Skin ageing is a biological degenerative process, marked by loss. The number of patients seeking nonsurgical rejuvenation of the face and the body is continuing to increase due to a growing ageing population concerned with physical appearance. Women wish to maintain a youthful appearance and attractiveness represent 92% of all cosmetic procedures.(1) Men are keen to maintain physical characteristics associated with virility.(2) Millennials are also increasingly concerned with preserving their beauty and youth.(3) Among the various treatment approaches, different minimally invasive techniques have been developed and dermal fillers currently come second after botulinum toxin type A (BTA).(3) Their use is increasing worldwide. 

"The fear of looking done is the number 1 reason why patients don't seek treatment"*

​The range of fillers available for soft-tissue augmentation is constantly expanding. The latest advances in filler technology include bio-stimulators that exert their aesthetic effect by promoting predominantly collagenesis or biological stimulation of new collagen and sometimes also elastin production. Therewith they provide a biological answer to the skin ageing degeneration process, with gradual and often very natural results. Over the course of last years the knowledge on injectable bio-stimulators has grown, and therewith their safety and popularity as they provide subtle longer lasting results.

Facial fillers can be broken into 3 main groups:

1. classic dermal fillers (mainly hyaluronic acid-based) 
2. biostimulating fillers
3. bioremodelers (Profhilo) or skin boosters (mainly hyaluronic acid based) improving overall skin quality and hydration

There is evidence that classic dermal fillers stimulate collagen production by stretching of the dermal fibroblasts near the injection side (4). Although classic hyaluron based fillers are still the most popular treatment for soft tissue augmentation, I will focus on bio-stimulators.

Bio-stimulating fillers promote the body’s natural production of some ECM components (mostly collagen) over a period of several months. 
Their differences are characterized by their property of inducing natural collagen production.

SYNTHETIC BIOSTIMULATORS

1. Ceramics, Calcium Hydroxylapatite (CaHA) Radiesse 30% microspheres Merz  or Crystalys Luminera 55.7% microspheres Allergan
2. NEW Mix of Hyaluron filler = CaHa HArmonyCa: Calcium hydroxyapatite microspheres 25-45 microns in diameter (55.7%) cross-linked sodium hyaluronate gel (20 mg/ml), phosphate buffer. Lidocaine hydrochloride (3 mg/ml) Allergan or NEAUVIA stimulate 26 mg/ml Ha crosslinked with PEG = 1% CaHa
3. Poly-L-lactic acid (PLLA) Sculptra 150 mg/vial Galderma or Lanluma V [210 mg /vial] and Lanluma X [630 mg/vial] Sinclair Pharmaceuticals
4. Polymers, polycaprolactone (PCL) Ellansé, 30% microspheres Sinclair ​or GOURI
5. Polydioxanone (PDO) a resorbable, synthetic biocompatible polymer, a material we know from PDO threads - brand Ultra-COL
6. Polymethyl methacrylate (PMMA), Bellafill 20% microspheres in bovine collagen, Suneva Medical - permanent polymer (not recommended)

Besides their different compositions, formulations, product preparations and injection modalities, their main differences consist of their degradation kinetics, level of efficacy and duration of action. The aliphatic polyesters, PCL and PLLA, degrade slowly by hydrolysis of the ester bonds and have a long duration with PCL having the longest. CaHA degrades more rapidly by a different mechanism. 

Calcium Hydroxylapatite
Calcium hydroxylapatite: Calcium hydroxylapatite is a type of mineral that is commonly found in human teeth and bones and in injectbales the calcium hydroxylapatite particles are suspended in a gel-like solution. The effects of this material last approximately 18 months with minimal inflammatory response.
Radiesse is a biodegradable filler consisting of 30% synthetic CaHA microspheres (diameter of 25-45μm) suspended in a 70% aqueous carboxymethylcellulose gel carrier. The soluble carrier gel evenly distributes the Radiesse CaHA microspheres providing 1:1 correction and gradually dissipates leaving the microspheres at the injection site where they induce collagenesis (collagen type I and mostly collagen type III) by fibroblast activation. Animal studies have shown that this new collagen growth occurs as early as four weeks post-injection and continues for at least 12 months with an average duration of effect of 12 to 18 months, though some results have been noted 24 months post-injection. Radiesse provides both immediate (replacement volume) and long-lasting (collagen biostimulation) volume enhancement. (5)

