Question

Hyaluronic acid (HA): (P.S This is a biology related course, but theres also some chemistry..)

The premise for adding HA to moisturisers is that aging skin is associated with loss of skin moisture. The key molecule involved in skin moisture is hyaluronic acid. 1g of HA can attach to and hold approximately 6L of water. HA is composed of repeating disaccharides (two sugar molecules), D-glucuronic acid and N-acetyl-D-glucosamine. Depending on the length of the repeating disaccharides, the molecule can be low molecular weight (short chains) or high molecular weight (long chains). Within the human body, HA has a half-life of only 3-5 minutes in the blood, less than a day in the skin and 1 to 3 weeks in cartilage

I need some experts to help answer these questions. Any help is welcome! Thank you :)

• How do the sex hormones affect skin aging?
• In humans where is HA found?

• What are the functions of HA?
• HA is synthesized by specific enzymes called HA Synthases primarily in mesenchymal cells. HA is transported across the cell plasma membrane to the ECM through pore-like structures. The HA receptor on the cell surface (which imports HA into the cell) is CD44 which is found on virtually all cells. This tells us that that HA requires transport to move across the cell plasma membrane, would you expect that this would affect delivery of the topical creams? In answering this question think about whether HA is required to be extra or intracellular to be effective.
• Where is endogenously (synthesised within the body) made HA located in the integument?
• Does endogenous HA penetrate past the lipid-rich stratum granulosum? If not, why not? With respect to what you have been taught regarding the epidermis, what might this mean for exogenous (external) hydrophilic topical treatments reaching the lower levels of the epidermis?

Answer 1

How do the sex hormones affect skin ageing?

Ans: Estrogen is an important female hormone secreted by the oraries in a female.. It preserves the elasticity and moisture content of the skin. It can increase collagen production in the skin to maintain it's thickness and hydration.

Testosterone, which is found in both men and women, manages sebum production. Sebum is an oily liquid secreted by the sebaceous glands. Progesterone helps balance out the sebum produced by testosterone to keep our skin nourished and hydrated but not over oily. These hormones, called sex hormones can make our skin look youthful and glowing when work in balance.

In humans where is HA found?

Ans: HA is found naturally in almost every cell of our body The Golgi bodies are responsible for the secretion or formation of HA. It is found in greatest concentrations in the skin tissue.

What are the functions of HA?

Ans: It's main function is to retain water to make our skin lubricated and moist.. It accelerates wound healing. It regulates inflammation levels and promotes the formation of blood vessels in damaged area. In joints, it keeps the space between the bones well lubricated.

Where is HA located in the integument?

Ans: Deep underlying dermal cells and epidermal top layers.