Keratinocytes cultured from patients with Hailey-Hailey disease and Darier disease display distinct patterns of calcium regulation

BACKGROUND

Hailey-Hailey disease (HHD) (OMIM 16960) and Darier disease (DD) (OMIM 124200) are dominantly inherited acantholytic skin diseases, respectively, caused by mutations in the genes encoding the Golgi secretory pathway Ca2+-ATPase (SPCA1, ATP2C1) and the sarco/endoplasmic reticulum Ca2+-ATPase type 2 (SERCA2, ATP2A2) genes.

OBJECTIVES

To investigate calcium regulation in keratinocytes cultured from patients with HHD and DD by measuring intracellular calcium resting levels and the cellular responses to ATP and thapsigargin.

METHODS

The study was carried out using keratinocyte cultures established from four patients with HHD and four with DD. Calcium concentrations were measured with fluorescence ratio imaging using fura-2 loading.

RESULTS

Control and HHD keratinocytes displayed approximately the same Ca2+ levels in resting phase, while DD keratinocytes showed elevated Ca2+ levels. Application of ATP caused less pronounced elevation of intracellular calcium concentration ([Ca2+]i) in both HHD and DD keratinocytes than in control cells. HHD keratinocytes did not lower their [Ca2+]i as efficiently as control keratinocytes after treatment with thapsigargin. In addition, DD keratinocytes were practically incapable of lowering their [Ca2+]i after treatment with thapsigargin.

CONCLUSIONS

The results demonstrate that the defects in SPCA1 and SERCA2 calcium ATPases result in distinct patterns of calcium metabolism. This is also supported by the different clinical features of the diseases.

Discriminative Components of Data

A simple probabilistic model is introduced to generalize classical linear discriminant analysis (LDA) in finding components that are informative of or relevant for data classes. The components maximize the predictability of the class distribution which is asymptotically equivalent to 1) maximizing mutual information with the classes, and 2) finding principal components in the so-called learning or Fisher metrics. The Fisher metric measures only distances that are relevant to the classes, that is, distances that cause changes in the class distribution. The components have applications in data exploration, visualization, and dimensionality reduction. In empirical experiments, the method outperformed, in addition to more classical methods, a Renyi entropy-based alternative while having essentially equivalent computational cost.

Improved learning of Riemannian metrics for exploratory analysis

We have earlier introduced a principle for learning metrics, which shows how metric-based methods can be made to focus on discriminative properties of data. The main applications are in supervising unsupervised learning to model interesting variation in data, instead of modeling all variation as plain unsupervised learning does. The metrics are derived by approximations to an information-geometric formulation. In this paper, we review the theory, introduce better approximations to the distances, and show how to apply them in two different kinds of unsupervised methods: prototype-based and pairwise distance-based. The two examples are self-organizing maps and multidimensional scaling (Sammon's mapping).

Neurofibromatosis type 1 tumour suppressor gene expression is deficient in psoriatic skin in vivo and in vitro: a potential link to increased Ras activity

BACKGROUND

Neurofibromatosis type 1 (NF1) protein (neurofibromin) accelerates the inactivation of Ras-GTP in various cell types. Somatic mutations of the NF1 gene may lead to malignant transformation and uncontrolled proliferation. We have previously shown that NF1 protein expression is downregulated in psoriasis in vivo.

OBJECTIVES

To study the functional expression and distribution of NF1 mRNA and protein in vivo and in psoriatic and normal keratinocyte cultures.

METHODS

Immunohistochemistry and in situ hybridization were used to study NF1 gene and protein expression in psoriasis in vivo. Furthermore, Northern and in situ hybridizations, immunoblot and localization analyses were utilized to study NF1 mRNA and protein in vitro in keratinocyte cultures.

RESULTS

NF1 tumour suppressor gene expression was reduced in lesional psoriatic skin compared with perilesional and normal skin in vivo. The in vitro results showed that the levels of NF1 mRNA and protein were reduced in cultured psoriatic keratinocytes during cellular differentiation even after multiple passaging of the cells. Moreover, cultured nonlesional psoriatic keratinocytes were almost equally defective as lesional cells with respect to NF1 expression.

