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Biomedical subjects

K De Paepe

Publications and source records attributed to K De Paepe.

12 recordsLinked to original sources
PubMed2006

A keratinocyte's course of life.

An adequate permeability barrier function of the mammalian epidermis is guaranteed by the characteristic architecture of the stratum corneum. This uppermost layer consists of a highly organized extracellular lipid compartment which is tightly joined to the corneocytes. The generation of the extracellular lipid compartment and the transformation of the keratinocytes into corneocytes are the main features of epidermal differentiation. However, equally important is the continuous renewal of the stratum corneum, which is insured by a careful balance between the replenishment of new keratinocytes from the proliferating basal layer, and the well-orchestrated loss of the most superficial cells after the so-called 'epidermal programmed cell death'. In this overview, the complete life of keratinocytes is described, from the proliferative organization to the process of desquamation.

Animals↗
PubMed2005

Effect of oral intake of choline-stabilized orthosilicic acid on skin, nails and hair in women with photodamaged skin.

Chronic exposure of the skin to sunlight causes damage to the underlying connective tissue with a loss of elasticity and firmness. Silicon (Si) was suggested to have an important function in the formation and maintenance of connective tissue. Choline-stabilized orthosilicic acid ("ch-OSA") is a bioavailable form of silicon which was found to increase the hydroxyproline concentration in the dermis of animals. The effect of ch-OSA on skin, nails and hair was investigated in a randomized, double blind, placebo-controlled study. Fifty women with photodamaged facial skin were administered orally during 20 weeks, 10 mg Si/day in the form of ch-OSA pellets (n=25) or a placebo (n=25). Noninvasive methods were used to evaluate skin microrelief (forearm), hydration (forearm) and mechanical anisotropy (forehead). Volunteers evaluated on a virtual analog scale (VAS, "none=0, severe=3") brittleness of hair and nails. The serum Si concentration was significantly higher after a 20-week supplementation in subjects with ch-OSA compared to the placebo group. Skin roughness parameters increased in the placebo group (Rt:+8%; Rm: +11%; Rz: +6%) but decreased in the ch-OSA group (Rt: -16%; Rm: -19%; Rz: -8%). The change in roughness from baseline was significantly different between ch-OSA and placebo groups for Rt and Rm. The difference in longitudinal and lateral shear propagation time increased after 20 weeks in the placebo group but decreased in the ch-OSA group suggesting improvement in isotropy of the skin. VAS scores for nail and hair brittleness were significantly lower after 20 weeks in the ch-OSA group compared to baseline scores. Oral intake of ch-OSA during the 20 weeks results in a significant positive effect on skin surface and skin mechanical properties, and on brittleness of hair and nails.

Administration, Oral↗
PubMed2002

Efficacy of topical corticosteroids in nickel-induced contact allergy.

In this study we used the nickel contact allergy patch (CAP) test to investigate the effect of topical corticosteroids on allergic contact dermatitis (ACD). On day 1, three CAP tests were applied for 48 h on the forearms of 20 female volunteers with a known nickel ACD. CAP of the right forearm contained 5% nickel, and of the left forearm physiological saline. Clinical scoring, transepidermal water loss and skin hydration were measured on day 1 before CAP application, on day 4 (0, 2 and 6 h) after ACD and from days 5 to 8 (0 h). A topical corticosteroid and its vehicle were applied twice daily starting from day 4 on two ACD sites. Transepidermal water loss values were significantly decreased on the topical-corticosteroid-treated sites in the early phase of ACD (day 4, 6 h after the first application) while clinical efficacy showed significant improvement on days 7 and 8. The vehicle was found to improve skin hydration only on day 8. In conclusion the topical corticosteroid improved the skin barrier function in the early inflammatory phase of ACD (day 4, 6 h). The lack of improvement in transepidermal water loss in the later phase of ACD might be accounted for by the secondary effects of the corticosteroid on proliferation and differentiation of keratinocytes.

