Antonella Mannini

For more than a century, the human amniotic membrane (hAM) has been recognized as an optimal tool for skin and corneal wound healing. It has attracted considerable attention from researchers in regenerative medicine due to its structural robustness as a scaffold and its content of epithelial and mesenchymal stromal cells, which exhibit low immunogenicity and immunotoxicity while retaining stem cell potential. Moreover, hAM possesses a range of therapeutic properties relevant to the treatment of various diseased tissues. These effects are mediated by extracellular components, including secreted factors, matrix elements, and extracellular vesicles (EVs). Despite this, a detailed characterization of the extracellular vesicles fraction of hAM, particularly regarding its molecular content and functional properties, remains limited. In this minireview, we summarize the available literature with particular attention to ophthalmology. Recent studies suggest that hAM-derived EVs may provide neuroprotective, anti-inflammatory, and pro-regenerative effects, supporting tissue repair and homeostasis in ocular pathologies. Understanding the molecular cargo of these vesicles, including proteins, miRNAs, and signaling molecules, could help unlock their therapeutic potential and guide the development of standardized cell-free treatments. Taken together, hAM-derived EVs represent a compelling cell-free therapeutic platform for ophthalmology, recapitulating many of the beneficial actions of the native tissue. However, clinical translation requires overcoming critical hurdles. We highlight these unresolved challenges, including manufacturing standardization, potency assessment, and reproducibility, while outlining the key safety and regulatory considerations essential for future ocular therapies.

Background: Human Amniotic Membrane (hAM) is endowed with several biological activities and might be considered an optimal tool in surgical treatment for different ophthalmic pathologies. We pioneered the surgical use of hAM to treat retinal pathologies such as macular holes, tears, and retinal detachments, and to overcome photoreceptor damage in age-related macular degeneration. Although hAM contributed to improved outcomes, the mechanisms of its effects are not yet fully understood. The characterization and explanation of the effects of hAM would allow the adoption of this new natural product in different retinal pathologies, operative contexts, and hAM formulations. At this end, we studied the properties of a hAM extract (hAME) on the ARPE-19 cells. Methods and results: A non-denaturing sonication-based technique was developed to obtain a suitable hAME. Viability, proliferation, apoptosis, oxidative stress, and epithelial-mesenchymal transition (EMT) were studied in hAME-treated ARPE-19 cells. The hAME was able to increase ARPE-19 cell viability even in the presence of oxidative stress (H₂O₂, TBHP). Moreover, hAME prevented the expression of EMT features, such as EMT-related proteins, fibrotic foci formation, and migration induced by different cytokines. Conclusions: Our results demonstrate that the hAME retains most of the properties observed in the whole tissue by others. The hAME, other than providing a manageable research tool, could represent a cost-effective and abundant drug to treat retinal pathologies in the future.

The MDR phenomenon has become a major obstacle in the treatment of cancers, and among the strategies to reverse it, the inhibition of P-gp function and expression is essential to increase for effective anticancer drugs. In the present paper, the co-delivery of berberine chloride and tariquidar loaded nanoliposomes was investigated with the aim of enhancing solubility and improving desired effects for the antineoplastic drug and the P-gp inhibitor. Developed nanoliposomes were loaded with the electron-dense enzyme horseradish peroxidase, and analyzed by TEM to investigate their ability to enter in both K562 and K562/DOXO cell lines. Receptor-mediated endocytosis was evidenced for both cell lines. Nanoliposomes were loaded with tariquidar, berberine chloride, or both, maintaining chemical and physical characteristics—i.e., size, homogeneity, and encapsulation efficiency—and high suitability for parenteral administration. Tariquidar was able to reverse the MDR in the K562/DOXO cell line. Tariquidar- and berberine chloride-loaded nanoliposomes showed a significant increase of berberine chloride accumulation in tumor cells, which could be correlated with resensitization of the resistant cells to the antitumor agent. These results suggest that the co-delivery of the P-gp inhibitor, tariquidar, and the cytotoxicity inducer, berberine chloride, looks like a promising approach to overcome the MDR.