Spontaneous atopic dermatitis-like symptoms in a/a ma ft/ma ft/J flaky tail mice appear early after birth

Loss-of-function mutations in human profilaggrin gene have been identified as the cause of ichthyosis vulgaris (IV), and as a major predisposition factor for atopic dermatitis (AD). Similarly, flaky tail (a/a ma ft/ma ft/J) mice were described as a model for IV, and shown to be predisposed to eczema. The aim of this study was to correlate the flaky tail mouse phenotype with human IV and AD, in order to dissect early molecular events leading to atopic dermatitis in mice and men, suffering from filaggrin deficiency. Thus, 5-days old flaky tail pups were analyzed histologically, expression of cytokines was measured in skin and signaling pathways were investigated by protein analysis. Human biopsies of IV and AD patients were analyzed histologically and by real time PCR assays. Our data show acanthosis and hyperproliferation in flaky tail epidermis, associated with increased IL1β and thymic stromal lymphopoietin (TSLP) expression, and Th2-polarization. Consequently, NFκB and Stat pathways were activated, and IL6 mRNA levels were increased. Further, quantitative analysis of late epidermal differentiation markers revealed increased Small proline-rich protein 2A (Sprr2a) synthesis. Th2-polarization and Sprr2a increase may result from high TSLP expression, as shown after analysis of 5-days old K14-TSLP tg mouse skin biopsies. Our findings in the flaky tail mouse correlate with data obtained from patient biopsies of AD, but not IV. We propose that proinflammatory cytokines are responsible for acanthosis in flaky tail epidermis, and together with the Th2-derived cytokines lead to morphological changes. Accordingly, the a/a ma ft/ma ft/J mouse model can be used as an appropriate model to study early AD onset associated with profilaggrin deficiency.

Common FLG mutation K4671X not associated with atopic dermatitis in Han Chinese in a family association study

BACKGROUND

Filaggrin gene (FLG) mutations have been identified as the cause of ichthyosis vulgaris (IV) and major predisposing factors for atopic dermatitis (AD). The relationship among AD, IV and FLG mutations has not been clarified yet. Mutations 3321delA and K4671X, two of the most common mutations in Chinese patients, were both statistically associated with AD in case-control studies.

MATERIALS AND METHODS

A group of 100 family trios (a total of 300 members with one affected AD proband and both parents) were recruited and screened for three filaggrin null mutations (3222del4, 3321delA and K4671X). The subjects' manifestations of AD and IV were assessed by two experienced dermatologists and recorded in detail. The relationship of common mutations to AD were assessed using both case-control and family-based tests of association. Filaggrin expression was measured in skin of 3 subjects with K4671X heterozygote and the normal control using quantitative real-time RT-PCR and immunohistochemistry.

RESULTS

Of 100 probands for AD, 22 were carriers for common FLG mutations and only 2 of them were from 40 none-IV family trios (5.00%), consistent with that of the healthy control group (3.99%, P>0.05). Significant statistical associations were revealed between AD and 3321delA (P<0.001, odds ratio 12.28, 95% confidence interval 3.35-44.98) as well as K4671X (P = 0.002, odds ratio 4.53, 95% confidence interval 1.77-11.60). The family-based approach revealed that 3321delA was over-transmitted to AD offspring from parents (T:U = 12∶1, P = 0.003) but failed to demonstrate transmission disequilibrium between K4671X and AD (T:U = 10∶8, P = 0.815). Moreover, compared to the normal control, filaggrin expression at both mRNA and protein levels in epidermis of subjects with K4671X(heter) was not reduced.

CONCLUSIONS

AD patients from none-IV family trios have low probability of carrying FLG mutations. The present family samples confirmed the susceptibility of mutation 3321delA to AD in Han Chinese. K4671X was not a pathogenic mutation.

