Our skin changes as we age. It becomes thinner and loses fat, making it less plump and smooth. Clinically, aged skin is characterized by wrinkles, sagging, age spots and dryness. Emphasizing laboratory and clinical research, this book comprehensively describes the molecular mechanisms of human skin-aging and age-related skin diseases. This includes

The aging process in the skin is complex and influenced by more intrinsic and extrinsic factors than any other body organ. The effects of these two types of factors overlap for the most part. The combined effects of these two aging processes also affect dermal matrix alterations. The main clinical signs of skin aging include wrinkling and irregular pigmentation, which are influenced by a combination of intrinsic and extrinsic (e.g., UV radiation, heat, smoking, and pollutants) factors. Histologically, collagen decreases, and the dermis is replaced by abnormal elastic fibers as a cause of wrinkle formation through the loss of skin elasticity. There have been numerous studies of skin aging performed to elucidate the underlying molecular mechanisms and to develop various antiaging therapeutics and preventive strategies. We summarized the molecular mechanisms and treatments of skin aging. Mainly UV radiation induces ROS formation and DNA damage, leading to increased production of MMPs and decreased production of collagen in keratinocytes and fibroblasts, which reflect the central aspects of skin aging. Besides UV radiation exposure, extrinsic factors including tobacco smoking, exposure to environmental pollutants, infrared radiation, and heat contribute to premature skin aging. Like UV radiation, these factors cause ROS formation and increase expression of MMPs, thus accelerating skin aging by inducing extracellular matrix (ECM) degradation. Accumulated collagen fibrils inhibit the new collagen synthesis and account for the further degradation of the ECM through this positive feedback loop. Accumulating evidence for molecular mechanisms of skin aging should provide clinicians with an expanding spectrum of therapeutic targets in the treatment of skin aging.

Numerous studies had been performed to elucidate the mechanisms of aging and to achieve rejuvenation, with some success reported in recent years. However, at present, the findings from those studies are not sufficient to resolve the issue of aging. This book presents an overview of recent topics on cellular aging and rejuvenation. In the early chapters, the molecular mechanisms of aging via the activities of clock and ion channel proteins, in addition to overall aspects, are discussed. In the latter part, the aging of the skin, immune system, and brain is discussed. This book will prove useful for those studying or developing new drugs to counter the aging process and will encourage the development of novel ideas for rejuvenation.

Skin is the most voluminous connective tissue of the body. Skin, like all other human organs, undergoes progressive alterations as a consequence of the passage of time (natural aging). However, human skin, unlike other organs, continuously experiences harmful exposure from environmental sources such as solar ultraviolet irradiation (photoaging). As the bulk of the skin is largely comprised of connective tissue collagen, the primary molecular features of aged human skin are reduced production of collagen and accumulation of damaged collagen. Age-related alterations of dermal connective collagen cause an aberrant tissue microenvironment, which deleteriously influence the risk of developing age-related skin diseases. This book comprehensively describes the molecular mechanisms of human skin connective tissue aging by emphasizing age-related dermal microenvironment as a strategy for improving our quality of life as well as for preventive and therapeutic intervention of age-related skin diseases. This book is an essential resource for the development of mechanisms-based anti-skin aging products.

The topic of skin aging is of growing importance to all working in the field of dermatology, aesthetic medicine and cosmetic medicine. Two internationally well-known and leading experts in the field present a comprehensive state-of-the-art review on all aspects of skin aging. With its clear, concise and reader-friendly format this book has all the potential to become the Bible of skin aging. Every specialist interested in dermatology, aesthetic medicine, cosmetic science, cutaneous biology and aging research will find indispensable information of great value for his or her daily work.