Poly-L-lactic acid
PLLA is a biodegradable, bioresorbable biocompatible man-made polymer. This material has wide uses in absorbable stitches and bone screws. The effects of PLLA generally become increasingly apparent over time (over a period of several weeks) and its effects may last up to 2 years. There is an inflammatory response. PLLA is an alpha hydroxy acid polymer of the lactic acid L-enantiomeric structure that has been safely used in many applications and in medicine for more than 30 years. Its use has expanded worldwide, associated with good long-term aesthetic results thanks to its biostimulatory-collagen effect. PLLA-based fillers are supplied as a lyophilized powder to be reconstituted with sterile water. The collagen stimulatory properties were evidenced in human in subjects (n=14) who received PLLA injections (3 sessions, spaced 4 weeks apart) at the postauricular level by collagen histochemical determination on biopsies taken at different times. Increase of collagen type-I was shown at 3 and 6 months. This study opened the new class of collagen stimulators. The long duration of action was demonstrated in a first pivotal study comparing PLLA versus collagen (116/117 subjects, respectively); the long-term safety/efficacy was shown up to 25 months. The rationale for several sessions was first documented in a dedicated article; this modality allows the effect through collagen stimulation, a biological process to occur and avoids overcorrection. PLLA fillers are among the most clinically documented products. (6)

Polymers, polycaprolactone
The PCL-based collagen stimulator is composed of PCL microspheres suspended in a carboxymethyl-cellulose gel carrier providing immediate and sustained volumizing effects when injected; the morphology, the biocompatibility of the PCL microspheres embedded with the collagen fibers produced all contribute to the creation of a unique 3D scaffold for a sustained effect. Its safety has been investigated in clinical studies and vigilance surveys. It presents the advantage of a slower degradation than polylactic acid (PLLA) or polyglycolic acid (PGA), which both belong to the same chemical family.
Both the S and M products induced collagen production. In animal, the M product induced collagen type-III and type-I at early stage (measure at 9 months), and later predominantly collagen type-I, that deposits around the PCL microspheres (measure at 21 months). Many fibroblasts were found near the PCL microspheres. Interestingly, new elastin fibers were also formed, and neovascularization with new capillaries observed as well. (7)

NATURAL BIOSTIMULATORS

1. Platelet rich plasma
2. Platelet rich fibrin
3. Polynucleotides like Nucleofill or Nucleadyn
4. Exosomes

Platelet-Rich Plasma (PRP): PRP treatments are produced by spinning a small volume of the patient’s own blood through a centrifuge. This separates and concentrates the blood’s components, including platelet-rich plasma and the “buffy coat,” a solution that contains immune cells. The provider combines these two components with a small amount of calcium chloride (which activates and keeps the PRP stable), then injects them into the treatment area. Over a period of months, PRP stimulates the body’s natural collagen production.

Platelet-Rich Fibrin (PRF): PRF is produced using a process similar to PRP concentration. The active material is a fibrin matrix rich in platelets, stem cells, and immune cells. Like PRP, PRF treatment stimulates collagen production and is also implicated in tissue regeneration, though there’s less data on the durability of its effects.

Because both treatments use material from the patient’s own body, so there’s no risk of rejection or similar complications. PRF and PRP effects are durable — typically lasting longer than 18 months.

Polynucleotides: Polynucleotides are most often natural, highly purified DNA molecules extracted for example from trout gonads and activate specialised cells called myofibroblasts and adipocytes. PN containing devices act as short time temporary fillers thanks to the viscoelasticity of the long DNA fragments and improve skin well‐being (cell growth) and steady self‐repair (tissue regeneration). Read more

Exosomes: The use of exosomes at the Aesthetic & Anti-Aging Medicine World Congress in Monaco was discussed during many session and some excellent results were presented. However their use is not yet approved and safety and long-term effect not yet established and largely depends on the source. Read more

BOTULINUM TOXIN 
There is evidence that the neuromodulator or musclerelaxer Botinumtoxin after injection upregulated the expression of type I collagen, decreases the production of some MMPs in fibroblasts, preventing collagen degradation and improves collagen organisation. (8.9.)