Efficacy of topical 10% urea-based lotion in patients with ichthyosis vulgaris: a two-center, randomized, controlled, single-blind, right-vs.-left study in comparison with standard glycerol-based emollient cream

BACKGROUND

Ichthyoses are genetic disorders of keratinization which are uncomfortable due to their conspicuous scaling, itching and cosmetic problems. Ichthyoses can lead to social discrimination and psychological problems. Ichthyosis vulgaris (IV) is the most common form of these geno-dermatoses. IV is a chronic disorder that often requires continuous therapy. Emollient and keratolytic products are the mainstay treatments of IV. It is important that efficient, safe and well tolerated therapies should be available. Direct comparative data regarding efficacy of different emollient products in IV patients are very few.

OBJECTIVE

The aim of the study was to investigate the keratolytic and moisturizing properties as well as the tolerance of a new urea topical formulation (Ureadin Rx10) when applied to hyperkeratotic and dry skin in patients with (IV) in comparison with a standard emollient cream.

METHODS

The study was conducted as a two-center, randomized, controlled, single-blind, intra-patient (right-vs.-left) trial design. A total of 30 patients with IV between 8 and 65 (mean age: 25 years) treated with a 10% urea-based lotion, Ureadin Rx 10 * *Ureadin RX 10 is a registered trade name of ISDIN, Spain. (URx), for 4 weeks or a glycerol-based emollient cream, Dexeryl † †Dexeryl is a registered trade name of Pierre Fabre Dermatologie. (DC), in a right-vs.-left study design. Primary outcome was a 5-point SRRC Index score (evaluating scaling roughness, redness and cracks) evaluated at baseline and after 2 and 4 weeks of treatment. As secondary endpoints patients evaluated also the global efficacy (GE) and global tolerability (GT) scores with the help of a 10 cm visual analogue scale (0 = no efficacy at all/very bad tolerability; 10: excellent efficacy/excellent tolerability).

RESULTS

At baseline the mean (SD) SRRC score was 9.5 (1.9) in the URx treated sites and 9.5 (1.9) in the DC treated sites. A total of 27 patients (90%) concluded the study period. Three patients were withdrawn prematurely because of itching and burning sensation after DC application (1 patient) or URx application (2 patients). At week 4, in comparison with baseline values, both treatments were shown to be clinically effective: SRRC significantly (p = 0.0001) decreased to 3.3 (1.8) after URx (a 65% relative reduction) and to 5.7 (2.5) after DC (a 40% relative reduction). SRRC was significantly lower in URx treated regions in comparison with DC both after 2 and 4 weeks of treatment (p = 0.0005). Mean GE score in areas treated with URx was significantly (p = 0.0001) higher than in the areas treated with the DC (8.9 vs.7.3). Both treatments were in general well tolerated. GT score was 8.1 (range 10 to 3) with URx and 8.4 (range 10 to 3) with DC application (p = ns). The two main limitations of this trial are the study design (single blind), and the small sample size which is not adequate for an evaluation of safety.

CONCLUSION

Ureadin Rx 10 lotion has shown a greater efficacy on ichthyosis vulgaris in term of reduction of scaling, roughness, redness and cracking in comparison with a glycerol-based emollient cream. Tolerability of the two topical treatments was comparable. Further studies with larger sample sizes are needed for the evaluation of safety and tolerability of urea 10% lotion in this clinical setting.

A pilot trial of dermoscopy as a rapid assessment tool in pediatric dermatoses

Dermoscopy is a noninvasive technique to assess skin architecture. A pilot study was conducted using polarized dermoscopy as a tool to monitor the pediatric skin barrier. Ten pediatric patients (age range, 1-14 years) with mild to moderate atopic dermatitis (AD), ichthyosis vulgaris (IV), and/or keratosis pilaris (KP) participated in a 4-week clinical trial. After a week of emollient usage alone, a mid-potency topical corticosteroid cream was added twice daily if necessary to treat erythema, dermatitis, or pruritus. The participants were assessed at weeks 0, 1, and 4 using the eczema area and severity index (EASI) for atopic dermatitis, investigator global assessment for atopic dermatitis, children dermatology life quality index (CDLQI), and clinical and dermoscopic photography. Dermoscopic appearance demonstrated dermal vascular ectasia in AD and KP, hyperkeratosis and prominence of the interkeratinocyte space in AD and IV and widening of the follicular orifice in KP. Improvements in these dermoscopic abnormalities were noted after emollient usage, mirroring improvements in clinical appearance, EASI, and CDLQI. Dermoscopy is a promising tool to assess localized improvement in skin architecture in pediatric dermatoses. Further studies and development of scoring systems will be needed to apply this technology to clinical practice.

