In vivo reflectance confocal microscopy imaging of vitiligo,nevus depigmentosus and nevus anemicus

Background/purpose: Hypopigmentary skin disorders such as vitiligo, nevus depigmentosus and nevus anemicus are common diseases in clinic. The lesions of these diseases could be similar to some extent, although each of them has its own characteristic clinical appearance and histological features. Clinically, the atypical lesions are often difficult to be differentiated. In vivo reflectance confocal microscopy (RCM) is a non‐invasive, repetitive imaging tool that provides real‐time images at a nearly cellular histological resolution. Our aim was to investigate the RCM features of vitiligo, nevus depigmentosus and nevus anemicus. Subjects and Methods: A total of 135 patients with a clinical diagnosis of the aforementioned diseases were included in this study. The RCM images from depigmented skin, border of the white macules, adjacent normal‐appearing skin and distant normal skin for all patients at the dermo‐epidermal junction (DEJ) level were investigated. Results: In the active phase of vitiligo (AVP), the RCM demonstrated a complete loss of melanin in lesional skin in eight (53; 15.1%) patients. In 45 patients (53; 84.9%) of the AVP, part of the bright dermal papillary rings normally seen at the DEJ level disappeared or part of the rings lost their integrity and the content of melanin decreased obviously. In 20 patients (53; 37.7%) of the AVP, highly refractile inflammatory cells could be seen within the papillary dermis in the lesional and adjacent normal‐appearing skin, which may indicate the lesion progresses. In addition, part of the dermal papillary rings showed lack of integrity or their brightness decreased in adjacent normal‐appearing skin in all the patients of the AVP. It is important to know that the RCM demonstrated an ill‐defined border. In the stable phase of vitiligo (SPV), the RCM demonstrates a complete loss of melanin in lesional skin and a clear border in 31 (41; 75.6%) patients; the content of melanin and dermal papillary rings in adjacent normal‐appearing skin show no changes. In 10 (41; 24.4%) patients, the dendritic and highly refractile melanocytes arose in the recovery phase of vitiligo, which may indicate the repigmentation of vitiligo. There are three kinds of repigmentation patterns under RCM: marginal, perifollicular and diffuse. Distant normal skin showed no difference from controls in both the active and the SPV. In all the patients with nevus depigmentosus, the content of melanin decreases obviously but the dermal papillary rings are intact. The dermal papillary rings show no differences between lesional skin and adjacent normal‐appearing skin of nevus anemicus. Conclusion: Considering our results, RCM may be useful to non‐invasively discriminate vitiligo, nevus depigmentosus and nevus anemicus in vivo.     

几种色素减退性皮肤病的共聚焦激光扫描显微镜图像特点

目的 观察白癜风、无色素痣、进行性斑状色素减少症、贫血痣的活体共聚焦激光扫描显微镜（CLSM）特征。方法 用CLSM观察同一层面（基底层真表皮交界处）皮损处、交界处及白斑周边正常皮肤的镜下特征。结果 进展期白癜风白斑区部分区域色素完全缺失,部分区域可见残存色素环,残存之色素环结构欠完整且色素含量降低;交界处界限模糊;白斑周边正常皮肤可见部分色素环失去完整性。稳定期白癜风白斑处色素完全消失;交界处界限清晰;白斑周边正常皮肤色素环完整,折光明亮;恢复期可见到树突状、折光明亮的黑素细胞。无色素痣和进行性斑状色素减少症的CLSM表现相似：白斑处色素环结构完整,色素含量降低,折光减弱。贫血痣白斑处色素环结构和色素含量与周边正常皮肤无明显差异。结论 结合临床表现,CLSM可以作为鉴别诊断白癜风、无色素痣、进行性斑状色素减少症、贫血痣的一种辅助方法。     