ENERGY BASED DEVICES
Intense Pulsed Light/BroadBand Light, Radiofrequency Microneedling, lasers, High-Frequency Ultrasound, Electromagnetic Tec. stimulate collagen production via a controlled damage and repair mechanism.

DERMO-COSMETICS WITH BIO-ACTIVES
There are innovative dermo-cosmetic products containing bio-stimulating ingredients, working more superficial in comparison to in-office treatments and they therefor are potentially an excellent choice as adjunctive care for biological rejuvenation and revitalization for younger looking and acting skin. They are safe to use easy to apply over face, neck and décolletage. Unlike in-office treatments their effects are temporary (fully reversible as regulated), hence they require daily or twice daily application.

Bio-stimulating active ingredients in skincare which have shown to particularly stimulate the fibroblast are for example:

• Creatine (bio-stimulation of collagen I and IV by + 35%  and elastin with +36%) (10)
• Glycine Saponin (bio-stimulation of hyaluron production +256% and collagen +49%) which is also a powerful anti-oxidant (11.12)
• Arctiin (bio-stimulating collagen production + inhibiting of HN-Elastase responsible for collagen & elastin degradation) (10)

A 52 kDa Micro-Hyaluron molecule has proven to be the most potent to bio-stimulate the production of hyaluron by keratinocytes with 209%. (11) Read more about inhibiting hyaluron degradation

VITAMIN C IS NEEDED FOR COLLAGEN SYNTHESES! 
Our skin needs Vitamin C to produce collagen and is not able to produce it, thus relies on external resources for supply. Therefore I highly recommend to either get enough Vitamin C from your diet or use a high quality topical product pre & post biostimulators. Read more

As the biological degeneration takes place in different layers of the skin and it's underlying structures, combining in-office treatments specifically targeting those layers in a series of treatments may provide longer lasting results and give higher patient satisfaction.(13) Safety and outcome rely on the qualification and experience of your cosmetic doctor, dermatologist or plastic surgeon. 


Take care


​Special thanks 
MD FAAD Hassan Galadari 
Jair Mauricio Cerón Bohórquez M.D.

References:
1. American Society Plastic Surgeons. 2020 national plastic surgery statistics; 2020. 
2. Wat H, Wu DC, Goldman MP. Noninvasive body contouring: a male perspective. Dermatol Clin. 2018;36(1):49–55. 
3. Wang JV, Akintilo L, Geronemus RG. Growth of cosmetic procedures in millennials: a 4.5-year clinical review. J Cosmet Dermatol. 2020;19(12):3210–3212. 
4. Evaluation of the biostimulatory effects and the level of neocollagenesis of dermal fillers: a review. Haddad S, Galadari H, Patil A, Goldust M, Al Salam S, Guida S International Journal of Dermatology, 29 Apr 2022
5. J Clin Aesthet Dermatol. 2015 Jan; 8(1): 38–49. Calcium Hydroxylapatite Over a Decade of Clinical Experience Jani Van Loghem, MD, Yana Alexandrovna Yutskovskaya, MD,b and WM. Philip Werschler, MDc
6. Clin Cosmet Investig Dermatol. 2022; 15: 997–1019. Collagen Stimulators in Body Applications: A Review Focused on Poly-L-Lactic Acid (PLLA)
Marie-Odile Christen Read more
7. Clin Cosmet Investig Dermatol. 2020; 13: 31–48. Polycaprolactone: How a Well-Known and Futuristic Polymer Has Become an Innovative Collagen-Stimulator in Esthetics Marie-Odile Christen and Franco Vercesi
8. Oh SH, Lee Y, Seo YJ, Lee JH, Yang JD, Chung HY, Cho BC. The potential effect of botulinum toxin type A on human dermal fibroblasts: an in vitro study. Dermatol Surg. 2012 Oct;38(10):1689-94. 
9. El-Domyati M, Attia SK, El-Sawy AE, Moftah NH, Nasif GA, Medhat W, Marwan B. The use of Botulinum toxin-a injection for facial wrinkles: a histological and immunohistochemical evaluation. J Cosmet Dermatol. 2015 Jun;14(2):140-4​
10 EADV 2022 Inhibition of extracellular matrix degrading enzymes and bio-stimulation of fibroblasts – A novel approach to mitigate the advanced degenerative process in skin aging Weise J, Vogelsang A, Sperling G, Welge V, Nölter A, Mielke H, Knott A, Harbig S, Stuhr A, Dunckel J, Warnke K, Geloven van A
11. EADV 2021 Multifaceted novel approach to increase skin’s own epidermal and dermal hyaluron content Bussmann T, Warnke K, Krüger A, Möller N, Harbig S, Stuhr A, Dunckel J, Geloven van A, Weise J | Beiersdorf AG, Hamburg, Germany
12. Photochemistry and Photobiology, 2005, 81: 581–587 Novel Aspects of Intrinsic and Extrinsic Aging of Human Skin: Beneficial Effects of Soy Extract Kirstin M. Su¨del et al
13. Combination Therapy in Midfacial Rejuvenation Humphrey et al. Dermatologic Surgery 42:p S83-S88, May 2016. 
*AMWC 2023 Tapan Patel

