RESUMO
PURPOSE: To evaluate the effect of a one-time dose of insulin or insulin-like growth factor 1 (IGF-1) on cellular proliferation and migration of subacromial bursa tissue (SBT) over time. METHODS: SBT was harvested from over the rotator cuff tendon in 4 consecutive patients undergoing primary arthroscopic rotator cuff repair. SBT was cultured for 3 weeks in complete media until reaching confluence. The culture dishes were stored in a humidified, low oxygen tension (5% CO2) incubator at 37°C. SBT of each patient underwent treatment with a one-time dose of insulin or IGF-1, whereas nontreated SBT served as a negative control. Cellular proliferation and migration were evaluated after 24, 48, 72, and 96 hours of incubation. SBT-derived cells migrated in the detection field were visualized using fluorescent microscopy. RESULTS: Cellular proliferation at 24, 48, 72, and 96 hours was 1.40 ± 0.27, 1.00 ± 0.20, 1.47 ± 0.31, and 1.68 ± 0.28 for IGF-1; 1.44 ± 0.24, 1.15 ± 0.27, 1.60 ± 0.36, and 1.61 ± 0.32 for insulin; and 1.51 ± 0.35, 1.29 ± 0.33, 1.53 ± 0.35, and 1.57 ± 0.38 for nontreated SBT. Untreated SBT demonstrated a significantly greater proliferation when compared with IGF-1 and insulin within the first 48 hours, although this effect was found to subside by 96 hours. Cellular migration at 24, 48, 72, and 96 hours was 575.7 ± 45.0, 641.6 ± 77.7, 728.3 ± 122.9, and 752.3 ± 114.5 for IGF-1; 528.4 ± 31.3, 592.5 ± 69.8, 664.2 ± 115.2, and 695.6 ± 148.2 for insulin; and 524.4 ± 41.9, 564.4 ± 49.8, 653.2 ± 81.5, and 685.7 ± 115.5 for nontreated SBT. Insulin showed no difference in migration at each timepoint compared to nontreated SBT (P > .05, respectively). CONCLUSIONS: Insulin and IGF-1 initially inhibit cellular proliferation of human SBT, although this effect was found to subside by 96 hours. Further, neither insulin nor IGF-1 changed the slope of cellular migration over time. However, each treatment group demonstrated a significant increase in cellular proliferation and migration. CLINICAL RELEVANCE: In the setting of biologic augmentation of rotator cuff repair, the compatibility and synergistic effect of insulin on human SBT is highly limited.
RESUMO
PURPOSE: To evaluate the time required for colonies to develop from concentrated bone marrow aspirate (cBMA) and subacromial bursal tissue samples. METHODS: Samples of cBMA and subacromial bursa tissue were harvested from patients undergoing rotator cuff repair surgery between November 2014 and December 2019. Samples were analyzed for time to form colonies and number of colonies formed. The impact of age, sex, and cellularity (cBMA only) was analyzed. Samples were cultured and evaluated daily for colony formation in accordance with the guidelines of the International Society for Cellular Therapy. Demographic factors were analyzed for impact on time to form colonies and number of colonies formed. RESULTS: Samples of cBMA were obtained from 92 patients. Subacromial bursa tissue was obtained from 54 patients. For cBMA, older age was associated with more days to form colonies (P = .003), but sex (P = .955) and cellularity (P = .623) were not. For bursa, increased age was associated with longer time to form colonies (P = .002) but not sex (P = .804). Conclusions: Increased age (in cBMA and subacromial bursa tissue) and lower initial cellularity (in cBMA) are associated with longer time to form colonies in culture. CLINICAL RELEVANCE: Although connective tissue progenitor cells are widely used in orthopaedic practice, there are few metrics to determine their efficacy. Time to form colonies may serve as an important measurement for determining connective tissue progenitor cell viability for augmentation of rotator cuff repair. Subacromial bursa tissue may represent a viable alternative to cBMA for augmentation of rotator cuff repair, capable of forming colonies expediently in vivo.
RESUMO
PURPOSE: To classify subacromial bursal tissue using intraoperative and in vitro characteristics from specimens harvested during arthroscopic shoulder surgery. METHODS: Subacromial bursa was harvested over the rotator cuff from 48 patients (57 ± 10 years) undergoing arthroscopic shoulder surgery. Specimens were characterized intraoperatively by location (over rotator cuff tendon or muscle), tissue quality (percent of either fatty or fibrous infiltration), and vascularity before complete debridement. Nucleated cell counts were determined after 3 weeks incubation and histological sections were reviewed for degree of fatty infiltration and vascularity. Mesenchymal stem cell surface markers were counted via flow cytometry (n = 3) and cellular migration was observed using a fluoroscopic assay (n = 3). RESULTS: Intraoperatively, muscle bursa was found most often to have >50% fatty infiltration (n = 39), whereas tendon bursa showed majority fibrous tissue (n = 32). Cellular proliferation did not significantly differ according to intraoperative tissue quality. Intraoperative vascularity was associated with greater proliferation for highly vascular samples (P = 0.023). Tendon bursa demonstrated significantly greater proliferation potential than muscle bursa (P = 0.00015). Histologic assessment of fatty infiltration was moderately correlated with gross tissue fattiness (ρ = -0.626, P = 7.14 × 10-11). Flow cytometry showed that 90% to 100% of bursal cells were positive for MSC surface markers. Peak cellular migration rates occurred between 18 and 30 hours' incubation. CONCLUSIONS: Intraoperative and in vitro subacromial bursa characteristics were not found to reliably correlate with the degree of cellular proliferation. However, the anatomic location of subacromial bursa was consistently predictive of increased proliferation potential. Bursa-derived nucleated cells were confirmed to include mesenchymal stem cells with migratory potential. CLINICAL RELEVANCE: The anatomic distinction between muscle and tendon bursa provides a simple classification for predicting cellular activity.
