FGF2 and EGF for the Regeneration of Tympanic Membrane: A Systematic Review

Efficacy of Concentrated Growth Factors in Treating Tympanic Membrane Perforation in Guinea Pigs

Background: Less invasive and cost-effective alternatives are needed to manage tympanic membrane perforation (TMP). Therefore, the effectiveness of concentrated growth factors (CGF) in promoting tympanic membrane regeneration in guinea pig models of eardrum perforation was invetigeted. Methods: Large TMPs were created in 34 guinea pig ears using a CO2 laser and divided into 3 groups: CGF-gelatin sponge (with-CGF group), saline-gelatin sponge (without-CGF group), and untreated group. In the with-CGF group, CGF and gelatin sponges were implanted into the perforations, while the without-CGF group received gelatin sponges impregnated with saline. Eardrums were observed under a light microscope on days 14 and 28, and tympanic membranes were examined histologically with hematoxylin and eosin staining. Results: On day 14, 8 of 14 (57.1%) ears in the with-CGF group achieved perforation closure, while no closures were observed in the withoutCGF or untreated groups. The closure rate was significantly higher in the with-CGF group compared to both without-CGF and untreated groups (P < .001). By day 28, 12 of 14 (85.7%) ears in the with-CGF group and 8 of 14 (57.1%) ears in the without-CGF group had closure. No closures were noted in the untreatedgroup. Although the closure rates between the with-CGF and without-CGF groups were similar (P=.07), the withCGF group showed a significantly higher rate than the untreated group (P < .001). Histological analysis revealed that the regenerated tympanic membrane was thicker in the with-CGF group compared to the without-CGF group. Conclusion: Concentrated growth factor effectively promotes tympanic membrane regeneration and provides a promising, minimally invasive treatment option for TMP.

Bioactive peptides and proteins for tissue repair: microenvironment modulation, rational delivery, and clinical potential

Bioactive peptides and proteins (BAPPs) are promising therapeutic agents for tissue repair with considerable advantages, including multifunctionality, specificity, biocompatibility, and biodegradability. However, the high complexity of tissue microenvironments and their inherent deficiencies such as short half-live and susceptibility to enzymatic degradation, adversely affect their therapeutic efficacy and clinical applications. Investigating the fundamental mechanisms by which BAPPs modulate the microenvironment and developing rational delivery strategies are essential for optimizing their administration in distinct tissue repairs and facilitating clinical translation. This review initially focuses on the mechanisms through which BAPPs influence the microenvironment for tissue repair via reactive oxygen species, blood and lymphatic vessels, immune cells, and repair cells. Then, a variety of delivery platforms, including scaffolds and hydrogels, electrospun fibers, surface coatings, assisted particles, nanotubes, two-dimensional nanomaterials, and nanoparticles engineered cells, are summarized to incorporate BAPPs for effective tissue repair, modification strategies aimed at enhancing loading efficiencies and release kinetics are also reviewed. Additionally, the delivery of BAPPs can be precisely regulated by endogenous stimuli (glucose, reactive oxygen species, enzymes, pH) or exogenous stimuli (ultrasound, heat, light, magnetic field, and electric field) to achieve on-demand release tailored for specific tissue repair needs. Furthermore, this review focuses on the clinical potential of BAPPs in facilitating tissue repair across various types, including bone, cartilage, intervertebral discs, muscle, tendons, periodontal tissues, skin, myocardium, nervous system (encompassing brain, spinal cord, and peripheral nerve), endometrium, as well as ear and ocular tissue. Finally, current challenges and prospects are discussed.

Controlled Release of Mesenchymal Stem Cell-Conditioned Media from a Microsphere/Gel-Based Drug Delivery System for Wound Healing of Tympanic Membrane Perforations

Chronic tympanic membrane (TM) perforation increases patient susceptibility to infection, hearing loss, and other side effects. Current clinical treatment, surgical grafting, can result in detrimental side effects including nerve damage, dizziness, or hearing loss. Therefore, it is essential to develop novel therapeutic procedures that can induce or accelerate healing in minimally or noninvasive approaches. Cell-free therapies have safety advantages over stem cells and are logistically favorable for clinical use. The regenerative potential by mesenchymal stem cell-conditioned media (CM) has been promising. In this study, poly(lactic-co-glycolic acid) (PLGA) microspheres with CM encapsulated have been developed as a cell-free alternative regenerative treatment for TM perforation. The results suggest that the PLGA microspheres were capable of encapsulating and releasing CM for up to 21 days. The in vitro scratch wound proliferation assays showed increased wound healing ability of CM-loaded microspheres. In vivo guinea pig models treated with CM drops and CM-loaded microspheres using a thermoresponsive gel carrier demonstrated potential for wound healing in TM perforation. These studies provide a basis for further examination of the delivery of stem cell CM and investigation of time-dependent wound healing, long-term ototoxicity, and hearing restoration.

