Transonychial Water Loss Research Articles

Transepidermal water loss (TEWL) and transonychial water loss (TOWL) measurements in healthy nail apparatus.

Although non-invasive diagnostic methods are widely used to examine the nail apparatus (NA), studies in healthy ones are scarce, and analyzes were often conducted in small groups. In the literature, there are only a few reports on TOWL measurements. The results of TEWL studies in the proximal nailfold have not been published so far. Based on a detailed interview and physical examination, 81 volunteers (40 women and 41 men) aged from 22 to 65 years were qualified for the study. In this study, the overall examination of the NA in relation to water loss was performed for the first time, regarding the hand (d, dominant; n, non-dominant) and finger types (number, start of count from thumbs) as well as sex and age. The average TEWL value in the entire group ranged from 7.53 c.u. in the finger nd4 to 11.09 c.u. in nd1. Both in the dominant and non-dominant hand, in the entire analyzed group, and taking into account gender, weak statistically significant relationships were observed between the finger type value and TEWL (p<0.05).The TEWL values were lower moving away from the thumb, The average TOWL value in the entire group ranged from 5.01 c.u. in d1 to 7.34 c.u. in d5. Both in the dominant and non-dominant hand, in the entire analyzed group and considering gender, statistically significant relationships were observed between the type of finger and TOWL values (p<0.05). The TOWL values were higher moving away from the thumb. Subsequently, the values of TOWL and TEWL did not depend on type of hand (dominant or non-dominant), sex and age. Weak and moderate statistically significant correlations were found between TEWL and TOWL values in the entire study group and in females, as well as in selected fingers in males (d2, nd2, d3, nd3, d5, nd5) (p<0.05, r<0.27). Non-invasive diagnostics such TEWL and TOWL measurements are useful to assess differences in structure and function between types of fingers. However, obtained results demand further studies.

Pilot Study of the Efficacy and Safety of Nail Gel Containing Artemisia abrotanum Extract and Glycerin in the Treatment of Nail Plate Surface Abnormality

Background: Nail gels are utilized for the treatment of nails for nail plate surface abnormalities. However, the objective measurement of nail gel treatment is limited.&#x0D; Objective: This study investigated the efficacy and safety of a nail gel containing glycerin and Artemisia abrotanum extract in treating nail plate surface abnormalities.&#x0D; Material and Methods: All nails were evaluated with a Visiometer® system and by transonychial water loss (TOWL) at baseline, and at the 2nd and 8th weeks of treatment.&#x0D; Results: In total, 19 patients with a mean age of 50.6 years old were enrolled and 50 nails were studied. Sixty percent of the patients showed significant clinical improvement, as determined by the total agreement between two treatment-blinded dermatologists. Regarding the Visiometer®, a significant reduction in the SER value (roughness) of the nail plates was found at the 2nd week, while at the 8th week, the surface and volume values had significantly decreased from baseline and also from the values at the 2nd week. There was a significant improvement in the Rku (smoothness) value at the 8th week compared to baseline. The mean TOWL at the 2nd and 8th weeks were statistically decreased from baseline. No side effects were detected.&#x0D; Conclusions: This nail gel containing Artemisia abrotanum extract provided benefits in restoring hydration and improving the nail barrier in patients with nail surface abnormalities.

A novel technique to evaluate nail softening effects of different urea formulations

Urea has been incorporated into several topical ungual formulations to hydrate and soften the nail plate. In this study, we employed various characterization techniques (visual observation, scanning electron microscopy, measurement of thickness, transonychial water loss, nail electrical resistance, and mechanical study) to investigate the effect of urea concentration on the hydration of bovine hoof membranes – an in vitro model of infected human nails. We obtained inconsistent results in the thickness, transonychial water loss, nail electrical resistance, and scanning electron microscopy studies. In the mechanical study using a modified Texture Analyzer method, we reported an inverse and linear correlation between urea concentrations in the formulations and the force required to puncture the treated membrane (R 2 = 0.9582, n ≥ 8). As the urea concentration decreased from 4x to 2x, 1x, and 0x % w/w, the puncture force increased significantly from 0.47 ± 0.07 to 0.77 ± 0.07, 0.91 ± 0.09, and 1.33 ± 0.26 N, respectively (p < 0.05). Thus, urea provided a positive softening effect on the membranes and the puncture force could indicate the urea level in topical formulations. In this study, we provided a novel, efficient, and reliable tool to evaluate the hydration level and physical properties of bovine hoof membranes.

