Tag Archives: collagen

What Can Different Types of Facial Wrinkles Tell Us?

Few people enjoy having wrinkles. Some people spend a lot of time, money and efforts trying to reduce the wrinkles on their face, while others simply appreciate them as something naturally occurs with aging. Regardless, wrinkles are always associated with aging. However, if we look into what different types of wrinkles are and how they form, we will find that not all wrinkles are bad. Not all wrinkles are caused by aging, and not all wrinkles should be treated the same way. Here, we introduce different types of facial wrinkles categorized by plastic surgeon and their corresponding treatment.

A person smiling that shows some wrinkles on her face.
The wrinkles created by the motion of smiling are dynamic wrinkles. They will disappear once the smile stops. Credit: Masterfile.

In general, there are two main types of wrinkles, dynamic wrinkles and static wrinkles. Dynamic wrinkles are the type of wrinkles that only appear when you make expressions such as smiling, laughing, or frowning. These wrinkles disappear once your expressions stop. The facial muscles have enough elasticity to return to their original positions. These are temporary wrinkles that everyone may have, even little kids!

Static wrinkles, on the other hand, are wrinkles that form when your muscles cannot return to their original position due to gravity and loss of collagen and elastin. These wrinkles cannot disappear like the dynamic wrinkles. When the collagen fibers become thinner, the skin loses elasticity and gets more wrinkles, whose width and height grow with age. (Lemperle, 2001) Lemperle et al. from the University of California put these wrinkles into three categories.

Three hand-drawn figures that show textures of different wrinkles.
Figures that show the textural change of skin experiencing (a) superficial wrinkles, (b) mimetic wrinkles, (c) folds. Source: A Classification of Facial Wrinkles.

The first type is superficial wrinkles. These are the less severe wrinkles that only involve textural changes of the skin surface. These wrinkles lines are separate lines at first but will gradually group together. (Arumugam, 2015) Common causes are aging, excessive exposure to UV light, and gravity. Superficial wrinkles, according to Lemperle, can be reduced or removed by chemical peeling (applying chemical solution on the face to peel off the top layer and then grow it back), or laser resurfacing. (Lemperle, 2001)

A figure with 2 side-by-side photos that show the effect of laser resurfacing before and after the treatment. The wrinkles of the person's face reduces.
Before and after laser resurfacing. Credit: Tahoe Aesthetic Medicine.

The second type is mimetic wrinkles. These are more severe and visible dermal creasing. Major causes include aging and repeated dramatic facial expression. (Arumugam, 2015) Because the facial creasing is deeper, the reduction methods include more complicated procedures such as muscle resection (cut out a portion of muscle and inserted the shortened muscle at the same place), botulinum toxin (a neurotoxic protein), or skin filler injection. (Lemperle, 2001)

The picture shows a person's lower half of the face with dash line indicating where the nasolabial line is. A needle is pointing at the dash line mimicking the process of skin filler injection.
Skin filler injection to reduce the effects of nasolabial lines. Credit: Filling in Wrinkles Safely

The last type is folds, the part of the face where droopy skin overlaps. Folds and mimetic wrinkles usually occur together. To correct the overlapping skin, tightening procedures such as blepharoplasty (surgery that repairs droopy eyelids), face lift, or skin excision are needed. (Kligman, 1985)

Noticeably, researchers have discovered that wrinkles formation may be different by gender, race, etc. For example, women in general have finer and less apparent wrinkles than men because their skin is thinner and softer. (Wu, 1995) Asian skin connects more firmly to the tissues underneath because of its thicker dermis and higher collagen density. Therefore, the repetitive pulling of the skin surface affects wrinkles on Asians and Caucasians differently. (Ahn, 1999)

Wrinkles are nothing horrible. They are something that everyone has or will have in the future. There is nothing wrong with wanting to reduce the wrinkles on your face, either. Just remember that there are many types of wrinkles and each of them requires a bit of a different treatment. Spending some time finding the appropriate treatment will most likely save you more time, money, and effort in the future.

Sources:

[1] Lemperle, Gottfried, et al. “A Classification of Facial Wrinkles.” Plastic and Reconstructive Surgery, vol. 108, no. 6, 2001, pp. 1751–1752., doi:10.1097/00006534-200111000-00050.

[2] Arumugam, P, et al. “Facial Forehead Wrinkles Detection using Colour based Skin Segmentation.” Advances in Natural and Applied Sciences, Aug. 2015, pp. 71–80., doi:10.22587/anas.