Melasma: histopathological characteristics in 56 Korean patients

BACKGROUND: Melasma is a common acquired symmetrical hypermelanosis characterized by irregular light to dark brown macules and patches on sun-exposed areas of the skin. Its histopathological characteristics are not fully understood. OBJECTIVES: To characterize the histopathological features of facial melasma skin in comparison with adjacent normal skin. METHODS: Biopsies were taken from both melasma lesional skin and adjacent perilesional normal skin in 56 Korean women with melasma. The sections were stained using haematoxylin and eosin, Fontana-Masson, diastase-resistant periodic acid-Schiff, Masson trichrome and Verhoeff-van Gieson stains, and immunostaining for melanocytes. Data on the changes in number of melanocytes and melanin contents of the epidermis were analysed by a computer-assisted image analysis program. The ultrastructure of the skin was also examined. RESULTS: The amount of melanin was significantly increased in all epidermal layers in melasma skin. The staining intensity and number of epidermal melanocytes increased in melasma lesions. Lesional skin showed more prominent solar elastosis compared with normal skin. Melanosomes increased in number and were more widely dispersed in the keratinocytes of the lesional skin. Lesional melanocytes had many more mitochondria, Golgi apparatus, rough endoplasmic reticulum and ribosomes in their cytoplasm. A dihydroxyphenylalanine reaction was apparent in the cisternae and vesicles of the trans-Golgi network in melanocytes from lesional skin. CONCLUSIONS: Melasma is characterized by epidermal hyperpigmentation, possibly caused both by an increased number of melanocytes and by an increased activity of melanogenic enzymes overlying dermal changes caused by solar radiation.     

Pigmentary disorders in oriental skin

Brown hyperpigmented disorders may be melanotic in which there is a normal number of epidermal melanocytes but melanin pigment is increased in the epidermis (eg, melasma), melanocytotic, in which melanocytes are increased (eg, café-au-lait macules), and nonmelanotic hyperpigmentation (eg, minocycline pigmentation). Blue hyperpigmented disorders may also be melanotic in which there is a normal number of epidermal melanocytes, but melanin pigment is present in the upper dermis (eg, gray/slate pigmentation in Riehl's melanosis), melanocytotic in which melanocytes are present in both the epidermis and dermis (eg, blue pigmentation in Nevus Ota and Mongolian spot), and nonmelanotic hyperpigmentation in which pigment is present in the deep dermis (eg, blue pigmentation in tattoos). Hypomelanosis (leukoderma) may be divided histopathologically into melanocytopenic disorders on which melanocytes are absent (eg, Vogt-Koyanagi-Harada syndrome and vitiligo), melanopenic disorders in which melanocytes are present but melanin is reduced (eg, nevus depigmentosus and incontinentia pigmenti achromians), and nonmelanotic disorders in which melanin pigmentation is unaffected (nevus anemicus) and the pigmentary abnormality is caused by something other than melanin. There are numerous pigmentary disorders in the oriental skin, and some of them are either characteristic to or established in the orientals. Importantly, a number of congenital hypermelanotic and hypomelanotic diseases (eg, nevus depigmentosus, incontinentia pigmenti, and incontinentia pigmenti achromians, take a distribution following to the Blaschko's line.     

Behavior of pigment cells on lesions of the pigmented venus with vitiligo.

When vitiligo occurred on lesions of the pigmented nevus, the behavior of pigment cells in this nevus was investigated. Three cases of giant hairy nevi, seven cases of moles, three cases of Mongolian spots and eleven specimens in nine cases of halo nevi were used. Giant hairy nevi combining with vitiligo showed intensive decreases in nevus cells, particularly superficial A and B-type nevus cells. The epidermal dopa-positive melanocytes and melanin granules in the epidermis decreased, but still remained. On the other hand, moles in vitiligo showed an almost complete disappearance of epidermal dopa-positive melanocytes and melanin granules in the epidermis; nevus cells in the dermis decreased only slightly. Mongolian spots with vitiligo showed an epidermis similar to vitiligo, but the dermal melanocytes were hardly changed. Halo nevi exhibited an intensive decrease and degeneration of nevus cells and marked lymphocytic infiltration. Some of them showed disappearance of epidermal dopa-positive melanocytes and melanin granules in the epidermis. The characteristic findings of vitiliginous skin are mostly restricted to epidermis. In contrast, however, it is interesting to note that, on the lesions of nevocellular nevi with vitiligo, the dermis also exhibited some decrease and degeneration of nevus cells and lymphocytic infiltration.     

