A research team at the New Jersey Center for Biomaterials and Osiris Therapeutics, Inc. has demonstrated that cryopreserved human amniotic membrane and umbilical vein tissues have significant antibacterial activity and can inhibit the planktonic growth and the biofilm formation of bacterial pathogens associated with chronic wound sites.
Persistent non-healing wounds present ongoing treatment challenges to healthcare workers. Normal healing can be compromised by poor circulation and nerve damage as occur in the limbs of people with diabetes, by a weakened immune system, and by infection of the site. Drugs and treatment strategies based on synthetic materials are under constant development and if they demonstrate successful healing, they begin to be adopted by clinicians.
NJCBM researchers took a different approach by studying the antibacterial characteristics of amniotic membranes and umbilical vein tissues. Earlier researchers had shown the wound-healing benefits of using fresh placental tissues on chronic wounds. However, to enable wide clinical use, these tissues, donated after childbirth, would have to be preserved in a way that would retain all the functions of the fresh tissue. Osiris has developed a proprietary process for cryopreservation that retains many of the biological functions of the fresh tissue. The team showed that the cryopreserved amniotic membranes secreted antimicrobial proteins that significantly suppressed the growth of several pathogens that contribute to infections in wounds, including methicillin-resistant S. aureus, MRSA. This work was reported in 2017 in Scientific REPORTS | 7: 13722 | DOI:10.1038/s41598-017-13310-6.
Biofilms are communities of bacteria that attach to surfaces and create their own protective polymer matrix. Biofilms are so resistant to antimicrobial treatments that they have to be removed by surgical excision. Developing an advanced wound treatment that can suppress biofilm formation and/or treat a newly-debrided wound would be a substantial contribution. The NJCBM team studied the effects of proteins secreted from both cryopreserved amniotic membranes and cryopreserved umbilical tissue on two bacteria, S. aureus and P. aeruginosa. These are two of the key bacterial species that form biofilms on chronic wounds. Liquid media that contained secreted proteins from either cryopreserved amniotic membranes or cryopreserved umbilical tissue were able to inhibit biofilm formation by both bacterial species on either synthetic surfaces or in porcine dermal tissues. This exciting result supports a role for cryopreserved amniotic membrane and cryopreserved umbilical tissue as beneficial biomaterials for the management of chronic wounds. The full research report was published in 2018 in J. Funct. Biomater. 2018, 9, 3; doi:10.3390/jfb9010003.
Human cryopreserved viable amniotic membrane (hCVAM) had the same structure as fresh amniotic membrane as shown by Hematoxylin&Eosin staining (A). The cell viability in hCVAM is also preserved as shown by Live (green)/dead (red) viability staining (B). hCVAM significantly inhibits the growth of P.aeruginosa (C) and MRSA (D). ***p<0.001