[3] Kligman, A.M., et al. “The Anatomy and Pathogenesis of Wrinkles.” British Journal of Dermatology, vol. 113, no. 1, 1985, pp. 37–42., doi:10.1111/j.1365-2133.1985.tb02042.x.

[4] Wu, Yin, et al. “A Dynamic Wrinkle Model in Facial Animation and Skin Ageing.” The Journal of Visualization and Computer Animation, vol. 6, no. 4, 1995, pp. 195–205., doi:10.1002/vis.4340060403.

[5] Ahn, Ki-Young, et al. “Botulinum Toxin A for the Treatment of Facial Hyperkinetic Wrinkle Lines in Koreans.” Plastic & Reconstructive Surgery, vol. 105, no. 2, 2000, pp. 778–784., doi:10.1097/00006534-200002000-00050.

How Mice Could Help You Regenerate a Lost Limb

If you have ever experienced a nasty scrape or burn, you know the process of healing is not very fun. Human skin can take several weeks to regenerate after an injury and that often comes with a fair amount of pain. For a bigger injury that involves tissue damage, there is often little the human body can do to regenerate larger parts. However, thanks to a small rodent – the African spiny mouse – regenerative medicine for humans could be making huge advances in the near future.

The concept of regeneration is not something new in the animal world – we have seen creatures like salamanders regenerate lost tails and starfish regrow lost limbs. However, the African spiny mouse is the only mammal ever observed to be able to completely regenerate tissue such as skin, fur, hair follicles, sweat glands, and even cartilage. Being able to quickly shed skin caught in the mouths of large predators comes in handy for the mouse to be able to escape, but they must also be able to quickly heal those wounds.

African spiny mice in a research lab have spiny hair shown in (a) and (b). A skin wound was administered to a mouse in (c). Scabbing has occurred over the full injury as seen in (d) by Day 3. By Day 30, the original wound has healed and new hair follicles have been regenerated as seen in (e) and (f).
Figure 1. African spiny mice in a research lab have spiny hair shown in (a) and (b). A skin wound was administered to a mouse in (c). Scabbing has occurred over the full injury as seen in (d) by Day 3. By Day 30, the original wound has healed and new hair follicles have been regenerated as seen in (e) and (f). Source: Seifert, A., Kiama, S., Seifert, M. et al. Skin shedding and tissue regeneration in African spiny mice (Acomys). Nature 489, 561–565 (2012). https://doi.org/10.1038/nature11499.

How exactly does this happen? Researchers have found that the skin of the spiny mice is much weaker than that of most other mammals – think 20 times weaker than the skin of your regular old house mouse. Upon being handled, the skin is quick to shed leaving gaping wounds across the backs of these mice. This is due to the density of hair follicles found in their skin – a greater proportion of follicles means there is much less connective tissue to hold the skin leading to very easy tears. The weakness of the skin is contrasted by the rapidity by which it heals – the wounds can shrink to two thirds of their original size in a single day!

To understand a little bit more about the biomechanics of this process, we must look at how exactly the skin heals. As it turns out, collagen, the structural protein found in tissues which is responsible for skin elasticity among other things, is partly responsible for this phenomenon. Whereas mammals like you and I heal injuries through the generation of dense layers of collagen fibers aligned in parallel layers, these mice produce collagen fibers in crisscross networks that resemble the original makeup of tissue. This leaves the healed skin completely scar-free.

In addition, researchers have noted that ear wounds in the mice heal in a way similar to salamander tail regeneration. When a mouse’s ear gets injured, a ball of cells forms at the site of the wound that resembles cells in the embryonic state. This cell clump, called a blastema, is what allows the lost tissue to regrow on the ear. Scientists hope to use this information to study regeneration of tissue in humans.

An experiment was performed on both an African spiny mouse (Acomys) and another genus of rodents comparable to a house mouse (Mus) by making 4mm punctures in each species' ears. The size of the puncture was then observed over the following days showing that Acomys completely healed the ear puncture after 56 days while the size of the ear puncture in Mus remained relatively the same size showing no regeneration.
Figure 2. An experiment was performed on both an African spiny mouse (Acomys) and another genus of rodents comparable to a house mouse (Mus) by making 4mm punctures in each species’ ears. The size of the puncture was then observed over the following days showing that Acomys completely healed the ear puncture after 56 days while the size of the ear puncture in Mus remained relatively the same size showing no regeneration. Source: Matias Santos D, Rita AM, Casanellas I, et al. Ear wound regeneration in the African spiny mouse Acomys cahirinus. Regeneration (Oxf). 2016;3(1):52-61. Published 2016 Mar 9. doi:10.1002/reg2.50.