Administration, Cutaneous↗
PubMed2002

Repair of acetone- and sodium lauryl sulphate-damaged human skin barrier function using topically applied emulsions containing barrier lipids.

BACKGROUND: It is generally acknowledged that well-formulated moisturizing skin care products can restore disturbed barrier function that can be assessed by transepidermal water loss (TEWL) measurements. When ceramides and/or other barrier lipids are incorporated, it is, however, not always clearly demonstrated which ingredients of the formulation exert the beneficial effects. OBJECTIVES: In this study the effects of topically applied ceramide-containing mixtures on the barrier repair of sodium lauryl sulphate (SLS)- and acetone-induced skin damage have been studied in human volunteers. TEWL and stratum corneum hydration measurements were carried out. The emulsions applied contained either a mixture of two types of ceramides, CerIII and CerIIIB (emulsion 1) or a complete mixture of ceramides III, IIIB and VI together with phytosphingosine, cholesterol and the free fatty acid linoleic acid (emulsion 2). RESULTS: After SLS damage, it was observed that barrier recovery was significantly accelerated by topical application (14 days, 2 x/d) of emulsion 2 compared with the results obtained with emulsion 1. Corneometrical results were not relevant due to the occurrence of scaly fissured skin, failing to provide a good skin/probe contact. Although no effect on TEWL could be observed, the improvement of skin hydration after acetone treatment and a single application of the emulsions, was significantly more positive for emulsion 2 than for emulsion 1. CONCLUSIONS: The investigative methods used in this study show that ceramides combined with other skin lipids can improve barrier repair after damage.

Acetone↗
PubMed2002

Resistance versus endurance training in patients with COPD and peripheral muscle weakness.

The effects of endurance training on exercise capacity and health-related quality of life (HRQL) in chronic obstructive pulmonary disease (COPD) patients have been studied thoroughly, while resistance training has been rarely evaluated. This study investigated the effects of resistance training in comparison with endurance training in patients with moderate to severe COPD and peripheral muscle weakness (isometric knee extension peak torque <75% predicted). Forty-eight patients (age 64+/-8 yrs, forced expiratory volume in one second 38+/-17% pred) were randomly assigned to resistance training (RT, n=24) or endurance training (ET, n=24). The former consisted of dynamic strengthening exercises. The latter consisted of walking, cycling and arm cranking. Respiratory and peripheral muscle force, exercise capacity, and HRQL were re-evaluated in all patients who completed the 12-week rehabilitation (RT n=14, ET n=16). Statistically significant increases in knee extension peak torque (RT 20+/-21%, ET 42+/-21%), maximal knee flexion force (RT 31+/-39%, ET 28+/-37%), elbow flexion force (RT 24+/-19%, ET 33+/-25%), 6-min walking distance (6MWD) (RT 79+/-74 m, ET 95+/-57 m), maximum workload (RT 15+/-16 Watt, ET 14+/-13 Watt) and HRQL (RT 16+/-25 points, ET 16+/-15 points) were observed. No significant differences in changes in HRQL and 6MWD were seen between the two treatments. Resistance training and endurance training have similar effects on peripheral muscle force, exercise capacity and health-related quality of life in chronic obstructive pulmonary disease patients with peripheral muscle weakness.

Aged↗
PubMed2001

Squamometry as a screening method for the evaluation of hydrating products.

