Repeatability of a Multi-segment Foot Model with a 15-Marker Set in Normal Children

BACKGROUND: The use of three-dimensional multi-segment foot models (3D MFMs) is increasing since they have superior ability to illustrate the effect of foot and ankle pathologies on intersegmental motion of the foot compared to single-segment foot model gait analysis. However, validation of the repeatability of the 3D MFMs is important for their clinical use. Although many MFMs have been validated in normal adults, research on MFM repeatability in children is lacking. The purpose of this study is to validate the intrasession, intersession, and interrater repeatability of an MFM with a 15-marker set (DuPont foot model) in healthy children. METHODS: The study included 20 feet of 20 healthy children (10 boys and 10 girls). We divided the participants into two groups of 10 each. One group was tested by the same operator in each test (intersession analysis), while the other group was tested by a different operator in each test (interrater analysis). The multiple correlation coefficient (CMC) and intraclass correlation coefficient (ICC) were calculated to assess repeatability. The difference between the two sessions of each group was assessed at each time point of gait cycle. RESULTS: The intrasession CMC and ICC values of all parameters showed excellent or very good repeatability. The intersession CMC of many parameters showed good or better repeatability. Interrater CMC and ICC values were generally lower for all parameters than intrasession and intersession. The mean gaps of all parameters were generally similar to those of the previous study. CONCLUSIONS: We demonstrated that 3D MFM using a 15-marker set had high intrasession, intersession, and interrater repeatability in the assessment of foot motion in healthy children but recommend some caution in interpreting the hindfoot parameters.

Platelet-Derived Growth Factor Receptor-Positive Pericytic Cells of White Adipose Tissue from Critical Limb Ischemia Patients Display Mesenchymal Stem Cell-Like Properties

BACKGROUND: The pericytes in the blood vessel wall have recently been identified to be important in regulating vascular formation, stabilization, remodeling, and function. We isolated and identified pericyte-like platelet-derived growth factor receptor beta-positive (PDGFRβ+) cells from the stromal vascular fraction (SVF) of adipose tissue from critical limb ischemia (CLI) patients and investigated their potential as a reliable source of stem cells for cell-based therapy. METHODS: De-identified subcutaneous fat tissues were harvested after amputation in CLI patients. Freshly isolated SVF cells and culture-expanded adipose-derived stem cells (ADSCs) were quantified using flow cytometry. A matrigel tube formation assay and multi-lineage differentiation were performed to assess pericytic and mesenchymal stem cell (MSC)-like characteristics of PDGFRβ+ ADSCs. RESULTS: PDGFRβ+ cells were located in the pericytic area of various sizes of blood vessels and coexpressed mesenchymal stem cell markers. PDGFRβ+ cells in freshly isolated SVF cells expressed a higher level of stem cell markers (CD34 and CXCR4) and mesenchymal markers (CD13, CD44, CD54, and CD90) than PDGFRβ– cells. In vitro expansion of PDGFRβ+ cells resulted in enrichment of the perivascular mesenchymal stem-like (PDGFRβ+/CD90+/CD45–/CD31–) cell fractions. The Matrigel tube formation assay revealed that PDGFRβ+ cells were located in the peritubular area. CONCLUSIONS: PDGFRβ+ ADSCs cells demonstrated a good multilineage differentiation potential. Pericyte-like PDGFRβ+ cells from the SVF of adipose tissue from CLI patients had MSC-like characteristics and could be amplified by in vitro culture with preservation of their cell characteristics. We believe PDGFRβ+ cells in the SVF of adipose tissue can be used as a reliable source of stem cells even in CLI patients.