CONCLUSIONS

Our findings demonstrate that psoriatic keratinocytes maintain an altered phenotype and gene expression profile even when isolated from interaction with lymphocytes and fibroblasts, which are known to increase proliferation of keratinocytes. As NF1 protein is regarded as a Ras proto-oncogene regulator, the aberrant expression and distribution of NF1 protein and mRNA found in the present study may be causative to the previously described increased activation of Ras in psoriatic lesions, and relate to altered cellular behaviour.

Immunohistological distribution of the tight junction components ZO-1 and occludin in regenerating human epidermis

BACKGROUND

Molecular characterization of tight junction proteins during the past few years has provided novel methods for studying these specialized junctions. Tight junctions have recently been characterized in the granular cell layer of human epidermis, and the role of these junctions in the epidermal barrier is now being re-evaluated.

OBJECTIVES

To investigate the expression of tight junction components during the re-epithelialization of suction blisters and the regeneration of the corneal layer after tape stripping.

METHODS

Suction blisters were induced in eight healthy volunteers, and skin biopsies were taken 4 or 6 days afterwards. The restoration of epidermal barrier function was evaluated by measuring water evaporation (WE) from the wound area. Tape stripping was performed on three volunteers to remove the corneal layer. The tissues were immunolabelled using indirect immunofluorescence or the avidin-biotin method.

RESULTS

Prior to the biopsies, WE from the blister wounds was markedly elevated in comparison with normal skin. In the epidermis surrounding the blister, occludin and ZO-1 were expressed in the granular cell layer only. In the hyperproliferative zone adjacent to the border of the blister, the expression of ZO-1 was redistributed into several spinous cell layers, while occludin expression was restricted to the upper epidermis. In the leading edge of migrating keratinocytes, both proteins were expressed exclusively in the most superficial layer of keratinocytes. Double labelling for ZO-1 and involucrin showed expression of both proteins in the same layers of hyperproliferative keratinocytes, while the expression patterns were clearly different in the migrating keratinocytes.

CONCLUSIONS

Tight junctions of regenerating epidermis may provide a functional barrier prior to regeneration of the corneal layer.

Charcot arthropathy of the diabetic foot. Current concepts and review of 36 cases

BACKGROUND AND AIMS

The incidence of diabetic Charcot neuroarthropathy has increased. The purpose here was to study the current diagnostics and treatment of the Charcot foot.

MATERIALS AND METHODS

During a time period from 1994 to 2000, a total of 36 feet were diagnosed as cases of diabetic Charcot neuroarthropathies. A retrospective analysis of patient records and radiographs was undertaken. A review of the recent literature is presented.

RESULTS

29 cases were diagnosed in the dissolution stage, 2 in coalascence, and 5 in the resolution stage. The diagnostic delay averaged 29 weeks. Treatment with cast immobilisation ranged from 4 to 37 weeks (mean 11 weeks). A total of 14 surgical procedures were carried out on 10 patients: six exostectomies, four midfoot arthrodeses, one triple arthrodesis, one tibiocalcaneal arthrodesis and two below-knee amputations. A radiological fusion was achieved in two thirds of the attempted arthrodeses.

CONCLUSIONS

A physician should always consider the Charcot neuroarthropathy when a diabetic patient has an inflamed foot. In the absence of fever, elevated CRP or ESR, infection is a highly unlikely diagnosis, and a Charcot process should primarily be considered. The initial treatment of an inflamed Charcot foot consists in sufficiently long non-weightbearing with a cast, which should start immediately after the diagnosis. The prerequisites of successful reconstructive surgery are correct timing, adequate fixation and a long postoperative non-weightbearing period. In the resolution stage most Charcot foot patients need custom-molded footwear.

Effects of glucose on collagen mRNA levels and collagen secretion in EAhy 926 endothelial cell line

Diabetes mellitus (DM) is a complex metabolic disease associated with increased accumulation of extracellular matrix by endothelial cells and contributing to vascular complications of long-standing diabetes. On the other hand, DM is also associated with decreased accumulation of extracellular matrix in granulation tissue, which is suggested to be a consequence of impaired angiogenesis. The role of hyperglycemia in these situations is not fully understood. We examined the effects of high glucose concentrations on the gene expression and secretion of various collagens in cultured EAhy 926 endothelial cells. EAhy 926 endothelial cells expressed alpha1(I) collagen mRNA at a low level and small amount of the corresponding peptide was secreted from the cells; mRNA was not affected but peptide secretion was increased by elevated glucose concentration. mRNAs for type III and VI collagens were not detected in the endothelial cells. Furthermore, high glucose concentration in long term had no morphological effects on cultured endothelial cells but increased the expression of type IV collagen, which could rather be beneficial for angiogenesis in a healing wound. Our results suggest that high glucose concentration per se may contribute to increased accumulation of extracellular matrix in blood vessels but probably is not responsible for decreased angiogenesis and granulation tissue formation in diabetic patients.

