Speaker- Dr. Todd Schlesinger
Exosomes warranted further exploration due to the ongoing controversy surrounding them. Opinions varied widely, with some praising exosomes for their potential benefits while others dismissed them as ineffective. This prompted a call to delve deeper into the scientific understanding of exosomes. The current regulatory landscape, emphasizing the lack of a clear pathway for exosome-related therapies worldwide.
In the United States and Europe, regulatory bodies primarily focused on the contents of exosomes, with the Food and Drug Administration (FDA) taking a keen interest in this aspect. In contrast, countries like Japan emphasized the methods used to obtain exosomes. In several Asian nations, as well as Europe, regulations prohibit the use of human-derived exosomes, leading to the exploration of alternatives such as rosebud exosomes.
The regulatory landscape of exosome applications in the United States has been indifferent. The desire for companies to achieve Tier-1 status with the FDA. This tier categorized exosomes similarly to cosmetics, while higher tiers moved toward drug classification. The current United States (U.S.) environment remain largely unregulated, with exosomes primarily used topically as cosmeceuticals and no injectable applications permitted. In contrast, countries like Spain had begun using injectable exosomes.
Exosomes are extracellular vesicles, typically around 100 nanometers in diameter, produced by cells for various functions. Some vesicles serve to eliminate waste, while others play roles in apoptosis or signal transmission. Platelets and red blood cells were the primary sources of extracellular vesicles in healthy individuals, whereas macrophages and lymphocytes could produce exosomes in cancer contexts. Concerns remained regarding the implications of administering exosomes to patients, though no significant issues had yet been observed. Additionally, exosomes exhibit specific cell surface markers and had been utilized for characterizing exosomes produced by different companies.
Exosomes have pronounced role as nanoparticles traversing through tissues throughout the body, thereby facilitating communication between cells. Exosomes transmit signals crucial for a wide range of bodily functions. This understanding underscored the pervasive influence of these extracellular vesicles in cellular interactions and overall physiological processes.
Exosomes can be utilized as biomarkers for various conditions, including cardiovascular disease and their possible anti-apoptotic properties, which could promote hair growth. Stem cell-derived exosomes have significant regenerative capabilities, offering advantages over stem cells themselves, such as ease of storage, transmission, and lyophilization. Exosomes can originate from multiple sources, including adipose tissue, platelets, and bone marrow, and consist of a lipid bilayer containing various components like lipids, m-Ribonucleic acids (mRNAs), and deoxyribonucleic acids (DNAs). The ongoing effort to characterize these elements, raises questions about whether the therapeutic effects stem from the lipid contents, the lipid bilayer, or the associated transmembrane proteins. The area has been open to further investigation and speculation.
A recent article published in 2024, presented the latest findings on exosome biology and their production. They explained that particles are internalized by cells through various pathways, leading to a sorting process that results in the formation of microvesicular bodies. These bodies are subsequently transformed into different vesicles, which are excreted via Soluble N-ethylmaleimide-sensitive factor activating protein receptor (SNARE) proteins, known for their role in neuromodulation. The speaker emphasized that once exosomes are released, recipient cells uptake them through multiple pathways, including endocytosis and adhesion molecule interactions. Within the recipient cell, exosomes may either be degraded or participate in processes such as protein synthesis, DNA synthesis, and RNA synthesis. This ongoing molecular investigation aimed to enhance the understanding of exosomes and their functions within cells.
Exosomes, ranging from 30 to 100 nanometers in size, are comparable to most viruses, with many companies identifying 100 nanometers as the optimal size for their applications. They outlined the key differences between stem cells and exosomes, noting that stem cells have received various regulatory approvals for different uses, are often autologous, and are live entities used for treatment. In contrast, exosomes remained unregulated but offered advantages in terms of ease of transmission, storage, and global transport, allowing them to be safely utilized across different regions.
Various purported applications of exosomes in dermatology and described their production methods. They noted that tangential flow filtration had emerged as the preferred technique among companies for generating exosomes, as it was more effective in producing cleaner products compared to ultracentrifugation, which was deemed less efficient. The speaker highlighted the promise of newer immunoaffinity techniques, which allowed for more efficient and cleaner exosome production. Additionally, they mentioned size exclusion chromatography as another commonly used method. They specifically discussed a double tangential flow filtration process utilizing a Polymethyl methacrylate (PMMA) membrane, which effectively sorted exosomes and minimized contaminants, though this method was recognized as costly.
The use of electrospun nanofibers as a method for exosome extraction from conditioned media. This technique involved applying heat and utilizing antibodies to capture exosomes, allowing for their release in a purified form on the other side. Although effective in reducing contamination and enhancing purity, this method was noted to be more expensive. The electrification of the nanofibers contributed to the purification process, making it a promising yet costly option for exosome isolation.
A new technique involving membrane sensing peptides for exosome isolation. The method focused on sensing membrane structures using extracellular proteins to capture and purify exosomes more effectively, making it potentially more feasible for clinical applications. The importance of examining electron micrographs when evaluating a company’s exosomes, as these images reveal the cleanliness, uniformity, and composition of the exosome preparations. The particle size of exosomes produced via membrane isolation was relatively uniform, showing improvements over size exclusion chromatography. Overall, each of these advancements represented progress in exosome purification techniques.
