Congenital hypotrichosis in a French bulldog

The occurrence of congenital alopecia in one of a litter of four female French bulldogs is described. With the exception of the hair coat the affected bitch was clinically normal. The distribution of the sparse hair (head, tip of the tail and paws) mimicked that seen in the Chinese crested dog. Histopathological examination of skin biopsies revealed features frequently observed in congenital alopecia - a reduction in number of hair follicles, hypoplasia or absence of epidermal appendages and pronounced follicular hyperkeratosis, abnormalities of collagen and elastic fibres were not detected.     

Alopecia in the horse – an overview

Dr Stannard explains different forms of alopecia in the horse with emphasis on the hair follicle and its function in the production of hairs. Both normal and abnormal patterns of hair growth and shedding in the horse are reviewed. Overviews of several specific hair follicle abnormalities, both inflammatory and noninflammatory, are discussed in detail with their clinical relevance. Some of the clinical entities covered in this section (linear alopecia and alopecia areata) are caused by immunological attack against normal structures and could have been placed in Immunologic diseases. However, because the clinical presentation for these entities is alopecia, Dr Stannard chose to include them in his notes on alopecia. Other inclusions in this section include cutaneous bacterial infections (e.g. pastern folliculitis and dermatophilosis) as well as fungal infections of the hair (dermatophytosis).     

毛囊形态发生和周期性变化相关信号因子在绒山羊中的研究进展

毛发的生长与毛囊的形态发生和周期性变化密不可分,毛囊的形态发生和周期性变化依赖上皮角质细胞和真皮间质细胞的相互作用。作者综述了毛囊的结构、形态发生、周期性变化,讨论了毛囊形态发生和周期性变化过程中相关信号因子的作用,以期为在分子水平阐述毛囊形态发生和周期性变化的调控机制提供依据,为提高绒毛的产量和品质提供参考。     

哺乳动物毛囊发育及调控研究进展

毛囊具有高度自我更新能力,是哺乳动物特有的皮肤构造,且是唯一呈终生周期性生长的器官。毛囊的发生始于胚胎期,皮肤上皮层细胞和下胚层细胞间的一系列相互作用诱导形成毛囊,之后毛囊进入周期性循环,包括生长、退行和休止3个阶段。毛囊的发育过程中受到复杂的网络调控。近年来,关于哺乳动物毛囊发育及调控机制的研究取得了较大进展。已有研究表明,毛囊的发生及循环过程中受到多种因子的调控,不同信号通路及miRNA和lncRNA相关基因的参与,构成了一个庞大而又复杂的网络调控图谱,每种调控因子间的相互促进及制约为毛囊的发生及循环提供了必要的保障。文章简述了人、羊及小鼠等哺乳动物毛囊形态发生、周期性循环及相关调控因子的研究进展,为更加全面地了解哺乳动物毛囊发育过程及调控机制提供了参考,同时对人工控制毛绒的周期生长进而提高毛绒产量和质量提供了思路。     

Congenital alopecia in a Bichon Frise

A Bichon Frise pup had congenital alopecia. Histologic evaluation revealed the absence of hair follicles, arector pili muscles, sebaceous glands, and sweat glands. Unlike previously described cases of congenital ectodermal defect, this alopecia was not associated with any color pattern; the pup was white until it was 4 months old, at which time normal black and brown pigmentation developed independently of the alopecic pattern.     

毛囊形态发生和分子调控及其在绒山羊上的研究进展

毛囊是皮肤重要的附属器官,它是由上皮细胞和真皮细胞间相互作用发育而形成的,有很多信号分子控制着这一过程。毛囊相关性状对于绒毛的产量和质量有重要影响。本文从人和小鼠的研究现状着手,详细阐述了毛囊形态发生的规律以及它们的分子调控机理,并与绒山羊毛囊的变化作了比较,同时对近年来绒山羊毛囊分子调控方面的研究进行了综述,以期为今后有关绒山羊毛囊生长发育的研究提供参考依据。     

Anti‐isthmus autoimmunity in a novel feline acquired alopecia resembling pseudopelade of humans*

