-hydroxylases (HIF-P4Hs) regulate the stability of HIFs in an oxygen-dependent manner. During hair follicle (HF) morphogenesis and cycling, the location of dermal papilla (DP) alternates between the dermis and hypodermis and results in varying oxygen levels for the DP cells. These cells are known to express hypoxia-inducible genes, but the role of the hypoxia response pathway in HF development and homeostasis has not been studied. Using conditional gene targeting and analysis of hair morphogenesis, we show here that lack of Hif-p4h-2 in Forkhead box D1 (FoxD1)-lineage mesodermal cells interferes with the normal HF development in mice. FoxD1-lineage cells were found to be mainly mesenchymal cells located in the dermis of truncal skin, including those cells composing the DP of HFs. We found that upon Hif-p4h-2 inactivation, HF development was disturbed during the first catagen leading to formation of epithelial-lined HF cysts filled by unorganized keratins, which eventually manifested as truncal alopecia. Furthermore, the depletion of Hif-p4h-2 led to HIF stabilization and dysregulation of multiple genes involved in keratin formation, HF differentiation, and HIF, transforming growth factor β (TGF-β), and Notch signaling. We hypothesize that the failure of HF cycling is likely to be mechanistically caused by disruption of the interplay of the HIF, TGF-β, and Notch pathways. In summary, we show here for the first time that HIF-P4H-2 function in FoxD1-lineage cells is essential for the normal development and homeostasis of HFs.     

A scoring system for coat and tail condition in ringtailed lemurs,Lemur catta

Coat condition can be influenced by a wide variety of disorders and thus provides a useful tool for noninvasive health and welfare assessments in wild and captive animals. Using Lemur catta as an exemplar, we offer a 6‐step scoring system for coat and tail condition, ranging from perfectly fluffy to half or more of body and tail being hairless. The categories are described in detail and illustrated with sample pictures from a wild population in Berenty Reserve, Madagascar. Furthermore, we elaborate on intermediate conditions and discoloration of fur. Coat condition scoring allows the comparison between years, seasons, and the effect of toxin, disease or stress. Although this system was developed for wild L. catta, we believe it can also be of value for other species. We recommend scoring coat condition in healthy wild mammal populations to give a baseline on yearly and seasonal variations vs. deteriorating health conditions or pathology. Am. J. Primatol. 71:183–190, 2009. © 2009 Wiley‐Liss, Inc.     

Coat condition, housing condition and measurement of faecal cortisol metabolites--a non-invasive study about alopecia in captive rhesus macaques (Macaca mulatta)

BACKGROUND: Previous studies have characterized alopecia in captive rhesus macaques (Macaca mulatta) by a mixed partial to complete alopecia in a bilateral symmetric pattern. METHODS: In this study, coat condition assessments were related to exogenous and endogenous factors in captive rhesus macaques under different housing conditions in order to identify disturbances in environmental factors controlling or influencing hair growth. Additionally, the degree of alopecia was investigated in relation to adrenal endocrine function as an indicator of social stress using faecal glucocorticoid measurements. RESULTS: Hair loss was found to vary with season and sex, was most pronounced in adult females during the winter and spring months. Generally, infants were not affected, but alopecia developed during adolescence. However, the housing system, available enclosure space and variations in group size and composition also appeared to influence coat condition. Levels of immunoreactive cortisol metabolites (11-oxoetiocholanolone) in faeces were significantly negatively correlated with alopecia, suggesting a relationship between hypothalamic-pituitary-adrenal (HPA) axis activity and hair loss in captive rhesus macaques. CONCLUSIONS: Although the present study demonstrates the influence of the HPA axis on coat condition, it is not known if hair loss is caused by abnormal behaviour or hormonal imbalances of the HPA axis itself. Our data suggest that alopecia in rhesus macaques is a highly complex multicausal disorder.     

Effect of equilibrium pH on the structure and properties of bleach-damaged human hair fibers

Hair proteins are significantly affected by environmental pH. This impact tends to increase with prior hair damage. To understand how pH affects bleached hair properties, we utilized a number of techniques allowing for the determination of hair thermal properties, swelling and water sorption, and dry and wet tensile properties. At pH 5, hair proteins had the best structural integrity, as determined by differential scanning calorimetry and the highest tensile modulus. At pH 10, protein cross-linking density decreased, water content and hair cross-sectional diameter increased. Alkaline treatment, when compared with pH 5, did not reduce intermediate filament conditions (evaluated via enthalpy measurement) nor mechanical property performance in the wet state. In contrast to alkaline-treated hair, bleached hair equilibrated at pH 3 behaved very differently: it contained two different crosslink density zones, was the least stiff in dry and stiffest in wet conditions. Additionally, it absorbed less water and had the lowest diameter because of reduced water binding by protonated carboxyl groups. The pH 3 to 10 did not affect the mechanical strength of bleached hair in dry or wet conditions.     

Relative and combined effects of ethanol and protein deficiency on some hair trace elements

This study was performed in order to analyze the relative and combined effects of ethanol and protein deficiency on hair copper, zinc, manganese, and iron content in four groups of seven animals each which were pair-fed during 8 wk with (1) a nutritionally adequate diet, (2) a 36% (as energy) ethanol-containing isocaloric diet, (3) a 2% protein, isocaloric diet, and (4) a 36% ethanol, 2% protein isocaloric diet, respectively, following the Lieber-DeCarli model, and to analyze the relationship between hair copper, zinc, manganese, and iron content, and the liver and muscle content of these elements. Although there was a trend to higher levels of all the elements analyzed in the the hair of the low-protein fed animals, differences were statistically significant regarding copper and manganese, effects being solely attributable to the low protein diet, not to ethanol. Moreover, hair copper was significantly, inversely related with final weight and weight loss. There were significant relationship between liver zinc and muscle zinc (r=0.57, p=0.002), but not between liver or muscle zinc and hair zinc; no correlations were observed between muscle copper and hair copper, nor between liver manganese and hair manganese. An inverse, statistically significant correlation was observed between liver copper and hair copper (r=−0.39, p<0.05).