Future research directions in acute lung injury: Summary of a National Heart, Lung, and Blood Institute Working Group

Acute lung injury (ALI) and its more severe form, the acute respiratory distress syndrome (ARDS), are syndromes of acute respiratory failure that result from acute pulmonary edema and inflammation. The development of ALI/ARDS is associated with several clinical disorders including direct pulmonary injury from pneumonia and aspiration as well as indirect pulmonary injury from trauma, sepsis, and other disorders such as acute pancreatitis and drug overdose. Although mortality from ALI/ARDS has decreased in the last decade, it remains high. Despite two major advances in treatment, low VT ventilation for ALI/ARDS and activated protein C for severe sepsis (the leading cause of ALI/ARDS), additional research is needed to develop specific treatments and improve understanding of the pathogenesis of these syndromes. The NHLBI convened a working group to develop specific recommendations for future ALI/ARDS research. Improved understanding of disease heterogeneity through use of evolving biologic, genomic, and genetic approaches should provide major new insights into pathogenesis of ALI. Cellular and molecular methods combined with animal and clinical studies should lead to further progress in the detection and treatment of this complex disease

Near-Infrared Fluorescent Oligodeoxyribonucleotide Reporters for Sensing NF-κB DNA Interactions In Vitro

Two types of reporters for optical sensing of NF-κB p50 protein-oligodeoxyribonucleotide (ODN) duplex interactions were designed and compared in vitro. The reporters were based on the effect of fluorescence resonance energy transfer (FRET) between the pair donor Cy5.5 near-infrared (NIR) fluorochrome and either 800CW emitting fluorescence dye acceptor (800CW-Cy), or a nonemitting QSY 21 dye quencher (QSY-Cy). The donor and the acceptor dyes were covalently linked to the complementary oligonucleotides, respectively: Cy dye was conjugated to 3′-thiol, whereas 800CW or QSY21 were conjugated to a hydrophilic internucleoside phosphate amino linker. The reporters were tested initially using recombinant NF-κB p50 protein binding assays. Both reporters were binding p50 protein, which protected oligonucleotide duplex from degradation in the presence of exonuclease. The incubation of 800CW-Cy reporter in the presence of control or IL-1β treated human endothelial cells showed the uptake of the reporter in the cytoplasm and the nucleus. The measurement of NIR fluorescence ratio (i.e. Cy5.5/800CW) showed a partial loss of FRET and the increased Cy5.5 fluorescence in nontreated, control cells. Thus, the specific p50 binding to ODN duplex reporters affected the donor–acceptor fluorochrome pair. NF-κB p50 exhibited the protective effect on FRET between NIR fluorochromes linked to the complementary strands of the reporter duplex

Influence of conduit angles on hemodynamics of modified Blalock-Taussig shunt : computational analysis of patient-specific virtual procedures

Currently, the modified Blalock-Taussig (mB-T) shunt is the most preferred surgery served as the first step of the staged procedures in the treatment of cyanotic congenital heart defect. A Gore-Tex conduit is used to surgically connect the systemic and pulmonary circulations. In the present study, we report on three-dimensional (3D) hemodynamic analysis of the effects of conduit anastomosis angles on hemodynamics of the mB-T shunt. We constructed a patient-specific 3D model after the mB-T shunt based on medical images and employed computer-aided design to reconstruct two new models with different anastomosis angles. The local pressure, blood flow distribution and wall shear stress were calculated. The results suggest the scheme of vertical anastomosis angle of the conduit on the pulmonary artery can increase the blood flow distribution from systemic circulation to two lungs and blood flows more smoothly in the conduit. The results are well congruent with our clinical experience. This indicates the numerical methods may be applied to investigate hemodynamics of the mB-T shunt for different surgical schemes.10 page(s

Tissue-Engineered Microvasculature to Reperfuse Isolated Renal Glomeruli

Kidney transplantation is often the most effective therapy for end-stage renal disease, but there are not enough donor organs to meet the rising demand. Tissue engineering of kidneys is a potential solution to this organ shortage. Achieving microvascular perfusion has been a major barrier to engineering tissues beyond thin muscularized sheets such as the bladder wall. Our laboratory has previously reported that human umbilical vein endothelial cells (ECs) transduced with the antiapoptotic protein Bcl-2 will spontaneously organize into perfused microvessels within type I collagen gels when implanted in immunodeficient mice. To test if this system can be used to perfuse more complex structures, we combined Bcl-2-transduced ECs (Bcl-2-ECs) with renal glomeruli, the specialized vascular filtration units of the kidney. Microdissected green fluorescent protein-expressing rat glomeruli suspended in type I collagen gels were implanted within immunodeficient mice with or without the inclusion of Bcl-2-ECs. Survival of rat glomeruli was enhanced by coimplantation with Bcl-2-ECs. Intravital rhodamine dextran injections demonstrated that surviving glomeruli were perfused through Bcl-2-EC-derived microvessels. Perfused glomeruli maintained podocin staining, but transmission electron microscopy revealed endothelial swelling and podocyte foot process effacement. Anastomosis of microvessels derived from Bcl-2-ECs with glomerular capillaries provides proof of concept that self-assembled microvessels can perfuse specialized organ structures such as glomeruli, but that perfusion alone may be insufficient to maintain normal structure