Introduction. Parathyroid hormone 1–34 (PTH) has been reported to accelerate fracture healing. Previously, we demonstrated human fracture hematoma contained osteo-/chondro-progenitor cells. To date, there has been no study investigating the effect of PTH on fracture hematoma-derived cells (HCs) in vitro. Hypothesis. We hypothesized PTH treatment affected osteogenesis and chondrogenesis of HCs. Materials & Methods. HCs were divided into 3 groups: control (growth medium), PTH (−) (osteogenic or chondrogenic medium (OM or CM)), and PTH (+) group (OM or CM with PTH). Cell proliferation was assessed by MTS assay. Osteogenesis was assessed by alkaline phosphatase (ALP) activity, real-time PCR, and Alizarin red S staining. Chondrogenesis was assessed by real-time PCR and Safranin-O staining. Results. There was no significant difference in proliferation among 3 groups. ALP activity and expression levels of ALP and Runx2 in PTH (+) group were comparable with PTH (−) group. HCs in PTH (−) and PTH (+) group were strongly stained with Alizarin red S staining. The expression levels of collagen-II and -X in PTH (+) group were significantly lower than PTH (−) group. Pellets in PTH (+) group were slightly stained with Safranin-O staining. Discussion & Conclusion. Our results revealed that PTH treatment did not affect osteogenesis and inhibited chondrogenesis of HCs. PTH treatment after fracture may positively affect other cells such as periosteum-derived cells and circulating stem cells

The scarcity of mesenchymal stem cells (MSCs) in iliac crest bone marrow aspirate (ICBMA), and the expense and time in culturing cells, has led to the search for alternative harvest sites. The reamer-irrigation-aspirator (RIA) provides continuous irrigation and suction during reaming of long bones. The aspirated contents pass via a filter, trapping bony fragments, before moving into a ‘waste’ bag from which MSCs have been previously isolated. We examined the liquid and solid phases, performed a novel digestion of the solid phase, and made a comparative assessment in terms of number, phenotype and differentiation capacity with matched ICBMA.

The solid fraction from the filtrate was digested for 60 minutes at 37°C with collagenase. Enumeration was performed via the colony-forming unit fibroblast (CFU-F) assay. Passage (P2) cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages, and their phenotypes assessed using flow cytometry (CD33, CD34, CD45, CD73, CD90, and CD105).

MSCs from the RIA phases were able to differentiate at least as well as those from ICBMA, and all fractions had phenotypes consistent with other established sources. The median number of colonies for the three groups was: ICBMA = 8.5 (2 to 86), RIA-liquid = 19.5 (4 to 90), RIA-solid = 109 (67 to 200) per 200 μl. The mean total yield of cells for the three groups was: ICBMA = 920 (0 to 4275), RIA-liquid = 114 983 (16 500 to 477 750), RIA-solid = 12 785 (7210 to 28 475).

The RIA filtrate contains large numbers of MSCs that could potentially be extracted without enzymatic digestion and used for bone repair without prior cell expansion.