The relationship between the severity of coronary artery disease and skin measurement parameters

Improvement in Cutaneous Conditions Can Benefit Some Health Conditions in the Elderly

As we are aging, a number of cutaneous and extracutaneous disorders will be developed. Although the pathogenesis of these aging-associated disorders is not clear yet, abnormalities in the skin are linked to some aging-associated disorders at least to some extent. Inflammatory dermatoses such as psoriasis and atopic dermatitis predispose to the development of cardiovascular diseases, obesity and type 2 diabetes. In addition, both chronologically aged skin and individuals with some aging-associated systemic conditions display altered epidermal function, such as reduced stratum corneum hydration levels, which can provoke cutaneous inflammation. Because aged skin exhibits higher expression levels of inflammatory cytokines, which play a pathogenic role in a variety of aging-associated health condition, the association of the skin with some aging-associated disorders is likely mediated by inflammation. This postulation is supported by the evidence that improvement in either epidermal function or inflammatory dermatoses can mitigate some aging-associated disorders such as mild cognitive impairment and insulin sensitivity. This perspective discusses the association of the skin with aging-associated disorders and highlights the potential of improvement in cutaneous conditions in the management of some health conditions in the elderly.

"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.

Spatiotemporal monitoring of changes in oxy/deoxy-hemoglobin concentration and blood pulsation on human skin using smartphone-enabled remote multispectral photoplethysmography

We propose a smartphone-enabled remote multispectral photoplethysmography (SP-rmPPG) system and method to realize spatiotemporal monitoring of perfusion changes and pulsations of the oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb) information of the effective blood volume within light interrogated skin tissue beds. The system is implemented on an unmodified smartphone utilizing its built-in camera and flashlight to acquire videos of the skin reflectance. The SP-rmPPG method converts the RGB video into multispectral cubes, upon which to decouple the dynamic changes in HbO2 and Hb information using a modified Beer-Lambert law and the selective wavelength bands of 500 nm and 650 nm. Blood pulsation amplitudes are then obtained by applying a window-based lock-in amplification on the derived spatiotemporal changes in HbO2 or Hb signals. To demonstrate the feasibility of proposed method, we conduct two experiments on the skin tissue beds that are conditioned by occlusive maneuver of supplying arteries: one using the popular blood cuff pressure maneuver on the upper arm, and another artificially inducing a transient ischemic condition on the facial skin tissue beds by finger pressing on the supplying external carotid artery. The cuff experiment shows that the measured dynamic information of HbO2 and Hb in the downstream agrees well with the parallel measurements of oxygenation saturation given by the standard pulse oximeter. We also observe the expected imbalance of spatiotemporal changes in the HbO2 and Hb between the right and left cheeks when the transient ischemic condition is induced in the one side of facial skin tissue beds. The results from the two experiments sufficiently demonstrate the feasibility of the proposed method to monitor the spatiotemporal changes in the skin hemodynamics, including blood oxygenation and pulsation amplitudes. Considering the ever-growing accessibility and affordability of the smartphone to the general public, the proposed strategy promises the early screening of vascular diseases and improving general public health particularly in rural areas with low resource settings.