BACKGROUND/AIMS: Squamometry is a combination of sampling corneocytes by adhesive coated discs followed by colour measurements after staining the cells. In this study, the correlation between stratum corneum (SC) hydration and scaling was investigated using capacitance measurements and squamometry, respectively. METHODS: Stratum corneum hydration and assessment of barrier function by transepidermal water loss (TEWL) measurements were carried out on different sites of left and right volar forearm skin of female volunteers (n = 13; 24 +/- 3 years). D-Squame samples were taken on the same test spots. RESULTS: Visual evaluation of the coloured samples by light microscopy and the development of a four-point-scale scoring system was found to be necessary to detect and minimise overestimation of chroma C* values. Capacitance measurements revealed neither significant differences between corresponding sites on left and right forearms no between different skin areas on the same forearm. Squamometric measurements, on the contrary, did not show any symmetry between corresponding test sites on both forearms or between different sites on one forearm. No correlation could be found between squamometric measurements and SC hydration values obtained at the same test sites. No skin barrier function impairment lays at the origin of this observation since TEWL values were found to be similar at all test sites in comparison to control skin. In a randomised single blind study, hydration and TEWL showed a significant improvement of 25% and 15%, respectively, after a 14-day application period of a moisturising cream. Although visual scoring of the coloured samples of both treated and untreated test spots revealed a good correlation with chroma C* values, the quantitative results found with squamometry were very doubtful. CONCLUSION: Squamometry with visual scoring can be proposed as a screening technique for SC hydration rather than a quantitative method to appreciate skin moisturisation.

Administration, Cutaneous↗
PubMed2001

Combination therapy improves the recovery of the skin barrier function: an experimental model using a contact allergy patch test combined with TEWL measurements.

BACKGROUND: Nickel (Ni) allergic contact dermatitis (ACD) alters the skin barrier. OBJECTIVE: Our aim was to compare the efficacy of combination therapies on ACD, using a topical corticosteroid and a corneotherapy agent (barrier cream), with that of a single therapy with corticosteroids. METHODS: On day 1, 3 Ni test patches were applied on each forearm of 14 Ni-patch-test-positive females. Four contained 5% Ni and 2 physiological saline. Either topical corticosteroid or barrier cream were matched with the combination of both products on 3 of the 4 Ni ACD. The fourth was not treated. Clinical scoring, transepidermal water loss (TEWL) and stratum corneum (SC) capacitance were measured before (day 1) and after (days 4-8) ACD. RESULTS: The combination therapy showed a significant decrease in TEWL values and an increase in SC capacitance. CONCLUSION: Combining a topical corticosteroid with corneotherapy agents prevents the delay in the healing process of skin barrier disruption due to ACD.

Administration, Cutaneous↗
PubMed2001

Reduced epithelial expression of secretory component in small airways correlates with airflow obstruction in chronic obstructive pulmonary disease.

The epithelial polymeric immunoglobulin receptor/transmembrane secretory component (pIgR/SC) transports into secretions polymeric immunoglobulin A (pIgA), which is considered the first line of defense of the respiratory tract. The present study, done with quantitative immunohistochemistry, evaluated epithelial expression of secretory component (SC) and Clara cell protein (CC16) and neutrophil infiltration into the airways of eight patients with severe chronic obstructive pulmonary disease (COPD) who were undergoing lung transplantation, as compared with these processes in six nonsmoking patients with pulmonary hypertension who were used as controls and in lung specimens from five smokers without chronic bronchitis. Staining for SC was significantly decreased in the COPD patients as compared with the controls, both in large (mean optical density [MOD]: 23.4 [range: 21.1 to 27.8] versus 42.2 [range: 28.2 to 49.3], p = 0.003) and in small airways (MOD: 30.8 [range: 20.3 to 39.4] versus 41.5 [range: 39.2 to 46.2], p = 0.003). SC expression in small airways correlated strongly with functional parameters such as FEV1 (Kendall's tau (K) = 0.76, p = 0.008), FVC (K = 0.64, p = 0.03), and midexpiratory flow at 50% of VC (MEF50) (K = 0.74, p = 0.01). The reduced expression of SC in large airways correlated with neutrophil infiltration in submucosal glands (K = -0.47, p = 0.03). Expression of CC16 in the bronchial epithelium of COPD patients was also significantly decreased as compared with that of controls, especially in small airways (MOD: 28.3 [range: 26.8 to 32.4] versus 45.8 [range: 40.7 to 56.0], p = 0.002), but no correlation was observed with lung function tests. In conclusion, this study shows that reduced expression of SC in airway epithelium is associated with airflow obstruction and neutrophil infiltration in severe COPD.