The effects of sialic acid on the gene expression of fibrillar collagens: different changes in normal and fibrotic scar derived fibroblasts

OBJECTIVE

To investigate the effect of free sialic acid on collagen gene expression in fibroblasts.

DESIGN

Cell culture study.

SETTING

University hospital, Finland. CELL LINES: Human granulation tissue fibroblasts, human hypertrophic scar fibroblasts and human keloid fibroblasts.

INTERVENTIONS

Treatment of cell cultures with 3 microM, 30 microM and 300 microM N-acetyl-neuraminic acid.

MAIN OUTCOME MEASURES

The measurement of steady state level of mRNA for type I and type III collagen.

RESULTS

Fibroblast lines react dissimilarly under the influence of sialic acid. Granulation tissue fibroblasts showed decrease in the gene expression of type I and III collagen, while keloid fibroblasts contrastingly showed an increase. Hypertrophic scar derived fibroblasts showed no change.

CONCLUSIONS

Sialic acids may decrease collagen gene expression in granulation tissue and that disturbed wound healing in diabetics and smokers may in part be due to direct effect of sialic acids on fibroblasts. Sialic acids may in part induce keloid formation.

The effects of sialic acid on the gene expression of fibrillar collagens: different changes in normal and fibrotic scar derived fibroblasts

OBJECTIVE

To investigate the effect of free sialic acid on collagen gene expression in fibroblasts.

DESIGN

Cell culture study.

SETTING

University hospital, Finland. CELL LINES: Human granulation tissue fibroblasts, human hypertrophic scar fibroblasts and human keloid fibroblasts.

INTERVENTIONS

Treatment of cell cultures with 3 microM, 30 microM and 300 microM N-acetyl-neuraminic acid.

MAIN OUTCOME MEASURES

The measurement of steady state level of mRNA for type I and type III collagen.

RESULTS

Fibroblast lines react dissimilarly under the influence of sialic acid. Granulation tissue fibroblasts showed decrease in the gene expression of type I and III collagen, while keloid fibroblasts contrastingly showed an increase. Hypertrophic scar derived fibroblasts showed no change.

CONCLUSIONS

Sialic acids may decrease collagen gene expression in granulation tissue and that disturbed wound healing in diabetics and smokers may in part be due to direct effect of sialic acids on fibroblasts. Sialic acids may in part induce keloid formation.

Effects of glucose on collagen mRNA levels and collagen secretion in EAhy 926 endothelial cell line

Diabetes mellitus (DM) is a complex metabolic disease associated with increased accumulation of extracellular matrix by endothelial cells and contributing to vascular complications of long-standing diabetes. On the other hand, DM is also associated with decreased accumulation of extracellular matrix in granulation tissue, which is suggested to be a consequence of impaired angiogenesis. The role of hyperglycemia in these situations is not fully understood. We examined the effects of high glucose concentrations on the gene expression and secretion of various collagens in cultured EAhy 926 endothelial cells. EAhy 926 endothelial cells expressed alpha 1(I) collagen mRNA at a low level and small amount of the corresponding peptide was secreted from the cells; mRNA was not affected but peptide secretion was increased by elevated glucose concentration. mRNAs for type III and VI collagens were not detected in the endothelial cells Furthermore, high glucose concentration in long term had no morphological effects on cultured endothelial cells but increased the expression of type IV collagen, which could rather be beneficial for angiogenesis in a healing wound. Our results suggest that high glucose concentration per se may contribute to increased accumulation of extracellular matrix in blood vessels but probably is not responsible for decreased angiogenesis and granulation tissue formation in diabetic patients.