Pseudopelade is a primary scarring (cicatricial) alopecia of humans characterized by lymphocyte‐rich inflammation centred around the hair follicle isthmus. Lymphocyte folliculotropism is associated with isthmus apoptosis and, ultimately, follicular destruction and dermal fibrosis. In a cat, an acquired alopecia was diagnosed as pseudopelade based on the following criteria: (i) an adult‐onset, patchy to diffuse nonpruritic hair loss; (ii) an early folliculo‐destructive phase in which lymphocytes and dendritic cells accumulated in and around the follicular isthmus; and (iii) a late stage in which the lower segments of hair follicles underwent atrophy and were replaced by fibrosing tracts. Additionally, immunological investigations characterized the cytotoxic phenotype of isthmotropic lymphocytes and demonstrated the presence of circulating IgG autoantibodies specific for multiple follicular antigens. Altogether, the results of the present study suggest an immune‐mediated pathogenesis for this case of feline pseudopelade, similarly to that causing alopecia areata in humans and other mammalian species.     

Alopecia and dermatopathy of the lower back following pelvic fractures in three cats

Abstract   An alopecia and dermatopathy following pelvic fractures associated with vehicular trauma is reported in three cats. The animals presented 3–4 weeks post injury with acute hair loss, glistening appearance of the skin and erosions involving the lower back. Histological examination revealed atrophy of the hair follicles and adnexal structures and follicular telogenization, dermal fibroplasia and mild lymphocytic infiltrate, fibroplasia and inflammation in the panniculus. Vascular damage secondary to the external trauma to blood vessels supplying the skin over the lumbar region and subsequent ischaemia may represent the pathomechanism of this type of alopecia. Focal permanent hair loss can be expected.     

Characteristics of Ovarian Follicle Development in Domestic Animals

In most domestic animals the later stages of follicle development occurs in a wave‐like pattern during oestrous cycles (cattle, sheep, goats, horses and buffalo) or periods of reproductive activity (llamas and camels). A follicle wave is the organized development of a cohort of gonadotrophin‐dependent follicles all of which initially increase in size, but most of which subsequently regress and die by atresia (subordinate follicles). The number of remaining (dominant) follicles is specific to the species and is indicative of litter size. Follicle waves develop during both luteal and follicular phases and it is the dominant follicle(s) of the last follicular wave that ovulates. However, there are cases where dominant follicles from the last two follicle waves can ovulate (sheep and goats). There are exceptions to the organized wave‐like pattern of follicle growth where follicle development is apparently continuous (pigs and chickens). In these animals many follicles develop to intermediate diameters and at specific times follicles that are destined to ovulate are selected from this pool and continue growing to ovulation. Understanding the pattern of follicle development in different species is increasingly important for designing improved methods to manipulate reproduction in domestic animals.     

In vitro Follicle Growth: Achievements in Mammalian Species

The exact mechanisms regulating in vivo folliculogenesis in mammalians have only been partly unravelled. Some processes, such as the initiation of growth of primordial follicles are still poorly understood. This increases the difficulty to culture follicles in vitro as the primordial follicles will be the ultimate starting material for culture.
There are important species differences in regulation and timing of maturation, which makes it difficult to transpose techniques.
Only in the mouse model, live pups were born when primordial or early preantral follicles were cultured entirely in vitro . Although no systems are as yet permitting complete in vitro culture of early follicle stages in large animals or humans, parts of folliculogenesis have been successfully reproduced in vitro . This review summarizes achievements of the last years in follicle culturing starting off at several stages of development.
Future applications of in vitro follicle culture include fertility preservation for humans, preservation of rare animal species and creation of oocyte banks for research.     

The canine hair cycle - a guide for the assessment of morphological and immunohistochemical criteria

The hair follicle has a lifelong capacity to cycle through recurrent phases of controlled growth (anagen), regression (catagen) and quiescence (telogen), each associated with specific morphological changes. A comprehensive classification scheme is available for mice to distinguish the cycle stages anagen I-VI, catagen I-VIII and telogen. For dogs, such a classification system does not exist, although alopecia associated with hair cycle arrest is common. We applied analogous morphological criteria and various staining techniques to subdivide the canine hair cycle stages to the same extent as has been done in mice. Of all the staining techniques applied, haematoxylin and eosin stain, Sacpic, Masson Fontana and immunohistochemistry for vimentin and laminin proved to be most useful. To evaluate the applicability of our criteria, we investigated skin biopsies from healthy beagle dogs (n=20; biopsies from shoulder and thigh) kept in controlled conditions. From each biopsy, at least 50 hair follicles were assessed. Statistical analysis revealed that 30% of the follicles were in anagen (12% early and 18% late), 8% in catagen (2% early, 5% late and 1% not determinable) and 27% in telogen. Thirty-five per cent of hair follicles could not be assigned to a specific cycle stage because not all follicles within one biopsy were oriented perfectly. In conclusion, this guide will not only be helpful for the investigation of alopecic disorders and possibly their pathogenesis, but may also serve as a basis for research projects in which the comparison of hair cycle stages is essential, e.g. comparative analysis of gene expression patterns.     