Adolescent↗
PubMed2000

Microrelief of the skin using a light transmission method.

The recently developed Skin Visiometer, based on light transmission through blue-coloured silicone replicas, was used to study skin microrelief. Calibrated metal plates displaying lines with depths between 6 and 361 microns, were used to determine the accuracy, sensitivity and reproducibility of the technique as well as the parameters of importance during measurement. The precision of the measurements was particularly good between 10 microns and 361 microns. The sensitivity of the method was between 10 and 20 microns. Replicas of volar forearm skin were taken from four groups (n = 15) of male and female volunteers in the age ranges 20 to 30 years and 55 to 65 years. In addition to the instrumental roughness parameters (Rz, Rt, Rm and Ra), the surface of the furrows, the number of primary and secondary lines and the number of intersections were determined. For both sexes, significantly lower values were observed for Rz, Rm and Rt in the younger age group than in the older age group. In addition, the numbers of primary and secondary lines and the number of intersections were higher, pointing to a more structured microrelief in younger forearm skin. Diurnal rhythm, the relative humidity of the measuring room and the position of the forearm were found to be significant factors, while room temperature and precleansing of the skin with mild products were not. Following the application of a hydrating cream (twice daily for 14 days) to the forearm skin of the older female age group, the Rz, Rt, Rm and Ra decreased, while the other parameters measured, except for the surface taken in by the lines, increased, indicating that the microrelief was modified towards the typical pattern observed in young skin.

Adult↗
PubMed2000

Incorporation of ceramide 3B in dermatocosmetic emulsions: effect on the transepidermal water loss of sodium lauryl sulphate-damaged skin.

BACKGROUND: In previous work we reported on the efficacy of cosmetic body lotions enriched with skin-identical lipids to reduce the transepidermal water loss (TEWL) of ageing and sodium lauryl sulphate (SLS)-damaged skin. The observations made depended on the experimental design and clearly raised the question of the importance of the galenic formulation of skin ceramide-containing products. OBJECTIVES: The aim of the present work was to study the different galenic forms in which ceramide 3B (0.2% w/v) can be incorporated into common o/w emulsions. In addition, we investigated whether supplementation of skin care products with ceramide 3B enriched with penetration enhancers and coemulsifiers could exert a beneficial effect on barrier function, done by measuring their effects on the TEWL of SLS-induced scaly skin. RESULTS: We found that the technique of incorporating ceramide 3B into the o/w emulsions was important for their final stability. However, no additional positive effect on the TEWL values of SLS-damaged skin could be observed when the efficacy of the ceramide-containing emulsions was compared with that of proper controls. CONCLUSIONS: Although suitable galenic formulas were developed, no positive effect on TEWL could be observed when ceramide 3B was added in a final concentration of 0.2% (w/v) to different o/w emulsions and applied to SLS-damaged skin.

Adult↗
PubMedDate not supplied

Analysis of epidermal lipids of the healthy human skin: factors affecting the design of a control population.

The intervariability of studies on the lipids of human epidermis and stratum corneum is high because of the different origin of the skin samples and the variety of extraction methods used. In the present work, a high-performance thin-layer chromatographic technique has been used to study the parameters age, sex, and anatomical site for their effects on the lipid profiles recovered from healthy epidermal skin biopsy specimens. It was found that sex-related differences were seen at the level of the total ceramide concentration. Observed decreases in lipid concentration, due to ageing, depended on the anatomical site. Therefore, these variables should be controlled in a reproducible and standardized way in order to be able to study the direct relationship between skin condition and barrier lipid composition. Only when this relation is established, results of topical treatment can be scientifically evaluated.

Adult↗