Transcript collagen
Collagen: Structure and Function Course Author—Dr. Zoe Draelos, M.D. • Nu Skin Professional Advisory Board Member. • Board certified dermatologist in High Point, North Carolina, and clinical associate professor of dermatology at Wake Forest University School of Medicine, Winston-Salem, North Carolina. • Board of directors member for and fellow of the American Academy of Dermatology. • Author of Cosmetics in Dermatology; has written 240 published papers and serves on five journal editorial boards. Did You Know? Collagen makes up 75 percent of our skin and more than a third of the body's protein is collagen? Find out more about collagen in this course. Dermis Collagen Fibers Objectives After viewing this course, you should have an understanding of the following: • Basic structure and function of collagen • Relationship between collagen and beauty • The collagen production process • How collagen is broken down • How to preserve and promote healthy collagen levels Previous Curriculum Review—The Skin The skin is a complex organ composed of multiple layers. All layers of the skin can be divided into two main sections: • Epidermis • Dermis Beneath these sections is a subcutaneous layer of fat called the hypodermis. While not an official section of the skin, the hypodermis provides essential support. Epidermis Dermis Hypodermis Muscle Previous Curriculum Review—Dermis The dermis is a fibrous, mesh-like network of tissue that provides structure and gives skin its resilience. Major components of the dermis include the following: Epidermis Dermal Epidermal Junction Mast Cell • Collagen • Elastin • Glycosaminoglycans Dermis Elastin Fiber • Blood and lymph vessels • Specialized cells: mast cells and fibroblasts Collagen Fiber Glycosaminoglycans Blood Vessels Fibroblast Cell What Is Collagen? What Is Collagen? Collagen is the body’s major structural protein and is composed of three protein chains wound together in a tight triple helix. This unique structure gives collagen a greater tensile strength than steel. Dermis Collagen Fibers What Is Collagen? Approximately 33 percent of the protein in the body is collagen, supporting tissues and organs, and connecting these structures to bones. In fact bones are also composed of collagen combined with certain minerals such as calcium and phosphorus. What Is Collagen? Collagen plays a key role in providing the structural scaffolding surrounding cells that helps to support cell shape and differentiation, somewhat like steel rods reinforce a concrete block. The mesh like collagen network binds cells together and provides the supportive framework or environment in which cells develop and function, and tissues and bones heal. Without collagen the body would literally fall apart. Collagen and Beauty Collagen and Beauty Epidermis Dermis Collagen Fibers The skin is composed mostly of collagen proteins—about 75 percent—so the smooth, plump appearance of young, healthy skin is due in large part to the presence of healthy collagen levels. Found in the dermis layer, the meshlike framework of collagen gives the skin its strength and durability. Collagen and Beauty The breakdown of healthy collagen and the decline in collagen production leads to the development of unwanted wrinkles and the appearance of aged skin. Collagen and Beauty Beauty seekers around the globe search for new ways to boost collagen levels and repair past collagen damage, going so far as to inject collagen proteins into the skin to plumb wrinkles and add volume to the lips. Collagen Synthesis Collagen Synthesis Collagen is synthesized by fibroblasts—specialized skin cells located in the dermal layer of the skin. Fibroblasts also produce other skin structural components such as elastin and glucosaminoglycans (GAGs). Elastin gives the skin its ability to snap back. GAGs make up the ground substance that keeps the dermis hydrated. Fibroblasts Collagen Synthesis In order to signal or turn on the production of skin structural proteins, fibroblast cells have specially shaped receptors on their outside membranes that act as binding sites into which signal molecules with a matching shape, can fit. When the receptors are bound by the correct combination of signal molecules, called fibroblast growth factors (FGFs), the fibroblast begins the production of collagen. Collagen Synthesis Fibroblasts first produce short collagen subunits called procollagen, which are transported out of the fibroblast cells and then later joined together to form the complete collagen molecule. Vitamin C plays a key role in many steps of this process. Without sufficient levels of vitamin C, collagen formation is disrupted. This leads to a wide variety of disorders such as scurvy, a disease where the body cannot produce collagen and essentially all support structures deteriorate and the body falls apart. Collagen Synthesis Collagen synthesis occurs continuously throughout our lives to repair and replace damaged collagen tissue or build new cellular structures. With age collagen levels decline as a result of decreased production and increased degradation. Collagen Degradation Collagen Degradation The degradation and recycling of old and damaged collagen is a healthy natural process used to create protein