Amniotic Fluid Products Probably Don’t Contain Stem Cells, but May Still Modulate Healing

Mar 8

Amniotic Fluid Products Probably Don’t Contain Stem Cells, but May Still Modulate Healing

In vivo amniotic fluid is known to contain growth factors and mesenchymal stem cells (MSCs), which prior research has suggested may aid in tissue healing. Several companies have injectable amniotic fluid products  (AFPs) on the market based on this  prior research, but it’s unclear exactly what the composition of these AFPs is and whether they contain viable MSCs that could participate in healing. To clarify these lingering questions, upcoming TOBI conference speaker Dr. Panero and several of his colleagues at the University of California in Davis published a paper in the American Journal of Sports Medicine evaluating several AFPs to determine their cellular composition.

 

Significant controversy exists around whether AFPs contain viable MSCs. Many of the studies reporting viable cells tested samples either during the second trimester of pregnancy or immediately after birth. Significant uncertainty remains about whether these cells survive cryopreservation and remain clinically viable when subsequently used for therapeutic purposes.

 

To test this, the authors solicited product samples from seven commercial companies and eventually received samples from three including PalinGen (BioPro), FloGraft (Applied Biologics), and Genesis (Genesis Biologics). Cell viability was tested by visualizing cells microscopically using tryptan blue. Once dyed, the samples were examined with cells only deemed viable if no dye crossed the cell membrane. Samples were also incubated for several days and examined for MSC cell culture expansion to verify viability. The samples were then examined for growth factors including platelet-derived growth factor with 2 b subunits (PDGF-bb), bone morphogenetic protein 2 (BMP-2), interleukin 8 (IL-8), vascular endothelial growth factor (VEGF), and transforming growth factor b1 (TGF-b1). The authors also tested for hyaluronan.

 

Importantly, the commercial samples were compared to unprocessed samples of amniotic fluid obtained through the university. This amniotic fluid was cryopreserved without cryopreservation agents to see if any cells would survive. Bone marrow aspirates were also included as a control to ensure that cell culture expansion would occur as expected.

 

When the authors examined the AFPs, they found no MSCs either immediately after thawing or after culture expansion. Of note, this was expected for the Genesis product since it’s acellular. Viable MSCs were also absent in the unprocessed amniotic fluid indicating likely cell death from the cryopreservation process. Some of the commercial samples contained nucleated cells, but most were dead and none exhibited MSC properties. The protein analysis revealed highly variable concentrations of the proteins tested, but all contained three to four of those studied.

 

The authors note that the reason behind the absence of MSCs in the commercial products is still unclear. While cryopreservation can clearly damage cells, it may also be the case that manufacturing and processing of these cellular products may be harmful to MSCs. The authors also comment that even if some of the viable nucleated cells were MSCs, they were present in such low numbers as to be clinically meaningless from a therapeutic perspective. 

 

The presence of the proteins found in the samples, however, does point to a possible immunomodulatory effect of AFPs that may potentiate the healing process. These proteins are present on a much more reliable basis and are potentially contributing to or causing many of the healing properties observed in prior studies.

 

If you’re looking to learn more about which regenerative therapies might work best for your patients, consider attending TOBI X 2019, June 6-8, 2019 in Chicago. We are honored to Dr. Panero present and participate in the PMR and orthopedic surgeon panel “PRP, BMC, lipoaspirate, amniotic cells: Which do I choose?” The panel will include Dr. Panero as well as Drs. Borg-Stein, Buford, Dragoo, Farr and Shiple.

Congratulations TOBI Faculty, Dr. Alberto Panero and Dr. Alan Hirahara, on this insightful new contribution to the literature, published  in American Journal of Sports Medicine.

Are Amniotic Fluid Products Stem Cell Therapies? A Study of Amniotic Fluid Preparations for Mesenchymal Stem Cells With Bone Marrow Comparison – Alberto J. Panero, Alan M. Hirahara, Wyatt J. Andersen, Joshua Rothenberg, Fernando Fierro, 2019

See the study here: https://journals.sagepub.com/doi/pdf/10.1177/0363546519829034

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