Polynucleotides (PNs) are a type of biomolecule that have recently gained traction in the field of skin care and aesthetic treatments. PNs are composed of multiple nucleotides, which are the building blocks of DNA and RNA. These biomolecules have shown promise in improving the appearance and health of the skin through their ability to stimulate cell growth (activate growth factors), tissue regeneration incl. collagen production, wound healing, fibroblast proliferation and have anti-inflammatory properties.

Polynucleotides (PN) are linear polymers composed of many nucleotide units and they play a key role in the storage and transmission of genetic information. There are two types of polynucleotides (aka nucleic acid) found in nature: ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). As mentioned, PN are composed of nucleotides, which consist of 3 parts: a nitrogenous base, a phosphate group. and a five-carbon sugar (2'-deoxyribose in DNA or ribose in RNA). The five base nucleotides are adenine, guanine, cytosine, thymine, and uracil. A DNA molecule consists of two long polynucleotide chains composed of four types of nucleotide subunits: adenine, thymine, guanine, and cytosine, while RNA uses adenine, guanine, cytosine and uracil. 

REGENERATIVE AESTHETICS

Regenerative aesthetics is an emerging branch of regenerative medicine with therapies or products aimed at recapturing youthful structure and function using the body's own systems. Examples of such treatments are platelet-rich plasma (PRP), the use of exosomes or polynucleotides.
Dr. Kate Goldie explained soft tissue regeneration fundamentals as following: 
1. Regeneration of tissue architecture (structure): tissue composition - component abundance, ratio's, position, density and biomechanics/integrity
2. Regeneration of tissue function: signaling, cell function, cellular components (incl. senescence), gene expression and molecular interaction.
The 3 treatment pillars of regenerative aesthetics are: cells, biocues and bio-stimulatory scaffolds. Key superficial soft quiescent cells are the fibroblasts and adipose derived stem cells. One of the big advantages of regenerative aesthetics is by using the body's own system, the results are natural and focused on "skin health" (function) and "skin quality" (appearance).

POLYNUCLEOTIDES IN REGENERATIVE AESTHETICS

Polynucleotides are most often natural, highly purified DNA molecules extracted for example from trout gonads and activate specialised cells called myofibroblasts and adipocytes. PN containing devices act as short time temporary fillers thanks to the viscoelasticity of the long DNA fragments and improve skin well‐being (cell growth) and steady self‐repair (tissue regeneration). Studies support their dermal reactivating properties or their efficacy as “bioreactivating primers” of skin. The final outcome is more natural and in‐depth tissue regeneration and a healthier look of the skin: a more radiant complexion, even skin tone, reduced appearance of fine lines, wrinkles and sagging, faster wound healing, improved pore size and skin thickness, elasticity and hydration. Furthermore, PNs are generally well-tolerated by the skin and have a low risk of adverse effects. Their effectiveness may vary depending on the individual's skin type, age, and overall health. The long-term effects of PNs on the skin are not yet fully understood, and more research is needed to determine their safety and efficacy. There are various brands available which use polynucleotides in their (meso-) injection gels. For example Mastelli Srl, Italy NEWEST® (Polynucleotide and Hyaluronic Acid) for bio-revitalization, BR Pharm HP Cell Vitaran Skin Healers, NUCLEADYN® or Nucleofill®.