Prevention and Repair of Ultraviolet B-Induced Skin Damage in Hairless Mice via Transdermal Delivery of Growth Factors Immobilized in a Gel-in-Oil Nanoemulsion

Ultraviolet (UV) radiation from the sun or artificial sources is one of the primary causes of skin damage, including sunburns, tanning, erythema, and skin cancer. Among the three different types of UV rays, UVB rays have a medium wavelength that can penetrate the epidermal layer of the skin, resulting in sunburn, suntan, blistering, and melanoma in case of chronic exposure. This study aimed to evaluate the preventive and therapeutic effects of a gel-in-oil nanogel dispersion (G/O-NGD) as a transdermal delivery biomolecular carrier for skin damage caused by UVB light. The efficacy of this carrier against UVB-induced skin damage was investigated in vivo by delivering different growth factors (GFs) encapsulated in a G/O-NGD. Artificial UVB light was used to induce skin damage in nude mice, followed by the transdermal application of five GF [vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), transforming growth factor (TGF)-1, and insulin-like growth factor (IGF)-α]-immobilized G/O-NGD. Among these GFs, VEGF and bFGF promoted angiogenesis, while EGF, TGF-1, and IGF-α promoted the repair and regeneration of damaged cells. The results showed that G/O-NGD was superior to heparin-immobilized G/O-NGD in reducing UVB-induced skin damage, such as erythema, epidermal water reduction, inflammation, and dermis thickening. In addition, G/O-NGD could prevent and treat abnormal follicle proliferation caused by UVB rays and exhibited potential to repair lipid glands. Overall, our results demonstrate the potential of G/O-NGDs for the treatment of UVB-induced skin damage.

Clinical Effect of Emergency Dermabrasion Combined with Biological Dressing A on Wound Microcirculation and Preventing Sepsis in Deep Degree-II Burns

Objective

The aim of this study is to explore the clinical effect of emergency dermabrasion combined with biological dressing A on wound microcirculation and preventing sepsis in deep degree-II burns.

Methods

A total of 90 patients with deep degree-II burns admitted to the hospital were retrospectively enrolled between January 2020 and January 2022. According to different treatment methods, they were divided into the control group (42 cases, biological dressing A) and the observation group (48 cases, emergency dermabrasion combined with biological dressing A). The clinical curative effect in both groups was observed. The wound repair rate and wound healing quality, and changes in levels of wound microcirculation-related indexes (serum epidermal growth factor (EGF), wound blood flow, and partial pressure of transcutaneous oxygen) and inflammatory cytokines (C-reactive protein (CPR), interleukin-6 (IL-6), erythrocyte sedimentation rate (ESR), and procalcitonin (PCT)) before treatment, at 3d and 7d after treatment were compared between the two groups. The incidence of wound infection and sepsis in both groups was recorded.

Results

The wound healing time in the observation group was significantly shorter than that in the control group, and wound healing quality in the observation group was better than that in the control group (P < 0.05). At 3 d and 7d after treatment, the levels of serum EGF, wound blood flow and partial pressure of transcutaneous oxygen in both groups were all increased (P < 0.05), which were higher in the observation group than those in the control group (P < 0.05). The levels of CRP, IL-6, ESR, and PCT in both groups were all decreased (P < 0.05), which were lower in the observation group than those in the control group (P < 0.05). There was no significant difference in incidence of sepsis between observation group and control group (4.17% (2/48) vs. 7.14% (3/42)) (Fisher = 0.539).

Conclusion

Emergency dermabrasion combined with biological dressing A can effectively improve wound microcirculation in patients with deep degree-II burns, promote wound healing, shorten wound healing time, improve wound healing quality, effectively control inflammatory response, and prevent sepsis.