基于单细胞转录组测序技术对鄂尔多斯细毛羊次级毛囊形态发生诱导期的研究

【目的】 试验旨在解析鄂尔多斯细毛羊胚胎期次级毛囊诱导期形态发生过程中主要细胞类型的分子特征和分化过程。【方法】 对采集的3只鄂尔多斯细毛羊（胎龄87 d）体侧部（肩胛骨后缘处）的皮肤样本进行HE染色，鉴定毛囊的发育时期；部分皮肤样本经过混样后进行单细胞转录组测序（scRNA-Seq），应用t-分布随机近邻嵌入（tSNE）分析细胞簇，分别使用胶原Ⅰ型α1链（Col1a1）和角蛋白15（Krt15）鉴定真皮谱系细胞和表皮谱系细胞，并使用皮肤组织不同细胞的标记基因进行细胞类型分析；对测序数据进行拟时序分析，探究其分化过程中差异基因的表达；通过GO功能富集分析进一步验证基因的功能。【结果】 HE染色结果发现，鄂尔多斯细毛羊在胎龄87 d处于次级毛囊诱导期。通过scRNA-Seq在胎龄87 d的细毛羊体侧部皮肤细胞样品中获得10 603个细胞和18 704个基因的scRNA-Seq数据可用于下游分析。tSNE分析发现，皮肤组织中共有15个细胞簇；Col1a1和Krt15标记基因鉴定表明，真皮细胞和表皮细胞具有高度异质性。拟时序分析构建毛囊形态发生过程中真皮/表皮细胞谱系细胞的分化轨迹和基因动态表达图谱表明，在真皮谱系细胞由成纤维细胞（Fb）向成熟真皮聚凝物（DC）的分化过程中，多个不同阶段的标记基因FST重组蛋白（Fst）、抑制素亚基βα（Inhba）和转录阻遏物GATA结合1（Trps1）均在拟时序轨道上特异性表达，并富集了Wnt、Noggin和骨形态发生蛋白（BMP）等与毛囊形态发生相关的信号通路；在表皮谱系细胞分化过程中，基质和毛囊间表皮（IFE）的标记基因角蛋白10（Krt10）、同源基因C13（HOXC13）和音猬因子信号（SHH）在表皮谱系细胞拟时序轨道的2个分支上均特异性表达，且富集在细胞增殖和细胞黏附等相关通路。【结论】 在细毛羊次级毛囊诱导期，真皮谱系细胞由成纤维细胞分化至真皮聚凝物，表皮谱系细胞处于基质和毛囊间表皮细胞增殖分化阶段，结果可加深人们对细毛羊次级毛囊形态发生过程的了解，为鄂尔多斯细毛羊育种研究提供有力的理论和技术支持。     

Generalized alopecic and cystic dermatosis in a cat: a counterpart to the hairless mouse phenotype or a unique congenital dermatosis?

A 2-year-old, male neutered, domestic semi-long-haired cat was presented with a 1.5-year history of progressive, initially nonpruritic alopecia and malodorous greasy exudate affecting the distal extremities, trunk and neck but sparing the head and tail. The extensive alopecia and 'seborrhoea' were associated with severe thickening of the skin and fold formation on the dorsal head and distal extremities as well as the lateral thorax and abdomen. The hair was easily epilated, numerous milia were seen on the ventral abdomen and the caudal and lateral thighs, and mild paronychia was present. Histopathological examination of skin biopsies revealed marked cystic dilation of hair follicles and sebaceous glands with follicular hypoplasia, infundibular hyperkeratosis and variable associated inflammation. Systemic glucocorticoid therapy in combination with topical washes with chlorhexidine and miconazole resulted in a marked improvement and some hair regrowth, but the cat was subsequently lost to follow-up. The dermatosis resembles a number of conditions in other species, but it is not clear whether it is a counterpart to the hairless mutant mouse or is a unique dermatosis.     