Stability of leisure-time physical activity during adolescence--a longitudinal study among 16-, 17- and 18-year-old Finnish youth

Participation in physical activity during childhood and adolescence is frequently mentioned as one factor likely to promote a more active lifestyle in adulthood with its health benefits. We studied the changes in leisure-time physical activity pattern and self-reported fitness during a three-year period in adolescence and investigated whether the type of sports has an effect on stability of physical activity at leisure. A questionnaire with identical physical activity items was sent to Finnish twins on their 16th and 17th birthdays and 6 months after the 18th birthday. A total of 1338 boys and 1596 girls responded to all three questionnaires, with response rates of 73.6% and 86.5%. The proportions of very active adolescents and adolescents with very good self-reported fitness seem to be alike at each age. Among girls, 23.7% to 27.7% reported being very active (4-5 times a week) and 13.7% to 15.1% considered their physical fitness to be very good at the ages of 16, 17 and 18. Among boys, the comparable percentages were 31.5% to 35.5% and 30.6% to 34.4%. However, the longitudinal three-year follow up showed substantial changes over time among individuals from one physical activity group to another. Only 19.1% of boys and 11.2% of girls were persistent exercisers (i.e., very active on all three years) and 15.6% of boys and 5.1% of girls were persistently fit (i.e., very good self-reported fitness on all three years). Stability of leisure-time physical activity was highest among those who participated in several different types of sports. Among boys the proportion of persistent exercisers was highest for those who participated in cross-country skiing, jogging and body-building (22.0-41.5%) and among girls for those who participated in ball games (11.9-28.6%). Those who participated in organised sports were more often persistent exercisers than those who did not (odds ratio = 13.2 for boys (CI 9.4-18.7) and 8.9 for girls (CI 6.4-12.5)). Also, those who participated in organised sports were more often persistently fit (odds ratio = 7.3 for boys (CI 5.2-10.2) and 10.4 for girls (CI 6.4-16.9). Adolescents are recommended to participate in and try different types of sports, and especially for girls ball games would appear to favour long-term maintenance of leisure-time physical activity.

Epidermal tight junctions: ZO-1 and occludin are expressed in mature, developing, and affected skin and in vitro differentiating keratinocytes

This study demonstrates the presence of tight junction antigens in adult and developing human epidermis. Indirect immunofluorescence labeling and immunoelectron microscopy with antibodies to ZO-1 and occludin localized tight junction components ZO-1 and occludin to a narrow zone of the granular cells of adult epidermis. Double immunolabeling for tight junction components with adherens junction or desmosome proteins suggested that occludin is more specific for tight junctions than ZO-1, which may also be associated with adherens junctions. In developing skin, tight junctions interconnected the peridermal cells, and after the fetal stratification localized to the granular cell layer. Immunolabeling of psoriasis, lichen planus, and ichthyosis vulgaris, representing aberrant differentiation of the epidermis, showed that these conditions were associated with relocation of ZO-1 and occludin to the spinous cells. Cultures of epidermal keratinocytes, which offer a useful model for the formation of cellular contacts, revealed that tight junction components, ZO-1 and occludin, displayed a marked degree of colocalization relatively late during the process when the fusion zone had assumed a linear appearance. This suggests that the formation of adherens junctions and desmosomes precedes that of tight junctions. We speculate that the epidermal barrier, isolating the human body from the external environment, is in part formed by tight junctions of stratum granulosum.

Scoliosis in patients with diastrophic dysplasia: a new classification

STUDY DESIGN

Scoliosis in patients with diastrophic dysplasia was analyzed.

OBJECTIVES

To study the natural history of scoliosis and to classify the patients with different types of scoliosis.

SUMMARY OF BACKGROUND DATA

Typical findings in diastrophic dysplasia are short-limbed short stature, multiple joint contractures, early degeneration of joints, and spinal deformities. The largest studies have reported scoliosis in 37% to 88% of the patients with this rare skeletal dysplasia. The natural history of the deformity is unknown.

METHODS

Of the 130 unselected patients, 98 (75%) who were older than 16 years and/or had undergone surgery at the time of the last radiograph were included in the final analysis. These 98 patients included 37 males and 61 females. Their ages at the first radiograph ranged from newborn to 78 years (average, 21 years). The mean follow-up period was 20 years (range, 2-41 years) for 80 patients. Standard standing anteroposterior and lateral radiographs were taken. The degrees of scoliosis, kyphosis, and lordosis were measured according to the Cobb method. Classification of the scoliosis was based on the patient's age at onset of scoliosis, the rate of progression, the magnitude of the scoliosis at the end of growth, and the curve pattern.