An investigation of how fungal infection influences drug penetration through onychomycosis patient’s nail plates

The treatment of onychomycosis remains problematic even though there are several potent antifungal agents available for patient use. The aim of this investigation was to understand whether the structural modifications that arise when a patient’s nail become infected plates influences the permeation of drugs into the nail following topical application. It was hoped that through improving understanding of the nail barrier in the diseased state, the development of more effective topical treatments for onychomycosis could be facilitated. The permeation of three compounds with differing hydrophobicities, caffeine, terbinafine and amorolfine (clogD at pH 7.4 of −0.55, 3.72 and 4.49 respectively), was assessed across both healthy and onychomycosis infected, full thickness, human nail plate sections. Transonychial water loss (TOWL) measurements performed on the healthy and diseased nails supported previous observations that the nail behaves like a porous barrier given the lack of correlation between TOWL values with the thicker, diseased nails. The flux of the more hydrophilic caffeine was twofold greater across diseased in comparison with the healthy nails, whilst the hydrophobic molecules terbinafine and amorolfine showed no statistically significant change in their nail penetration rates. Caffeine flux across the nail was found to correlate with the TOWL measurements, though no correlation existed for the more hydrophobic drugs. These data supported the notion that the nail pores, opened up by the infection, facilitated the passage of hydrophilic molecules, whilst the keratin binding of hydrophobic molecules meant that their transport through the nail plate was unchanged. Therefore, in order to exploit the structural changes induced by nail fungal infection it would be beneficial to develop a small molecular weight, hydrophilic antifungal agent, which exhibits low levels of keratin binding.

The correlation between transonychial water loss and Nail Psoriasis Severity Index in nail psoriasis

The correlation between transonychial water loss and Nail Psoriasis Severity Index in nail psoriasis

Confocal laser scanning microscopy, optical coherence tomography and transonychial water loss for in vivo investigation of nails

Nail disorders can be diagnostically challenging to the dermatologist. Noninvasive methods might help to avoid nail biopsies. More knowledge of the typical features of healthy nails with these techniques is needed for comparison with nail diseases. To describe the typical morphology of healthy nails in optical coherence tomography (OCT) and confocal laser scanning microscopy (CLSM) and to examine the influence of exposure to water on OCT features, nail thickness as well as on transonychial water loss (TOWL) before and after a hand bath. Material and methods In the first part healthy nail plates were investigated with OCT and CLSM. The thickness of layers as well as structural details were defined. Secondly, in a prospective study 30 healthy volunteers conducted 10 hand baths with water within a 2-week period. Measurements of nail thickness and signal intensity by OCT as well as of the TOWL were performed over time. In OCT the unaffected nail plate appears as a band-like, layered structure, yet with some individual differences. In addition, CLSM is able to display single corneocytes and the integrity of their borders. Exposure to water led to a transient rise of TOWL and in nail thickness. OCT, CLSM and TOWL offer valuable noninvasive diagnostic tools for the examination of nails. Using CLSM, microscopic features like integrity of single corneocytes can be investigated. OCT allows determination of nail plate thickness and both OCT and TOWL measurements are able to detect short-term effects after exposure to water.

Opto-thermal radiometry for in-vivo nail measurements

We have developed a new method for in-vivo human nail characterization by using opto-thermal transient emission radiometry (OTTER) and condenser-chamber TEWL (trans-dermal water loss) method – AquaFlux. With OTTER, we can measure nail water content, nail water concentration depth profiles, as well as topically applied solvent penetration through nail. With AquaFlux, we can measure nail transonychial water loss (TOWL). Combining the water content results with TOWL results, we can get the water diffusion coefficient of nail. Measuring the water diffusion coefficients of nail at different nail water concentration levels can also yield information on how nail diffusion coefficients change with water content. We will present the theoretical background, and experimental results on water concentration depth profile in nail, as well as topically applied solvent penetration through nail.

In vivo transungual iontophoresis: Effect of DC current application on ionic transport and on transonychial water loss

The potential use of iontophoresis to improve drug penetration into the nail has been suggested. However, there is little information concerning transungual iontophoresis in vivo. This work describes the application of transungual iontophoresis to six healthy human volunteers in order to investigate key issues such as the effect of current application on ionic transport and on transonychial water loss (TOWL), and the magnitude of the voltages required for a practical use of the technique. Each volunteer participated in three experiments: passive control, 0.2 mA anodal transungual iontophoresis and 0.2 mA cathodal transungual iontophoresis. A commercial electrode on a skin site was used to complete the electrical circuit. The outward transungual extraction of sodium and chloride ions by passive diffusion and iontophoresis was quantified. Iontophoresis enhanced chloride and sodium transport ~ 8 and 27 fold respectively compared to passive diffusion. Sodium transport numbers were measured to be t Na + = 0.51 ± 0.11. TOWL was used as a potential marker of nail damage and hydration. Basal TOWL was measured before each experiment, and the return to baseline values was monitored for 1 h after the treatment (passive or iontophoresis application) was finished. TOWL was increased after both iontophoretic and passive experiments and typically returned to baseline values in 1 h post-treatment. The voltage of the nail-to-skin circuit was monitored during iontophoresis and compared to those observed in a skin-to-skin circuit. Nail-to-skin circuit voltages were generally ~ 50 V when the current was started and dropped fast to 20–30 V, a value comparable to that observed in the skin-to-skin circuit. On the whole, the clear enhancement of ionic transport observed, the feedback from volunteers, the small effects in TOWL, and the magnitude of voltages indicate that nail DC current iontophoresis is feasible and probably a safe technique.

