Induced pluripotent stem cell models from X-linked adrenoleukodystrophy patients.

OBJECTIVE: Because of a lack of an appropriate animal model system and the inaccessibility of human oligodendrocytes in vivo, X-linked adrenoleukodystrophy (X-ALD)-induced pluripotent stem cells (iPSCs) would provide a unique cellular model for studying etiopathophysiology and development of therapeutics for X-ALD. METHODS: We generated and characterized iPSCs of the 2 major types of X-ALD, childhood cerebral ALD (CCALD) and adrenomyeloneuropathy (AMN), and differentiated them into oligodendrocytes and neurons. We evaluated disease-relevant phenotypes by pharmacological and genetic approaches. RESULTS: We established iPSCs from the patients with CCALD and AMN. Both CCALD and AMN iPSCs normally differentiated into oligodendrocytes, the cell type primarily affected in the X-ALD brain, indicating no developmental defect due to the ABCD1 mutations. Although low in X-ALD iPSCs, very long chain fatty acid (VLCFA) level was significantly increased after oligodendrocyte differentiation. VLCFA accumulation was much higher in CCALD oligodendrocytes than AMN oligodendrocytes but was not significantly different between CCALD and AMN neurons, indicating that the severe clinical manifestations in CCALD might be associated with abnormal VLCFA accumulation in oligodendrocytes. Furthermore, the abnormal accumulation of VLCFA in the X-ALD oligodendrocytes can be reduced by the upregulated ABCD2 gene expression after treatment with lovastatin or 4-phenylbutyrate. INTERPRETATION: X-ALD iPSC model recapitulates the key events of disease development (ie, VLCFA accumulation in oligodendrocytes), provides new clues for better understanding of the disease, and allows for early and accurate diagnosis of the disease subtypes. X-ALD oligodendrocytes can be a useful cell model system to develop new therapeutics for treating X-ALD.

Miniscrew stability evaluated with computerized tomography scanning.

INTRODUCTION: In this study, we aimed to determine the effect of bone mineral density (BMD), cortical bone thickness (CBT), screw position, and screw design on the stability of miniscrews. METHODS: Ninety-six miniscrews of both cylindrical and tapered types were placed in 6 beagle dogs. The BMD and CBT were measured by computerized tomography and correlated with the placement and removal torque and mobility. A regression equation to predict the placement torque was calculated based on BMD, CBT, screw type, and screw position. RESULTS: The placement torque showed a positive correlation in the order of removal torque (0.66), BMD of the cortical bone (0.58), and CBT (0.48). Placement and removal torque values were significantly higher in the mandible compared with the maxilla. Tapered miniscrews had higher placement torque than did the cylindrical type (P <0.001). However, the removal torque was similar in both groups. Placement torque was affected by screw position, screw type, and BMD of cortical bone, in that order. CONCLUSIONS: BMD of cortical bone, screw type, and screw position significantly influence the primary stability of miniscrews.

Human embryonic stem cells (hESCs) cultured under distinctive feeder-free culture conditions display global gene expression patterns similar to hESCs from feeder-dependent culture conditions.

Human embryonic stem cell (hESC)-based assay systems and genetically modified hESCs are very useful tools for screening drugs that regulate stemness and differentiation and for studying the molecular mechanisms involved in hESC fate determination. For these types of studies, feeder cell-dependent cultures of hESCs are often problematic because the physiology of the feeder cells is perturbed by the drug treatments or genetic modifications, which potentially obscures research outcomes. In this study, we evaluated three commonly used feeder-free culture conditions to determine whether they supported the undifferentiated growth of hESCs and to determine whether the hESCs grown in these conditions displayed gene expression patterns that were similar to the expression patterns of feeder cell-dependent hESCs. Our results demonstrate that hESCs grown in the three feeder-free conditions expressed undifferentiation marker genes as strongly as hESCs that were grown in the feeder-dependent cultures. Furthermore, genome-wide gene expression profiles indicated that the gene expression patterns of hESCs that were grown under feeder-free or feeder-dependent culture conditions were highly similar. These results indicate that the feeder-free culture conditions support the undifferentiated growth of hESCs as effectively as the feeder-dependent culture conditions. Therefore, feeder-free culture conditions are potentially suitable for drug screening and for the genetic manipulation of hESCs in basic research.