Preliminary Cellular and Contamination-Related Observations From Adinizer-Processed Microfragmented Adipose Tissue: A...

Background Microfragmented adipose tissue (MFAT) is a mechanically processed adipose-tissue preparation that retains extracellular matrix and heterogeneous stromal and immune cell populations. Because intact MFAT is not a single-cell suspension, cellular enumeration requires laboratory dissociation. This retrospective technical note describes preliminary cellular observations and limited contamination screening results in Adinizer-processed MFAT from three donors. Methods De-identified laboratory records from three female donors were retrospectively reviewed with institutional review board approval and written informed consent. Residual lipoaspirate was mechanically processed using serial Adinizer cutting units (2400, 1200, 600, and 400 μm; five passes at each size), centrifuged at 1,200 × g for 5 minutes, cleared of the upper oil-containing layer, and passed through a final 200-μm cutting unit. A 3-mL aliquot of refined MFAT was enzymatically dissociated. Cell concentration and viability were measured in duplicate as technical replicates and averaged. Cells were stained for CD34, CD45, CD90, and CD146. Mycoplasma and endotoxin findings were reviewed as limited contamination screening results. Results Donor ages ranged from 43 to 70 years and BMI from 34.5 to 39.9 kg/m². Mean recovered cell concentrations ranged from 1.41 × 10⁵ to 8.41 × 10⁵ cells/mL, corresponding to 2.82 × 10⁵ to 1.68 × 10⁶ total recovered cells from each 3-mL aliquot. Mean viability ranged from 65.8% to 78.6%, with calculated viable recovered cell counts of 2.11 × 10⁵ to 1.32 × 10⁶. Laboratory-reported ASC-like fractions ranged from 15.4% to 24.4%, and leukocyte fractions from 22.6% to 32.0%. Mycoplasma testing was negative in all samples, and all endotoxin results met the laboratory acceptance criterion of <1 EU/mL. Conclusions Viable cells, including a laboratory-defined ASC-like fraction, were recovered after enzymatic liberation of Adinizer-processed MFAT. Recovered cell yield varied substantially among donors, with no consistent monotonic pattern across the obese BMI range represented. The ASC-like fraction suggests preservation of a stromal/progenitor-compatible cellular component after mechanical processing; however, the limited marker panel and absence of functional assays preclude conclusions regarding definitive mesenchymal stromal/stem-cell identity or functional stemness. Mycoplasma and endotoxin findings should be interpreted only as limited contamination screening results, not as evidence of sterility or product safety. Larger prospective studies with complete flow-cytometric documentation, broader marker panels, and functional assays are required.