Diabetic and sympathetic influences on the water permeability barrier function of human skin as measured using transepidermal water loss: A case-control study

Is It Possible to Monitor the Safest Time to Perform Secondary Surgery on Free Flaps? A Clinical Evaluation of the Tewameter®

Background and Objectives: Postoperative monitoring, following free flap surgery, plays a crucial role in ensuring the survival of the flap. However, in microsurgery, not only the immediate postoperative monitoring period but also the choice of the right time for secondary surgeries is crucial for the free flap survival. There is no clear consensus concerning the right choice of timing for secondary surgery. Our aim was to evaluate transepidermal water loss (TEWL), with the objective evaluation tool Tewameter® in free flap surgery to monitor flap autonomization. Materials and Methods: Transepidermal water loss was assessed in 20 patients with microsurgically transplanted free anterior lateral thigh (ALTP) flaps. The transplantation of the ALTP-flap and the postoperative care were administered in accordance with the standard of care of the department. Measures were taken on the free flap and normal skin at follow-ups of 1, 3, and 6 months after initial free flap transplantation. Results: Transepidermal water loss gradually increased to the values found in normal skin, after 6 months. The differences between the two areas demonstrated the smallest variance after 6 months, specifically in the ALTP-flap region. The largest disparities were observed between month 1 and month 6, followed by month 3 and month 6, and month 1 and month 3. Conclusions: Free flap autonomization and physiology are complex processes. TEWL might be a valuable parameter to monitor flap autonomization. Our results indicate that TEWL in the free flap is nearly "normal" after six months. For a clear consensus of when to perform individual secondary surgery, further studies are needed.

Skin Homeostasis and Repair: A T Lymphocyte Perspective

Chronic, nonhealing wounds remain a clinical challenge and a significant burden for the healthcare system. Skin-resident and infiltrating T cells that recognize pathogens, microbiota, or self-antigens participate in wound healing. A precise balance between proinflammatory T cells and regulatory T cells is required for the stages of wound repair to proceed efficiently. When diseases such as diabetes disrupt the skin microenvironment, T cell activation and function are altered, and wound repair is hindered. Recent studies have used cutting-edge technology to further define the cellular makeup of the skin prior to and during tissue repair. In this review, we discuss key advances that highlight mechanisms used by T cell subsets to populate the epidermis and dermis, maintain skin homeostasis, and regulate wound repair. Advances in our understanding of how skin cells communicate in the skin pave the way for therapeutics that modulate regulatory versus effector functions to improve nonhealing wound treatment.

Effect of Boron on Sympathetic Skin Response in Rats

Background

Boron effects on reproduction and growth have been extensively studied in animals. Electrodermal activity (EDA) reflects the activity of eccrine sweat glands stimulated by the release of acetylcholine from sympathetic nerves.

Aim

In the presen study, it was aimed to examine the effect of boron, which was turned into cream, on sweat glands.

Methods

A cream form mixed with thyme oil was prepared for EDA recording. Our groups were formed as EDA recording gel (Group 1), cream with thyme oil (Group 2), cream containing 10% boron (Group 3) and cream containing 30% boron (Group 4). In each group, 3 months old, 10 male rats were used, and creams were applied to the soles of the hind extremities of the rats, EDA was recorded from this region after half an hour, and skin conductivity levels (SCL) were recorded as tonic (at rest) and phasic (with auditory sound stimulation).

Results

EDA results recorded in the morning were analysed with tonic and phasic recordings. In the morning SCL measurements, tonic SCL value of Group 4 was higher than the other groups (P < 0.001). Although the phasic SCL value was measured, it was significantly higher in Group 4 than in all groups (P < 0.0s).

Conclusion

EDA measurements showed that boron increased sweat gland activity by increasing sympathetic nerve activity.

Evaluation of Morphological and Structural Skin Alterations on Diabetic Subjects by Biophysical and Imaging Techniques

Diabetes causes increased production of advanced glycation end products (AGEs), which may lead to irreversible damage to collagen fibers, and early and more accentuated signs of skin aging. Thus, the objective of this study was to evaluate diabetic skin's mechanical and morphological characteristics and compare these to healthy skin. Twenty-eight female participants aged between 39 and 55 years were enrolled: half had type 2 diabetes, and the others were healthy. Wrinkles, transepidermal water loss (TEWL), stratum corneum water content, skin color, elasticity, morphological and structural characteristics of epidermis and dermis echogenicity were evaluated using biophysical and skin imaging techniques. Higher TEWL values were observed in participants with diabetes, who also showed lower skin elasticity and wrinkles with greater volume, area, and depth. In addition, the Reflectance Confocal Microscopy (RCM) imaging analysis showed that all participants with diabetes presented polycyclic papillae and deformed and amorphous collagen fibers. The obtained data showed significant differences between healthy and diabetic skin and could help develop more specific topical treatments to improve the treatment of skin conditions in people with diabetes. Finally, RCM is an advanced imaging technique that allows for a more profound analysis of diabetic skin, which could assist in the evaluation of dermocosmetic treatments to improve the skin alterations caused by this disease.

