Ectopic PDX-1 Expression Directly Reprograms Human Keratinocytes along Pancreatic Insulin-Producing Cells Fate

BACKGROUND: Cellular differentiation and lineage commitment have previously been considered irreversible processes. However, recent studies have indicated that differentiated adult cells can be reprogrammed to pluripotency and, in some cases, directly into alternate committed lineages. However, although pluripotent cells can be induced in numerous somatic cell sources, it was thought that inducing alternate committed lineages is primarily only possible in cells of developmentally related tissues. Here, we challenge this view and analyze whether direct adult cell reprogramming to alternate committed lineages can cross the boundaries of distinct developmental germ layers. METHODOLOGY/PRINCIPAL FINDINGS: We ectopically expressed non-integrating pancreatic differentiation factors in ectoderm-derived human keratinocytes to determine whether these factors could directly induce endoderm-derived pancreatic lineage and β-cell-like function. We found that PDX-1 and to a lesser extent other pancreatic transcription factors, could rapidly and specifically activate pancreatic lineage and β-cell-like functional characteristics in ectoderm-derived human keratinocytes. Human keratinocytes transdifferentiated along the β cell lineage produced processed and secreted insulin in response to elevated glucose concentrations. Using irreversible lineage tracing for KRT-5 promoter activity, we present supporting evidence that insulin-positive cells induced by ectopic PDX-1 expression are generated in ectoderm derived keratinocytes. CONCLUSIONS/SIGNIFICANCE: These findings constitute the first demonstration of human ectoderm cells to endoderm derived pancreatic cells transdifferentiation. The study represents a proof of concept which suggests that transcription factors induced reprogramming is wider and more general developmental process than initially considered. These results expanded the arsenal of adult cells that can be used as a cell source for generating functional endocrine pancreatic cells. Directly reprogramming somatic cells into alternate desired tissues has important implications in developing patient-specific, regenerative medicine approaches

Carina Angle Measurements for Diagnosis of Patent Ductus Arteriosus in Preterm Infants

&lt;i&gt;Background:&lt;/i&gt; Bedside diagnosis of patent ductus arteriosus (PDA) continues to be important, especially when echocardiography is not readily available. &lt;i&gt;Objective:&lt;/i&gt; The aim of our study was to evaluate whether measurement of left main bronchus displacement portrayed on a chest X-ray as a widened carina angle (CA) may support the presumptive diagnosis of PDA. &lt;i&gt;Methods:&lt;/i&gt; Displacement of the left bronchus was assessed by measuring the angle between the two main bronchi at the level of the carina in 47 infants with PDA and 73 with no evidence of ductus, all born before 32 weeks of gestation. &lt;i&gt;Results:&lt;/i&gt; The PDA group had a significantly wider CA (99.9 ± 12.1°) compared to the no-ductus group (72.9 ±15.7°; p &lt; 0.001). Resolution of the PDA resulted in closure of the CA (62.3 ± 10.8°). We observed a significant and positive association between an increased CA measurement and PDA occurrence (OR = 1.7, 95% CI = 1.4–2.1). A CA cutoff point of 90° had the highest sensitivity (85%) and specificity (85%) for indicating the presence of PDA. &lt;i&gt;Conclusions:&lt;/i&gt; Measurement of the CA is an easily accessible and reliable tool that may assist in establishing the diagnosis of PDA.</jats:p