Wrinkles are visible markers of time on our skin. They result from an interplay between intrinsic aging and extrinsic influences. While external factors like sun exposure and lifestyle choices play a role, intrinsic aging, driven by mechanisms like cell dysfunction and the emergence of senescent cells, is the primary cause of wrinkles. In this article, we explore both intrinsic and extrinsic factors behind wrinkles.
Extrinsic vs. Intrinsic Damage
There are two kinds of damage to our skin: extrinsic damage and intrinsic damage.
1. Extrinsic damage is caused by things coming from outside of us or is caused by our behavior, like sun exposure, smoking, unhealthy food, taking specific medications, drinking too much alcohol, stress, specific repetitive facial expressions, sleep deprivation, and so on.
2. Intrinsic damage is the real and most important cause of wrinkles. It’s what happens in the body as a natural part of the aging process. This intrinsic aging process leads eventually to wrinkles on every body.
No matter how diligently you protect yourself from external factors such as sun exposure or maintain a healthy diet, wrinkles will inevitably develop, as they are a direct outcome of the aging process.
What Causes Skin Aging?
In essence, specific intrinsic aging mechanisms damage the stem cells and other cells in our skin, making them dysfunctional. That way, they cannot create new skin cells or maintain the skin properly by secreting collagen, elastin, and so on. This aging damage is caused by aging mechanisms like epigenetic dysregulation, mitochondrial damage, oxidative damage, genomic instability, protein accumulation, crosslinking, and altered intracellular communication. To learn more about these aging mechanisms, click here.
These aging mechanisms first damage all of the stem cells in the skin. That’s not good, given stem cells need to generate new skin cells, such as fibroblasts, keratinocytes and melanocytes, which build up and maintain the skin. For example, when the stem cells that create new melanocytes get damaged, we get gray hair. This is because melanocytes are cells that surround the hair root and pump melanin (a pigment with a brown or blackish color) into the hair root, giving hair its color. When skin stem cells cannot produce melanocytes anymore, we get grey hair (learn how to prevent or reduce grey hair).
When the skin stem cells cannot generate new skin cells anymore, the skin becomes depleted of cells like fibroblasts that produce collagen, elastin, and hyaluronic acid, all molecules that surround skin cells, glue them together and give elasticity, firmness and plumpness to our skin. These aging mechanisms also cause damage to the non-stem cells in our skin, like fibroblasts. And some of these aging mechanisms can also convert these normal, innocuous cells into dangerous cells: senescent cells.
Senescent Cells and Skin Aging
This brings us to another reason for skin aging besides skin stem cell depletion and dysfunction: the rise of senescent cells in our skin.
Senescent cells are normal cells that became too damaged. But instead of killing themselves, they keep lingering around in the skin, secreting all kinds of substances that damage the healthy neighboring skin cells.
The senescence-associated secretory phenotype (SASP) is the collection of substances secreted by senescent cells. One particular component is MMPs, which can remodel tissue. This is especially important in the context of skin and how collagen/extracellular matrix modeling occurs in aging and the presence of senescent cells in the skin organ (R).
Senescent fibroblasts, for example, damage healthy surrounding fibroblasts and other skin cells and contribute to wrinkles, loose sagging skin, age spots and other forms of pigmentation we see increasing during aging. Skin cells become senescent because of the sorts of damage we described before, such as damage to the genome, including the telomeres, mitochondrial dysfunction, epigenetic dysregulation and so on.
The Aged, Systemic Milieu Of Our Cells
The aging process involves a phenomenon known as “altered intracellular communication.” As we age, cells throughout our body increase the secretion of harmful substances, such as pro-inflammatory compounds. These detrimental agents, like those released by senescent cells, can adversely affect our cells, even in distant locations, including the skin. The systemic effect of inflammation, often referred to as “inflammaging,” although initially occurring in specific areas, can spread throughout the body, impacting multiple organs simultaneously.
Various substances can not only slow down aging, but also reduce wrinkles. Learn more here.