无色素痣的临床、组织学和超微结构观察

目的 探讨无色素痣的临床和组织学特征。方法 分析85例无色素痣患者的发病年龄、类型和皮损特点,并对部分患者行皮肤色素测定和反射式共聚焦显微镜（RCM）观察。对其中17例患者的皮损区和正常区皮肤组织进行组织病理检查,透射电镜观察皮损区超微结构。免疫组化法检测皮损区和正常皮肤处酪氨酸酶（TYR）、HMB45、酪氨酸酶相关蛋白1（TRP-1）、TRP-2和CD117表达。结果 85例无色素痣患者中,23例（27.1%）出生时发现皮损,21例（24.7%）出现于3岁以后,最大发病年龄为29岁。皮损分布于躯干部25例（29.4%）,颈部13例（15.3%）;72例（84.7%）皮损边缘不规则,54例（63.5 %）仅有1处皮损。19例无色素痣患者患处的黑素指数（186.56 ± 52.86）和相对黑素指数（80 ± 11）低于正常人皮肤（分别为223.88 ± 63.19和100）,高于12例白癜风患者皮损处（分别为128.57 ± 64.31和60 ± 20）,差异均具有统计学意义（P < 0.01）。反射式共聚焦显微镜示,无色素痣皮损中含黑素细胞数量减少,亮度减低,黑素分布均匀,皮损区与正常皮肤分界区常不清晰。皮损区Fontana-Masson染色示皮损区黑素强度为1810.12 ± 327.96,较正常区（2064.24 ± 260.41）明显减弱。电镜下发现黑素细胞数量减少,黑素小体减少,黑素细胞胞质和树突以及角质形成细胞中可见Ⅱ、Ⅲ期未成熟的黑素小体,角质形成细胞中可见聚集成团的黑素小体。17例患者正常区TYR表达水平为1827.35 ± 307.09,TRP-1为6102.54 ± 1642.64,而皮损区TYR（1477.35 ± 224.05）和TRP-1（5322.33 ± 1565.26）表达下降,正常区与皮损区比较,P均 < 0.01;HMB45、TRP-2、CD117表达两处比较差异均无统计学意义。 结论 无色素痣是一种早期发病、非家族聚集性、稳定的不规则色素减退性疾病,其皮损中黑素细胞和黑素小体数量均减少,可见未成熟黑素小体。相对黑素指数和反射式共聚焦显微镜检查可作为诊断无色素痣的无创性检测方法。     

白癜风表皮黑素细胞超微结构及小眼畸形相关转录因子转录调控研究

目的 研究白癜风黑素细胞超微结构和小眼畸形相关转录因子 （MITF）及其转录调控的酪氨酸酶相关蛋白（TRP）与白癜风临床类型与病程的相关性。方法 选择不同病程的寻常型白癜风（VV）12例和节段型白癜风（SV）8例,分别取白斑区、白斑边缘正常肤色区和远离白斑正常肤色区的表皮片,经组织学确定其表皮的完整性。透射电镜观察10例患者（VV 6例,SV 4例）不同区表皮黑素细胞的超微结构特点。对所有20例远离白斑正常肤色区的表皮片黑素细胞进行培养,应用免疫印迹方法检测 MITF及其转录调控的酪氨酸酶（TYR）、酪氨酸酶相关蛋白1（TYRP1）和酪氨酸酶相关蛋白2（TYRP2）的表达水平。结果 白癜风表皮黑素细胞超微结构病理改变：10例中7例白斑区表皮内未见黑素细胞,1例短病程和2例长病程VV分别可见少量黑素体显著减少或缺失的黑素细胞;白斑边缘正常肤色区,6例VV中,3例病程小于15个月者可见黑素细胞超微结构异常,而4例SV中仅1例异常;远离白斑正常肤色区,10例黑素细胞超微结构均正常。白癜风表皮黑素细胞MITF及其转录调控TRP的表达：VV的MITF表达下调与TYR、TYRP1、TYRP2的表达下调一致;SV存在MITF显著表达下调,而TYR、TYRP1、TYRP2几均正常表达。结论 VV和SV可能存在不同的表皮黑素细胞超微结构病理改变和MITF转录调控机制。     

