Safety and efficacy of acellular human amniotic fluid and membrane in the treatment of non-healing wounds in a patient with chronic venous insufficiency

Assessing the Safety, Tolerability and Efficacy of Cell-Free Amniotic Fluid in the Treatment of Non-Healing Venous Ulcers: Initial Experience From a Prospective, Multicenter, Phase II Study

Non-healing venous leg ulcers represent a significant healthcare problem that accounts for about $32 billion of spending in the US alone. Consequently, novel treatment strategies represent a major unmet need. The current study (part one of Phase II study [NCT04647240]) assesses the safety, tolerability and efficacy of the use of cell-free human amniotic fluid in treating venous leg ulcers that did not heal following the correction of venous reflux. Patients received cell-free amniotic fluid injections in and around the wound either weekly or biweekly over 12 weeks. Primary outcomes included safety, tolerability and efficacy assessed by complete wound closure, wound area reduction and pain reduction. Eleven patients met enrollment eligibility, and nine completed the study. Five patients achieved complete wound closure by week 12. The average percent reduction in wound area was 83.7%, and pain scores were significantly lower by the study endpoint. No difference was observed in wound healing rates between weekly or biweekly treatment, but bi-weekly treatment was associated with nominally faster recovery. Patients tolerated the treatment, and no side effects were reported. These results indicate that cell-free amniotic fluid injection is a feasible, safe and effective treatment for non-healing venous leg ulcers.

Amniotic Fluid Reduces Liver Fibrosis By Attenuating Hepatic Stellate Cell Activation

Regardless of the source of injury or metabolic dysfunction, fibrosis is a frequent driver of liver pathology. Excessive liver fibrosis is caused by persistent activation of hepatic stellate cells (HSCs), which is defined by myofibroblast activation (MFA) and the epithelial-mesenchymal transition (EMT). Strategies to prevent or reverse this HSC phenotype will be critical for successful treatment of liver fibrosis. We have previously shown that full-term, cell-free human amniotic fluid (cfAF) inhibits MFA and EMT in fibroblasts in vitro. We hypothesize that cfAF treatment can attenuate HSC activation and limit liver fibrosis. We tested if cfAF could prevent liver fibrosis or HSC activation in murine models of liver damage, three-dimensional hepatic spheroids, and HSC cultures. Administering cfAF prevented weight loss and the extent of fibrosis in mice with chronic liver damage without stimulating deleterious immune responses. Gene expression profiling and immunostaining indicated that cfAF administration in carbon tetrachloride-treated mice reduced EMT- and MFA-related biomarker abundance and modulated transcript levels associated with liver metabolism, immune regulatory pathways, and cell signaling. cfAF treatment lowered MFA biomarker levels in a dose-dependent manner in hepatic spheroids exposed to ethanol. Treating HSCs with cfAF in vitro strongly repressed EMT. Multi-omics analyses revealed that it also attenuates TGFβ-induced MFA and inflammation-associated processes. Thus, cfAF treatment prevents liver fibrosis by safeguarding against persistent HSC activation. These findings suggest that cfAF may be a safe and effective therapy for reducing liver fibrosis and preventing the development of cirrhosis and/or hepatocellular carcinoma.

Amniotic Membrane Transplantation: Clinical Applications in Enhancing Wound Healing and Tissue Regeneration

Chronic wounds and non-healing tissue defects pose significant clinical challenges, necessitating innovative therapeutic approaches. A comprehensive literature review of amniotic membrane transplantation for wound healing and tissue repair evaluates the efficacy and safety of amniotic membrane transplantation in enhancing wound healing and tissue repair. Amniotic membranes promote wound closure and reduce inflammation and scarring via abundant growth factors, cytokines, and extracellular matrix components, which foster conducive environments for tissue regeneration. Amniotic membrane transplantation is effective in various medical disciplines, including ophthalmology, dermatology, and orthopedics. Low immunogenicity and anti-microbial properties ensure their safe application. Amniotic membrane transplantation offers a promising therapeutic approach for wound healing and tissue repair, and further research is warranted to explore its regenerative potential fully.

Use of amniotic membrane in hard-to-heal wounds: a multicentre retrospective study

OBJECTIVE

Hard-to-heal (chronic) wounds negatively impact patients and are a source of significant strain on the healthcare system and economy. These wounds are often resistant to standard of care (SoC) wound healing approaches due to a diversity of underlying pathologies. Cellular, acellular, and matrix-like products, such as amniotic membranes (AM), are a potential solution to these challenges. A growing body of evidence suggests that AM may be useful for treatment-resistant wounds; however, limited information is available regarding the efficacy of dehydrated amniotic membrane (DHAM) on multi-aetiology, hard-to-heal wounds. Therefore, we analysed the efficacy of DHAM treatment in reducing the size of hard-to-heal diabetic and venous leg ulcers (VLUs) that had failed to improve after SoC-based treatments.