Tape stripping on a human nail: quantification of removal

Tape stripping is commonly used to investigate the stratum corneum (SC). This study assesses if protein quantitative tape stripping method was suitable for human nails. We used a colorimetric method to quantify proteins removed by the tape. Water barrier functions as a result of tape stripping were also observed by changes in transonychial water loss (TOWL) from the baseline. Using tape stripping, we observed no difference between nails in the protein quantity removed by tape stripping (P=0.39). The mean TOWL before and after tape stripping were 6.9 and 9.3 g/m2/h, respectively; this was significantly increased in tape stripped nails (P<0.0001). Tape stripping seems to be an effective method to extract proteins from human nail plate and may aid the study of nail structure and function. Further studies are needed to extend our results in terms of age, gender, ethnicity and disease.

A few aspects of transonychial water loss (TOWL): Inter-individual, and intra-individual inter-finger, inter-hand and inter-day variabilities, and the influence of nail plate hydration, filing and varnish

The aim of the study was to measure transonychial water loss (TOWL) in order to identify the extent of inter-individual, intra-individual inter-finger, inter-hand, and inter-day variabilities, and the influence of nail wetting, filing and varnishing on TOWL, with a view to determine parameters for the measurement of TOWL and its possible applications. Fingernail and toenail TOWL was measured using the condenser-chamber AquaFlux (Biox) and a specially designed Nail Adaptor supplied by Biox. A wide range of TOWL values (28–75 g/m 2 h for fingernails and 26–48 g/m 2 h for toenails) were found, with significant inter-individual variability. Intra-individual variability was lower; however, in the same individual, inter-finger, inter-hand/foot and inter-day variabilities were found, as well as a strong correlation between nail plate thickness and TOWL. Wetting the nails, even briefly, resulted in a significant rise in TOWL, which subsequently took much longer to return to control values. Filing the nail plate surface with a pharmaceutical file caused large increases in TOWL, whose profile (with number of filing strokes) was fairly different among individuals. As expected, nail varnish application reduced TOWL; the different extent of TOWL reduction by different varnishes suggests a potential use of TOWL measurements for product comparisons.

Transonychial water loss in healthy and diseased nails.

The objective of this study was to determine the transonychial water loss (TOWL) in both healthy and affected nails in different diseases and to compare it with the transepidermal water loss (TEWL). TOWL was measured by a new evaporimetric method: Plasticine was used to fix the protection cover of the evaporimeter probe to the nails. The TOWL behaved contrary to the TEWL. Affected nails in patients with atopic eczema (p <0.01), psoriasis (p<0.05) and onychomycosis (p<0.001) showed a significantly lower TOWL than did nails of healthy test subjects. The decrease in TOWL in diseased nails in comparison to healthy nails could be due to the formation of a stratum granulosum in atopic, psoriatic or fungus-affected nails, as this layer is normally absent in healthy nails.

Brittle nails. Objective assessment and therapy follow-up

The different methods that are available for the assessment and quantification of "brittle nails" and for the evaluation of various therapeutical approaches are compared. At this time, measurement of the swelling properties is the best documented and most reliable method for studying the treatment of brittle nails. Reliable qualitative data can also be obtained by scanning electron microscopy. Measurement of the transonychial water loss and assessment of thickness and density of nails by ultrasound have also been used successfully, but the methodology still has to be improved and the reproducibility, confirmed.

Transonychial water loss: relation to sex, age and nail-plate thickness.

The transonychial water loss (TOWL) was measured in 21 healthy volunteers with an evaporimeter, to establish the usefulness of this technique and study the influence of sex, age and nail-plate thickness. The median TOWL was 19.4 g/m2 h-1 and it decreased with increasing age (R = 0.51, P less than 0.018). The median transepidermal water loss (TEWLHAND) from the back of the hand was 16.0 g/m2 h-1 and from the dorsal side of the underarm (TEWLARM) it was 5.6 g/m2 h-1. The TEWLARM was significantly less than from any of the two other points studied (P less than 0.01), while there was no significant difference between the values obtained on the hand and the nail. TEWLARM had a median value of 6.4 g/m2 h-1 in men and 4.3 g/m2 h-1 in women (P less than 0.05) in this study. No significant correlation between nail-plate thickness, as measured by ultrasound 20 MHz A-scan, and TOWL was found. Measurements of TOWL are of interest and should be age-related. Further studies are needed to determine TOWL in various forms of nail pathology.