体外培养节段型白癜风样无色素痣皮损黑素细胞及其临床意义

【摘要】 目的 评价负压吸疱表皮黑素细胞培养对节段型白癜风样无色素痣的辅助诊断价值。方法 收集2019年6月至2020年3月于杭州市第三人民医院皮肤科依据Coupe标准临床诊断的8例节段型白癜风样无色素痣患者,进行伍德灯、反射式共聚焦显微镜（RCM）检查,308 nm准分子激光试验,负压吸疱获取表皮黑素细胞并培养,记录结果。结果 8例患者中,6例皮损伍德灯下可见荧光,4例RCM下可见色素环完整性缺失,5例经308 nm准分子激光照射试验后未见复色反应。8例患者体外培养的皮损黑素细胞硫酸亚铁染色均阳性,经消化离心后沉淀呈黄白色,电镜下黑素细胞胞质内可见Ⅰ~ Ⅲ期黑素小体;皮损对侧同一解剖部位正常皮肤黑素细胞沉淀则呈黑色,电镜下黑素细胞胞质内可见Ⅰ~ Ⅳ期黑素小体。结论 负压吸疱表皮黑素细胞培养有助于诊断节段型白癜风样无色素痣。     

Clinical differences between segmental nevus depigmentosus and segmental vitiligo

Segmental nevus depigmentosus and segmental vitiligo can be difficult to differentiate from each other. Differential diagnosis of these two diseases is important because they have significantly different prognoses and psychological effects. The purpose of this study is to identify clinical clues that may be helpful in differentiating these two diseases. We enrolled 63 patients with segmental nevus depigmentosus and 149 patients with segmental vitiligo. Sex, age of onset, sites involved, dermatomal distribution, margin of lesion and presence of poliosis were evaluated in both groups. The age of onset was less than 10 years in 96.8% of segmental nevus depigmentosus and 28.9% of segmental vitiligo cases. Trunk (36.5%) and cervical (38.1%) dermatomes were the most commonly involved in segmental nevus depigmentosus and face (67.1%) and trigeminal (64.4%) dermatomes in segmental vitiligo. The average number of dermatomes involved in truncal lesions was different in segmental nevus depigmentosus and segmental vitiligo (2.71 vs 1.62, P = 0.001). Segmental vitiligo on the face, neck and trunk appeared closer to the axis than segmental nevus depigmentosus (P < 0.001). Segmental nevus depigmentosus and segmental vitiligo showed significantly different margins (90.5% and 41.6% serrated, respectively; P < 0.001). We observed clinical differences between patients with segmental nevus depigmentosus and those with segmental vitiligo. Distribution (site, distance to axis, dermatome), vertical width, margin of lesion and presence of poliosis can be helpful in differentiating segmental nevus depigmentosus and segmental vitiligo.     

Clinical and histopathologic characteristics of trichrome vitiligo

BACKGROUND: The term trichrome vitiligo describes lesions that have a tan zone of varying width between normal and totally depigmented skin, which exhibits an intermediate hue. However, the pathogenesis and the histopathologic characteristics of trichrome vitiligo are unknown. OBJECTIVE: Our purpose was to investigate the clinical and histopathologic characteristics and the pathogenesis of trichrome vitiligo. METHODS: Four punch biopsy specimens were taken from 21 patients with trichrome vitiligo; they were from vitiliginous skin, light brown skin, perilesional normal skin, and normal skin as far as 5 cm from the nearest vitiligo spot. The sections were stained with hematoxylin-eosin; in selected cases, we performed immunohistochemical staining with S-100 protein and CD1a. RESULTS: Trichrome vitiligo occurred most frequently on the trunk in active vitiligo vulgaris. Focal vacuolar degeneration of the basal cell layer and mild inflammatory cell infiltration of the epidermis and dermis were more prominent in light brown skin and perilesional normal skin than in vitiliginous skin and normal skin. The number of melanocytes was decreased in light brown skin compared with perilesional normal skin (P <.05) and in vitiliginous skin compared with light brown skin (P <.05); a few melanocytes were observed even in skin affected by trichrome vitiligo. The number of Langerhans cells was increased in the epidermis of light brown skin and perilesional normal skin compared with vitiliginous and normal skin (P <.05). PUVA therapy yielded excellent repigmentation. CONCLUSION: Trichrome vitiligo is a variant of active vitiligo. The changes of melanocytes, keratinocytes, and Langerhans cells may be involved in the pathogenesis of depigmentation in trichrome vitiligo.     

