Virtual Histology of Transgenic Mouse Embryos for High-Throughput Phenotyping

A bold new effort to disrupt every gene in the mouse genome necessitates systematic, interdisciplinary approaches to analyzing patterning defects in the mouse embryo. We present a novel, rapid, and inexpensive method for obtaining high-resolution virtual histology for phenotypic assessment of mouse embryos. Using osmium tetroxide to differentially stain tissues followed by volumetric X-ray computed tomography to image whole embryos, isometric resolutions of 27 μm or 8 μm were achieved with scan times of 2 h or 12 h, respectively, using mid-gestation E9.5–E12.5 embryos. The datasets generated by this method are immediately amenable to state-of-the-art computational methods of organ patterning analysis. This technique to assess embryo anatomy represents a significant improvement in resolution, time, and expense for the quantitative, three-dimensional analysis of developmental patterning defects attributed to genetically engineered mutations and chemically induced embryotoxicity

Human Platelet-Rich Plasma- and Extracellular Matrix-Derived Peptides Promote Impaired Cutaneous Wound Healing In Vivo

Previous work in our laboratory has described several pro-angiogenic short peptides derived from endothelial extracellular matrices degraded by bacterial collagenase. Here we tested whether these peptides could stimulate wound healing in vivo. Our experiments demonstrated that a peptide created as combination of fragments of tenascin X and fibrillin 1 (comb1) applied into cranial dermal wounds created in mice treated with cyclophosphamide to impair wound healing, can improve the rate of wound closure. Furthermore, we identify and characterize a novel peptide (UN3) created and modified from two naturally-occurring peptides, which are present in human platelet-rich plasma. In vitro testing of UN3 demonstrates that it causes a 50% increase in endothelial proliferation, 250% increase in angiogenic response and a tripling of epithelial cell migration in response to injury. Results of in vivo experiments where comb1 and UN3 peptides were added together to cranial wounds in cyclophosphamide-treated mice leads to improvement of wound vascularization as shown by an increase of the number of blood vessels present in the wound beds. Application of the peptides markedly promotes cellular responses to injury and essentially restores wound healing dynamics to those of normal, acute wounds in the absence of cyclophosphamide impairment. Our current work is aimed at understanding the mechanisms underlying the stimulatory effects of these peptides as well as identification of the cellular receptors mediating these effects.National Institutes of Health (U.S.) (Grant EY15125)National Institutes of Health (U.S.) (Grant EY19533)Wound Care Partners, LL

Quantitative comparison of myocardial fiber structure between mice, rabbit, and sheep using diffusion tensor cardiovascular magnetic resonance

<p>Abstract</p> <p>Background</p> <p>Accurate interpretations of cardiac functions require precise structural models of the myocardium, but the latter is not available always and for all species. Although scaling or substitution of myocardial fiber information from alternate species has been used in cardiac functional modeling, the validity of such practice has not been tested.</p> <p>Methods</p> <p>Fixed mouse (n = 10), rabbit (n = 6), and sheep (n = 5) hearts underwent diffusion tensor imaging (DTI). The myocardial structures in terms of the left ventricular fiber orientation helix angle index were quantitatively compared between the mouse rabbit and sheep hearts.</p> <p>Results</p> <p>The results show that significant fiber structural differences exist between any two of the three species. Specifically, the subepicardial fiber orientation, and the transmural range and linearity of fiber helix angles are significantly different between the mouse and either rabbit or sheep. Additionally, a significant difference was found between the transmural helix angle range between the rabbit and sheep. Across different circumferential regions of the heart, the fiber orientation was not found to be significantly different.</p> <p>Conclusions</p> <p>The current study indicates that myocardial structural differences exist between different size hearts. An immediate implication of the present findings for myocardial structural or functional modeling studies is that caution must be exercised when extrapolating myocardial structures from one species to another.</p

Perspectives on Disconnects Between Scientific Information and Management Decisions on Post-fire Recovery in Western US

