Background Skeletal stem cells (SSCs) have attracted extensive attention for their crucial role in bone accrual and therapeutical values. The substantial unmet cellular need of regenerative medicine and tissue engineering calls for identification of a novel source for human SSC isolation, or even skeletal stem cell-like cells (SSCLCs). Methods hSSCLCs were isolated through enzyme-digestion and fluorescent-activated cell sorting (FACS) from human tissues including placenta, cord blood, Wharton’s Jelly and various adipose depots. Proportion of hSSCLCs in all those tissues were compared through flow cytometry. For adipose tissue, immunofluorescent staining was also employed to substantiate our flow results. In vitro CFU-F assay, chondrogenic and osteogenic assays were performed to assess self-renewal and multipotency for differentiation of hSSCLCs. Transcriptomic profiling of adipose-derived hSSCLCs was achieved through scRNA-seq. Results Here, we illustrated that adipose tissues contain a satisfying abundancy of hSSCLCs, especially infrapatellar fat pad (IPFP), but not fetal tissues. Moreover, we discovered IPFP-derived hSSCLCs display intact self-renewal and a marked elevation in chondrogenic and osteogenic differentiation. Transcriptomically comparing IPFP-hSSCLCs and dorsal adipose depot (DSAT)-derived hSSCLCs through scRNA-seq, we further demonstrated IPFP-hSSCLCs are less differentiated but more motivated in expressing transcriptomes related to chondrogenic and osteogenic differentiation. Conclusion Our study first identified adipose tissue as an alternative but encouraging source for isolating hSSCLCs with intact SSC properties which might be promising in treating diseases related to bone and/or cartilage defects.

Background Shoulder soft tissue function reconstruction during tumor-type hemishoulder replacement is an important step to restore shoulder function. This study evaluates the functional prognosis and postoperative complications of ligament advanced reinforcement system (LARS)-assisted soft tissue functional reconstruction in tumor-type hemi-shoulder replacement. Materials and methods Twenty-two patients with an average age of 37.5 ± 17.8 years diagnosed with benign invasive tumors, primary malignant bone tumors, or bone metastases were enrolled in this study. The patient’s medical records (history and surgical details), histological sections, imaging files, oncological prognosis, functional prognosis, and postoperative complications were collected. The upper limb function and shoulder joint function were evaluated using the Musculoskeletal Tumor Society (MSTS) system and American Shoulder and Elbow Surgeons (ASES) scoring criteria, respectively. Results Twenty-two patients comprising 12 males and 10 females were enrolled. Overall, 9 patients had preoperative pathological fractures. The mean lesion length was 8.6 ± 3.0 cm. The local recurrence was observed in 3 cases, including 2 cases of osteosarcoma and 1 case of MGCT. A further 4 cases had pulmonary metastasis, including 2 cases with local tumor recurrence. The average postoperative MSTS score was 25.8 ± 1.7, and the score of postoperative ASES was 85.7 ± 6.0, both of which showed satisfactory functional recovery. Two cases experienced postoperative complications requiring surgical intervention, including one periprosthetic fracture and one giant cell granuloma. Prosthesis dislocation occurred in 1 case. None of the cases of periprosthetic infection or postoperative complications resulted in implant failure. Conclusions LARS-assisted soft tissue function reconstruction in benign and malignant proximal humerus tumors after a tumor-type hemi-shoulder replacement is an effective technical improvement, which can effectively repair the integrity of the joint capsule to restore joint stability, provide a medium for soft tissue attachment to rebuild the muscular dynamic system, and eliminate residual dead space around the prosthesis, effectively improving limb function and reduce postoperative infection complications.

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