[Mutations in the gene encoding filaggrin cause ichthyosis vulgaris]

Ichthyosis vulgaris is a common genetic skin disorder with an estimated prevalence of 1:250 caused by mutations in the gene encoding filaggrin. This disorder manifests itself within the first year of life and is clinically characterized by dry, scaly skin, keratosis pilaris, palmar hyperlinearity and atopic manifestations. Patients with a severe phenotype are homozygous or compound heterozygous for the mutations, whereas heterozygous patients show mild disease, suggesting semidominant inheritance with incomplete penetrance. We present a patient with classic severe ichthyosis vulgaris, atopic eczema and two loss-of-function mutations.

Filaggrin mutations p.R501X and c.2282del4 in ichthyosis vulgaris

Ichthyosis vulgaris (IV) is the most common hereditary disorder of cornification in humans, characterized by generalized fine scaling of the skin, palmar hyperlinearity with or without keratosis pilaris and atopy. Recently, the molecular basis of IV was ascribed to loss-of-function mutations in the gene encoding filaggrin (FLG), namely p.R501X and c.2282del4. Homozygotes and compound heterozygotes were severely affected whereas heterozygotes showed mild disease or were asymptomatic, suggesting semidominant inheritance with incomplete penetrance in heterozygotes. We report the presence of FLG mutations in 15 out of 21 IV patients with a marked generalized scaling phenotype, including eight affected members of a four-generation family. In this group of patients not only homozygous and compound heterozygous, but also heterozygous patients for p.R501X and c.2282del4 display a pronounced phenotype, whereas in none of six individuals these two mutations were detectable despite decreased filaggrin expression on immunohistochemistry in two patients, indicating that other mutations in FLG and/or in other genes remain to be identified. In contrast, two additional p.R501X heterozygotes from the extended family are asymptomatic. In a control population from west-Austria a combined p.R501X and c.2282del4 carrier frequency of 6/110 (5.45%) was observed. We confirm that these FLG variants are common, but our results point to the existence of additional modifiers.

Epidermal differentiation complex yields a secret: mutations in the cornification protein filaggrin underlie ichthyosis vulgaris

Ichthyosis vulgaris (IV), characterized by mild scaling on limbs and lower abdomen, has an incidence of 1 in 250. Smith, McLean, and colleagues demonstrate that common mutations in filaggrin underlie IV. Filaggrin aggregates keratin intermediate filaments and is cross-linked into the cornified envelope to form the epidermal barrier. These findings reinforce the importance of the epidermal barrier in pathogenesis of skin diseases.

Mixed sclerosing dysplasia of the bone associated with ovarian and skin problems

The clinical, radiologic, histopathologic, and genetic features of a sclerosing bone dysplasia found in three members of a family are described. The bone disorder affected all metaphyseal-diaphyseal regions of all long bones, the skull, and three metacarpals. All affected members also had ichthyosis vulgaris and premature ovarian failure. These features have not been reported before, indicating a new syndrome.

Mapping of the associated phenotype of an absent granular layer in ichthyosis vulgaris to the epidermal differentiation complex on chromosome 1