One brand of (synthetic) polynucleotide-based skin care products is Yuva by Dr. Devgan Scientific Beauty. The Yuva line includes a range of products formulated with PNs, such as the Yuva Serum and the Yuva Enhancer. These products are marketed as being able to provide hydrating, anti-aging, and skin-rejuvenating benefits.

THE FUTURE OF POLYNUCLEOTIDES

While polynucleotides have many benefits, they also have some drawbacks. One of the primary limitations is their instability in certain environments. This instability can make it difficult to synthesize and manipulate polynucleotides in the lab. Moreover their are limitations, risks and ethical concerns harvesting or using (human identical) PN's, and long-term safety and efficacy data is not conclusive. However, PNs are a promising area of research in the field of skin care and aesthetic treatments and regeneration. We can expect to see further advancements in the development of PNs-based products and treatments. PNs are already used in combination with other biomolecules, such as hyaluronic acid, growth factors and anti-oxidants and used in combination with other treatments. For a personal recommendation on which aesthetic treatment is most suitable to aesthetically regenerate your skin, please consult an experienced board certified dermatologist, plastic surgeon or cosmetic doctor. 

Take care.

Glycation is one of the basic root causes of endogeneous (intrinsic) skin ageing and a very challenging one or almost impossible one to reverse. Glycation is an ageing reaction which begins in early life, developing clinical symptoms at around 30, and progressively accumulates in tissues and skin due to the glycated collagens that are difficult to be decomposed. Glycation occurs naturally in the body when sugars react with proteins and lipids to form advanced glycation end products (AGEs). AGEs can be exogenously ingested (through food consumption), inhaled via tobacco or endogenously produced and formed both intracellularly and extracellularly. AGE modifications lead to dermal stiffening, diminished contractile capacity of dermal fibroblasts, lack of elasticity in the connective tissues, contribute to hyperpigmentation and a yellowish skin appearance. The formation of AGEs is amplified through exogenous factors, e.g., ultraviolet radiation. 

AGEs cause changes in the skin through 3 processes:

1. AGEs interact with specific cell receptors, altering the levels of soluble signaling molecules, such as cytokines, hormones, and free radicals.
2. In the process of non-enzymatic glycation reaction, a large number of reactive oxygen radicals are released, creating a state of oxidative stress, leading to a significantly reduced level of glutathione, Vitamin C, and Vitamin E in the body. This causes synthetic disorders of collagen in skin tissues. 
3. AGEs alter the physical and biological properties of the original extracellular matrix proteins, such as collagen. 

Many cells have AGEs receptors on the surface, such as macrophages, mesangial cells, fibroblasts, and endothelial cells, through which their function can be affected. They induce oxidative stress and trigger inflammatory pathways by forming crosslinks, altering protein structure, or by binding to AGEs receptors. AGEs cause cellular dysfunction through the modification of intracellular molecules and accumulate in tissues with ageing. This causes the skin and connective tissue to harden and lose their ability to regenerate healthy cells. They cause damage to extracellular proteins like collagen and elastin fibers, which are crucial for maintaining skin structure and firmness. This damage leads to the breakdown of these fibers. AGEs can also affect intracellular proteins like vimentin. AGEs can act as a catalytic site for free radical formation, exacerbate intracellular oxidative stress, and increase ROS production through a variety of mechanisms, reducing glutathione (skin's own anti-oxidant) storage, and activation of protein kinase C, etc., to accelerate the production and accumulation of AGEs. 

One study published in the Journal of Investigative Dermatology found that levels of AGEs were higher in the skin of older individuals compared to younger ones. The study also showed that there was a correlation between the level of AGEs and the severity of skin ageing. This suggests that inhibiting the production or accumulation of AGEs in the skin is a potential target for anti-ageing interventions or skin ageing management.