Impacts of Skin Eccrine Glands on the Measured Values of Transepidermal Water Loss

Transepidermal water loss (TEWL) is widely used to assess and quantify skin insensible water loss to assess skin's barrier function integrity. Low TEWL values are normally indicative of intact skin and a healthy functional barrier, whereas an increased TEWL reveals a disturbed or disrupted skin barrier. Because most skin sites at which these measurements are made have eccrine glands present, the contribution of the sweat gland activity to these measurements is variable and, in most cases, unknown. The separation between the contribution of water loss that is reflective of the skin barrier integrity versus that contributed via eccrine activation is not easy and is made more difficult since both components increase with increasing skin and environmental temperature. Endogenous factors that impact eccrine sweat gland activity include sympathetic nervous system activity, emotional stress, physical activity, eccrine gland density, and age. Exogenous factors that impact eccrine gland activity include ambient temperature and humidity and the climate where one resides. The aforementioned variables impact eccrine gland activity positively or negatively and therefore alter TEWL values accordingly. Although it may be theoretically possible to control all these factors, the difficulty in doing so results in only a few being controlled during most TEWL measurements. Such confounding processes may have impacted historical TEWL reference ranges and values previously reported. Thus, the impact of eccrine activation on standardly measured TEWL values is at this juncture unclear and may be a component contributing to some reported variability in TEWL values. To help clarify the issues, a literature review was conducted to investigate and summarize relevant prior research efforts and outcomes with respect to ways to consider eccrine activity in TEWL measurements and estimate the contribution of eccrine gland activity to TEWL values. Online databases such as Excerpta Medica Database (EMBASE), Public/Publisher Medline (PubMed), Elton B. Stephans Company (EBSCO), Google Scholar, and Wiley Online Library were searched with "transepidermal water loss" or "TEWL" in the title combined with "eccrine glands" or "sweat" anywhere in the text. The present findings indicate a multiplicity of biological and environmental variables impacting eccrine gland activity and thereby potentially affecting measured TEWL values. Even if laboratory conditions adhere to various guidelines and recommendations, it is not yet possible to separate the eccrine activation component from the parameter of true interest in the assessment of the skin's physiological barrier function except for full gland deactivation. The amount that such eccrine gland activation impacts the measured value of TEWL is generally not determined using currently available methods and the only sure way to eliminate a confounding effect is to inactivate the glands during such TEWL measurements. Because such eccrine gland deactivating approach is not usually desirable or even possible, other approaches would be recommended. One would be the development of a measuring device that could distinguish between the component of TEWL that is associated with the skin barrier function and the other that is attributable to sweat gland activation. Further research and development along these lines appear warranted.

Alterations in epidermal function in type 2 diabetes: Implications for the management of this disease

Epidermal function is regulated by numerous exogenous and endogenous factors, including age, psychological stress, certain skin disorders, ultraviolet irradiation and pollution, and epidermal function itself can regulate cutaneous and extracutaneous functions. The biophysical properties of the stratum corneum reflect the status of both epidermal function and systemic conditions. Type 2 diabetes in both murine models and humans displays alterations in epidermal functions, including reduced levels of stratum corneum hydration and increased epidermal permeability as well as delayed permeability barrier recovery, which can all provoke and exacerbate cutaneous inflammation. Because inflammation plays a pathogenic role in type 2 diabetes, a therapy that improves epidermal functions could be an alternative approach to mitigating type 2 diabetes and its associated cutaneous disorders.

"Normal" TEWL-How Can it be Defined?: A Systematic Review

BACKGROUND

Transepidermal water loss (TEWL), the total non-eccrine sweat water evaporating from a given area of epidermis over time, is a measurement of skin barrier integrity. Skin diseases (e.g. psoriasis and atopic dermatitis) often result in transient increases in TEWL, so knowledge of "normal" TEWL values may be used to predict disease progression in dermatological settings. Variables such as age, race, and anatomic location have been suggested to affect TEWL, but current regulatory agencies have failed to control for additional variables of interest. Thus, this review summarizes variables that may cause TEWL variation.

METHODS

A comprehensive literature search was performed using Embase, PubMed, and Web of Science to find human studies that provided data on variables affecting TEWL.

RESULTS

31 studies, analyzing 22 affecting TEWL, were identified. Variables causing increased TEWL were mask-use (n=1), Dry Eye Disease (n=1), Chronic Venous Disease (n=1), Coronary Artery Disease (n=1), age (infants vs. adults) (n=4), nourishment in infants (n=1), stress within individuals (n=2), Body Mass Index (n=2), bathing versus showering (n=2), and scratching/friction (n=1). Variables with decreases in TEWL were genetic variability with SNPs on chromosome 9q34.3 (n=1) and cancer-cachexia (n=1).