Ichthyosis vulgaris (IV) is a mild to severe scaling disorder of uncertain etiology estimated to affect as many as 1 : 250 in the population. Family studies have shown that in many cases IV follows an autosomal dominant inheritance pattern, but gene mapping studies have not been reported. To investigate the genetic basis for inherited IV, we have performed gene linkage studies in two multigenerational families where affected individuals have clinical features of IV but distinct histological features. The epidermis in this disorder characteristically displays non-specific orthohyperkeratosis. Notably, a subset of IV patients with a reduced or absent granular epidermal layer (AGL) have been reported, and decreased filaggrin levels have been described in others. The prominent role of profilaggrin in human keratohyalin suggests that defects in the gene for profilaggrin (FLG), its processing of profillagrin to filaggrin, or a gene involved in profilaggrin regulation may underlie or modify the pathology in IV. Family 1 had seven individuals with IV, severe heat intolerance and epidermis with 1-3 granular layers (consistent with normal epidermal histology). Ichthyosis vulgaris in this family did not segregate with FLG or other genes in the epidermal differentiation complex. In contrast, five of the six IV patients in Family 2, all siblings, had epidermis with no granular layer. Significant evidence was obtained for linkage of IV with the associated AGL phenotype to the epidermal differentiation complex (which includes FLG) assuming either a recessive (max Lod 3.4) or dominant (max Lod 3.6) inheritance model. Sequence analysis of FLG did not reveal a mutation in the amino or carboxyl terminal portions of the coding sequence adjacent to filaggrin repeats. The AGL may represent an endophenotype for IV, and the presence of a modifier of IV pathology at this locus is discussed.

Expression of transglutaminase 5 in normal and pathologic human epidermis

To explore the expression and gain more information on the function of transglutaminase 5 enzyme in normal and defective human epidermis, we generated a rat antihuman transglutaminase 5 antiserum elicited against a purified active recombinant protein expressed in the baculovirus system. By use of Western blotting and immunofluorescence methods, the immunospecificity of the antibodies for transglutaminase 5 was tested; no crossreactivity with other transglutaminases (types 1, 2, and 3) was observed, thus allowing histochemistry studies. By indirect immunofluorescence analysis the antibodies decorated the upper layers of normal human epidermis, with consistent staining in the spinous and granular layers. We evaluated transglutaminase 5 expression in comparison with proliferating (keratin 14) and differentiating (transglutaminase 3) markers in different diseases, such as psoriasis, ichthyosis vulgaris, lamellar ichthyosis, and Darier's disease. We observed that transglutaminase 5 contributes, as a secondary effect, to the hyperkeratotic phenotype in ichthyosis (both vulgaris and lamellar) and in psoriasis. In Darier's disease, transglutaminase 5 expression, as well as transglutaminase 3, is completely missregulated, being overexpressed or totally absent in different areas of the same lesion.

Absence of the granular layer and keratohyalin define a morphologically distinct subset of individuals with ichthyosis vulgaris

The clinical diagnosis of ichthyosis vulgaris (IV) can be difficult. Abnormalities in the granular layer and the ultrastructure of keratohyalin granules (KHG) suggest that morphology may be helpful. To clarify morphologic findings in IV, 41 clinically affected individuals and 21 unaffected family members or age- and sex-matched controls were studied by light microscopy. In these, the granular layer was totally absent in approximately 50% of affected individuals, while present in all controls. Forty-seven individuals in the light microscopy group were also studied by electron microscopy. Keratohyalin granules were absent in all affected individuals lacking the granular layer by light microscopy. Clinical severity usually correlated with the lack of a granular layer and KHG. Absence of the granular layer was consistent in different anatomic sites and in serial biopsies taken over a 1-3-year period. In a subset of clinically affected, unrelated subjects with moderate to severe involvement, four out of 11 (36%) had similar findings. Keratinocytes cultured from affected individuals with no KHG expressed virtually no detectable profilaggrin protein in vitro. The data suggest that a subset of individuals with moderate to severe IV have a consistently absent granular layer and KHG. Absence of the granular layer and lack of KHG correlated almost perfectly; thus light microscopy offers a convenient means of identifying this subtype of IV. However, both morphologic types of IV were observed within single families. Therefore, the relationship between granular layer abnormalities and IV is complex and requires the study of more affected families. One interpretation of the data is that IV is a multigenic disorder in which one of the genes alters profilaggrin expression. We propose this clinical and histologic phenotype as useful for identifying the gene(s) involved and also for determining whether it represents a modifier or a major locus of the disorder.