AGEs are complex and heterogeneous, more than a dozen AGEs have been detected (however not all) in tissues and can be divided into three categories according to their biochemical properties. 
​AGEs are formed through four pathways:

1. the Maillard reaction (non enzymatic reaction between amino groups of proteins and reducing sugars, binding sugars to proteins)
2. sugars auto-oxidation pathway (metal-catalyzed auto-oxidation of glucose or Wolff pathway) 
3. lipid peroxidation pathway (acetyl alcohol pathway)
4. polyols pathway (glucose is converted into fructose via the polyol pathway, which accelerates the production of AGEs)

GLYCATION INHIBITION IS KEY 
AGEs can be crosslinked through side chains to form a substance of very high molecular weight, which is not easily degraded. The consequences from skin glycation are irreversible. This makes prevention or inhibition of the process the best potential strategy to maintain skin health and ageing skin management. One way to do this is by altering the diet to reduce the intake of sugars and carbohydrates, which are known to contribute to glycation. Several studies have found that reducing sugar intake can result in significant improvements in skin health, including reducing wrinkles and improving skin texture. 

AGE inhibitors
Another potential strategy is the use of topical agents that inhibit the formation or accumulation of AGEs in the skin. One study published in the Journal of Cosmetic Science found that a cream containing carnosine, a peptide that inhibits glycation, improved skin elasticity and reduced the appearance of wrinkles in individuals with ageing skin. Skincare containing NAHP or Acetyl Hydroxyproline inhibits the formation of AGEs significantly (in vitro), most likely through a mechanism where NAHP competes with the proteins for the sugar. Finally, NAHP sacrifices itself in place of the proteins and gets (at least partially) glycated. NAHP also prevents loss of cellular contractile forces in a glycated in vitro dermis model and counteracts the diminished cell-matrix interaction that is caused by glyoxal-induced AGE formation.

​Anti-Oxidants
Moreover, I would suggest to combine those ingredients with an ingredient like Licochalcone A. Numerous high ranked publications support that Licochalcone A protects cells from oxidative stress mediated by e.g. UV and HEVIS (blue light) induced reactive oxidative species (ROS). Due to the activation and nuclear translocation of the transcription factor NrF2, the expression of anti-inflammatory, antioxidant and detoxifying enzymes are induced. These enzymes protect the skin cells (like keratinocytes and fibroblasts) from ROS-induced damage, like lipid peroxidation and DNA as well as protein damage. If Licochalcone A is combined with L-Ascorbic Acid, (the most active form of Vitamin C), it supporting skin's own collagen production, provides superior biological cell protection amongst other relevant benefits. My absolute favourite product is Eucerin Hyaluron-Filler Vitamin C Booster which I use daily as a serum in my morning routine.

GLYCATION AND SKIN HEALTH

Acne
In addition to its role in ageing, glycation in the skin has also been linked to a range of skin health problems. One study published in the Journal of Cosmetic Dermatology found that the level of AGEs in the skin was significantly higher in individuals with acne than in those without acne. The study also showed that treating acne with a topical antibiotic significantly reduced the levels of AGEs in the skin.

Atopic Dermatitis
Another study published in the Journal of Investigative Dermatology found that individuals with atopic dermatitis had higher levels of AGEs in their skin than healthy individuals. This suggests that glycation may play a role in the development of inflammatory skin conditions.

Diabetes + Woundhealing
The correlation between high sugar levels and skin ageing can be seen in diabetic patients, where one-third of this population has skin complications. A prominent feature of ageing human skin is the fragmentation of collagen fibers, which severely damages the structural integrity and mechanical properties of the skin. Elevated levels of MMP-1 and MMP-2 and higher crosslinked collagen in the dermis of diabetic skin lead to the accumulation of fragmented and crosslinked collagen, thereby impairing the structural integrity and mechanical properties of dermal collagen in diabetes. Collagen crosslinking makes it impossible for them to easily repair, resulting in reduced skin elasticity and wrinkles. Keratinocytes and fibroblasts are the main cells involved in wound healing, but due to the high glucose (HG) microenvironment in diabetics, the functional state of these cells is impaired, thereby accelerating cellular senescence (programmed cell death).