An undescribed Demodex sp. and demodicosis in a captive koala (Phascolarctos cinereus).

A 12-yr-old male koala (Phascolarctos cinereus) in a zoo collection developed bilateral, noninflammatory, periocular alopecia. Deep periocular skin scrapings yielded multiple adult, nymphal, and larval mites of a previously undescribed Demodex species. Skin biopsies from affected areas revealed multiple mites in superficial keratin and within hair follicles, associated with a mild intramural lymphocytic folliculitis. Treatment with daily oral ivermectin was safe and effective. Although Demodex sp. are previously reported from skin scrapings in another koala with periocular alopecia, this is the first confirmed case of koala demodicosis.     

Histologic features of hair follicle neoplasms and cysts in dogs and cats: a diagnostic guide

Hair follicle neoplasms occur in many different species, including humans. In domestic animals, they are most common in dogs. Most hair follicle tumors are benign, but malignant neoplasms can also occur. To diagnose hair follicle neoplasms, a thorough knowledge of follicular anatomy is important, given that follicular tumors are classified according to the differentiation pattern seen in the corresponding part of the normal hair follicle. This review focuses on the key diagnostic features of hair follicle tumors and follicular cysts in dogs and cats.     

毛囊发育与周期性生长的调控信号通路研究进展

毛囊是皮肤的重要附属结构,也是控制哺乳动物被毛生长的重要器官。哺乳动物出生后,毛囊具有终生呈周期性生长的特性,毛囊干细胞、毛乳头细胞、毛母质细胞及脂肪细胞等参与了毛囊周期性生长,Wnt、BMP、Notch等信号通路与毛囊生长发育密切相关。本文从哺乳动物毛囊的结构、周期性生长特征以及参与毛囊周期性生长调控的相关信号通路等进行了详细阐述,为深入了解哺乳动物毛囊的周期性生长调控机制,以及为今后指导绒山羊、绵羊、长毛兔等毛用动物和獭兔、水貂、狐狸、貉等皮用动物选育和提高生产性能提供理论参考。     

辽宁绒山羊皮肤毛囊细胞凋亡特点的研究

采用TUNEL法在一个生物年的周期内每隔两月对绒山羊体侧部的皮肤毛囊进行检测,观察毛囊细胞凋亡的周期性变化特点。结果表明,控制毛囊生长变化的凋亡细胞是成簇分布的,毛乳头的成纤维细胞很少有凋亡现象,细胞凋亡与毛囊周期性生长具有相关性,兴盛期毛囊凋亡细胞减少,退行期凋亡细胞显著增多。常年长绒型与季节长绒型品系在一年内的凋亡细胞变化情况基本一致,只是常年长绒型品系在兴盛前期的细胞凋亡明显低于季节长绒型品系。     

Hoxc13在哺乳动物毛囊发育调控中的研究进展

同源盒C13(Hoxc13)基因与毛囊发育和毛发性状的形成密切相关.在哺乳动物毛囊的周期性发育过程中,Hoxc13通过调控角蛋白关联蛋白(KAP)基因等来控制毛囊在生长期、退行期和休止期之间转换,进而直接控制毛发性状的形成和改变,对皮毛动物产业发展具有重要的经济意义.本文围绕Hoxc13的结构特点、生物学功能以及作用机...     

Skin morphology of thyroidectomized rats

We induced hypothyroidism in rats by conducting a thyroidectomy (TD) and investigated subsequent changes in the morphology of the skin, especially that of the epidermis and hair follicles. The 6 rats in the TD group seemed less active than the 3 rats in the control group and had cold, dry paws. All of the rats in the TD group exhibited retarded hair growth 12 weeks after surgery. Histologically, all of the rats in the TD group exhibited epidermal thinning from 12 weeks after surgery. Many hair follicles were in the telogen phase: the bulbs and papillae were involuted and had migrated towards the epidermis. Hair follicle atrophy involving thinning of the outer root sheath and the inner root sheath was often observed. The immunoreactivities of antithyroid hormone receptors alpha and beta in the outer root sheaths of 5 of the TD rats were weaker than those of control rats. Cell proliferation in hair follicles of TD rats was weaker than in follicles of control rats 4 weeks after surgery. It is suggested that decreased expression of TRs and decreased cell proliferation activity in the hair follicles of rats is associated with a lack of thyroid hormone and results in retardation of hair growth.