Exploring the decline of human skin barrier function with ageing, and the impact of ethnicity and UVR exposure

人体皮肤是保护身体免受环境伤害的重要物理屏障，尤其是阳光中的紫外线辐射。皮肤还具有多种生理功能，包括免疫监视、体温调节和水分流失控制。人体皮肤的表皮在防止体内水分和溶质过多流失方面起着关键作用。表皮屏障功能是由颗粒层和疏水、富含脂质的角质层组成的紧密连接复合物维持的。屏障功能的破坏与干燥和更严重的炎症性皮肤病（如特应性皮炎和牛皮癣）有关。因此，维持一个功能性的表皮屏障对于最佳的皮肤功能和环境保护至关重要。皮肤功能随着年龄的增长而下降，包括屏障功能，并受到急性和慢性紫外线照射的影响，但种族对这些的影响尚不清楚。来自不同地理血统的个体的皮肤不仅在色素沉着上不同，而且在表皮厚度和真皮-表皮交界处卷积等形态学特征以及真皮基质的组成上也不同。因此，假设表皮屏障功能也可能不同。该项目的目的是研究表皮屏障的成分和功能如何随着年龄的增长而变化，包括慢性和急性紫外线照射的影响，以及不同种族的个体之间的差异。利用一系列实验室技术和体内评估，本研究将探索人类皮肤表皮屏障关键成分的数量和分布。此外，局部防晒霜在急性UVR暴露后防止表皮屏障变化的能力将被检查。研究结果将对我们对皮肤生物学和表皮屏障功能的理解做出重大贡献，并可能对阳光照射和光防护的公共卫生信息产生影响。此外，它将为保护和修复皮肤屏障的护肤产品和疗法的开发提供信息，以应对老化和阳光照射，以满足不同人群的需求。因此，这个项目汇集了Boots/ no . 7的两个战略主题领域——所有生命阶段的护肤和所有种族的护肤。

Human skin provides a crucial physical barrier to protect the body against environmental insults, notably ultraviolet radiation (UVR) in sunlight. The skin also has several physiological functions including immune surveillance and the control of thermoregulation and water loss. The epidermis of human skin has a key role in preventing excessive loss of water and solutes from the body. Epidermal barrier function is maintained by tight junction complexes in the stratum granulosum, and components of the hydrophobic, lipid rich stratum corneum. Disruption of barrier function is associated with xerosis and more severe, inflammatory skin conditions such as atopic dermatitis and psoriasis. Thus, maintaining a functional epidermal barrier is vital for optimum skin function and environmental protection.The function of skin declines with age, including barrier function, and is influenced by acute and chronic UVR exposure but the impact of ethnicity on these is unknown. Skin from individuals of different geographical ancestry differs not only in pigmentation, but in morphological features such as epidermal thickness and dermal-epidermal junction convolution, and in the composition of the dermal matrix. It is therefore hypothesised that epidermal barrier function may also differ. The aim of this project is to examine how components and function of the epidermal barrier change with ageing, including the impact of chronic and acute UVR exposure, and how this may differ between individuals of different ethnicity. Using a range of laboratory techniques and in vivo assessments, this research will explore the quantity and distribution of key components of the epidermal barrier in human skin. Additionally, the ability of topical sunscreen to protect against changes in the epidermal barrier following acute UVR exposure will be examined.Study findings will make a significant contribution to our understanding of skin biology and epidermal barrier function and may have implications for public health messaging on sunlight exposure and photoprotection. Moreover, it will inform development of skin care products and therapies for the protection and restoration of the skin barrier with respect to ageing and sunlight exposure that will meet the needs of our diverse population. Thus, this project brings together two of the strategic topic areas for Boots/No7 - Skincare for all life stages and Skincare for all ethnicities.