Perilesional vs. lesional skin changes in senile lentigo

BACKGROUND: Senile lentigo (SL) is a common component of photoaged skin. It is characterized by hyperpigmented macules which affect chronically irradiated skin mostly after 50 years of age. This study was undertaken to assess the basic morphology of SL on dorsum of hands. METHODS: A systematic comparison between lesional vs. perilesional skin using immunohistochemistry and electron microscopy was done to detect precursor lesions of SL and to determine whether melanocytes or keratinocytes were first affected in the evolution of lesions. RESULTS: In 12 cases studied, the main findings show that clusters of perilesional keratinocytes accumulate melanin in large melanosomial complexes, and that melanocytes counts are increased respective to total length of section in lesional skin, but the increment is probably due to the development of characteristic epidermal rete ridges. Melanocytes had overall a normal ultrastructure, with mostly quiescent features in perilesional skin and melanosomial transport seeming more active in lesional skin. CONCLUSIONS: Our data indicate that SL may represent a loss of epidermal melanin unit homeostasis due to chronic irradiation, where keratinocytic changes predominate over melanocytic changes. We hypothesize that abnormal pigment retention in keratinocytes is the primary defect in SL, which may partly explain the therapeutic effect of retinoids.     

Study of CCN3 (NOV) and DDR1 in normal melanocytes and vitiligo skin

We have hypothesised that melanocytes disappear in vitiligo because they are weakly attached to the epidermal basal membrane (melanocytorrhagy). In the epidermis, attachment of melanocytes to collagen IV is mediated through DDR1, which is under the control of CCN3. DDR1 genetic variants have been associated with vitiligo in patients of different ethnic origin. In vitro studies have shown that inhibition of CCN3 induces the detachment of melanocytes. We have studied in parallel the expression of CCN3 and DDR1 in lesional and perilesional skin of patients with vitiligo and the impact of the silencing of CCN3 and DDR1 in normal human melanocytes on their behaviour in epidermal reconstructs. Our in vivo study provides evidence of a dysregulation of the DDR1-CCN3 interaction in vitiligo skin as melanocytes remaining in perilesional skin did not express CCN3. Expression of DDR1 was decreased in lesional versus perilesional vitiligo skin in the majority of patients, and the expression of collagen IV was found decreased in all patients. Silencing of CCN3 in melanocytes induced a significant inhibition of cell adhesion to collagen IV whereas melanocytes transduced with shDDR1 still adhered well on collagen IV and did not increase melanocyte loss in epidermal reconstructs as compared with normal melanocytes. Melanocyte detachment was observed but not in all reconstructs using CCN3 silenced melanocytes. Overall, our study confirms that a downregulation of CCN3 is implicated in melanocyte adhesion in part through DDR1. In vitiligo skin, the interaction of CCN3 with other molecules, such as TGFβ and CCN2, needs to be addressed.     

The expression of the c-kit receptor by epidermal melanocytes may be reduced in vitiligo

Summary The proto-oncogene c-kit encodes the transmembrane tyrosine kinase receptor that has a role in the growth regulation of various cell types including melanocytes. In the present study we have examined the expression of the c-kit protein in the skin of seven patients with vitiligo. Melanocytes positive for c-kit protein were observed in the basal layer in non-lesional skin and the mean number of 25.8 ± 5·2 (per 200 basai ceils) compared with that of 21·8 ± 3·5 from six control subjects. In perilesional skin there was a reduction in the numbers of c-kit positive melanocytes (6·7±2·6) and this was especially noticeable in six of the seven patients. Such a reduction was less obvious following staining with MEL-5 and in only two subjects were the numbers of melanocytes below the normal range. This suggests that the reduction in c-kit staining was the result of decreased expression of the protein rather than a loss of melanocytes. No melanocytes. positive for c-kit protein, or after staining with MEL-5. were identified in lesional skin although isolated tyrosinase-positive melanocytes were seen in one subject. There was no apparent change in the numbers of mast ceils expressing c-kit protein and the intensity of staining in the dermis even in lesional skin was similar to that in the controls. These results demonstrate that c-kit protein is present on melanocytes in adult human skin and that in perilesional skin of some vitiligo patients there is a reduction in the numbers of melanocytes expressing this receptor. Whether this may contribute to the defective melanocyte growth and/or survival that occurs in vitiligo or whether it is a consequence of melanocyte damage remains to be seen.     