Environmental regulations frequently mandate the use of "best available" science, but ensuring that it is used in decisions around the use and protection of natural resources is often challenging. In the Western US, this relationship between science and management is at the forefront of post-fire land management decisions. Recent fires, post-fire threats (e.g. flooding, erosion), and the role of fire in ecosystem health combine to make post-fire management highly visible and often controversial. This paper uses post-fire management to present a framework for understanding why disconnects between science and management decisions may occur. We argue that attributes of agencies, such as their political or financial incentives, can limit how effectively science is incorporated into decision-making. At the other end of the spectrum, the lack of synthesis or limited data in science can result in disconnects between science-based analysis of post-fire effects and agency policy and decisions. Disconnects also occur because of the interaction between the attributes of agencies and the attributes of science, such as their different spatial and temporal scales of interest. After offering examples of these disconnects in post-fire treatment, the paper concludes with recommendations to reduce disconnects by improving monitoring, increasing synthesis of scientific findings, and directing social-science research toward identifying and deepening understanding of these disconnects

Effect of alirocumab on mortality after acute coronary syndromes. An analysis of the ODYSSEY OUTCOMES randomized clinical trial

Background: Previous trials of PCSK9 (proprotein convertase subtilisin-kexin type 9) inhibitors demonstrated reductions in major adverse cardiovascular events, but not death. We assessed the effects of alirocumab on death after index acute coronary syndrome. Methods: ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) was a double-blind, randomized comparison of alirocumab or placebo in 18 924 patients who had an ACS 1 to 12 months previously and elevated atherogenic lipoproteins despite intensive statin therapy. Alirocumab dose was blindly titrated to target achieved low-density lipoprotein cholesterol (LDL-C) between 25 and 50 mg/dL. We examined the effects of treatment on all-cause death and its components, cardiovascular and noncardiovascular death, with log-rank testing. Joint semiparametric models tested associations between nonfatal cardiovascular events and cardiovascular or noncardiovascular death. Results: Median follow-up was 2.8 years. Death occurred in 334 (3.5%) and 392 (4.1%) patients, respectively, in the alirocumab and placebo groups (hazard ratio [HR], 0.85; 95% CI, 0.73 to 0.98; P=0.03, nominal P value). This resulted from nonsignificantly fewer cardiovascular (240 [2.5%] vs 271 [2.9%]; HR, 0.88; 95% CI, 0.74 to 1.05; P=0.15) and noncardiovascular (94 [1.0%] vs 121 [1.3%]; HR, 0.77; 95% CI, 0.59 to 1.01; P=0.06) deaths with alirocumab. In a prespecified analysis of 8242 patients eligible for ≥3 years follow-up, alirocumab reduced death (HR, 0.78; 95% CI, 0.65 to 0.94; P=0.01). Patients with nonfatal cardiovascular events were at increased risk for cardiovascular and noncardiovascular deaths (P<0.0001 for the associations). Alirocumab reduced total nonfatal cardiovascular events (P<0.001) and thereby may have attenuated the number of cardiovascular and noncardiovascular deaths. A post hoc analysis found that, compared to patients with lower LDL-C, patients with baseline LDL-C ≥100 mg/dL (2.59 mmol/L) had a greater absolute risk of death and a larger mortality benefit from alirocumab (HR, 0.71; 95% CI, 0.56 to 0.90; Pinteraction=0.007). In the alirocumab group, all-cause death declined wit h achieved LDL-C at 4 months of treatment, to a level of approximately 30 mg/dL (adjusted P=0.017 for linear trend). Conclusions: Alirocumab added to intensive statin therapy has the potential to reduce death after acute coronary syndrome, particularly if treatment is maintained for ≥3 years, if baseline LDL-C is ≥100 mg/dL, or if achieved LDL-C is low. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01663402

The <em>Drosophila</em> PGC-1α Homolog <em>spargel</em> Modulates the Physiological Effects of Endurance Exercise

<div><p>Endurance exercise is an inexpensive intervention that is thought to provide substantial protection against several age-related pathologies, as well as inducing acute changes to endurance capacity and metabolism. Recently, it has been established that endurance exercise induces conserved alterations in physiological capacity in the invertebrate <em>Drosophila</em> model. If the genetic factors underlying these exercise-induced physiological alterations are widely conserved, then invertebrate genetic model systems will become a valuable tool for testing of genetic and pharmacological mimetics for endurance training. Here, we assess whether the <em>Drosophila</em> homolog of the vertebrate exercise response gene PGC-1α <em>spargel (srl)</em> is necessary or sufficient to induce exercise-dependent phenotypes. We find that reduction of <em>srl</em> expression levels acutely compromises negative geotaxis ability and reduces exercise-induced improvement in both negative geotaxis and time to exhaustion. Conversely, muscle/heart specific <em>srl</em> overexpression improves negative geotaxis and cardiac performance in unexercised flies. In addition, we find that <em>srl</em> overexpression mimics some, but not all, exercise-induced phenotypes, suggesting that other factors also act in parallel to <em>srl</em> to regulate exercise-induced physiological changes in muscle and heart.</p> </div

<i>srl</i> expression in muscle and heart acts synergistically with exercise to protect from cardiac failure.

