After observing the great potential of regenerative medicine in treating various diseases we wanted to use it in our project this year, but then we realized the challenges associated with regenerative medicine like lacking sensitivity and specificity. This led us to the idea of integrating Synthetic biology and regenerative medicine to fill in the gaps found within regenerative medicine and enhance its potential for better tissue regeneration.
After that, we had to identify a problem to apply our approach on, until we encountered patients with burn injuries whose suffering doesn’t end at the time of injury but extends beyond that on various aspects (physically, mentally, and socially) due to the skin disfigurement caused by the burn which results in a stigmatized, depressed, and introverted patient who is unable to engage in daily activities due to scars on their joints causing mobility affection in addition to decreased work productivity and increased financial burden as the costs of their treatment are quite high but not cost effective.
After speaking with several experts like plastic surgery doctors who guided us through the burden of burn beginning from the first aid measures and ending by management of complications especially the scars, the possibility of “scarless wound healing” through combining regenerative medicine and synthetic biology popped up in our minds.
Burns have severe consequences on various aspects of a person's life, including their education, social life, and psychological well-being. This leads to suffering from physical limitations, fear of judgment, and social isolation, in addition to reducing their work productivity. Additionally, burn injuries often require extensive medical treatment, including surgeries, rehabilitation, and long-term care; causing huge burdens for individuals and their families. These economic burdens include healthcare costs, lost productivity due to disability or unemployment, and the expenses associated with rehabilitation and long-term care. These costs, straining healthcare systems' resources and affecting national economies.(1)
Even though burns cause approximately 180,000 deaths worldwide annually in addition to being one of the main causes of daily losses in low- and middle-income countries (LMICs) (2), most of them are not lethal but is quite common everywhere for instance, in 2004, burns were the most common cause of loss globally, accounting for 17% of daily loss in adults aged 15 to 59.(1)
An estimated 11 million people worldwide suffered burns severe enough to require medical attention in 2004; it is ranked fourth among all injuries, behind falls, traffic accidents, and interpersonal violence. Its incidence is higher than that of HIV infections and tuberculosis combined, and only marginally lower than the incidence of all malignant neoplasms worldwide.(1)
Non-fatal childhood injuries are caused by burns that do not exceed 20% of the total body surface area, which affect 153 out of every 100,000 children less than 15 years old. (1)
In Egypt most burns were of domestic type, especially while cooking due to fire use. Moreover, unemployed patients were the majority of victims, about 67.2%. Of those, 31% were below school age and 25% were students, 41% were housewives and 3.2% were retired. The students face educational hardships because of their psychological state which in return affects their concentration, memory, and cognitive function. Similarly, among the unemployed victims, especially the housewives whose injury might be related to the unsafe cooking stoves and to the open fire cooking. Surely, burn took away these females’ beauty and stripped their self-confidence.(3)
Burn is defined as a type of tissue injury (coagulative necrosis) caused by skin contact with a heat source which can be due to high temperature, electricity, chemicals or radiation which leads to loss of skin integrity and functions.(4)
Burn injury area is divided according to the degree of injury into 3 zones including :
Once the skin is injured, it leads to denaturation of cellular proteins which exceeds the capacity of cellular repair. The cellular destruction leads to recruitment of various immune cells, most importantly neutrophils macrophages, monocytes and mast cells where these cells release different inflammatory mediators such as MMPs, TNF-α, IL-8, and IL-10 in addition to growth factors such as VEGF, PDGF, G-CSF and FGF. Even more, the cellular degradation leads to a hypermetabolic state in which the release of reactive oxygen species(ROS) from dead tissues (dead neutrophils), along the inflammatory mediators, causes endothelial cell dysfunction, high vascular permeability which causes tissue edema and hypovolemia. Finally, a microvascular thrombosis is formed due to the clotting factors released, resulting in impairment of tissue healing and greater destruction.(6)
These complications occur due to the increased vascular permeability that causes decreased tissue perfusion in addition to accumulation of ROS from cellular degradation and oxidative stress.
The effect of these burns is limited to the outer layer of the skin, which is called the epidermis. The burn area is red, painful, and dry and has no blisters, with a mild change in the skin color.(8)
This class of burns often involves the epidermis and a part of the deeper layer of the skin called the dermis. The burn area appears red, blistered and may be swollen and painful.(8)
This degree destroys the epidermis, dermis and may reach the innermost layer of the skin which is the subcutaneous tissue. The burn area may look white or black and charred.(8)
These burns destroys all layers of the skin and underlying tissue as well as deeper tissue, sometimes reaching muscles and bones. The nerve endings are also destroys which causes absence of sensation in the burn area.(8)
According to WHO There are general common procedures for burn management before moving to the specific management of each degree.