Possible mechanisms of hypopigmentation in lichen sclerosus

Lichen sclerosus (LS) shares with vitiligo a milky-white appearance. By biopsy, pathognomonic dermal sclerosis readily distinguishes LS from vitiligo and other causes of leukoderma. To determine what the mechanism of hypopigmentation is in LS, we examined samples from LS cases for alterations in melanin content (Fontana-Masson stain) and melanocyte number (HMB-45 [PMEL-17/gp100], Mel-5 [TRP-1], Mart-1 [Melan A]) and compared these findings with those in controls of normal skin, acute scars, vitiligo, and lichen planus (LP; a common inflammatory cause of hyperpigmentation). The degree and extent of melanization found in LS overlapped with that in acute scars showing predominantly hypomelanized keratinocytes, with that in LP containing regions with numerous melanophages, and with that in vitiligo exhibiting focal regions of keratinocytes devoid of melanin pigment. By hematoxylin-eosin staining and immunocytochemistry for Mel-5 and Mart-1, LS had a lower mean count of melanocytes than acute scars, LP, and normal skin per 200 basal keratinocytes. In addition, a few LS cases had a significant loss of melanocytes comparable to that of vitiligo. Surprisingly, Mart-1 identified rare melanocytes in 67% of vitiligo cases and a significantly larger pool of melanocytes in LS and controls other than those labeled by Mel-5. Furthermore, LP and evolving lesions of LS contained the highest Mart-1 counts. HMB-45-immunoreactive melanocytes were found in the majority of acute scars and in LP and late-stage LS lesions at significantly lower levels than Mel-5- and Mart-1- labeled melanocytes, but they were not found in vitiligo or normal skin. We propose that several mechanisms may play a role in the production of leucoderma in LS: 1) decreased melanin production; 2) block in transfer of melanosomes to keratinocytes; and 3) melanocyte loss. The latter finding may be the pathogenic connection (lichenoid dermatitis of LS triggering an autoimmune reaction to melanocytes) that underlies the documented association of LS with vitiligo.     

Aberrant expression of complement regulatory proteins, membrane cofactor protein and decay accelerating factor, in the involved epidermis of patients with vitiligo

BACKGROUND: Vitiligo is a pigmentary disorder of the skin characterized by the complete absence of melanocytes from the lesion. Complement-activating antimelanocyte antibodies have been implicated in vitiligo pathogenesis. As membrane regulators of complement activation, membrane cofactor protein, decay accelerating factor and CD59 protect cells from elimination by autologous complement, their absence or downregulation on melanocytes may be associated with autoantibody and complement-mediated melanocyte destruction in vitiligo. OBJECTIVES: We studied the expression of these regulatory proteins in non-lesional, perilesional and lesional vitiligo skin compared with those of control specimens. METHODS: We used immunohistochemistry to study the expression of the regulatory proteins, and flow cytometric analysis of cultured melanocytes to investigate possible constitutive changes in the expression levels of these molecules. We also investigated whether melanocytes can influence keratinocyte susceptibility to autologous complement by regulating keratinocytic decay accelerating factor and membrane cofactor protein expression levels. RESULTS: Immunohistochemical data showed that expression of membrane cofactor protein and decay accelerating factor in whole epidermis was lower in lesional and perilesional skin in comparison with non-lesional skin. The reduced in situ expression appeared to be specific to vitiligo. However, coculture experiments indicated that melanocytes do not influence keratinocyte susceptibility to autologous complement. Further, flow cytometric analysis of cultured melanocytes convincingly demonstrated that non-lesional vitiligo and control melanocytes have comparable decay accelerating factor, membrane cofactor protein and CD59 expression levels. CONCLUSIONS: It is therefore concluded that there is no constitutive melanocyte defect per se that could be related to the in vivo expression of these molecules in vitiligo. Nevertheless, the present data suggest that both keratinocytes and melanocytes in the involved vitiliginous whole epidermis express lower levels of decay accelerating factor and membrane cofactor protein compared with controls that could render them more vulnerable to autologous complement attack.     