While there is still more research to do on the healing mechanism of the spiny mice tissue, the research done on these little mammals provides an excellent foundation for regenerative medicine for humans – something that studying regeneration in other animal species has not been able to accomplish. Being able to regenerate a lost limb was something once found only in science-fiction but could be a real possibility in the future.

Read More:

Insights into the regeneration of skin from Acomys, the spiny mouse

Optimal skin regeneration after full thickness thermal burn injury in the spiny mouse, Acomys cahirinus

Unique behavior of dermal cells from regenerative mammal, the African Spiny Mouse, in response to substrate stiffness

African spiny mice can regrow lost skin

Why your scar tissue isn’t an issue

What do knee scrapes, adolescent acne, and paper cuts have in common? They all have the potential to leave a nasty scar. For people who have undergone trauma that results in serious wounds, especially on the face, scar aging is a serious concern. What are scars, and why does scar tissue tend to look different than regular skin as aging occurs?

In 1861, Karl Langer began observing the nature of the skin’s tensile properties. He cut small, circular holes into cadavers, and looked to see where on these holes the skin pulled the most. From these experiments, he developed “Langer’s Lines,” which he asserted were lines of tension all around the human skin. Later, Borges noticed that Langer’s lines only applied to cadavers, and began to perform similar experiments on live people to see if he saw different results. He pinched the skin of live people, and then saw how the direction of pinching impacted the length of the wrinkle formed. From these experiments, he identified RSTL, or relaxed skin tension lines. More and more researchers after Langer and Borges investigated the “tension line” phenomena, and they all noticed the same thing: wounds cut across these lines always led to nastier, uglier scars than wounds parallel to the tension lines. Why would that happen?

Figure 1 outlines the differences of Langer's lines, Kraissl's lines, and Borges's RSTL on the human face.
Image courtesy of MedMedia

To answer this question, let’s first identify the cellular mechanisms at work during healing. According to David Leffell of the Yale School of Medicine, there are three key stages of scar formation. The first stage of scar formation is inflammation. This happens right after the wound is incurred. Blood flows to the site, and tissue called granulation tissue begins to form at the base of the wound. Next is proliferation, when that granulation tissue helps the surrounding fibroblast cells to duplicate as quickly as possible. Fibroblasts are very important; they are the cells that produce collagen, a key protein in tissue formation. During proliferation, more and more fibroblasts fill the site, and they begin rebuilding the collagen networks for new skin. The final stage of scar formation is maturation/remodeling, when fibroblast levels decrease slowly as fresh tissue is rebuilt.

This figure shows each stage of wound healing, as is outlined by the supporting paragraph.
Image courtesy of biodermis.com

Because scars are formed differently than regular skin, they also tend to age differently. Normal consequences of skin aging can be seen around us in older people every day. As you may notice in your parents and grandparents, older skin tends to be dry, rough, wrinkly, and sometimes discolored. While these changes can also occur within scar tissue, the biggest factor in scar tissue aging is the difference in the rate of skin cell renewal. Skin cell renewal occurs when new skin cells travel from the basal layer of the skin up to the epidermis. Scar tissue’s renewal rate is different than normal skin’s renewal rate. This is why adults recover from wounds more slowly than young people – there is a greater difference between their cell renewal rates. The age at which the scar was formed, and the quality of the care provided, are critical in evaluating how well the scar will age.

If you’re interested in learning more about how that cut on your hand might heal and age, watch this video from TED-Ed, or for more detailed reading, check out this article.

Ankle Sprains: An Epidemic in the World of Athletics

Have you ever been out running on a gorgeous fall day, only to have the run cut short by a painful misstep on a tree root covered by leaves? I have, and let me tell you – it’s awful! And even if you aren’t a runner, according to the Sports Medicine Research Manual, ankle sprains are a common, if not the most common, injury for sports involving lower body movements. Now, the solution to preventing this painful and annoying injury could be as simple as avoiding tree roots and uneven ground, but the real problem behind ankle sprains deals with the anatomy of the ankle.

The ankle is made up of many ligaments, bones, and muscles. However, when sprained, it is the ligaments that are mainly affected. Connecting bone to bone, ligaments are used to support and stabilize joints to prevent overextensions and other injuries. The weaker a ligament is, the easier it is to injure. There are three main lateral (outer) ligaments supporting the ankle joint that can become problematic: the anterior talofibular ligament, the calcaneofibular ligament and the posterior talofibular ligament. According to a study from Physiopedia, these lateral ligaments are weaker than those on the interior (medial) of the ankle, with the anterior talofibular ligament being the weakest.

