Preparation of human amniotic membrane for transplantation in different application areas

Potential novel role of the human amniotic membrane as a sustainable hemostat

OBJECTIVES

Acute hemorrhage can cause significant morbidity and mortality arising from trauma, bleeding disorders, surgical procedures, or obstetric complications. Surgical hemostasis methods may fail to stop acute bleeding due to the complex bleeding dynamics of each bleeding type. Therefore, developing safe and effective topical hemostatic agents remains crucial. The human amniotic membrane (hAM) has established clinical evidence of effectiveness in promoting wound healing and tissue regeneration. Despite its unique biological and immunologic properties and its structural composition of established hemostatic elements, the hemostatic role of hAM has not been yet explored. The present study aimed to investigate this potential role and to describe the development protocol and characterization of hAM-derived topical hemostat.

METHODS

Surface electron microscope (SEM) imaging and Fourier transform infrared (FTIR) spectroscopy were used for characterization, and mouse models with induced peritoneal and tail wound bleeding were employed to evaluate the hemostatic effectiveness using physiological studies, in comparison to a chitosan-based combat-scale hemostat.

RESULTS

The hAM hemostat showed a distinctive composition by SEM and FTIR. Applying equal masses of the hAM hemostat, the commercial hemostat, or a combination reduced peritoneal wound bleeding time to averages of 108.4, 86.2, and 76.8 s, respectively, compared to the control group (300 s). Tail wound bleeding times were similarly reduced with no significant difference between the hAM and the commercial hemostat (P values = 0.29, 0.34 in peritoneal and tail wounds, respectively). Neither hemostat affected coagulation time.

CONCLUSION

This study describes a simple cost-effective preparation protocol for a hAM-based hemostatic agent. The long-recognized safety, sustainability, and immunotolerance advantages of hAM can establish superiority over commercial hemostats with reported safety concerns. Robust research validation in larger-scale bleeding models is required for wider applications and severe bleeding types.

Dehydrated human amnion/chorion membrane allograft with spongy layer to significantly improve the outcome of chronic non-healing wounds

We investigated the healing effect of a new dehydrated amnion/chorion membrane with a spongy layer over a 30-month period in 32 patients with 53 chronic non-healing wounds of different aetiologies. Wounds with <40% surface reduction after 4 weeks of best wound treatment underwent weekly allograft application by a certified wound specialist based on national guidelines and a standardised protocol until complete healing or definite treatment interruption. The main outcome measure was the percentage of wound surface reduction from baseline calculated using digital planimetry follow-up photographs. Overall, 38 (71.7%) wounds presented a favourable outcome (70%-100% area reduction), with 35 (66%) completely healing over a median time of 77 days (range 29-350 days). Favourable outcomes were observed in 75% of traumatic wounds, surgical wounds, venous leg ulcers and pressure injuries, as well as in 50% of ischaemic wounds. Wounds being present <12 months were significantly more likely to have a favourable outcome than more long-standing wounds (χ2  = 7.799; p = 0.005; OR = 3.378; 95% CI, 1.410-8.092). Thus, treatment with dehydrated amnion/chorion membrane with a spongy layer improves the outcome of non-healing wounds of different aetiologies and, therefore, has to be considered early in the management of refractory wounds.