In vitro growth characteristics of melanocytes obtained from adult normal and vitiligo subjects

The in vitro growth characteristics of melanocytes obtained from uninvolved and perilesional skin of vitiligo vulgaris subjects have been investigated in comparison to those from healthy adult donors. Normal human melanocytes have been found to grow exponentially in the presence of 10(-11) M cholera toxin and 10 ng/ml of 12-O-tetradecanoylphorbol-13-acetate in routine tissue culture media. They could be trypsinized up to 3-4 passages. Melanocytes of the uninvolved skin of vitiligo subjects manifested a lag of 8-11 days for the onset of growth and they could not be passaged. Melanocytes obtained from both hypo- and hyper-pigmented perilesional skin failed to grow under these conditions. Only in a few cases where the perilesional skin was normally pigmented did the melanocytes manifest some growth after a lag of 15 days. The initial seeding capacity of the melanocytes from uninvolved and perilesional skin of vitiligo patients were, respectively, 50% and 25% of the normal individuals. Vitiligo lesions themselves gave rise to unidentified dendritic cells that survived for 10-15 days without manifesting any growth. Our results suggest that melanocytes of individuals with vitiligo are defective. This fact has to be taken into account in any theory on the etiology of vitiligo.     

Abnormal nuclear expression of aquaporin-3 in lesional and perilesional skin of vitiligo patients: A novel immunohistochemical finding

Background

Vitiligo is a skin disease characterized by a complex etiopathogenesis. Keratinocyte apoptosis may play a role in vitiligo pathogenesis. Aquaporin-3 (AQP-3) is an aqua-glyceroporin that controls keratinocyte proliferation and differentiation.

Aim

To assess the immunohistochemical expression of AQP-3 in lesional and perilesional skin of vitiligo patients compared to healthy control skin.

Methods

A total of 20 patients with generalized non-segmental vitiligo and 20 age- and sex-matched healthy controls were included. Lesional and perilesional skin of vitiligo patients, as well as normal skin of control subjects, were biopsied. The immunohistochemical expression of AQP3 in the epidermis was examined.

Results

Compared to control skin, both lesional and perilesional skin showed a significant reduction in the intensity of membranous staining of AQP-3 (p < 0.001, p = 0.002, respectively). Moreover, the membrano-cytoplasmic pattern of AQP-3 staining was significantly detected in 80% of lesions and 85% of perilesional biopsies, while it was absent in control skin (p < 0.001). Additionally, nuclear AQP-3 expression was significantly detected in 35% of lesions and 55% of perilesional biopsies, while it was not detected in control skin (p = 0.012, p < 0.001, respectively). No statistically significant difference was detected between lesional and perilesional skin.

Conclusions

To our knowledge, this is the first immunohistochemical research to show a significant abnormal nuclear expression of AQP-3 in lesional and perilesional skin of vitiligo patients. This abnormality may reflect impaired functions of AQP-3, leading to keratinocyte apoptosis with subsequent melanocyte death and development of vitiligo.     