RESULTS

Of the 98 patients in this study, 86 (88%) had scoliosis. This difference was highly significant statistically (P < 0.001), as compared with the normal population. The frequency of scoliosis was 90% among females and 84% among males. Scoliosis can be divided further into three subtypes: early progressive (11 patients), idiopathic-like (41 patients), and mild nonprogressive (33 patients). One patient had a congenital scoliosis.

CONCLUSIONS

Scoliosis is very common in patients with diastrophic dysplasia. The natural history of scoliosis varies from severe deformity with rapid progression to mild deformity without any progression. The authors suggest that the classification described in this report offers a tool for the predicting natural history of scoliosis in diastrophic dysplasia, and for adjusting the timing of surgery in individual patients.

Expression profiles of cell-cell and cell-matrix junction proteins in developing human epidermis

The spatial distribution of a panel of cell junction proteins was studied in developing human epidermis by confocal laser scanning microscopy. The results demonstrated that many of the cell junction proteins were expressed in early two-layered embryonic epidermis, but their subcellular distribution displayed marked changes during development. Specifically, desmosomal proteins, desmoplakin, desmocollin and desmoglein, adherens junction components, E-cadherin, alpha-catenin and vinculin, and an actin-binding protein alpha-actinin were expressed as early as 8 weeks of estimated gestational age (EGA). Type IV collagen and beta1 and beta4 integrins were also present. At this early developmental stage, the epidermis is known to comprise two layers of cells, the basal layer and the peridermal layer. In addition to being present in cell-cell contacts, desmosomal antigens and E-cadherin were unexpectedly localized to the basal aspect of basal cells in samples at 8 weeks. On the other hand, talin, which in adult skin is localized to the dermal-epidermal junction, could not be detected until 12 weeks. These results suggest that the separation of cell membranes to the basal and apicolateral compartments does not occur before the maturation of the basement membrane zone. At 8 weeks EGA, gap junction antigen connexin 43 was expressed in scarce spots in cell-cell contacts of basal cells. In samples of 11-21 weeks EGA, the density of desmosomal and adherens junction markers as well as connexin 43 increased in cell-cell junctions, together with the appearance of the intermediate cell layer and beginning of stratification of the epidermis.

Differential effects of hexoses and sucrose, and platelet-derived growth factor isoforms on cyclooxygenase-1 and -2 mRNA expression in keloid, hypertrophic scar and granulation tissue fibroblasts

Cyclooxygenase (COX) is the key enzyme in the formation of prostaglandins in inflammation. In the present study the effects of biomedically relevant hexose sugars (glucose, fructose, galactose, mannose) and sucrose disaccharide on the expression of COX-1 and COX-2 genes were evaluated in granulation tissue fibroblasts, hypertrophic scar fibroblasts and keloid fibroblasts. The effects of three isoforms (AA, AB and BB) of PDGF on COX gene expression in granulation tissue fibroblasts were also examined. All cell lines expressed COX-1 mRNA, whilst fibroblasts derived from abnormal scars did not express COX-2 mRNA. COX-1 mRNA expression was decreased by sugars in granulation tissue fibroblasts and increased in hypertrophic scar fibroblasts. No major changes were seen in keloid fibroblasts. On the other hand, COX-2 mRNA expression in granulation tissue fibroblasts was decreased dramatically in the presence of fructose, mannose and sucrose and moderately in the presence of galactose. All isoforms of PDGF increased COX-1 and COX-2 mRNA expression in granulation tissue fibroblasts, the most marked increases being elicited by PDGF-BB. All fibroblast cell lines studied expressed the COX-1 gene while the COX-2 gene was not expressed by abnormal scar-derived fibroblasts. Further, granulation tissue fibroblasts seemed to behave differently under the influence of sugars compared to hypertrophic scar fibroblasts whilst keloid fibroblasts seemed to be relatively unaffected by sugars. In addition, the PDGF-BB isoform is a potent inducer of COX-2 gene expression in wound fibroblasts. These findings may be relevant to the development of abnormal scars and indicate the need for further studies.