METHOD

In this multicentre retrospective study, we analysed wound size during clinic visits for patients being treated for either diabetic or VLUs. During each visit, the treatment consisted of debridement followed by application of DHAM. Each wound was measured after debridement and prior to DHAM application, and wound volumes over time or number of DHAM applications were compared.

RESULTS

A total of 18 wounds in 11 patients were analysed as part of this study. Wounds showed a significant reduction in volume after a single DHAM application, and a 50% reduction in wound size was observed after approximately two DHAM applications. These findings are consistent with reports investigating DHAM treatment of diabetic ulcers that were not necessarily resistant to treatment.

CONCLUSION

To our knowledge, this study is the first to directly compare the efficacy of standalone DHAM application to hard-to-heal diabetic and venous leg ulcers, and our findings indicate that DHAM is an effective intervention for resolving these types of wounds. This suggests that implementing this approach could lead to fewer clinic visits, cost savings and improved patient quality of life.

DECLARATION OF INTEREST

This research was supported in part by Merakris Therapeutics, US, and facilitated access to deidentified patient datasets, which may represent a perceived conflict of interest; however, the primary data analysis was performed by FSB who is unaffiliated with Merakris Therapeutics. TCB is a founder, employee of and shareholder in Merakris Therapeutics; WSF is a co-founder of, consultant for, and shareholder in Merakris Therapeutics, and was also supported by the National Institutes of Health National Center for Advancing Translational Sciences Clinical and Translational Science Awards Grant KL2 Scholars Program (KL2TR001441). The research was also supported through endowments to WSF from the University of Texas Medical Branch Mimmie and Hallie Smith Endowed Chair of Transplant Research and the John L Hern University Chair in Transplant Surgery.

Cell-Free Amniotic Fluid and Regenerative Medicine: Current Applications and Future Opportunities

Amniotic fluid (AF) provides critical biological and physical support for the developing fetus. While AF is an excellent source of progenitor cells with regenerative properties, recent investigations indicate that cell-free AF (cfAF), which consists of its soluble components and extracellular vesicles, can also stimulate regenerative and reparative activities. This review summarizes published fundamental, translational, and clinical investigations into the biological activity and potential use of cfAF as a therapeutic agent. Recurring themes emerge from these studies, which indicate that cfAF can confer immunomodulatory, anti-inflammatory, and pro-growth characteristics to the target cells/tissue with which they come into contact. Another common observation is that cfAF seems to promote a return of cells/tissue to a homeostatic resting state when applied to a model of cell stress or disease. The precise mechanisms through which these effects are mediated have not been entirely defined, but it is clear that cfAF can safely and effectively treat cutaneous wounds and perhaps orthopedic degenerative conditions. Additional applications are currently being investigated, but require further study to dissect the fundamental mechanisms through which its regenerative effects are mediated. By doing so, rational design can be used to fully unlock its potential in the biotechnology lab and in the clinic.

Comparative Analysis of Co-Cultured Amniotic Cell-Conditioned Media with Cell-Free Amniotic Fluid Reveals Differential Effects on Epithelial–Mesenchymal Transition and Myofibroblast Activation

Myofibroblast activation is a cellular response elicited by a variety of physiological or pathological insults whereby cells initiate a coordinated response intended to eradicate the insult and then revert back to a basal state. However, an underlying theme in various disease states is persistent myofibroblast activation that fails to resolve. Based on multiple observations, we hypothesized that the secreted factors harvested from co-culturing amniotic stem cells might mimic the anti-inflammatory state that cell-free amniotic fluid (AF) elicits. We optimized an amnion epithelial and amniotic fluid cell co-culture system, and tested this hypothesis in the context of myofibroblast activation. However, we discovered that co-cultured amniotic cell conditioned media (coACCM) and AF have opposing effects on myofibroblast activation: coACCM activates the epithelial–mesenchymal transition (EMT) and stimulates gene expression patterns associated with myofibroblast activation, while AF does the opposite. Intriguingly, extracellular vesicles (EVs) purified from AF are necessary and sufficient to activate EMT and inflammatory gene expression patterns, while the EV-depleted AF potently represses these responses. In summary, these data indicate that coACCM stimulates myofibroblast activation, while AF represses it. We interpret these findings to suggest that coACCM, AF, and fractionated AF represent unique biologics that elicit different cellular responses that are correlated with a wide variety of pathological states, and therefore could have broad utility in the clinic and the lab.