An image depicting the various ligaments of the ankle, both lateral and medial.
Anatomy of the ankle, highlighting the lateral and medial ligaments

The next question that has to be asked is why are these ligaments so much weaker than other ones? The answer to this question is based on their physical make up. Ligaments are made of soft tissue that has various collagen fibers running parallel to each other throughout it. The more fibers there are, the more structure and rigidity there is. Think of the fibers as a rope: The rope can stretch to a certain point, but once it hits that point it will snap and break. But if you have a thicker rope (such as the medial ligaments), it becomes much harder to break.

The ligaments on the outer part of the ankle have fewer collagen fibers than those on the inside of the ankle. Thus, when the ankle is moved in an awkward position, it is more likely that the lateral ligaments will break.

Once you sprain your ankle, the focus turns to treatment. Treatment will differ slightly for every individual depending on the severity of the ankle sprain. The simplest way to treat a sprained ankle is to follow the RICE (Rest, Ice, Compression, Elevation) method. Other forms of treatment include taping the ankle or using a brace to restrict movement and to add support and extra stability. Wearing proper footwear is another way that one can prevent and help treat a sprained ankle, as certain shoes are specifically designed to help avoid such injuries. To prevent future ankle sprains, exercises are recommended to help strengthen and stabilize the joint and surrounding ligaments and muscles.

For more information on ankle anatomy and sprains, check out these articles on BOFAS and SPORTS-Health.

Cause and Management of Stretch Marks

Stretch marks. How are they caused? Can they even be treated?

Stretch marks can happen to anyone, of any age, so these questions are important to many. In short, our skin is made up of both collagen and elastin, two elements that support and shape our skin through their natural elasticity. This elasticity, however, does have its limits. And when that breaking point is reached, the collagen and elastin rupture, leaving behind scars many know well – a stretch mark.

Difference between normal skin tissue and stretch mark tissue
From Ud-Din, McGeorge, and Bayat, Journal of the European Academy of Dermatology and Venereology 2015

Stretch marks are caused when skin expands or shrinks at a more rapid pace than the collagen and elastin can accommodate, resulting typically in raised scars that can appear rather inflamed at first. Over time, however, these stretch marks may fade, nearly matching one’s natural skin tone, and usually fall below the surface of the skin. This results in the feeling of a slight indentation when touching older stretch marks.

Like all scars, stretch marks are permanent. But this does not mean that they cannot be treated. There are many treatments available to diminish the visual effect of a stretch mark; not all of them are effective, and some seem not to work at all.

Collagen’s elasticity is controlled by the body’s  cortisone levels, which are commonly associated with episodes of high stress. Basically, heightened cortisone production may decrease the skin elasticity, suggesting that reducing one’s stress may be the most cost-effective and cheap treatment for stretch marks.

Researchers S. Ud-Din, D. McGeorge, and A. Bayat put these post-stretch mark treatments to the test in their paper, focusing on three topical treatment categories – marketed skin creams and oils, over-the-counter home remedies, and prescription medicines and dermatologist procedures.

These topical treatment methods are mainly marketed at increasing collagen production with both hydrating and anti-inflammatory traits. Ultimately, testing yielded mixed results about the efficacy of these treatments. Since participants both massaged their scars and used a topical treatment, the observed improvements to stretch mark appearance could be tied to either of these. Ultimately, however, the researchers did conclude that the age of the scar plays a role in treatment effectiveness, as younger, newer scars were more responsive to treatments.

Beyond these topical treatment methods tested, there are many other dermatological procedures designed to reduce the appearance of stretch marks, including chemical peels, laser therapy, and microdermabrasion. Chemical peels and microdermabrasion focus on removing layers of skin to expose new, non-scarred tissue underneath the stretch mark. And laser therapies are divided into two categories: those that stimulate collagen production and those that promote melanin production (so that the scar tissue matches the natural skin). While these dermatologist procedures can be more effective than the topically applied treatments, they are often expensive and are not guaranteed to be effective. Additionally, dermatologists often combine several procedures, eliminating this treatment for those with cost constraints.

All in all, there are no sure-fire ways to prevent stretch marks, but certain practices do demonstrate that one can prevent stretch marks or at least lessen their appearance fairly cheaply and effectively without any of the products and procedures detailed above. By maintaining a healthy weight, one may avoid the rapid weight loss or gain commonly associated with stretch marks.

For more information, check out these articles on Healthline and AAD.