Company: FTII
Filing Date: 2025-02-14
Form Type: S-4
Source: 0001493152-25-006997
Chunk: 352

Company: FutureTech II Acquisition Corp.
Filing Date: 2025-02-14
Form: S-4
Chunk 352
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Flow cytometry
was performed on tissue samples from six study participants with excision time points between 1 and 6 weeks. Immune populations present
inside and around the AAT implants were quantified relative to multiple subject-matched normal adjacent adipose samples also collected
at the time of implant excision. CD45 immune cells (as a percentage of the total live cells) varied by subject but were generally
enriched within the AAT scaffold compared to local fat. Within the CD45 immune compartment, granulocytes (CD45CD11bCD15)
were typically less abundant within AAT implants relative to normal fat, while macrophages and T cells were significantly enriched in
AAT. FoxP3 T cells increased within implants, representing recruitment of regulatory T cells (a subset of CD4
T cells) to the AAT scaffold. Cytokine production in scaffold-associated T cells was lower than in T cells isolated from local adipose
tissue, though this difference was only statistically significant across subjects for IFNG. There was no significant difference in IL4
or IL17A production between T cells isolated from AAT versus matched adipose. Polarization of scaffold-associated versus adipose-associated
macrophages were assessed by CD80 and CD163 expression, markers representing classically activated (M1) and alternately activated (M2)
macrophages respectively. Macrophages were identified globally by surface expression of phenotypic markers (CD45CD15
CD11cMHCIICD11bCD14CD68). In the six subjects tested, macrophages present
in both AAT and control fat were primarily alternately activated M2 macrophages (CD163CD80).

Recruitment within
the AAT implant enhanced the M2 phenotype of scaffold-associated macrophages over fat-associated macrophages in most cases, particularly
at early time points. Increases in CD80 expression were primarily found in the double-positive macrophage population (CD163CD80),
which began to expand at approximately two weeks post-injection and increased thereafter over the six weeks studied. AAT implants in subjects
with later excision time points had larger fractions of double-positive macrophages than those with earlier excisions; similarly, early
excision time points were associated with a larger proportion of unpolarized macrophages. Overall, the AAT microenvironment skewed scaffold-associated
macrophages towards a CD163CD80 double positive phenotype in AAT compared to native adip