Typically, first-degree burns result from prolonged sun exposure. They are medically treated through application of topical moisturizers, oral analgesics and prevention precautions.(9)
Second-degree burns’ treatment involves intact blisters debridement to remove the fluid, which contains high concentrations of thromboxane, under coverage of topical antimicrobial agents or synthetic wound dressings. Other deeper elements of the skin remain intact and can regenerate the epithelial layer.(8)
Third-degree burns are characterized by full thickness skin loss, which depends on the amount of body surface affection. Its treatment includes debridement, skin grafting, surgical reconstruction and post-burn rehabilitation.(8)
Fourth-degree burns treatment is the same as third degree burn but the injury might be too severe resulting in amputation and permanent disability.(8)
although these management lines are effective they are limited in various ways causing complications like:
They aim to develop multifunctional wound dressing utilizing synthetic yeasts, with a primary focus on addressing the care of bedsores. The innovative bio-tech bandages are crafted using synthetic yeasts S.cerevisiae, designed to provide three essential core functions. Firstly, the bandages monitor wound healing by tracking changes in oxygen concentration levels. This is crucial as the oxygen concentration in a wound fluctuates based on its healing state, with increased oxygen consumption in the wound area indicating a normal oxygen state in a healed wound and a hypoxic state in a non-healed wound. Secondly, the bandages work to prevent bacterial infections by secreting antimicrobial peptides such as Defensins. This proactive approach helps reduce the risk of infections that can impede the healing process. Lastly, the bandages are equipped to detect bacterial infections by monitoring intercellular communication signals, allowing for early intervention and targeted treatment. By offering these three key functions, YEAST-AID aims to empower non-professionals to effectively and easily facilitate the healing of pressure ulcers, ultimately improving patient outcomes and quality of care.
In the pursuit of addressing scarless wound healing, prior research has explored innovative methodologies. One approach, called TecTissue, combines a multi-glycopeptide scaffold with the recombinant growth factor Leptin B to stimulate fibroblast proliferation—a key step in wound healing. Nanoencapsulation techniques were used to ensure precise delivery of these therapeutic agents. In a simulated setting, TecTissue demonstrated potential in enhancing tissue regeneration while reducing infection risks.
Another new approach addresses a solution for wound healing by bio- synthesizing spider silk from spidroins, spider silk proteins, using modified Escherichia coli. After purifying the protein, it will be spun into a thread, bundled into an amorphous tissue of spider silk, and bound with a layer of collagen. The modified spider silk promotes wound healing and is applied directly to the affected area after cleansing and disinfecting. The patch improves wound healing by sustaining a moist wound environment, decreasing the inflammation, granulation, and increasing the rate of regenerative phases.
As the current treatment approaches for burn are not quite effective and not to mention the complications that can accompany them like scarring, the motivation for new approaches was established in order to deal with burn and provide less complications, one of these new approaches is (Regenerative medicine) which is an evolving branch of medicine aiming at replacing and repairing the damaged tissue within the body to restore the original tissue function which was lost due to trauma or disease or even a congenital defect.(10)
Although still under research, regenerative medicine poses a great potential in the treatment of burn due to its various successful therapeutic applications whether cell based therapy like carticel for cartilage repair and Apligraf for skin regeneration or growth factors like Regranex for diabetic ulcers, all of which were approved by FDA, this encourages scientists to explore the possibility of other therapeutic approaches via regenerative medicine. (11)
In our case we chose regenerative medicine for burn treatment for the possibility of Scarless wound healing which prevents the consequent psychiatric and physical complications associated with the injury.
Due to its promising results in recent years, stem cell therapy has become an advanced and trending scientific research topic by the scientists and now it is considered the cornerstone of regenerative medicine.(12)
Stem cell based therapy is a rapidly evolving branch of regenerative medicine which uses unspecialized cells (stem cells) that have the ability to differentiate into several cell lines within the human body in addition to its capabilities of self-renewal, these cells are of various types where they can be classified according to their origin into adult stem cells, embryonic stem cells and induced pluripotent stem cells or they can be classified based on their differentiation potential into (Totipotent - pluripotent- multipotent - oligopotent - unipotent).(12)
Of all the types of stem cells, mesenchymal stem cells was the best choice to be used in our project for numerous reasons including its multiple sources to be obtained from, their capability of differentiation into multiple different cells, their immunoregulatory properties as it does neither induce immune reaction nor there is need for immunosuppression post administration in addition to their migration and homing for the site of injury causing enhanced therapeutic effects.(13)(14)
Despite the great potential found within stem cell therapy and especially the MSCs, there are various obstacles limiting the usage, the first problem is the risk of tumor formation due to uncontrolled proliferative activity of the cells,the second one is MSC’s cellular senescence which is a cellular response characterized by a stable cell cycle arrest that limits the proliferative potential of cells. This phenomenon depends on various properties like the Cell passages and culture conditions in vitro which impairs all functions of MSCs (proliferation, immunoregulation etc..), the last problem is the short half life of MSCs causing a limited therapeutic effect.(13)(14)
This year our main mission is scarless wound healing done by our approach SONG-H (Stem Cell-based Occlusive Nutritive Gel of Healing) which is a modular platform that enhances the burn wound healing process through a safe, effective, non-dose dependent and non-invasive approach resulting in tissue regeneration without a scar unlike tissue repair and current approaches of burn treatment which leaves markable scars behind resulting in both psychological and physical complications.