白癜风皮损边缘黑素细胞线粒体超微结构的电镜观察

【摘要】 目的 探讨白癜风患者皮损边缘黑素细胞线粒体结构的变化。方法 在透射电镜下观察健康对照、进展期白癜风及稳定期白癜风患者皮损边缘黑素细胞形态,体视学方法测量线粒体体密度（Vv）、表面积密度（Sv）、数密度（Nv）等参数。结果 健康对照组黑素细胞可见大量黑素小体（28.57 ± 3.21）,以Ⅲ、Ⅳ期为主,线粒体规则分布在细胞内,结构正常、嵴密集,部分细胞胞质内可见自噬小体。进展期和稳定期白癜风黑素细胞内黑素小体数量减少,单位细胞内黑素小体数量分别为22 ± 6.16和17.43 ± 6.24,其中,Ⅲ期黑素小体显著减少,线粒体大小不一、形态多样,大部分线粒体明显肿胀,嵴模糊、排列紊乱甚至断裂,呈空泡状改变,未见线粒体自噬现象。线粒体形态结构定量研究显示,健康对照组Nv、Vv、Sv分别为（7.194 ± 1.434） μm－3、（4.8 ± 1.2）%、（2.42 ± 0.86） μm－1;进展期白癜风组Nv、Vv、Sv分别为（4.055 ± 0.906） μm－3、（7.4 ± 2.1）%、（3.58 ± 1.15） μm－1;稳定期白癜风组Nv、Vv、Sv分别为（5.311 ± 0.873） μm－3、（6.5 ± 1.4）%和（2.82 ± 0.94） μm－1,组间差异有统计学意义（P ＜ 0.05）。结论 白癜风皮损边缘黑素细胞线粒体受损,且进展期损伤程度大于稳定期。 【关键词】 白癜风; 黑素细胞; 线粒体; 显微镜检查,电子,透射     

胶带粘贴法观察窄谱中波紫外线治疗后白癜风皮损的复色

目的 探讨窄谱中波紫外线（NB-UVB）治疗前后照射区浅表角质层细胞中黑素颗粒的变化。 方法 使用胶带粘贴法对接受NB-UVB治疗的白癜风皮损进行浅表角质层细胞取样,银氨染色后观察细胞中黑素颗粒形态、分布、颜色的变化,使用Image-Pro Plus6.0显微图像分析软件计算细胞内黑素颗粒面积百分比,使用SPSS11.5对数据进行统计分析。 结果 治疗前白斑区仍残存少量含黑素颗粒的浅表角质层细胞。治疗前黑素颗粒面积百分比为（5.31 ± 4.12）%,治疗10次后为（6.24 ± 2.65）%,治疗20次后为（10.14 ± 5.73）%,治疗30次后为（13.05 ± 6.17）%,方差分析显示,治疗前、治疗10次、治疗20次、治疗30次后黑素颗粒面积百分比差异有统计学意义（F = 4.334,P < 0.05）,经两两比较分析,治疗30次后细胞内黑素颗粒面积百分比相对治疗前及治疗10次后均增高（P值均 < 0.01）。皮损复色区新生黑素颗粒染色后形态、颜色与治疗前周边正常肤色区有所不同。结论 用浅表角质层细胞胶带粘贴法可以客观评估NB-UVB治疗白癜风的复色过程。     

Role of apoptosis and melanocytorrhagy: a comparative study of melanocyte adhesion in stable and unstable vitiligo

Background Apoptosis and melanocytorrhagy have been proposed as mechanisms of melanocyte disappearance although there are few controlled studies. Objectives We undertook this project to study melanocyte morphology and adhesion defects in patients with stable and unstable disease in controls. Methods In this comparative study we included seven patients with stable disease and seven patients with unstable vitiligo. We cultured perilesional skin melanocytes from these patients with stable and unstable vitiligo and studied for morphological changes, adhesion to collagen type IV and caspase 3 expression. Melanocytes were also treated with okadaic acid and annexin V expression was then checked and compared between controls and patients with stable and unstable vitiligo. Results Perilesional skin melanocytes from patients with unstable vitiligo revealed some significant morphological changes. Melanocytes from unstable vitiligo showed significantly low adhesion to collagen type IV compared with control and stable vitiligo melanocytes. Our results showed that caspase 3 and annexin V staining was significantly greater in melanocytes cultured from unstable vitiligo compared with the control. Conclusions In this study we demonstrated that melanocytes in the patients with unstable vitiligo were in their detachment phase, which ultimately leads to apoptosis of these cells, whereas melanocytes cultured from controls and from patients with stable vitiligo were morphologically normal without any adhesion defects. These morphological and adhesion findings support the theory of melanocytorrhagy as the primary defect underlying melanocyte loss in unstable vitiligo.