Alan M. Hirahara, MD, FRCSC
Orthopaedic SurgeonSpecialist in Sports Medicine

Are Amniotic Fluid Products "Stem Cell" Therapies? A Study of Amniotic Fluid Preparations for Mesenchymal Stem Cells with Bone Marrow Comparison

Panero AJ, Hirahara AM, Andersen AJ, Rothenberg J, Fierro F
American Journal of Sports Medicine
DOI: 10.1177/0363546519829034
PMID: 30844295

April 1st 2019

Background: In vivo amniotic fluid is known to contain a population of mesenchymal stem cells and growth factors and has been shown to assist in healing when used as an adjunct in procedures across multiple medical specialties. It is unclear as to whether amniotic fluid products contain mesenchymal stem cells and if so, do the cells remain viable after processing.

Hypothesis/Purpose: To determine if mesenchymal stem cells, growth factors, and hyaluronan are present in commercially-available amniotic fluid products.

Study Design: Descriptive Laboratory Study

Methods: Seven commercial amniotic fluid companies were invited to participate in the study, and three companies (PalinGen, FloGraft, & Genesis) agreed to participate and donated AFP’s for analysis. The AFP’s were evaluated for the presence of mesenchymal stem cells, various orthopaedic relevant growth factors (PDGF-ββ, VEGF, IL-8, BMP-2, TGF-β1), and hyaluronan by ELISA and CFU-F culture. These products were compared to unprocessed amniotic fluid and two separate samples of mesenchymal stem cells derived from human bone marrow aspirates. All groups used the same culture medium and expansion techniques. Identical testing and analysis procedures were performed for all samples.

Results: Mesenchymal stem cells were unable to be identified in the commercial amniotic fluid products nor the unprocessed amniotic fluid. Mesenchymal stem cells were able to be cultured from the bone marrow aspirates. Nucleated cells were found in two products (PalinGen & FloGraft), but most of these cells were dead. The few living cells did not exhibit established mesenchymal stem cell characteristics. Growth factors and hyaluronan were present in all groups at varying levels.

Conclusion: The amniotic fluid products studied should not currently be considered “stem cell” therapies and caution should be exercised when evaluating commercial claims that products contain stem cells. Given their growth factor content, however, amniotic fluid products may still represent a promising tool for orthopaedics.

Clinical relevance: Amniotic fluid has been proposed as an allogenic means for introducing mesenchymal stem cells. This study was unable to confirm that commercial amniotic fluid products contain mesenchymal stem cells.

Key Terms: Bone marrow aspirate concentrate; Growth factors/Healing enhancement; Amniotic Fluid; Stem Cell Therapy; Mesenchymal Stem Cells