New-onset ichthyosis and diabetes in a 14-year-old

Diabetes has not been linked to acquired ichthyosis or ichthyosis vulgaris. We report a newly diagnosed diabetic 14-year-old girl with bilateral tibial and sacral ichthyosiform plaques and a hemoglobin A1c of 20.1%. The patient had no personal or family history of atopy or ichthyosis and lacked keratosis pilaris or hyperlinear palms. A biopsy specimen of an ichthyosiform plaque showed compact lamellar orthohyperkeratosis and hypogranulosis, histopathology consistent with either ichthyosis vulgaris or acquired ichthyosis. We speculate that our patient's new-onset diabetes induced acquired ichthyosis.

Assessment of the clinical effect of topical tacalcitol on ichthyoses with retentive hyperkeratosis

BACKGROUND

Topical tacalcitol (1alpha,24-dihydroxyvitamin D3) has been demonstrated to produce beneficial clinical effects on epidermo-hyperproliferative disorders such as psoriasis and pityriasis rubra pilaris. However, the efficacy of the agent has not been elucidated in retentive hyperkeratotic disorders.

OBJECTIVE

The object of the study was to assess the clinical efficacy of topical tacalcitol against ichthyoses with retentive hyperkeratosis; X-linked ichthyosis (XLI), ichthyosis vulgaris (IV), and acquired ichthyosis (AI).

METHODS

Tacalcitol was topically applied on 9 patients with the retention ichthyoses, using a single-blinded, bilaterally paired approach with right-left comparison of tacalcitol and the base.

RESULTS

Clinical improvement obtained by topical tacalcitol exclusively was not superior to that of the vehicle alone in any of the ichthyotic patients.

CONCLUSION

Topical tacalcitol therapy was ineffective against ichthyoses without epidermal hyperproliferation.

KID syndrome associated with features of ichthyosis hystrix

Keratitis-ichthyosis-deafness (KID) syndrome is a congenital ectodermal disorder causing erythrokeratoderma, vascularizing keratitis, and neurosensory deafness. Ichthyosis hystrix is a rare cutaneous disease characterized by well-demarcated, spiky, verrucous, linear plaques that is believed to be a clinical and pathologic chimera of two autosomal dominant diseases: epidermal nevus and epidermolytic hyperkeratosis. We present a patient with the classic triad of KID syndrome with clinical and histologic features of ichthyosis hystrix. This case demonstrates that KID syndrome comprises a spectrum of ectodermal disorders which may include diseases such as hystrix ichthyosis and deafness (HID) syndrome.

Keratotsis punctata of the palmar creases: report of two cases associated with ichthyosis vulgaris

Two patients with keratosis punctata of the palmar creases are described. The association with ichthyosis vulgaris and other disorders of keratinization is discussed. In both cases, histopathology revealed a close relation between the keratotic plug and the sweat glands. The role of genetic factors and manual activity in the pathogenesis is discussed. Treatment with oral etretinate resulted in a good improvement in the first patient, but prolonged low-dose maintenance therapy was required to prevent recurrence.

Reduced stability and bi-allelic, coequal expression of profilaggrin mRNA in keratinocytes cultured from subjects with ichthyosis vulgaris

Ichthyosis vulgaris (IV) is an inherited scaling skin disorder in which expression of profilaggrin is reduced. Previous studies have indicated that the reduction is caused by defective post-transcriptional control of gene expression. Here we present evidence that profilaggrin mRNA in keratinocytes cultured from subjects with IV is intrinsically unstable and has a shorter half-life compared with that in normal cells. When IV-affected keratinocytes were treated with the protein synthesis inhibitor cycloheximide, the steady-state level of profilaggrin mRNA was increased due to stabilization of the transcript. In addition, the number of filaggrin repeats within the profilaggrin gene was studied. The number of filaggrin repeats (10-12) in individuals with IV did not differ from that of unaffected subjects. Expression of the gene was bi-allelic and coequal in both control and affected individuals. Our results suggest a model in which a labile ribonuclease and a stabilizing factor may modulate the profilaggrin mRNA steady-state level in normal cells, whereas the stabilizing factor may be absent or functionally inactive in IV-affected keratinocytes.

