Transforming growth factor–β1 (TGF-β1) plays a central role in normal and aberrant wound healing, but the precise mechanism in the local environment remains elusive. Here, using a mouse model of aberrant wound healing resulting in heterotopic ossification (HO) after traumatic injury, we find autocrine TGF-β1 signaling in macrophages, and not mesenchymal stem/progenitor cells, is critical in HO formation. In-depth single-cell transcriptomic and epigenomic analyses in combination with immunostaining of cells from the injury site demonstrated increased TGF-β1 signaling in early infiltrating macrophages, with open chromatin regions in TGF-β1–stimulated genes at binding sites specific for transcription factors of activated TGF-β1 (SMAD2/3). Genetic deletion of TGF-β1 receptor type 1 ( Tgfbr1 ; Alk5 ), in macrophages, resulted in increased HO, with a trend toward decreased tendinous HO. To bypass the effect seen by altering the receptor, we administered a systemic treatment with TGF-β1/3 ligand trap TGF-βRII-Fc, which resulted in decreased HO formation and a delay in macrophage infiltration to the injury site. Overall, our data support the role of the TGF-β1/ALK5 signaling pathway in HO.

Background/Objectives: Arterial coupling in microsurgery remains technically challenging despite widespread venous coupler adoption. We developed a novel everter device to facilitate arterial anastomosis using mechanical couplers and evaluated its feasibility and potential efficiency in abdominal-based breast reconstruction. Methods: Five pigs underwent paired superior epigastric artery flap reconstruction with everter-assisted and hand-sewn arterial anastomoses, analyzed using a paired t-test. A retrospective clinical series included 12 patients, 22 reconstructed breasts, 14 coupling attempts, and 8 primary hand-sewn recipient arterial anastomoses. The primary clinical outcome was successful coupling without revision or conversion. Clinical timing comparisons were descriptive. Results: All five porcine arterial couplings were successful. Mean arterial time was 8.47 ± 2.83 min versus 20.26 ± 3.32 min for hand-sewn controls, a paired reduction of 11.79 min (95% CI, 5.86 to 17.72; p = 0.005). Clinical coupling succeeded in 9 of 14 attempts (64.3%). Five attempts required conversion (35.7%), including three thrombotic and two technical failures. All were converted intraoperatively, with no flap loss. Mean arterial times were 9.2 ± 4.2 min for successful coupling (n = 8) and 20.2 ± 8.0 min for primary hand-sewn anastomosis (n = 6), an approximately 55% difference. Conclusions: Everter-assisted arterial coupling demonstrated clinical feasibility and shorter mean arterial times when successfully completed. These findings support further refinement and evaluation of the technique to establish safety and overall procedural efficiency.