Review of Major Theories of Skin Aging

Abstract

Here we aim to describe each factor that leads to skin aging and describe their mechanisms. A PubMed database searches (from January 2004 to March 2014) using aging and skin as searched terms. There are substantial evidences showing that aging is associated with damage from free radicals represented by various reactive oxygen species (ROS). Mitochondria are producers and also targets of oxidative stress. The cycle of mitochondrial dysfunction can trigger the aging process. In the cellular senescence and telomeres theory, the diploid cells exhibit a limited proliferation potential. After a finite number of divisions, they enter a state of senescence with a stop replication in cell proliferation. It is suggested that aging is associated mainly with hyper-regulation of apoptosis. Obesity presumably accelerates the process of aging, which is aggravated by smoking. And the influence of the environment, called solar UV irradiation is of considerable importance to skin aging. There are several mechanisms that trigger the natural aging process and contribute to age-related changes, including oxidative stress theory of free radicals, the mitochondrial dysfunction, telomere shortening, UV radiation and other mechanisms that taken together or alone may or not accelerate the change in skin.

Anti-aging potential of fish collagen hydrolysates subjected to simulated gastrointestinal digestion and Caco-2 cell permeation

“…The skin is the largest organ of the human body and consists of the epidermis and the dermis. The epidermis, which is composed of keratinocytes, is the outermost layer of the skin and serves as a boundary between the environment and the body [1]. The underlying dermis layer is mainly comprised of collagen and elastin [2], which are produced by fibroblasts.…”

“…Skin aging occurs when dermal collagen is degraded, resulting in loss of skin tensile strength and stability [4]. Skin aging can be classified into two types with different causes: intrinsic aging, which occurs inevitably over time, and extrinsic aging, which is caused by ultraviolet (UV) radiation, air pollution, smoking, and poor nutrition [1]. These factors impair skin metabolism, resulting in degradation of the collagenous matrix through the actions of cell surface receptors, protein kinase signal transduction pathways, transcription factors, and enzymes [5].…”

Peptides-derived from Scales of Branchiostegus japonicus Inhibit Ultraviolet B-induced Oxidative Damage and Photo-aging in Skin Cells

“…특히 피부 세포가 UVB에 노출이 되면 직접적인 경로로 DNA 의 손상과 간접적인 경로인 활성 산소종(reactive oxygen species, ROS)이 생성되고 그 ROS로 인해 손상이 일어나 광노화 를 초래한다 [7,16,20]. UVB로 유도된 ROS 중 가장 높은 반응 성을 가진 hydroxyl radical은 L-tyrosine-tyrosinase 반응을 통 해서 생성된다.…”

Anti-aging and tyrosinase inhibition effects of Cassia fistula flower butanolic extract

“…Skin aging is a complicated biochemical progression resulting from many individual intrinsic and extrinsic factors such as age, hormones and exposure to UV light [1]. The progression occurs in the epidermal and dermal layers and is mainly related to extracellular matrix (ECM) degradation [2].…”