Robert J. Freishtat

Asynchronous remodeling is a driver of failed regeneration in Duchenne muscular dystrophy

In Duchenne muscular dystrophy, asynchronous regeneration in microenvironments within muscle tissue results in development of fibrosis in lieu of global muscle recovery.

Sepsis Alters the Megakaryocyte–Platelet Transcriptional Axis Resulting in Granzyme B–mediated Lymphotoxicity

RATIONALE Sepsis-related mortality results in part from immunodeficiency secondary to profound lymphoid apoptosis. The biological mechanisms responsible are not understood. OBJECTIVES Because recent evidence shows that platelets are involved in microvascular inflammation and that they accumulate in lymphoid microvasculature in sepsis, we hypothesized a direct role for platelets in sepsis-related lymphoid apoptosis. METHODS We studied megakaryocytes and platelets from a murine-induced sepsis model, with validation in septic children, which showed induction of the cytotoxic serine protease granzyme B. MEASUREMENTS AND MAIN RESULTS Platelets from septic mice induced marked apoptosis of healthy splenocytes ex vivo. Platelets from septic granzyme B null (-/-) mice showed no lymphotoxicity. CONCLUSIONS Our findings establish a conceptual advance in sepsis: Septic megakaryocytes produce platelets with acutely altered mRNA profiles, and these platelets mediate lymphotoxicity via granzyme B. Given the contribution of lymphoid apoptosis to sepsis-related mortality, modulation of platelet granzyme B becomes an important new target for investigation and therapy.

miRTarVis: an interactive visual analysis tool for microRNA-mRNA expression profile data

BackgroundMicroRNAs (miRNA) are short nucleotides that down-regulate its target genes. Various miRNA target prediction algorithms have used sequence complementarity between miRNA and its targets. Recently, other algorithms tried to improve sequence-based miRNA target prediction by exploiting miRNA-mRNA expression profile data. Some web-based tools are also introduced to help researchers predict targets of miRNAs from miRNA-mRNA expression profile data. A demand for a miRNA-mRNA visual analysis tool that features novel miRNA prediction algorithms and more interactive visualization techniques exists.ResultsWe designed and implemented miRTarVis, which is an interactive visual analysis tool that predicts targets of miRNAs from miRNA-mRNA expression profile data and visualizes the resulting miRNA-target interaction network. miRTarVis has intuitive interface design in accordance with the analysis procedure of load, filter, predict, and visualize. It predicts targets of miRNA by adopting Bayesian inference and MINE analyses, as well as conventional correlation and mutual information analyses. It visualizes a resulting miRNA-mRNA network in an interactive Treemap, as well as a conventional node-link diagram. miRTarVis is available at http://hcil.snu.ac.kr/~rati/miRTarVis/index.html.ConclusionsWe reported findings from miRNA-mRNA expression profile data of asthma patients using miRTarVis in a case study. miRTarVis helps to predict and understand targets of miRNA from miRNA-mRNA expression profile data.

The Global Emergence of Unregulated Stem Cell Treatments for Respiratory Diseases. Professional Societies Need to Act.

Laertis Ikonomou, Robert J. Freishtat, Darcy E. Wagner, Angela Panoskaltsis-Mortari, and Daniel J. Weiss The Pulmonary Center, Boston University School of Medicine and Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, Massachusetts; George Washington University School of Medicine and Children’s National Medical Center, Washington, DC; Comprehensive Pneumology Center, Ludwig-Maximilians-Universität, Munich, Germany; Departments of Pediatrics and Medicine, University of Minnesota, Minneapolis, Minnesota; and University of Vermont College of Medicine, Burlington, Vermont

Circulating adipocyte‐derived exosomal MicroRNAs associated with decreased insulin resistance after gastric bypass

Exosomes from obese adipose contain dysregulated microRNAs linked to insulin signaling, as compared with lean controls, providing a direct connection between adiposity and insulin resistance. This study tested the hypotheses that gastric bypass surgery and its subsequent weight loss would normalize adipocyte‐derived exosomal microRNAs associated with insulin signaling and the associated metabolome related to glucose homeostasis.

VBP15, a glucocorticoid analogue, is effective at reducing allergic lung inflammation in mice.