Dual mode chromatography, which utilized both an acidic and electrical cation exchange process alongside traditional chromatography methods. This dual approach aimed to enhance the purification of exosomes by effectively removing unwanted contaminants. They emphasized ongoing laboratory efforts focused on purifying exosomes and their various properties, reinforcing the importance of achieving high-quality preparations. The significance of understanding the sources of contaminants in exosome production remain vital.
A typical tangential flow filtration setup used to purify exosomes from stem cell-conditioned media derived from fat. This process involved multiple filtration rounds to produce a purified exosome product that could be lyophilized, transmitted, and later reconstituted for patient use. They emphasized the importance of observing clean cell surface marker profiles, indicating purity in exosome preparations. The presence of a well-defined double lipid bilayer in the exosomes, showcasing the quality of the product. They also pointed out the successful removal of impurities, such as calnexin and Cytochrome-C, from the supernatant. Spectroscopy results highlight the purity achieved through good manufacturing techniques.
The emerging applications of exosomes in dermatology, particularly for conditions like atopic dermatitis. Evidence indicate that exosomes could help reduce inflammatory cytokines, decrease skin thickening, enhance hydration, and promote ceramide synthesis, suggesting potential benefits in this area. Additionally, a study highlighted the role of exosomes in the anti-aging process, showing reductions in wrinkles, skin roughness, and wrinkle height when human adipose-derived stem cell exosomes were applied. The findings illustrated improvements in skin elasticity and hydration, indicating that topically applied exosomes could address various aging-related skin issues. The exosomes were often used in conjunction with microneedling techniques in clinical practice.
The role of exosomes in addressing pigmentation issues, specifically through the Nuclear factor erythroid 2-related factor 2 (NRF2) pathway, which is implicated in hyperpigmentation conditions like melasma. Adipose-derived stem cell exosomes could upregulate NRF2, potentially leading to decreased pigmentation. Hence, exosomes can treat various skin conditions, including atopic dermatitis, inflammatory conditions, wrinkles, fine lines, pigmentation, and erythema.
Exosomes can be used in treating dupilumab-induced atopic dermatitis, with a reduction in skin redness attributed to topical application of exosomes. Questions can be raised regarding the uniformity and size of exosomes. Platelet-derived exosome products had undergone various studies across different phases of clinical development, indicating a growing body of research in this area. They encouraged attention to the expanding number of studies available.
Exosomes have promising application in promoting hair growth. The emphasis is on importance of WNT proteins in hair follicle development and the Wingless-related integration site (WNT) signaling pathway, along with β-catenin, could be leveraged to encourage hair follicle progression from the telogen phase to the anagen phase. This mechanism was particularly relevant for individuals using smoothing inhibitors for basal cell carcinoma, who often experience hair loss. Case reports indicate significant hair restoration with exosome treatment. Animal models demonstrated that injections of adipose-derived stem cell exosomes led to an increased number of hair follicles and improvements in hair thickness and growth. In these studies, depilated mice treated with adipose-derived stem cell exosomes showed faster hair regrowth and a thicker epidermis compared to controls treated with phosphate-buffered saline. These findings were promising, however further exploration in human subjects remain necessary.
The critical balance between apoptotic and anti-apoptotic factors in hair growth through the treatment reduced apoptotic factors while simultaneously increasing the anti-apoptotic factor B-cell leukemia/lymphoma 2 (BCL-2), effectively shifting the balance toward anti-apoptosis. This alteration was considered particularly promising for enhancing hair follicle activity and regeneration, generating excitement about the potential implications for hair restoration therapies.
A recent 2024 paper focused on the use of exosomes for hair growth and rejuvenation. The study involved manipulating WNT signaling through knockout and overexpression of WNT exosomes, which favoured hair growth. Blue exosomes entering dermal papilla cells, suggesting that the exosomes effectively infiltrated these growth factor-rich cells, which are critical for hair follicle development. A case series demonstrated improvements in hair thickness following exosome injections, and more clinical trials investigating alopecia were ongoing across the country. While various sources of exosomes were available, placing too much emphasis on numerical claims, suggesting that future research would clarify the mechanisms of action, possibly indicating that the lipid bilayer and transmembrane proteins might play significant roles beyond the exosomal contents.
Several challenges associated with exosome use in clinical practice. Ongoing concerns regarding the purity of exosomes and the issue of rapid clearance from the body. The FDA was particularly focused on these concerns, especially regarding the potential accumulation of exosomes in various organs following injection. As they reviewed different companies and their products, these challenges need to be addressed to ensure safe and effective use of exosomes in treatments.
The enhancement of safety and efficacy of exosome injections by combining them with polymers and crosslinkers has been under observation. By integrating exosomes into a gel matrix, this approach could allow for sustained release, preventing rapid clearance and improving therapeutic outcomes. Hence, addressing these questions as exosome science evolved, particularly in areas like drug delivery and genetic modification through Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology. The diverse cell surface markers present on exosomes could offer numerous applications in patient treatment, spanning from drug delivery to organ transplantation.
The significant role of exosomes in drug delivery, emphasized by ongoing research aimed at improving the efficiency of medication delivery to patients. Various methods have been explored for loading drugs into exosomes, reflecting the breadth of inquiry in this area. Numerous studies have been underway in the field, particularly within dermatology, underscoring the wealth of research being conducted globally.
33, European Academy of Dermatology and Venereology Congress, 25-28 September 2024, Amsterdam