CONCLUSION

We summarized 12 variables that impact TEWL and are not typically controlled for in experimental settings. Therefore, defining normal TEWL may currently be problematic. Thus, regulatory agencies should provide stricter guidelines on proper measurement of TEWL to minimize human introduced TEWL variation, and we should continue to examine factors impacting individual skin integrity.

Diabetic Wound-Healing Science

Diabetes mellitus is an increasingly prevalent chronic metabolic disease characterized by prolonged hyperglycemia that leads to long-term health consequences. It is estimated that impaired healing of diabetic wounds affects approximately 25% of all patients with diabetes mellitus, often resulting in lower limb amputation, with subsequent high economic and psychosocial costs. The hyperglycemic environment promotes the formation of biofilms and makes diabetic wounds difficult to treat. In this review, we present updates regarding recent advances in our understanding of the pathophysiology of diabetic wounds focusing on impaired angiogenesis, neuropathy, sub-optimal chronic inflammatory response, barrier disruption, and subsequent polymicrobial infection, followed by current and future treatment strategies designed to tackle the various pathologies associated with diabetic wounds. Given the alarming increase in the prevalence of diabetes, and subsequently diabetic wounds, it is imperative that future treatment strategies target multiple causes of impaired healing in diabetic wounds.

Does sensitive skin represent a skin condition or manifestations of other disorders?

Sensitive skin or cutaneous sensory syndrome is defined as a skin condition that is hypersensitive to stimuli, presented with itching, irritant, erythema, and dryness. However, is it associated with more than impairment of epidermal functions, psychological stress and topical medication or products? We think that it can be a skin condition or manifestation of other cutaneous or extracutaneous disorders. In this paper, we brief relation of sensitive skin syndrome with cutaneous and extracutaneous disorders, clinically, and pathophysiologically.

Enrichment of Short-Chain Ceramides and Free Fatty Acids in the Skin Epidermis, Liver, and Kidneys of db/db Mice, a Type 2 Diabetes Mellitus Model

Patients with diabetes mellitus (DM) often suffer from diverse skin disorders, which might be attributable to skin barrier dysfunction. To explore the role of lipid alterations in the epidermis in DM skin disorders, we quantitated 49 lipids (34 ceramides, 14 free fatty acids (FFAs), and cholesterol) in the skin epidermis, liver, and kidneys of db/db mice, a Type 2 DM model, using UPLC-MS/MS. The expression of genes involved in lipid synthesis was also evaluated. With the full establishment of hyperglycemia at the age of 20 weeks, remarkable lipid enrichment was noted in the skin of the db/db mice, especially at the epidermis and subcutaneous fat bed. Prominent increases in the ceramides and FFAs (>3 fold) with short or medium chains (<C26) occurred in the skin epidermis (16NS, 18NS, 24NS, 16NDS, 18NDS, 20NDS, 22NDS, 24NDS, C16:1FA, C18:2FA, and C18:1FA) and the liver (16NS, 18NS, 20NS, 24:1NS, 18NDS, 20NDS, 22NDS, C16:1FA, C18:2FA, C18:1FA), whereas those with very long chains were not affected. In the kidney, only slight increases (<3 fold) were observed for 16NS, 18NS, 20NS, 26NDS, C26FA, and C22:1FA. Consistently, LXRα/β and PPARγ, nuclear receptors promoting lipid synthesis, lipid synthesis enzymes such as elongases 1, 4, and 6, and fatty acid synthase and stearoyl-CoA desaturase were highly expressed in the skin and livers of the db/db mice. Collectively, our study demonstrates an extensive alteration in the skin and systemic lipid profiles of db/db mice, which could contribute to the development of skin disorders in DM.

Comparative study of transepidermal water loss in patients with and without hyperhidrosis by closed-chamber measurer in an air-conditioned environment

Objective

To evaluate the difference in transepidermal water loss in patients diagnosed with hyperhidrosis and healthy subjects, in an air-conditioned environment.

Methods

Twenty patients diagnosed with hyperhidrosis and 20 healthy subjects were subjected to quantitative assessment using a closed-chamber device, in six previously established sites.

Results

The measurements showed different transepidermal water loss values for healthy subjects and patients with hyperhidrosis, especially in the hands and feet. In the Control Group, the median for the hands was 46.4g/m²/hour (p25: 36.0; p75: 57.6), while in the Hyperhidrosis Group, the median was 123.5g/m²/hour (p25: 54.3; p75: 161.2) – p<0.001. For the feet, the Control Group had a median of 41.5g/m²/hour (p25: 31.3; p75: 63.5) and the Hyperhidrosis Group, 61.2g/m²/hour (p25: 32.3; p75: 117) – p<0.02. Measurements of the axillas also showed differences. In the Control Group, the median was 14.8g/m²/hour (p25: 11.8; p75: 19.0) and, in the Hyperhidrosis Group, 83.5g/m²/hour (p25: 29.5; p75: 161.7) – p<0.001.

Conclusion

Measuring transepidermal water loss is sufficient for diagnosis and follow-up of patients with hyperhidrosis.