| Comparison | Wound Repair | Wound Regeneration |
|---|---|---|
| Description | Patching rather than restoring, replacing the damaged tissue with fibrous connective tissue. (Less functional and less aesthetic) | Cells and tissues are grown to replace lost structures with restoration of normal architecture. (Restore Both function and appearance) |
| Time | The onset of the damage lasts up to 4 weeks. | At the onset of the damage. |
| Cells | Fibroblast and inflammatory cells like MQ and neutrophils. | MSCs (cell-based therapy) which differentiate into specific cells needed to rebuild the damaged tissue. |
| Outcome | Scar formation (Keloid, Hypertrophic scar) | Complete tissue replacement |
| Done By | Normal physiological response | SONG-H |
(1) leverage the regenerative potential of mesenchymal stem cells (MSCs) through expression of a regenerative protein called yes associated protein (YAP-1)
(2) Inducing the proliferation of viable cells within the wound via the exosome delivery system within the MSCs transferring mRNA encoding YAP-1.
Our first goal was achieved by increasing endogenous YAP-1 expression through ligand-specific receptor (dCas9(N/C) Syn VEGFR-1\2) activation. This receptor senses a specific tissue injury biomarker called vascular endothelial growth factor (VEGF) which increases in the microenvironment during burn injury(15). Then eventually, the activation of the receptor causes release of dCas9(transcription modulator) and reassembly of its N&C domains causing it to reach the YAP-1 encoding region by the help of gRNA causing increased transcription,and therefore, increasing the proliferative capacity of our MSCs.(16)
The second goal was achieved by utilizing the MSCs cell signaling ability through exosomes which we loaded with our Translation Initiation Device (TID) (it is an mRNA switch encoding YAP-1 expression) and their delivery to the surrounding viable cells where the switch is specific to MMP-9 (intracellular marker of tissue injury)(17). When MMP-9 is present it causes the TID to be activated through taking a circular form resulting in increased translation of YAP-1 and therefore enhanced proliferation of the viable keratinocytes and better wound healing.(18)
Since we chose to use MSCs in our project this year, the first thing we had to do was to overcome the 3 limitations associated with their use in order to freely use them within our platform SONG-H.
Although our target in this approach was to increase the expression of YAP-1 into both MSCs and viable cells within the wound, We couldn't just leave it to be overexpressed, thus the control of both the receptor and the switch where they are activated only when VEGF and MMP-9 are present( with certain concentrations) during injury respectively. This prevents the risk of uncontrolled proliferative activity of MSCs and provides better therapeutic results.
In order to ensure effective delivery of MSCs to the wound, we utilized a topical hydrogel scaffold. Using the scaffold provided a nutritive media for MSCs ensuring longer half-life of MSCs resulting in better therapeutic effect,in addition to that using hydrogel evades the MSC’s cellular senescence event as the Hyaluronic acid hydrogel simulates the physiological media required for the MSCs functionality therefore providing control over proliferation and better wound regeneration.(19)
Although the use of hydrogels in our approach is of great potential, there are various risks or limitations within its use, one of which is the burst release that is a phenomenon characterized by rapid release of large amount of the encapsulated drug on exposure of hydrogel to the wound environment resulting in shortening of the therapeutic effect of the drug in addition to toxicity potential.(20)
By analyzing the market stakeholders, deep-burned patients settled to be the top target. SONG-H aims to fill the gap of the unmet needs of other burn products in the market. It assists in the healing process and decreases the contractures, muscle wasting, and resulting inabilities.
We aimed to study market competitors, customers’ needs, and environmental factors and gather the best plan for market penetration. Furthermore, we prepared a full entrepreneurship model that helped us study our product and know our position among the competitors.
In our long-term plans, SONG-H will be designed to approach all body cells, specifically ones that aren’t capable of dividing as those of heart, neurons, and joints.
SONG-H is a therapeutic platform which integrates synthetic biology and regenerative medicine concepts. While taking into account safety regulations, it simply uses the innate function of MSCs meanwhile delivering a regenerative protein called YAP-1. SONG-H is introduced in the form of a hydrogel topical scaffold which mainly purpose scars either disfiguring or mobility limiting.
We were inspired by the gap in managing scars and noticed the aim of current treatment which focuses on treating burn not its consequences. Reflectively, this led us to direct our efforts towards second and third degree burns, causing massive scar behind.
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