<p>(<b>A</b>) External electrical pacing assays conducted on 4-day old <i>y¹w^67c23</i>, UAS-<i>srl</i>;<i>mef2</i>-Gal4, and <i>srl¹</i> flies show reduced stress-induced failure rates in UAS-<i>srl</i>;<i>mef2</i>-Gal4 flies when compared with <i>y¹w^67c23</i> controls (F-test, p = 0.0178). Pacing assays conducted on 25 day-old exercised and unexercised (<b>B</b>) <i>y¹w^67c23</i> and UAS-<i>srl</i>;<i>mef2</i>-Gal4 and (<b>C</b>) <i>y¹w^67c23</i> and <i>srl¹</i> flies show decreased stress-induced failure rates in exercised flies relative to unexercised age-matched siblings in all genotypes (F-test, p = 0.0054, 0.0044, and 0.0394 for control, <i>srl</i> overexperssing and <i>srl</i> mutant flies respectively). Exercised flies overexpressing <i>srl</i> in the muscle also showed a decreased stress-induced failure rate when compared to exercised <i>y¹w^67c23</i> flies (F-test, p = 0.0430). All <i>n</i> were between 56–122.</p

<i>srl</i> is required, but not sufficient, for exercise-induced improvement to endurance capacity.

<p>(<b>A</b>) Time to exhaustion assays conducted on <i>y¹w^67c23</i>, UAS-<i>srl</i>;<i>mef2</i>-Gal4, and <i>srl¹</i> flies. Flies overexpressing <i>srl</i> in the muscle increase time to exhaustion as compared to <i>y¹w^67c23</i> control flies (<i>t</i>-test: p = 0.0031). (<b>B</b>) Change in time to exhaustion in exercised flies as compared to unexercised flies of the same genotype. Wild-type and <i>srl</i> overexpressing flies increase time to exhaustion as a result of exercise (<i>t</i>-test, exercised and unexercised flies: p = 0.0001 and 0.0004, respectively for each genotype) to the same extent, while <i>srl¹</i> mutant flies in fact decrease time to exhaustion after exercise training (<i>t</i>-test, exercised and unexercised <i>srl¹</i>: p = 0.0044, exercised <i>y¹w^67c23</i> and exercised <i>srl¹</i>: p = 0.0005). (<b>C</b>) Endurance climbing assays conducted on 25 day-old <i>y¹w^67c23</i>, UAS-<i>srl</i>;<i>mef2</i>-Gal4, and <i>srl¹</i> flies. Unexercised <i>srl¹</i> display a decrease in climbing speed compared to unexercised <i>y¹w^67c23</i> (multivariate regression, genotype effect: p = 0.0011), while unexercised <i>srl</i> overexpressers do not statistically differ from unexercised <i>y¹w^67c23</i> flies. (<b>D</b>) After training, both exercised <i>y¹w^67c23</i> and exercised UAS-<i>srl</i>;<i>mef2</i>-Gal4 flies show increased climbing speed when compared to unexercised control flies (multivariate regression, genotype effect: p = 0.0002 and p<0.0001, respectively), though <i>srl¹</i> flies show no significant improvement (multivariate regression, genotype effect: p = 0.817). Survival rates during treatment of (<b>E</b>) unexercised and (<b>F</b>) exercised <i>y¹w^67c23</i>, UAS-<i>srl</i>;<i>mef2</i>-Gal4, and <i>srl¹</i> flies. Unexercised flies were placed on the training machine but not allowed to run. Survival during treatment is statistically improved by exercise in all three genotypes (multivariate regression; treatment-by-age, all p values<0.012). Exercised UAS-<i>srl</i>;<i>mef2</i>-Gal4 flies also show increased survival compared to exercised <i>y¹w^67c23</i> flies (multivariate regression, genotype effect, p = 0.0027).</p