Conclusion
We can't completely stop the glycation process, therefore it's important that we inhibit it from a young age onwards, hence monitor the sugar intake of our children, use daily SPF and invest in good dermo-cosmetic products containing ingredients like NAHP and powerful anti-oxidants like L-Ascorbid Acid (Vitamin C is needed for the production of collagen) and Licochalcone A (also anti-inflammatory). Preventing signs of ageing, specifically caused by glycation is most effective. If your skin shows (advanced) signs of ageing, you can get visible improvement using skin component (hyaluron, collagen and elastin) bio-stimulating ingredients like Retinol, Bakuchiol, Arctiin, Creatine or Glycine Saponin. Consult your dermatologist if you wish to improve your skin's appearance or skin health issues.

Take care

Special thanks: Ph.D. dr Julia M. Weise Manager Biological Testing & Dorothea Schweiger Lab Manager Facial Skin Biology Beiersdorf HQ Hamburg

Skin boosters using micro-injections with predominantly non-crosslinked hyaluron filler gels like Restylane® Vital, Juvéderm® VOLITE or Belotero® Revive are gaining popularity for very good reasons. Unlike traditional dermal fillers, they are not injected beneath the skin to volumise or shape the face. Instead, they are very fine dermal easily integrated "fillers" that are injected into the skin to hydrate, improve skin quality and give very natural results. They are also gently bio-stimulating, meaning they "stretch" the fibroblasts in the injected area and as a result this cell is producing more collagen. An effective bio-remodeling skin booster using 2 times 5 injection points (bio-aesthetic points - BAP) for a full-face treatment is Profhilo®. However, the recent K-beauty treatment via topical application or micro-injections with bio-remodeling exosomes is gaining popularity.

Exosomes are nano-sized cargos with a lipid bilayer structure carrying diverse biomolecules including lipids, proteins, and nucleic acids. These small extra cellular vesicles are secreted by most types of cells (skin relevant are the keratinocytes and fibroblasts) to communicate with each other. Exosomes circulate through bodily fluids and can transfer information. ​They can be either good or bad, however taken from a healthy young cell they will be sending the best messages. Studies have shown the efficacy of exosomes in skin ageing. They can facilitate skin remodeling (increasing collagen and decreasing senescent cells) leading to skin rejuvenation.

Cells sleep because they don't get enough bio-stimulation: messages. Better messages is better skin architecture. This is why exosomes are so important. At the World Stem Cell Summit it used to be 90% about stem cells (they only life 28 days) and 10% about exosomes, now it is 50/50. The reason is called heterochronic parabiosis. 1. One of the most robust methods of improving the function of ageing tissues is that of heterochronic parabiosis,. The effect was shown in a study with a surgical procedure whereby a young and old mouse are joined together so the share one circulatory system. 2 This study according to dr Kate Goldie AMWC 2023 Monaco is proof that it is not the cells, but the messages they give that is transforming lots of different tissues, which has the ability to profoundly regenerate tissues. That is why people are so interested in exosomes. Exosomes taken from a very young cell give potentially the best messages as they "send the message" of youth. EV (Extra-cellular Vesicle) is the actual correct term as messages come as micro-vesicles and exosomes and form 2 different messages from the cell. 3 We start to understand active ingredients. In exosomes one of the most important ingredients is RNA and is part of the future of regenerative aesthetics. Messenger RNAs up-regulate and Micro-RNAs down-regulate. They physically go into the cell and change how the cells works. So we have to be cautious. In this study "The therapeutic and commercial landscape of stem cell vesicles in regenerative dermatology" dr Kate Goldie et al. assessed all available exosomes in the (UK) market.

Most exosomes used in-office are extracted from human stem cells and frozen to keep them as stable. Unlike actual stem cells, exosomes don't have a nucleus and therefore they are safe to use. Exosome therapy is the application of topical exosomes after in-office treatments which disrupt the skin barrier, like laser resurfacing, chemical peelings or microneedling. Exosomes are also used in micro-injections as a stand-alone skin boosting treatment and in a few skin care products. Be aware that as usual, not all products are alike. The way exosomes are sourced (origin), size, their content (can be growth factors) and function determine largely their efficacy and the price of the product. 