Disaggregation of corneocytes from surfactant-treated sheets of stratum corneum in hyperkeratosis on psoriasis, ichthyosis vulgaris and atopic dermatitis

To elucidate the pathogenesis of impaired barrier function and the influence of surfactant on the stratum corneum in hyperkeratosis, we investigated morphological alterations of the corneocytes with soap solution. Groups of five patients each with psoriasis vulgaris (PV), ichthyosis vulgaris (IV), atopic dermatitis (AD), and normal controls were examined. Four samples of the horny layer were obtained from the same site by cyanoacrylate adhesive biopsy. The first sample was used for the superficial layer, and the fourth, for the basal horny layers. Each sample was agitated in 1% stirred soap solution at 60 degrees C. The number and size of isolated corneocytes and the morphologic changes were investigated. The release of corneocytes was greater and the swelling and morphological changes of corneocytes exposed to soap solutions were less in PV and AD than in IV or in healthy subjects. In IV, the release was markedly less than in controls. The release and swelling were greater in the superficial than in the basal horny layers. It was concluded that the cohesiveness of corneocytes was probably less in PV and AD and greater in IV than in normals. It was also suggested that the cohesion of corneocytes from the superficial horny layer was less than that from the deep layer. The permeability of the cornified envelope in PV and AD patients was less than in IV or healthy subjects. It was confirmed that highly potent soaps induce loss of many corneocytes and reduce the barrier function of the stratum corneum.

[Ozena and allergic rhinitis in ichthyosis vulgaris]

The clinical course of an ozaena in a patient with an autosomal dominant ichthyosis vulgaris was complicated by the skin disease related atopic disposition with allergic rhinitis. Electron microscopic studies of the pathologically keratinized mucosa of the nasopharynx revealed a similar defect of the mucosal keratohyalin caused by the absence of the protein filaggrin.

Stereological studies of desmosomes in ichthyosis vulgaris

Standardized stereological methods were performed on biopsies from three subjects with normal skin and from three patients with autosomal dominant and three with autosomal recessive sex-linked ichthyosis to determine the relative numbers and dimensions of desmosomes. The results showed an increase in the persistence of desmosomes in the stratum corneum in both ichthyotic groups. This suggests a pathogenetic role for desmosomes in the abnormal desquamation of the two types of ichthyosis vulgaris.

Keratohyalin granules are heterogeneous in ridged and non-ridged human skin: evidence from anti-filaggrin immunogold labelling of normal skin and skin of autosomal dominant ichthyosis vulgaris patients

Recent biochemical and morphological investigations have provided evidence for a heterogeneous composition of keratohyalin in human skin. A major component is filaggrin. In interfollicular epidermis the heterogeneity of keratohyalin is not directly visible, whereas in normal ridged skin bicomponent keratohyalin is revealed by electron microscopy. Skin biopsies of ridged and non-ridged skin of normal individuals and patients with autosomal dominant ichthyosis vulgaris (ADI)--characterized by defective keratohyalin synthesis and lack of filaggrin--were investigated by routine transmission electron microscopy and immunogold postembedding techniques using a commercial monoclonal anti-filaggrin antibody. In normal interfollicular epidermis filaggrin labelling was demonstrated on keratohyalin granules and in the lowermost cornified cells, whereas in ADI patients crumbly keratohyalin granules were present that did not show specific labelling for filaggrin. In normal ridged skin only the major (more electron-dense) component reacted with anti-filaggrin, whereas the attached (less electron-dense) component did not react. Ridged skin of ADI patients contained globular keratohyalin that did not react with anti-filaggrin, thus corresponding to the attached keratohyalin component in normal ridged skin. Our results provide a visible counterpart to the recent biochemical investigations of keratohyalin protein heterogeneity and contribute to the understanding of terminal differentiation in human skin and of the defective keratohyalin synthesis in ADI.