fragments needed to build new cellular structures as in the healing process. Although the breakdown of collagen is a necessary process, UV radiation and environmental stressors push collagen degradation into overdrive. Free radicals induced by UV radiation attacking a cell Collagen Degradation There are two main ways that UV light and other environmental stressors decrease healthy collagen levels: • Ultraviolet rays and environmentally induced free radicals directly damage/mutate fibroblast DNA. When the genetic blueprint is mutated weakened collagen fibers are produced. • Free radicals from UV radiation and other environmental stressors oxidize and damage the collagen fibers. Collagen Degradation Environmental stressors such as UV radiation, ozone, pollution, and cigarette smoke—and the resulting inflammation—all produce free radicals that oxidize and weaken the actual collagen fiber. Also, in response to this free radical oxidation, excess amounts of metalloproteinase (MMP) enzymes are produced. Collagenase is the main MMP that degrades collagen. Collagen Degradation Remember, the normal function of metalloproteinases (specifically collagenase) is necessary to heal sun-injured or free radical damaged tissue as it creates building fragments used in the formation of new collagen. As cellular processes and available energy decline, these enzymes become dysfunctional and overly active, resulting in the formation of disorganized areas within the collagen matrix, referred to by dermatologists as solar scars. These weakened areas develop into wrinkles. Protecting and Promoting Collagen Protecting Collagen The first step in maintaining a healthy, youthful looking appearance is the protection of current collagen levels. There are two main ways to protect healthy collagen and prevent future collagen degradation: • Avoid UVA and UVB radiation. • Prevent free radical damage with a complete antioxidant defense network. Protecting Collagen Exposure to ultraviolet (UVA and UVB) radiation emanating from the sun is the most prolific cause of premature skin aging, accounting for an estimated 90 percent of the signs associated with aging skin. UV exposure must be limited and individuals should wear a daily sunscreen to protect healthy collagen. Many skin care companies understand this need and incorporate sunscreens into their daytime moisturizers. Protecting Collagen The second preventative step in protecting existing and future collagen levels is supplementation with both oral and topical antioxidants. As antioxidants fight free radicals from UV light, ozone, pollution, cigarettes, and internal metabolic processes, they prevent the degradation of existing collagen fibers and protect the healthy function of fibroblast cells. Protecting Collagen Antioxidants work optimally as a network to protect cellular health and viability. Some antioxidants in the network fight free radicals directly enabling other antioxidants to perform their critical functions. Key antioxidants in the defense network are carotenoids, CoQ10, and Vitamins C and E. Vitamin C CoQ10 CoQ10 (Carotenoids) Promoting Collagen There are many ways in which to promote the synthesis of new, healthy collagen: • Provide the skin with a reservoir of vitamin C. • Chemical exfoliation with acids. • Supplement with collagen stimulating peptides. Promoting Collagen As a necessary component in the synthesis process of collagen, vitamin C is proven to increase production. One study showed prolonged exposure of human connective tissue cells to vitamin C stimulated an eight-fold increase in the synthesis of collagen (Murad et al., 1981). Promoting Collagen Chemical exfoliants, such as alpha hydroxy acids and poly hydroxy acids break the bonds between cells of the stratum corneum and slough away dead skin. Consistent exfoliation stimulates cell renewal. Chemical exfoliation has also shown to increase dermal thickness. Scientists attribute this thickening to the synthesis of glycosaminoglycans and collagen within the dermis. Promoting Collagen Fibroblasts are naturally stimulated to begin the synthesis of collagen when specific combinations of peptide signal molecules (fibroblast growth factors) bind to receptor sites on the fibroblast membrane. These signal molecules can be supplemented topically and help to boost collagen production. Some skin care companies are including these peptide fragments in their treatment products. Collagen Review Collagen—Review • Collagen is a major structural protein that plays a key role in providing the structural scaffold for cells, tissues, and organs. Without collagen the body would fall apart. • Collagen gives the skin its strength and durability and is responsible for the smooth, plumb appearance of young, healthy skin • Fibroblast growth factors bind to fibroblast receptors to trigger production of collagen. Vitamin C is essential for collagen synthesis. • UV radiation and environmental stressors stimulate collagenase which increases the degradation of collagen. • Three ways to protect and promote collagen are consistently wearing sunscreen, chemically exfoliating and using products that contain Vitamin C. Test Your Knowledge Congratulations! You have completed the Collagen: Skin Structural Protein course.