One of the challenges is that we do not really know what is in the exosomes. They are like small packages with a lot of messengers. The use of exosomes looks promising for several indications: regenerative aesthetic medicine, healing, scar treatment, burns and atopic dermatitis, however their safety is not yet fully established and no official registration for their use granted.



​Take care

1. Cell Cycle. 2012 Jun 15; 11(12): 2260–2267. Heterochronic parabiosis for the study of the effects of aging on stem cells and their niches
Irina M. Conboy 
2. Heterochronic parabiosis reprograms the mouse brain transcriptome by shifting aging signatures in multiple cell types Methodios Ximerakis
3. J Cell Biol. 2013 Feb 18; 200(4): 373–383. Extracellular vesicles: Exosomes, microvesicles, and friends Graça Raposo et al

The fibroblast is one of the most important cells involved in ageing skin. You can find it in the lower layer of the epidermis and the dermis. It has many functions, one of which is the production of key components like hyaluron (filling + hydration), collagen (strength + structure) and elastin (flexibility + stretch). It particularly has to work hard to replenish hyaluronic acid or hyaluron as this filling component only has a half-life in the skin of several hours up to a day. Good quality collagen can last 15 years and elastin up to 70 years. It is also believed to be involved in the clean-up of dysfunctional components, like for example broken elastin, which is visible photodamage-damage and called solar elastosis. Fibroblast senescence (agedness) does also increase the risk of age spots. In proper ageing skin management, the fibroblast is a key target-cell.
 
Many aesthetic in-office treatments like ultrasound, radio-frequency, chemical peelings, laser etc. are based on causing controlled damage to the skin provoking wound-healing. This is the base of their rejuvenating or aesthetic impact. The number of new fibroblasts (myofibroblasts) is increased during the wound-healing process. Some injectables, like for example hyaluron-fillers cause the fibroblasts at the injection site to stretch and bio-stimulate collagen production. There are specific bio-stimulating injectable treatments. The most popular ones are Sculptra®, Radiesse®, Ellanse®, and a new one which combines hyaluron-filling and bio-stimulation is HArmonyCa®.
 
As we age the fibroblast is undergoing some changes because of intrinsic and extrinsic factors. It loses it’s production power, it flattens, loses mechanical tension and therewith the ability to interact with other cells in the skin. It is becoming “tired and deaf”. My hypothesis was that injecting large droplets of hyaluron into the dermis might cause the fibroblast to become “lazy” via a negative feedback mechanism: when something is present in abundance, the fibroblast might not be stimulated enough to work hard to replenish it. This is not yet scientifically proven.
 
It is important to keep the fibroblast in good shape and biologically active. We can stimulate it’s biological activity with skincare containing bio-stimulators, or ingredients which activate the production of important skin components by the fibroblast. On the other side we need to protect the cell from damage.
 
Bio-stimulating active ingredients in skincare which have shown to particularly stimulate the fibroblast* are for example:

• Creatine (bio-stimulation of collagen I and IV by + 35%  and elastin with +36%)
• Glycine Saponin (bio-stimulation of hyaluron production +256% and collagen +49%) which is also a powerful anti-oxidant
• Arctiin (bio-stimulating collagen production)

Protection from photo-damage we can achieve with a combination of sunscreen and anti-oxidants, more specifically Licochalcone A. Licochalcone A has a proven broad ability to protect the skin from damaging free-radicals or oxidative stress from UVA, UVB and HEVIS (High Energy Visible Light) affecting keratinocytes and fibroblasts.

I am not yet aware of skincare ingredients which increase the number of (new) fibroblasts, like the semi or minimal invasive in-office treatments. It’s an interesting field to explore if this is possible without injury, inflammation or irritation. However, you probably get "more bang for your buck" by starting a a skincare routine with focus on bio-stimulation and protection of the fibroblast pre- and post minimal and semi invasive aesthetic treatments. This could be something we will proof with a clinical study.

Take care
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*in vitro