Asthma is a chronic inflammatory condition of the lower respiratory tract associated with airway hyperreactivity and mucus obstruction in which a majority of cases are due to an allergic response to environmental allergens. Glucocorticoids such as prednisone have been standard treatment for many inflammatory diseases for the past 60 years. However, despite their effectiveness, long-term treatment is often limited by adverse side effects believed to be caused by glucocorticoid receptor-mediated gene transcription. This has led to the pursuit of compounds that retain the anti-inflammatory properties yet lack the adverse side effects associated with traditional glucocorticoids. We have developed a novel series of steroidal analogues (VBP compounds) that have been previously shown to maintain anti-inflammatory properties such as NFκB-inhibition without inducing glucocorticoid receptor-mediated gene transcription. This study was undertaken to determine the effectiveness of the lead compound, VBP15, in a mouse model of allergic lung inflammation. We show that VBP15 is as effective as the traditional glucocorticoid, prednisolone, at reducing three major hallmarks of lung inflammation—NFκB activity, leukocyte degranulation, and pro-inflammatory cytokine release from human bronchial epithelial cells obtained from patients with asthma. Moreover, we found that VBP15 is capable of reducing inflammation of the lung in vivo to an extent similar to that of prednisone. We found that prednisolone–but not VBP15 shortens the tibia in mice upon a 5 week treatment regimen suggesting effective dissociation of side effects from efficacy. These findings suggest that VBP15 may represent a potent and safer alternative to traditional glucocorticoids in the treatment of asthma and other inflammatory diseases.

Issues in children's hospital disaster preparedness

Abstract On September 11, 2001, Childrens National Medical Center (CNMC) in Washington, D.C. was the most proximate pediatric tertiary care center facility to the disaster at the Pentagon. The hospitals multiple casualty plan was activated; while no child victims presented for care, the CNMC staff realized that their plan, like most or all childrens hospital disaster plans around the country, was inadequate to deal with a true mass casualty incident involving mass trauma patients, biological or chemical weapons. The authors review the elements of a successful mass casualty response and describe their experiences during the events of and following September 11, 2001.

Overweight children: Are they at increased risk for severe injury in motor vehicle collisions?

BACKGROUND Obesity is an epidemic in the United States. The relationship between traumatic injury and obesity in children is not well-studied. We hypothesized that overweight children suffer more severe injuries, different distributions of injuries and improper use of restraints in motor vehicle collisions. METHODS We conducted a secondary analysis of the CIREN database of motor vehicle collisions of subjects 2-17 years old. Overweight was defined as a BMI percentile for age >85%. Significant injury was an Injury Severity Score (ISS) >15 or an Abbreviated Injury Scale (AIS) score greater than one. Further analysis looked at injuries classified as head, trunk, or extremities and appropriateness of restraints. Odds ratios compared the overweight to lean groups. RESULTS 335 subjects met inclusion criteria with 35.5% of cases being overweight. For significant injury, overweight cases had an odds ratio of 1.2 [95% CI: 0.8-1.9]. Analysis by AIS for overall significant injury and to specific body regions also did not show any significant associations. Overweight versus lean subjects had an odds ratio of 1.3 [95% CI: 0.8-2.1] for improper use of restraints. CONCLUSIONS We found no significant relationship between pediatric injury severity, distribution of injuries, or restraint use and being overweight. Limitations of this study were the small sample size in this database and the large number of unrestrained subjects.

Microbial Diversity Within the Airway Microbiome in Chronic Pediatric Lung Diseases.

The study of the airway microbiome in children is an area of emerging research, especially in relation to the role microbial diversity may play in acute and chronic inflammation. Three such pediatric airway diseases include cystic fibrosis, asthma, and chronic lung disease of prematurity. In cystic fibrosis, the presence of Pseudomonas spp. is associated with decreased microbial diversity. Decreasing microbial diversity is also associated with poor lung function. In asthma, early viral infections appear to drive changes in bacterial diversity which may be associated with asthma risk. Premature infants with Ureaplasma spp. are at higher risk for chronic lung disease due to inflammation. Microbiome changes due to prematurity also appear to affect the inflammatory response to viral infections post-natally. Importantly, microbial diversity can be measured using metataxonomic (e.g., 16S rRNA sequencing) and metagenomic (e.g., shotgun sequencing) approaches. A metagenomics approach may be preferable as it can provide further granularity of the sample composition, identifying the bacterial species or strain, information on additional microbial components, including fungal and viral components, information about functional genomics of the microbiome, and information about antimicrobial resistance mutations. Future studies of pediatric airway diseases incorporating these techniques may provide evidence for new treatment approaches for these vulnerable patient populations.

Conditional reprogramming of pediatric airway epithelial cells: a new human model to investigate early life respiratory disorders

Airway epithelial cells (AEC) are quite difficult to access in newborns and infants. It is critically important to develop robust life‐extended models to conduct translational studies in this age group. We propose the use of a recently described cell culture technology (conditionally reprogrammed cells—CRC) to generate continuous primary cell cultures from nasal and bronchial AEC of young children.