Drug reservoir function of voriconazole impregnated human amniotic membrane: An in vitro study

Amniotic miracle: Investigating the unique development and applications of amniotic membrane in wound healing

BACKGROUND

The perfect repair of damaged skin has always been a constant goal for scientists; however, the repair and reconstruction of skin is still a major problem and challenge in injury and burns medicine. Human amniotic membrane (hAM), with its good mechanical properties and anti-inflammatory, antioxidant and antimicrobial benefits, containing growth factors that promote wound healing, has evolved over the last few decades from simple skin sheets to high-tech dressings, such as being made into nanocomposites, hydrogels, powders, and electrostatically spun scaffolds. This paper aims to explore the historical development, applications, trends, and research hotspots of hAM in wound healing.

METHODS

We examined 2660 publications indexed in the Web of Science Core Collection (WoSCC) from January 1, 1975 to July 12, 2023. Utilizing bibliometric methods, we employed VOSviewer, CiteSpace, and R-bibliometrix to characterize general information, identify development trends, and highlight research hotspots. Subsequently, we identified a collection of high-quality English articles focusing on the roles of human amniotic epithelial stem cells (hAESCs), human amniotic mesenchymal stem cells (hAMSCs), and amniotic membrane (AM) scaffolds in regenerative medicine and tissue engineering.

RESULTS

Bibliometric analysis identified Udice-French Research Universities as the most productive affiliation and Tseng S.C.G. as the most prolific author. Keyword analysis, historical direct quotations network, and thematic analysis helped us review the historical and major themes in this field. Our examination included the knowledge structure, global status, trends, and research hotspots regarding the application of hAM in wound healing. Our findings indicate that contemporary research emphasizes the preparation and application of products derived from hAM. Notably, both hAM and the cells isolated from it - hADSCs and hAESCs are prominent and promising areas of research in regenerative medicine and tissue engineering.

CONCLUSION

This research delivers a comprehensive understanding of the knowledge frameworks, global dynamics, emerging patterns, and primary research foci in the realm of hAM applications for wound healing. The field is rapidly evolving, and our findings offer valuable insights for researchers. Future research outcomes are anticipated to be applied in clinical practice, enhancing methods for disease prevention, diagnosis, and treatment.

Safety Considerations for Lyophilized Human Amniotic Membrane Impregnated with Colistin and Silver Nanoparticles

Lyophilized human amniotic membrane (HAM) and silver nanoparticles (AgNPs) have multispectral applications as a biological dressing. The present study focuses on the safety aspects of HAM coated with colistin and AgNPs (HACoN) dressing in relation to its structural and hematological changes. Four dressing groups were designed for the study, HAM, HAM coated with colistin (HACo), HAM coated with AgNPs (HAN), and HAM coated with colistin (HACo) and HACoN. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were utilized for constitutional analysis. Biological safety was checked by applying HAM of all groups on open excisional burn wounds on Sprague-Dawley rats for 21 days. The skin, kidneys, liver, and spleen were removed, and histological analysis was performed for detailed structural analysis. Oxidative stress was assessed using homogenate from newly generated skin. No structural or biochemical change was observed in any of the study groups as observed by SEM and FTIR. After 21 days of grafting, wounds were healed properly with normal skin, and no anomaly was observed in related to kidneys, spleen, and liver. Some of antioxidant enzymes were increased, while malondialdehyde which is a reactive oxygen species was reduced in the skin tissue homogenate of HACoN group. Impregnation of colistin and AgNPs in combination on HAM has no effects on hematological and structural constitution of HAM. It leaves no obvious change in vital organs of rats and improves oxidative stress and inflammation. Hence, it can be claimed that HACoN is a biologically safe antibacterial dressing.

Voriconazole-impregnated multilayered AMT and intracorneal plus intracameral injection in recalcitrant fungal corneal ulcer

We describe the management of a referred man in his 50s with corneal ulcer in the left eye. Slit-lamp biomicroscopy revealed an infiltrate (4.5×3.5 mm), involving full corneal thickness, corneal melt less than one-third corneal thickness and hypopyon (3.0 mm). Branched septate hypha on direct microscopy and Aspergillus flavus in Sabaraud's dextrose agar confirmed the clinical diagnosis of fungal corneal ulcer. We used natamycin 5% suspension 1 hourly, voriconazole 1% 1 hourly, gatifloxacin 0.5% three times and atropine 1% three times per day, for 2 weeks. However, there was no improvement and the corneal melt increased. We used intracameral plus intracorneal voriconazole injection with voriconazole-impregnated amniotic membrane transplant. We observed a significant decrease in conjunctival congestion, size/depth of infiltrate and hypopyon at the first week of antifungal therapy. Subsequently, at 6 weeks, corneal infiltrate had decreased and superficial corneal vascularisation appeared. Later, at 12 weeks, the patient developed corneal opacity.

Efficacy of rhNGF-loaded amniotic membrane transplantation for rabbit corneal epithelial and nerve regeneration

AIM

To evaluate the efficacy of recombinant human nerve growth factor-loaded amniotic membrane (rhNGF-AM) on corneal epithelial and nerve regeneration in rabbit model.

METHODS

Freshly prepared human amniotic membrane (AM) were immersed into PBS buffer containing 100 or 500 µg/mL rhNGF for 15, 30, and 60min at 4°C. The in vitro release kinetics of rhNGF was measured with ELISA. For in vivo evaluation, the AM were immersed with 500 µg/mL rhNGF for 30min. Fifty-seven rabbits were selected to establish corneal epithelial defect model. In addition to the 19 rabbits in control group, 38 rabbits received AM transplantation with or without rhNGF after the removal of central epithelium. Corneal epithelial defect area, sub-epithelial nerve fiber density, corneal sensitivity, rhNGF contents in resident AM and corneas were measured after the surgery.

RESULTS

rhNGF was sustained release from the AM within 14d in vitro, with the positive correlation with initial immersion concentration. The immersion of AM in 500 µg/mL rhNGF for 30min achieved the most stable release within 14d. After transplantation in rabbit cornea, a high concentration of rhNGF in resident rhNGF-AM and cornea was maintained within 8d. Corneal epithelial healing, nerve fiber regeneration and the recovery of corneal sensitivity were significantly accelerated after the rhNGF-AM transplantation when compared to simple AM transplantation (all P<0.05).

CONCLUSION

Simple immersion of AM achieves the sustained release of rhNGF, and promotes corneal epithelial wound healing and nerve regeneration, as well as the recovery of corneal sensitivity in rabbit.